Patent Application
20230292304
The disclosure relates to a method and device for changing an uplink-downlink configuration in a wireless communication system.
In order to meet the demand for wireless data traffic soaring since the 4th generation (4G) communication system came to the market, there are ongoing efforts to develop enhanced 5th generation (5G) communication systems or pre-5G communication systems. For the reasons, the 5G communication system or pre-5G communication system is called the beyond 4G network communication system or post long-term evolution (LTE) system.
For higher data transmit rates, 5G communication systems are considered to be implemented on ultra-high frequency bands (mmWave), such as, e.g., 60 GHz. To mitigate pathloss on the ultra-high frequency band and increase the reach of radio waves, the following techniques are taken into account for the 5G communication system, beamforming, massive multi-input multi-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large scale antenna.
Also being developed are various technologies for the 5G communication system to have an enhanced network, such as evolved or advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-point (CoMP), and reception interference cancellation.
There are also other various schemes under development for the 5G system including, e.g., hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA), which are advanced access schemes.
The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged. As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “Security technology” have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been recently researched. Such an IoT environment may provide intelligent Internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud Radio Access Network (RAN) as the above-described Big Data processing technology may also be considered to be as an example of convergence between the 3eG technology and the IoT technology.
As described above, as wireless communication systems evolve to provide various services, a need arises for a method for smoothly providing such services. In particular, techniques for flexibly allocating uplink resources and downlink resources in the time domain and frequency domain are required for additional coverage extension.
Embodiments of the disclosure provide a method and device for changing an uplink-downlink configuration in a wireless communication system.
The disclosure provides a method and device for applying a changed uplink-downlink configuration when changing an uplink-downlink configuration.
The disclosure provides a method and device for applying a latency before starting a transmission/reception operation according to a changed uplink-downlink configuration.
The disclosure provides a method and device for applying a changed uplink-downlink configuration when a change occurs between uplink and downlink in a specific frequency resource due to a change in uplink-downlink configuration.
The disclosure provides a method and device for applying a changed uplink-downlink configuration after a latency according to a predetermined condition when changing an uplink-downlink configuration.
According to an embodiment of the disclosure, a method by a base station configured to change an uplink-downlink configuration in a wireless communication system may comprise transmitting uplink-downlink configuration information indicating a first uplink-downlink configuration to a UE, transmitting a change indicator indicating a second uplink-downlink configuration to the UE, determining whether an uplink-downlink direction is changed in a specific frequency domain resource based on a change from the first uplink-downlink configuration to the second uplink-downlink configuration, and based on the uplink-downlink direction being changed, communicating with the UE on the frequency domain resource according to the second uplink-downlink configuration after a change delay time predetermined from transmission of the change indicator.
According to an embodiment of the disclosure, a method by a UE configured to change an uplink-downlink configuration in a wireless communication system may comprise receiving uplink-downlink configuration information indicating a first uplink-downlink configuration from a base station, receiving a change indicator indicating a second uplink-downlink configuration from the base station, determining whether an uplink-downlink direction is changed in a specific frequency domain resource based on a change from the first uplink-downlink configuration to the second uplink-downlink configuration, and based on the uplink-downlink direction being changed, communicating with the base station on the frequency domain resource according to the second uplink-downlink configuration after a change delay time predetermined from transmission of the change indicator.
According to an embodiment of the disclosure, a device of a base station configured to change an uplink-downlink configuration in a wireless communication system may comprise a transceiver configured to transmit uplink-downlink configuration information indicating a first uplink-downlink configuration to a UE and transmit a change indicator indicating a second uplink-downlink configuration to the UE and a processor configured to determine whether an uplink-downlink direction is changed in a specific frequency domain resource based on a change from the first uplink-downlink configuration to the second uplink-downlink configuration and, based on the uplink-downlink direction being changed, control the transceiver to communicate with the UE according to the second uplink-downlink configuration after a change delay time predetermined from transmission of the change indicator.
According to an embodiment of the disclosure, a device of a UE configured to change an uplink-downlink configuration in a wireless communication system may comprise a transceiver configured to receive uplink-downlink configuration information indicating a first uplink-downlink configuration from a base station and transmit a change indicator indicating a second uplink-downlink configuration to the base station and a processor configured to determine whether an uplink-downlink direction is changed in a specific frequency domain resource based on a change from the first uplink-downlink configuration to the second uplink-downlink configuration and, based on the uplink-downlink direction being changed, control the transceiver to communicate with the base station according to the second uplink-downlink configuration after a change delay time predetermined from transmission of the change indicator.
