Patent Application
20240251423
This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2023-0001931, filed on Jan. 5, 2023, in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety.
The disclosure relates to operations of a user equipment (UE) and a base station in a wireless communication system. More specifically, the disclosure relates to an antenna switching method in a wireless communication system and an apparatus capable of performing the same.
5th generation (5G) mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in “Sub 6 GHz” bands such as 3.5 GHz, but also in “Above 6 GHz” bands referred to as mmWave including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95 GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G.
In the initial stage of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand, (eMBB), Ultra Reliable & Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for alleviating radio-wave path loss and increasing radio-wave transmission distances in mmWave, numerology (for example, operating multiple subcarrier spacings) for efficiently utilizing mm Wave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large-capacity data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network customized to a specific service.
Currently, there is ongoing discussion regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for securing coverage in an area in which communication with terrestrial networks is impossible, and positioning.
Moreover, there has been ongoing standardization in wireless interface architecture/protocol fields regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture/service fields regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.
If such 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with extended Reality (XR) for efficiently supporting Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR), and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.
Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for securing coverage in terahertz bands of 6G mobile communication technologies, Full Dimensional MIMO (FD-MIMO), multi-antenna transmission technologies such as array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.
The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.
A disclosed embodiment may provide an apparatus and a method capable of effectively providing a service in a mobile communication system.
The disclosure may provide methods and apparatuses of antenna switching in a wireless communication system.
The technical objects to be achieved by various embodiments of the disclosure are not limited to the technical objects mentioned above, and other technical objects not mentioned may be considered by those skilled in the art from various embodiments of the disclosure to be described below.
According to an embodiment, a method performed by a user equipment (UE) in a communication system may be provided.
According to an embodiment, the method may include receiving, via a higher layer signaling, a sounding reference signal (SRS) configuration including SRS resource sets configured with antenna switching.
According to an embodiment, the method may include receiving downlink control information (DCI) for SRS triggering.
According to an embodiment, the method may include transmitting an SRS based on the SRS configuration and the DCI.
According to an embodiment, the SRS resource sets may respectively include slot offsets.
According to an embodiment, a slot offset may be a number of slots between the DCI and an SRS transmission corresponding to SRS resource set including the slot offset.
According to an embodiment, in case that none of the SRS resource sets is configured with a list of available slot offsets, values of the slot offsets may be different from each other.
According to an embodiment, the SRS resource sets may be configured across all configured bandwidth parts (BWPs) in a carrier.
According to an embodiment, 1T4R for the antenna switching may be supported by the UE.
According to an embodiment, the method may include transmitting capability information including an SRS transmission port switching pattern supported by the UE.
According to an embodiment, the SRS transmission port switching pattern may include the 1T4R.
According to an embodiment, an available slot offset may be a number of available slots from a slot n+k to a slot for the SRS transmission corresponding to SRS resource set including the slot offset, wherein n is a slot with the DCI and k is the slot offset.
According to an embodiment, a user equipment (UE) in a communication system may be provided.
According to an embodiment, the UE may include a transceiver; and a processor coupled with the transceiver.
According to an embodiment, the processor may be configured to receive, via a higher layer signaling, a sounding reference signal (SRS) configuration including SRS resource sets configured with antenna switching.
According to an embodiment, the processor may be configured to receive downlink control information (DCI) for SRS triggering.
According to an embodiment, the processor may be configured to transmit an SRS based on the SRS configuration and the DCI.
According to an embodiment, the SRS resource sets may respectively include slot offsets.
According to an embodiment, a slot offset may be a number of slots between the DCI and an SRS transmission corresponding to SRS resource set including the slot offset.
According to an embodiment, in case that none of the SRS resource sets is configured with a list of available slot offsets, values of the slot offsets may be different from each other.
According to an embodiment, the SRS resource sets may be configured across all configured bandwidth parts (BWPs) in a carrier.
According to an embodiment, 1T4R for the antenna switching may be supported by the UE.
According to an embodiment, the method may include transmitting capability information including an SRS transmission port switching pattern supported by the UE.
According to an embodiment, the SRS transmission port switching pattern may include the 1T4R.
According to an embodiment, an available slot offset may be a number of available slots from a slot n+k to a slot for the SRS transmission corresponding to SRS resource set including the slot offset, wherein n is a slot with the DCI and k is the slot offset.
According to an embodiment, a method performed by a base station in a communication system may be provided.
According to an embodiment, the method may include transmitting, to a user equipment (UE) via a higher layer signaling, a sounding reference signal (SRS) configuration including SRS resource sets configured with antenna switching.
According to an embodiment, the method may include transmitting, to the UE, downlink control information (DCI) for SRS triggering.
According to an embodiment, the method may include receiving, from the UE, an SRS associated with the SRS configuration and the DCI.
According to an embodiment, the SRS resource sets may respectively include slot offsets.
According to an embodiment, a slot offset may be a number of slots between the DCI and an SRS transmission corresponding to SRS resource set including the slot offset.
According to an embodiment, in case that none of the SRS resource sets is configured with a list of available slot offsets, values of the slot offsets may be different from each other.
According to an embodiment, the SRS resource sets may be configured across all configured bandwidth parts (BWPs) in a carrier.
According to an embodiment, 1T4R for the antenna switching may be supported by the UE.
According to an embodiment, the method may include receiving capability information including an SRS transmission port switching pattern supported by the UE.
According to an embodiment, the SRS transmission port switching pattern may include the 1T4R.
According to an embodiment, an available slot offset may be a number of available slots from a slot n+k to a slot for the SRS transmission corresponding to SRS resource set including the slot offset, wherein n is a slot with the DCI and k is the slot offset.
According to an embodiment, a base station in a communication system may be provided.
According to an embodiment, the base station may include a transceiver; and a processor coupled with the transceiver.
According to an embodiment, the processor may be configured to transmit, to a user equipment (UE) via a higher layer signaling, a sounding reference signal (SRS) configuration including SRS resource sets configured with antenna switching.
According to an embodiment, the processor may be configured to transmit, to the UE, downlink control information (DCI) for SRS triggering.
According to an embodiment, the processor may be configured to receive, from the UE, an SRS associated with the SRS configuration and the DCI.
According to an embodiment, the SRS resource sets may respectively include slot offsets.
According to an embodiment, a slot offset may be a number of slots between the DCI and an SRS transmission corresponding to SRS resource set including the slot offset.
According to an embodiment, in case that none of the SRS resource sets is configured with a list of available slot offsets, values of the slot offsets may be different from each other.
According to an embodiment, the SRS resource sets may be configured across all configured bandwidth parts (BWPs) in a carrier.
According to an embodiment, 1T4R for the antenna switching may be supported by the UE.
According to an embodiment, the method may include receiving capability information including an SRS transmission port switching pattern supported by the UE.
According to an embodiment, the SRS transmission port switching pattern may include the 1T4R.
According to an embodiment, an available slot offset may be a number of available slots from a slot n+k to a slot for the SRS transmission corresponding to SRS resource set including the slot offset, wherein n is a slot with the DCI and k is the slot offset.
A disclosed embodiment advantageously provides an apparatus and a method capable of effectively providing a service in a mobile communication system.
The disclosure may provide methods and apparatuses of antenna switching in a wireless communication system.
The effects that can be achieved through the disclosure are not limited to the effects mentioned in the various embodiments, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.
Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.
Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.
Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.
In describing the embodiments, descriptions related to technical contents well-known in the art and not associated directly with the disclosure will be omitted. Such an omission of unnecessary descriptions is intended to prevent obscuring of the main idea of the disclosure and more clearly transfer the main idea.
For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Further, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals.
The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following embodiments are provided only to completely disclose the disclosure and inform those skilled in the art of the scope of the disclosure, and the disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or like reference numerals designate the same or like elements. Furthermore, in describing the disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it is determined that the description may make the subject matter of the disclosure unnecessarily unclear. The terms which will be described below are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the users, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.
In the following description, a base station is an entity that allocates resources to terminals, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. In the disclosure, a “downlink (DL)” refers to a radio link via which a base station transmits a signal to a terminal, and an “uplink (UL)” refers to a radio link via which a terminal transmits a signal to a base station. Furthermore, in the following description, LTE or LTE-A systems may be described by way of example, but the embodiments of the disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. Examples of such communication systems may include 5th generation mobile communication technologies (5G, new radio, and NR) developed beyond LTE-A, and in the following description, the “5G” may be the concept that covers the exiting LTE, LTE-A, or other similar services. In addition, based on determinations by those skilled in the art, the embodiments of the disclosure may also be applied to other communication systems through some modifications without significantly departing from the scope of the disclosure.
Herein, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.
Furthermore, each block of the flowchart illustrations may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.
As used in the embodiments of the disclosure, the “unit” refers to a software element or a hardware element, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), which performs a predetermined function. However, the “unit” does not always have a meaning limited to software or hardware. The “unit” may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the “unit” includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The elements and functions provided by the “unit” may be either combined into a smaller number of elements, or a “unit,” or divided into a larger number of elements, or a “unit.” Moreover, the elements and “units” or may be implemented to reproduce one or more CPUs within a device or a security multimedia card. Furthermore, the “unit” in the embodiments may include one or more processors.
A wireless communication system is advancing to a broadband wireless communication system for providing high-speed and high-quality packet data services using communication standards, such as high-speed packet access (HSPA) of 3GPP, LTE {long-term evolution or evolved universal terrestrial radio access (E-UTRA)}, LTE-Advanced (LTE-A), LTE-Pro, high-rate packet data (HRPD) of 3GPP2, ultra-mobile broadband (UMB), IEEE 802.16e, and the like, as well as typical voice-based services.
As a typical example of the broadband wireless communication system, an LTE system employs an orthogonal frequency division multiplexing (OFDM) scheme in a downlink (DL) and employs a single carrier frequency division multiple access (SC-FDMA) scheme in an uplink (UL). The uplink indicates a radio link through which a user equipment (UE) (or a mobile station (MS)) transmits data or control signals to a base station (BS) (eNode B), and the downlink indicates a radio link through which the base station transmits data or control signals to the UE. The above multiple access scheme may separate data or control information of respective users by allocating and operating time-frequency resources for transmitting the data or control information for each user so as to avoid overlapping each other, that is, so as to establish orthogonality.
Since a 5G communication system, which is a post-LTE communication system, must freely reflect various requirements of users, service providers, and the like, services satisfying various requirements must be supported. The services considered in the 5G communication system include enhanced mobile broadband (eMBB) communication, massive machine-type communication (mMTC), ultra-reliability low-latency communication (URLLC), and the like.
eMBB aims at providing a data rate higher than that supported by existing LTE, LTE-A, or LTE-Pro. For example, in the 5G communication system, eMBB must provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink for a single base station. Furthermore, the 5G communication system must provide an increased user-perceived data rate to the UE, as well as the maximum data rate. In order to satisfy such requirements, transmission/reception technologies including a further enhanced multi-input multi-output (MIMO) transmission technique are required to be improved. In addition, the data rate required for the 5G communication system may be obtained using a frequency bandwidth more than 20 MHz in a frequency band of 3 to 6 GHz or 6 GHz or more, instead of transmitting signals using a transmission bandwidth up to 20 MHz in a band of 2 GHz used in LTE.
In addition, mMTC is being considered to support application services such as the Internet of Things (IOT) in the 5G communication system. mMTC has requirements, such as support of connection of a large number of UEs in a cell, enhancement coverage of UEs, improved battery time, a reduction in the cost of a UE, and the like, in order to effectively provide the Internet of Things. Since the Internet of Things provides communication functions while being provided to various sensors and various devices, it must support a large number of UEs (e.g., 1,000,000 UEs/km2) in a cell. In addition, the UEs supporting mMTC may require wider coverage than those of other services provided by the 5G communication system because the UEs are likely to be located in a shadow area, such as a basement of a building, which is not covered by the cell due to the nature of the service. The UE supporting mMTC must be configured to be inexpensive, and may require a very long battery life-time such as 10 to 15 years because it is difficult to frequently replace the battery of the UE.
Lastly, URLLC, which is a cellular-based mission-critical wireless communication service, may be used for remote control for robots or machines, industrial automation, unmanned aerial vehicles, remote health care, emergency alert, and the like. Thus, URLLC must provide communication with ultra-low latency and ultra-high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 ms, and also requires a packet error rate of 10-5 or less. Therefore, for the services supporting URLLC, a 5G system must provide a transmit time interval (TTI) shorter than those of other services, and also may require a design for assigning a large number of resources in a frequency band in order to secure reliability of a communication link.
The three 5G services, that is, eMBB, URLLC, and mMTC, may be multiplexed and transmitted in a single system. In this case, different transmission/reception techniques and transmission/reception parameters may be used between services in order to satisfy different requirements of the respective services. Of course, 5G is not limited to the above-described three services.
Hereinafter, the frame structure of a 5G system will be described in more detail with reference to the accompanying drawings.
In
Next, bandwidth part (BWP) configuration in a 5G communication system will be described in detail with reference to the accompanying drawings.
Obviously, the above example is not limiting, and various parameters related to the bandwidth part may be configured for the UE, in addition to the above configuration information. The above pieces of information may be transferred from the base station to the UE through higher layer signaling, for example, radio resource control (RRC) signaling. One configured bandwidth part or at least one bandwidth part among multiple configured bandwidth parts may be activated. Whether or not to activate a configured bandwidth part may be semi-statically transferred from the base station to the UE through RRC signaling, or dynamically transferred through downlink control information (DCI).
According to some embodiment, the UE, prior to radio resource control (RRC) connection, may have an initial BWP for initial access configured by the base station through a master information block (MIB). To be more specific, the UE may receive configuration information regarding a control resource set (CORESET) and a search space which may be used to transmit a PDCCH for receiving system information (which may correspond to remaining system information (RMSI) or system information block 1 (SIB1) necessary for initial access through the MIB in the initial access step. Each of the control resource set and the search space configured by the MIB may be considered as identity (ID) 0. The base station may notify the UE of configuration information, such as frequency allocation information regarding control resource set #0, time allocation information, and numerology, through the MIB. In addition, the base station may notify the UE of configuration information regarding the monitoring cycle and occasion regarding control resource set #0, that is, configuration information regarding control resource set #0, through the MIB. The UE may consider that a frequency domain configured by control resource set #0 acquired from the MIB is an initial bandwidth part for initial access. The ID of the initial bandwidth part may be considered to be 0.
The bandwidth part-related configuration supported by 5G may be used for various purposes.
According to some embodiments, if the bandwidth supported by the UE is smaller than the system bandwidth, this may be supported through the bandwidth part configuration. For example, the base station may configure the frequency location (configuration information 2) of the bandwidth part for the UE such that the UE can transmit/receive data at a specific frequency location within the system bandwidth.
In addition, according to some embodiments, the base station may configure multiple bandwidth parts for the UE for the purpose of supporting different numerologies. For example, in order to support a UE's data transmission/reception using both a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz, two bandwidth parts may be configured as subcarrier spacings of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be subjected to frequency division multiplexing, and when data is to be transmitted/received at a specific subcarrier spacing, the bandwidth part configured as the corresponding subcarrier spacing may be activated.
In addition, according to some embodiments, the base station may configure bandwidth parts having different sizes of bandwidths for the UE for the purpose of reducing power consumed by the UE. For example, if the UE supports a substantially large bandwidth (for example, 100 MHz) and always transmits/receives data with the corresponding bandwidth, a substantially large amount of power consumption may occur. Particularly, it may be substantially inefficient from the viewpoint of power consumption to unnecessarily monitor the downlink control channel with a large bandwidth of 100 MHz in the absence of traffic. In order to reduce power consumed by the UE, the base station may configure a bandwidth part of a relatively small bandwidth, for example, a bandwidth part of 20 MHz, for the UE. The UE may perform a monitoring operation in the 20 MHz bandwidth part in the absence of traffic, and may transmit/receive data with the 100 MHz bandwidth part as instructed by the base station if data has occurred.
In connection with the bandwidth part configuring method, UEs, before being RRC-connected, may receive configuration information regarding the initial bandwidth part through a master information block (MIB) in the initial access step. To be more specific, a UE may have a control resource set (CORESET) configured for a downlink control channel which may be used to transmit downlink control information (DCI) for scheduling a system information block (SIB) from the MIB of a physical broadcast channel (PBCH). The bandwidth of the control resource set configured by the MIB may be considered as the initial bandwidth part, and the UE may receive, through the configured initial bandwidth part, a physical downlink shared channel (PDSCH) through which an SIB is transmitted. The initial bandwidth part may be used not only for the purpose of receiving the SIB, but also for other system information (OSI), paging, random access, or the like.
If a UE has one or more bandwidth parts configured therefor, the base station may instruct to the UE to change (or switch) the bandwidth parts by using a bandwidth part indicator field inside DCI. As an example, if the currently activated bandwidth part of the UE is bandwidth part #1 301 in
As described above, DCI-based bandwidth part changing may be indicated by DCI for scheduling a PDSCH or a PUSCH, and a UE, upon receiving a bandwidth part change request, needs to be able to receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI in the changed bandwidth part with no problem. To this end, a requirement regarding the delay time (TBWP) required during a bandwidth part change are specified standards, and may be defined, for example, as follows:
Note 1
The requirement regarding the bandwidth part change delay time supports type 1 or type 2, depending on the capability of the UE. The UE may report the supportable bandwidth part delay time type to the base station.
If the UE has received DCI including a bandwidth part change indicator in slot n, according to the above-described requirement regarding the bandwidth part change delay time, the UE may complete a change to the new bandwidth part indicated by the bandwidth part change indicator at a timepoint not later than slot n+TBWP, and may transmit/receive a data channel scheduled by the corresponding DCI in the newly changed bandwidth part. If the base station wants to schedule a data channel by using the new bandwidth part, the base station may determine time domain resource allocation regarding the data channel in view of the UE's bandwidth part change delay time (TBWP). That is, when scheduling a data channel by using the new bandwidth part, the base station may schedule the corresponding data channel after the bandwidth part change delay time, in connection with the method for determining time domain resource allocation regarding the data channel. Accordingly, the UE may not expect that the DCI that indicates a bandwidth part change may indicate a slot offset (KO or K2) value smaller than the bandwidth part change delay time (TBWP).
