Patent Application
20240214947
The disclosure relates to an operation of a terminal and a base station in a wireless communication system. Specifically, the disclosure relates to a method of reporting an uplink power headroom in a wireless communication system and a device capable of performing the same.
5G mobile communication technology defines a wide frequency band to enable a fast transmission speed and new services, and may be implemented not only in a frequency (‘sub 6 GHz’) band of 6 GHz or less such as 3.5 GHz, but also in an ultra high frequency band (‘above 6 GHz’) called a mmWave such as 28 GHz and 39 GHz. Further, in the case of 6G mobile communication technology, which is referred to as a beyond 5G system, in order to achieve a transmission speed that is 50 times faster than that of 5G mobile communication technology and ultra-low latency reduced to 1/10 compared to that of 5G mobile communication technology, implementations in terahertz bands (e.g., such as 95 GHz to 3 terahertz (3 THz) band) are being considered.
In the early days of 5G mobile communication technology, with the goal of satisfying the service support and performance requirements for an enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), standardization has been carried out for beamforming and massive MIMO for mitigating a path loss of radio waves in an ultra-high frequency band and increasing a propagation distance of radio waves, support for various numerologies (multiple subcarrier spacing operation, and the like) for efficient use of ultra-high frequency resources and dynamic operation for slot formats, initial access technology for supporting multi-beam transmission and broadband, a definition and operation of a band-width part (BWP), a new channel coding method such as low density parity check (LDPC) code for large capacity data transmission and polar code for high reliable transmission of control information, L2 pre-processing, and network slicing that provides a dedicated network specialized for specific services.
Currently, discussions are ongoing to improve initial 5G mobile communication technology and enhance a performance thereof in consideration of services that 5G mobile communication technology was intended to support, and physical layer standardization for technologies such as vehicle-to-everything (V2X) for helping driving determination of an autonomous vehicle and increasing user convenience based on a location and status information of the vehicle transmitted by the vehicle, new radio unlicensed (NR-U) for the purpose of a system operation that meets various regulatory requirements in unlicensed bands, NR UE power saving, a non-terrestrial network (NTN), which is direct UE-satellite communication for securing coverage in areas where communication with a terrestrial network is impossible, and positioning is in progress.
Further, standardization in the field of air interface architecture/protocol for technologies such as industrial Internet of things (IIoT) for supporting new services through linkage and convergence with other industries, integrated access and backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and 2-step RACH for NR that simplifies a random access procedure is also in progress, and standardization in the field of system architecture/service for 5G baseline architecture (e.g., service based architecture, service based interface) for applying network functions virtualization (NFV) and software-defined networking (SDN) technologies, mobile edge computing (MEC) that receives services based on a location of a UE, and the like is also in progress.
When such a 5G mobile communication system is commercialized, connected devices in an explosive increase trend will be connected to communication networks; thus, it is expected that function and performance enhancement of a 5G mobile communication system and integrated operation of connected devices will be required. To this end, new research on eXtended reality (XR) for efficiently supporting augmented reality (AR), virtual reality (VR), mixed reality (MR), and the like, 5G performance improvement and complexity reduction using artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication will be conducted.
Further, the development of such a 5G mobile communication system will be the basis for the development of full duplex technology for improving frequency efficiency and system network of 6G mobile communication technology, satellite, AI-based communication technology that utilizes artificial intelligence (AI) from a design stage and that realizes system optimization by internalizing end-to-end AI support functions, and next generation distributed computing technology that realizes complex services beyond the limits of UE computing capabilities by utilizing ultra-high-performance communication and computing resources as well as a new waveform for ensuring coverage in a terahertz band of 6G mobile communication technology, full dimensional MIMO (FD-MIMO), multi-antenna transmission technologies such as an array antenna and large scale antenna, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) technology.
Various embodiments of the disclosure provide a method and device capable of effectively providing a service in a mobile communication system.
According to an embodiment of the disclosure, a method performed by a terminal in a communication system is provided. The method includes receiving power headroom reporting (PHR) related configuration information; identifying at least one PHR based on the PHR related configuration information; and transmitting the at least one PHR, wherein the at least one PHR includes one of a PHR for an actual physical uplink shared channel (PUSCH) associated with a first resource index and a PHR for a reference PUSCH associated with the first resource index, and wherein in the case that a PUSCH associated with the first resource index is transmitted in a slot n, PHR for the actual PUSCH associated with the first resource index is for a first PUSCH associated with the first resource index overlapped with the slot n.
According to an embodiment of the disclosure, a method performed by a base station in a communication system is provided. The method includes transmitting power headroom reporting (PHR) related configuration information; and receiving at least one PHR, wherein the at least one PHR is based on the PHR related configuration information, wherein the at least one PHR includes one of a PHR for an actual physical uplink shared channel (PUSCH) associated with a first resource index and a PHR for a reference PUSCH associated with the first resource index, and wherein in the case that a PUSCH associated with the first resource index is transmitted in a slot n, the PHR for the actual PUSCH associated with the first resource index is for a first PUSCH associated with the first resource index overlapped with the slot n.
According to an embodiment of the disclosure, a terminal of a communication system is provided. The terminal includes a transceiver; and a controller coupled with the transceiver and configured to receive power headroom reporting (PHR) related configuration information, to identify at least one PHR based on the PHR related configuration information, and to transmit the at least one PHR, wherein the at least one PHR includes one of a PHR for an actual physical uplink shared channel (PUSCH) associated with a first resource index and a PHR for a reference PUSCH associated with the first resource index, and wherein in the case that a PUSCH associated with the first resource index is transmitted in a slot n, the PHR for the actual PUSCH associated with the first resource index is for a first PUSCH associated with the first resource index overlapped with the slot n.
According to an embodiment of the disclosure, a base station of a communication system is provided. The base station includes a transceiver; and a controller coupled with the transceiver and configured to transmit power headroom reporting (PHR) related to configuration information, and to receive at least one PHR, wherein the at least one PHR is based on the PHR related configuration information, wherein the at least one PHR includes one of a PHR for an actual physical uplink shared channel (PUSCH) associated with a first resource index and a PHR for a reference PUSCH associated with the first resource index, and wherein in the case that a PUSCH associated with the first resource index is transmitted in a slot n, the PHR for the actual PUSCH associated with the first resource index is for a first PUSCH associated with the first resource index overlapped with the slot n.
According to various embodiments of the disclosure, a method and device capable of effectively providing a service in a mobile communication system are provided.
According to an embodiment of the disclosure, a method of constituting power headroom (PH) information by a terminal supporting multiple transmission and reception point (TRP)-based physical uplink shared channel (PUSCH) transmission is provided.
Effects obtainable in the disclosure are not limited to the above-described effects, and other effects not described will be clearly understood by those of ordinary skill in the art to which the disclosure belongs from the description below.
The above and other objects, features and advantages of the disclosure will become more apparent through the following description of embodiments of the disclosure with reference to the accompanying drawings.
Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.
In describing embodiments, descriptions of technical contents that are well known in the technical field to which the disclosure pertains and that are not directly related to the disclosure will be omitted. This is to more clearly convey the gist of the disclosure without obscuring the gist of the disclosure by omitting unnecessary description.
For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. Further, the size of each component does not fully reflect the actual size. In each drawing, the same reference numerals are given to the same or corresponding components.
Advantages and features of the disclosure, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only embodiments of the disclosure enable the disclosure to be complete, and are provided to fully inform the scope of the disclosure to those of ordinary skill in the art to which the disclosure belongs, and the disclosure is only defined by the scope of the claims. Like reference numerals refer to like components throughout the specification. Further, in describing the disclosure, in the case that it is determined that a detailed description of a related function or constitution may unnecessarily obscure the gist of the disclosure, a detailed description thereof will be omitted. Terms described below are terms defined in consideration of functions in the disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.
Hereinafter, a base station is a subject performing resource allocation of a terminal, and may be at least one of a gNode B, an eNode B, a node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the disclosure, a downlink (DL) is a wireless transmission path of a signal transmitted from a base station to a terminal, and an uplink (UL) is a wireless transmission path of a signal transmitted from a terminal to a base station. Hereinafter, although LTE or LTE-A system may be described as an example, embodiments of the disclosure may be applied to other communication systems having a similar technical background or channel type. For example, 5G mobile communication technology (5G, new radio (NR)) developed after LTE-A may be included therein, and the following 5G may be a concept including existing LTE, LTE-A and other similar services. Further, the disclosure may be applied to other communication systems through some modifications within a range that does not significantly deviate from the scope of the disclosure by the determination of a person having skilled technical knowledge.
In this case, it will be understood that each block of flowcharts and combinations of the flowcharts may be performed by computer program instructions. Because these computer program instructions may be mounted in a processor of a general purpose computer, a special purpose computer, or other programmable data processing equipment, instructions performed by a processor of a computer or other programmable data processing equipment generate a means that performs functions described in the flowchart block(s). Because these computer program instructions may be stored in a computer usable or computer readable memory that may direct a computer or other programmable data processing equipment in order to implement a function in a particular manner, the instructions stored in the computer usable or computer readable memory may produce a production article containing instruction means for performing the function described in the flowchart block(s). Because the computer program instructions may be mounted on a computer or other programmable data processing equipment, a series of operation steps are performed on the computer or other programmable data processing equipment to generate a computer-executed process; thus, instructions for performing the computer or other programmable data processing equipment may provide steps for performing functions described in the flowchart block(s).
Further, each block may represent a portion of a module, a segment, or a code including one or more executable instructions for executing a specified logical function(s). Further, it should be noted that in some alternative implementations, functions recited in the blocks may occur out of order. For example, two blocks illustrated one after another may in fact be performed substantially simultaneously, or the blocks may be sometimes performed in the reverse order according to the corresponding function.
In this case, a term ‘-unit’ used in this embodiment means software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and ‘-unit’ performs certain roles. However, ‘-unit’ is not limited to software or hardware. ‘-unit’ may be constituted to reside in an addressable storage medium or may be constituted to reproduce one or more processors. Therefore, as an example, ‘-unit’ includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuit, data, databases, data structures, tables, arrays, and variables. Functions provided in the components and ‘-units’ may be combined into a smaller number of components and ‘-units’ or may be further separated into additional components and ‘-units’. Further, components and ‘-units’ may be implemented to reproduce one or more CPUs in a device or secure multimedia card. Further, in an embodiment, ‘-unit’ may include one or more processors.
A wireless communication system has evolved from providing voice-oriented services in the early days to a broadband wireless communication system that provides high-speed and high-quality packet data services as in communication standards such as high speed packet access (HSPA), long term evolution (LTE) or evolved universal terrestrial radio access (E-UTRA), LTE-Advanced (LTE-A), and LTE-Pro of 3GPP, high rate packet data (HRPD) and ultra mobile broadband (UMB) of 3GPP2, and IEEE 802.16e.
An LTE system, which is a representative example of the broadband wireless communication system, employs an orthogonal frequency division multiplexing (OFDM) scheme in a downlink (DL) and a single carrier frequency division multiple access (SC-FDMA) scheme in an uplink. The uplink means a radio link in which a user equipment (UE) or a mobile station (MS) transmits data or control signals to an eNode B (eNB) or a base station (BS), and the downlink means a radio link in which a base station transmits data or control signals to a terminal. The above-described multiple access method enables data or control information of each user to distinguish by allocating and operating data or control information so that time-frequency resources to carry data or control information for each user in general do not overlap each other, that is, so that orthogonality is established.
A 5G communication system, which is a future communication system after LTE, should support services that simultaneously satisfy various requirements so that various requirements of users and service providers may be freely reflected. Services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra reliability low latency communication (URLLC), and the like.
The eMBB aims to provide a more improved data rate than a data rate supported by existing LTE, LTE-A, or LTE-Pro. For example, in the 5G communication system, the eMBB should be able to provide a peak data rate of 20 Gbps in a downlink and a peak data rate of 10 Gbps in an uplink from the viewpoint of one base station. Further, the 5G communication system should provide an increased user perceived data rate of a terminal while providing a peak data rate. In order to satisfy such requirements, it is required to improve various transmission and reception technologies, including more advanced multi input and multi output (MIMO) transmission technology. Further, the LTE system transmits a signal using a transmission bandwidth of maximum 20 MHz in the 2 GHz band, whereas the 5G communication system can satisfy a data rate required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in a frequency band of 3 to 6 GHz or 6 GHz or more.
At the same time, mMTC is being considered to support application services such as Internet of Thing (IoT) in the 5G communication system. In order to efficiently provide IoT, nmMTC requires access support for large-scale terminals within a cell, improvement of coverage of terminals, an improved battery time, and cost reduction of terminals. Because the IoT is attached to various sensors and various devices to provide communication functions, it should be able to support a large number of terminals (e.g., 1,000,000 terminals/km2) within a cell. Further, because a terminal supporting mMTC is highly likely to be positioned in a shaded area that a cell cannot cover, such as the basement of a building, due to the nature of the service, the terminal may require wider coverage compared to other services provided by the 5G communication system. The terminal supporting mMTC should be composed of a low cost terminal, and because it is difficult to frequently exchange a battery of the terminal, a very long battery life time such as 10 to 15 years may be required.
Finally, URLLC is a cellular-based wireless communication service used for mission-critical. For example, a service used for remote control of a robot or machinery, industrial automation, unmanned aerial vehicle, remote health care, emergency alert, and the like may be considered. Therefore, communication provided by URLLC should provide very low latency and very high reliability. For example, a service supporting URLLC should satisfy air interface latency smaller than 0.5 milliseconds and simultaneously has the requirement of a packet error rate of 10-5 or less. Therefore, for a service supporting URLLC, the 5G system should provide a transmit time interval (TTI) smaller than that of other services, and at the same time, it may require a design that should allocate a wide resource in a frequency band in order to secure reliability of a communication link.
Three services, i.e., eMBB, URLLC, and mMTC of 5G may be multiplexed and transmitted in a single system. In this case, in order to satisfy different requirements of each service, different transmission and reception techniques and transmission and reception parameters may be used between services. 5G is not limited to the above-described three services.
Hereinafter, a frame structure of a 5G system will be described in more detail with reference to the drawings.
A horizontal axis of
Hereinafter, a bandwidth part (BWP) configuration in a 5G communication system to which the disclosure may be applied will be described in detail with reference to the drawings.
The disclosure is not limited to the above example, and various parameters related to the bandwidth part may be configured to the UE in addition to the configuration information. The information may be transmitted by the base station to the UE through higher layer signaling, for example, RRC signaling. At least one bandwidth part among one or a plurality of configured bandwidth parts may be activated. Whether the configured bandwidth part is activated may be semi-statically transmitted from the base station to the UE through RRC signaling or may be dynamically transmitted from the base station to the UE through downlink control information (DCI).
According to some embodiments, the UE before RRC connection may receive a configuration of an initial BWP for initial access from the base station through a master information block (MIB). More specifically, in an initial access step, the UE may receive configuration information on a search space and a control resource set (CORESET) in which a PDCCH for receiving system information (may correspond to remaining system information (RMSI) or system information block 1 (SIB1)) necessary for initial access may be transmitted through the MIB. The CORESET and search space configured by the MIB may be regarded as an identity (ID) 0, respectively. The base station may notify the UE of configuration information such as frequency allocation information, time allocation information, and numerology for the CORESET #0 through the MIB. Further, the base station may notify the UE of configuration information on a monitoring period and occasion for the CORESET #0, that is, configuration information on a search space #0 through the MIB. The UE may regard a frequency domain configured to the CORESET #0 acquired from the MIB as an initial bandwidth part for initial access. In this case, an identifier (ID) of the initial bandwidth part may be regarded as 0.
The configuration for the bandwidth part supported in the 5G system may be used for various purposes.
According to some embodiments, in the case that a bandwidth supported by the UE is smaller than the system bandwidth, this may be supported through the bandwidth part configuration. For example, as the base station configures a frequency position (configuration information 2) of the bandwidth part to the UE, the UE may transmit and receive data at a specific frequency position within the system bandwidth.
Further, according to some embodiments, for the purpose of supporting different numerologies, the base station may configure a plurality of bandwidth parts to the UE. For example, in order to support both data transmission and reception using subcarrier spacing of 15 kHz and subcarrier spacing of 30 kHz to a certain UE, the base station may configure two bandwidth parts to subcarrier spacings of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency division multiplexed, and in the case that data is to be transmitted and received at specific subcarrier spacing, a bandwidth part configured at corresponding subcarrier spacing may be activated.
Further, according to some embodiments, for the purpose of reducing power consumption of the UE, the base station may configure bandwidth parts having different sizes of bandwidth to the UE. For example, in the case that the UE supports a very large bandwidth, for example, a bandwidth of 100 MHz and always transmits and receives data with the corresponding bandwidth, very large power consumption may occur. In particular, monitoring an unnecessary downlink control channel with a large bandwidth of 100 MHz in a situation in which there is no traffic may be very inefficient in terms of power consumption. For the purpose of reducing power consumption of the UE, the base station may configure a bandwidth part of a relatively small bandwidth, for example, a bandwidth part of 20 MHz to the UE. In a situation in which there is no traffic, the UE may perform a monitoring operation in the bandwidth part of 20 MHz, and in the case that data is generated, the UE may transmit and receive data with the bandwidth part of 100 MHz according to the instruction of the base station.
In a method of configuring the bandwidth part, UEs before RRC connection may receive configuration information on the initial bandwidth part through an MIB in an initial access step. More specifically, the UE may receive a configuration of a control resource set (CORESET) for a downlink control channel in which DCI scheduling the system information block (SIB) may be transmitted from the MIB of a physical broadcast channel (PBCH). A bandwidth of the CORESET configured by the MIB may be regarded as an initial bandwidth part, and the UE may receive a physical downlink shared channel (PDSCH) in which the SIB is transmitted through the configured initial bandwidth part. The initial bandwidth part may be used for other system information (OSI), paging, and random access in addition to the use of receiving the SIB.
[Bandwidth Part (BWP) change]
In the case that one or more bandwidth parts are configured for the UE, the base station may instruct the UE to change (or switch, transition) the bandwidth part using a BWP indicator field in the DCI. For example, in
As described above, because the DCI-based bandwidth part change may be indicated by DCI scheduling the PDSCH or PUSCH, in the case that the UE receives the bandwidth part change request, the UE should receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI in the changed bandwidth part without difficulty. To this end, the standard stipulates the requirements for a delay time (TBWP) required when changing the bandwidth part, and may be defined, for example, as follows.
Note 1:
The requirement for the bandwidth part change delay time supports type 1 or type 2 according to a capability of the UE. The UE may report a supportable bandwidth part delay time type to the base station.
According to the above-mentioned requirement for the bandwidth part change delay time, in the case that the UE receives the DCI including the bandwidth part change indicator in a slot n, the UE may complete the change to a new bandwidth portion indicated by a bandwidth part change indicator at a time point not later than a slot n+TBWP and perform transmission and reception for a data channel scheduled by the corresponding DCI in the changed new bandwidth part. In the case that the base station wants to schedule a data channel with a new bandwidth part, the base station may determine time domain resource allocation for the data channel in consideration of the bandwidth part change delay time (TBWP) of the UE. That is, when scheduling a data channel with a new bandwidth part, in the method of determining time domain resource allocation for the data channel, the base station may schedule the corresponding data channel after the bandwidth part change delay time. Accordingly, the UE may not expect that the DCI indicating the bandwidth part change indicates a slot offset value (K0 or K2) smaller than the bandwidth part change delay time (TBWP).
When the UE receives DCI (e.g., DCI format 1_1 or 0_1) indicating a change in bandwidth part, the UE may not perform any transmission or reception during a corresponding time interval from a third symbol of a slot that receives a PDCCH including the corresponding DCI to a start point of a slot indicated by a slot offset value (K0 or K2) indicated by a time domain resource allocation indicator field in the corresponding DCI. For example, when the UE received DCI indicating a bandwidth part change in a slot n, and a slot offset value indicated by the corresponding DCI is K, the UE may not perform any transmission or reception from a third symbol of the slot n to the previous symbol of a slot n+K (i.e., a last symbol of a slot n+K−1).
Hereinafter, a synchronization signal (SS)/PBCH block in a 5G system to which the disclosure may be applied will be described.
The SS/PBCH block may mean a physical layer channel block composed of a primary SS (PSS), a secondary SS (SSS), and a PBCH. Specifically, it is as follows.
The UE may detect the PSS and SSS in the initial access step and decode the PBCH. The MIB may be acquired from the PBCH, and a control resource set (CORESET) #0 (which may correspond to a CORESET having a CORESET index of 0) may be configured therefrom. The UE may assume that the selected SS/PBCH block and demodulation reference signal (DMRS) transmitted in the CORESET #0 are quasi co-located (QCL) and perform monitoring for the CORESET #0. The UE may receive system information with downlink control information transmitted in the CORESET #0. The UE may acquire random access channel (RACH) related configuration information required for initial access from the received system information. The UE may transmit a physical RACH (PRACH) to the base station in consideration of the selected SS/PBCH index, and the base station that has received the PRACH may acquire information on the SS/PBCH block index selected by the UE. The base station may know that the UE has selected a certain block among SS/PBCH blocks and monitors the CORESET #0 related thereto.
Hereinafter, downlink control information (DCI) in a 5G system to which the present disclosure may be applied will be described in detail.
Scheduling information on uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) in the 5G system is transmitted from the base station to the UE through DCI. The UE may monitor a DCI format for fallback and a DCI format for non-fallback with respect to the PUSCH or PDSCH. The DCI format for fallback may be composed of a fixed field predefined between the base station and the UE, and the DCI format for non-fallback may include a configurable field.
The DCI may be transmitted through a physical downlink control channel (PDCCH) via channel coding and modulation processes. A cyclic redundancy check (CRC) is attached to a DCI message payload, and the CRC may be scrambled with a radio network temporary identifier (RNTI) corresponding to the identity of the UE. Different RNTIs may be used according to the purpose of the DCI message, for example, UE-specific data transmission, power control command, or random access response. That is, the RNTI is not explicitly transmitted but is included in a CRC calculation process and transmitted. Upon receiving the DCI message transmitted on the PDCCH, the UE may identify the CRC using the allocated RNTI, and when the CRC identification result is correct, the UE may know that the corresponding message has been transmitted to the UE.
For example, DCI scheduling a PDSCH for system information (SI) may be scrambled with an SI-RNTI. DCI scheduling a PDSCH for a random access response (RAR) message may be scrambled with an RA-RNTI. DCI scheduling a PDSCH for a paging message may be scrambled with a P-RNTI. DCI notifying a slot format indicator (SFI) may be scrambled with an SFI-RNTI. DCI notifying transmit power control (TPC) may be scrambled with a TPC-RNTI. DCI scheduling a UE-specific PDSCH or PUSCH may be scrambled with a cell RNTI (C-RNTI).
A DCI format 00 may be used as fallback DCI scheduling a PUSCH, and in this case, a CRC may be scrambled with a C-RNTI. The DCI format 0_0 in which a CRC is scrambled with a C-RNTI may include, for example, the following information.
A DCI format 0_1 may be used as non-fallback DCI scheduling a PUSCH, and in this case, a CRC may be scrambled with a C-RNTI. The DCI format 0_1 in which a CRC is scrambled with a C-RNTI may include, for example, the following information.
A DCI format 10 may be used as fallback DCI scheduling a PDSCH, and in this case, a CRC may be scrambled with a C-RNTI. The DCI format 1_0 in which a CRC is scrambled with a C-RNTI may include, for example, the following information.
A DCI format 1_1 may be used as non-fallback DCI scheduling a PDSCH, and in this case, a CRC may be scrambled with a C-RNTI. The DCI format 1_1 in which a CRC is scrambled with a C-RNTI may include, for example, the following information.
In the following description, a downlink control channel in a 5G communication system to which the disclosure may be applied will be described in more detail with reference to the drawings.
The CORESET in the above-described 5G system may be configured by the base station to the UE through higher layer signaling (e.g., system information, master information block (MIB), radio resource control (RRC) signaling). Configuring the CORESET to the UE means providing information such as a CORESET identifier (Identity), a frequency location of the CORESET, and a symbol length of the CORESET. For example, it may include the following information.