According to the disclosed embodiments, it is possible to effective changing an uplink-downlink configuration in a wireless communication system.
Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings.
In describing the embodiments, the description of technologies that are known in the art and are not directly related to the disclosure is omitted. This is for further clarifying the gist of the present disclosure without making it unclear.
For the same reasons, some elements may be exaggerated or schematically shown. The size of each element does not necessarily reflect the real size of the element. The same reference numeral is used to refer to the same element throughout the drawings.
Advantages and features of the present disclosure, and methods for achieving the same may be understood through the embodiments to be described below taken in conjunction with the accompanying drawings. However, the scope of the disclosure is not limited to the embodiments disclosed herein, and various changes may be made thereto. The embodiments disclosed herein are provided only to inform one of ordinary skilled in the art of the category of the disclosure. The disclosure is defined only by the appended claims. The same reference numeral denotes the same element throughout the specification. When determined to make the subject matter of the present invention unclear, the detailed description of the known art or functions may be skipped. The terms as used herein are defined considering the functions in the present disclosure and may be replaced with other terms according to the intention or practice of the user or operator. Therefore, the terms should be defined based on the overall disclosure.
Hereinafter, the base station (BS) may be an entity allocating resource to a user equipment (UE) and may be at least one of gNode B, eNode B, Node B, radio access unit, base station controller, or node over network. The user equipment (UE) may include a mobile station (MS), cellular phone, smartphone, computer, or multimedia system capable of performing communication functions. In the disclosure, downlink (DL) refers to a wireless transmission path of signal transmitted from the base station to the UE, and uplink (UL) refers to a wireless transmission path of signal transmitted from the UE to the base station. Although LTE, LTE-A, or 5G systems may be described below as an example, the embodiments may be applied to other communication systems having a similar technical background or channel pattern. For example, 5G mobile communication technology (or new radio, NR) developed after LTE-A may be included therein, and 5G below may be a concept including legacy LTE, LTE-A and other similar services. Further, the embodiments may be modified in such a range as not to significantly depart from the scope of the present invention under the determination by one of ordinary skill in the art and such modifications may be applicable to other communication systems.
It should be appreciated that the blocks in each flowchart and combinations of the flowcharts may be performed by computer program instructions. Since the computer program instructions may be equipped in a processor of a general-use computer, a special-use computer or other programmable data processing devices, the instructions executed through a processor of a computer or other programmable data processing devices generate means for performing the functions described in connection with a block(s) of each flowchart. Since the computer program instructions may be stored in a computer-available or computer-readable memory that may be oriented to a computer or other programmable data processing devices to implement a function in a specified manner, the instructions stored in the computer-available or computer-readable memory may produce a product including an instruction means for performing the functions described in connection with a block(s) in each flowchart. Since the computer program instructions may be equipped in a computer or other programmable data processing devices, instructions that generate a process executed by a computer as a series of operational steps are performed over the computer or other programmable data processing devices and operate the computer or other programmable data processing devices may provide steps for executing the functions described in connection with a block(s) in each flowchart.
Further, each block may represent a module, segment, or part of a code including one or more executable instructions for executing a specified logical function(s). Further, it should also be noted that in some replacement execution examples, the functions mentioned in the blocks may occur in different orders. For example, two blocks that are consecutively shown may be performed substantially simultaneously or in a reverse order depending on corresponding functions.
As used herein, the term “unit” means a software element or a hardware element such as a field-programmable gate array (FPGA) or an application specific integrated circuit (ASIC). A unit plays a certain role. However, the term “unit” is not limited as meaning a software or hardware element. A ‘unit’ may be configured in a storage medium that may be addressed or may be configured to reproduce one or more processors. Accordingly, as an example, a ‘unit’ includes elements, such as software elements, object-oriented software elements, class elements, and task elements, processes, functions, attributes, procedures, subroutines, segments of program codes, drivers, firmware, microcodes, circuits, data, databases, data architectures, tables, arrays, and variables. A function provided in an element or a ‘unit’ may be combined with additional elements or may be split into sub elements or sub units. Further, an element or a ‘unit’ may be implemented to reproduce one or more CPUs in a device or a security multimedia card. Further, in the disclosure, a “...unit” may include one or more processors.
Wireless communication systems evolve beyond voice-centered services to broadband wireless communication systems to provide high data rate and high-quality packet data services, such as 3rd generation partnership project (3GPP) high speed packet access (HSPA), long term evolution (LTE) or evolved universal terrestrial radio access (E-UTRA)), LTE-advanced (LTE-A), LTE-pro, 3GPP2 high rate packet data (HRPD), ultra-mobile broadband (UMB), or institute of electrical and electronics engineers (IEEE) 802.16e communication standards.