If the UE has received DCI (for example, DCI format 1_1 or 0_1) indicating a bandwidth part change, the UE may perform no transmission or reception during a time interval from the third symbol of the slot used to receive a PDCCH including the corresponding DCI to the start point of the slot indicated by a slot offset (KO or K2) value indicated by a time domain resource allocation indicator field in the corresponding DCI. For example, if the UE has received DCI indicating a bandwidth part change in slot n, and if the slot offset value indicated by the corresponding DCI is K, the UE may perform no transmission or reception from the third symbol of slot n to the symbol before slot n+K (that is, the last symbol of slot n+K−1).
Next, synchronization signal (SS)/PBCH blocks in 5G will be described.
An SS/PBCH block may refer to a physical layer channel block including a primary SS (PSS), a secondary SS (SSS), and a PBCH. Details thereof are as follows:
The UE may detect the PSS and the SSS in the initial access step, and may decode the PBCH. The UE may acquire an MIB from the PBCH, and this may be used to configure control resource set (CORESET) #0 (which may correspond to a control resource set having a control resource set index of 0). The UE may monitor control resource set #0 by assuming that the demodulation reference signal (DMRS) transmitted in the selected SS/PBCH block and control resource set #0 is quasi-co-located (QCL). The UE may receive system information with downlink control information transmitted in control resource set #0. The UE may acquire configuration information related to a random access channel (RACH) necessary for initial access from the received system information. The UE may transmit a physical RACH (PRACH) to the base station in view of a selected SS/PBCH index, and the base station, upon receiving the PRACH, may acquire information regarding the SS/PBCH block index selected by the UE. The base station may know which block the UE has selected from respective SS/PBCH blocks, and the fact that control resource set #0 associated therewith is monitored.
Discontinuous reception (DRX) refers to an operation in which a UE currently using a service discontinuously receives data in an RRC-connected state in which a radio link is configured between the base station and the UE. If the DRX is applied, the UE may turn on a receiver at a specific timepoint so as to monitor a control channel, and may turn off the receiver if there is no data received for a predetermined period of time, thereby reducing power consumed by the UE. The DRX operation may be controlled by a MAC layer device, based on various parameters and timers.
Referring to
drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, ra-ContentionResolutionTimer, and the like are timers having values configured by the base station, and have functions which cause the UE to monitor the PDCCH in a situation in which a predetermined condition is satisfied.
drx-onDurationTimer 615 is a parameter for configuring the minimum time during which the UE is awake at the DRX cycle. drx-InactivityTimer 620 is a parameter for configuring a time during which the UE is additionally awake upon receiving (630) a PDCCH indicating new uplink transmission or downlink transmission. drx-RetransmissionTimerDL is a parameter for configuring the maximum time during which the UE is awake in order to receive downlink retransmission in a downlink HARQ procedure. drx-RetransmissionTimerUL is a parameter for configuring the maximum time during which the UE is awake in order to receive an uplink retransmission grant in an uplink HARQ procedure. drx-onDurationTimer, drx-Inactivity Timer, drx-Retransmission TimerDL, and drx-RetransmissionTimerUL may be configured as, for example, time, the number of subframes, the number of slots, and the like. ra-ContentionResolutionTimer is a parameter for monitoring the PDCCH in a random access procedure.
The inActive time 610 refers to a time configured such that the PDCCH is not monitored during the DRX operation or a time configured such that the PDCCH is not received, and the inActive time 610 may be obtained by subtracting the active timer 605 from the entire time during which the DRX operation is performed. If the UE does not monitor the PDCCH during the active time 605, the UE may enter a sleep or inActive state, thereby reducing power consumption.
The DRX cycle refers to the cycle at which the UE wakes up and monitors the PDCCH. That is, the DRX cycle refers to the time interval between when the UE monitors a PDCCH and when the next PDCCH is monitored, or the cycle at which on-duration occurs. There are two kinds of DRX cycles: a short DRX cycle and a long DRX cycle. The short DRX cycle may be optionally applied.
The long DRX cycle 625 is the longer cycle between two DRX cycles configured for the UE. While operating with long DRX, the UE restarts the drx-onDurationTimer 615 at a timepoint at which the long DRX cycle 625 has elapsed from the start point (for example, start symbol) of the drx-onDurationTimer 615. When operating at the long DRX cycle 625, the UE may start the drx-onDurationTimer 615 in a slot after drx-SlotOffset in a subframe satisfying Equation 1 below. As used herein, drx-SlotOffset refers to a delay before the drx-onDurationTimer 615 is started. The drx-SlotOffset may be configured, for example, as time, the number of slots, or the like.
wherein drx-LongCycleStartOffset may be used to define the long DRX cycle 625, and drx-StartOffset may be used to define a subframe to start the long DRX cycle 625. drx-LongCycleStartOffset may be configured as, for example, time, the number of subframes, the number of slots, or the like.
Next, downlink control information (DCI) in a 5G system will be described in detail.
In a 5G system, scheduling information regarding uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) is transferred from a base station to a UE through DCI. The UE may monitor, with regard to the PUSCH or PDSCH, a fallback DCI format and a non-fallback DCI format. The fallback DCI format may include a fixed field predefined between the base station and the UE, and the non-fallback DCI format may include a configurable field.
The DCI may be subjected to channel coding and modulation processes and then transmitted through a physical downlink control channel (PDCCH). A cyclic redundancy check is attached to the DCI message payload, and the CRC may be scrambled by 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, random access response, or the like. That is, the RNTI is not explicitly transmitted, but is transmitted while being included in a CRC calculation process. Upon receiving a DCI message transmitted through the PDCCH, the UE may identify the CRC by using the allocated RNTI. If the CRC identification result is right, the UE may know that the corresponding message has been transmitted to the UE.
For example, DCI for scheduling a PDSCH regarding system information (SI) may be scrambled by an SI-RNTI. DCI for scheduling a PDSCH regarding a random access response (RAR) message may be scrambled by an RA-RNTI. DCI for scheduling a PDSCH regarding a paging message may be scrambled by a P-RNTI. DCI for notifying of a slot format indicator (SFI) may be scrambled by an SFI-RNTI. DCI for notifying of transmit power control (TPC) may be scrambled by a TPC-RNTI. DCI for scheduling a UE-specific PDSCH or PUSCH may be scrambled by a cell RNTI (C-RNTI).
DCI format 0_0 may be used as fallback DCI for scheduling the PUSCH, and the CRC may be scrambled by a C-RNTI. DCI format 0_0 in which the CRC is scrambled by a C-RNTI may include the following pieces of information, for example:
DCI format 0_1 may be used as non-fallback DCI for scheduling the PUSCH, and the CRC may be scrambled by a C-RNTI. DCI format 0_1 in which the CRC is scrambled by a C-RNTI may include the following pieces of information, for example:
DCI format 1_0 may be used as fallback DCI for scheduling the PDSCH, and the CRC may be scrambled by a C-RNTI. DCI format 1_0 in which the CRC is scrambled by a C-RNTI may include the following pieces of information, for example:
DCI format 1_1 may be used as non-fallback DCI for scheduling the PDSCH, and the CRC may be scrambled by a C-RNTI. DCI format 1_1 in which the CRC is scrambled by a C-RNTI may include the following pieces of information, for example:
Hereinafter, a downlink control channel in a 5G communication system will be described in more detail with reference to the accompanying drawings.
A control resource set in 5G described above may be configured for a UE by a base station through higher layer signaling (for example, system information, master information block (MIB), radio resource control (RRC) signaling). The description that a control resource set is configured for a UE means that information such as a control resource set identity, the control resource set's frequency location, and the control resource set's symbol duration is provided. For example, the control resource set may include the following pieces of information:
In Table 8, tci-StatesPDCCH (simply referred to as transmission configuration indication (TCI) state) configuration information may include information of one or multiple synchronization signal (SS)/physical broadcast channel (PBCH) block index or channel state information reference signal (CSI-RS) index, which is quasi-co-located with a DMRS transmitted in a corresponding control resource set.
Provided that the basic unit of downlink control channel allocation in 5G is a control channel element 504 as illustrated in
The basic unit of the downlink control channel illustrated in
Search spaces may be classified into common search spaces and UE-specific search spaces. A group of UEs or all UEs may investigate a common search space of the PDCCH in order to receive cell-common control information such as a paging message or dynamic scheduling regarding system information. For example, PDSCH scheduling allocation information for transmitting an SIB including a cell operator information or the like may be received by investigating the common search space of the PDCCH. In the case of a common search space, a group of UEs or all UEs need to receive the PDCCH, and the same may thus be defined as a pre-promised set of CCEs. Scheduling allocation information regarding a UE-specific PDSCH or PUSCH may be received by investigating 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 UE's identity.
In 5G, a parameter regarding a search parameter regarding a PDCCH may be configured for the UE by the base station through higher layer signaling (for example, SIB, MIB, RRC signaling). For example, the base station may provide the UE with configurations such as the number of PDCCH candidates at each aggregation level L, the monitoring cycle regarding the search space, the monitoring occasion with regard to each symbol in a slot regarding the search space, the search space type (common search space or UE-specific search space), a combination of an RNTI and a DCI format to be monitored in the corresponding search space, a control resource set index for monitoring the search space, and the like. For example, the parameter may include the following pieces of information:
According to configuration information, the base station may configure one or multiple search space sets for the UE. According to some embodiments, the base station may configure search space set 1 and search space set 2 for the UE, may configure DCI format A scrambled by an a X-RNTI to be monitored in a common search space in search space set 1, and may configure DCI format B scrambled by a Y-RNTI to be monitored in a UE-specific search space in search space set 2.
According to configuration information, one or multiple search space sets may exist in a common search space or a UE-specific search space. For example, search space set #1 and search space set #2 may be configured as a common search space, and search space set #3 and search space set #4 may be configured as a UE-specific search space.
Combinations of DCI formats and RNTIs given below may be monitored in a common search space. Obviously, the example given below is not limiting.
DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI;
DCI format 2_0 with CRC scrambled by SFI-RNTI;
DCI format 2_1 with CRC scrambled by INT-RNTI;
DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI; and DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI;
Combinations of DCI formats and RNTIs given below may be monitored in a UE-specific search space. Obviously, the example given below is not limiting.
DCI format 0_0/1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI;
DCI format 1 0/1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI
Enumerated RNTIs may follow the definition and usage given below:
Cell RNTI (C-RNTI): used to schedule a UE-specific PDSCH;
Temporary cell RNTI (TC-RNTI): used to schedule a UE-specific PDSCH;
Configured scheduling RNTI (CS-RNTI): used to schedule a semi-statically configured UE-specific PDSCH;
Random access RNTI (RA-RNTI): used to schedule a PDSCH in a random access step;
Paging RNTI (P-RNTI): used to schedule a PDSCH in which paging is transmitted;
System information RNTI (SI-RNTI): used to schedule a PDSCH in which system information is transmitted;
Interruption RNTI (INT-RNTI): used to indicate whether a PDSCH is punctured
Transmit power control for PUSCH RNTI (TPC-PUSCH-RNTI): used to indicate a power control command regarding a PUSCH;
Transmit power control for PUCCH RNTI (TPC-PUCCH-RNTI): used to indicate a power control command regarding a PUCCH; and
Transmit power control for SRS RNTI (TPC-SRS-RNTI): used to indicate a power control command regarding an SRS.
The DCI formats enumerated above may follow the definitions given below:
In 5G, the search space at aggregation level L in connection with control resource set p and search space set s may be expressed by Equation 2 below:
The
value may correspond to 0 in the case of a common search space.
The
value may correspond to a value changed by the UE's identity (C-RNTI or ID configured for the UE by the base station) and the time index in the case of a UE-specific search space.
In 5G, multiple search space sets may be configured by different parameters (for example, parameters in Table 9), and the group of search space sets monitored by the UE at each timepoint may differ. For example, if search space set #1 is configured at by X-slot cycle, if search space set #2 is configured at by Y-slot cycle, and if X and Y are different, the UE may monitor search space set #1 and search space set #2 both in a specific slot, and may monitor one of search space set #1 and search space set #2 both in another specific slot.
The UE may perform UE capability reporting at each subcarrier spacing with regard to a case in which the same has multiple PDCCH monitoring occasions inside a slot, and the concept “span” may be used in this regard. A span refers to consecutive symbols configured such that the UE can monitor the PDCCH inside the slot, and each PDCCH monitoring occasion is inside one span. A span may be described by (X,Y) wherein X refers to the minimum number of symbols by which the first symbols of two consecutive spans are spaced apart from each other, and Y refers to the number of consecutive symbols configured such that the PDCCH can be monitored inside one span. The UE may monitor the PDCCH in a range inside a span corresponding to Y symbols from the first symbol of the span.
The slot location at which the above-described common search space and the UE-specific search space are positioned is indicated by parameter “monitoringSymbolsWitninSlot” in Table 11-1, and the symbol location inside the slot is indicated as a bitmap through parameter “monitoringSymbolsWithinSlot” in Table 9. Meanwhile, the symbol location inside a slot at which the UE can monitor search spaces may be reported to the base station through the following UE capabilities:
The UE may report whether the above-described capability 2 and/or capability 3 are supported and relevant parameters to the base station. The base station may allocate time-domain resources to the common search space and the UE-specific search space, based on the UE capability report. During the resource allocation, the base station may ensure that the MO is not positioned at a location at which the UE cannot monitor the same.
If there are multiple search space sets configured for a UE, the following conditions may be considered in connection with a method for determining a search space set to be monitored by the UE.
If the value of “monitoringCapabilityConfig-r16” (higher layer signaling) has been configured to be “r15monitoringcapability” for the UE, the UE defines maximum values regarding the number of PDCCH candidates that can be monitored and the number of CCEs constituting the entire search space (as used herein, the entire search space refers to the entire CCE set corresponding to a union domain of multiple search space sets) with regard to each slot. If the value of “monitoringCapabilityConfig-r16” has been configured to be “r16monitoringcapability,” the UE defines maximum values regarding the number of PDCCH candidates that can be monitored and the number of CCEs constituting the entire search space (as used herein, the entire search space refers to the entire CCE set corresponding to a union domain of multiple search space sets) with regard to each span.
According to the above-mentioned higher layer signaling configuration value, the maximum number Mu of PDCCH candidates that the UE can monitor may follow Table 12-1 given below if the same is defined with reference to a slot in a cell configured to have a subcarrier spacing of 15 0.24 kHz, and may follow Table 12-2 given below if the same is defined with reference to a span.
According to the above-mentioned higher layer signaling configuration value, the maximum number Cμ of CCEs constituting the entire search space (as used herein, the entire search space refers to the entire CCE set corresponding to a union domain of multiple search space sets) may follow Table 12-3 given below if the same is defined with reference to a slot in a cell configured to have a subcarrier spacing of 15.24 kHz, and may follow Table 12-4 given below if the same is defined with reference to a span.
For convenience of description, a situation satisfying both conditions 1 and 2 above at a specific timepoint will be defined as “condition A.” Therefore, the description that condition A is not satisfied may mean that at least one of conditions 1 and 2 above is not satisfied.
According to the configuration of search space sets of the base station, a case in which condition A is not satisfied may occur at a specific timepoint. If condition A is not satisfied at a specific timepoint, the UE may select and monitor only some of search space sets configured to satisfy condition A at the corresponding timepoint, and the base station may transmit a PDCCH to the selected search space set.
A method for selecting some search spaces from all configured search space sets may follow methods given below:
If condition A regarding a PDCCH fails to be satisfied at a specific timepoint (slot), the UE (or the base station) may preferentially select a search space set having a search space type configured as a common search space, among search space sets existing at the corresponding timepoint, over a search space set configured as a UE-specific search space.
If all search space sets configured as common search spaces have been selected (that is, if condition A is satisfied even after all search spaces configured as common search spaces have been selected), the UE (or the bae station) may select search space sets configured as UE-specific search spaces. If there are multiple search space sets configured as UE-specific search spaces, a search space set having a lower search space set index may have a higher priority. UE-specific search space sets may be selected as long as condition A is satisfied, in view of the priority.
In a wireless communication system, one or more different antenna ports (which may be replaced with one or more channels, signals, and combinations thereof, but may be referred to as different antenna ports, as a whole, for convenience of description of the disclosure) may be associated with each other by a quasi-co-location (QCL) configuration as in Table 10 below. A TCI state is for publishing the QCL relation between a PDCCH (or a PDCCH DMRS) and another RS or channel. The description that a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed with each other 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 form the antenna port B. The QCL needs to be associated with different parameters according to the situation such as 1) time tracking influenced by average delay and delay spread, 2) frequency tracking influenced by Doppler shift and Doppler spread, 3) radio resource management (RRM) influenced by average gain, or 4) beam management (BM) influenced by a spatial parameter. Accordingly, four types of QCL relations are supported in NR as in Table 13 below:
The spatial RX parameter may refer to some or all of various parameters as a whole, such as angle of arrival (AoA), power angular spectrum (PAS) of AoA, angle of departure (AoD), PAS of AoD, transmit/receive channel correlation, transmit/receive beamforming, and spatial channel correlation.
The QCL relation may be configured for the UE through RRC parameter TCI-state and QCL-info as in Table 14 below. Referring to Table 14, the base station may configure one or more TCI states for the UE, thereby informing of a maximum of two kinds of QCL relations (qcl-Type1, qcl-Type2) regarding the RS that refers to the ID of the TCI state, that is, the target RS. Each piece of QCL information (QCL-Info) that each TCI state includes the serving cell index and the BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference BS, and a QCL type as in Table 13 above.
Tables 15-1 to 15-5 below enumerate valid TCI state configurations according to the target antenna port type.
Table 15-1 enumerates valid TCI state configurations when the target antenna port is a CSI-RS for tracking (TRS). The TRS refers to an NZP CSI-RS which has no repetition parameter configured therefor, and trs-Info of which is configured as “true,” among CRI-RSs. In Table 15-1, configuration no. 3 may be used for an aperiodic TRS.
Table 15-2 enumerates valid TCI state configurations when the target antenna port is a CSI-RS for CSI. The CSI-RS for CSI refers to an NZP CSI-RS which has no parameter indicating repetition (for example, repetition parameter) configured therefor, and trs-Info of which is not configured as “true,” among CRI-RSs.