In Table 8, tci-StatesPDCCH (simply referred to as a transmission configuration indication (TCI) state) configuration information may include one or a plurality of synchronization signal (SS)/physical broadcast channel (PBCH) block index or channel state information reference signal (CSI-RS) index information in a quasi co located (QCL) relationship with a DMRS transmitted in the corresponding CORESET.
As illustrated in
The basic unit of the downlink control channel illustrated in
The search space may be classified into a common search space and a UE-specific search space. In order to receive cell common control information such as dynamic scheduling for system information or paging messages, a certain group of UEs or all UEs may search for the common search space of the PDCCH. For example, PDSCH scheduling allocation information for transmission of an SIB including cell operator information may be received by searching for the common search space of the PDCCH. In the case of a common search space, because a certain group of UEs or all UEs should receive the PDCCH, the common search space may be defined as a set of pre-promised CCEs. Scheduling allocation information on the UE-specific PDSCH or PUSCH may be received by searching for the UE-specific search space of the PDCCH. The UE-specific search space may be defined UE-specifically as a function of various system parameters and the identity of the UE.
In 5G, a parameter for a search space for a PDCCH may be configured from the base station to the UE through higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station may configure the number of PDCCH candidates at each aggregation level L, a monitoring period for the search space, a monitoring occasion in symbol units within a slot for the search space, a search space type (common search space or UE-specific search space), a combination of a DCI format and a radio network temporary identifier (RNTI) to be monitored in a corresponding search space, and a CORESET index to monitor a search space to the UE. For example, the parameter for the search space for the PDCCH may include the following information.
According to configuration information, the base station may configure one or a plurality of search space sets to the UE. According to some embodiments, the base station may configure a search space set 1 and a search space set 2 to the UE, configure to monitor a DCI format A scrambled with an X-RNTI in the common search space in the search space set 1, and configure to monitor a DCI format B scrambled with a Y-RNTI in the UE-specific search space in the search space set 2.
According to configuration information, one or a plurality of search space sets may exist in a common search space or a UE-specific search space. For example, a search space set #1 and a search space set #2 may be configured to common search spaces, and a search space set #3 and a search space set #4 may be configured to UE-specific search spaces.
In the common search space, a combination of the following DCI format and RNTI may be monitored. The disclosure is not limited to the following examples.
In the UE-specific search space, a combination of the following DCI format and RNTI may be monitored. The disclosure is not limited to the following examples.
The specified RNTIs may follow the following definitions and uses.
C-RNTI (Cell RNTI): Used for scheduling a UE-specific PDSCH
The above-described specified DCI formats may follow the definition below.
A search space of an aggregation level L in a control area p and a search space set s of a 5G wireless communication system (e.g., 5G or NR system) according to an embodiment of the disclosure may be expressed as in Equation 1.
The Yp,n
In the case of a UE-specific search space, the Yp,n
In a 5G wireless communication system (e.g., 5G or NR system) according to an embodiment of the disclosure, as a plurality of search space sets may be configured with different parameters (e.g., parameters in Table 9), a set of search space sets monitored by the UE at each time point may be different. For example, in the case that a search space set #1 is configured to an X-slot period and that a search space set #2 is configured to a Y-slot period and that X and Y are different, the UE may monitor both the search space set #1 and the search space set #2 in a specific slot and monitor one of the search space set #1 and the search space set #2 in a specific slot.
The UE may perform UE capability reporting for the case of having a plurality of PDCCH monitoring positions within a slot for each subcarrier spacing, and in this case, the concept of a span may be used. The span means consecutive symbols in which the UE may monitor a PDCCH within a slot, and each PDCCH monitoring position is within one span. The span may be expressed with (X,Y), where x means the minimum number of symbols that should be separated between first symbols of two consecutive spans, and Y means the number of consecutive symbols that may monitor PDCCH within one span. In this case, the UE may monitor the PDCCH in a section within Y symbols from the first symbol of the span within the span.
With reference to
Slot positions where the above-described common search space and UE-specific search space are located are indicated by a monitoringSymbolsWitninSlot parameter, and symbol positions within the slot are indicated by a bitmap through a monitoringSymbolsWithinSlot parameter of Table 9. A symbol position within a slot in which search space monitoring is possible by the UE may be reported to the base station through the following UE capabilities.
The UE may report whether the above-described UE capability 2 and/or UE capability 3 is(are) supported and related parameters to the base station. The base station may perform time axis resource allocation for a common search space and a UE-specific search space based on the reported UE capabilities. When allocating the resource, the base station may prevent the UE from locating the MO at a position where monitoring is impossible.
In a wireless communication system, one or more different antenna ports (or may be substituted into one or more channels, signals, and combinations thereof, but in the future description of the disclosure, for convenience, will be collectively referred to different antenna ports) may be associated with each other by a quasi co-location (QCL) configuration, as illustrated in Table 14. The TCI state is to notify the QCL relationship between a PDCCH (or PDCCH DMRS) and another RS or channel, and a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed means that the UE is allowed to apply some or all of large-scale channel parameters estimated in the antenna port A to channel measurement from the antenna port B. QCL may need to associate different parameters according to situations such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by a spatial parameter. Accordingly, NR supports four types of QCL relationships, as illustrated in Table 14.
The spatial RX parameter may collectively refer to some or all of various parameters such as angle of arrival (AoA), power angular spectrum (PAS) of AoA, angle of departure (AoD), PAS of AoD, transmit and receive channel correlation, transmit and receive beamforming, and spatial channel correlation.
The QCL relationship may be configured to the UE through the RRC parameter TCI-State and QCL-Info, as illustrated in Table 15. With reference to Table 15, the base station may configure one or more TCI states to the UE and notify the UE of maximum two QCL relationships (qcl-Type1, qcl-Type2) for an RS, that is, the target RS referring to an ID of the TCI state. In this case, each QCL information (QCL-Info) included in each of the TCI states includes a serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, a type and ID of the reference RS, and a QCL type, as illustrated in Table 14.
With reference to
Tables 16 to 20 illustrate valid TCI state configurations according to a type of target antenna port.
Table 16 illustrates valid TCI state configurations in the case that a target antenna port is a CSI-RS for tracking (TRS). The TRS means an NZP CSI-RS in which a repetition parameter is not configured and in which trs-Info is configured to true among CSI-RSs. In the case of a configuration #3 in Table 16, it may be used for aperiodic TRS.
Table 17 illustrates valid TCI state configurations in the case that a target antenna port is a CSI-RS for CSI. The CSI-RS for CSI means an NZP CSI-RS in which a parameter indicating repetition (e.g., repetition parameter) is not configured and in which trs-Info is not configured to true among CSI-RSs.
Table 18 illustrates valid TCI state configurations in the case that a target antenna port is a CSI-RS for beam management (BM, meaning the same as CSI-RS for L1 RSRP reporting). The CSI-RS for BM means an NZP CSI-RS in which a repetition parameter is configured and has a value of On or Off and in which trs-Info is not configured to true among CSI-RSs.
Table 19 illustrates valid TCI state configurations in the case that a target antenna port is a PDCCH DMRS.
Table 20 illustrates valid TCI state configurations in the case that a target antenna port is a PDSCH DMRS.
In a representative QCL configuration method according to Tables 16 to 20, a target antenna port and reference antenna port for each step are configured and operated as in “SSB”->“TRS”->“CSI-RS for CSI, CSI-RS for BM, PDCCH DMRS, or PDSCH DMRS”. Thereby, it is possible to help a reception operation of the UE by linking statistical characteristics measurable from the SSB and TRS to each antenna port.
Specifically, TCI state combinations applicable to the PDCCH DMRS antenna port are illustrated in Table 21. In Table 21, a fourth row is a combination assumed by the UE before RRC is configured, and a configuration after RRC is impossible.
In an embodiment of the disclosure, a wireless communication system (e.g., 5G system or NR system) supports a hierarchical signaling method as illustrated in
With reference to
With reference to
With reference to
The base station may configure one or a plurality of TCI states for a specific control area to the UE, and activate one of the configured TCI states through a MAC CE activation command. For example, {TCI state #0, TCI state #1, TCI state #2} may be configured as TCI states in a control area #1, and the base station may transmit a command activating to assume the TCI state #0 as the TCI state for the control area #1 to the UE through an MAC CE. The UE may accurately receive a DMRS of the corresponding control area based on QCL information in the activated TCI state based on the activation command for the TCI state received through the MAC CE.
For the control area (control area #0) whose index is configured to 0, when the UE does not receive an MAC CE activation command for the TCI state of the control area #0, the UE may assume that the DMRS transmitted from the control area #0 was QCLed with the SS/PBCH block identified in an initial access process or in a non-contention based random access process not triggered by the PDCCH command.
For a control area (control area #X) whose index is configured to a value other than 0, when the UE does not configured with a TCI state for the control area #X or are not configured with one or more TCI states but is not received an MAC CE activation command that activates one of them, the UE may assume that the DMRS transmitted in the control area #X is QCLed with the SS/PBCH block identified in the initial access process.
In the following description, a QCL priority determination operation for the PDCCH will be described in detail.
In the case that the UE operates with carrier aggregation within a single cell or band, while a plurality of control resource sets existing within an activated bandwidth part within a single or a plurality of cells have the same or different QCL-TypeD characteristics in a specific PDCCH monitoring occasion, the plurality of control resource sets overlap in time, the UE may select a specific control resource set according to the QCL priority determination operation and monitor control resource sets having the same QCL-TypeD characteristics as the corresponding control resource set. That is, when a plurality of control resource sets overlap in time, only one QCL-TypeD characteristic may be received. In this case, the criteria for determining the QCL priority may be as follows.
Criterion 1. A control resource set connected to a common search occasion with a lowest index within a cell corresponding to the lowest index among cells including a common search occasion.
Criterion 2. A control resource set connected to a UE-specific search occasion having a lowest index within a cell corresponding to the lowest index among cells including a UE-specific search occasion.
As described above, each of the above criteria applies the next criterion in the case that the criterion is not satisfied. For example, in the case that control resource sets overlap in time in a specific PDCCH monitoring occasion, when all control resource sets are not connected to a common search occasion but connected to a UE-specific search occasion, that is, when the criterion 1 is not satisfied, the UE may omit the application of the criterion 1 and apply the criterion 2.
In the case of selecting a control resource set based on the above-described criteria, the UE may additionally consider the following two items for QCL information configured to the control resource set. First, in the case that a control resource set 1 has a CSI-RS 1 as a reference signal having a QCL-TypeD relationship and that a reference signal having a QCL-TypeD relationship with the CSI-RS 1 is a SSB 1 and that a reference signal having a QCL-TypeD relationship with another control resource set 2 is a SSB 1, the UE may consider that these two control resource sets 1 and 2 have different QCL-TypeD characteristics. Second, in the case that the control resource set 1 has a CSI-RS 1 configured to the cell 1 as a reference signal having a QCL-TypeD relationship and that a reference signal having a QCL-TypeD relationship with the CSI-RS 1 is a SSB 1 and that the control resource set 2 has a CSI-RS 2 configured to the cell 2 as a reference signal having a QCL-TypeD relationship and that a reference signal having a QCL-TypeD relationship with the CSI-RS 2 is the same SSB 1, the UE may consider that two control resource sets have the same QCL-TypeD characteristics.
For example, the UE may be configured to receive a plurality of control resource sets overlapping in time in a specific PDCCH monitoring occasion 1110, and the plurality of control resource sets may be connected to a common search space or a UE-specific search space for a plurality of cells. Within the corresponding PDCCH monitoring occasion, a COREST #1, 1115 connected to the first common search occasion may exist in a BWP #1, 1100 of a cell #1, and a COREST #1, 1120 connected to the first common search occasion and a COREST #2, 1125 connected to the second UE-specific search occasion may exist in a BWP #1, 1105 of a cell #2. The control resource set 1115 may have a QCL-TypeD relationship with a first CSI-RS resource configured within the BWP #1 of the cell #1, and the COREST #2, 1125 may have a QCL-TypeD relationship with a first CSI-RS resource configured within the BWP #1 of the cell #2. Therefore, when a criterion 1 is applied to the corresponding PDCCH monitoring occasion 1110, all other control resource sets having the same QCL-TypeD reference signal as the COREST #1, 1115 may be received. Therefore, the UE may receive the CORESTs 1115 and 1120 in the corresponding PDCCH monitoring occasion 1110. As another example, the UE may be configured to receive a plurality of control resource sets overlapping in time in a specific PDCCH monitoring occasion 1140, and the plurality of control resource sets may be connected to a common search space or a UE-specific search space for a plurality of cells. Within the corresponding PDCCH monitoring occasion, a COREST #1, 1145 connected to a specific search occasion of the first UE and a COREST #2, 1150 connected to a specific search occasion of the second UE may exist within a BWP #1, 1130 of the cell #1, and a COREST #1, 1155 connected to the first UE-specific search occasion and a COREST #2, 1160 connected to a third UE-specific search occasion may exist within the BWP #1, 1135 of the cell #2. The CORESTs 1145 and 1150 may have a QCL-TypeD relationship with a first CSI-RS resource configured within the BWP #1 of the cell #1, and the COREST #1, 1155 may have a QCL-TypeD relationship with a first CSI-RS resource configured within the BWP #1 of the cell #2, and the COREST #2, 1160 may have a QCL-TypeD relationship with the second CSI-RS resource configured in the BWP #1 of the cell #2. However, when the criterion 1 is applied to the corresponding PDCCH monitoring occasion 1140, there is no common search occasion; thus, a criterion 2, which is the next criterion may be applied. When the criterion 2 is applied to the corresponding PDCCH monitoring occasion 1140, all other control resource sets having the same QCL-TypeD reference signal as the control resource set 1145 may be received. Therefore, the UE may receive the control resource sets 1145 and 1150 in the corresponding PDCCH monitoring occasion 1140.
In the following description, a rate matching operation and a puncturing operation will be described in detail.
In the case that a time and frequency resource A to transmit a random symbol sequence A overlaps with a random time and frequency resource B, a rate matching or puncturing operation may be considered by a transmitting and receiving operation of a channel A considering an area resource C in which the resource A and the resource B overlap. A specific operation thereof may follow the following description.
In the following description, a method of configuring rate matching resources for the purpose of rate matching in the 5G communication system will be described. Rate matching means that a magnitude of a signal is adjusted in consideration of an amount of resources capable of transmitting the signal. For example, rate matching of data channels may mean that a magnitude of data is adjusted accordingly without mapping and transmitting data channels for specific time and frequency resource domains.
The base station may dynamically notify the UE through DCI whether to rate match the data channel in the configured rate matching resource portion through additional configuration (corresponding to the “rate matching indicator” in the above-described DCI format). Specifically, the base station may select some of the configured rate matching resources and group them into rate matching resource groups, and indicate the UE whether rate matching of a data channel for each rate matching resource group with DCI using a bitmap method. For example, in the case that four rate matching resources, RMR #1, RMR #2, RMR #3, and RMR #4 are configured, the base station may configure RMG #1={RMR #1, RMR #2}, RMG #2={RMR #3, RMR #4} as a rate matching group, and instruct whether rate matching in the RMG #1 and RMG #2 to the UE with a bitmap using 2 bits in the DCI field. For example, “1” may be indicated in the case that rate matching is to be performed, and “0” may be indicated in the case that rate matching is not to be performed.
In the 5G system to which the disclosure may be applied, granularity of “RB symbol level” and “RE level” is supported with a method of configuring the above-described rate matching resources to the UE. More specifically, the following configuration method may be followed.
The UE may receive a configuration of maximum four RateMatchPatterns for each bandwidth part by higher layer signaling, and one RateMatchPattern may include the following contents.
A reserved resource in the bandwidth part may include a resource in which time and frequency resource domains of the corresponding reserved resource are configured in a combination of an RB level bitmap and a symbol level bitmap on the frequency axis. The reserve resource may span one or two slots. A time domain pattern (periodicityAndPattern) in which time and frequency domains composed of each RB level and symbol level bitmap pair are repeated may be additionally configured.
The reserved resource in the bandwidth part may include time and frequency domain resource domains configured with control resource sets within the bandwidth part and resource domains corresponding to time domain patterns configured with search space configurations in which the corresponding resource domains are repeated.
[RE level]
The UE may receive the following contents through higher layer signaling.
Configuration information (lte-CRS-ToMatchAround) for the RE corresponding to an LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern may include the number of LTE CRS ports (nrofCRS-Ports), an LTE-CRS-vshift(s) value (v-shift), LTE carrier center subcarrier location information (carrierFreqDL) from a frequency point (e.g., reference point A) to be the reference, LTE carrier bandwidth size (carrierBandwidthDL) information, and subframe configuration information (mbsfn-SubframeConfigList) corresponding to a multicast-broadcast single-frequency network (MBSFN). The UE may determine a position of the CRS in the NR slot corresponding to the LTE subframe based on the above information.
Configuration information (lte-CRS-ToMatchAround) for the RE may include configuration information on a resource set corresponding to one or a plurality of zero power (ZP) CSI-RS in the bandwidth part.
Hereinafter, a rate match process for the above-described LTE CRS will be described in detail. For coexistence of Long Term Evolution (LTE) and New RAT (NR) (LTE-NR Coexistence), NR provides a function of configuring a cell specific reference signal (CRS) pattern of LTE to an NR UE. More specifically, the CRS pattern may be provided by RRC signaling including at least one parameter in a ServingCellConfig Information Element (IE) or a ServingCellConfigCommon IE. The parameters may include, for example, lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, crs-RateMatch-PerCORESETPoolIndex-r16, and the like.
Rel-15 NR provides a function of configuring one CRS pattern per serving cell through the lte-CRS-ToMatchAround parameter. In Rel-16 NR, the above function has been extended to configure a plurality of CRS patterns per serving cell. More specifically, one CRS pattern per LTE carrier may be configured in a single-transmission and reception point (TRP) configuration UE, and two CRS patterns per LTE carrier may be configured in a multi-TRP configuration UE. For example, maximum three CRS patterns per serving cell may be configured in a single-TRP configuration UE through an lte-CRS-PatternList1-r16 parameter. For another example, a CRS for each TRP may be configured in a multi-TRP configuration UE. That is, a CRS pattern for a TRP1 may be configured through the lte-CRS-PatternList1-r16 parameter, and a CRS pattern for a TRP2 may be configured through the lte-CRS-PatternList2-r16 parameter. In the case that two TRPs are configured as described above, it is determined through the crs-RateMatch-PerCORESETPoolIndex-r16 parameter whether both CRS patterns of the TRP1 and the TRP2 are applied or whether only the CRS pattern for one TRP is applied to a specific physical downlink shared channel (PDSCH), and when the crs-RateMatch-PerCORESETPoolIndex-r16 parameter is configured to enabled, only a CRS pattern of one TRP is applied, and in other cases, all CRS patterns of two TRPs are applied.
Table 22 illustrates a ServingCellConfig IE including the CRS pattern, and Table 23 illustrates a RateMatchPattemLTE-CRS IE including at least one parameter for the CRS pattern.
Hereinafter, a PDSCH processing procedure time will be described. In the case that the base station schedules the UE to transmit a PDSCH using a DCI format 1_0, 1_1, or 1_2, the UE applies a transmission method (modulation and demodulation and coding instruction index (MCS), demodulation reference signal related information, time and frequency resource allocation information, and the like) indicated through DCI; thus, a PDSCH processing time for receiving a PDSCH may be required. In NR, the PDSCH processing time was defined in consideration of this. The PDSCH processing time of the UE may follow Equation 2.
T
proc,1=(N1+d1,1+d2)(2048+144)κ2−μTc+Text Equation 2
In Tproc,1 described above with Equation 2, each variable may have the following meaning.
When a position of a first uplink transmission symbol of a PUCCH including HARQ-ACK information (the corresponding position is K1 defined as a transmission time point of HARQ-ACK, a PUCCH resource used for HARQ-ACK transmission, and the timing advance effect may be considered) does not start earlier than a first uplink transmission symbol that appears after a time of Tproc,1 from a last symbol of the PDSCH, the UE should transmit a valid HARQ-ACK message. That is, the UE should transmit the PUCCH including a HARQ-ACK only in the case that a PDSCH processing time is sufficient. Otherwise, the UE may not provide valid HARQ-ACK information corresponding to the scheduled PDSCH to the base station. The Tproc,1 may be used to both general and extended CP cases. In the case of a PDSCH composed of two PDSCH transmission positions within one slot, d1,1 is calculated based on a first PDSCH transmission position within the corresponding slot.
Hereinafter, in the case of cross-carrier scheduling in which PDCCH, which is numerology in which the scheduling PDCCH is transmitted, and PDSCH which is numerology in which a PDSCH scheduled through the corresponding PDCCH is transmitted, are different, Npdsch, which is a PDSCH reception preparation time of the UE defined for a time interval between the PDCCH and the PDSCH will be described.
In the case of μPDCCH<μPDSCH, the scheduled PDSCH may not be transmitted earlier than a first symbol of a slot appearing after an Npdsch symbol from a last symbol of a PDCCH that schedules the corresponding PDSCH. A transmission symbol of the corresponding PDSCH may include a DM-RS.
In the case of μPDCCH>μPDSCH, the scheduled PDSCH may be transmitted after an Npdsch symbol from a last symbol of a PDCCH that schedules the corresponding PDSCH. A transmission symbol of the corresponding PDSCH may include a DM-RS.
Npdsch according to the scheduled PDCCH subcarrier spacing may be the same as that illustrated in Table 26.
Hereinafter, a method of estimating an uplink channel using sounding reference signal (SRS) transmission of the UE will be described. In order to transmit configuration information for SRS transmission to the UE, the base station may configure at least one SRS configuration for each uplink BWP, and configure at least one SRS resource set for each SRS configuration. As an example, in order to transmit information on the SRS resource set, the base station and the UE may send and receive higher-layer signaling information as follows.
The UE may understand that the SRS resource included in the set of SRS resource indexes referenced in the SRS resource set follows information configured to the SRS resource set.
Further, in order to transmit individual configuration information on the SRS resource, the base station and the UE may transmit and receive higher layer signaling information. As an example, individual configuration information on the SRS resource may include time-frequency axis mapping information within a slot of the SRS resource, which may include information on frequency hopping within a slot or between slots of the SRS resource. Further, individual configuration information on the SRS resource may include a time axis transmission configuration of the SRS resource, and be configured to one of ‘periodic’, ‘semi-persistent’, and ‘aperiodic’. This may be limited to have the same time axis transmission configuration as that of an SRS resource set including an SRS resource. In the case that a time axis transmission configuration of the SRS resource is configured to ‘periodic’ or ‘semi-persistent’, an SRS resource transmission period and slot offset (e.g., periodicityAndOffset) may be additionally included in the time axis transmission configuration.
The base station may activate, deactivate, or trigger SRS transmission to the UE through higher layer signaling including RRC signaling or MAC CE signaling, or L1 signaling (e.g., DCI). For example, the base station may activate or deactivate periodic SRS transmission through higher layer signaling to the UE. The base station may instruct to activate an SRS resource set in which a resourceType is configured to periodic through higher layer signaling, and the UE may transmit a referring SRS resource in the activated SRS resource set. Time-frequency axis resource mapping within a slot of the transmitting SRS resource follows resource mapping information configured to the SRS resource, and slot mapping including a transmission period and slot offset follows periodicityAndOffset configured to the SRS resource. Further, a spatial domain transmission filter applied to the transmitting SRS resource may refer to spatial relation info configured to the SRS resource or associated CSI-RS information configured to the SRS resource set including the SRS resource. The UE may transmit an SRS resource within the activated uplink BWP for a periodic SRS resource activated through higher layer signaling.
For example, the base station may activate or deactivate semi-persistent SRS transmission to the UE through higher layer signaling. The base station may instruct to activate the SRS resource set through MAC CE signaling, and the UE may transmit an SRS resource referenced in the activated SRS resource set. An SRS resource set activated through MAC CE signaling may be limited to an SRS resource set whose resourceType is configured to semi-persistent. Time-frequency axis resource mapping within a slot of the transmitting SRS resource follows resource mapping information configured to the SRS resource, and slot mapping including a transmission period and slot offset follows periodicityAndOffset configured to the SRS resource. Further, a spatial domain transmission filter applied to the transmitting SRS resource may refer to spatial relation info configured to the SRS resource or associated CSI-RS information configured to the SRS resource set including the SRS resource. In the case that spatial relation info is configured to the SRS resource, a spatial domain transmission filter may be determined with reference to configuration information on spatial relation info transmitted through MAC CE signaling activating semi-persistent SRS transmission instead of following it. The UE may transmit an SRS resource within an activated uplink BWP for a semi-persistent SRS resource activated through higher layer signaling.