As a representative example of such broadband wireless communication system, LTE system adopts orthogonal frequency division multiplexing (OFDM) for downlink and single carrier frequency division multiple access (SC-FDMA) for uplink. Uplink means a wireless link where the UE transmits data or control signals to the base station (BS), and download means a wireless link where the base station transmits data or control signals to the UE. Such multiple access scheme may typically allocate and operate time-frequency resources carrying data or control information per user not to overlap, i.e., to maintain orthogonality, to thereby differentiate each user’s data or control information.
Post-LTE communication systems, e.g., 5G communication systems, are required to freely reflect various needs of users and service providers and thus to support services that simultaneously meet various requirements. Services considered for 5G communication systems include, e.g., enhanced mobile broadband (eMBB), massive machine type communication (MMTC), and ultra-reliability low latency communication (URLLC).
eMBB aims to provide a further enhanced data transmission rate as compared with LTE, LTE-A, or LTE-pro. For example, eMBB for 5G communication systems needs to provide a peak data rate of 20 Gbps on download and a peak data rate of 10Gbps on uplink in terms of one base station. 5G communication systems also need to provide an increased user perceived data rate while simultaneously providing such peak data rate. To meet such requirements, various transmit (TX)/receive (RX) techniques, as well as multiple input multiple output (MIMO), need to further be enhanced. While LTE adopts a TX bandwidth up to 20 MHz in the 2 GHz band to transmit signals, the 5G communication system employs a broader frequency bandwidth in a frequency band ranging from 3 GHz to 6 GHz or more than 6 GHz to meet the data rate required for 5G communication systems.
mMTC is also considered to support application services, such as internet of things (IoT) in the 5G communication system. To efficiently provide IoT, mMTC is required to support massive UEs in the cell, enhance the coverage of the UE and the battery time, and reduce UE costs. IoT devices are attached to various sensors or devices to provide communication functionality, and thus, it needs to support a number of UEs in each cell (e.g., 1,000,000 UEs/km2). Since mMTC-supportive UEs, by the nature of service, are highly likely to be located in shadow areas not covered by the cell, such as the underground of a building, it may require much broader coverage as compared with other services that the 5G communication system provides. mMTC-supportive UEs, due to the need for being low cost and difficulty in frequently exchanging batteries, may be required to have a very long battery life, e.g., 10 years to 15 years.
URLLC is a mission-critical, cellular-based wireless communication service. For example, there may be considered a service for use in at least one of remote control for robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, or emergency alert. This requires that URLLC provide very low-latency and very high-reliability communication. For example, URLLC-supportive services need to meet an air interface latency of less than 0.5 milliseconds simultaneously with a packet error rate of 75 or less. Thus, for URLLC-supportive services, the 5G communication system may be required to provide a shorter transmit time interval (TTI) than those for other services while securing reliable communication links by allocating a broad resource in the frequency band.
The three 5G services, i.e., eMBB, URLLC, and mMTC, may be multiplexed in one system and be transmitted. In this case, the services may adopt different TX/RX schemes and TX/RX parameters to meet their different requirements. Of course, 5G is not limited to the above-described three services.
The frame structure of the 5G system is described below in more detail with reference to the drawings.
Referring to
(e.g.,, 12) consecutive REs may constitute one resource block (RB) 104.
of symbols per slot=14). One subframe 201 may be composed of one or more slots 202 or 203, and the number of slots 202 or 203 per subframe 201 is determined depending on µ 204 or 205, which is a setting value for the subcarrier spacing (SCS). In the illustrated example, the subcarrier spacing setting value µ=0 (204) and the subcarrier spacing setting value µ=1 (205). When µ = 0 (204), one subframe 201 may consist of one slot 202, and when µ = 1 (205), one subframe 201 may consist of two slots (203). In other words, according to the set subcarrier spacing value µ, the number
of slots per subframe may vary, and accordingly, the number
of slots per frame may differ. According to each subcarrier spacing µ,
and
slot may be defined in Table 1 below.
A configuration of a bandwidth part (BWP) in a 5G wireless communication system is described below with reference to the drawings.
Here, bwp-Id means the bandwidth part identifier, locationAndBandwidth indicates the location of the bandwidth part, subcarrierSpacing indicates the subcarrier spacing, and cyclicPrefix indicates the length of the cyclic prefix (CP).