Table 15-3 enumerates valid TCI state configurations when the target antenna port is a CSI-RS for beam management (BM) (which has the same meaning as CSI-RS for L1 RSRP reporting). The CSI-RS for BM refers to an NZP CSI-RS which has a repetition parameter configured to have a value of “on” or “off,” and trs-Info of which is not configured as “true,” among CRI-RSs.
Table 15-4 enumerates valid TCI state configurations when the target antenna port is a PDCCH DMRS.
Table 15-5 enumerates valid TCI state configurations when the target antenna port is a PDSCH DMRS.
According to a representative QCL configuration method based on Tables 15-1 to 15-5 above, the target antenna port and reference antenna port for each step are configured and operated such as “SSB”->“TRS”->“CSI-RS for CSI, or CSI-RS for BM, or PDCCH DMRS, or PDSCH DMRS.” Accordingly, it is possible to help the UE's receiving operation by associating statistical characteristics that can be measured from the SSB and TRS with respective antenna ports.
Specific TCI state combinations applicable to a PDCCH DMRS antenna port are given in Table 16 below. The fourth row in Table 16 corresponds to a combination assumed by the UE before RRC configuration, and no configuration is possible after the RRC.
In NR, a hierarchical signaling method as illustrated in
The base station may configure one or multiple TCI states for the UE with regard to a specific control resource set, and may activate one of the configured TCI states through a MAC CE activation command. For example, if {TCI state #0, TCI state #1, TCI state #2} are configured as TCI states for control resource set #1, the base station may transmit an activation command to the UE through a MAC CE such that TCI state #0 is assumed as the TCI state regarding control resource set #1. Based on the activation command regarding the TCI state received through the MAC CE, the UE may correctly receive the DMRS of the corresponding control resource set, based on QCL information in the activated TCI state.
With regard to a control resource set having a configured index of 0 (control resource set #0), if the UE has failed to receive a MAC CE activation command regarding the TCI state of control resource set #0, the UE may assume that the DMRS transmitted in control resource set #0 has been QCL-ed with a SS/PBCH block identified in the initial access process, or in a non-contention-based random access process not triggered by a PDCCH command.
With regard to a control resource set having a configured index value other than 0 (control resource set #X), if the UE has no TCI state configured regarding control resource set #X, or if the UE has one or more TCI states configured therefor but has failed to receive a MAC CE activation command for activating one thereof, the UE may assume that the DMRS transmitted in control resource set #X has been QCL-ed with a SS/PBCH block identified in the initial access process.
Hereinafter, operations for determining QCL priority regarding a PDCCH will be described in detail.
If multiple control resource sets which operate according to carrier aggregation inside a single cell or band and which exist inside a single or multiple in-cell activated bandwidth parts overlap temporally while having identical or different QCL-TypeD characteristics in a specific PDCCH monitoring occasion, the UE may select a specific control resource set according to a QCL priority determining operation and may monitor control resource sets having the same QCL-TypeD characteristics as the corresponding control resource set. That is, if multiple control resource sets overlap temporally, only one QCL-TypeD characteristic can be received. The QCL priority may be determined by the following criteria:
As described above, if one criterion among the criteria is not satisfied, the next criterion is applied. For example, if control resource sets overlap temporally in a specific PDCCH monitoring occasion, and if all control resource sets are not connected to a common search space but connected to a UE-specific search space (that is, if criterion 1 is not satisfied), the UE may omit application of criterion 1 and apply criterion 2.
When selecting control resource set according to the above-mentioned criteria, the UE may additionally consider the two aspects with regard to QCL information configured for the control resource set. Firstly, if control resource set 1 has CSI-RS 1 as a reference signal having a relation of QCL-TypeD, if this CSI-RS 1 has a relation of QCL-TypeD with reference signal SSB 1, and if another control resource set 2 has a relation of QCL-TypeD with reference signal SSB 1, the UE may consider that the two control resource sets 1 and 2 have different QCL-TypeD characteristics. Secondly, if control resource set 1 has CSI-RS 1 configured for cell 1 as a reference signal having a relation of QCL-TypeD, if this CSI-RS 1 has a relation of QCL-TypeD with reference signal SSB 1, if control resource set 2 has a relation of QCL-TypeD with reference signal CSI-RS 2 configured for cell 2, and if this CSI-RS 2 has a relation of QCL-TypeD with the same reference signal SSB 1, the UE may consider that the two control resource sets have the same QCL-TypeD characteristics.
Hereinafter, a rate matching operation and a puncturing operation will be described in detail.
If time and frequency resource A to transmit symbol sequence A overlaps time and frequency resource B, a rate matching or puncturing operation may be considered as an operation of transmitting/receiving channel A in view of resource C (area in which resource A and resource B overlap). Specific operations may follow the following description:
The UE may assess resource A and resource B from scheduling information regarding symbol sequence A from the base station, thereby assessing resource C (area in which resource A and resource B overlap). The UE may receive symbol sequence A based on an assumption that symbol sequence A has been mapped and transmitted in the remaining area other than resource C among the entire resource A. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, the UE may receive symbol sequence A based on an assumption that the same has been successively mapped to remaining resources {resource #1, resource #2, resource #4} other than {resource #3} (corresponding to resource C) among resource A. Consequently, the UE may perform a series of following receiving operations based on an assumption that symbol sequence {symbol #1, symbol #2, symbol #3} has been transmitted after being mapped to {resource #1, resource #2, resource #4}, respectively.
If there is resource C (area overlapping resource B) among the entire resource A which is to be used to transmit symbol sequence A to the UE, the base station may map symbol sequence A to the entire resource A, but may not perform transmission in the resource area corresponding to resource C, and may perform transmission with regard to only the remaining resource area other than resource C among resource A. For example, assuming that symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol4}, resource A is {resource #1, resource #2, resource #3, resource #4}, and resource B is {resource #3, resource #5}, the base station may map symbol sequence {symbol #1, symbol #2, symbol #3, symbol #4} to resource A {resource #1, resource #2, resource #3, resource #4}, respectively, may transmit only symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to remaining resources {resource #1, resource #2, resource #4} other than {resource #3} (corresponding to resource C) among resource A, and may not transmit {symbol #3} mapped to {resource #3} (corresponding to resource C). Consequently, the base station may transmit symbol sequence {symbol #1, symbol #2, symbol #4} after mapping the same to {resource #1, resource #2, resource #4}, respectively.
The UE may assess resource A and resource B from scheduling information regarding symbol sequence A from the base station, thereby assessing resource C (area in which resource A and resource B overlap). The UE may receive symbol sequence A based on an assumption that symbol sequence A has been mapped to the entire resource A but transmitted only in the remaining area other than resource C among the resource area A. For example, if symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol4}, if resource A is {resource #1, resource #2, resource #3, resource #4}, and if resource B is {resource #3, resource #5}, the UE may assume that symbol sequence A {symbol #1, symbol #2, symbol #3, symbol4} is mapped to resource A {resource #1, resource #2, resource #3, resource #4}, respectively, but {symbol #3} mapped to {resource #3} (corresponding to resource C) is not transmitted. Based on the assumption that symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to remaining resources {resource #1, resource #2, resource #4} other than {resource #3} (corresponding to resource C) among resource A has been mapped and transmitted, the UE may receive the same. Consequently, the UE may perform a series of following receiving operations based on an assumption that symbol sequence {symbol #1, symbol #2, symbol #4} has been transmitted after being mapped to {resource #1, resource #2, resource #4}, respectively.
Hereinafter, a method for configuring a rate matching resource for the purpose of rate matching in a 5G communication system will be described. Rate matching refers to adjusting the size of a signal in view of the amount of resources that can be used to transmit the signal. For example, data channel rate matching may mean that a data channel is not mapped and transmitted with regard to specific time and frequency resource domains, and the size of data is adjusted accordingly.
The base station may dynamically notify the UE, through DCI, of whether the PDSCH may be rate-matched in the configured rate matching resource part through an additional configuration (corresponding to “rate matching indicator” inside DCI format described above). Specifically, the base station may select some from the configured rate matching resources and group them into a rate matching resource group, and may indicate, to the UE, whether the PDSCH is rate-matched with regard to each rate matching resource group through DCI by using a bitmap type. For example, if four rate matching resources RMR #1, RMR #2, RMR #3, and RMR #4 are configured, the base station may configure a rate matching groups RMG #1={RMR #1, RMR #2}, RMG #2={RMR #3, RMR #4}, and may indicate, to the UE, whether rate matching occurs in RMG #1 and RMG #2, respectively, through a bitmap by using two bits inside the DCI field. For example, “1” may mean that rate matching is to be conducted, and “0” may mean that rate matching is not to be conducted.
5G supports granularity of “RB symbol level” and “RE level” as a method for configuring the above-described rate matching resources for a UE. More specifically, the following configuration method may be followed:
The UE may have a maximum of four RateMatchPatterns configured per each bandwidth part through higher layer signaling, and one RateMatchPattern may include the following content:
The UE may have the following content configured through higher layer signaling:
Next, a rate matching process regarding the above-mentioned LTE CRS will be described in detail. For coexistence between long term evolution (LTE) and new RAT (NR) (LTE-NR coexistence), NR provides an NR UE with a function for configuring the pattern of cell-specific reference signal (CRS) of LTE. More specifically, the CRS pattern may be provided by RRC signaling including at least one parameter inside ServingCellConfig 1E (information element) or ServingCellConfigCommon IE. Examples of the parameter may include Ite-CRS-ToMatchAround, lte-CRS-PatternList1-r16, Ite-CRS-PatternList2-r16, crs-RateMatch-PerCORESETPoolIndex-r16, and the like.
Rel-15 NR provides a function such that one CRS pattern can be configured per serving cell through parameter lte-CRS-ToMatchAround. In Rel-16 NR, the above function has been expanded such that multiple CRS patterns can be configured per serving cell. More specifically, a UE having a single-TRP (transmission and reception point) configuration may now have one CRS pattern configured per one LTE carrier, and a UE having a multi-TRP configuration may now have two CRS patterns configured per one LTE carrier. For example, the UE having a single-TRP configuration may have a maximum of three CRS patterns configured per serving cell through parameter lte-CRS-PatternList1-r16. As another example, the UE having a multi-TRP configuration may have a CRS configured for each TRP. That is, the CRS pattern regarding TRP1 may be configured through parameter lte-CRS-PatternList1-r16, and the CRS pattern regarding TRP2 may be configured through parameter lte-CRS-PatternList2-r16. Meanwhile, if two TRPs are configured as above, whether the CRS patterns of TRP1 and TRP2 are both to be applied to a specific physical downlink shared channel (PDSCH) or only the CRS pattern regarding one TRP is to be applied is determined through parameter crs-RateMatch-PerCORESETPoolIndex-r16. If parameter crs-RateMatch-PerCORESETPoolIndex-r16 is configured “enabled,” only the CRS pattern of one TRP is applied, and both CRS patterns of the two TRPs are applied in other cases.
Table 17 shows a ServingCellConfig 1E including the CRS patterns, and Table 18 shows a RateMatchPatternLTE-CRS IE including at least one parameter regarding CRS patterns.
[PDSCH: regarding frequency resource allocation]
Referring to
In the case 13-05 in which the UE is configured to use only resource type 1 through higher layer signaling, partial DCI includes frequency domain resource allocation information including [log2(NRBDL,BWP(NRBDL,BWP+1)/2] bits. The condition for this will be described later. The base station may thereby configure a starting VRB 13-20 and the length 13-25 of a frequency domain resource allocated continuously therefrom.
In the case 13-10 in which the UE is configured to use both resource type 0 and resource type 1 through higher layer signaling, partial DCI for allocating a PDSCH to the corresponding UE includes frequency domain resource allocation information including as many bits as the larger value 13-35 between the payload 13-15 for configuring resource type 0 and the payload 13-20 and 13-25 for configuring resource type 1. The condition for this will be described later. One bit may be added to the foremost part (MSB) of the frequency domain resource allocation information inside the DCI. If the bit has the value of “0,” use of resource type 0 may be indicated, and if the bit has the value of “1,” use of resource type 1 may be indicated.
Hereinafter, a time domain resource allocation method regarding a data channel in a next-generation mobile communication system (5G or NR system) will be described.
A base station may configure table regarding time domain resource allocation information regarding a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH) for a UE through higher layer signaling (for example, RRC signaling). A table including a maximum of maxNrofDL-Allocations=16 entries may be configured for the PDSCH, and a table including a maximum of maxNrofUL-Allocations=16 entries may be configured for the PUSCH. In an embodiment, the time domain resource allocation information may include PDCCH-to-PDSCH slot timing (corresponding to a slot-unit time interval between a timepoint at which a PDCCH is received and a timepoint at which a PDSCH scheduled by the received PDCCH is transmitted; labeled KO), PDCCH-to-PUSCH slot timing (corresponding to a slot-unit time interval between a timepoint at which a PDCCH is received and a timepoint at which a PUSCH scheduled by the received PDCCH is transmitted; labeled K2), information regarding the location and length of the start symbol by which a PDSCH or PUSCH is scheduled inside a slot, the mapping type of a PDSCH or PUSCH, and the like. For example, information such as in Table 20 or Table 21 below may be transmitted from the base station to the UE.
The base station may notify the UF of one of the entries of the table regarding time domain resource allocation information described above through L1 signaling (for example, DCI) (for example, “time domain resource allocation” field inside DCI may indicate the same). The UE may acquire time domain resource allocation information regarding a PDSCH or PUSCH, based on the DCI acquired from the base station.
Referring to
Referring to
Next, a PDSCH processing time (PDSCH processing procedure time) will be described. When the base station schedules the UE to transmit a PDSCH by using DCI format 1_0, 1_1 or 1_2, the UE may need a PDSCH processing time for receiving a PDSCH by applying a transmission method (modulation/demodulation and coding indication index (MCS), demodulation reference signal-related information, time and frequency resource allocation information, and the like) indicated through DCI. The PDSCH processing time has been defined in NR in view thereof. The PDSCH processing time of the UE may follow [Equation 3] given below:
Each parameter in Tproc,1 described above in Equation 3 may have the following meaning:
If the location of the first uplink transmission symbol of a PUCCH including HARQ-ACK information (in connection with the corresponding location, K1 defined as the HARQ-ACK transmission timepoint, a PUCCH resource used to transmit the HARQ-ACK, and the timing advance effect may be considered) does not start earlier than the first uplink transmission symbol that comes after the last symbol of the PDSCH over a time of Tproc,1, the UE needs to transmit a valid HARQ-ACK message. That is, the UE needs to transmit a PUCCH including a HARQ-ACK only if the PDSCH processing time is sufficient. The UE cannot otherwise provide the base station with valid HARQ-ACK information corresponding to the scheduled PDSCH. The Tproc, 1 may be used in the case of either a normal or an expanded CP. In the case of a PDSCH having two PDSCH transmission locations configured inside one slot, d1, 1 is calculated with reference to the first PDSCH transmission location inside the corresponding slot.
Next, in the case of cross-carrier scheduling in which the numerology (μPDCCH) by which a scheduling PDCCH is transmitted and the numerology (μPDSCH) by which a PDSCH scheduled by the corresponding PDCCH is transmitted are different from each other, the PDSCH reception reparation time (Npdsch) of the UE defined with regard to the time interval between the PDCCH and PDSCH will be described.
If μPDCCH<μPDSCH, the scheduled PDSCH cannot be transmitted before the first symbol of the slot coming after Npdsch symbols from the last symbol of the PDCCH that scheduled the corresponding PDSCH. The transmission symbol of the corresponding PDSCH may include a DM-RS.
If μPDCCH>μPDSCH, the scheduled PDSCH may be transmitted after Npdsch symbols from the last symbol of the PDCCH that scheduled the corresponding PDSCH. The transmission symbol of the corresponding PDSCH may include a DM-RS.
Next, a beam configuration method regarding a PDSCH will be described.
The meaning of respective fields inside the MAC CE and values configurable for respective fields are as follows:
Next, a PUSCH transmission scheduling scheme will be described. PUSCH transmission may be dynamically scheduled by a UL grant inside DCI, or operated by means of configured grant Type 1 or Type 2. Dynamic scheduling indication regarding PUSCH transmission can be made by DCI format 0_0 or 0_1.
Configured grant Type 1 PUSCH transmission may be configured semi-statically by receiving configuredGrantConfig including rrc-ConfiguredUplinkGrant in [Table 25] through higher layer signaling, without receiving a UL grant inside DCI. Configured grant Type 2 PUSCH transmission may be scheduled semi-persistently by a UL grant inside DCI after receiving configuredGrantConfig not including rrc-ConfiguredUplinkGrant in [Table 25] through higher layer signaling. If PUSCH transmission is operated by a configured grant, parameters applied to the PUSCH transmission are applied through configuredGrantConfig (higher layer signaling) in [Table 25] except for dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling of UCI-OnPUSCH, which are provided by pusch-Config in [Table 26], which is higher layer signaling. If provided with transformPrecoder inside configuredGrantConfig (higher layer signaling) in [Table 25], the UE applies tp-pi2BPSK inside pusch-Config in [Table 26] to PUSCH transmission operated by a configured grant.
Next, a PUSCH transmission method will be described. The DMRS antenna port for PUSCH transmission is identical to an antenna port for SRS transmission. PUSCH transmission may follow a codebook-based transmission method and a non-codebook-based transmission method according to whether the value of txConfig inside pusch-Config in [Table 26], which is higher layer signaling, is “codebook” or “nonCodebook.”
As described above, PUSCH transmission may be dynamically scheduled through DCI format 0_0 or 0_1, and may be semi-statically configured by a configured grant. Upon receiving indication of scheduling regarding PUSCH transmission through DCI format 0_0, the UE perform beam configuration for PUSCH transmission by using pucch-spatialRelationInfoID corresponding to a UE-specific PUCCH resource corresponding to the minimum ID inside an activated uplink BWP inside a serving cell, and the PUSCH transmission is based on a single antenna port. The UE does not expect scheduling regarding PUSCH transmission through DCI format 0_0 inside a BWP having no configured PUCCH resource including pucch-spatialRelationInfo. If the UE has no configured txConfig inside pusch-Config in [Table 26], the UE does not expect scheduling through DCI format 0_1.