For example, the base station may trigger aperiodic SRS transmission to the UE through DCI. The base station may indicate one of aperiodic SRS resource triggers (aperiodicSRS-ResourceTrigger) through an SRS request field of DCI. The UE may understand that the SRS resource set including the aperiodic SRS resource trigger indicated through DCI in an aperiodic SRS resource trigger list among configuration information of the SRS resource set has been triggered. The UE may transmit a referring SRS resource in the triggered SRS resource set. Time-frequency axis resource mapping within a slot of the transmitting SRS resource follows resource mapping information configured to the SRS resource. Further, slot mapping of the transmitting SRS resource may be determined through a slot offset between a PDCCH including DCI and an SRS resource, which may refer to a value(s) included in a slot offset set configured to the SRS resource set. Specifically, the slot offset between the PDCCH including DCI and the SRS resource may apply a value indicated in a time domain resource assignment field of DCI among offset value(s) included in the slot offset set configured to the SRS resource set. Further, a spatial domain transmission filter applied to the transmitting SRS resource may refer to spatial relation info configured to the SRS resource or associated CSI-RS information configured to the SRS resource set including the SRS resource. The UE may transmit an SRS resource within an activated uplink BWP for an aperiodic SRS resource triggered through DCI.
In the case that the base station triggers aperiodic SRS transmission to the UE through DCI, in order for the UE to transmit an SRS by applying configuration information on the SRS resource, a minimum time interval between a PDCCH including DCI triggering aperiodic SRS transmission and a transmitting SRS may be required. A time interval for SRS transmission of the UE may be defined as the number of symbols between a last symbol of a PDCCH including DCI triggering aperiodic SRS transmission and a first symbol to which a first transmitted SRS resource among transmitting SRS resource(s) is mapped. The minimum time interval may be determined with reference to a PUSCH preparation procedure time required for the UE to prepare for PUSCH transmission. Further, the minimum time interval may have a different value according to where an SRS resource set including a transmitting SRS resource is used. For example, the minimum time interval may be determined to an N2 symbol defined in consideration of a UE processing capability according to the capability of the UE with reference to the PUSCH preparation procedure time of the UE. Further, in the case that the usage of the SRS resource set is configured to ‘codebook’ or ‘antennaSwitching’ in consideration of the usage of the SRS resource set including the transmitting SRS resource, the minimum time interval is determined to N2 symbol, and in the case that the usage of the SRS resource set is configured to ‘nonCodebook’ or ‘beamManagement’, the minimum time interval may be determined to N2+14 symbols. The UE may transmit an aperiodic SRS in the case that a time interval for aperiodic SRS transmission is greater than or equal to the minimum time interval, and ignore DCI triggering an aperiodic SRS in the case that a time interval for aperiodic SRS transmission is smaller than the minimum time interval.
The spatialRelationInfo configuration information in Table 27 applies beam information of the reference signal to the beam used for the corresponding SRS transmission with reference to one reference signal. For example, the configuration of spatialRelationInfo may include information such as Table 28.
With reference to the spatialRelationInfo configuration, an SS/PBCH block index, CSI-RS index, or SRS index may be configured as an index of a reference signal to be referred in order to use beam information of a specific reference signal. A higher-layer signaling referenceSignal is configuration information indicating beam information of which reference signal is referred to for transmission of the corresponding SRS, an ssb-Index means an index of the SS/PBCH block, a csi-RS-Index means an index of the CSI-RS, and an srs means an index of the SRS. When a value of a higher-layer signaling referenceSignal is configured to an ‘ssb-Index’, the UE may apply a receiving beam used when receiving the SS/PBCH block corresponding to the ssb-Index as a transmitting beam of the corresponding SRS transmission. When a value of higher-layer signaling referenceSignal is configured to a ‘csi-RS-Index’, the UE may apply a receiving beam used when receiving the CSI-RS corresponding to the csi-RS-Index as a transmitting beam of the corresponding SRS transmission. When a value of a higher-layer signaling referenceSignal is configured to the ‘srs’, the UE may apply a transmission beam used when transmitting an SRS corresponding to the srs as a transmission beam of the corresponding SRS transmission.
Hereinafter, a scheduling method of PUSCH transmission will be described. PUSCH transmission may be dynamically scheduled by a UL grant in DCI or may be operated by a configured grant Type 1 or Type 2. Dynamic scheduling indication for PUSCH transmission is available in a DCI format 0_0 or 0_1.
Configured grant Type 1 PUSCH transmission may be semi-statically configured through reception of configuredGrantConfig including rrc-ConfiguredUplinkGrant in Table 29 through higher-layer signaling without reception of the UL grant in DCI. Configured grant type 2 PUSCH transmission may be scheduled semi-persistently by UL grant in DCI after receiving configuredGrantConfig not including rrc-ConfiguredUplinkGrant in Table 29 through higher-layer signaling. In the case that PUSCH transmission operates by a configured grant, parameters applied to PUSCH transmission are applied through configuredGrantConfig, which is higher-layer signaling of Table 29 except for dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling of UCI-OnPUSCH provided by a push-Config of Table 30, which is higher-layer signaling. When the UE is provided with a transformPrecoder in a configuredGrantConfig, which is higher-layer signaling of Table 29, the UE applies tp-pi2BPSK in a push-Config of Table 29 to PUSCH transmission operating by the configured grant.
Hereinafter, a PUSCH transmission method will be described. A DMRS antenna port for PUSCH transmission is the same as an antenna port for SRS transmission. PUSCH transmission may follow a codebook-based transmission method and a non-codebook-based transmission method, respectively, according to whether a value of txConfig in a push-Config of Table 30, which is higher-layer signaling is ‘codebook’ or ‘nonCodebook’.
As described above, PUSCH transmission may be dynamically scheduled through a DCI format 0_0 or 0_1, and be semi-statically configured by configured grant. When the UE is instructed to schedule PUSCH transmission through a DCI format 0_0, the UE performs a beam configuration for PUSCH transmission using a pucch-spatialRelationInfoID corresponding to an UE-specific PUCCH resource corresponding to the minimum ID within the activated uplink BWP in the serving cell, and in this case, PUSCH transmission is based on a single antenna port. The UE does not expect scheduling for PUSCH transmission through a DCI format 0_0 in BWP in which a PUCCH resource including pucch-spatialRelationlnfo is not configured. When the UE is not configured with txConfig in push-Config of Table 30, the UE does not expect to be scheduled in a DCI format 0_1.
Hereinafter, codebook-based PUSCH transmission will be described. Codebook-based PUSCH transmission may be dynamically scheduled through a DCI format 0_0 or 0_1, and operate quasi-statically by configured grant. When the codebook-based PUSCH is dynamically scheduled by a DCI format 0_1 or quasi-statically configured by a configured grant, the UE determines a precoder for PUSCH transmission based on a SRS resource indicator (SRI), transmission precoding matrix indicator (TPMI), and transmission rank (PUSCH transmission layer number).
In this case, the SRI may be given through a field SRS resource indicator in DCI or may be configured through an srs-ResourceIndicator, which is higher-layer signaling. When transmitting a codebook-based PUSCH, the UE may be configured with at least one SRS resource, and be configured with maximum two SRS resources. In the case that the UE receives the SRI through DCI, the SRS resource indicated by the corresponding SRI means an SRS resource corresponding to the SRI among SRS resources transmitted earlier than the PDCCH including the corresponding SRI. Further, TPMI and transmission rank may be given through a field precoding information and number of layers in DCI or may be configured through precodingAndNumberOfLayers, which is higher-layer signaling. The TPMI is used for indicating a precoder applied to PUSCH transmission. When the UE is configured with one SRS resource, the TPMI is used for indicating a precoder to be applied in the configured one SRS resource. When the UE is configured with a plurality of SRS resources, the TPMI is used for indicating a precoder to be applied in the SRS resource indicated through the SRI.
A precoder to be used for PUSCH transmission is selected from an uplink codebook having the same number of antenna ports as a value of nrofSRS-Ports in SRS-Config, which is higher-layer signaling. In codebook-based PUSCH transmission, the UE determines a codebook subset based on TPMI and codebookSubset in push-Config, which is higher-layer signaling. CodebookSubset in push-Config, which is higher-layer signaling may be configured to one of ‘fullyAndPartialAndNonCoherent’, ‘partialAndNonCoherent’, or ‘nonCoherent’ based on the UE capability reported by the UE to the base station. When the UE reported ‘partialAndNonCoherent’ with the UE capability, the UE does not expect that a value of codebookSubset, which is higher-layer signaling is configured to ‘fullyAndPartialAndNonCoherent’. Further, when the UE reported ‘nonCoherent’ with the UE capability, the UE does not expect that a value of codebookSubset, which is higher-layer signaling is configured to ‘fullyAndPartialAndNonCoherent’ or ‘partialAndNonCoherent’. In the case that nrofSRS-Ports in SRS-ResourceSet, which is higher-layer signaling indicates two SRS antenna ports, the UE does not expect that a value of codebookSubset, which is higher-layer signaling is configured to ‘partialAndNonCoherent’.
The UE may be configured with one SRS resource set in which a value of usage in the SRS-ResourceSet, which is higher-layer signaling is configured to ‘codebook’, and one SRS resource in the corresponding SRS resource set may be indicated through the SRI. When several SRS resources are configured in an SRS resource set in which a usage value in SRS-ResourceSet, which is higher-layer signaling is configured to ‘codebook’, the UE expects that a value of nrofSRS-Ports in the SRS-Resource, which is higher-layer signaling is configured to the same value for all SRS resources.
The UE transmits one or a plurality of SRS resources included in an SRS resource set in which a value of usage is configured to ‘codebook’ to the base station according to higher-layer signaling, and the base station selects one of SRS resources transmitted by the UE to instruct the UE to perform PUSCH transmission using transmission beam information of the SRS resource. In this case, in codebook-based PUSCH transmission, the SRI is used as information for selecting an index of one SRS resource and is included in DCI. Additionally, the base station includes information indicating the TPMI and rank to be used by the UE for PUSCH transmission in the DCI. The UE applies a rank indicated based on a transmission beam of the corresponding SRS resource and a precoder indicated by the TPMI to perform PUSCH transmission using the SRS resource indicated by the SRI.
Hereinafter, non-codebook based PUSCH transmission will be described. Non-codebook based PUSCH transmission may be dynamically scheduled through a DCI format 0_0 or 0_1, and operate quasi-statically by a configured grant. In the case that at least one SRS resource is configured in an SRS resource set in which a value of usage in the SRS-ResourceSet, which is higher-layer signaling is configured to ‘nonCodebook’, the UE may receive scheduling of non-codebook based PUSCH transmission through a DCI format 0_1.
For an SRS resource set in which a value of usage in the SRS-ResourceSet, which is higher-layer signaling is configured to ‘nonCodebook’, the UE may be configured with one connected non-zero power CSI-RS (NZP CSI-RS) resource. The UE may calculate a precoder for SRS transmission through measurement of an NZP CSI-RS resource connected to the SRS resource set. When the difference between a last reception symbol of an aperiodic NZP CSI-RS resource connected to the SRS resource set and a first symbol of aperiodic SRS transmission in the UE is smaller than 42 symbols, the UE does not expect that information on the precoder for SRS transmission is updated.
When a value of resourceType in SRS-ResourceSet, which is higher-layer signaling is configured to ‘aperiodic’, the connected NZP CSI-RS is indicated by an SRS request, which is a field in a DCI format 0_1 or 1_1. In this case, when the connected NZP CSI-RS resource is an aperiodic NZP CSI-RS resource, it indicates that the connected NZP CSI-RS exists in the case that a value of a field SRS request in a DCI format 0_1 or 1_1 is not ‘00’. In this case, the corresponding DCI should not indicate cross carrier or cross BWP scheduling. Further, when a value of the SRS request indicates existence of the NZP CSI-RS, the corresponding NZP CSI-RS is located in a slot in which the PDCCH including the SRS request field is transmitted. In this case, TCI states configured to the scheduled subcarriers are not configured to QCL-TypeD.
When a periodic or semi-persistent SRS resource set is configured, the connected NZP CSI-RS may be indicated through associatedCSI-RS in an SRS-ResourceSet, which is higher-layer signaling. For non-codebook based transmission, the UE does not expect that spatialRelationInfo, which is higher-layer signaling for an SRS resource and associatedCSI-RS in SRS-ResourceSet, which is higher-layer signaling are configured together.
In the case that the UE are configured with a plurality of SRS resources, the UE may determine a precoder and transmission rank to be applied to PUSCH transmission based on the SRI instructed by the base station. In this case, the SRI may be indicated through a field SRS resource indicator in DCI or may be configured through a srs-ResourceIndicator, which is higher-layer signaling. Similar to the above-described codebook-based PUSCH transmission, in the case that the UE receives an SRI through DCI, the SRS resource indicated by the corresponding SRI means the SRS resource corresponding to the SRI among SRS resources transmitted earlier than the PDCCH including the corresponding SRI. The UE may use one or a plurality of SRS resources for SRS transmission, and the number of maximum SRS resources that may be simultaneously transmitted in the same symbol within one SRS resource set and the number of maximum SRS resources are determined by an UE capability reporting by the UE to the base station. In this case, SRS resources transmitted simultaneously by the UE occupy the same RB. The UE configures one SRS port for each SRS resource. A SRS resource set in which a value of usage in the SRS-ResourceSet, which is higher-layer signaling is configured to ‘nonCodebook’ may be configured to only one, and SRS resources for non-codebook based PUSCH transmission may be configured to maximum four.
The base station transmits one NZP-CSI-RS connected to the SRS resource set to the UE, and the UE calculates a precoder to use when transmitting one or a plurality of SRS resources in the corresponding SRS resource set based on the measurement result upon receiving the corresponding NZP-CSI-RS. The UE applies the calculated precoder when transmitting one or a plurality of SRS resources in the SRS resource set in which the usage is configured to ‘nonCodebook’ to the base station, and the base station selects one or a plurality of SRS resources among one or a plurality of received SRS resources. In this case, in non-codebook based PUSCH transmission, the SRI indicates an index capable of expressing a combination of one or a plurality of SRS resources, and the SRI is included in DCI. In this case, the number of SRS resources indicated by the SRI transmitted by the base station may be the number of transmission layers of the PUSCH, and the UE applies a precoder applied to transmission of the SRS resource to each layer to transmit the PUSCH.
Hereinafter, a PUSCH preparation procedure time will be described. In the case that the base station schedules the UE to transmit a PUSCH using a DCI format 0_0, 0_1, or 0_2, the UE may apply a transmission method (transmission precoding method of SRS resource, number of transmission layers, spatial domain transmission filter) indicated through DCI to require a PUSCH preparation procedure time for transmitting the PUSCH. NR defined a PUSCH preparation procedure time considering this. The PUSCH preparation procedure time of the UE may follow Equation 3.
T
proc,2=max((N2+d2,1+d2)(2048+144)κ2−μTc+Text+Tswitch,d2,2) Equation 3
In Tproc,2 described above with Equation 3, each variable may have the following meaning.
When the base station and the UE consider time axis resource mapping information of a PUSCH scheduled through DCI and the effect of timing advance between the uplink and downlink, in the case that a first symbol of a PUSCH starts earlier than a first uplink symbol in which the CP starts after Tproc,2 from a last symbol of the PDCCH including DCI that schedules the PUSCH, the base station and the UE determine that a PUSCH preparation procedure time is not sufficient. When not, the base station and the UE determine that the PUSCH preparation procedure time is sufficient. The UE may transmit the PUSCH only in the case that the PUSCH preparation procedure time is sufficient, and ignore DCI scheduling the PUSCH in the case that the PUSCH preparation procedure time is not sufficient.
In the following description, repetition transmission of an uplink data channel in a 5G system to which the disclosure may be applied will be described in detail. The 5G system supports two types, a PUSCH repetition transmission type A and a PUSCH repetition transmission type B with a repetition transmission method of an uplink data channel. The UE may be configured with either PUSCH repetition transmission type A or B through higher layer signaling.
As described above, a symbol length of an uplink data channel and a location of a start symbol are determined by a time domain resource allocation method within one slot, and the base station may notify the UE of the number of repetition transmissions through higher layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).
The UE may repeatedly transmit an uplink data channel in which a length and start symbol of a configured uplink data channel are the same in consecutive slots based on the number of repetition transmissions received from the base station. In this case, in the case that a slot configured by the base station to the UE as downlink or at least one symbol of symbols of an uplink data channel configured by the UE is configured to a downlink, the UE skips transmission of the uplink data channel, but the number of repetition transmissions of the uplink data channel is counted.
As described above, a start symbol and length of an uplink data channel are determined by a time domain resource allocation method within one slot, and the base station may notify the UE of the number numberofrepetitions of repetition transmissions through higher-layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).
First, nominal repetition of the uplink data channel is determined based on a start symbol and length of the configured uplink data channel as follows. A slot in which the nth nominal repetition starts is given by
and a symbol starting in the slot is given by mod (S+n·L,Nsymbslot). A slot in which the nth nominal repetition ends is given by
and a symbol ending in the slot is given by mod(S+(n+1)·L−1,Nsymbslot). Here, n=0, . . . , numberofrepetitions−1, S denotes a start symbol of the configured uplink data channel, and L denotes a symbol length of the configured uplink data channel. Ks denotes a slot in which PUSCH transmission starts, and Nsymbslot denotes the number of symbols per slot.
The UE determines an invalid symbol for the PUSCH repetition transmission type B. A symbol configured to a downlink by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated is determined as an invalid symbol for the PUSCH repetition transmission type B. Additionally, an invalid symbol may be configured in a higher layer parameter (e.g., InvalidSymbolPattern). A higher layer parameter (e.g., InvalidSymbolPattern) provides a symbol level bitmap over one slot or two slots; thus, invalid symbols may be configured. 1 in the bitmap represents an invalid symbol. Additionally, a period and pattern of the bitmap may be configured through a higher layer parameter (e.g., periodicityAndPattern). When a higher layer parameter (e.g., InvalidSymbolPattern) is configured and the InvalidSymbolPatternIndicator-ForDCIFormat0_1 or InvalidSymbolPatternIndicator-ForDCIFormat0_2 parameter indicates 1, the UE applies an invalid symbol pattern, and when the parameter indicates 0, the UE does not apply an invalid symbol pattern. When a higher layer parameter (e.g., InvalidSymbolPattern) is configured and the InvalidSymbolPatternIndicator-ForDCIFormat0_1 or InvalidSymbolPatternIndicator-ForDCIFormat0_2 parameter is not configured, the UE applies an invalid symbol pattern.
After an invalid symbol is determined, for each nominal repetition, the UE may consider symbols other than the invalid symbol as valid symbols. When one or more valid symbols are included in each nominal repetition, the nominal repetition may include one or more actual repetitions. Here, each actual repetition includes a continuous set of valid symbols that may be used for the PUSCH repetition transmission type B in one slot.
For example, the UE may receive a configuration of a start symbol S of an uplink data channel to 0, a length L of an uplink data channel to 14, and the number of repetition transmissions to 16. In this case, nominal repetition is appeared in 16 consecutive slots (1301). Thereafter, the UE may determine a symbol configured to a downlink symbol in each nominal repetition 1301 as an invalid symbol. Further, the UE determines symbols configured to 1 in an invalid symbol pattern 1302 as invalid symbols. In each nominal repetition, in the case that valid symbols, not invalid symbols, are composed of one or more consecutive symbols in one slot, the valid symbols are configured to actual repetitions and transmitted (1303).
Further, for PUSCH repetition transmission, NR Release 16 may define the following additional methods for UL grant-based PUSCH transmission and configured grant-based PUSCH transmission across slot boundaries.
In the following description, frequency hopping of a physical uplink shared channel (PUSCH) in a 5G system to which the disclosure may be applied will be described in detail.
In 5G, as a frequency hopping method of an uplink data channel, two methods are supported for each PUSCH repetition transmission type. First, a PUSCH repetition transmission type A supports intra-slot frequency hopping and inter-slot frequency hopping, and a PUSCH repetition transmission type B supports inter-repetition frequency hopping and inter-slot frequency hopping.
An intra-slot frequency hopping method supported in the PUSCH repetition transmission type A is a method in which the UE changes and transmits allocated resources of a frequency domain by configured frequency offset in two hops within one slot. In intra-slot frequency hopping, a starting RB of each hop may be represented through Equation 4.
In Equation 4, i=0 and i=1 denote the first hop and the second hop, respectively, RBstart denotes a starting RB in UL BWP and is calculated from a frequency resource allocation method. Roffset represents a frequency offset between two hops through a higher layer parameter. The number of symbols of the first hop may be represented by └NsymbPUSCH,s/2┘, and the number of symbols of the second hop may be represented by NsymbPUSCH,s−└NsymbPUSCH,s/2┘. NsymbPUSCH,s is a length of PUSCH transmission within one slot and is represented by the number of OFDM symbols.
Hereinafter, an inter-slot frequency hopping method supported in PUSCH repetition transmission types A and B is a method in which the UE changes and transmits allocated resources of the frequency domain by configured frequency offset for each slot. In inter-slot frequency hopping, a starting RB during a nsμ slot may be represented through Equation 5.
In Equation 5, nsμ denotes a current slot number in multi-slot PUSCH transmission, RBstart denotes a starting RB in UL BWP and is calculated from a frequency resource allocation method. RBoffset represents a frequency offset between two hops through a higher layer parameter.
Hereinafter, an inter-repetition frequency hopping method supporting in a PUSCH repetition transmission type B is to move and transmit resources allocated in a frequency domain for one or a plurality of actual repetitions within each nominal repetition by configured frequency offset. RBstart(n), which is an index of a starting RB in a frequency domain for one or a plurality of actual repetitions within the n-th nominal repetition, may follow Equation 6.
In Equation 6, n is an index of nominal repetition, and RBoffset denotes a RB offset between two hops through a higher layer parameter.
In the following description, a method of measuring and reporting a channel state in a 5G communication system to which the disclosure may be applied will be described in detail. Channel state information (CSI) may include channel quality information (CQI), precoding matrix index (PMI), CSI-RS resource indicator (CRI), SS/PBCH block resource indicator (SSBRI), layer indicator (LI), rank indicator (RI), and/or L1-reference signal received power (RSRP), and the like. The base station may control time and frequency resources for the above-described CSI measurement and reporting of the UE.
For the above-described CSI measurement and reporting, the UE may receive a configuration of setting information (CSI-ReportConfig) for the N (≥1) number of CSI reporting, setting information (CSI-ResourceConfig) for the M (≥1) number of RS transmission resources, and one or two trigger states (CSI-AperiodicTriggerStateList, CSI-SemiPersistentOnPUSCH-TriggerStateList) list information through higher layer signaling. Configuration information for the above-described CSI measurement and reporting may be described in more detail in Table 33a to Table 39 as follows.
For the above-described CSI report configuration (CSI-ReportConfig), each report configuration (CSI-ReportConfig) may be associated with a CSI resource configuration associated with the corresponding report configuration and an downlink (DL) bandwidth part identified by a higher layer parameter bandwidth part identifier (bwp-id) given as CSI-ResourceConfig. As a time domain reporting operation for each report configuration CSI-ReportConfig, ‘Aperiodic’, ‘Semi-Persistent’, and ‘Periodic’ methods are supported, which may be configured from the base station to the UE by a reportConfigType parameter configured from the higher layer. The semi-persistent CSI reporting method supports ‘PUCCH-based semi-persistent (semi-PersistentOnPUCCH)’ and ‘PUSCH-based semi-persistent (semi-PersistentOnPUSCH)’. In the case of the periodic or semi-permanent CSI reporting method, the UE may receive a configuration of a PUCCH or PUSCH resource to transmit CSI from the base station through higher layer signaling. The period and slot offset of a PUCCH or PUSCH resource to transmit CSI may be given as numerology of an uplink (UL) bandwidth part configured to transmit CSI reporting. In the case of the aperiodic CSI reporting method, the UE may receive scheduling of PUSCH resources to transmit CSI from the base station through L1 signaling (the above-described DCI format 0_1).