The configuration of the bandwidth part is not limited thereto, other various BWP-related parameters than the above-described configuration information may be configured in the UE. The base station may transmit the configuration information to the UE through higher layer signaling, e.g., radio resource control (RRC) signaling. At least one bandwidth part among one or more configured bandwidth parts may be activated. Whether to activate the configured bandwidth part may be transmitted from the base station to the UE semi-statically through RRC signaling or dynamically through downlink control information (DCI).
Before radio resource control (RRC) connected, the UE may be configured with an initial bandwidth part (BWP) for initial access by the base station via a master information block (MIB). The UE may receive configuration information about the search space and control resource set (CORESET) in which the physical downlink control channel (PDCCH) may be transmitted through the MIB in the initial access phase. Each of the control resource set and search space configured with the MIB may be regarded as identity (ID) 0. The base station may provide the UE with at least one or more pieces of information among the frequency allocation information, time allocation information, and numerology for control resource set #0 through the MIB. Here, the numerology may include at least one of the subcarrier spacing or cyclic prefix (CP). Here, CP may mean at least one of the length of the CP or information corresponding to the CP length (e.g., normal CP length or extended CP length). Further, the base station may provide the UE with configuration information for occasion and monitoring period for control resource set #0, i.e., configuration information for search space #0, via the MIB. The UE may regard the frequency range set as control resource set #0 obtained from the MIB, as the initial BWP for initial access. In this case, the identity (ID) of the initial BWP may be regarded as 0.
The configuration of the bandwidth part supported by the 5G wireless communication system described above may be used for various purposes.
When the bandwidth supported by the UE is smaller than the system bandwidth, the configuration for the bandwidth part may be used. For example, the base station may configure the frequency domain position of the bandwidth part in the UE (e.g., by the configuration information of the higher layer) to allow the UE to transmit/receive data in a specific frequency position in the system bandwidth.
For the purpose of supporting different numerologies, the base station may configure the UE with a plurality of bandwidth parts. For example, to support data transmission/reception using a subcarrier spacing of 15 kHz and a subcarrier spacing of 30 kHz for some UE, the base station may configure the UE with two bandwidths, as subcarrier spacings of 15 kHz and 30 kHz. The different bandwidth parts may be frequency division multiplexed and, when the base station transmits/receives data at a specific subcarrier spacing, the bandwidth part set as the specific subcarrier spacing may be activated.
For the purpose of reducing power consumption of the UE, the base station may configure the UE with bandwidth parts having different sizes of bandwidths. For example, although the UE may support a very large bandwidth, e.g., a bandwidth of 100 MHz, transmission/reception of data always using the entire bandwidth may cause significantly large power consumption. In particular, it is very inefficient in terms of power consumption to monitor an unnecessary downlink control channel using a large bandwidth of 100 MHz in a situation where there is no traffic. For the purpose of reducing power consumption of the UE, the base station may configure a bandwidth part of a relatively small bandwidth to the UE, e.g., a bandwidth part of 20 Mhz, in the UE. In a no-traffic situation, the UE may perform monitoring in the 20 MHz bandwidth and, if data occurs, the UE may transmit/receive data in the 100 MHz bandwidth according to an instruction from the base station.
As described above, UEs before RRC connected may receive configuration information for the initial bandwidth part via MIB in the initial access phase. The UE may be configured with a control resource set (CORESET) for a downlink control channel (PDCCH) from the MIB of a physical broadcast channel (PBCH). The bandwidth of the control resource set configured through the MIB may be regarded as the initial bandwidth part, and the UE may receive the physical downlink shared channel (PDSCH), which transmits the SIB, via the configured initial bandwidth part. The UE may detect the PDCCH on the search space and the control resource set in the initial bandwidth part configured with the MIB, receive remaining system information (RMSI) or system information block (SIB)1 necessary for initial access through the PDSCH scheduled by the PDCCH, and obtain configuration information regarding the uplink initial bandwidth part through the SIB1 (or RMSI). The initial BWP may be utilized for other system information (OSI), paging, and random access as well as for receiving SIB.
If the UE is configured with one or more BWPs, the base station may indicate, to the UE, a change in BWP using the BWP indicator in the DCI. As an example, when the currently activated bandwidth part of the UE is bandwidth part#1 305 in
As described above, the DCI-based bandwidth part change may be indicated by the DCI scheduling PDSCH or physical uplink shared channel (PUSCH). When the UE receives a request for changing the bandwidth part in the DCI, the UE should be able to receive or transmit the PDSCH or PUSCH scheduled by the DCI without any trouble in the changed bandwidth part. To that end, the standard specified requirements for delay time TBWP required upon changing bandwidth part, which may be defined as shown in Table 3 below.