Next, codebook-based PUSCH transmission will be described. The codebook-based PUSCH transmission may be dynamically scheduled through DCI format 0_0 or 0_1, and may be operated semi-statically by a configured grant. If a codebook-based PUSCH is dynamically scheduled through DCI format 0_1 or configured semi-statically by a configured grant, the UE determine a precoder for PUSCH transmission, based on an SRS resource indicator (SRI), a transmission precoding matrix indicator (TPMI), and a transmission rank (the number of PUSCH transmission layers).
The SRI may be given through the SRS resource indicator (a field inside DCI) or configured through srs-ResourceIndicator (higher layer signaling). During codebook-based PUSCH transmission, the UE has at least one SRS resource configured therefor, and may have a maximum of two SRS resources configured therefor. If the UE is provided with an SRI through DCI, the SRS resource indicated by the SRI refers to the SRS resource corresponding to the SRI among SRS resources transmitted prior to the PDCCH including the SRI. In addition, the TPMI and the transmission rank may be given through “precoding information and number of layers” (a field inside DCI) or configured through precodingAndNumberOfLayers (higher layer signaling). The TPMI is used to indicate a precoder applied to PUSCH transmission. If one SRS resource is configured for the UE, the TPMI is used to indicate a precoder to be applied in the configured SRS resource. If multiple SRS resources are configured for the UE, the TPMI is used to indicate a precoder to be applied in an SRS resource indicated through the SRI.
The precoder to be used for PUSCH transmission is selected from an uplink codebook having the same number of antenna ports as the value of nrofSRS-Ports inside SRS-Config (higher layer signaling). In connection with codebook-based PUSCH transmission, the UE determines a codebook subset, based on codebookSubset inside pusch-Config (higher layer signaling) and TPMI. The codebookSubset inside pusch-Config (higher layer signaling) may be configured to be one of “fully AndPartialAndNonCoherent,” “partial AndNonCoherent,” or “noncoherent,” based on UE capability reported by the UE to the base station. If the UE reported “partial AndNonCoherent” as UE capability, the UE does not expect that the value of codebook Subset (higher layer signaling) will be configured as “fully AndPartialAndNonCoherent.” In addition, if the UE reported “nonCoherent” as UE capability, UE does not expect that the value of codebook Subset (higher layer signaling) will be configured as “fully AndPartial AndNonCoherent” or “partialAndNonCoherent.” If nrofSRS-Ports inside SRS-ResourceSet (higher layer signaling) indicates two SRS antenna ports, UE does not expect that the value of codebook Subset (higher layer signaling) will be configured as “partialAndNonCoherent.”
The UE may have one SRS resource set configured therefor, wherein the value of usage inside SRS-ResourceSet (higher layer signaling) is “codebook,” and one SRS resource may be indicated through an SRI inside the SRS resource set. If multiple SRS resources are configured inside the SRS resource set wherein the value of usage inside SRS-ResourceSet (higher layer signaling) is “codebook,” the UE expects that the value of nrofSRS-Ports inside SRS-Resource (higher layer signaling) is identical with regard to all SRS resources.
The UE transmit, to the base station, one or multiple SRS resources included in the SRS resource set wherein the value of usage is configured as “codebook” according to higher layer signaling, and the base station selects one from the SRS resources transmitted by the UE and instructs the UE to transmit a PUSCH by using transmission beam information of the corresponding SRS resource. In connection with the codebook-based PUSCH transmission, the SRI is used as information for selecting the index of one SRS resource, and is included in DCI. Additionally, the base station adds information indicating the rank and TPMI to be used by the UE for PUSCH transmission to the DCI. By using the SRS resource indicated by the SRI, the UE applies the precoder indicated by the rank and TPMI indicated based on the transmission beam of the corresponding SRS resource, thereby performing PUSCH transmission.
Next, non-codebook-based PUSCH transmission will be described. The non-codebook-based PUSCH transmission may be dynamically scheduled through DCI format 0_0 or 0_1, and may be operated semi-statically by a configured grant. If at least one SRS resource is configured inside an SRS resource set wherein the value of usage inside SRS-ResourceSet (higher layer signaling) is “nonCodebook,” non-codebook-based PUSCH transmission may be scheduled for the UE through DCI format 0_1.
With regard to the SRS resource set wherein the value of usage inside SRS-ResourceSet (higher layer signaling) is “nonCodebook,” one connected NZP CSI-RS resource (non-zero power CSI-RS) may be configured for the UE. The UE may calculate a precoder for SRS transmission by measuring the NZP CSI-RS resource connected to the SRS resource set. If the difference between the last received symbol of an aperiodic NZP CSI-RS resource connected to the SRS resource set and the first symbol of aperiodic SRS transmission in the UE is less than 42 symbols, the UE does not expect that information regarding the precoder for SRS transmission will be updated.
If the configured value of resourceType inside SRS-ResourceSet (higher layer signaling) is “aperiodic,” the connected NZP CSI-RS is indicated by an SRS request which is a field inside DCI format 0_1 or 1_1. If the connected NZP CSI-RS resource is an aperiodic NZP CSI-RS resource, the existence of the connected NZP CSI-RS is indicated with regard to the case in which the value of SRS request (a field inside DCI format 0_1 or 1_1) is not “00.” The corresponding DCI may not indicate cross carrier or cross BWP scheduling. In addition, if the value of SRS request indicates the existence of a NZP CSI-RS, the NZP CSI-RS is positioned in the slot used to transmit the PDCCH including the SRS request field. In this case, TCI states configured for the scheduled subcarrier are not configured as QCL-TypeD.
If there is a periodic or semi-persistent SRS resource set configured, the connected NZP CSI-RS may be indicated through associatedCSI-RS inside SRS-ResourceSet (higher layer signaling). With regard to non-codebook-based transmission, the UE does not expect that spatialRelationInfo which is higher layer signaling regarding the SRS resource and associatedCSI-RS inside SRS-ResourceSet (higher layer signaling) will be configured together.
If multiple SRS resources are configured for the UE, the UE may determine a precoder to be applied to PUSCH transmission and the transmission rank, based on an SRI indicated by the base station. The SRI may be indicated through the SRS resource indicator (a field inside DCI) or configured through srs-ResourceIndicator (higher layer signaling). Similarly to the above-described codebook-based PUSCH transmission, if the UE is provided with the SRI through DCI, the SRS resource indicated by the corresponding SRI refers to the SRS resource corresponding to the SRI, among SRS resources transmitted prior to the PDCCH including the corresponding SRI. The UE may use one or multiple SRS resources for SRS transmission, and the maximum number of SRS resources that can be transmitted simultaneously in the same symbol inside one SRS resource set and the maximum number of SRS resources are determined by UE capability reported to the base station by the UE. SRS resources simultaneously transmitted by the UE occupy the same RB. The UE configures one SRS port for each SRS resource. There may be only one configured SRS resource set wherein the value of usage inside SRS-ResourceSet (higher layer signaling) is “nonCodebook,” and a maximum of four SRS resources can be configured for non-codebook-based PUSCH transmission.
The base station transmits one NZP-CSI-RS connected to the SRS resource set to the UE, and the UE calculates the precoder to be used when transmitting one or multiple SRS resources inside the corresponding SRS resource set, based on the result of measurement when the corresponding NZP-CSI-RS is received. The UE applies the calculated precoder when transmitting, to the base station, one or multiple SRS resources inside the SRS resource set wherein the configured usage is “nonCodebook,” and the base station selects one or multiple SRS resources from the received one or multiple SRS resources. In connection with the non-codebook-based PUSCH transmission, the SRI indicates an index that may express one SRS resource or a combination of multiple SRS resources, and the SRI is included in DCI. 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 transmits the PUSCH by applying the precoder applied to SRS resource transmission to each layer.
[PUSCH: preparation procedure time]
Next, a PUSCH preparation procedure time will be described. If a base station schedules a UE so as to transmit a PUSCH by using DCI format 0_0, 0_1, or 0_2, the UE may require a PUSCH preparation procedure time such that a PUSCH is transmitted by applying a transmission method (SRS resource transmission precoding method, the number of transmission layers, spatial domain transmission filter) indicated through DCI. The PUSCH preparation procedure time is defined in NR in view thereof. The PUSCH preparation procedure time of the UE may follow [Equation 4] given below:
Each parameter in Tproc,2 described above in Equation 4 may have the following meaning:
The base station and the UE determine that the PUSCH preparation procedure time is insufficient if the first symbol of a PUSCH starts earlier than the first uplink symbol in which a CP starts after Tproc,2 from the last symbol of a PDCCH including DCI that schedules the PUSCH, in view of the influence of timing advance between the uplink and the downlink and time domain resource mapping information of the PUSCH scheduled through the DCI. Otherwise, the base station and the UE determine that the PUSCH preparation procedure time is sufficient. The UE may transmit the PUSCH only if the PUSCH preparation procedure time is sufficient, and may ignore the DCI that schedules the PUSCH if the PUSCH preparation procedure time is insufficient.
Hereinafter, repeated transmission of an uplink data channel in a 5G system will be described in detail. A 5G system supports two types of methods for repeatedly transmitting an uplink data channel, PUSCH repeated transmission type A and PUSCH repeated transmission type B. One of PUSCH repeated transmission type A and type B may be configured for a UE through higher layer signaling.
PUSCH repeated transmission type A
and the symbol starting in that slot is given by mod (S+n·L, Nsymbslot) The slot in which the nth nominal repetition ends is given by
and the symbol ending in that slot is given by mod (S+(n+1)·L−1, Nsymbslot) this regard, n=0, . . . , numberofrepetitions-1, S refers to the start symbol of the configured uplink data channel, and L refers to the symbol length of the configured uplink data channel. K, refers to the slot in which PUSCH transmission starts, and Nsymbslot refers to the number of symbols per slot.
After an invalid symbol is determined, the UE may consider, with regard to each nominal repetition, that symbols other than the invalid symbol are valid symbols. If one or more valid symbols are included in each nominal repetition, the nominal repetition may include one or more actual repetitions. Each actual repetition includes a set of consecutive valid symbols available for PUSCH repeated transmission type B in one slot.
In addition, with regard to PUSCH repeated transmission, additional methods may be defined in NR Release 16 with regard to UL grant-based PUSCH transmission and configured grant-based PUSCH transmission, across slot boundaries, as follows:
Hereinafter, frequency hopping of a physical uplink shared channel (PUSCH) in a 5G system will be described in detail.
5G supports two kinds of PUSCH frequency hopping methods with regard to each PUSCH repeated transmission type. In PUSCH repeated transmission type A, intra-slot frequency hopping and inter-slot frequency hopping are supported, and in PUSCH repeated transmission type B, inter-repetition frequency hopping and inter-slot frequency hopping are supported.
According to the inter-slot frequency hopping method supported in PUSCH repeated transmission type A, a UE transmits allocated resources in the frequency domain, after changing the same by a configured frequency offset, by two hops in one slot. The start RB of each hop in connection with intra-slot frequency hopping may be expressed by Equation 5 below:
In Equation 5, i=0 and i=1 indicate the first and second hops, respectively, and RBstart represents the start RB in a UL BWP and is calculated from a frequency resource allocation method. RBoffset indicates a frequency offset between two hops through a higher layer parameter. The number of symbols of the first hop may be [NsymbPUSCH,s/2], and number of symbols of the second hop may be NsymbPUSCH,s−[NsymbPUSCH,s/2]. NsymbPUSCH,s represents the number of OFDM symbols, which corresponds to the length of PUSCH transmission in one slot.
Next, according to the inter-slot frequency hopping method supported in PUSCH repeated transmission types A and B, the UE transmits allocated resources in the frequency domain, after changing the same by a configured frequency offset, in each slot. The start RB during nsμ slots in connection with inter-slot frequency hopping may be expressed by Equation 6 below:
In Equation 6, nsμ refers to the current slot number during multi-slot PUSCH transmission, and RBstart refers to the start RB inside a UL BWP and is calculated from a frequency resource allocation method. RBoffset refers to a frequency offset between two hops through a higher layer parameter.
Next, according to the inter-repetition frequency hopping method supported in PUSCH repeated transmission type B, resources allocated in the frequency domain regarding one or multiple actual repetitions in each nominal repetition are moved by a configured frequency offset and then transmitted. The index RBstart(n) of the start RB in the frequency domain regarding one or multiple actual repetitions in the nth nominal repetition may follow Equation 7 given below:
In Equation 7, n refers to the index of nominal repetition, and RBoffset refers to an RB offset between two hops through a higher layer parameter.
In LTE and NR, a UE may perform a procedure in which, while being connected to a serving base station, the UE reports capability supported by the UE to the corresponding base station. This will be referred to as a UE capability report in the following description.
The base station may transfer a UE capability enquiry message to the UE in a connected state so as to request a capability report. The message may include a UE capability request with regard to each radio access technology (RAT) type of the base station. The RAT type-specific request may include supported frequency band combination information and the like. In addition, in the case of the UE capability enquiry message, UE capability with regard to multiple RAT types may be requested through one RRC message container transmitted by the base station, or the base station may transfer a UE capability enquiry message including multiple UE capability requests with regard to respective RAT types. That is, multiple capability enquiries may be included in one message, and may configure a UE capability information message corresponding thereto and report the same multiple times. In next-generation mobile communication systems, a UE capability request may be made regarding multi-RAT dual connectivity (MR-DC), such as NR, LTE, E-UTRA—NR dual connectivity (EN-DC). In addition, the UE capability enquiry message is transmitted initially after the UE is connected to the base station, in general, but may be requested in any condition if needed by the base station.
Upon receiving the UE capability report request from the base station in the above step, the UE configures UE capability according to band information and RAT type required by the base station. The method in which the UE configures UE capability in an NR system is summarized below:
After the UE capability is configured, the UE transfers a UE capability information message including the UE capability to the base station. The base stations performs scheduling and transmission/reception management appropriate for the UE, based on the UE capability received from the UE.
Referring to
Major functions of the NR SDAPs S25 and S70 may include some of the following functions:
With regard to the SDAP layer device, the UE may be configured, through an RRC message, whether to use the header of the SDAP layer device with regard to each PDCP layer device or with regard to each bearer or with regard to each logical channel, or whether to use functions of the SDAP layer device. If an SDAP header is configured, the NAS QOS reflection configuration 1-bit indicator (NAS reflective QoS) of the SDAP header and the AS QoS reflection configuration 1-bit indicator (AS reflective QoS) thereof may be indicated such that the UE can update or reconfigure mapping information regarding the QoS flow and data bearer of the uplink and downlink. The SDAP header may include QOS flow ID information indicating the QoS. The QoS information may be used as data processing priority for providing efficient services, scheduling information, or the like.
Major functions of the NR PDCPs S30 and S65 may include some of the following functions:
The above-mentioned reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in an order based on the PDCP sequence number (SN), and may include a function of transferring data to an upper layer in the reordered sequence. Alternatively, the reordering function of the NR PDCP device may include a function of instantly transferring data without considering the order, may include a function of recording PDCP PDUs lost as a result of reordering, may include a function of reporting the state of the lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of the lost PDCP PDUs.
Major functions of the NR RLCs S35 and S60 may include some of the following functions:
The above-mentioned in-sequence delivery function of the NR RLC device refers to a function of successively delivering RLC SDUs received from the lower layer to the upper layer. The in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering multiple RLC SDUs received, into which one original RLC SDU has been segmented, may include a function of reordering the received RLC PDUs with reference to the RLC sequence number (SN) or PDCP sequence number (SN), may include a function of recording RLC PDUs lost as a result of reordering, may include a function of reporting the state of the lost RLC PDUs to the transmitting side, and may include a function of requesting retransmission of the lost RLC PDUs. The in-sequence delivery function of the NR RLC device may include a function of, if there is a lost RLC SDU, successively delivering only RLC SDUs before the lost RLC SDU to the upper layer, and may include a function of, if a predetermined timer has expired although there is a lost RLC SDU, successively delivering all RLC SDUs received before the timer was started to the upper layer. Alternatively, the in-sequence delivery function of the NR RLC device may include a function of, if a predetermined timer has expired although there is a lost RLC SDU, successively delivering all currently received RLC SDUs to the upper layer. In addition, the RLC PDUs may be processed in the received order (regardless of the sequence number order, in the order of arrival) and delivered to the PDCP device regardless of the order (out-of-sequence delivery). In the case of segments, segments which are stored in a buffer, or which are to be received later, may be received, reconfigured into one complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may include no concatenation function, which may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.
The out-of-sequence delivery function of the NR RLC device refers to a function of instantly delivering RLC SDUs received from the lower layer to the upper layer regardless of the order, may include a function of reassembling and delivering multiple RLC SDUs received, into which one original RLC SDU has been segmented, and may include a function of storing the RLC SN or PDCP SN of received RLC PDUs, and recording RLC PDUs lost as a result of reordering.
The NR MACs S40 and S55 may be connected to multiple NR RLC layer devices configured in one UE, and major functions of the NR MACs may include some of the following functions:
The NR PHY layers S45 and S50 may perform operations of channel-coding and modulating upper layer data, thereby obtaining OFDM symbols, and delivering the same through a radio channel, or demodulating OFDM symbols received through the radio channel, channel-decoding the same, and delivering the same to the upper layer.
The detailed structure of the radio protocol structure may be variously changed according to the carrier (or cell) operating scheme. As an example, assuming 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 with regard to each layer, such as S00. On the other hand, assuming that the base station transmits data to the UE based on carrier aggregation (CA) which uses multiple carriers in a single TRP, the base station and the UE use a protocol structure which has a single structure up to the RLC, such as S10, but multiplexes the PHY layer through a MAC layer. As another example, assuming that the base station transmits data to the UE based on dual connectivity (DC) which uses multiple carriers in multiple TRPs, the base station and the UE use a protocol structure which has a single structure up to the RLC, such as S20, but multiplexes the PHY layer through a MAC layer.