For the above-described CSI resource configuration (CSI-ResourceConfig), each CSI resource configuration CSI-ReportConfig may include the S (≥1) number of CSI resource sets (given by higher layer parameter csi-RS-ResourceSetList). The CSI resource set list may be composed of a non-zero power (NZP) CSI-RS resource set and an SS/PBCH block set or may be composed of a CSI-interference measurement (CSI-IM) resource set. Each CSI resource configuration may be located in a downlink (DL) bandwidth part identified by a higher layer parameter bwp-id, and the CSI resource configuration may be connected to a CSI reporting configuration of the same downlink bandwidth part. A time domain operation of the CSI-RS resource in the CSI resource configuration may be configured to one of ‘aperiodic’, ‘periodic’ or ‘semi-permanent’ from a higher layer parameter resourceType. For periodic or semi-permanent CSI resource configuration, the number of CSI-RS resource sets may be limited to S=1, and the configured period and slot offset may be given as numerology of a downlink bandwidth part identified by a bwp-id. The UE may receive one or more CSI resource configurations for channel or interference measurement from the base station through higher layer signaling, and include, for example, the following CSI resources.
For CSI-RS resource sets associated with resource configuration in which the higher layer parameter resourceType is configured to ‘aperiodic’, ‘periodic’, or ‘semi-permanent’, a trigger state for CSI report configurations in which a reportType is configured to ‘aperiodic’ and a resource configuration for channel or interference measurement for one or a plurality of component cells (CCs) may be configured to a higher layer parameter CSI-AperiodicTriggerStateList.
Aperiodic CSI reporting of the UE may use a PUSCH, periodic CSI reporting may use a PUCCH, and semi-permanent CSI reporting may be performed using a PUCCH after being activated with the PUSCH and a MAC control element (MAC CE) in the case of being triggered or activated by DCI. As described above, a CSI resource configuration may also be configured to aperiodic, periodic, or semi-permanent. A combination between a CSI report configuration and a CSI resource configuration may be supported based on Table 40.
Aperiodic CSI reporting may be triggered by a “CSI request” field of the above-described DCI format 0_1 corresponding to scheduling DCI for the PUSCH. The UE may monitor the PDCCH, acquire a DCI format 0_1, and acquire scheduling information and a CSI request indicator for the PUSCH. The CSI request indicator may be configured to NTS (=0, 1, 2, 3, 4, 5, or 6) bits and be determined by higher layer signaling (reportTriggerSize). One trigger state among one or a plurality of aperiodic CSI reporting trigger states that may be configured by higher layer signaling (CSI-AperiodicTriggerStateList) may be triggered by a CSI request indicator.
In the case that all bits of the CSI request field are 0, this may mean that CSI reporting is not requested.
When the number (M) of CSI trigger states in the configured CSI-AperiodicTriggerStateLite is greater than 2NTs−1, the M number of CSI trigger states may be mapped to 2NTs−1 according to a predefined mapping relationship, and one trigger state of 2NTs−1 trigger states may be indicated by the CSI request field.
When the number (M) of CSI trigger states in the configured CSI-AperiodicTriggerStateLite is smaller than or equal to 2NTs−1, one of the M number of CSI trigger states may be indicated by the CSI request field.
Table 41 illustrates an example of a relationship between a CSI request indicator and a CSI trigger state that may be indicated by the corresponding indicator.
The UE may perform measurement on the CSI resource in the CSI trigger state triggered by the CSI request field, and generate CSI (including at least one of the above-described CQI, PMI, CRI, SSBRI, LI, RI, or L1-RSRP) therefrom. The UE may transmit the acquired CSI using the PUSCH scheduled by the corresponding DCI format 0_1. In the case that 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in the DCI format 01 indicates “1”, uplink data (UL-SCH) and acquired CSI may be multiplexed and transmitted to PUSCH resources scheduled by the DCI format 0_1. In the case that 1 bit corresponding to an uplink data indicator (UL-SCH indicator) in the DCI format 0_1 indicates “0”, only CSI without uplink data (UL-SCH) may be mapped and transmitted to PUSCH resources scheduled by the DCI format 0_1
According to an example 1400 of
An example 1400 of
In an example 1410 of
The aperiodic CSI reporting may include at least one or both of a CSI part 1 and a CSI part 2, and in the case that the aperiodic CSI reporting is transmitted through the PUSCH, it may be multiplexed with the transport block. After the CRC is inserted into input bits of the aperiodic CSI for multiplexing, the CRC may be encoded and rate matched, and then mapped to a resource element in the PUSCH in a specific pattern and transmitted. The CRC insertion may be omitted according to a coding method or a length of input bits. The number of modulation symbols calculated for rate matching when multiplexing CSI Part 1 or CSI part 2 included in the aperiodic CSI reporting may be calculated, as illustrated in Table 43.
In particular, in the case of PUSCH repetition transmission methods A and B, the UE may multiplex and transmit aperiodic CSI reporting only to the first repetition transmission during PUSCH repetition transmission. This is because the multiplexed aperiodic CSI reporting information is encoded in a polar code method, and in this case, in order to be multiplexed in several PUSCH repetitions, each PUSCH repetition should have the same frequency and time resource allocation, and in particular, in the case of the PUSCH repetition type B, because each actual repetition may have different OFDM symbol lengths, the aperiodic CSI reporting may be multiplexed and transmitted only in the first PUSCH repetition.
Further, for the PUSCH repetition transmission type B, in the case that the UE schedules aperiodic CSI reporting without scheduling for transport blocks or receives DCI for activating semi-permanent CSI reporting, even if the number of PUSCH repetition transmissions configured by higher layer signaling is greater than 1, a value of nominal repetition may be assumed to 1. Further, in the case that the UE schedules or activates aperiodic or semi-permanent CSI reporting without scheduling for transport blocks based on the PUSCH repetition transmission type B, the UE may expect first nominal repetition to be the same as first actual repetition. After semi-permanent CSI reporting is activated with DCI, for a PUSCH transmitted including semi-permanent CSI based on the PUSCH repetition transmission type B without scheduling for DCI, when the first nominal repetition is different from the first actual repetition, transmission for the first nominal repetition may be ignored.
In LTE and NR, the UE may perform a procedure for reporting a capability supported by the UE to the serving base station in a state connected to the serving base station. In the following description, this is referred to as UE capability reporting.
The base station may transmit a UE capability inquiry message requesting a capability report to the UE in a connected state. The message may include a UE capability request for each radio access technology (RAT) type of the base station. The request for each RAT type may include supporting frequency band combination information. Further, in the case of the UE capability inquiry message, each UE capability for a plurality of RAT types may be requested through one RRC message container transmitted by the base station, or the base station may include a UE capability inquiry message including a UE capability request for each RAT type multiple times and transmit the message to the UE. That is, the UE capability inquiry is repeated multiple times within one message, and the UE may constitute and report to the corresponding UE capability information message multiple times. A next generation mobile communication system may request a UE capability for multi-RAT dual connectivity (MR-DC) including NR, LTE, and EN-DC (E-UTRA-NR dual connectivity). Further, although the UE capability inquiry message is generally initially transmitted after the UE is connected to the base station, the base station may request the UE capability inquiry message under any condition when necessary.
In the above step, the UE that has received a UE capability report request from the base station constitutes a UE capability according to the RAT type and band information requested from the base station. Hereinafter, a method for the UE to constitute UE capabilities in the NR system is summarized.
1. When the UE receives a list of LTE and/or NR bands from the base station by a UE capability request, the UE constitutes a band combination (BC) for EN-DC and NR stand alone (SA). That is, the UE constitutes a BC candidate list for EN-DC and NR SA based on bands requested to the base station through a FreqBandList. Further, bands have priorities in the order described in the FreqBandList.
2. In the case that the base station configures a “eutra-nr-only” flag or a “eutra” flag to request UE capability reporting, the UE completely removes those for NR SA BCs from the constituted BC candidate list. This operation may occur only in the case that the LTE base station (eNB) requests a “eutra” capability.
3. Thereafter, the UE removes fallback BCs from the candidate list of BCs constituted in the above step. Here, the fallback BC means a BC that may be obtained by removing a band corresponding to at least one SCell from any BC, and because a BC before removing a band corresponding to at least one SCell may already cover the fallback BC, the fallback BC may be omitted. This step is applied even to MR-DC, that is, to LTE bands. The remaining BCs after this step are a final “candidate BC list”.
4. The UE selects BCs appropriate for a requested RAT type from the final “candidate BC list” to select BCs to report. In this step, the UE constitutes a supportedBandCombinationList in the predetermined order. That is, the UE constitutes the BC and UE capabilities to report according to the order of the preconfigured rat-Type (nr->eutra-nr->eutra). Further, the UE constitutes a featureSetCombination for the constituted supportedBandCombinationList, and constitutes a list of “candidate feature set combination” in the candidate BC list from which a list for a fallback BC (including capabilities of the same or lower level) is removed. The above “candidate feature set combination” includes both feature set combinations for NR and EUTRA-NR BC, and may be obtained from the feature set combination of the UE-NR-Capabilities and UE-MRDC-Capabilities containers.
5. Further, when the requested rat Type is eutra-nr and has an effect, featureSetCombinations is included in both containers of UE-MRDC-Capabilities and UE-NR-Capabilities. However, a feature set of NR includes only UE-NR-Capabilities.
After UE capabilities are constituted, the UE transmits a UE capability information message including the UE capabilities to the base station. Thereafter, the base station performs appropriate scheduling and transmission and reception management for the UE based on the UE capabilities received from the UE.
With reference to
Main functions of the NR SDAPs 1525 and 1570 may include some of the following functions.
For the SDAP layer device, the UE may receive a configuration on whether to use a header of the SDAP layer device or whether to use a function of the SDAP layer device for each PDCP layer device, each bearer, or each logical channel with a radio resource control (RRC) message. In the case that the SDAP header is configured, the UE may instruct to update or reconfigure mapping information on uplink and downlink QoS flows and data bearers with non-access stratum (NAS) reflective quality of service (QoS) and access stratum (AS) reflective QoS of the SDAP header. The SDAP header may include QoS flow ID information indicating a QoS. The QoS information may be used as a data processing priority and scheduling information for supporting a smooth service.
Main functions of the NR PDCPs 1530 and 1565 may include some of the following functions.
In the above description, reordering of the NR PDCP device may refer to a function of reordering PDCP PDUs received from a lower layer based on a PDCP sequence number (SN) and include a function of transferring data to a higher layer in the rearranged order. Alternatively, the reordering of the NR PDCP device may include a function of directly transferring data without considering the order, a function of rearranging the order and recording lost PDCP PDUs, a function of reporting a status of lost PDCP PDUs to the transmitting side, and a function of requesting retransmission of lost PDCP PDUs.
Main functions of the NR RLCs 1535 and 1560 may include some of the following functions.
In the above description, in-sequence delivery of the NR RLC device may mean a function of sequentially transferring RLC SDUs received from a lower layer to a higher layer. In-sequence delivery of the NR RLC device may include a function of reassembling and transferring an original RLC SDU in the case that an original RLC SDU is divided into several RLC SDUs and received, a function of rearranging received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN), a function of rearranging the order and recording lost RLC PDUs, a function of reporting a status of lost RLC PDUs to the transmitting side, and a function of requesting retransmission of lost RLC PDUs. In-sequence delivery of the NR RLC device may include a function of sequentially transferring, in the case that there is a lost RLC SDU, only RLC SDUs before the lost RLC SDU to a higher layer or a function of sequentially transferring all RLC SDUs received before the timer starts to the higher layer, when a predetermined timer has expired even if there is a lost RLC SDU. Alternatively, in-sequence delivery of the NR RLC device may include a function of sequentially transferring all RLC SDUs received so far to the higher layer, when a predetermined timer has expired even if there is a lost RLC SDU. Further, the RLC PDUs may be processed in the order of reception (regardless of the order of serial numbers and sequence numbers, in the order of arrival) and transferred to the PDCP device regardless of order (out-of sequence delivery), and in the case of a segment, the NR RLC device may receive segments stored in a buffer or to be received later, reconstitute segments into one complete RLC PDU, and then transfer the one complete RLC PDU to the NR PDCP device. The NR RLC layer may not include a concatenation function, and the NR MAC layer may perform a concatenation function in the NR RLC layer or a function of the NR RLC layer may be replaced with a multiplexing function of the NR MAC layer.
In the above description, out-of-sequence delivery of the NR RLC device may mean a function of directly transferring RLC SDUs received from a lower layer to a higher layer regardless of order and may include a function of reassembling and transferring several RLC SDUs in the case that one RLC SDU is originally divided into several RLC SDUs and received and a function of storing RLC SNs or PDCP sequence numbers (SNs) of received RLC PDUs, arranging the order, and recording lost RLC PDUs.
The NR MACs 1540 and 1555 may be connected to several NR RLC layer devices constituted in one UE, and main functions of the NR MAC may include some of the following functions.
NR PHY layers 1545 and 1550 may perform operations of channel-coding and modulating higher layer data, making the higher layer data into OFDM symbols and transmitting the OFDM symbols through a radio channel, or demodulating OFDM symbols received through a radio channel, channel-decoding the OFDM symbols, and transferring the OFDM symbols to a higher layer.
The detailed structure of the radio protocol structure may be variously changed according to a carrier (or cell) operation method. For example, in the case that the base station transmits data to the UE based on a single carrier (or cell), the base station and the UE use a protocol structure having a single structure for each layer, as in 1500. In the case that the base station transmits data to the UE based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and the UE have a single structure up to RLC, as in 1510, but use a protocol structure for multiplexing the PHY layer through the MAC layer. As another example, in the case that the base station transmits data to the UE based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and the UE have a single structure up to RLC, as in 1520, but use a protocol structure for multiplexing the PHY layer through the MAC layer.
With reference to the descriptions related to the above-described PDCCH and beam configuration, it is difficult to achieve required reliability in scenarios requiring high reliability such as URLLC because PDCCH repetition transmission is not currently supported in Rel-15 and Rel-16 NRs. In the disclosure, a PDCCH repetition transmission method through multiple transmission points (TRPs) is provided to improve PDCCH reception reliability of the UE. Specific methods thereof are specifically described in the following examples.
Hereinafter, embodiments of the disclosure will be described in detail with accompanying drawings. The contents of this disclosure are applicable to FDD and TDD systems. Hereinafter, higher-layer signaling (or higher layer signaling) in the disclosure is a method of transmitting a signal from a base station to a UE using a downlink data channel of a physical layer, or from a UE to a base station using an uplink data channel of the physical layer and may also be referred to as RRC signaling, PDCP signaling, or a medium access control (MAC) control element (MAC CE).
Hereinafter, in the disclosure, in determining whether cooperative communication is applied, it is possible for the UE to use various methods in which a PDCCH(s) allocating a PDSCH to which cooperative communication is applied has(have) a specific format, or in which a PDCCH(s) allocating a PDSCH to which cooperative communication is applied include(s) a specific indicator indicating whether communication is applied, or in which a PDCCH(s) allocating a PDSCH to which cooperative communication is applied is(are) scrambled with specific RNTI, or in which cooperative communication application is assumed in a specific segment indicated by a higher layer, and the like. Hereinafter, for convenience of description, the case that the UE receives the PDSCH to which cooperative communication is applied based on conditions similar to the above description will be referred to as an NC-JT case.
Hereinafter, in the disclosure, determining a priority between A and B may be variously referred to as selecting one having a higher priority according to a predetermined priority rule and performing a corresponding operation or omitting or dropping an operation for one having a lower priority.
Hereinafter, in the disclosure, the examples are described through a plurality of embodiments, but they are not independent, and one or more embodiments may be applied simultaneously or in combination.
According to an embodiment of the disclosure, non-coherent joint transmission (NC-JT) may be used for a UE to receive a PDSCH from a plurality of TRPs.
The 5G wireless communication system may support not only services requiring high transmission rates, but also services with very short transmission delays and services requiring high connection density, unlike conventional ones. In a wireless communication network including multiple cells, transmission and reception points (TRPs), or beams, coordinated transmission between each cell, TRP or/and beam may increase the strength of a signal received by a UE or efficiently perform interference control between each cell, TRP or/and beam to satisfy various service requirements.
Joint transmission (JT) is a typical transmission technology for the above-described cooperative communication, and transmits a signal to one UE through a plurality of different cells, TRPs, or/and beams, thereby increasing the strength or throughput of the signal received by the UE. In this case, characteristics of a channel between each cell, TRP or/and beam and the UE may be significantly different, and in particular, in the case of non-coherent joint transmission (NC-JT) supporting non-coherent precoding between each cell, TRP or/and beam, individual precoding, MCS, resource allocation, TCI indication, and the like may be required according to channel characteristics of each link between each cell, TRP or/and beam and UE.
The above-described NC-JT transmission may be applied to at least one of a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), a physical uplink shared channel (PUSCH), or a physical uplink control channel (PUCCH). During PDSCH transmission, transmission information such as precoding, MCS, resource allocation, and TCI is indicated as DL DCI, and for NC-JT transmission, the transmission information should be independently indicated for each cell, TRP or/and beam. This becomes a major factor in increasing a payload required for DL DCI transmission, which may adversely affect reception performance of a PDCCH transmitting DCI. Therefore, it is necessary to carefully design the tradeoff between a DCI information amount and a control information reception performance for JT support of a PDSCH.
With reference to
With reference to
In the case of C-JT, a TRP A 1605 and a TRP B 1610 transmit single data (PDSCH) to an UE 1615, and joint precoding may be performed in a plurality of TRPs. This may mean that a DMRS is transmitted through the same DMRS ports in order for the TRP A 1605 and the TRP B 1610 to transmit the same PDSCH. For example, each of the TRP A 1605 and the TRP B 1610 may transmit a DRMS to the UE through a DMRS port A and a DMRS B. In this case, the UE may receive one DCI information for receiving one PDSCH demodulated based on the DMRS transmitted through the DMRS port A and the DMRS B.
In the case of NC-JT, a PDSCH is transmitted to a UE 1635 for each cell, TRP or/and beam, and individual precoding may be applied to each PDSCH. Each cell, TRP or/and beam may transmit different PDSCHs or different PDSCH layers to the UE to improve throughput compared to single cell, TRP or/and beam transmission. Further, each cell, TRP or/and beam repeatedly transmits the same PDSCH to the UE, thereby improving reliability compared to single cell, TRP or/and beam transmission. For convenience of description, hereinafter, a cell, a TRP, or/and a beam are collectively referred to as a TRP.
In this case, various radio resource allocations may be considered in the case that all frequency and time resources used in a plurality of TRPs for PDSCH transmission are the same (1640), in the case that frequency and time resources used in a plurality of TRPs do not overlap at all (1645), and in the case that some of frequency and time resources used in a plurality of TRPs overlap (1650).
To support NC-JT, DCI of various forms, structures, and relationships may be considered in order to simultaneously allocate a plurality of PDSCHs to one UE.
With reference to
A case #2, 1715 illustrates an example in which each control information (DCI) on PDSCHs of the (N−1) number of additional TRPs is transmitted and each of these DCI is dependent on control information on the PDSCHs transmitted from the serving TRP in a situation in which the different (N−1) number of PDSCHs are transmitted from the (N−1) number of additional TRPs (TRP #1 to TRP #(N−1)) in addition to the serving TRP (TRP #0) used during single PDSCH transmission.
For example, in the case of DCI #0, which is control information on the PDSCH transmitted from the serving TRP (TRP #0), it includes all information elements of a DCI format 1_0, DCI format 1_1, and DCI format 1_2, but in the case of shortened DCI (hereinafter, sDCI) (sDCI #0 to sDCI #(N−2)), which is control information on PDSCHs transmitted from cooperative TRPs (TRP #1 to TRP #(N−1)), it may include only some of information elements of a DCI format 1_0, DCI format 1_1, and DCI format 1_2. Therefore, in the case of sDCI that transmits control information on PDSCHs transmitted from cooperative TRPs, because a payload is small compared to normal DCI (nDCI) that transmits PDSCH related control information transmitted from serving TRPs, the sDCI may include reserved bits compared to nDCI.
In the above-described case #2, each PDSCH control or allocation degree of freedom may be limited according to the content of information elements included in sDCI, but because a reception performance of sDCI is superior to that of nDCI, a probability of occurrence of a difference in coverage for each DCI may be reduced.
A case #3, 1720 illustrates an example in which one control information on PDSCHs of the (N−1) number of additional TRPs is transmitted and the DCI is dependent on control information on PDSCHs transmitted from the serving TRP in a situation in which the different (N−1) number of PDSCHs are transmitted from the (N−1) number of additional TRPs (TRP #1 to TRP #(N−1)) in addition to the serving TRP (TRP #0) used during single PDSCH transmission.
For example, in the case of DCI #0, which is control information on the PDSCH transmitted from the serving TRP (TRP #0), it includes all information elements of a DCI format 1_0, DCI format 1_1, and DCI format 1_2, and in the case of control information on PDSCHs transmitted from the cooperative TRP (TRP #1 to TRP #(N−1)), only some of information elements of a DCI format 1_0, DCI format 1_1, and DCI format 1_2 may be collected in one ‘secondary’ DCI (sDCI) and transmitted. For example, the sDCI may include at least one of HARQ related information such as frequency domain resource assignment, time domain resource assignment, and MCS of cooperative TRPs. Further, information not included in sDCI, such as a bandwidth part (BWP) indicator or carrier indicator, may follow DCI (DCI #0, normal DCI, nDCI) of the serving TRP.
In the case #3, 1720, each PDSCH control or allocation degree of freedom may be limited according to the content of information elements included in sDCI, but a reception performance of sDCI may be adjusted, and compared to the case #1, 1710 or the case #2, 1715, complexity of DCI blind decoding of the UE may be reduced.
A case #4, 1725 is an example in which control information on PDSCHs transmitted from the (N−1) number of additional TRPs is transmitted in the same DCI (Long DCI) as that of control information on PDSCHs transmitted from serving TRPs in a situation in which the different (N−1) number of PDSCHs are transmitted from the (N−1) number of additional TRPs (TRP #1 to TRP #(N−1)) in addition to the serving TRP (TRP #0) used during single PDSCH transmission. That is, the UE may acquire control information on PDSCHs transmitted from different TRPs (TRP #0 to TRP #(N−1)) through single DCI. In the case #4 (N115), the complexity of DCI blind decoding of the UE may not increase, but the degree of freedom in PDSCH control or allocation may be low, such as the number of cooperative TRPs being limited according to the long DCI payload limit.
In the following descriptions and embodiments, sDCI may refer to various auxiliary DCI, such as shortened DCI, secondary DCI, or normal DCI (DCI format 1_0 to 1_1 described above) including PDSCH control information transmitted from cooperative TRP, and in the case that special restrictions are not specified, the description is similarly applicable to the various auxiliary DCI.
In the following descriptions and embodiments, the above-described case #1, 1710, case #2, 1715, and case #3, 1720 in which one or more DCI (PDCCH) is used for supporting NC-JT may be classified into multiple PDCCH-based NC-JT, and the above-described case #4, 1725 in which single DCI (PDCCH) is used for supporting NC-JT may be classified into single PDCCH-based NC-JT. In multiple PDCCH-based PDSCH transmission, a CORESET in which DCI of a serving TRP (TRP #0) is scheduled and a CORESET in which DCI of cooperative TRPs (TRP #1 to TRP #(N−1)) is scheduled may be distinguished. As a method of distinguishing CORESETs, there may be a method of distinguishing through a higher layer indicator for each CORESET, a method of distinguishing through a beam configuration for each CORESET, and the like. Further, in the single PDCCH-based NC-JT, single DCI schedules a single PDSCH having a plurality of layers instead of scheduling a plurality of PDSCHs, and the above-described plurality of layers may be transmitted from a plurality of TRPs. In this case, the connection relationship between the layer and the TRP transmitting the layer may be indicated through a transmission configuration indicator (TCI) indication for the layer.
In the embodiments of the disclosure, a “cooperative TRP” may be replaced with various terms such as “cooperative panel” or “cooperative beam” in actual application.