The requirement for delay of bandwidth part change may support type 1 or type 2 according to the capability of the UE. The UE may report a supportable bandwidth part delay time type to the base station.
If the UE receives, in slot n, DCI including a bandwidth part change indicator according to the above-described requirements for 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 time not later than slot n+TBWP, and may perform transmission/reception on the data channel scheduled by the DCI in the changed, new bandwidth part. Upon scheduling data channel in the new bandwidth part, the base station may determine time domain resource allocation for data channel considering the UE’s bandwidth part change delay time TBWP. In other words, when scheduling a data channel with the new bandwidth part, in a method for determining a time domain resource allocation for the data channel, the base station may schedule a corresponding data channel after the bandwidth part change delay time. Thus, the UE may not expect that the DCI indicating the bandwidth part change indicates a slot offset (K0 or K2) smaller than the bandwidth part change delay time TBWP.
If the UE has received the DCI (e.g., DCI format 1_1 or 0_1) indicating the bandwidth part change, the UE may perform no transmission or reception during the time period from the third symbol of the slot in which the PDCCH including the DCI has been received to the start symbol of the slot indicated by the slot offset (K0 or K2) value indicated by the time domain resource allocation field in the DCI. For example, if the UE receives the DCI indicating a bandwidth part change in slot n, and the slot offset value indicated by the DCI is K, the UE may perform no transmission or reception from the third symbol of slot n to a symbol before a previous symbol of slot n+K (i.e., the last symbol of slot n+K-1).
Next, the synchronization signal (SS)/PBCH block in the 5G wireless communication system is described.
The SS/PBCH block may mean a physical layer channel block composed of primary SS (PSS), secondary SS (SSS), and PBCH described below.
PSS: A signal that serves as a reference for downlink time/frequency synchronization and provides part of the information for cell ID.
SSS: serves as a reference for downlink time/frequency synchronization, and provides the rest of the information for cell ID, which PSS does not provide. Additionally, it may serve as a reference signal (RS) for demodulation of PBCH.
PBCH: provides essential system information necessary for the UE to transmit and receive data channel and control channel. The essential system information may include at least one of search space-related control information indicating radio resource mapping information for a control channel or scheduling control information for a separate data channel for transmitting system information.
SS/PBCH block: The SS/PBCH block is composed of a combination of PSS, SSS, and PBCH. One or more SS/PBCH blocks may be transmitted within 5 ms, and each transmitted SS/PBCH block may be distinguished with an index.
The UE may detect the PSS and SSS in the initial access phase and may decode the PBCH. The UE may obtain the MIB from the PBCH and may be therefrom configured with control resource set (CORESET) #0 (which may correspond to a control resource set having a control resource set index of 0). The UE may perform monitoring on control resource set #0, assuming that the selected SS/PBCH block and the demodulation reference signal (DMRS) transmitted in control resource set #0 are quasi-co-located (QCLed). The UE may receive system information using the downlink control information transmitted in control resource set #0. The UE may obtain configuration information related to random access channel (RACH) required for initial access from the received system information. The UE may transmit the physical RACH (PRACH) to the base station considering the selected SS/PBCH index, and the base station receiving the PRACH may obtain the SS/PBCH block index selected by the UE. The base station may know which block the UE has selected from the SS/PBCH blocks and monitors control resource set #0 related thereto.
Next, downlink control information (DCI) in the 5G wireless communication system is described.
In the 5G system, scheduling information for uplink data (or PUSCH) or downlink data (or PDSCH) may be transmitted from the base station to the UE through the DCI. The UE may attempt to monitor or detect at least one of the DCI format for fallback and the DCI format for non-fallback for the PUSCH or PDSCH. The fallback DCI format may be composed of fields predetermined between the base station and the UE, and the non-fallback DCI format may include configurable fields.
DCI may be transmitted through the physical downlink control channel (PDCCH), via channel coding and modulation. A cyclic redundancy check (CRC) is added to the payload of the DCI, and the CRC is scrambled with the radio network temporary identifier (RNTI) that is the identity of the UE. Different RNTIs may be used depending on the purposes of the DCI, e.g., at least one of UE-specific data transmission, power control command, or random access response. In other words, the RNTI is not explicitly transmitted, but the RNTI is included in the CRC calculation process and transmitted. Upon receiving the DCI transmitted on the PDCCH, the UE may check the CRC using the allocated RNTI, and when the result of the CRC check is successful, the UE may be aware that the DCI has been transmitted to the UE.