Next, an uplink channel estimation method using sounding reference signal (SRS) transmission of a UE will be described. The base station may configure at least one SRS configuration with regard to each uplink BWP in order to transfer configuration information for SRS transmission to the UE, and may also configure as least one SRS resource set with regard to each SRS configuration. As an example, the base station and the UE may exchange higher layer signaling information as follows, in order to transfer information regarding the SRS resource set.
The UE may understand that an SRS resource included in a set of SRS resource indices referred to by an SRS resource set follows the information configured for the SRS resource set.
In addition, the base station and the UE may transmit/receive higher layer signaling information in order to transfer individual configuration information regarding SRS resources. As an example, the individual configuration information regarding SRS resources may include time-frequency domain mapping information inside slots of the SRS resources, and this may include information regarding intra-slot or inter-slot frequency hopping of the SRS resources. In addition, the individual configuration information regarding SRS resources may include time domain transmission configuration of SRS resources, and may be configured as one of “periodic,” “semi-persistent,” and “aperiodic.” This may be limited to have the same time domain transmission configuration as the SRS resource set including the SRS resources. If the time domain transmission configuration of SRS resources is configured as “periodic” or “semi-persistent,” the time domain transmission configuration may further include an SRS resource transmission cycle and a slot offset (for example, periodicity AndOffset).
The base station may activate or deactivate or trigger SRS transmission by the UE through higher layer signaling including RRC signaling or MAC CE signaling, or L1 signaling (for example, DCI). For example, the base station may activate or deactivate periodic SRS transmission by the UE through higher layer signaling. The base station may indicate activation of an SRS resource set having resourceType configured as “periodic” through higher layer signaling, and the UE may transmit the SRS resource referred to by the activated SRS resource set. Intra-slot time-frequency domain resource mapping of the transmitted SRS resource follows resource mapping information configured for the SRS resource, and slot mapping, including the transmission cycle and slot offset, follows periodicity AndOffset configured for the SRS resource. In addition, the spatial domain transmission filter applied to the transmitted SRS resource may refer to spatial relation info configured for the SRS resource, or may refer to associated CSI-RS configured for the SRS resource set including the SRS resource. The UE may transmit the SRS resource inside the uplink BWP activated with regard to the periodic SRS resource activated through higher layer signaling.
For example, the base station may activate or deactivate semi-persistent SRS transmission by the UE through higher layer signaling. The base station may indicate activation of an SRS resource set through MAC CE signaling, and the UE may transmit the SRS resource referred to by the activated SRS resource set. The SRS resource set activated through MAC CE signaling may be limited to an SRS resource set having resourceType configured as “semi-persistent.” Intra-slot time-frequency domain resource mapping of the transmitted SRS resource follows resource mapping information configured for the SRS resource, and slot mapping, including the transmission cycle and slot offset, follows periodicity AndOffset configured for the SRS resource. In addition, the spatial domain transmission filter applied to the transmitted SRS resource may refer to spatial relation info configured for the SRS resource, or may refer to associated CSI-RS configured for the SRS resource set including the SRS resource. If the SRS resource has spatial relation info configured therefor, the spatial domain transmission filter may be determined, without following the same, by referring to configuration information regarding spatial relation info transferred through MAC CE signaling that activates semi-persistent SRS transmission. The UE may transmit the SRS resource inside the uplink BWP activated with regard to the semi-persistent SRS resource activated through higher layer signaling.
For example, the base station may trigger aperiodic SRS transmission by the UE through DCI. The base station may indicate one of aperiodic SRS triggers (aperiodicSRS-ResourceTrigger) through the SRS request field of DCI. The UE may understand that the SRS resource set including the aperiodic SRS resource trigger indicated through DCI in the aperiodic SRS resource trigger list, among configuration information of the SRS resource set, has been triggered. The UE may transmit the SRS resource referred to by the triggered SRS resource set. Intra-slot time-frequency domain resource mapping of the transmitted SRS resource follows resource mapping information configured for the SRS resource. In addition, slot mapping of the transmitted SRS resource may be determined by the slot offset between the SRS resource and a PDCCH including DCI, and this may refer to value(s) included in the slot offset set configured for the SRS resource set. Specifically, as the slot offset between the SRS resource and the PDCCH including DCI, a value indicated in the time domain resource assignment field of DCI, among offset value(s) included in the slot offset set configured for the SRS resource set, may be applied. In addition, the spatial domain transmission filter applied to the transmitted SRS resource may refer to spatial relation info configured for the SRS resource, or may refer to associated CSI-RS configured for the SRS resource set including the SRS resource. The UE may transmit the SRS resource inside the uplink BWP activated with regard to the aperiodic SRS resource triggered through DCI.
When the base station triggers aperiodic SRS transmission by the UE through DCI, a minimum time interval may be necessary between the transmitted SRS and the PDCCH including the DCI that triggers aperiodic SRS transmission, in order for the UE to transmit the SRS by applying configuration information regarding the SRS resource. The time interval for SRS transmission by the UE may be defined as the number of symbols between the last symbol of the PDCCH including the DCI that triggers aperiodic SRS transmission and the first symbol mapped to the first transmitted SRS resource among transmitted SRS resource(s). The minimum time interval may be determined with reference to the PUSCH preparation procedure time needed by the UE to prepare PUSCH transmission. In addition, the minimum time interval may have a different value depending on the place of use of the SRS resource set including the transmitted SRS resource. For example, the minimum time interval may be determined as N2 symbols defined in view of UE processing capability that follows the UE's capability with reference to the UE's PUSCH preparation procedure time. In addition, if the place of use of the SRS resource set is configured as “codebook” or “antennaSwitching” in view of the place of use of the SRS resource set including the transmitted SRS resource, the minimum time interval may be determined as N2 symbols, and if the place of use of the SRS resource set is configured as “nonCodebook” or “beamManagement,” the minimum time interval may be determined as N2+14 symbols. The UE may transmit an aperiodic SRS if the time interval for aperiodic SRS transmission is larger than or equal to the minimum time interval, and may ignore the DCI that triggers the aperiodic SRS if the time interval for aperiodic SRS transmission is smaller than the minimum time interval.
Next, SRS parameters may be semi-statically configured by higher layer parameter SRS-Resource.
Configuration information spatialRelationInfo in [Table 29] above is applied, with reference to one reference signal, to a beam used for SRS transmission corresponding to beam information of the corresponding reference signal. For example, configuration of spatialRelationInfo may include information as in [Table 30] below:
Referring to the spatialRelationInfo configuration, an SS/PBCH block index, CSI-RS index, or SRS index may be configured as the index of a reference signal to be referred to in order to use beam information of a specific reference signal. Higher layer signaling referenceSignal corresponds to configuration information indicating which reference signal's beam information is to be referred to for corresponding SRS transmission, ssb-Index refers to the index of an SS/PBCH block, csi-RS-Index refers to the index of a CSI-RS, and srs refers to the index of an SRS. If higher layer signaling referenceSignal has a configured value of “ssb-Index,” the UE may apply the reception beam which was used to receive the SS/PBCH block corresponding to ssb-Index as the transmission beam for the corresponding SRS transmission. If higher layer signaling referenceSignal has a configured value of “csi-RS-Index,” the UE may apply the reception beam which was used to receive the CSI-RS corresponding to csi-RS-Index as the transmission beam for the corresponding SRS transmission. If higher layer signaling referenceSignal has a configured value of “srs,” the UE may apply the reception beam which was used to transmit the SRS corresponding to srs as the transmission beam for the corresponding SRS transmission.
It is to be noted that, although it has been assumed in the above description that a TCI state is used for downlink channel beam indication (UE's reception space filter value/type indication), and SpatialRelationInfo is used for uplink channel beam indication (UE's transmission space filter value/type indication), this does not mean limitations based on the up/downlink type, and can be expanded mutually in the future. For example, a conventional downlink TCI state (DL TCI state) may be expanded to an uplink TCI state (UL TCI state) through a method such as adding an uplink channel or signal to the type of target RS that can refer to the TCI state, or adding an uplink channel or signal to the type of referenceSignal (reference RS) included in the TCI state or QCL-Info. As an example, the base station may configure a higher layer signaling parameter, such as srs-TCIState-r17 in [Table 29] described, for the UE, thereby notifying of SRS transmission beam information by using a TCI state, not spatialrelationinfo. There are various other expansion methods such as DL-UL joint TCI state, but not all methods will be described not to unnecessarily obscure the gist of description.
An SRS may include a constant amplitude zero auto correlation (CAZAC) sequence. CAZAC sequences constituting respective SRSs transmitted from multiple UEs have different cyclic shift values. In addition, CAZAC sequences generated through a cyclic shift from one CAZAC sequence are characterized by having zero correlation value with sequences having different cyclic shift values from them, respectively. Such characteristics may be used to distinguish SRSs allocated in the same frequency domain simultaneously according to the CAZAC sequence cyclic shift value configured for each SRS by the base station.
SRSs of multiple UEs may be distinguished not only according to the cyclic shift value, but also according to the frequency location. The frequency location may be distinguished by SRS sub-band unit allocation or Comb. 5G or NR systems may support Comb2, Comb4, and Comb8. In the case of Comb2, one SRS may be allocated only to even-numbered or odd-numbered subcarriers in an SRS sub-band. Each of the even-numbered subcarriers and odd-numbered subcarriers may constitute one Comb.
Each UE may have an SRS sub-band allocated based on a tree structure. The UE may then perform hopping with regard to the SRS allocated to each sub-band at each SRS transmission timepoint. Accordingly, all transmission antennas of the UE may transmit SRSs by using the entire uplink data transmission bandwidth.
Assuming that the level index of the tree structure in
The tree structure having the above configuration may have various level numbers, SRS sub-band sizes, and SRS sub-band numbers per one level, according to the base station's configuration. The number of SRS sub-bands generated at level b from one SRS sub-band at the upper level may be defined as Nb, and the index of the Nb SRS sub-bands may be defined as nb={0, . . . ,Nb-1}. As sub-bands per level are varied in this manner, UEs may be allocated to respective sub-bands per level as illustrated in
Specifically, for the above-described SRS sub-band configuration, NR supports SRS bandwidth configurations as in [Table 31] below:
In addition, NR supports SRS frequency hopping based on values in Table 31 above, and detailed procedures follow Table 32 below:
TC ∈ {0,1, . . . , KTC−1} is contained in the higher-layer parameter
As described above, 5G or NR UEs support a single user (SU)-MIMO technique and have a maximum of four transmission antennas. In addition, NR UEs may simultaneously transmit multiple SRSs through multiple CCs or multiple SRS sub-bands inside multiple CCs. 5G or NR systems support various numerologies, unlike LTE systems, may have multiple SRS transmission symbols configured variously, and may be allowed to repeatedly transmit SRSs through a repetition factor.
Therefore, it is necessary to count SRS transmissions in view thereof. Counting SRS transmissions may be variously utilized. For example, counting SRS transmissions may be utilized to support antenna switching resulting from SRS transmissions. Specifically, it may be determined by SRS transmission counting at what SRS transmission timepoint, an SRS corresponding to what antenna is to be transmitted in what band.
The UE does not expect different time domain operations to be configured with regard to SRS resources in the same SRS resource set. In addition, the UE does not expect different time domain operations to be configured with regard to the SRS resource set associated with SRS resources. An SRS request area included in DCI formats 0_1, 1_1, 0_2 (when the SRS request area exists), and 1_2 (when the SRS request area exists), indicates a triggered SRS resource set as in [Table 33] below. If higher layer parameter srs-TPC-PDCCH-Group regarding the UE is configured as “typeB,” the 2-bit SRS request area included in DCI format 2_3 indicates a triggered SRS resource set. Alternatively, if higher layer parameter srs-TPC-PDCCH-Group regarding the UE is configured as “typeA,” the 2-bit SRS request area included in DCI format 2_3 indicates SRS transmission regarding a set of resource cells configured by the higher layer.
With regard to a PUCCH and an SRS scheduled with the same carrier, if a semi-persistent SRS and a periodic SRS are configured in the same symbol as the PUCCH including only CSI report, or including only L1-RSRP report, or including only L1-SINR report, the UE does not transmit the SRS. If a semi-persistent SRS or a periodic SRS is configured in the same symbol as a PUCCH including a HARQ-ACK, a link restoration request, and/or an SR, or if an aperiodic SRS is triggered to be transmitted in the same symbol as a PUCCH including the above information, the UE transmits no SRS. If no SRS is transmitted while overlapping a PUCCH, only SRS symbol(s) overlapping the PUCCH are dropped. If an aperiodic SRS is triggered to overlap the same symbol as a PUCCH including a semi-persistent/periodic CSI report, or a semi-persistent/periodic L1-RSRP report only, or an L1-SINR report only, no PUCCH is transmitted.
In the case of a band-band combination which does not allow simultaneous transmission of an SRS and a PUCCH/PUSCH with regard to intra-band carrier aggregation or inter-band carrier aggregation, the UE does not expect PUSCH/UL DM-RS/UL PT-RS/PUCCH formats to be configured from a carrier different from the carrier having an SRS configured in the same symbol.
In the case of a band-band combination which does not allow simultaneous transmission of an SRS and a PRACH with regard to intra-band carrier aggregation or inter-band carrier aggregation, the UE does not simultaneously transmit the SRS from one carrier and the PRACH from another carrier.
If an SRS resource having higher layer parameter resourceType configured as “aperiodic” is triggered by OFDM symbol(s) for periodic/semi-persistent SRS, the UE transmits an aperiodic SRS resource, periodic/semi-persistent SRS symbol(s) overlapping the corresponding symbol(s) are dropped, and non-overlapping periodic/semi-persistent SRS symbol(s) are transmitted. If an SRS resource having higher layer parameter resourceType configured as “semi-persistent”is triggered by OFDM symbol(s) for periodic SRS transmission, the UE transmits a semi-persistent SRS resource, periodic SRS symbol(s) are dropped during overlapping symbols, and non-overlapping periodic SRS symbol(s) are transmitted.
If higher layer parameter “usage” inside SRS-ResourceSet is configured as “antennaSwitching,” and if a guard period corresponding to Y symbols is configured, the UE follows the same priority rule as defined above like an SRS is configured even during the guard period.
When higher layer parameter spatialRelationInfo of a semi-persistent or aperiodic SRS resource is activated or updated by a MAC CE with regard to a CC/bandwidth part indicated by a set of higher layer parameters applicableCellList, spatialRelationInfo is applied to semi-persistent or aperiodic SRS resource(s) having the same SRS resource ID with regard to all bandwidth parts inside indicated CCs.
If higher layer parameter enableDefaultBeamPlForSRS is configured as “enable,” if higher layer parameter spatialRelationInfo for SRS resources is not configured in FR2, except for a case in which higher layer parameter “usage” of SRS resources is configured as “beamManagement” or configured as “nonCodebook” together with associatedCSI-RS configuration, and if higher layer parameter pathlossReferenceRS regarding the UE is not configured, the UE transmits a target SRS resource according to the following configurations:
Table 34 describes UE capability containing resource-related information of positioning uplink reference signals.
After reporting the UD capability in Table 34 above (hereinafter, referred to as FG 13-8), the UE may transmit an uplink reference signals at all OFDM symbol locations inside a specific slot during uplink reference signal transmission.
Table 35 describes UE capability containing information of intra-slot transmission symbol locations of an uplink reference signal in an unlicensed band.
After reporting the UE capability in Table 35 above (hereinafter, referred to as FG 10-11), the UE may transmit an uplink reference signals at all OFDM symbol locations inside any slot in both a licensed band and an unlicensed band during uplink reference signal transmission.
Hereinafter, an SRS for antenna switching will be described.
An SRS transmitted from a UE may be used by a base station to acquire DL channel state information (CSI) (for example, DL CSI acquisition). As a specific example, in a single-cell or multi-cell (for example, carrier aggregation (CA)) situation based on time division duplex (TDD), a base station (BS) may schedule transmission of an SRS to user equipment (UE) and then measure the SRS transmitted from the UE. In this case, by assuming reciprocity between the downlink (DL) and the uplink (UL) channels, the base station may consider that uplink channel information estimated based on the SRS transmitted from the UE is downlink channel information, and may perform scheduling of downlink signal/channel for the UE by using this. The usage of the SRS for downlink channel information acquisition may be configured for the UE as antenna switching by the base station.
As an example, according to specifications (for example, 3gpp TS38.214), the usage of an SRS may be configured for the base station and/or UE by using a higher layer parameter (for example, usage of RRC parameter SRS-ResourceSet). The usage of an SRS may be configured as beam management usage, codebook transmission usage, non-codebook transmission usage, antenna switching usage, and the like.
As described, if parameter “usage” inside higher layer signaling SRS-ResourceSet is configured by the base station as “antennaSwitcing” for the UE, the UE may receive at least one higher layer signaling configuration from the base station according to reported UE capability. The UE may report “supportedSRS-TxPortSwitch” as UE capability, and its value may be as follows. In the following, “mTnR” may mean UE capability supporting transmission through m antennas and reception through n antennas.
Regarding the UE's 1T2R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereon may be possible.
Regarding the UE's 2T4R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
Regarding the UE's 1T4R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
The base station may configure, for the UE, a maximum of one (that is, 0 or 1) SRS resource set having resourceType value of “periodic” or “semi-persistent” in SRS-ResourceSet which is higher layer signaling.
The base station may configure, for the UE, 0 or 2 SRS resource sets having resource Type value of “aperiodic” in SRS-ResourceSet which is higher layer signaling. If two SRS resource sets are configured, some or all of the following details may be considered.
The UE may expect that the base station may configure the same values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that can be configured in each SRS resource set through higher layer signaling, in all SRS resource sets, respectively. That is, the UE may expect that multiple SRS resource sets may all have the same power control parameters. Such a restriction may be hereinafter referred to as a [power control parameter restriction].
Regarding the UE's 1T1R, 2T2R, and 4T4R operations, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
Regarding the UE's 1T6R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
If the UE did not report srs-AntennaSwitching2SP-1Periodic-r17 which is a UE capability report, the base station may configure, for the UE, a maximum of one (that is, 0 or 1) SRS resource set having resourceType value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling.
If the UE reported srs-AntennaSwitching2SP-1Periodic-r17 which is a UE capability report, the base station may configure, for the UE, a maximum of two (that is, 0, 1, or 2) SRS resources set having resource Type value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling, and two SRS resource sets having resourceType value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling may not be activated simultaneously.