In embodiments of the disclosure, “the case that NC-JT is applied” may be variously interpreted according to the situation such as “the case that the UE simultaneously receives one or more PDSCHs in one BWP”, “the case that the UE simultaneously receives the PDSCH based on two or more transmission configuration indicator (TCI) indications in one BWP”, and “the case that the PDSCH received by the UE is associated with one or more DMRS port groups”, but for convenience, one expression was used.
In the disclosure, a radio protocol structure for NC-JT may be variously used according to TRP deployment scenarios. For example, in the case that there is no or small backhaul delay between cooperative TRPs, a method (CA-like method) using a structure based on MAC layer multiplexing similar to 1510 of
A UE supporting C-JT/NC-JT may receive parameters or setting values related to C-JT/NC-JT from higher layer configurations, and set RRC parameters of the UE based on this. For a higher layer configuration, the UE may utilize a UE capability parameter, for example, tci-StatePDSCH. Here, the UE capability parameter, for example, tci-StatePDSCH may define TCI states for the purpose of PDSCH transmission, and the number of TCI states may be configured to 4, 8, 16, 32, 64, and 128 in FR1 and be configured to 64 and 128 in FR2, and maximum 8 states that may be indicated by the TCI field 3 bits of the DCI through the MAC CE message among the configured number may be configured. The maximum value 128 means a value indicated by maxNumberConfiguredTCIstatesPerCC in the tci-StatePDSCH parameter included in capability signaling of the UE. In this way, a series of configuration processes from a higher layer configuration to an MAC CE configuration may be applied to a beamforming instruction or a beamforming change command for at least one PDSCH in one TRP.
According to an embodiment of the disclosure, a downlink control channel for NC-JT transmission may be configured based on Multi-PDCCH.
In NC-JT based on multiple PDCCHs, when transmitting DCI scheduling the PDSCH of each TRP, it is possible to have a CORESET or search space distinguished for each TRP. The CORESET or search space for each TRP may be configured as in at least one of the following cases.
As described above, by dividing the CORESET or search space by TRP, it is possible to classify PDSCH and HARQ-ACK information for each TRP, and thus, independent HARQ-ACK codebook generation and independent PUCCH resource use for each TRP are possible.
The above configuration may be independent for each cell or each BWP. For example, two different CORESETPoolIndex values are configured to a PCell, but no CORESETPoolIndex value may be configured in a specific SCell. In this case, NC-JT transmission is constituted in the PCell, whereas it may be regarded that NC-JT transmission is not constituted in the SCell in which the CORESETPoolIndex value is not configured.
According to another embodiment of the disclosure, a downlink beam for NC-JT transmission may be configured based on a single-PDCCH.
In single PDCCH-based NC-JT, a PDSCH in which a plurality of TRPs are transmitted with one DCI may be scheduled. In this case, the number of TCI states may be used with a method of indicating the number of TRPs transmitting the corresponding PDSCH. That is, when the number of TCI states indicated in DCI scheduling the PDSCH is two, it may be regarded as single PDCCH-based NC-JT transmission, and when the number of TCI states is one, it may be regarded as single-TRP transmission. The TCI states indicated by the above DCI may correspond to one or two TCI states among TCI states activated by an MAC-CE. In the case that TCI states of DCI correspond to two TCI states activated by an MAC-CE, the correspondence between a TCI codepoint indicated by DCI and TCI states activated by an MAC-CE is established, and TCI states activated by the MAC-CE and corresponding to the TCI codepoint may be two.
The above configuration may be independent for each cell or each BWP. For example, in a Pcell, activated TCI states corresponding to one TCI codepoint may be maximum two, whereas in a specific Scell, activated TCI states corresponding to one TCI codepoint may be maximum one. In this case, NC-JT transmission is constituted in the PCell, but it may be regarded that NC-JT transmission is not constituted in the above-described SCell.
With reference to
Downlink path attenuation=transmission power of base station signal—RSRP measured by UE [Equation 7]
In Equation 7, transmission power of the base station signal means transmission power of the downlink path attenuation estimation signal transmitted by the base station. The downlink path attenuation estimation signal transmitted by the base station may be a cell-specific reference signal (CRS) or synchronization signal block (SSB). In the case that the path attenuation estimation signal is a cell-specific reference signal (CRS), the transmission power of the base station signal means transmission power of the CRS, and may be transmitted to the UE through a referenceSignalPower parameter of system information. In the case that a path attenuation estimation signal is a synchronization signal block (SSB), transmission power of the base station signal means transmission power of a demodulation reference signal (DMRS) transmitted to a secondary synchronization signal (SSS) and a PBCH, and may be transmitted to the UE through an ss-PBCH-BlockPower parameter of system information. In step 1820, the UE may receive RRC parameters for uplink transmission power control from the base station through UE-specific RRC or common RRC. In this case, the received transmission power control parameters may be different from each other according to the type of an uplink channel and the type of a signal transmitted to uplink. That is, transmission power control parameters applied to transmission of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), and a sounding reference signal (SRS) may differ from each other. Further, as described above, transmission power control parameters received by the UE through the SIB from the base station before the RRC connection configuration or transmission power control parameters used by the UE with pre-promised values before the RRC connection configuration may be included in the RRC parameter transmitted from the base station after the RRC connection configuration. Further, power headroom reporting (PHR) configuration information may be included in the RRC parameter, and in this case, the PHR configuration information may include a timer (e.g., phr-PeriodicTimer or phr-ProhibitTimer) value associated with PHR. The UE may use the RRC parameter value received from the base station after the RRC connection configuration for uplink transmission power control. In step 1825, the UE may receive a path attenuation estimation signal from the base station. More specifically, the base station may configure a channel state information-reference signal (CSI-RS) with a path attenuation estimation signal of the UE after an RRC connection configuration of the UE. In this case, the base station may transmit information on transmission power of the CSI-RS to the UE through the powerControlOffsetSS parameter of UE dedicated RRC information. In this case, powerControlOffsetSS may mean a transmission power difference (offset) between the SSB and the CSI-RS. In step 1830, the UE may estimate a downlink path attenuation value and configure an uplink transmission power value. More specifically, the UE may measure downlink RSRP using the CSI-RS and estimate the downlink path attenuation value through Equation 7 using information on transmission power of the CSI-RS received from the base station. The UE may configure uplink transmission power values for PUCCH, PUSCH, and SRS transmission based on the estimated path attenuation value. In step 1835, the UE may perform PHR to the base station. In the case that a timer associated with the PHR received in step 1820 has expired or the change in the path attenuation value is a specific threshold value or more, the UE according to an embodiment of the disclosure may trigger the PHR and perform step 1835. In the disclosure, PH may mean the difference between maximum output power (Pcmax) of the UE and current transmission power (Ppusch) of the UE. In step 1840, the base station may optimize a system operation based on the reported power headroom. For example, in the case that a power headroom value reported by a specific UE to the base station is the positive number, the base station may allocate more resources (RBs) to the corresponding UE to increase system yield. In step 1845, the UE may receive a transmission power control command (TPC) from the base station. For example, when a power headroom value reported by a specific UE to the base station is a negative number, the base station may allocate fewer resources to the corresponding UE or reduce transmission power of the corresponding UE through a transmission power control command. Thereby, system yield may be increased or unnecessary power consumption of the UE may be reduced. In step 1850, the UE may update transmission power based on the TPC command. In this case, the TPC command may be transmitted to the UE through UE-specific DCI or group common DCI. Therefore, the base station may dynamically control transmission power of the UE through the TPC command. In step 1855, the UE may perform uplink transmission based on the updated transmission power.
Steps 1810 to 1855 of
PUSCH transmission power may be determined through Equation 8.
In Equation 8, PCMAX,f,c(i) is maximum transmission power configured to the UE for a carrier f of a serving cell c at a PUSCH transmission time point i. P0
The TPC command is divided into an accumulated mode and an absolute mode, and one of two modes is determined by a higher-layer signal. The accumulation mode may be increased or decreased according to the TPC command in a form in which a currently determined power control adaptation value is accumulated to a value indicated by the TPC command, and has a relationship of fb,f,c(i,l)=fb,f,c(i−i0,l)+ΣδPUSCH,b,f,c. δPUSCH,b,f,c is a value indicated in the TPC command. In the absolute mode, the value is determined by the TPC command regardless of the currently determined power control adaptation value, and has a relationship of fb,f,c(i,l)=δPUSCH,b,f,c. Table 44 illustrates values that may be indicated in the TPC command.
The following Equation 9 is an equation for determining PUCCH transmission power.
In Equation 9, P0
According to the description of the above-described PUSCH and aperiodic/semi-permanent CSI reporting, in the current Rel-15/16 NR, the aperiodic CSI reporting may be multiplexed only in a first PUSCH or the first actual repetition according to a PUSCH repetition transmission type A or B. That is, the aperiodic CSI reporting may be transmitted with only a single TRP using a single transmission beam. In Rel-17 FeMIMO, in order to acquire better reliability during PUSCH repetition transmission, a method of extending and supporting to a plurality of TRP-based PUSCH repetitions capable of securing spatial diversity by applying a plurality of transmission beams to PUSCH repetition is being discussed. In this discussion, discussions are mainly being made to support PUSCH repetition transmissions to a plurality of TRPs by applying different beams to each PUSCH repetition based on the existing PUSCH repetition transmission type A or B. In this case, in the case of a plurality of TRP-based PUSCH repetition transmission methods A or B, and in the case that aperiodic CSI reporting is multiplexed and transmitted, when it is multiplexed only in first PUSCH repetition as in the existing Rel-15/16 scheme, transmission to the corresponding TRP may fail due to a channel deterioration factor such as blockage; thus, a method of multiplexing once for each transmission to each TRP may be required. In this case, as described above, upon repeatedly transmitting each PUSCH due to characteristics of a polar code, when time and frequency resource allocation values, that is, the number of resource elements (REs) allocated to the IE is the same, the base station may perform combining after reception. Therefore, in the case that the aperiodic CSI reporting is multiplexed while the transport block is transmitted using the PUSCH repetition transmission type A or B, a method of determining which PUSCH repetition to multiplex the aperiodic CSI reporting among all PUSCH repetitions may be needed. Further, in the case that aperiodic or semi-permanent CSI reporting is multiplexed when no transport block is transmitted in the PUSCH repetition transmission type B, even if the number of PUSCH repetitions is configured to greater than 1, it should be able to be ensured that at least one transmission is possible for each TRP. In this disclosure, in the case of multiplexing or transmitting aperiodic/semi-permanent CSI reporting, a method of multiplexing or transmitting PUSCH repetition transmissions considering a plurality of TRPs is provided, thereby improving CSI reception reliability at the base station. Specific methods thereof are specifically described in the following examples.
In the following description of the disclosure, for convenience, a cell, transmission point, panel, beam, or/and transmission direction that may be distinguished through higher layer/L1 parameters such as a TCI state or spatial relation information, or cell ID, TRP ID, panel ID, reference signal (RS) resource index (e.g., values indicated by the SRI field in DCI of Embodiment 1 to be described later) are unified and described as a transmission reception point (TRP). Therefore, in actual application, the TRP may be appropriately replaced with one of the above terms.
Hereinafter, in the disclosure, in determining whether cooperative communication is applied, the UE may use various methods in which a PDCCH(s) allocating a PDSCH to which cooperative communication is applied has a specific format, or a PDCCH(s) allocating a PDSCH to which cooperative communication is applied may include a specific indicator indicating whether cooperative communication is applied and in which a PDCCH(s) allocating a PDSCH to which cooperative communication is applied may be scrambled with specific RNTI, or in which cooperative communication is assumed in a specific section indicated by a higher layer. Hereinafter, for convenience of description, the case that the UE receives the PDSCH to which cooperative communication is applied based on conditions similar to the above will be referred to as an NC-JT case.
Hereinafter, embodiments of the disclosure will be described in detail with accompanying drawings. Hereinafter, the base station is a subject performing resource allocation of a UE, and may be at least one of a gNode B, a gNB, an eNode B, a node B, a base station (BS), a radio access unit, a base station controller, or a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. Hereinafter, an embodiment of the disclosure is described using a 5G system as an example, but the embodiment of the disclosure may be applied to other communication systems having a similar technical background or channel type. For example, LTE or LTE-A mobile communication and mobile communication technology developed after 5G may be included therein. Accordingly, the embodiments of the disclosure may be applied to other communication systems through some modification without significantly departing from the scope of the disclosure as determined by a person skilled in the art. The contents of this disclosure are applicable to FDD and TDD systems.
Further, in describing the disclosure, in the case that it is determined that a detailed description of a related function or constitution may unnecessarily obscure the gist of the disclosure, a detailed description thereof will be omitted. Terms described below are terms defined in consideration of functions in the disclosure, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.
Hereinafter, in describing the disclosure, higher layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling.
Further, L1 signaling may be signaling corresponding to at least one or a combination of one or more of signaling methods using the following physical layer channels or signaling.
Hereinafter, in the disclosure, determining a priority between A and B may be variously referred to as selecting one with higher priority according to a predetermined priority rule and performing a corresponding operation or omitting or dropping an operation for one with a lower priority.
Hereinafter, in the disclosure, the examples are described through a plurality of embodiments, but they are not independent, and one or more embodiments may be applied simultaneously or in combination.
Embodiment 1 of the disclosure describes a method of configuring higher layer signaling and instructing L1 signaling for PUSCH repetition transmission considering multiple TRPs. PUSCH repetition transmission considering multiple TRPs may be operated through single or multi-DCI-based instruction, and will be described in each of Embodiments 1-1 and 1-2. Further, in Embodiment 1-3 of the disclosure, a configured grant PUSCH repetition transmission method considering multiple TRPs will be described. Further, in Embodiment 1-4 of the disclosure, a method of configuring an SRS resource set for PUSCH repetition transmission considering multiple TRPs will be described.
As an embodiment of the disclosure, in Embodiment 1-1, a PUSCH repetition transmission method considering single DCI-based multiple TRPs will be described. The UE may report that a PUSCH repetition transmission method considering single DCI-based multiple TRPs is possible through UE capability reporting. The base station may configure which PUSCH repetition transmission method is to be used for the UE that has reported the corresponding UE capability (e.g., UE capability supporting PUSCH repetition transmission considering single DCI-based multiple TRPs) through higher layer signaling. In this case, higher layer signaling may be configured by selecting one of two of a PUSCH repetition transmission type A and a PUSCH repetition transmission type B.
In Rel-15/16, in the case of a PUSCH repetition transmission method considering a single TRP, both codebook and non-codebook based transmission methods were performed based on single DCI. When transmitting a codebook-based PUSCH, the UE may apply the same value to each PUSCH repetition transmission using an SRI or TPMI indicated by one DCI. Further, when transmitting a non-codebook based PUSCH, the UE may apply the same value to each PUSCH repetition transmission using an SRI indicated by one DCI. For example, when codebook-based PUSCH transmission and PUSCH repetition transmission type A is configured by higher layer signaling, and a time resource allocation index in which the number of PUSCH repetition transmissions is configured to 4, an SRI index 0, and a TPMI index 0 are instructed through DCI, the UE applies both an SRI index 0 and a TPMI index 0 to each of four PUSCH repetition transmissions. Here, the SRI may be related to a transmission beam, and the TPMI may be related to a transmission precoder. Unlike the PUSCH repetition transmission method considering a single TRP, a PUSCH repetition transmission method considering multiple TRPs may should differently apply a transmission beam and transmission precoder to transmission to each TRP. Accordingly, the UE may perform PUSCH repetition transmission considering multiple TRPs by receiving a plurality of SRIs or TPMIs indicated through DCI and applying them to each PUSCH repetition transmission.
In the case of instructing a PUSCH repetition transmission method considering single DCI-based multiple TRPs to the UE, methods of indicating a plurality of SRIs or TPMIs in the case that the PUSCH transmission method is a codebook or non-codebook may be considered as follows.
[Method 1] Transmission of Single DCI with a Plurality of SRI or TPMI Fields
In order to support a PUSCH repetition transmission method considering single DCI-based multiple TRPs, the base station may transmit DCI having a plurality of SRI or TPMI fields to the UE. Such DCI has a new format (e.g., DCI format 0_3) or an existing format (e.g., DCI format 0_1, 0_2), but when additional higher layer signaling (e.g., signaling capable of distinguishing whether a plurality of SRI or TPMI fields may be supported) is configured and the corresponding configuring exists, the DCI may be DCI in which a plurality of SRI or TPMI fields, which has previously existed only one, exist. For example, in the case that codebook-based PUSCH transmission is configured by higher layer signaling, when higher layer signaling capable of distinguishing whether a plurality of SRI or TPMI fields may be supported is configured, the UE may receive DCI of a new format or an existing format having two SRI fields and two TPMI fields to perform codebook-based PUSCH repetition transmission considering multiple TRPs. As another example, in the case that non-codebook-based PUSCH transmission is configured by higher layer signaling, when the UE is configured with higher layer signaling capable of distinguishing whether a plurality of SRI or TPMI fields may be supported, the UE may receive DCI of a new format or an existing format having two SRI fields to perform non-codebook based PUSCH repetition transmission considering multiple TRPs. For all of the above-described codebook and non-codebook based PUSCH transmissions, when a plurality of SRI fields are used, an SRS resource set in which usage, which is higher layer signaling is configured to a codebook or non-codebook may be configured to two or more, each SRI field may indicate an SRS resource, and each SRS resource may be included in two different SRS resource sets. Details on the plurality of SRS resource sets will be described in detail in Embodiment 1-4.
[Method 2] Transmission of DCI to which Enhanced SRI and TPMI Fields are Applied
In order to support a PUSCH repetition transmission method considering single DCI-based multiple TRPs, the UE may receive a MAC-CE for supporting an enhanced SRI or TPMI field from the base station. The corresponding MAC-CE may contain information instructing to change the interpretation of a codepoint of a DCI field to indicate a plurality of transmission beams for a specific codepoint of an SRI field in the DCI or to indicate a plurality of transmission precoders for a specific codepoint of a TPMI field. The following two methods for indicating a plurality of transmission beams may be considered.
Reception of an MAC-CE activating a specific codepoint of the SRI field to indicate one SRS resource to which a plurality of SRS spatial relation info is connected
Reception of an MAC-CE activating a specific codepoint of the SRI field to indicate a plurality of SRS resources to which one SRS spatial relation info is connected
In the case that a plurality of SRS resources are indicated using an enhanced SRI field, because a transmission power control parameter of the SRS resource is configured for each SRS resource set, in order to configure different transmission power control parameters for each TRP, each SRS resource may exist in a different SRS resource set. Accordingly, there may be two or more SRS resource sets in which usage, which is higher layer signaling, is configured to a codebook or non-codebook.
As an embodiment of the disclosure, in Embodiment 1-2, a PUSCH repetition transmission method considering multi-DCI-based multiple TRPs will be described. As described above, because all PUSCH repetition transmission methods in Rel-15/16 is a method considering a single TRP, it was possible that a transmission beam, transmission precoder, resource allocation, and power control parameters use the same values for each repetition transmission. However, in the case of PUSCH repetition transmission considering multiple TRPs, different parameters may need to be applied for each TRP for PUSCH transmission related parameters configured by higher layer signaling or indicated by DCI for each PUSCH repetition transmission to multiple TRPs. For example, in the case that multiple TRPs exist in different directions from the UE, because transmission beams or transmission precoders may be different, transmission beams or transmission precoders for each TRP need to be configured or indicated, respectively. As another example, in the case that multiple TRPs exist at different distances from the UE, independent power control schemes between the multiple TRPs and the UE may be required; thus, different time/frequency resource allocations may be made. For example, in order to increase power per RE, a relatively small number of RBs and a large number of symbols may be allocated to a TRP existing in a relatively distant distance compared to a specific TRP. Therefore, in order to transmit different information to the UE through single DCI, a bit length of the corresponding DCI may be very large; thus, it may be more efficient to instruct PUSCH repetition transmission to the UE through a plurality of DCIs.
The UE may report that a PUSCH repetition transmission method considering multi-DCI-based multiple TRPs is possible through UE capability reporting. For the UE that has reported a corresponding UE capability (e.g., UE capability supporting PUSCH repetition transmission considering multi-DCI-based multiple TRPs), the base station may notify the UE to perform PUSCH repetition transmission considering multiple TRPs through multi-DCI using a configuration through higher layer signaling, an indication through L1 signaling, or a configuration and instruction through a combination of higher layer signaling and L1 signaling. The base station may use a method of configuring or instructing PUSCH repetition transmission considering multi-DCI-based multiple TRPs as follows.
When performing PUSCH repetition transmission considering multi-DCI-based multiple TRPs, the UE may expect different time/frequency resource allocation information indicated by each DCI in consideration of TRPs of different distances from the UE. The UE may report to the base station whether different time/frequency resources may be allocated with the UE capability. The base station may configure whether to allocate different time/frequency resources to the UE by higher layer signaling, and the UE that has received the corresponding configuration may expect different time/frequency resource allocation information to be instructed from each DCI. In this case, the UE may receive a configuration or an instruction from the base station for PUSCH repetition transmission considering multi-DCI-based multiple TRPs in consideration of a higher layer signaling configuration and conditions between a plurality of DCI fields. In the case that transmitting beam and transmission precoder information is instructed through multi-DCI, SRI and TPMI in DCI received first may be applied first when applying to the transmission beam mapping method of Embodiment 2, and SRI and TPMI in DCI received second may be applied second when applying to the transmission beam mapping method of Embodiment 2.
The base station may configure a CORESETPoolIndex, which is higher layer signaling, for each CORESET to the UE, and when receiving a certain CORESET, the UE may know from which TRP the corresponding CORESET is transmitted. For example, when a CORESETPoolIndex is configured to 0 in a CORESET #1 and a CORESETPoolIndex is configured to 1 in a CORESET #2, the UE may know that the CORESET #1 is transmitted from TRP #0 and that the CORESET #2 is transmitted from TRP #1. Further, the fact that DCI transmitted in each CORESET in which the CORESETPoolIndex value is configured to 0 and 1 indicates the repeated PUSCH may be implicitly indicated by a condition between specific fields in a plurality of transmitted DCI. For example, in the case that HARQ process number field values in the plurality of DCI transmitted by the base station to the UE are the same and that NDI field values are the same, the UE may regard implicitly that each of the corresponding plurality of DCI schedules the repeated PUSCH in consideration of the multiple TRPs. In the case that the HARQ process number field value is the same and that the NDI field value is the same, there may be restrictions on reception of a plurality of DCI. For example, the maximum interval between the plurality of DCI receptions may be defined within the number of one or more specific slots or one or more specific symbols. In this case, the UE may perform PUSCH transmission based on the minimum transport block size calculated (or identified) based on time/frequency resource allocation information indicated differently in a plurality of DCI.
As an embodiment of the disclosure, in Embodiments 1-3, a configured grant PUSCH repetition transmission method considering multiple TRPs will be described. The UE may report to the base station with a UE capability whether to repeatedly transmit a configured grant PUSCH considering multiple TRPs. For configured grant PUSCH repetition transmission considering multiple TRPs, the base station may configure to the UE by higher layer signaling, instruct to the UE by L1 signaling, or configure and instruct to the UE using a combination of higher layer signaling or L1 signaling using the following various methods.
Method 1 is a method of indicating a plurality of SRIs or TPMIs based on the single DCI to the UE, and activating a single configured grant configuration along with the corresponding indication. A method of indicating a plurality of SRIs or TPMIs with single DCI may follow a method of Embodiment 1-1, and when there is only one configured grant configuration for the UE, all bits of a HARQ process number field and a redundancy version field in the corresponding DCI may be indicated as 0. When a plurality of configured grant configurations exist for the UE and one of the plurality of configured grant configurations is activated by the corresponding DCI, a HARQ process number field in the corresponding DCI may indicate an index of the configured grant configuration, and all bits in a redundancy version field may be indicated as 0. The UE may map a transmission beam and a transmission precoder to each activated configured grant PUSCH repetition transmission using a plurality of SRIs or TPMIs indicated by single DCI according to a transmission beam mapping method in the following Embodiment 2.