For example, DCI scheduling a PDSCH for system information (SI) may be scrambled to SI-RNTI. DCI scheduling a PDSCH for a random access response (RAR) message may be scrambled to RA-RNTI. DCI scheduling a PDSCH for a paging message may be scrambled with P-RNTI. DCI providing a slot format indicator (SFI) may be scrambled to SFI-RNTI. DCI providing transmit power control (TPC) may be scrambled to TPC-RNTI. DCI scheduling UE-specific PDSCH or PUSCH may be scrambled with any one of the cell RNTI (C-RNTI), modulation coding scheme C-RNTI (MCS-C-RNTI), or configured scheduling RNTI (CS-RNTI).
DCI format 0_0 may be used as fallback DCI for scheduling PUSCH, and in this case, CRC may be scrambled to C-RNTI. DCI format 0_0 in which CRC is scrambled to C-RNTI may include, e.g., the fields as shown in Table 4 below.
DCI format 0_1 may be used as non-fallback DCI for scheduling PUSCH, and in this case, CRC may be scrambled to C-RNTI. DCI format 0_1 in which CRC is scrambled to C-RNTI may include, e.g., the information shown in Table 5 below.
DCI format 1_0 may be used as fallback DCI for scheduling PDSCH, and in this case, CRC may be scrambled to C-RNTI. DCI format 1_0 in which CRC is scrambled to C-RNTI may include, e.g., the information shown in Table 6 below.
DCI format 1_1 may be used as non-fallback DCI for scheduling PDSCH, and in this case, CRC may be scrambled to C-RNTI. DCI format 1_1 in which CRC is scrambled to C-RNTI may include, e.g., the information shown in Table 7 below.
Hereinafter, a method for allocating time domain resources for a data channel in a 5G wireless communication system is described.
The base station may configure the UE with a table for time domain resource allocation for a downlink data channel (PDSCH) and an uplink data channel (PUSCH) via higher layer signaling (e.g., RRC signaling).
For PDSCH, a table including up to maxNrofDL-Allocations=16 entries may be configured and, for PUSCH, a table including up to maxNrofUL-Allocations=16 entries may be configured. The time domain resource allocation information may include at least one of, e.g., PDCCH-to-PDSCH slot timing (which is designated K0 and corresponds to the time interval between the time of reception of the PDCCH and the time of transmission of the PDSCH scheduled by the received PDCCH) or PDCCH-to-PUSCH slot timing (which is designated K2 and corresponds to the time interval between the time of PDCCH and the time of transmission of the PUSCH scheduled by the received PDCCH), information for the position and length of the start symbol where the PDSCH or PUSCH is scheduled in the slot, and the mapping type of PDSCH or PUSCH. For example, information as illustrated in Tables 8 and 9 below may be provided from the base station to the UE.
Here, K0 indicates the PDCCH-to-PDSCH timing in the slot unit, mappingType indicates the PDSCH mapping type, and startSymbolAndLength indicates the start symbol and length of the PDSCH.
Here, K2 indicates the PDCCH-to-PUSCH timing in the slot unit, mappingType indicates the PUSCH mapping type, and startSymbolAndLength indicates the start symbol and length of the PUSCH.
The base station may provide the UE with one of the entries in the table for the time domain resource allocation information via layer 1 (L1) signaling (e.g., DCI) (e.g., it may be indicated with the ‘time domain resource allocation’ field in the DCI). The UE may obtain time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.
Hereinafter, a method for allocating frequency domain resources for a data channel in a 5G wireless communication system is described.
The 5G wireless communication system supports two types, i.e., resource allocation type 0 and resource Supports allocation type 1, as methods for indicating frequency domain resource allocation information for the physical downlink shared channel (PDSCH) and the physical uplink shared channel (PUSCH).
RB allocation information may be provided from the base station to the UE in the form of a bitmap for a resource block group (RBG). In this case, the RBG may be composed of a set of contiguous virtual RBs, and the size P of the RBG may be determined based on a value set as a higher layer parameter (rbg-Size) and the bandwidth part size defined in Table 10 below.
Here, the total number (NRBG) of RBGs in bandwidth part i with a size of
. Here, the size of the first RBG is
. The size
of the last RBG is
if,
otherwise
is P. The size of the RBGs other than the RBG is P.
Each bit in the bitmap with a size of NRBG bits may correspond to its respective RBG. The RBGs may be indexed in ascending order of frequency, starting from the position of lowest position of the bandwidth part. For NRBG RBGs in the bandwidth part, RBG#0 to RBG#(NRBG -1) may be mapped to the most significant bit (MSB) to the least significant bit (LSB) of the RBG bitmap. When a specific bit value in the bitmap is 1, the UE may determine that an RBG corresponding to the bit value has been assigned and, when the specific bit value in the bitmap is 0, the UE may determine that no RBG is assigned corresponding to the bit value.