One SRS resource set may include six SRS resources, each SRS resource may include one SRS port, respective SRS resources may be transmitted at different OFDM symbol locations in identical or different slots, and the one SRS port of respective SRS resources may be connected to different UE antenna ports.
If three SRS resource sets are configured, a total of six SRS resources may be divided and included in the three SRS resource sets, each SRS resource may include one SRS port, all SRS resources in each SRS resource set may be transmitted at different OFDM symbol locations in the same slot, SRS transmission regarding different SRS resource sets may be performed in identical or different OFDM symbol locations of different slots, and the one SRS port of respective SRS resources may be connected to different UE antenna ports.
Regarding the UE's 1T8R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
If the UE did not report srs-AntennaSwitching2SP-1Periodic-r17 which is a UE capability report, the base station may configure, for the UE, a maximum of one (that is, 0 or 1) SRS resource set having resourceType value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling.
If the UE reported srs-AntennaSwitching2SP-1Periodic-r17 which is a UE capability report, the base station may configure, for the UE, a maximum of two (that is, 0, 1, or 2) SRS resource sets having resourceType value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling, and two SRS resource sets having resourceType value of “semi-persistent” in SRS-ResourceSet which is higher layer signaling may not be activated simultaneously.
Regarding the UE's 2T6R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
Regarding the UE's 2T8R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
If three SRS resource sets are configured, a total of four SRS resources may be divided and included in the three SRS resource sets, each SRS resource may include two SRS ports, all SRS resources in each SRS resource set may be transmitted at different OFDM symbol locations in the same slot, SRS transmission regarding different SRS resource sets may be performed in identical or different OFDM symbol locations of different slots, and the two SRS ports of respective SRS resources may be connected to different UE antenna ports.
Regarding the UE's 4T8R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured, and an operation based thereof may be possible.
When the UE performs an antenna switching operation, that is, when the UE transmits different SRS resources connected to different antenna port(s), a time interval of about 15 us may be generally necessary between two adjacent SRS resources among all transmitted SRS resources. In view of this, a (minimum) guard period may be defined as in [Table 36] below:
In [Table 36], u refers to numerology, Δf refers to a subcarrier spacing, and Y may refer to the number of OFDM symbols expressing the guard period, that is, the time length of the guard period. Referring to [Table 36], the guard period may be configured based on parameter u that determines the numerology. The UE is configured not to transmit any different signal in the guard period, and the guard period may be configured to be fully used for antenna switching.
As an example, the guard period may be configured between transmission timepoints of two adjacent SRS resources in view of SRS resources transmitted at different OFDM symbol locations in the same slot.
As another example, if the UE had two SRS resource sets configured for antenna switching usage, if the two SRS resource sets were configured or triggered to be transmitted in two consecutive slots, and if the UE reported a UE capability indicating that the UE can transmit SRSs at all OFDM symbol locations inside slots, the UE may expect that there may be a guard period for antenna switching corresponding to at least Y OFDM symbols, based on [Table 36] above, between the last OFDM symbol in which SRS transmission is performed in the first slot in which SRS transmission regarding the first SRS resource set is performed, and the first OFDM symbol in which SRS transmission is performed in the second slot in which SRS transmission regarding the second SRS resource set is performed. That is, the time difference between two SRS transmissions may be actually larger than or equal to the Y OFDM symbols.
With regard to all antenna switching schemes described above, the UE may expect that the same number of SRS ports may be configured for all SRS resources in all SRS resource sets having higher layer signaling “usage” in SRS resource sets configured as “antennaSwitching” by the base station.
With regard to antenna switching schemes based on 1T24, 1T4R, 2T4R, 1T6R, 1T8R, 2T6R, 2T8R, and 4T8R operations described above, the UE may not expect that two or more among SRS resource sets having higher layer signaling “usage” configured as “antennaSwitching” by the base station may be configured or triggered in the same slot.
With regard to antenna switching schemes based on 1T1R, 2T2R, and 4T4R operations, the UE may not expect that two or more among SRS resource sets having higher layer signaling “usage” configured as “antennaSwitching” by the base station may be configured or triggered in the same OFDM symbol.
SRS resource #0 2011 and SRS resource #1 2012 included in SRS resource set #0 2010 are transmitted at different OFDM symbol locations in slot #1, and Y OFDM symbols may exist as a guard period between SRS resource #0 and #1 (2013). In addition, during transmission regarding SRS resource #0 (2030), the UE may connect one SRS port to the first reception antenna port 2035 of the UE so as to perform SRS transmission, and during transmission regarding SRS resource #1 (2040), the UE may connect one SRS antenna port to the second reception antenna port 2045 of the UE so as to perform SRS transmission.
SRS resource #2 2021 and SRS resource #3 2022 included in SRS resource set #1 2020 are transmitted at different OFDM symbol locations in slot #1, and Y OFDM symbols may exist as a guard period between SRS resource #2 and #3 (2023). In addition, during transmission regarding SRS resource #2 (2050), the UE may connect one SRS port to the third reception antenna port 2055 of the UE so as to perform SRS transmission, and during transmission regarding SRS resource #3 (2060), the UE may connect one SRS antenna port to the fourth reception antenna port 2065 of the UE so as to perform SRS transmission.
By connecting the four SRS resources #0 to #3 described above to different reception antenna ports of the UE and then transmitting SRSs, the UE may transmit SRSs from all different reception antenna ports to be able to acquire information regarding channels connected to all reception antennas of the UE, and the base station may thereby acquire information regarding channels between the base station and the UE and utilize the same for uplink or downlink scheduling.
Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. The content in the disclosure is applicable in FDD and TDD systems. As used herein, higher layer signaling (or higher layer signaling) is a method for transferring signals from a base station to a UE by using a downlink data channel of a physical layer, or from the UE to the base station by 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, the UE may use various methods to determine whether or not to apply cooperative communication, for example, PDCCH(s) that allocates a PDSCH to which cooperative communication is applied have a specific format, or PDCCH(s) that allocates a PDSCH to which cooperative communication is applied include a specific indicator indicating whether or not to apply cooperative communication, or PDCCH(s) that allocates a PDSCH to which cooperative communication is applied are scrambled by a specific RNTI, or cooperative communication application is assumed in a specific range indicated by a higher layer. Hereinafter, it will be assumed, for convenience of description, that NC-JT case refers to a case in which the UE receives a PDSCH to which cooperative communication is applied, based on conditions similar to those described above.
Hereinafter, the description that priority between A and B is determined may be variously mentioned, such as the entity having a high priority is selected according to a predetermined priority rule, and a corresponding operation is performed, or operations regarding the entity having a lower priority is omitted or dropped.
Hereinafter, the above examples may be described through multiple embodiments, but they are not independent of each other, and one or more embodiments may be applied simultaneously or in combination.
Hereinafter, for convenience of description, a cell, a transmission point, a panel, a beam, and/or a transmission direction which can be distinguished through a higher layer/L1 parameter such as a TCI state or spatial relation information, a cell ID, a TRP ID, or a panel ID may be described as a transmission reception point (TRP), a beam, or a TCI state as a whole. Therefore, during actual application, a TRP, a beam, or a TCI state may be appropriately replaced with one of the above terms.
Hereinafter, in the disclosure, the UE may use various methods to determine whether or not to apply cooperative communication, for example, PDCCH(s) that allocates a PDSCH to which cooperative communication is applied have a specific format, or PDCCH(s) that allocates a PDSCH to which cooperative communication is applied include a specific indicator indicating whether or not to apply cooperative communication, or PDCCH(s) that allocates a PDSCH to which cooperative communication is applied are scrambled by a specific RNTI, or cooperative communication application is assumed in a specific range indicated by a higher layer. Hereinafter, it will be assumed, for convenience of description, that NC-JT case refers to a case in which the UE receives a PDSCH to which cooperative communication is applied, based on conditions similar to those described above.
Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. Hereinafter, a base station refers to an entity that allocates resources to a terminal, 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. A terminal may include 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, although embodiments of the disclosure will be described with reference to a 5G system as an example, embodiments of the disclosure are also applicable to other communication systems having similar technical backgrounds or channel types. For example, LTE or LTE-A mobile communications and mobile communication technologies developed after 5G may be included therein. Therefore, embodiments of the disclosure are also applicable to other communication systems through a partial modification without substantially deviating from the scope of the disclosure as deemed by those skilled in the art. The content in the disclosure is applicable in FDD and TDD systems.
In addition, in the following description of the disclosure, detailed descriptions of related functions or configurations will be omitted if deemed to unnecessarily obscure the gist of the disclosure. The terminology used herein is defined in view of functions in the disclosure, and may be varied depending on the intent of the user/operator, practices, and the like. Therefore, the definition thereof is to be made based on the overall context of the disclosure.
In the following description of the disclosure, higher layer signaling may refer to signaling corresponding to at least one among the following signaling, or a combination of one or more thereof:
Hereinafter, the description that priority between A and B is determined may be variously mentioned, such as the entity having a high priority is selected according to a predetermined priority rule, and a corresponding operation is performed, or operations regarding the entity having a lower priority is omitted or dropped.
As used herein, the term “slot” may generally refer to a specific time unit corresponding to a transmit time interval (TTI), may specifically refer to a slot used in a 5G NR system, or may refer to a slot or a subframe used in a 4G LTE system.
Hereinafter, the above examples may be described through multiple embodiments, but they are not independent of each other, and one or more embodiments may be applied simultaneously or in combination.
Hereinafter, a/b/c may be understood as at least one of a, b, or c.
As an embodiment of the disclosure, SRS resource configuration and indication methods will be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE. A conventional SRS resource supports a maximum of four antenna ports (hereinafter, used interchangeably with ports) as described above, and with regard to the location of all SRS resource transmission symbols determined based on higher layer signaling, the UE may perform SRS transmission through all ports in respective symbols. As an example, if the UE had a 4-port SRS resource, the number of transmission symbols of which is 4, configured by the base station through higher layer signaling, the UE could perform transmission through four ports in respective symbols.
It is expected that improved releases of NR in the future may consider a maximum of eight UE antenna ports, thereby supporting improved specifications. Corresponding functions are under discussion in the current NR release 18. There may be a possibility that in future releases or in 6th generation mobile communication systems, the UE may consider more than eight antenna ports. However, if SRSs are transmitted in all ports configured with regard to respective symbols in which SRSs are transmitted, as currently supported, and if the port number increases, transmission power for each port decreases during SRS transmission, and the base station's reception performance may be limited in the case of a UE which is at a cell boundary and thus has insufficient coverage. Therefore, the base station and the UE may consider various methods as follows such that the UE can transmit SRSs with N (a specific number larger than 4) antenna ports. Hereinafter, SRS resource transmission may be understood as transmission of an SRS based on an SRS resource. In addition, SRS resource set transmission may be understood as transmission of an SRS based on an SRS resource set. In addition, transmission of an SRS antenna port may be understood as transmission of SRSs having features of respective antenna ports.
In order to transmit an SRS having N antenna ports, the UE may have a single SRS resource configured by the base station. The base station may configure, for the UE, a single SRS resource having N antenna ports, and during SRS transmission in a single or multiple symbols of the corresponding SRS resource through the N antenna ports, the N antenna ports may be all transmitted in respective symbols. As an example, when transmitting an SRS resource of N antenna ports, the number Ns of SRS symbols of which is 4, the UE may transmit the SRS resource all through the N antenna ports in respective symbols.
Since current specification support regarding 1, 2, or 4 antenna ports is all based on a single SRS resource, and the same definition of various parameters regarding time and frequency resource allocation in [Table 29] above can be used in method 1-1. Therefore, method 1-1 may be a natural expansion in response to the increasing number of UE antenna ports. However, there may be a problem in that, based on method 1-1, the UE transmits all antenna ports in one symbol, thereby decreasing transmission power with regard to each antenna port in one symbol.
In order to transmit an SRS having N antenna ports, the UE may have a single SRS resource configured by the base station. The base station may configure, for the UE, a single SRS resource having N antenna ports, and during SRS transmission in one or more symbols configured in the corresponding SRS resource, the number of antenna ports used for transmission in respective symbols may be smaller than or equal to N, and the number of symbols necessary to transmit an SRS resource all through N antenna ports may be larger than or equal to 1.
In method 1-2, the SRS resource is transmitted through some antenna ports among the total of N antenna ports in each symbol, and the transmission power of antenna ports with regard to each symbol may be increased compared with method 1-1 in which all of the N antenna ports for each symbol are used for transmission. However, transmission through antenna ports in method 1-2 is different from the definition of conventional specifications according to which SRSs are transmitted in respective symbols through all antenna ports configured in a specific SRS resource, and the definition of various parameters regarding time and frequency resource allocation in [Table 29] above may need to be partially changed or newly defined.
In order to transmit an SRS having N antenna ports, the UE may have multiple SRS resources configured by the base station. The base station may configure, for the UE, M (M>1) SRS resources having antenna ports, the number of which is smaller than or equal to N, in order to support SRS transmission corresponding to N antenna ports from the UE. During SRS transmission in a single or multiple symbols of the corresponding SRS resource through antenna ports, the number of which is smaller than or equal to N, configured in respective SRS resources, two SRS resources may all be transmitted in respective symbols.
As an example, if two SRS resources having four antenna ports for each SRS resource are configured for the UE for SRS transmission of eight antenna ports, and if Ns is configured as 4 for the two SRS resources, the two SRS resources may all be transmitted through four antenna ports in each symbol with regard to the two SRS resources. Multiple SRS resources may be included in the same SRS resource set, or included in different SRS resource sets, respectively. Multiple SRS resources configured for SRS transmission of N (>4) antenna ports as described above may be referred to as an SRS resource group. The number N of antenna ports which may be expressed by multiple SRS resources may be larger than 4, may be 6, 8, 12, or 16, for example, and this may be expressed by SRS resources having 1, 2, or 4 antenna ports. The UE may expect that SRS resources configured by the base station or included in each SRS resource group which may be determined by the above-described rule may all have the same number of antenna ports (as in the above example, each SRS resource may have four antenna ports). In addition, case in which they have different numbers of antenna ports may not be excluded. As an example, if three SRS resources are configured to express N-8 antenna ports, the first and second SRS resources may have two antenna ports, and the third SRS resource may have four antenna ports.
Method 1-3 enables transmission of multiple SRS resources through N antenna ports unlike methods based on one SRS resource supported by current specifications, and the definition of various parameters regarding time and frequency resource allocation in [Table 29] above may need to be partially changed or newly defined. However, similarly to method 1-2, the number of antenna ports used to transmit respective SRS resource with regard to respective symbols is smaller than or equal to the entire number N of antenna ports, and the transmission power may increase with regard to each port.
[Method 1-4] Method for Selecting from Above-Described [Method 1-1] to [Method 1-3]
In order to transmit an SRS having N antenna ports, the UE may be instructed semi-statically or dynamically by the base station to use one of the above-described [Method 1-1] to [Method 1-3]. As an example, the UE may use one of the above-described [Method 1-1] to [Method 1-3] according to a configuration instruction received from the base station through higher layer signaling, or may dynamically receive an instruction through L1 signaling. Alternatively, the UE may use one of two methods, such as one of [Method 1-1] and [Method 1-2], one of [Method 1-1] and [Method 1-3], or one of [Method 1-2] and [Method 1-3], according to a configuration instruction received from the base station through higher layer signaling, or may dynamically receive an instruction through L1 signaling. If the UE is positioned inside a cell and thus has sufficient coverage, the base station may configure SRS transmission regarding N antenna ports based on [Method 1-1] for the UE through higher layer signaling, or may dynamically instruct the same through L1 signaling. As a method for dynamically instructing the same through L1 signaling, a new field inside a DCI format, for example, may be used, or a reserved code point of a currently existing DCI field may be used, and an SRS request field may be used, for example.
The UE may report UE capability to the base station regarding whether a combination of at least one of the above-described [Method 1-1] to [Method 1-4] can be supported. The UE capability may be reported differently depending on the frequency range (FR), or may be reported with regard to each band, each band combination, each feature set, or each feature set per CC. In addition, the above-mentioned UE capability may be UE capabilities independent of each other, or multiple components inside a single UE capability may be used to define whether respective methods are supported.
If the UE supports a combination of at least one of the above-described [Method 1-1] to [Method 1-4], higher layer signaling “usage” of an SRS resource set may be capable of codebook and antenna switching. In addition, a case in which the usage is non-codebook and beam management may not be excluded.
If the above-described [Method 1-3] is followed, and if the UE has multiple SRS resources configured in the same SRS resource set, the maximum number of SRS resources in the corresponding SRS resource set which may be configured for the UE through higher layer signaling may be 4 or larger. If the UE has multiple SRS resources configured in different SRS resource sets, the UE may have two or more SRS resource sets, the usage of which is codebook, through higher layer signaling.
If the above-described [Method 1-3] is followed, the UE uses multiple SRS resources having N antenna ports for SRS transmission, and the UE may thus need to change the definition regarding a codepoint inside an SRS resource indicator (SRI) inside DCI format 0_1, 0 2 transmitted from the base station for the purpose of scheduling regarding codebook-based PUSCH transmission. Each codepoint in the current SRIs indicates a single SRS resource, but if the UE is configured by the base station so as to use the above-described [Method 1-3], the definition regarding the codepoint of the SRI field may be changed according to the following methods:
The UE may assume that each codepoint of the SRI field in DCI format 0_1 and 0_2 indicated by the base station indicates an SRS resource group including multiple SRS resources. As an example, if the SRI has two codepoints, the first codepoint may indicate SRS resource group 0, and the second codepoint may indicate SRS resource group 1. SRS resource group 0 may include SRS resources 0 and 1, and SRS resource group 1 may include SRS resources 2 and 3. The base station may configure such SRS resource groups for the UE by a higher layer. In addition, if the base station configures multiple SRS resources in the same SRS resource group, the UE may determine that a specific number of SRS resources from the lowest SRS resource index in the corresponding SRS resource set constitutes one group.