Method 2 is a method of indicating each SRI or TPMI with each DCI to the UE based on the above multi-DCI, and activating a single configured grant configuration along with the corresponding indication. A method of indicating each SRI or TPMI with each DCI based on multi-DCI may follow the method of the Embodiment 1-2, and when there is only one configured grant configuration for the UE, all bits of all HARQ process number fields and the redundancy version field in the corresponding multi-DCI may be indicated as 0. When a plurality of configured grant configurations exist for the UE and one of the plurality of configured grant configurations is activated by the corresponding multi-DCI, all HARQ process number fields in the multi-DCI may indicate an index of the same configured grant configuration, and all bits of all redundancy version fields within the multi-DCI may be indicated as 0. According to a condition of the DCI field in the above multi-DCI-based PUSCH repetition transmission, it is characterized that the NDI field in addition to the HARQ process number field has the same value. The UE may map a transmission beam and a transmission precoder to each activated configured grant PUSCH repetition transmission using a plurality of SRIs or TPMIs indicated by multi-DCI according to the transmission beam mapping method described below. For example, when a transmission beam and transmission precoder related information indicated by first received DCI are SRI #1 and TPMI #1, respectively, a transmission beam and transmission precoder related information indicated by second received DCI are SRI #2 and TPMI #2, respectively, and a transmission beam mapping method configured by higher layer signaling is cyclical, by applying SRI #1 and TPMI #1 to odd-numbered transmissions (1, 3, 5, . . . ) of the activated configured grant PUSCH repetition transmission and SRI #2 and TPMI #2 to even-numbered transmissions (2, 4, 6, . . . ) of repetition transmission, the UE may perform PUSCH transmission.
Method 3 is a method of indicating each SRI or TPMI with each DCI to the UE based on the above multi-DCI, and activating multiple configured grant configurations together with the corresponding indication. A method of indicating each SRI or TPMI with each DCI based on multi-DCI may follow a method of the above Embodiment 1-2, a plurality of configured grant configurations exist for the UE, and an index of each configured grant configuration may be indicated through a HARQ process number field in each DCI. Further, all bits of all redundancy version fields in the corresponding multi-DCI may be indicated as 0. According to a condition of a DCI field in the above multi-DCI-based PUSCH repetition transmission, it is characterized that an NDI field in addition to the HARQ process number field has the same value. The UE may receive MAC-CE signaling instructing (commanding) connection between a plurality of configured grant configurations activated by multi-DCI. The UE may receive multi-DCI from the base station 3 ms after performing HARQ-ACK transmission for MAC-CE signaling, and when a configured grant configuration index indicated in each DCI matches configured grant configuration indexes that receive an instruction (command) of connection through the above MAC-CE signaling, the UE may perform PUSCH repetition transmission considering multiple TRPs based on the instructed configured grant configurations. In this case, some configurations may be shared with the same value between a plurality of connected configured grant configurations. For example, repK, which is higher layer signaling that means the number of repetition transmissions, repK-RV, which is higher layer signaling that means the order of a redundancy version in repetition transmission, and periodicity, which is higher layer signaling that means a period of repetition transmission may be configured to have the same value in the connected configured grant configuration.
As an embodiment of the disclosure, in Embodiment 1-4, a method of configuring an SRS resource set for PUSCH repetition transmission considering multiple TRPs will be described. Because power control parameters of an SRS (e.g., alpha, p0, pathlossReferenceRS, srs-PowerControlAjdustmentStates, and the like that may be configured by higher layer signaling) may vary for each SRS resource set, when repeatedly transmitting a PUSCH considering multiple TRPs, for different power control of an SRS for each TRP, the number of SRS resource sets may be increased to two or more, and different SRS resource sets may be used for the purpose of supporting different TRPs. An SRS resource set configuration method considered in this embodiment may be applied to the above Embodiments 1-1 to 1-3.
When performing PUSCH repetition transmission considering single DCI-based multiple TRPs, a plurality of SRIs indicated by single DCI may be selected from SRS resources existing in different SRS resource sets. For example, when two SRIs are indicated by single DCI, a first SRI may be selected from an SRS resource set #1, and a second SRI may be selected from an SRS resource set #2.
When repeatedly transmitting a PUSCH considering multi-DCI-based multiple TRPs, each SRI indicated by each of two DCIs may be selected from SRS resources existing in different SRS resource sets, and each SRS resource set may be explicitly or implicitly connected (correspond) with higher layer signaling (e.g., CORESETPoolIndex) meaning each TRP. As a method of explicitly connecting, a quasi-static connection state between the CORESET and the SRS resource set may be notified to the UE by configuring a CORESETPoolIndex value in a configuration of the SRS resource set configured to the higher layer. As another example, as a more dynamic and explicit connection method, a MAC-CE that activates a connection between a specific CORESET (including all cases that a value of CORESETPoolIndex is configured to 0, 1, or not configured) and the SRS resource set may be used. After receiving an MAC-CE that activates a connection between a specific CORESET (including all cases that a CORESETPoolIndex value is configured to 0, 1, or not configured) and the SRS resource set, the UE may transmit HARQ-ACK and regard that the connection between the corresponding CORESET and the SRS resource set has been activated from after 3 ms. As an implicit method, an implicit connection state is assumed using a specific criterion between the CORESETPoolIndex and an index of the SRS resource set. For example, assuming that the UE is configured with two SRS resource sets #0 and #1, the UE may assume that the CORESETPoolIndex is not configured or a SRS resource set #0 set was connected with a CORESET configured to 0 and that a SRS resource set #1 was connected to a CORESET in which the CORESETPoolIndex is configured to 1.
For the above single or multi-DCI-based methods, the UE that has explicitly or implicitly configured or indicated with a connection between different SRS resource sets and each TRP may expect to configure sameAsFci2 to a srs-PowerControlAdjustmentStates value configured by higher layer signaling in each SRS resource set and may not expect to configure to separateClosedLoop. Further, it may be expected that the usage configured by higher layer signaling within each SRS resource set is equally configured to a codebook or noncodebook.
As an embodiment of the disclosure, in Embodiment 1-5, a dynamic switching method for determining PUSCH transmission considering a single TRP or PUSCH transmission considering multiple TRPs based on a codebook will be described.
From a UE capable of performing codebook-based PUSCH repetition transmission in consideration of single DCI-based multiple TRPs according to the above Embodiments 1-1 and 1-4, the base station may receive UE capability reporting from the UE and configure higher layer signaling for performing PUSCH repetition transmission through multiple TRPs to the UE. In this case, when performing PUSCH repetition transmission in consideration of single DCI-based multiple TRPs as in the Embodiment 1-4, in order to indicate SRS resources existing in different SRS resource sets, the base station may transmit single DCI including a plurality of SRI fields to the UE. In this case, each of the plurality of SRI fields may be interpreted in the same method as that in NR Release 15/16. More specifically, a first SRI field may select an SRS resource from a first SRS resource set, and a second SRI field may select an SRS resource from a second SRS resource set. Similar to a plurality of SRI fields, in order to repeatedly transmit a PUSCH in consideration of multiple TRPs, the base station may transmit single DCI including a plurality of TPMI fields to the UE so that each TPMI corresponding to the SRS resource indicated by each SRI field may be selected. In this case, the plurality of TPMI fields may be indicated through the same DCI as that including the above-described plurality of SRI fields. A plurality of TPMIs to be used upon PUSCH transmission to each TRP may be selected through the following methods using a plurality of TPMI fields:
[Method 1] Each TPMI field may be interpreted in the same method as that in NR Release 15/16. For example, the first TPMI field may indicate a TPMI index and layer information on the SRS resource indicated by a first SRI field, and the second TPMI field may indicate a TPMI index and layer information on the SRS resource indicated by a second SRI field. In this case, the first TPMI field and the second TPMI field may indicate the same layer information.
[Method 2] The first TPMI field may indicate a TPMI index and layer information on the SRS resource indicated by the first SRI field in the same method as that in NR Release 15/16. In contrast, because the second TPMI field selects a TPMI index for the same layer as that indicated by the first TPMI field, the second TPMI field may not indicate layer information, but may indicate TPMI index information on an SRS resource indicated by the second SRI field.
In the case that a plurality of TPMIs are selected through the method 2, a bit length of the second TPMI field may be smaller than that of the first TPMI field. This is because the second TPMI field indicates one value (index) of the same TPMI index candidates as those of the layer indicated by the first TPMI field, the second TPMI field may not indicate layer information.
The UE may receive single DCI including a plurality of SRI fields and a plurality of TPMI fields, and support a dynamic switching method of determining PUSCH repetition transmission considering multiple TRPs or PUSCH repetition transmission considering a single TRP based on this. The UE may support dynamic switching using a reserved value that does not have any meaning among values that may have a plurality of TPMI fields or SRI fields included in the received DCI. For example, when a bit length of the SRI field is 2 bits, total 4 cases may be expressed, and in this case, each expressible case may be defined to a codepoint. Further, in the case that three codepoints among total four codepoints have a meaning on which SRI to indicate and that the remaining one codepoint do not have any meaning, this codepoint may be a codepoint indicating a reserved value. (In the following description, a codepoint indicating a reserved value may be expressed as being configured as reserved). It will be described in more detail through the contents to be described later.
In order to describe a dynamic switching method in which a plurality of TPMI fields may be supported through a reserved value as a specific example, it is assumed that a PUSCH antenna port is 4. Further, it is assumed that the first TPMI field is composed of 6 bits, a higher layer parameter codebookSubset is configured to fullyAndPartialAndNonCoherent and that it is indicated in the same method as that of NR Release 15/16. In this case, in the first TPMI field, indexes 0 to 61 may be configured to indicate valid TPMI indexes and layer information, and indexes 62 to 63 may be configured to reserved. When the second TPMI field includes only TPMI index information excluding layer information as in the above method 2, the second TPMI field may indicate only a TPMI index of the case that a layer for PUSCH transmission is limited to one value (e.g., one value of 1 to 4) according to the first TPMI field. In this case, the number of bits of the second TPMI field may be configured based on the number of bits capable of representing a layer with the most candidates among TPMI index candidates that may be configured for each layer. For example, according to an example in which a layer 1 has candidates from 0 to 27, a layer 2 has candidates from 0 to 21, a layer 3 has candidates from 0 to 6, and a layer 4 has candidates from 0 to 4, the layer 1 has the most candidates. Accordingly, the number of bits of the second TPMI field may be configured to 5 according to the number of TPMI index candidates of the layer 1. When a second TPMI field constitution is described in detail, in the case that the first TPMI field indicates 1 layer and the corresponding TPMI index, the UE may interpret the second TPMI field to a codepoint indicating a value of one of TPMI indexes 0 to 27 for 1 layer and a codepoint indicating a reserved value. For example, in the case that the first TPMI field indicates 2 layer and the corresponding TPMI index, the UE may interpret the second TPMI field to a codepoint indicating a value of one of TPMI indexes 0 to 21 for 2 layer and a codepoint indicating a reserved value. Further, for example, in the case that the first TPMI field indicates 3 or 4 layer and the corresponding TPMI index, the UE may interpret the second TPMI field similarly to the above. In this case, in the case that there are two or more codepoints indicating a reserved value in addition to the codepoint indicating a TPMI index in the second TPMI field, codepoints indicating two reserved values may be used for indicating dynamic switching. That is, among codepoints of the second TPMI field composed of 5 bits, the second to last codepoint (i.e., the 31st codepoint in the example) corresponding to a codepoint indicating a reserved value may be used for indicating PUSCH repetition transmission considering a single TRP with the first TRP, and the last codepoint (i.e., the 32nd codepoint in the example) may be used for indicating PUSCH repetition transmission considering a single TRP with the second TRP. In this case, the UE may receive an indication of layer information and TPMI index information for PUSCH repetition transmission considering a single TRP by the first TPMI field. The assumption as described above is for convenience of description, but the disclosure is not limited thereto.
For convenience of description, when the specific example for two TRPs is generalized and described, the UE may receive single DCI including two SRI fields and two TPMI fields, and perform dynamic switching according to a codepoint indicated by the second TPMI field. When a codepoint of the second TPMI field indicates a TPMI index for a layer indicated by the first TPMI field, the UE may perform PUSCH repetition transmission considering multiple TRPs. When the second TPMI field indicates a second to last codepoint corresponding to a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 1 and identify layer information and TPMI index information for codebook-based PUSCH transmission from the first TPMI field. When the second TPMI field indicates a last codepoint corresponding to a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 2, and identify layer information for codebook-based PUSCH transmission and TPMI index information from the first TPMI field.
The above-described example used two reserved codepoints at the end of the second TPMI field in order to indicate dynamic switching, but this embodiment is not limited thereto. That is, dynamic switching may be indicated using codepoints indicating two other reserved values of the second TPMI field, and PUSCH repetition transmission considering a single TRP for the TRP 1 or PUSCH repetition transmission considering a single TRP for the TRP 2 may be indicated by mapping to a codepoint indicating each reserved value.
Further, the above-described example describes the case that the second TPMI field is determined by the method 2, but even in the case that the second TPMI field is determined identically to NR Release 15/16 as in the method 1, dynamic switching may be supported using the reserved codepoints of TPMI with the same method with that of the above-described example.
For example, in the case that the number of codepoints indicating a reserved value of the second TPMI field is smaller than 2, the number of bits of the second TPMI field is increased by 1, and the second to last codepoint and the last codepoint based on the increased number of bits may be used for supporting dynamic switching.
In the case that two TPMI fields are determined as in the method 1, a method of supporting dynamic switching according to whether each TPMI field was indicated by a codepoint indicating a reserved value may be additionally considered. That is, when a first TPMI field is indicated with a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 2, and when the second TPMI field is indicated with a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 1. When both TPMI fields indicate codepoints for TPMIs other than codepoints indicating reserved values, the UE may perform PUSCH repetition transmission considering multiple TRPs. When a codepoint having a reserved value does not exist, the UE may increase the number of bits in the TPMI field by 1, and use a last codepoint based on the increased number of bits for supporting dynamic switching.
As another method of supporting dynamic switching, the UE may indicate dynamic switching with two SRI fields and identify layer information and TPMI index information for PUSCH repetition transmission considering multiple TRPs or single TRP from two TPMI fields. When one or more codepoints indicating a reserved value exist in each SRI field, the UE may support dynamic switching according to whether the corresponding SRI field indicates a codepoint indicating a reserved value. When the first SRI field indicates a codepoint indicating a reserved value and the second SRI field indicates an SRS resource of the second SRS resource set, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 2. In this case, in order to perform PUSCH repetition transmission considering a single TRP for the TRP 2, the UE may identify layer information and TPMI index information from the first TPMI field. When the second SRI field indicates a codepoint indicating a reserved value and the second SRI field indicates an SRS resource of the second SRS resource set, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 1. In this case, in order to perform PUSCH repetition transmission considering a single TRP for the TRP 1, the UE may identify layer information and TPMI index information from the first TPMI field. When both SRI fields indicate a SRS resource of each SRS resource set rather than a codepoint indicating the reserved value, the UE may perform PUSCH repetition transmission considering multiple TRPs. In this case, the UE may identify layer information and TPMI index information from a first TPMI field in order to perform PUSCH repetition transmission for the TRP 1 and identify TPMI index information from a second TPMI field in order to perform PUSCH repetition transmission for the TRP 2. In this case, when a PUSCH for the TRP 1 and the TRP 2 is transmitted, the layer may be configured identically. When a codepoint indicating a reserved value does not exist in two SRI fields, the UE may increase the number of bits of each SRI field by 1 and use a last codepoint among codepoints indicating a reserved value for supporting dynamic switching based on the increased number of bits.
As an embodiment of the disclosure, in Embodiments 1-6, a dynamic switching method for determining PUSCH transmission considering a single TRP or PUSCH transmission considering multiple TRPs based on a non-codebook will be described.
According to the above Embodiments 1-1 and 1-4, the base station may receive UE capability reporting from a UE capable of performing non-codebook-based PUSCH repetition transmission in consideration of single DCI-based multiple TRPs and configure higher layer signaling for performing PUSCH repetition transmission through multiple TRPs to the UE. In this case, when performing PUSCH repetition transmission in consideration of single DCI-based multiple TRPs, as in Embodiment 1-4, in order to indicate SRS resources existing in different SRS resource sets, the base station may transmit single DCI including a plurality of SRI fields to the UE. A plurality of SRI fields may be selected according to, for example, the following method.
[Method 1] Each SRI field may be selected in the same method as that in NR Release 15/16. For example, a first SRI field may indicate an SRS resource for PUSCH transmission in a first SRS resource set, and a second SRI field may indicate an SRS resource for PUSCH transmission in a second SRS resource set. In this case, the first SRI field and the second SRI field may indicate the same layer information.
[Method 2] The first SRI field may indicate an SRS resource(s) for PUSCH transmission in the first SRS resource set in the same method as that in NR Release 15/16. The second SRI field may indicate an SRS resource(s) for PUSCH transmission in the second SRS resource set for the same layer as that indicated by the first SRI field.
In the case that a plurality of SRIs are selected through the method 2, a bit length of the second SRI field may be smaller than that of the first SRI field. This is because the second SRI is determined among SRI candidates for the same layer as that determined by the first SRI field among SRI candidates for all supportable layers.
The UE may receive single DCI including a plurality of SRIs and support a dynamic switching method of determining PUSCH repetition transmission considering multiple TRPs or PUSCH repetition transmission considering a single TRP based on this. The UE may support dynamic switching using codepoints indicating reserved values of a plurality of SRI fields included in the received DCI.
In order to describe a dynamic switching method that may be supported through codepoints indicating reserved values of a plurality of SRI fields as a specific example, it is assumed that the number of PUSCH antenna ports is maximum 4 and that the number of SRS resources in each SRS resource set is 4. Further, it is assumed that the first SRI field is composed of 4 bits and is indicated in the same method as that in NR Release 15/16. In this case, in a first SRI area, indexes 0 to 14 may be configured to indicate a layer according to a selected SRS resource and an SRS resource for PUSCH transmission, and an index 15 may be configured to a codepoint indicating a reserved value. When the second SRI field selects the same number of SRS resources as the number of layers indicated by the first SRI as in the above method 2, the second SRI field may indicate an SRS resource selection candidate of the case that a layer for PUSCH transmission is limited to one value (e.g., a value of one of 1 to 4) according to the first SRI field. In this case, the number of bits of the second SRI field may be configured based on a layer having the largest number of candidates among the number of SRS resource selection candidates for each layer. For example, there may be total 4 candidates as SRI field values of 0 to 3 indicating SRS resource selection candidates for a layer 1, and there may be total 6 candidates as SRI field values of 4 to 9 indicating SRS resource selection candidates for a layer 2, there may be total 4 candidates as SRI field values of 10 to 13 indicating SRS resource selection candidates for a layer 3, and there may be total 1 candidate as a SRI field value of 14 indicating SRS resource selection candidates for a layer 4. In this case, because the number of candidates for the layer 2 has the largest value as total 6, the number of bits of the second SRI field may be configured to 3. When a constitution of the second SRI field is described in detail, in the case that the SRI value is indicated when a layer for PUSCH transmission with the first SRI field is 1, the UE may interpret the second SRI field to a codepoint indicating one value of SRI candidates 0 to 3 for 1 layer or another value to a codepoint having a reserved value. For example, in the case that an SRI value is indicated when a layer for PUSCH transmission with the first SRI field is 2, the UE may interpret the second SRI field to a codepoint indicating one of SRI candidates 0 to 5 for 2 layer or another value to a codepoint having a reserved value. Further, for example, in the case of indicating an SRI value when a layer for PUSCH transmission with the first SRI field is 3 or 4, the UE may interpret the second SRI field in a similar method. In this case, in the case that there are two or more codepoints indicating reserved values in addition to codepoints indicating SRI values according to layers in the second SRI field, codepoints indicating two reserved values may be used for indicating dynamic switching. That is, among codepoints of the second SRI field composed of 3 bits, the second to last codepoint (i.e., the 7th codepoint in the example) corresponding to a codepoint indicating a reserved value may be used for indicating PUSCH repetition transmission considering a single TRP with a first TRP, and the last codepoint (i.e., the 8th codepoint in the example) may be used for indicating PUSCH repetition transmission considering a single TRP with a second TRP. In this case, the UE may receive an indication of an SRI for PUSCH repetition transmission considering a single TRP with the first SRI field. The assumption as described above is for convenience of description, but the disclosure is not limited thereto.
For convenience of description, when the above specific example for two TRPs is generalized and described, the UE may receive single DCI including two SRI fields and perform dynamic switching according to a codepoint indicated by the second SRI field. When the codepoint of the second SRI field indicates an SRI value for a layer indicated by the first SRI field, the UE may perform PUSCH repetition transmission considering multiple TRPs. When the second SRI field indicates the second to last codepoint corresponding to a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 1, and identify a SRI for non-codebook based PUSCH transmission from the first SRI field. When the second SRI field indicates a last codepoint corresponding to the codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 2 and identify an SRI for non-codebook based PUSCH transmission from the first SRI field.
In the above-described example, codepoints indicating two reserved values at the end of the second SRI field were used for indicating dynamic switching, but this embodiment is not limited thereto. That is, dynamic switching may be indicated using codepoints indicating two other reserved values of the second SRI field, and PUSCH repetition transmission considering a single TRP for the TRP 1 or PUSCH repetition transmission considering a single TRP for the TRP 2 may be indicated by mapping to a codepoint indicating each reserved value.
Further, the above-described example described the case that the second SRI field is determined by the method 2, but even in the case that the second SRI field is determined identically to NR Release 15/16 as in the method 1, dynamic switching may be supported using a codepoint indicating a reserved value of the SRI field with the same method as that in the above example.
For example, in the case that the number of codepoints indicating a reserved value of the second SRI field is smaller than 2, the number of bits of the second SRI field is increased by 1, and the second to last codepoint and the last codepoint based on the increased number of bits may be used for supporting dynamic switching.
In the case that two SRI fields are determined as in the method 1, a method of supporting dynamic switching according to whether each SRI field is indicated by a codepoint indicating a reserved value may be additionally considered. That is, when the first SRI field is indicated by a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 2, and when the second SRI field is indicated by a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering a single TRP for the TRP 1. When both SRI fields indicate a codepoint for indicating an SRI rather than a codepoint indicating a reserved value, the UE may perform PUSCH repetition transmission considering multiple TRPs. When a codepoint indicating a reserved value does not exist, the number of bits in a SRI area is increased by 1, and a last codepoint based on the increased number of bits may be used for supporting dynamic switching.
With reference to
As an embodiment of the disclosure, the UE may perform UE capability reporting by defining a time interval (e.g., which may be expressed as a transient period, a transient offset, a transient gap, and the like) that may be required between a plurality of uplink transmissions or may be configured from the base station, and apply a corresponding time interval between each uplink transmission when transmitting an uplink signal considering this. In order to transmit an uplink signal, the UE may change at least one of an uplink beam, transmission power, or frequency before signal transmission. Further, in order to transmit an uplink signal, the UE may change a panel before signal transmission. Accordingly, in order to transmit an uplink signal, the UE may change at least one of an uplink beam, transmission power, frequency, or panel before signal transmission. Here, for example, in the case of dividing a plurality of beams into a plurality of beam groups, a panel corresponding to each beam group may be configured, such as a panel #1 for a beam group #1, a panel #2 for a beam group #2, . . . . As another example, in the case that the panel includes a plurality of antenna modules for forming a beam in the UE and that the plurality of antenna modules are installed in different locations, a panel corresponding to each antenna module may be configured. Further, a plurality of panels may be configured in various manners capable of distinguishing a plurality of beams having different beam widths, beam directions, and the like. Changes for transmission of such uplink signals may be performed in the following cases:
Case 1) In the case that an uplink signal (e.g., PUCCH, PUSCH, or SRS) is repeatedly transmitted to a plurality of TRPs, when the UE changes an uplink beam, transmission power, or frequency in order to change and transmit the TRP between repetition transmissions or when the UE changes the panel in order to change and transmit the TRP between repetition transmissions
Case 2) In the case that the base station instructs transmission of an uplink signal by MAC CE signaling or L1 signaling including DCI, when the UE changes an uplink beam, transmission power, or frequency in order to transmit an uplink signal or when the UE changes a panel in order to transmit uplink signals
Case 3) When SRS transmission is instructed or configured, when a plurality of SRS resources included in the SRS resource set are used, when an uplink beam, transmission power, or frequency is changed in order to use a plurality of SRS resource sets, or when the UE changes a panel for SRS transmission
In Case 1, the case of changing the transmission information in order to change a TRP between repetition transmissions may be determined according to a mapping pattern between repetition transmission and TRP. Here, repetition transmission means, for example, the case of transmitting the same uplink signal. In the 3GPP Release 16 standard, when the base station repeatedly transmits a PDSCH, the base station supports two mapping patterns (e.g., ‘Sequential’ and ‘Cyclical’). A mapping pattern for repeatedly transmitting the PDSCH to a plurality of TRPs may be applied when the UE repeatedly transmits uplink signals to a plurality of TRPs. ‘Sequential’ mapping is a method of changing and transmitting a TRP in two repetition transmission units, for example, as in {TRP1, TRP1, TRP2, TRP2}, and ‘cyclical’ mapping is a method of changing and transmitting a TRP for every repetition transmission, for example, as in {TRP1, TRP2, TRP1, TRP2}. When at least one of an uplink beam for transmitting an uplink signal to a plurality of TRPs, transmission power, or frequency (or frequency hop) to transmit is determined, the UE may apply uplink transmission change information determined according to a mapping method to transmit an uplink signal. Alternatively, when a panel for transmitting an uplink signal to a plurality of TRPs is determined, by applying uplink transmission change information determined according to the mapping method, the UE may transmit an uplink signal. Here, the uplink transmission change information may mean at least one of an uplink beam for transmitting an uplink signal, transmission power, or a frequency to transmit. Alternatively, the uplink transmission change information may mean a panel for transmitting an uplink signal. When the PUSCH is repeatedly transmitted to a plurality of TRPs, for example, both a PUSCH repetition transmission type A and a PUSCH repetition transmission type B may be included. The PUSCH repetition transmission type B may consider both nominal repetition and actual repetition in a repetition transmission unit.