RB allocation information may be provided from the base station to the UE, as information for the start position and length for the VRBs contiguously assigned. In this case, interleaving or non-interleaving may be further applied to the contiguously assigned VRBs. The resource allocation field of resource allocation field type 1 may be configured with a resource indication value (RIV), and the RIV may be composed of the start position (RBstart) of the VRBs and the length (LRBs) of the contiguously allocated RBs. In an embodiment, the RIV in the bandwidth part of the
size may be defined as below.
The base station may configure the UE with a resource allocation type through higher layer signaling (e.g., the higher layer parameter resourceAllocation may be set to one of resourceAllocationType0, resourceAllocationTypel, or dynamicSwitch). If the UE has been configured with both resource allocation types 0 and 1 (or if the higher layer parameter resourceAllocation is set to dynamicSwitch in the same manner), it may indicate whether the bit corresponding to the most significant bit (MSB) of the field indicating resource allocation in the DCI format indicating scheduling is resource allocation type 0 or resource allocation type 1. Further, the resource allocation information may be indicated through the remaining bits except for the bit corresponding to the MSB based on the indicated resource allocation type, and the UE may interpret the resource allocation field information of the DCI field based thereupon. If the UE is configured with either resource allocation type 0 or resource allocation type 1 (or if the higher layer parameter resourceAllocation is set to either resourceAllocationType0 or resourceAllocationTypel in the same manner), resource allocation information may be indicated based on the resource allocation type in which a field is configured indicating the resource allocation in the DCI format indicating scheduling and, based thereupon, the UE may interpret the resource allocation field information for the DCI field.
A modulation and coding scheme used in the 5G wireless communication system is described below.
In 5G, a plurality of MCS index tables are defined for PDSCH and PUSCH scheduling. Which MCS table is to be assumed among the plurality of MCS tables may be set or indicated through higher layer signaling or L1 signaling from the base station to the UE or through the RNTI assumed by the UE upon PDCCH decoding.
The MCS index table for PDSCH and CP-OFDM-based PUSCH (or PUSCH without transform precoding) may be as shown in Table 11 below.
The MCS index table for PDSCH and CP-OFDM-based PUSCH (or PUSCH without transform precoding) may be as shown in Table 12.
The MCS index table for PDSCH and CP-OFDM-based PUSCH (or PUSCH without transform precoding) may be as shown in Table 13 below.
MCS index Table 1 for DFT-s-OFDM-based PUSCH (or PUSCH with transform precoding) may be as shown in Table 14.
MCS index Table 2 for DFT-s-OFDM-based PUSCH (or PUSCH with transform precoding) may be as shown in Table 15.
The MCS index table for the PUSCH to which transform precoding or discrete Fourier transform (DFT) precoding and 64 QAM is applied may be as shown in Table 16 below.
The MCS index table for the PUSCH to which transform precoding or DFT precoding and 64 QAM is applied may be as shown in Table 17 below.
A downlink control channel in the 5G wireless communication system is described below with reference to the drawings.
Referring to
Each control resource set described above may be configured by the base station to the UE through higher layer signaling, e.g., at least one of system information, MIB, or RRC signaling. Configuring the UE with the control resource set means providing at least one piece of information among the control resource set identity, frequency position of the control resource set, or symbol length of the control resource set. For example, the higher layer signaling information elements to configure the control resource set may include information as shown in Table 18.
Here, tci-StatesPDCCH is configuration information about the transmission configuration indication (TCI) states and may include one or more synchronization signal (SS)/physical broadcast channel (PBCH) block indexes or channel state information reference signal (CSI-RS) indexes having a quasi-co-located (QCL) relationship with the DMRS transmitted in the corresponding control resource set.
Referring to
When the basic unit in which the downlink control channel is allocated is a control channel element (CCE) 504, one CCE 504 may be constituted of a plurality of REGs 503. In the example of the illustrated REG 503, the REG 503 may be constituted of 12 REs, and if one CCE 504 is constituted of six REGs 503, one CCE 504 may be constituted of 72 REs. The region where the downlink control resource set is configured may be constituted of a plurality of CCEs 504, and a specific downlink control channel may be mapped to one or more CCEs 504 according to the aggregation level (AL) in the control resource set and be transmitted. The CCEs 504 in the control resource set are distinguished with numbers, and in this case, the numbers of the CCEs 504 may be assigned according to a logical mapping scheme.