The total number of antenna ports expressed through multiple SRS resources may be configured for each SRS resource set. As an example, if the number of antenna ports configured in an SRS resource set is 8, if the total number of SRS resources is 4, and if the index of respective SRS resources is 0 to 3, SRS resource indices 0 and 1 may constitute the first SRS resource group, and SRS resource indices 2 and 3 may constitute the second SRS resource group. In this case, the first SRS resource group may correspond to the first codepoint of the SRI field, and the second SRS resource group may correspond to the second codepoint.
The UE may assume that each codepoint of the SRI field in DCI format 0 1 and 0_2 indicated by the base station indicates a single SRS resource or a combination of multiple SRS resources. This may be similar to the meaning of the SRI field in DCI format 0_1 and 0 2 for scheduling non-codebook-based PUSCH transmission. If four SRS resources are configured in an SRS resource set having usage configured as non-codebook, a total of 24−1=15 codepoints may be needed by each SRI field in DCI format 0_1 and 0_2 for scheduling non-codebook-based PUSCH transmission, in order to express all methods for selecting one to four from the four SRS resources. Similarly to a non-codebook scheme that considers all methods for selecting subsets from all configured SRS resources in this manner, method 1-3-2 may use a method of selecting all or some of subsets.
As an example, assuming that the total number of SRS resources is M, and assuming that M SRS resources all have the same number of antenna ports, combinations of only a specific number of SRS resources among the M SRS resources may be considered. As an example, a method for selecting two from M may be considered. In this case, the SRI field may have as many codepoints as the methods for selecting two from M. If it is assumed that the M SRS resources may have different numbers of antenna ports, a case in which respective combinations of SRS resources have the same total number of antenna ports may be generated by considering the combination of a specific number of SRS resources or another specific number of SRS resources among M. The SRI field may have a codepoint which may indicate the number of respective combinations of SRS resources. As an example, if one SRS resource set includes four SRS resources each having two antenna ports and two SRS resources each having four antenna ports, and if a total of eight antenna ports are to be expressed by using multiple SRS resources, a combination of two SRS resources each having four antenna ports may be used, or a combination of one SRS resource having four antenna ports and two SRS resources each having two antenna ports may be used.
The UE may assume that each codepoint of the SRI field in DCI format 0 1 and 0_2 indicated by the base station indicates a single SRS resource, and the single SRS resource indicated by each codepoint may be connected to multiple other SRS resources. The total number of SRS ports configured for multiple other SRS resources connected to the single SRS resource may be N. The corresponding connection may be configured through higher layer signaling. The base station and the UE may not change the definition of each codepoint of the SRI field, and the base station may indicate one SRS resource to the UE and may simultaneously indicate multiple SRS resources connected thereto through higher layer signaling as well.
The UE may report UE capability to the base station regarding whether a combination of at least one of the above-described [Method 1-3-1] to [Method 1-3-3] can be supported. The UE capability may be reported differently depending on the frequency range (FR), or may be reported with regard to each band, each band combination, each feature set, or each feature set per CC. In addition, the above-mentioned UE capability may be UE capabilities independent of each other, or multiple components inside a single UE capability may be used to define whether respective methods are supported.
With regard to above-described [Method 1-3], if the UE receives higher layer signaling from the base station with regard to multiple SRS resources in order to use above-described [Method 1-3-1] to [Method 1-3-3], the UE may distinguish, among various pieces of higher layer signaling configuration information inside SRS resources mentioned in [Table 29] above from the base station, pieces of higher layer signaling configuration information which need to be configured identically with regard to all of multiple SRS resources necessary to transmit an SRS having N antenna ports from pieces of information which may be identical or different between respective SRS resources.
The UE may expect that, among parameters in [Table 29], parameters related to the SRS transmission sequence, such as groupOrSequenceHopping and sequenceld, and a parameter indicating periodic, semi-static, or aperiodic transmission of SRS resources, such as resource Type, may be configured identically with regard to all of multiple SRS resources necessary to transmit an SRS having N antenna ports.
In addition, the UE may expect that, among parameters in [Table 29], resourceMapping, resourceMapping-r16, and resourceMapping-17 (information related to SRS time resource allocation), and freqDomainPosition, freqDomainShift, and freqHopping (information related to frequency resource allocation) may be configured identically or differently with regard to multiple SRS resources necessary to transmit an SRS having N antenna ports. In addition, the UE may expect that transmissionComb and transmissionComb-n8-r17, which determine the frequency and location of a transmission RE of an SRS, may have the same comb value with regard to multiple SRS resources, and may expect that the comb offset may be configured identically or differently. In addition, the UE may expect that the partial factor, which is configured for an RB level partial frequency sounding operation of an SRS, may also have the same value with regard to multiple SRS resources.
The UE may expect that, among parameters in [Table 29], information for determining the transmission beam of an SRS, such as spatialrelationinfo and srs-TCIState-r17, may be configured identically or differently with regard to multiple SRS resources. Particularly, if multiple SRS resources are configured in different SRS resource sets, the UE may expect that the two parameters related to transmission beam determination may be configured differently with regard to multiple SRS resources.
As an embodiment of the disclosure, SRS time resource allocation, repeated transmission, and frequency hopping methods according to the SRS resource configuration and indication methods described above in the above embodiment will be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE.
According to [Table 29] above, the UE may determine the time domain transmission resource location during frequency hopping of an SRS resource through higher layer signaling such as startPosition which refers to a transmission start symbol in a slot of an SRS resource, nrofSymbols which refers to the number of consecutively transmitted symbols from the transmission start symbol in a slot, and repetitionFactor which refers to the number of consecutive symbols having frequency resources at the same location during frequency hopping.
If [method 1-1] in the above embodiment is used, that is, N antenna ports are all configured for one SRS resource, and if the SRS resource is transmitted by using all of N antenna ports with regard to each transmission symbol, the UE may perform the following operations or operations according to a combination of some thereof according to a combination of startPosition, nrofSymbols, and repetitionFactor, which are higher layer signaling, with regard to periodic/semi-persistent/aperiodic SRS transmission.
If [method 1-2] in the above embodiment is used, that is, if N antenna ports are configured for one SRS resource, and if some of the N antenna ports are transmitted with regard to each transmission symbol, the UE may perform the following operations by considering the definition of startPosition, nrofSymbols, and repetitionFactor which are higher layer signaling.
[Time resource operation 2-1]
The UE may consider that Ns has the existing definition, that is, refers to the number of consecutive symbols in which the corresponding SRS resource is transmitted. If N antenna ports are configured for one SRS resource, and if the SRS resource is transmitted through some of the N antenna ports with regard to each transmission symbol, the UE may expect, based on an assumption that M symbols are necessary to transmit the SRS resource through all of the N antenna ports, that Ns having M as its divisor may be configured for the corresponding SRS resource.
As an example, assuming that N=8 antenna ports are configured for the UE, that an SRS resource is transmitted through four antenna ports with regard to each transmission symbol, and the SRS resource is transmitted through all of N=8 antenna ports through M=2 symbols, the UE may have one of Ns=2, 4, 8, 10, 12, and 14, which are multiples of M=2, configured with regard to the corresponding SRS resource. If Ns is 4, the number of consecutive symbols through which the corresponding SRS resource is transmitted is 4, and it may be expected that the SRS resource may be transmitted in the first and third symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the SRS resource may be transmitted in the second and fourth symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). As another method, it may be expected that the SRS resource may be transmitted in the first two symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the SRS resource may be transmitted in the remaining two symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). (The disclosure may not be limited to the above-described examples, and another example in which 4 among the total of 8 antenna ports are configured such as SRS antenna ports 0, 2, 4, 6 may not be excluded.)
The UE may consider that R has the existing definition, that is, refers to the number of consecutive symbols having frequency resources at the same location, in which the corresponding SRS resource is transmitted. Therefore, as described above, the value of R that may be configured for the UE may be a divisor of Ns. If the UE has N antenna ports configured for one SRS resource, if the SRS resource is transmitted through some of the N antenna ports with regard to each transmission symbol, and if M symbols are necessary to transmit the SRS resource through all of the N antenna ports, the minimum value of R may be 1 or M.
Based on time resource operation 2-1 above, the UE may perform the following operations or operations according to a combination of some thereof according to a combination of startPosition, nrofSymbols, and repetitionFactor, which are higher layer signaling, with regard to periodic/semi-persistent/aperiodic SRS transmission.
Assuming that the number of symbols necessary to transmit all antenna ports of a corresponding SRS resource is defined as M, the UE may understand that Ns is defined as a value indicating how many times the M symbols are used to transmit the corresponding SRS resource. That is, Ns may be defined as information regarding how many times M symbols units are used consecutively to transmit all of N antenna ports configured in an SRS resource, unlike the existing definition (the number of consecutive symbols used to transmit the SRS resource). As an example, assuming that N=8 antenna ports are configured for the UE, that an SRS resource is transmitted through four antenna ports with regard to each transmission symbol, and that the SRS resource is transmitted through all of N=8 antenna ports through M=2 symbols, the UE may have one of Ns=1, 2, 4, 5, 6, and 7 configured as information regarding how many times M=2 symbol units are used consecutively with regard to the corresponding SRS resource. As an example, if Ns is 2, the total number of consecutive symbols through which the corresponding SRS resource is transmitted may be 4, and this may mean that M=2 symbol units were used twice consecutively.
In addition, it may be expected that the SRS resource may be transmitted in the first and third symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the SRS resource may be transmitted in the second and fourth symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). As another method, it may be expected that the SRS resource may be transmitted in the first two symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the SRS resource may be transmitted in the remaining two symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). (The disclosure may not be limited to the above-described examples, and another example in which 4 among the total of 8 antenna ports are configured such as SRS antenna ports 0, 2, 4, 6 may not be excluded.)
The UE may assume that R has the existing definition, that is, refers to the number of consecutive symbols having frequency resources at the same location, in which the corresponding SRS resource is transmitted. Therefore, as described above, the value of R that may be configured for the UE may be a divisor of Ns. If the UE has N antenna ports configured for one SRS resource, if some of the N antenna ports are transmitted with regard to each transmission symbol, and if M symbols are necessary to transmit all of the N antenna ports, the minimum value of R may be 1 or M.
Based on time resource operation 2-2 above, the UE may perform the following operations or operations according to a combination of some thereof according to a combination of startPosition, nrofSymbols, and repetitionFactor, which are higher layer signaling, with regard to periodic/semi-persistent/aperiodic SRS transmission.
If [method 1-3] in the above embodiment is used, that is, if N antenna ports are configured throughout all of multiple SRS resources, and if some of the N antenna ports configured with regard to each SRS resource and then transmitted, the UE may perform the following operations by considering the definition of startPosition, nrofSymbols, and repetitionFactor which are higher layer signaling.
The UE may configure the total number of symbols in which multiple SRS resources are transmitted to be Ns of respective SRS resources. Assuming that each of n SRS resources are transmitted in m symbols, Ns may be n*m, and may Ns be configured as the same value in respective SRS resources. Assuming that the UE has N antenna ports configured with regard to each of multiple SRS resources, or N/n antenna ports configured with regard thereto (n may be a divisor of N), that some of the N antenna ports are transmitted with regard to each SRS resource, and that M (M may be smaller than or equal to m) symbols are necessary with regard to each SRS resource to transmit N antenna ports all (that is, a total of n*M OFDM symbols are necessary to transmit N antenna ports), the UE may then expect that Ns, which has n, m, and M as its divisors, may be configured with regard to each SRS resource.
As an example, assuming that two SRS resources that may express N=8 antenna ports are configured for the UE, and each SRS resource is transmitted in m=2 symbols, the UE may then have one of Ns=2, 4, 8, 10, 12, and 14, which have m=2 as divisors, configured with regard to each of the multiple SRS resources. If Ns is 4, the total number of symbols in which multiple SRS resources are transmitted is 4. It may be expected that, if 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3) are configured for the first SRS resource among the two SRS resources, an SRS resource (the first SRS resource) may be transmitted in the first and third symbols, and that, if other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7) are configured for the second SRS resource, another SRS resource (second SRS resource) may be transmitted in the second and fourth symbols. As another method, it may be expected that the first SRS resource may be transmitted in the first two symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the second SRS resource may be transmitted in the remaining two symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). (The disclosure may not be limited to the above-described examples, and another example in which 4 among the total of 8 antenna ports are configured such as SRS antenna ports 0, 2, 4, 6 may not be excluded.)
The UE may assume that R has the existing definition, that is, refers to the number of consecutive symbols having frequency resources at the same location, in which the corresponding SRS resource is transmitted. Therefore, as described above, the value of R that may be configured for the UE may be a divisor of Ns. Assuming that the UE has N antenna ports configured for multiple SRS resources or has N/n antenna ports configured with regard to each SRS resource (n may be a divisor of N), that SRS resources are transmitted through some of the N antenna ports with regard to each SRS resource, and that M (M may be smaller than or equal to m) symbols are necessary with regard to each SRS resource to transmit SRS resources through all of N antenna ports (that is, a total of n*M OFDM symbols), the minimum value of R may then be 1 or M.
Based on time resource operation 3-1 above, the UE may perform the following operations or operations according to a combination of some thereof according to a combination of startPosition, nrofSymbols, and repetitionFactor, which are higher layer signaling, with regard to periodic/semi-persistent/aperiodic SRS transmission.
The UE may configure the number of symbols in which each of multiple SRS resources is transmitted as the Ns of each SRS resource. Assuming that the UE has N antenna ports or N/n antenna ports configured with regard to each of n SRS resources, that an SRS resource is transmitted through some of the N antenna ports with regard to each SRS resource, and that M symbols are necessary with regard to each SRS resource to transmit an SRS resource through all of N antenna ports, the UE may then expect that all SRS resources may be transmitted through the N antenna ports in a total of M*Ns symbols.
As an example, assuming that n=2 SRS resources that may express N=8 antenna ports are configured for the UE, and each SRS resource is transmitted through four antenna ports in Ns=2 symbols, the UE may then have one of Ns=1, 2, 4, 5, 6, and 7 configured with regard to each of the multiple SRS resources. If Ns is 2, the total number of symbols in which two SRS resources are transmitted is 4. It may be expected that, if 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3) are configured for the first SRS resource among the two SRS resources, an SRS resource (the first SRS resource) may be transmitted in the first and third symbols, and that, if the other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7) are configured for the second SRS resource, another SRS resource (second SRS resource) may be transmitted in the second and fourth symbols. As another method, it may be expected that the first SRS resource may be transmitted in the first two symbols through 4 among the total of 8 antenna ports (for example, SRS antenna ports 0 to 3), and that the second SRS resource may be transmitted in the remaining two symbols through other 4 among the total of 8 antenna ports (for example, SRS antenna ports 4 to 7). (The disclosure may not be limited to the above-described examples, and another example in which 4 among the total of 8 antenna ports are configured such as SRS antenna ports 0, 2, 4, 6 may not be excluded.)
The UE may assume that R has the existing definition, that is, refers to the number of consecutive symbols having frequency resources at the same location, in which the corresponding SRS resource is transmitted. Therefore, as described above, the value of R that may be configured for the UE may be a divisor of Ns. Assuming that the UE has N antenna ports or N/n antenna ports configured with regard to each of n SRS resource, that some of the N antenna ports are transmitted with regard to each SRS resource, and that M symbols are necessary with regard to each SRS resource to transmit all of N antenna ports, the minimum value of R may then be 1 or M.
Based on time resource operation 3-2 above, the UE may perform the following operations or operations according to a combination of some thereof according to a combination of startPosition, nrofSymbols, and repetitionFactor, which are higher layer signaling, with regard to periodic/semi-persistent/aperiodic SRS transmission.
A combination of at least one of [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], and [time resource operation 3-2] described above may be configured for the UE by the base station through higher layer signaling, indicated through L1 signaling, notified of through a combination of higher layer signaling and L1 signaling, activated/deactivated through MAC-CE signaling, or defined within specifications such that the UE operates accordingly.
As an embodiment of the disclosure, a method transmitting/receiving an SRS for antenna switching, based on an assumption that the UE supports an SRS having eight ports as described above, will now be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE.
Regarding the UE's 8T8R operation, higher layer signaling from the base station regarding a combination of at least one of the following details may be configured for the UE, and an operation based thereof may be possible. The following details may be related to a case in which an SRS resource including eight ports is configured for the UE by the base station. (Hereinafter, an SRS resource including A ports may be understood as meaning that A antenna ports are configured in the SRS resource.) That is, the UE may report a value such as t8r8 to the base station through a UE capability report, and the base station may configure one or more SRS resource sets each including one SRS resource including eight ports through higher layer signaling, based thereon. The corresponding SRS resource set may have “usage” which is higher layer signaling configured as “antennaSwitching.”
As an example, if the number of ports configured for each SRS resource is 1, the UE may need a total of eight SRS resources to support 8T8R operation by using such SRS resources. Similarly, as another example, if the number of ports configured for each SRS resource is 2 or 4, the UE may need a total of four or two SRS resources to support 8T8R operation. If transmission of multiple SRS resources, as in above cases, in the same slot is configured or triggered, the UE may be able to perform one of the following operations with regard to whether a guard period including Y OFDM symbols is necessary between two adjacent SRS resources as in existing cases. The guard period including Y OFDM symbols may be based on [Table 36] above, or a value different from the table may be used.
Regarding the UE's 8T8R operation, the base station may configure a combination of at least one of the following details for the UE through higher layer signaling, and the UE may be able to perform operations based thereon. The following details may be based on an assumption that the UE has an SRS resource including one, two, or four SRS ports configured by the base station. That is, they may be understood as methods in which the UE supports 8T8R by expanding existing 1T8R, 2T8R, or 4T8R operation. That is, the UE may report a value such as t1r8, t2r8, or t4r8, for example, to the base station through a UE capability report, and the UE may additionally transmit a UE capability report to the base station to inform that the UE can support 8T8R, based on t1r8, t2r8, or t4r8. Based thereon, the base station may configure, for the UE, one or more SRS resource sets including one or more SRS resources each including one, two, or four ports through higher layer signaling. The corresponding SRS resource set may have “usage” which is higher layer signaling configured as “antennaSwitching.”
SRS resource set having resourceType value of “aperiodic” configured in SRS-ResourceSet which is higher layer signaling may be configured as above.
Maximum of two SRS resource sets: a combination of at least one of the following details may be possible with regard to the corresponding maximum of two SRS resource sets.