In Case 2, the base station may configure a higher layer parameter for uplink signal transmission to the UE and instruct the UE to transmit an uplink signal (e.g., PUCCH, PUSCH, or SRS) through L1 signaling (e.g., DCI). In this case, a time interval between signaling instructing to transmit an uplink signal to the UE by the base station and an uplink signal transmitted by the UE is defined to ‘time offset’, which may be replaced with a ‘scheduling interval’, ‘scheduling offset’, ‘time interval’, ‘transient period’, ‘transient offset’, ‘transient time’, and the like. In the case that the base station instructs to transmit an uplink signal to the UE by L1 signaling including DCI, the time offset may be calculated from a last symbol in which a PDCCH including DCI is transmitted and before a first symbol in which an ‘uplink (e.g., PUCCH including HARQ-ACK for aperiodic/semi-persistent SRS, PUSCH, or PDSCH) is transmitted. In the case that a DCI decoding time of the UE is additionally considered, the time offset may be calculated as ‘after a last symbol in which a PDCCH including DCI is transmitted and before a first symbol in which an uplink signal is transmitted’. In the case that the base station instructs transmission of an uplink signal through MAC CE signaling, the time offset may be calculated by the following method.
Method 1: between the end of a last symbol in which a PDSCH including MAC CE signaling is transmitted and before the start of a first symbol in which an uplink signal (e.g., aperiodic/semi-persistent SRS) is transmitted
Method 2: between the end of a last symbol in which a PUCCH/PUSCH including a HARQ-ACK for a PDSCH including MAC CE signaling is transmitted and before the start of a first symbol in which an uplink signal is transmitted
Method 3: between a MAC CE application delay time (e.g., until the first slot after 3 ms has elapsed) has elapsed at an end time point of a last symbol in which a PUCCH/PUSCH including a HARQ-ACK for a PDSCH including MAC CE signaling is transmitted and before the start of a first symbol in which an uplink signal is transmitted
This time offset may be converted into an absolute time unit (e.g., ms) or a symbol unit. When receiving an instruction to transmit an uplink signal from the base station, the UE may change at least one of an uplink transmission beam for transmitting an uplink beam, transmission power, or frequency during a time offset. Alternatively, the UE may change a panel for uplink transmission during the time offset.
In case 3, when the UE transmits an SRS scheduled by the base station, the UE may change and transmit an uplink beam, transmission power, and frequency according to a higher layer configuration of the SRS resource included in an SRS resource set to be transmitted. Alternatively, by changing the panel according to a higher layer configuration of the SRS resource, the UE may transmit the SRS.
The UE may require a transient time in order to change at least one of an uplink beam, transmission power, or frequency according to a UE capability. Alternatively, the UE may require a transient time in order to change a panel for uplink transmission according to a UE capability. Such a transient time may be considered, for example, in the case that repetition transmission is performed in units of long subslots or in units of short subslots. According to whether a transient time according to the UE capability is satisfied between repetition transmissions of the uplink signal or during a time offset, when transmitting the uplink signal, some or all of the determined uplink beams, transmission powers, or frequencies may be applied. As described above, a certain time may be required to change the uplink beam, transmission power, or frequency, and in order to satisfy this, an offset interval may be added between repetition transmissions or the base station may instruct to transmit an uplink signal to the UE so that the time offset is greater than a certain time for change. Alternatively, even in the case of additionally performing a panel change for uplink transmission, a certain amount of time may be required, and in order to satisfy this, an offset interval may be added between repetition transmissions or the base station may instruct to transmit an uplink signal to the UE so that the time offset is greater than a certain time for change.
Hereinafter, in the disclosure, an offset in a time domain for uplink transmission of a UE may be understood as encompassing the above time offset or a time interval between repetition transmissions of an uplink signal.
Specific examples for a method for the base station to determine an offset in a time domain for ensuring a time required for changing an uplink beam, transmission power, or frequency according to a UE capability of the disclosure, and a method for the UE to transmit an uplink signal instructed by the base station will be described in detail through Embodiments 2-1 and 2-2. The division of the following Embodiments 2-1 and 2-2 is for convenience of description, and the embodiments of the disclosure may be implemented by combining at least an embodiment as well as each.
As an example of a method of determining an offset in a time domain for transmission of an uplink signal, the UE may report UE capability information including at least one of a UE capability for performing an uplink beam change, a UE capability for performing a transmission power change, or a UE capability for performing frequency hopping to the base station. Alternatively, the three UE capabilities may be individually reported to the base station. Further, the UE may select and report some of the three UE capabilities. Further, the UE may report a representative value of UE capabilities for changing a transmission configuration of an uplink signal.
In addition, when the UE may transmit uplink signals using a plurality of panels, in step of determining a UE capability to report, a UE capability for panel change may be considered together. That is, the UE may report UE capability information including at least one of a UE capability for performing uplink beam change, a UE capability for performing transmission power change, a UE capability for performing frequency change in consideration of frequency hopping, or a UE capability for performing panel change to the base station. Alternatively, each of the four UE capabilities may be individually reported to the base station. Further, the UE may select and report some of the four UE capabilities. Further, the UE may report a representative value of UE capabilities for changing a transmission configuration of an uplink signal.
Hereinafter, UE capability and UE capability information, which are terms used interchangeably in the disclosure, may be understood as the same meaning.
This is to provide information necessary for determining an offset by the base station in the case that a part or all of an uplink beam, transmission power, or frequency is changed when an uplink signal is transmitted. In addition, when the UE supports a plurality of panels, the base station may provide information necessary for determining an offset in the case that the panel is changed. The UE may report a UE capability for each uplink beam change or transmission power or frequency change using one of the following methods. In addition, a UE capability for panel change may be reported using one of the following methods:
A UE capability for an uplink transmission configuration change of NR release 15/16 may be reported. For example, in order to report a UE capability for a beam change, the UE may configure ‘beamSwitchTiming’ to one of {14, 28, 48} as in NR Release 15/16, and report it to the base station. In order to report a UE capability for a panel change, the UE may configure ‘beamSwitchTiming’ to one of {224, 336} and report it to the base station. Here, the number representing the ‘beamSwitchTiming’ is a symbol unit, and for example, in the case that ‘beamSwitchTiming’ is configured to “224” in UE capability reporting for a panel change, it means that a processing time for beam switching in a UE capability for panel change takes as much as 224 symbols. Further, the above ‘beamSwitchTiming’ may be configured for each subcarrier spacing.
A required time for a change may be reported in symbol or absolute time units (e.g., ms).
The base station and the UE may predefine a processing time capable of indicating a processing capability. A processing time for the N number of processing capacities may be defined in advance, and a processing time may be different according to an indication of subcarrier spacing. Table 45 and Table 46 represent examples of processing times defined in advance by the base station and the UE for processing capabilities n and n_1 for changing an uplink beam, transmission power, or frequency. Here, a value of a required time area may be configured such that a relationship of, for example, {a1<a2<a3<a4} and {b1<a1, b2<a2, b3<a3} is established. The unit of a required time may be configured to a symbol or ms.
When reporting a processing time for changing at least one of an uplink beam, transmission power, or frequency as a UE capability, the UE may determine a value to report in consideration of each uplink signal. For example, when a processing time for an uplink beam change is reported as a UE capability, the UE may classify and report into a UE capability for a beam change for a PUCCH, a UE capability for a beam change for a PUSCH, and a UE capability for a beam change for an SRS. The UE may classify and report into a UE capability for transmission power change and a UE capability for frequency change according to a PUCCH, PUSCH, or SRS. When the UE reports a UE capability for changing at least one of each uplink beam, transmission power, or frequency for a PUCCH, the UE may determine in consideration of the number of PUCCH resources, the number of configured spatial relation info, the number of activated spatial relation info, and a frequency hopping configuration, and the like. When the UE reports a UE capability for each uplink beam, transmission power, and frequency change for the PUSCH, the UE may determine in consideration of a PUSCH precoding method (e.g., ‘Codebook’ or ‘Non-codebook’), the number of SRS resource sets associated with PUSCH transmission, the number of configured SRS resources in the associated SRS resource set, the relationship between PUSCH and SRS antenna ports, frequency hopping configuration, and the like. When the UE reports a UE capability for each uplink beam, transmission power, and frequency change for an SRS, the UE may determine in consideration of a SRS transmission indication method (e.g., DCI-based or MAC CE-based), SRS time axis information (e.g., periodic SRS, semi-persistent SRS, or aperiodic SRS), usage of SRS (e.g., ‘beamManagement’, ‘codebook’, ‘nonCodebook’, or ‘antennaSwitching’), the number of SRS resource sets, the number of SRS resources, and the like. In addition, when the UE supporting multiple panels reports a processing time for panel change as UE capability, the UE may determine a reporting value in consideration of an uplink signal. Alternatively, the UE may determine and report a UE capability for a change in at least one of an uplink beam, transmission power, or frequency without distinguishing a UE capability for each uplink signal. The UE may determine and report a UE capability for a panel change without distinguishing a UE capability for each uplink signal.
The UE may additionally report a UE capability for indicating whether the uplink beam, transmission power, and frequency may be changed simultaneously or sequentially. Here, the UE supporting multiple panels may report with a corresponding UE capability whether the panel may be simultaneously changed. That is, the UE may report with a corresponding UE capability whether the uplink beam, transmission power, frequency, and panel may be simultaneously changed. As an example of the corresponding UE capability, the UE may select and report either ‘simultaneous’ or ‘sequential’ to the base station. When the UE reports the UE capability with ‘simultaneous’, it means that the UE may simultaneously change the uplink beam, transmission power, and frequency. It means that the UE supporting multiple panels may change simultaneously panels. When the UE reports the UE capability with ‘sequential’, it means that the UE may sequentially change the uplink beam, transmission power, and frequency. It further means that the UE supporting multiple panels may sequentially change panels.
The UE may report UE capability ‘beamCorrespondenceWithoutUL-BeamSweeping’ for notifying whether a beam correspondence request is satisfied to the base station in addition to reporting a UE capability for supporting the uplink beam, transmission power, frequency, and panel change. The beam correspondence means a capability on whether the UE may select a beam for uplink transmission based on downlink measurement without depending on uplink beam sweeping. When the UE reports that ‘beamCorrespondenceWithoutUL-BeamSweeping’, which is a UE capability for the beam correspondece, may be supported, the UE may select an uplink beam for uplink transmission without uplink beam sweeping and transmit an uplink signal using the uplink beam.
The base station may determine an offset for securing a request time for applying uplink transmission change information through a UE capability reported by the UE. The base station may determine the offset in consideration of one of the following options or a combination thereof:
Option 1) The base station may determine an offset based on a largest value for at least one of a UE capability for uplink beam change reported by the UE, a UE capability for transmission power change, or a UE capability for frequency change.
Option 2) The base station determines an offset based on the largest value among UE capabilities for changes necessary for performing actual uplink transmission among UE capabilities reported by the UE. For example, in the case that the base station indicates an uplink signal to the UE so that only the uplink beam and transmission power change is performed, the base station may determine an offset based on a largest value among a UE capability for uplink beam change and a UE capability for transmission power change. The base station may determine an offset in the same method as that in the above example for an uplink transmission change information combination other than the above example.
Option 3) The base station may determine an offset based on the sum of a UE capability for uplink beam change reported from the UE, a UE capability for transmission power change, and a UE capability for frequency change.
Option 4) The base station may determine an offset based on the sum of UE capabilities for changes necessary for performing actual uplink transmission among UE capabilities reported by the UE. For example, in the case that the base station indicates an uplink signal to the UE so that only the uplink beam and transmission power change is performed, the base station may determine an offset based on the sum of a UE capability for uplink beam change and a UE capability for transmission power change. The base station may determine an offset in the same method as that in the above example for an uplink transmission change information combination other than the above example.
Option 5) When determining an offset through one of the above options 1 to 4, the base station may determine an offset in consideration of a configuration of each uplink transmission signal. For example, in the case that the base station determines the offset for repeatedly transmitting a PUCCH to a plurality of TRPs as the option 1, the UE may determine the offset based on the UE capabilities reported in consideration of the PUCCH configuration. Alternatively, in the case that the UE does not report a UE capability by distinguishing for each uplink signal, the base station may estimate an additional request time due to a PUCCH configuration to the UE capabilities reported by the UE to determine an offset. This may be applied even when the base station determines an offset for transmitting another uplink signal (e.g., PUSCH or SRS).
Option 6) When determining an offset through one of the above options 1 to 4, the base station may determine an offset without distinguishing configurations of each uplink transmission signal.
Option 7) The base station may determine a random value as an offset. In this case, a higher layer parameter configuration of the uplink signal, an uplink resource configuration, and the like may be considered.
Option 8) When the UE supports multiple panels, when determining the offset through options 1 to 6, the base station may determine an offset in additional consideration of an UE capability for panel change.
Each option is an example of the case that the UE reports all of UE capabilities for the above three uplink transmission change information, and when the UE reports only some of the UE capabilities, the base station may apply only the reported UE capabilities to each option to determine the offset.
When the UE reports that the uplink beam, transmission power, and frequency may be changed simultaneously, the base station may select option 1 or option 2 to determine the offset. When the UE reports that the uplink beam, transmission power, and frequency may be sequentially changed, the base station may select option 3 or option 4 to determine the offset. When the UE supports multiple panels and reports that an uplink beam, transmission power, frequency, and panel (or at least two thereof) may be changed simultaneously, the base station may determine the offset in additional consideration of a UE capability for panel change to option 1 according to option 8 or may determine the offset in additional consideration of a UE capability for panel change in option 2 according to option 8. This is an example of the above embodiment, and the base station may determine the offset in consideration of one or a combination of the above-described options 1 to 8 according to the UE capability reported by the UE.
The base station may adjust an offset value determined by the above option according to whether beam correspondent reported by the UE through the UE capability is supported. For example, when the UE supports beam correspondence, the base station may determine an offset value determined through the above option as a final offset value or adjust an offset value to a value smaller than a final offset value. When the UE does not support beam correspondence, the base station may add an additional request time to the offset value determined through the above option.
The base station may adjust an offset value determined by the above-described option according to whether the UE reports an uplink beam to transmit to an uplink for multiple TRPs. When the uplink beam is reported to the base station, this may mean that the corresponding uplink beam is a ‘known’ beam for the UE. When the uplink beam is not reported to the base station, it may mean that the corresponding uplink beam is an ‘unknown’ beam for the UE. When the UE reports an uplink beam to transmit to the uplink to the base station, the base station may determine an offset value determined through the option as a final offset value or adjust an offset value to a value smaller than a final offset value. When the UE does not report the uplink beam to transmit to the uplink to the base station, the base station may add an additional request time to the offset value determined through the option.
The base station may notify the UE of the determined offset. In this case, the base station may explicitly or implicitly notify the UE of the offset:
In the case that the base station explicitly configures the determined offset to the UE: The base station may configure the offset as a new higher layer parameter and explicitly notify the UE of this. For example, the base station may add a new higher layer parameter ‘timeDurationForULSwitch’ to configuration information for PUCCH transmission such as PUCCH-FormatConfig or PUCCH-Config. Similarly for a PUSCH or SRS, the base station may add a new parameter for offset to higher layer parameters for PUSCH transmission and higher layer parameters for SRS transmission. The above example is one of methods of configuring a new higher layer parameter for indicating the offset determined by the base station to the UE, and may be defined as a different name of higher layer parameter having the same function.
In the case that the base station implicitly indicates the determined offset: The base station may implicitly indicate the offset through a configuration(s) for transmitting another uplink signal rather than directly configuring the offset as a higher layer parameter as in the above operation. For example, the base station may indicate the offset through a ‘startingSymbolIndex’ configured in a PUCCH-format[a] (where a is, for example, 0, 1, 2, 3 or 4) in a higher layer parameter PUCCH-Resource. More specifically, as one example of reinforcement methods for indicating PUCCH repetition transmission in a slot, a startingSymbolIndex in PUCCH-format[a] of PUCCH-Resource may be configured as many times as the number of repetitions of PUCCH in a slot. As a detailed example, when the number of repetitions in a slot is, for example, 2, a startingSymbolIndex indicates a transmission start symbol of a first PUCCH repetition transmission occasion in the slot, and a ‘startingSymbolIndex2’ that may be newly added may indicate a transmission start symbol of a second PUCCH repetition transmission occasion in the slot. In this case, a symbol position indicated by a startingSymbolIndex should be faster than that indicated by a startingSymbolIndex2, and the base station may configure an interval between two symbols to be greater than one PUCCH transmission symbol nrofSymbols and an offset determined by the base station. The above example is one example, and the base station may implicitly notify the UE of the offset through a PUCCH resource configuration for PUCCH transmission. Alternatively, when the base station schedules a PUCCH including HACK information of a PDSCH to the UE, the base station may indicate a PDSCH-to-HARQ_feedback timing indicator to the UE so that the time offset is greater than the determined offset. For uplink signals (e.g., PUSCH or SRS) other than PUCCH, the base station may implicitly notify the UE of the offset through a higher layer parameter configuration of an uplink signal or transmission timing indicated by DCI.
When the UE receives an instruction to repeatedly transmit an uplink signal from the base station, the UE may determine an operation for uplink repetition transmission according to whether an offset determined by the base station is explicitly configured or implicitly indicated. When the UE is explicitly configured with an offset from the base station, the UE may configure an interval between repetition transmissions according to the offset in a time domain to transmit an uplink signal. When the UE is implicitly indicated with the offset, the UE transmits an uplink signal according to the higher layer parameter configuration for the uplink signal configured by the base station. When the UE is explicitly configured or implicitly indicated with the offset and applies this to repetition transmission of an uplink signal, the UE may change and transmit at least one of an uplink beam, transmission power, or frequency during the offset according to the capability thereof. When the offset determined by the base station is configured to be larger than the UE capability for changing the uplink beam, transmission power, or frequency, in order to change and transmit the TRP between repetition transmissions, the UE may change the uplink beam or transmission power or perform a frequency change for frequency hopping. When the offset determined by the base station is configured to be smaller than the UE capability for changing the uplink beam, transmission power, or frequency, in order to repeatedly transmit the uplink signal, the base station and the UE may define in advance a default uplink transmission method in consideration of one of the following operations or a combination thereof:
Transmit an uplink signal with the same uplink beam, transmission power, and frequency as previous repetition transmissions: Because the offset determined by the base station is smaller than the UE capability, the UE may satisfy a time for changing a beam, transmission power, or frequency between repetition transmissions. Therefore, the UE may perform next repetition transmission with the beam, transmission power, and frequency applied to previous repetition transmission. Here, the previous repetition transmission means a repetition transmission occasion immediately preceding a repetition transmission occasion to be transmitted. Further, it is possible to use at least one of the uplink beam, transmission power, or frequency in the same manner as in previous (repetition) transmission and to change the rest. For example, it is possible to use the uplink beam and frequency in the same manner as in the previous (repetition) transmission and to change transmission power in the next repetition transmission.
Transmit an uplink signal with an uplink beam, transmission power, and frequency configured to the default: The UE may not satisfy a time for changing a beam, transmission power, or frequency between repetition transmissions because the offset determined by the base station is smaller than the UE capability. Accordingly, the UE may perform the next repetition transmission with a predefined default uplink beam, default transmission power, and default frequency. Here, the base station and the UE may define default transmission information for each uplink signal (PUCCH, PUSCH, or SRS). Alternatively, the base station and the UE may commonly define default transmission information for an uplink signal. Further, it is possible to use at least one of the uplink beam, transmission power, or frequency as a default configuration and to change the rest. For example, it is possible to use the uplink beam and frequency as a default configuration and to change transmission power in the next repetition transmission.
Transmit an uplink signal by conditionally changing an uplink beam, transmission power, or frequency: In the case that mapping between uplink repetition transmission and TRP is configured to ‘sequential’, in a repetition transmission occasion that satisfies the UE capability, an uplink beam, transmission power, or frequency may be changed and transmitted. The UE may transmit an uplink signal with the same configuration as that of the previous repetition transmission occasion in a repetition transmission occasion that does not satisfy the UE capability. For example, when mapping was configured as {TRP1, TRP1, TRP2, TRP2}, first two repetition transmission occasions are transmitted with an uplink beam, transmission power, and frequency for the TRP1. A third repetition transmission occasion should be changed and transmitted to an uplink beam, transmission power, and frequency for the TRP2, but because the offset is smaller than the UE capability, the UE transmits an uplink signal with a configuration for the TRP1 without changing uplink transmission information. The UE may transmit a fourth repetition transmission occasion by changing to an uplink beam, transmission power, and frequency for the TRP2.
Transmit an uplink repetition signal by applying a changeable configuration among an uplink beam, transmission power, or frequency: When the UE compares magnitudes between the offset configured by the base station and the UE capability, the UE may apply some of the UE capabilities some changeable configurations having the UE capability smaller than the offset among UE capabilities to the next repetition transmission occasion. For example, when the offset is larger than the UE capability for uplink beam change and is smaller than the UE capability for other transmission power changes or frequency changes, the UE may change only the uplink beam and apply the same transmission power and frequency as in the previous repetition transmission occasion to transmit the next repetition transmission occasion. When the UE sequentially changes the uplink beam, transmission power, and frequency, the UE compares the offset determined by the base station with the sum of the UE capability combination for changing the uplink beam, transmission power, or frequency. In this case, when a value of the plurality of combinations is smaller than the offset, it is determined according to the priority of the uplink beam, transmission power, or frequency change previously determined between the base station and the UE. For example, when the offset determined by the base station is smaller than the sum of all UE capabilities, and the sum of UE capabilities for uplink beam and transmission power changes, the sum of UE capabilities for uplink beam and frequency changes, and the sum of the capabilities for transmission power and frequency changes are smaller than the offset, and the base station and the UE have previously defined the order of a priority, for example, as {uplink beam>transmission power>frequency}, the UE may change the uplink beam and transmission power to transmit the uplink signal.
Transmit an uplink signal by dropping some symbols or repetition transmission occasions: In order to repeatedly transmit an uplink signal by applying uplink transmission change information, the UE may drop some symbols before a repetition transmission occasion that changes at least one of a beam, transmission power, or frequency and transmit the uplink signal through the remaining resources. For example, when mapping between PUCCH repetition transmission and TRP is configured as {TRP1, TRP1, TRP2, TRP2}, until a required time for changing an uplink beam, transmission power, and frequency for the TRP2 is satisfied at third repetition transmission, the UE does not transmit a PUCCH during the previous symbol. After a required time for changing an uplink beam, transmission power, and frequency is satisfied, the UE may repeatedly transmit a third PUCCH for the remaining symbols.
As another example, when the UE does not satisfy a required time for changing an uplink beam, transmission power, or frequency for repetition transmission in which the TRP is changed, the UE may drop the corresponding uplink repetition transmission occasion. For example, when mapping between PUCCH repetition transmission and TRP is configured as {TRP1, TRP1, TRP2, TRP2}, a third PUCCH repetition transmission occasion may be dropped. Thereafter, a fourth PUCCH repetition transmission occasion may be changed and transmitted to an uplink beam, transmission power, and frequency for the TRP2. As another example, when mapping between PUCCH repetition transmission and TRP is configured as {TRP1, TRP2, TRP1, TRP2}, the second and fourth PUCCH repetition transmission occasions may be dropped to support single TRP-based PUCCH repetition transmission.
In the case that PUCCH repetition transmission is performed in consideration of a channel state for each TRP through the method provided in the above-described embodiments of the disclosure, an increase in coverage of an uplink control signal may be expected. Further, because transmission power is controlled for each transmission and reception point, efficient battery management of the UE may be expected.
This may be equally applied to the magnitude relationship between the time offset for uplink signal transmission and the UE capability. When the time offset is larger than an UE capability for changing the uplink beam, transmission power, or frequency, the UE may transmit the uplink signal. When the time offset is smaller than an UE capability for changing an uplink beam, transmission power, or frequency, similar to the case that the above offset between repetition transmissions does not satisfy the UE capability, the UE may consider one or a combination of the following operations and transmit uplink signals.
Operations according to the above conditions have been described for a method in which the UE supporting a single panel changes an uplink beam, transmission power, or frequency. When the UE may support multiple panels, the UE identifies whether the offset determined by the base station is configured to be smaller than an UE capability for changing the uplink beam, transmission power, frequency, or panel. When the offset determined by the base station is greater than an UE capability for changing the uplink beam, transmission power, frequency, or panel, the UE may transmit the uplink signal. When the offset is configured to be smaller than an UE capability for changing the uplink beam, transmission power, frequency, or panel, the UE may transmit an uplink signal according to one or a combination of the following operations in additional consideration of the UE capability for panel change similar to the case that the offset between repetition transmissions does not satisfy an UE capability.
Here, the previous uplink signal means the most recently transmitted physical channel identical to that of an uplink signal (PUCCH, PUSCH, or SRS) intending to transmit. The base station and the UE may define default transmission information for each uplink signal (PUCCH, PUSCH, or SRS). Alternatively, the base station and the UE may commonly define default transmission information for an uplink signal.
As an embodiment of the disclosure, in the case that the UE performs PUSCH repetition transmission for multiple TRPs according to the above-described Embodiment 1 or 2, a method of generating PH information (may be referred to as PH, PHR, PH value, or PHR information and referred to terms having the same meaning without being limited thereto.) will be described. When reporting PH information on a specific cell, the UE may select and report one of two types of PH information. A first type is actual PHR and is PH information calculated based on actually transmitted PUSCH transmission power. A second type is virtual PHR (or reference format) and does not have an actually transmitting PUSCH, but is PH information calculated based on a transmission power parameter configured to a higher-layer signal. After the PHR is triggered, when a first PUSCH capable of transmitting the corresponding PHR information is a scheduled PUSCH resource, the UE may determine whether PHR calculated for a specific cell is actual PHR or virtual PHR based on an L1 signal and higher-layer signal information received up to a PDCCH monitoring occasion that schedules the corresponding PUSCH. Alternatively, in the case that the PHR is triggered, when a first PUSCH capable of transmitting the PHR information is a configured PUSCH resource, the UE may determine whether PHR calculated for a specific cell is actual PHR or virtual PHR based on higher-layer signal information and the L1 signal received before Tproc,2 based on a first symbol of the corresponding PUSCH. Here, a value calculated based on d2,1=1 and d2,2=0 in Equation 3 may be applied to Tproc,2, but this is only an example, and other values are also sufficiently applicable. For example, when the UE calculates the PHR based on the actual PUSCH (or transmission power or actual transmission for transmitting an actual PUSCH), the UE may express the PHR information as in Equation 10 at a serving cell c, carrier f, BWP b, and PUSCH transmission time point i.
As another example, when the UE calculates PH information based on a virtual PUSCH (or power or reference format calculated based on higher-layer signal information without actual PUSCH transmission), the UE may express PH information as in Equation 11 at a serving cell c, carrier f, BWP b, and PUSCH transmission time point i.
PH
type1,b,f,c(i,j,qd,l)={tilde over (P)}CMAX,f,c(i)−{P0
In the above equation, {tilde over (P)}CMAX,f,c(i) assumes that MPR=MPR=0 dB, A-MPR=0 dB, and P-MPR=0 dB. Here, definitions of MPR, A-MPR, and P-MPR may follow those described in 3GPP TS 38.101-1, TS38.101-2, and TS 38.101-3. Equation 10 to Equation 11 are a first type of PH information. In a communication system to which the disclosure may be applied, first type PH information may indicate PH information on PUSCH transmission power, and second type PH information may indicate PH information on PUCCH transmission power, third type PH information may indicate PH information on SRS transmission power. The disclosure is not limited thereto.
Specifically,
P: P composed of 1 bit is configured to 0 in the case that mpe-Reporting-FR2 is configured and that a P-MPR applied according to TS38.133 is smaller than P-MPR_00 when a serving cell operates in FR2, otherwise P composed of 1 bit is configured to 1. In the case that mpe-Reporting-FR2 is not configured or that the serving cell operates in FR1, P notifies whether power backoff is applied for transmission power control. In the case that the Pcmax,c field has different values according to power backoff being applied to a different value, P is configured to 1.
Pcmax,c: This field is the maximum transmission power value calculated when reporting PH information. The Pcmax,c may have 6 bits of information and select one of total 64 levels of information.
MPE: In the case that mpe-Reporting-FR2 is configured and that the serving cell operates in FR2 and that the P field is configured to 1, the MPE indicates a power backoff value applied to satisfy the MPE requirement. The MPE is a field composed of 2 bits and indicates one value among total 4 steps. In the case that mpe-Reporting-FR2 is not configured, in the case that the serving cell operates in FR1, or in the case that the P field is configured to 0, the MPE may exist as a reversed bit as in R.
R: As a reserved bit, R is configured to 0.
PH: This field indicates a PHR level. The PH may be composed of 6 bits and select one value among total 64 PHR levels.
Specifically,
V: This field is information indicating whether PH information has been calculated based on actual transmission (actual PUSCH) or a reference format (virtual PUSCH). For first type PH information, V is configured to 0 in the case that the PUSCH is actually transmitted, and is configured to 1 in the case that the reference format for the PUSCH is used. For second type PH information, V is configured to 0 in the case that a PUCCH is actually transmitted, and is configured to 1 in the case that a reference format for a PUCCH is used. For third type PH information, V is configured to 0 in the case that an SRS is actually transmitted and is configured to 1 in the case that a reference format for the SRS is used. Further, for first type, second type, and third type PH information, in the case that a value of V is 0, there are Pcmax,f,c and MPE fields thereof, and in the case that a value of V is 1, Pcmax,f,c and MPE fields thereof may be omitted.
As illustrated in
In Equation 8, as described above, when determining PUSCH transmission power, the UE receives configuration information for each different parameter as a higher-layer signal or an L1 signal, and in the case of multiple TRPs, the UE may determine transmission power based on different signal information for each TRP or may receive a configuration of common signal information, but may determine transmission power based on different indexes or indication information within corresponding signal information.
In the case that the UE transmits and receives control and data information to and from multiple TRPs in one serving cell, the UE may transmit PH information to each of the first TRP and the second TRP. Specifically, the UE may transmit a PUSCH including PH information to the first TRP or the second TRP, and the PUSCH may be scheduled in the same TRP as or different TRP from the TRP transmitting the PUSCH or may be preconfigured as a higher-layer signal. In the case that the base station receives the PH information of
As described above, a resource index and an RS resource index, which are values indicated by the SRI field in the DCI described in Embodiment 1 or the CORESETPoolIndex, may be used as information (TRP information) used for distinguishing TRPs. It is noted that the disclosure is not limited thereto, and TRPs may be distinguished according to various types of information.
Embodiment 3-1 proposes a method of using the existing MAC CE format of
In Embodiment 3-1, the UE may not provide a MAC CE format including PH information on at least two TRPs for multiple TRPs within one serving cell. Therefore, in Embodiment 3-2, as illustrated in
In Embodiment 3-3, a bitmap for calculating actual PHR and a bitmap for calculating virtual PHR are fixed without necessity to utilize the reserved bits of
As illustrated in
Embodiments 3-1 to 3-4 relate to a method of generating PH information in the case that the UE is configured with one serving cell in a multi-TRP situation. In the following embodiments, a method of generating PH information in the case that the UE is configured with a plurality of serving cells in a multi-TRP situation will be described.
Similar to
The UE may report a PHR MAC CE having the MAC CE format illustrated in
In the above Embodiments 3-1 to 3-7, there will be no problem the case that the corresponding PUSCH transmission and reception are executed in only one TRP for a method based on a TRP in which a PUSCH including specific PH information is transmitted and received during an operation of determining based on which TRP was determined specific PH information. However, in the case that the corresponding PUSCH is repeatedly transmitted in consideration of multiple TRPs (e.g., PUSCH repetition transmissions are performed for each of the first TRP and the second TRP), the above methods may not be applied. In this case, both the UE and the base station may determine based on a TRP in which a first PUSCH is transmitted and received or a TRP in which a last PUSCH is transmitted and received.
Further, in the above-described embodiments, the MAC entity may determine based on which TRP PH information was determined based on a TRP in which a PUSCH including PH information was transmitted and received. Specifically, in an operation of determining based on which TRP PH information is generated (or calculated), the MAC entity may consider a TRP in which a PUSCH including the corresponding PH information is transmitted and received. For example, the MAC entity may determine that PH information included in a PUSCH transmitted and received through a first TRP is calculated based on the first TRP. Alternatively, the MAC entity may determine that PH information included in a PUSCH transmitted and received through a second TRP is calculated based on the second TRP. Here, the MAC entity may mean a MAC entity of the base station or a MAC entity of the UE.
In a situation in which the UE operates a plurality of cells for PUSCH transmission, PH information on other cells is included in PUSCH transmission resources transmitting in a specific cell A, and in this case, in the case that there are a plurality of PUSCHs scheduled in other cells, it may be necessary to determine based on which PUSCH transmission resource PH information is reported.
As an example, in a situation in which the UE is configured with a plurality of cells for PUSCH transmission and in which a subcarrier value μ1 of an uplink BWP b1 2700 of a carrier f1 of a serving cell c1 is smaller than a subcarrier value 2 of an uplink BWP b2 2702 of a carrier f2 of a serving cell c2, when the UE provides type 1 PHR included in one PUSCH transmission 2708 in one slot 2704 in the active uplink BWP b1 2700 overlapped with a plurality of slots 2705 and 2706 in the active uplink BWP b2 2702, the UE provides type 1 PHR for a first PUSCH 2710 in the first slot 2705 of the plurality of slots 2705 and 2706 of the active UL BWP b2 2702 completely overlapped with the slot 2704 of the active uplink BWP b1 2700.
As another example, in a situation in which the UE is configured with a plurality of cells for PUSCH transmission and in which a subcarrier value μ1 of the uplink BWP b1 2700 of the carrier f1 of the serving cell c1 is the same as a subcarrier value μ2 of the uplink BWP b2 2702 of the carrier f2 of the serving cell c2, when the UE provides type 1 PHR included in one PUSCH 2708 transmission in one slot 2704 in the active uplink BWP b1 2700, the UE provides type 1 PHR for the first PUSCH 2710 in the slot of the active UL BWP b2 2702 overlapped with the slot 2704 of the active uplink BWP b1 2700.
As another example, when the UE is configured with a plurality of cells for PUSCH transmission and transmits type 1 PHR in PUSCH transmission, which is a PUSCH repetition transmission type B with normative repetition transmission over a plurality of slots in the active uplink BWP b1 2700 and overlapped with one or a plurality of slots of the active uplink BWP b2 2702, the UE transmits type 1 PHR for a first PUSCH in a first slot of one or a plurality of slots of the active uplink b2 overlapped with the plurality of slots of normative repetition transmission of the active uplink BWP b1.
When describing with reference to
As another example, as described with reference to
Alternatively, in the case that the PUSCH does not exist, the UE calculates virtual PH information calculated based on a specific CORESETPoolIndex indicated by a higher-layer signal or an L1 signal in advance. Alternatively, in the case that the PUSCH does not exist, the UE always calculates virtual PH information calculated based on a value of CORESETPoolIndex 0.
Although
All of the above-described methods assume that the UE calculates PH information based on Equation 10 or Equation 11, and have been described. However, in a situation in which the UE of the disclosure operates communication with a plurality of TRPs, a method of calculating modified PH information and reporting it to the base station may be possible. For example, in the case that the UE is configured with 5 serving cells and transmits and receives to and from total 2 TRPs, the UE should arithmetically calculate each of maximum 10 PH information, and include and transmit them in the MAC CE according to an MAC CE PHR format. Therefore, there is a possibility that the magnitude of the MAC CE format increases as the number of serving cells or the number of TRPs increases. Accordingly, it requires a larger data magnitude; thus, the base station requires more radio resources. Therefore, Embodiment 5 provides a method for the base station to receive MAC CE PHR information from the UE while efficiently using radio resources.
Therefore, a method of constituting one PH information regardless of the number of TRPs for each serving cell may be possible in the form of Equation 12.
PH
type1,b,f,c(i,j,qd,l)=PHtype1,b,f,c,t1(i,j,qd,l)▪PHtype1,b,f,c,t2(i,j,qd,l) Equation 12
PHtype1,b,f,c,t1(i,j,qd,l) e.is the same as Equation 10 or Equation 11, and t1 means PH information on a TRP 1 (or connected to a CORESETPoolIndex 0). PHtype1,b,f,c,t2(i,j,qd,l) is the same as Equation 10 or Equation 11, and t2 means PH information on a TRP 2 (or connected to a CORESETPoolIndex 0). In Equation 12, a value of PHtype1,b,f,c(i,j,qd,l) is a result value in which PHtype1,b,f,c,t1(i,j,qd,l) and PHtype1,b,f,c,t2(i,j,qd,l) are obtained through a specific function (▪). In the disclosure, a specific function is not limited, and for example, ▪ is four arithmetic operations such as addition, subtraction, division, and multiplication or may be the maximum value (A▪B=maximum(A,B)), the minimum value (A▪B=minimum(A,B)), or an average value(A▪B=Average(A,B)). Further, other arithmetic operations defined by the above combinations may be sufficiently possible, and PHtype1,b,f,c(i,j,qd,l) may be calculated based on a specific function according to various forms without being limited thereto.
In the case that, in one serving cell, the UE performs simultaneous PUSCH transmission for a plurality of TRPs, the UE may calculate PH information based on Equation 13.
Equation 13 may mean that the UE includes the remaining transmission power value (power headroom) information except for PUSCH transmission power simultaneously transmitted for each TRP at the maximum transmission power. Further, PCMAX,f,c(i) determined by the UE in Equation 13 may be determined by assuming a value of at least one or part of MPR, A-MPR, or P-MPR to a different value unlike Equation 10 or Equation 11. PH′type1,b,f,c,t(i,j,qd,l) in Equation 13 may correspond to at least one of the same actual transmission power as that in Equation 14 or the same virtual transmission power as that in Equation 15 for a specific TRP t.
According to the above-described Equation 12 to Equation 15, the UE may be sufficiently applied to at least one of embodiments described in this disclosure or a combination thereof.
In the case that the UE is configured with a plurality of serving cells according to the method provided in Embodiment 5, the UE may provide PHR to the base station by utilizing the same MAC CE format as that in
With reference to
In step 2820, the UE may receive a downlink signal (e.g., CSI-RS, SSB, and the like) from a first TRP or a second TRP.
In step 2830, the UE may calculate a downlink path attenuation value based on the measurement result of the downlink signal received in step 2820.
In step 2840, in the case that the PHR is triggered, the UE (MAC entity) may generate a MAC CE having a MAC CE format according to the above-described Embodiment 3 or a MAC CE format according to a combination thereof. In the case that the UE is configured with a plurality of serving cells, the UE may calculate PH information in consideration of at least one of detailed embodiments described in the above-described Embodiment 4 or a combination thereof and include the PH information in the MAC CE. Further, the UE may calculate (generate) PH information in consideration of at least one of detailed embodiments described in the above-described Embodiment 5 or a combination thereof. In the disclosure, in the case that a timer configured according to a timer value included in PHR related configuration information has expired or in the case that a change in a downlink path attenuation value is a specific threshold value or more, the PHR may be triggered.
In step 2850, the UE may transmit a PUSCH including an MAC CE generated in step 2840 to any one TRP of at least one TRP.
Steps 2810 to 2850 of
With reference to
In step 2920, the base station may transmit a downlink signal (e.g., CSI-RS, SSB, and the like) to the UE through at least one TRP.
In step 2930, in the case that the PHR is triggered, the base station may receive an MAC CE including PH information through any one TRP among at least one TRP. In the disclosure, in the case that a timer configured according to a timer value included in PHR related configuration information has expired or in the case that a change in a downlink path attenuation value is a specific threshold value or more, the PHR may be triggered. In step 2930, it may be determined that PH information received by the base station from the UE considers the assumption determined based on at least one of detailed embodiments described in the above-described Embodiment 4 or 5 or a combination thereof.
In step 2940, the base station may optimize a system operation based on the PH information received in step 2930. For example, in the case that PH information reported by a specific UE is a remaining amount of power having a positive value, the base station may increase system yield by allocating more resources to the corresponding UE, whereas in the case that the PH information is a remaining amount of power having a negative value, by re-instructing scheduling appropriate for the maximum transmission power and allocating the remaining resources to other UEs because transmission power of the corresponding UE has already exceeded the maximum value, the base station may optimize system yield.
Steps 2910 to 2940 of
With reference to
The transceivers 3000 and 3010 may transmit and receive signals to and from the base station. Here, the signal may include control information and data. To this end, the transceiver may include an RF transmitter for up-converting and amplifying a frequency of a signal to be transmitted, and an RF receiver for low-noise amplifying a received signal and down-converting a frequency thereof. However, this is only an embodiment of the transceivers 3000 and 3010, and components of the transceivers 3000 and 3010 are not limited to the RF transmitter and the RF receiver.
Further, the transceivers 3000 and 3010 may receive signals through a wireless channel, output the signals to the processor 3005, and transmit signals output from the processor 3005 through a wireless channel.
The memory may store programs and data necessary for an operation of the UE. Further, the memory may store control information or data included in signals transmitted and received by the UE. The memory may include a storage medium such as a read only memory (ROM), a random access memory (RAM), a hard disk, a compact disc read-only memory (CD-ROM), and a digital versatile disc (DVD), or a combination of storage media. Further, there may be a plurality of memories.
Further, the processor 3005 may control a series of processes so that the UE may operate according to the above-described embodiment. For example, the processor 3005 may control components of the UE to simultaneously receive a plurality of PDSCHs by receiving DCI composed of two layers. There may be a plurality of processors 3005, and the processor 3005 may execute a program stored in a memory to perform a component control operation of the UE.
With reference to
The transceivers 3100 and 3110 may transmit and receive signals to and from the UE. Here, the signal may include control information and data. To this end, the transceivers 3100 and 3110 may include an RF transmitter for up-converting and amplifying a frequency of a signal to be transmitted, and an RF receiver for low-noise amplifying a received signal and down-converting a frequency thereof. However, this is only an embodiment of the transceivers 3100 and 3110, and components of the transceivers 3100 and 3110 are not limited to the RF transmitter and the RF receiver.
Further, the transceivers 3100 and 3110 may receive signals through a wireless channel, output the signals to the processor 3105, and transmit signals output from the processor 3105 through a wireless channel.
The memory may store programs and data necessary for an operation of the base station. Further, the memory may store control information or data included in signals transmitted and received by the base station. The memory may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. Further, there may be a plurality of memories.
The processor 3105 may control a series of processes so that the base station operates according to the above-described embodiment of the disclosure. For example, in order to constitute and transmit two layers of DCI including allocation information on a plurality of PDSCHs, the processor 3105 may control each component of the base station. There may be a plurality of processors 3105, and by executing a program stored in the memory, the processor 3105 may perform a component control operation of the base station.
Methods according to the embodiments described in the claims or specifications of the disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.
In the case of being implemented in software, a computer readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions for causing an electronic device to execute methods according to embodiments described in claims or specification of the disclosure.
Such programs (software modules, software) may be stored in a random access memory, a non-volatile memory including a flash memory, a read only memory (ROM), an electrically erasable programmable ROM (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), digital versatile discs (DVDs), another form of optical storage device, or a magnetic cassette. Alternatively, the programs may be stored in a memory composed of a combination of some or all thereof. Further, each constitution memory may be included in the plural.
Further, the program may be stored in an attachable storage device that may access through a communication network such as the Internet, Intranet, local area network (LAN), wide LAN (WLAN), or storage area Network (SAN), or a communication network composed of a combination thereof. Such a storage device may access a device implementing an embodiment of the disclosure through an external port. Further, a separate storage device on the communication network may access the device implementing the embodiment of the disclosure.
In the above-described specific embodiments of the disclosure, components included in the disclosure have been expressed in the singular or the plural according to the presented specific embodiments. However, the singular or plural expression is appropriately selected for a presented situation for convenience of description, and the disclosure is not limited to the singular or plural components, and even if a component is represented in the plural, it may be composed of the singular, or even if a component is represented in the singular, it may be composed of the plural.
Embodiments of the disclosure disclosed in this specification and drawings merely present specific examples in order to easily describe the technical contents of the disclosure and help the understanding of the disclosure, and they are not intended to limit the scope of the disclosure. That is, it will be apparent to those of ordinary skill in the art to which the disclosure pertains that other modifications based on the technical spirit of the disclosure may be implemented. Further, each of the above embodiments may be operated in combination with each other, as needed. For example, a base station and a UE may be operated by combining parts of an embodiment of the disclosure and another embodiment. For example, a base station and a UE may be operated by combining parts of Embodiment 1 and Embodiment 2 of the disclosure. As another example, the UE of the disclosure may be operated by combining parts of Embodiments 3 to 5. In the case that a plurality of serving cells are configured to the UE, the UE may generate a MAC CE including PH information according to at least one of detailed embodiments described in Embodiment 3 or a combination thereof, and in this case, the UE may calculate PH information according to at least one or a combination of detailed embodiments described in Embodiment 4. As another example, the base station and the UE may be operated by combining parts of Embodiments 1 to 5 of the disclosure. For example, as described in Embodiment 1, the UE may classify a TRP according to a value indicated by an SRI field in DCI, that is, an RS resource index or a resource index, and calculate (generate) PH information and transmit a PHR MAC CE. In the case that a plurality of serving cells or one serving cell is configured in the UE, the UE may generate the PH information according to at least one of detailed embodiments described in Embodiment 5 or a combination thereof.
Although the above embodiments have been presented based on an FDD LTE system, other modifications based on the technical idea of the above embodiment may be implemented even in other systems such as a TDD LTE system, 5G or NR system.
In the drawings for describing the method of the disclosure, the order of description does not necessarily correspond to the order of execution, and the precedence relationship may be changed or may be executed in parallel.
Alternatively, the drawings illustrating the method of the disclosure may omit some components and include only some components within the scope that does not impair the essence of the disclosure.
Further, the method of the disclosure may be implemented in a combination of some or all of the contents included in each embodiment within a range that does not impair the essence of the disclosure.
Various embodiments of the disclosure have been described above. The foregoing description of the disclosure is for illustrative purposes, and the embodiments of the disclosure are not limited to the disclosed embodiments. Those of ordinary skill in the art to which the disclosure belongs will be able to understand that it may be easily modified into other specific forms without changing the technical spirit or essential features of the disclosure. The scope of the disclosure is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0043647 | Apr 2021 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/004800 | 4/4/2022 | WO |