As an embodiment of the disclosure, a method for configuring power control parameters during an antenna switching operation of a UE will be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE.
As described above, if the UE operates based on IT4R, and if the UE has multiple SRS resource sets configured by the base station (for example, if two or four SRS resource sets are configured), the UE may expect that respective values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that may be configured in respective SRS resource sets through higher layer signaling, may be configured by the station as the same values in all SRS resource sets, as in the case of the above-mentioned [power control parameter restriction]. That is, the UE may expect that multiple SRS resource sets may all have the same power control parameters.
If such a restriction exists, the UE inevitably performs a method of configuring identical or different power control parameters with regard to each SRS resource set during an antenna switching operation based on multiple SRS resource sets when the UE operates according to 1T4R. This may be inappropriate for a multi-TRP situation in which different power control parameters may be required with regard to each SRS resource set. To the contrary, if such a restriction does not exist during an operation based on multiple SRS resource sets when the UE performs an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of IT2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, IT6R, 1T8R, 2T6R, 2T8R, and 4T8R), the UE may have different transmission power with regard to each pair of connection between transmission and reception antennas expressed through respective SRS resources included in different SRS resource sets. This may cause the occurrence of different estimation errors during channel estimation by the base station. Therefore, as a method for alleviating such a restriction, and UE and the base station may operate according to at least one of the following methods:
During a 1T4R operation using multiple SRS resource sets, the UE may report UE capability which may release the [power control parameter restriction] to the base station. The base station may deliver an intent to release the [power control parameter restriction] during a 1T4R antenna switching operation using multiple SRS resource sets by configuring a specific higher layer signaling parameter only to the UE that transmitted the received UE capability. At the same time, when configuring multiple SRS resource sets for 1T4R for the corresponding UE, the base station may configure respective values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that may be configured in respective SRS resource sets through higher layer signaling, to be identical to or different from each other. Alternatively, when configuring multiple SRS resource sets for 1T4R for the corresponding UE without configuring a specific higher layer signaling parameter, the base station may configure respective values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that may be configured in respective SRS resource sets through higher layer signaling, to be identical to or different from each other. The UE may then expect that, during a 1T4R operation using multiple SRS resource sets, identical or different power control parameters may be configured in respective SRS resource sets, and may perform SRS transmission based thereon.
When the UE uses multiple SRS resource sets during an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of 1T2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, 1T6R, 1T8R, 2T6R, 2T8R, and 4T8R), the UE may report UE capability which may apply the [power control parameter restriction] to the base station. The base station may deliver an intent to apply the [power control parameter restriction] when using multiple SRS resource sets during an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of 1T2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, 1T6R, 1T8R, 2T6R, 2T8R, and 4T8R) by configuring a specific higher layer signaling parameter only to the UE that transmitted the received UE capability. At the same time, when configuring multiple SRS resource sets for an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of 1T2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, IT6R, 1T8R, 2T6R, 2T8R, and 4T8R) for the corresponding UE, the base station may configure respective values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that may be configured in respective SRS resource sets through higher layer signaling, to be equal to each other. Alternatively, when configuring multiple SRS resource sets for an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of 1T2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, IT6R, IT8R, 2T6R, 2T8R, and 4T8R) for the corresponding UE without configuring a specific higher layer signaling parameter, the base station may configure respective values of p0, alpha, pathlossReferenceRS, and srs-PowerControlAdjustmentStates, which are power control parameters that may be configured in respective SRS resource sets through higher layer signaling, to be identical to each other. The UE may then expect that, when using multiple SRS resource sets during an antenna switching operation other than 1T4R (for example, when the UE performs an antenna switching operation regarding one of 1T2R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, IT6R, 1T8R, 2T6R, 2T8R, and 4T8R), identical power control parameters may be configured in respective SRS resource sets, and may perform SRS transmission based thereon.
Above-described [Method 4-1] and [Method 4-2] may correspond to a case in which TCIState or UL-TCIState in dl-OrJoint-TCIStateList which is higher layer signaling is not configured for the UE.
If TCIState or UL-TCIState in dl-OrJoint-TCIStateList which is higher layer signaling is configured for the UE,
If the UE has no followUnifiedTCIstateSRS which is higher layer signaling configured in an SRS resource set, the UE may be provided with values of p0, alpha, and srs-PowerControlAdjustmentStates, based on p0AlphaSetforSRS which is higher layer signaling associated with TCIState or UL-TCIState configured in an SRS resource of the lowest index in the corresponding SRS resource set. pathlossReferenceRS which is higher layer signaling that means a path loss reference signal may be provided based on pathlossReferenceRS-Id-r17 which is higher layer signaling associated with TCIState or UL-TCIState configured in an SRS resource of the lowest index in the corresponding SRS resource set, or included in corresponding TCIState or UL-TCIState.
If TCIState or UL-TCIState in dl-OrJoint-TCIStateList which is higher layer signaling is not configured for the UE, the UE may be provided with p0, alpha, and pathlossReferenceRS which is a path loss reference signal, based on p0, alpha, and pathlossReferenceRS which are higher layer signaling in the corresponding SRS resource set.
If TCIState or UL-TCIState in dl-OrJoint-TCIStateList which is higher layer signaling is configured for the UE,
The base station may configure a combination of at least one of [method 4-1] to [method 4-3] described above for the UE through higher layer signaling, may activate the same through a MAC-CE, may indicate the same through L1 signaling, or may notify of the same through a combination of higher layer signaling and L1 signaling. Alternatively, the same may be fixedly defined in specifications.
The UE may report UE capability to the base station regarding whether a combination of at least one of [method 4-1] to [method 4-4] described above is supported. The UE capability may include at least one component therein so as to indicate whether a combination of at least one of [method 4-1] to [method 4-4] described above is supported, or may be defined as multiple different UE capabilities. If no UE capability is reported regarding a specific method described above, that may be interpreted as possible support for other methods.
[Method 4-1] to [method 4-4] described above may be applied only to SRS resource sets having resource Type value configured for the UE as “aperiodic” in SRS-ResourceSet which is higher layer signaling by the base station.
Alternatively, [method 4-1] to [method 4-4] described above may be applied only to SRS resource sets having resourceType value configured for the UE as “periodic,” “semi-persistent,” or “aperiodic” in SRS-ResourceSet which is higher layer signaling by the base station.
As an embodiment of the disclosure, a method for determining SRS transmission symbol locations in slots during an antenna switching operation of a UE will be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE. In the disclosure, higher layer signaling in an SRS resource may be higher layer signaling/parameter regarding the SRS resource and/or higher layer signaling/parameter included in SRS-Resource (and/or SRS-PosResource). In addition, higher layer signaling in an SRS resource may be higher layer signaling/parameter regarding the SRS resource set and/or higher layer signaling/parameter included in SRS-ResourceSet (and/or SRS-PosResourceSet).
If the UE performs an antenna switching operation by using multiple SRS resource sets with regard to one of 1T2R, 1T4R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, 1T6R, IT8R, 2T6R, 2T8R, and 4T8R, and if the UE has resourceType value configured as “aperiodic” in SRS-ResourceSet which is higher layer signaling by the base station, the UE may expect that all SRS resources in each SRS resource set may be transmitted in different slots, and the UE may expect that respective SRS resources in all SRS resource sets may be transmitted at different OFDM symbol locations.
In such a case, a restriction on OFDM symbol locations of SRS resources in different SRS resource sets that may be transmitted in different slots mean that SRS resources in different SRS resource sets need to have different time resource-related higher layer signaling. This may mean that startPosition or nrofSymbols in resourceMapping, or startPosition-r16 or nrofSymbols-r16 in resourceMapping-r16, or startPosition-r17 or nrofSymbols-r17 in resourceMapping-r17, which is higher layer signaling in respective SRS resources, need to differ from each other. Such a restriction may be an appropriate configuration scheme if the UE transmits respective SRS resource sets in different slots, and if TDD configurations of two slots are different or overlap periodic signal locations, but may be unnecessary in other cases. Therefore, the base station and the UE may operate according to the following methods in order to alleviate such a restriction.
The UE may report UE capability having a meaning that the above-described restriction may be alleviated with regard to SRS resources included in different SRS resource sets to be transmitted in different slots. Upon receiving this, the base station may configure, for the UE, additional higher layer signaling having a meaning that SRS resources included in different SRS resource sets to be transmitted in different slots can be transmitted at identical or different OFDM symbol locations. Alternatively, without configuring additional higher layer signaling, the base station may configure, for the UE, startPosition or nrofSymbols in resourceMapping, or startPosition-r16 or nrofSymbols-r16 in resourceMapping-r16, or startPosition-r17 or nrofSymbols-r17 in resourceMapping-r17, which is higher layer signaling in respective SRS resources, to be identical to or different from each other such that SRS resources included in different SRS resource sets can be transmitted at identical or different OFDM symbol locations. Upon receiving such a higher layer signaling configuration, the UE may perform SRS transmission at OFDM symbol locations configured through startPosition or nrofSymbols in resourceMapping, or startPosition-r16 or nrofSymbols-r16 in resourceMapping-r16, or startPosition-r17 or nrofSymbols-r17 in resourceMapping-r17, which is higher layer signaling in respective SRS resources. As an example, SRS transmission that the UE may consider may be as follows:
As an embodiment of the disclosure, a method for determining a slot offset during aperiodic SRS transmission will be described. The present embodiment may be combined with all embodiments in the disclosure and considered in a base station and a UE.
If the UE performs an antenna switching operation by using multiple SRS resource sets with regard to one of 1T2R, 1T4R, 2T4R, 1T1R, 2T2R, 4T4R, 8T8R, 1T6R, 1T8R, 2T6R, 2T8R, and 4T8R, and if the UE has resourceType value configured as “aperiodic” in SRS-ResourceSet which is higher layer signaling by the base station, the UE may consider a combination of at least one of the following details:
[Method 6-1] The UE may expect that slotOffset which is higher layer signaling in each SRS resource set configured from the base station may have different values.
slotOffset is an offset in number of slots between triggering DCI and the actual transmission of the SRS-ResourceSet.
availableSlotOffsetList is a list of availableSlotOffsets and availableSlotOffset indicates the number of available slots from slot n+k to the slot where the aperiodic SRS resource set is transmitted, where slot n is the slot with the triggering DCI, and k is the slotOffset.
The UE may report UE capability to the base station regarding whether a combination of at least one of [method 6-1] to [method 6-8] described above is supported. The UE capability may include at least one component therein so as to indicate whether a combination of at least one of [method 6-1] to [method 6-8] described above is supported, or may be defined as multiple different UE capabilities. If no UE capability is reported regarding a specific method described above, that may be interpreted as possible support for other methods.
The UE may report UE capability to a base station (21-00). The UE capability report may be a combination of at least one of UE capabilities mentioned in the above-described embodiments. As an example, the UE capability reported by the UE may include at least one of UE capabilities indicating whether [method 1-1] to [method 1-4] are supported, whether [method 1-3-1] to [method 1-3-3] are supported, and whether [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations during antenna switching, and [method 6-1] to [method 6-8] are supported.
The UE may then receive higher layer signaling configuration information from the base station (21-05). The higher layer signaling may be a combination of at least one of pieces of higher layer signaling configuration information mentioned in the above-described embodiments. As an example, the higher layer signaling may be related to at least one of [method 1-1] to [method 1-4], [method 1-3-1] to [method 1-3-3], [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations during antenna switching, and [method 6-1] to [method 6-8] described above.
The UE may additionally receive MAC-CE and/or L1 signaling from the base station (21-10). The MAC-CE and/or L1 signaling may be related to at least one of [method 1-1] to [method 1-4], [method 1-3-1] to [method 1-3-3], [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations in slots during antenna switching, and [method 6-1] to [method 6-8] described above. The UE may transmit an SRS for antenna switching, based on indications received from the base station through the above-described higher layer signaling, MAC CE, and/or L1 signaling (21-15).
Respective steps described in
The base station may receive UE capability from the UE (22-00). The UE capability report may be a combination of at least one of UE capabilities mentioned in the above-described embodiments. As an example, the UE capability reported by the UE may include at least one of UE capabilities indicating whether [method 1-1] to [method 1-4] are supported, whether [method 1-3-1] to [method 1-3-3] are supported, and whether [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations during antenna switching, and [method 6-1] to [method 6-8] are supported.
The base station may then transmit higher layer signaling configuration information to the UE (22-05). The higher layer signaling may be a combination of at least one of pieces of higher layer signaling configuration information mentioned in the above-described embodiments. As an example, the higher layer signaling may be related to at least one of [method 1-1] to [method 1-4], [method 1-3-1] to [method 1-3-3], [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations during antenna switching, and [method 6-1] to [method 6-8] described above.
The base station may additionally transmit MAC-CE and/or L1 signaling to the UE (22-10). As an example, the MAC-CE and/or L1 signaling may be related to at least one of [method 1-1] to [method 1-4], [method 1-3-1] to [method 1-3-3], [time resource operation 2-1], [time resource operation 2-2], [time resource operation 3-1], [time resource operation 3-2], [method 3-1] and [method 3-2], [method 4-1] to [method 4-4], the method for determining SRS transmission symbol locations in slots during antenna switching, and [method 6-1] to [method 6-8] described above. The base station may receive an SRS for antenna switching transmitted by the UE, based on information indicated through the above-described higher layer signaling, MAC CE, and/or L1 signaling (22-15).
Respective steps described in
Referring to
The transceiver may transmit/receive signals with the base station. The signals may include control information and data. To this end, the transceiver may include an RF transmitter configured to up-convert and amplify the frequency of transmitted signals, an RF receiver configured to low-noise-amplify received signals and down-convert the frequency thereof, and the like. This is only an embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and the RF receiver.
In addition, the transceiver may receive signals through a radio channel, output the same to the processor, and transmit signals output from the processor through the radio channel.
The memory may store programs and data necessary for the UE's operations. In addition, the memory may store control information or data included in signals transmitted/received by the UE. The memory may include storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, the UE may include multiple memories.
In addition, the processor may control a series of processes such that the UE can operate according to the above-described embodiments. For example, the processor may control components of the UE so as to receive DCI configured in two layers such that multiple PDSCHs are received simultaneously. The UE may include multiple processors, and the processors may perform the UE's component control operations by executing programs stored in the memory.
Referring to
The transceiver may transmit/receive signals with the UE. The signals may include control information and data. To this end, the transceiver may include an RF transmitter configured to up-convert and amplify the frequency of transmitted signals, an RF receiver configured to low-noise-amplify received signals and down-convert the frequency thereof, and the like. This is only an embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and the RF receiver.
In addition, the transceiver may receive signals through a radio channel, output the same to the processor, and transmit signals output from the processor through the radio channel.
The memory may store programs and data necessary for the base station's operations. In addition, the memory may store control information or data included in signals transmitted/received by the base station. The memory may include storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, the base station may include multiple memories.
The processor may control a series of processes such that the base station can operate according to the above-described embodiments of the disclosure. For example, the processor may control components of the base station so as to configure DCI configured in two layers including allocation information regarding multiple PDSCHs and to transmit the same. The base station may include multiple processors, and the processors may perform the base station's component control operations by executing programs stored in the memory.
The methods according to various embodiments described in the claims or the specification of the disclosure may be implemented by hardware, software, or a combination of hardware and software.
When the methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium may be configured for execution by one or more processors within the electronic device. The at least one program may include instructions that cause the electronic device to perform the methods according to various embodiments of the disclosure as defined by the appended claims and/or disclosed herein.
The programs (software modules or software) may be stored in non-volatile memories including a random access memory and a flash memory, a read only memory (ROM), an electrically erasable programmable read only memory (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other type optical storage devices, or a magnetic cassette. Alternatively, any combination of some or all of them may form a memory in which the program is stored. Further, a plurality of such memories may be included in the electronic device.
In addition, the programs may be stored in an attachable storage device which may access the electronic device through communication networks such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), and Storage Area Network (SAN) or a combination thereof. Such a storage device may access the electronic device via an external port. Further, a separate storage device on the communication network may access a portable electronic device.
In the above-described detailed embodiments of the disclosure, an element included in the disclosure is expressed in the singular or the plural according to presented detailed embodiments. However, the singular form or plural form is selected appropriately to the presented situation for the convenience of description, and the disclosure is not limited by elements expressed in the singular or the plural. Therefore, either an element expressed in the plural may also include a single element or an element expressed in the singular may also include multiple elements.
The embodiments of the disclosure described and shown in the specification and the drawings are merely specific examples that have been presented to easily explain the technical contents of the disclosure and help understanding of the disclosure, and are not intended to limit the scope of the disclosure. That is, it will be apparent to those skilled in the art that other variants based on the technical idea of the disclosure may be implemented. Furthermore, the above respective embodiments may be employed in combination, as necessary. For example, a part of one embodiment of the disclosure may be combined with a part of another embodiment to operate a base station and a terminal. As an example, a part of embodiment 1 of the disclosure may be combined with a part of embodiment 2 to operate a base station and a terminal. Moreover, although the above embodiments have been described based on the FDD LTE system, other variants based on the technical idea of the embodiments may also be implemented in other systems such as TDD LTE, 5G, and NR systems.
In the drawings in which methods of the disclosure are described, the order of the description does not always correspond to the order in which steps of each method are performed, and the order relationship between the steps may be changed or the steps may be performed in parallel.
Alternatively, in the drawings in which methods of the disclosure are described, some elements may be omitted and only some elements may be included therein without departing from the essential spirit and scope of the disclosure.
Furthermore, in methods of the disclosure, some or all of the contents of each embodiment may be implemented in combination without departing from the essential spirit and scope of the disclosure.
Various embodiments of the disclosure have been described above. The above description of the disclosure is merely for the purpose of illustration, and embodiments of the disclosure are not limited to the embodiments set forth herein. Those skilled in the art will appreciate that other particular modifications and changes may be easily made without departing from the technical idea or the essential features of the disclosure. The scope of the disclosure should be determined not by the above description but by the appended claims, and all modifications or changes derived from the meaning and scope of the claims and equivalent concepts thereof shall be construed as falling within the scope of the disclosure.
Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0001931 | Jan 2023 | KR | national |