The basic unit of the downlink control channel, i.e., REG 503, may include both the region of the REs to which the DCI is mapped and the region where the DMRS 505 used to demodulate the DCI is mapped. At least one (three in the illustrated example) DMRS 505 may be transmitted in one REG 503. The number of CCEs necessary to transmit a PDCCH may be, e.g., 1, 2, 4, 8, or 16 depending on the aggregation level (AL), and different numbers of CCEs may be used to implement link adaptation of downlink control channel. For example, if AL=L, one downlink control channel may be transmitted via L CCEs.
The UE needs to detect a signal in the control resource set while being unaware of information for downlink control channel and, for such blind decoding, a search space is defined which indicates a set of CCEs. The search space is a set of candidate control channels constituted of CCEs that the UE needs to attempt to decode on the given aggregation level, and since there are several aggregation levels to bundle up 1, 2, 4, 8, or 16 CCEs, the UE has a plurality of search spaces. A search space set (Set) may be defined as a set of search spaces at all set aggregation levels.
Search spaces for PDCCH may be classified into a common search space and a UE-specific search space. A predetermined group of UEs or all the UEs may search for the common search space to receive cell-common control information, e.g., paging message, or dynamic scheduling for system information. For example, PDSCH scheduling allocation information for transmission of the SIB including cell service provider may be detected by inspecting the common search space. The common search space may be defined as a set of pre-agreed CCEs to allow a predetermined group of UEs or all the UEs to receive the PDCCH. Scheduling allocation information for the UE-specific PDSCH or PUSCH may be received by inspecting the UE-specific search space. The UE-specific search space may be UE-specifically defined with a function of various system parameters and the identity of the UE.
In the 5G wireless communication system, the parameters for the search space for the PDCCH may be configured in the UE by the base station through higher layer signaling (e.g., SIB, MIB, or RRC signaling). For example, the base station may configure the UE with, e.g., the number of PDCCH candidates at each aggregation level L, monitoring period for search space, monitoring occasion of symbol unit in slot for search space, search space type (common search space or UE-specific search space), combination of RNTI and DCI format to be monitored in the search space, or control resource set index to be monitored in the search space. For example, the higher layer signaling information elements to configure the search space of the PDCCH may include the parameters as shown in Table 19.
According to the configuration information, the base station may configure one or more search space sets to the UE. The base station may configure the UE with search space set 1 and search space set 2 and configure it to monitor DCI format A, scrambled to X-RNTI in search space set 1, in the common search space and to monitor DCI format B, scrambled to Y-RNTI in search space set 2, in the UE-specific search space.
According to the above-described configuration information, one or more search space sets may be present in the common search space or the UE-specific search space. For example, search space set#1 and search space set#2 may be configured as the common search space, and search space set#3 and search space set#4 may be configured as the UE-specific search space.
In the common search space, e.g., a combination of DCI format and RNTI as follows may be monitored. Of course, it is not limited to the examples described below.
In the UE-specific search space, e.g., a combination of DCI format and RNTI as follows may be monitored. Of course, it is not limited to the examples described below.
The RNTIs may be defined and used as follows.
The above-described DCI formats may follow the definitions in Table 20 below.
In the 5G wireless communication system, the search space of the aggregation level L in the control resource set p and the search space set s may be expressed by Equation 1 below.
In the case of the UE-specific search space, Y_(p,nµs,f) may have a value that changes depending on the UE’s identity (C-RNTI or ID configured in the UE by the base station) and the time index.
Referring to
First, the uplink-downlink configuration 610 of the symbol/slot may be semi-statically indicated through cell-specific configuration information through the system information in the symbol unit. In an embodiment, the cell-specific uplink-downlink configuration information may include uplink-downlink pattern information and reference subcarrier spacing information. The uplink-downlink pattern information may include the periodicity 603 at which one DL-UL pattern is applied, the number 611 of consecutive full DL slots at the beginning of each DL-UL pattern), the number 612 of consecutive DL symbols in the beginning of the slot following the last full DL slot, the number 613 of consecutive full UL slots at the end of each DL-UL pattern, or the number 614 of consecutive UL symbols in the end of the slot preceding the first full UL slot. In this case, slots and symbols not indicated by uplink or downlink may be determined as flexible slots/symbols.
Second, the UE-specific uplink-downlink configuration 620 for flexible slots or slots 621 and 622 including flexible symbols may be semi-statically indicated through UE-specific configuration information through dedicated higher layer signaling. Each slot/symbol may be configured as uplink or downlink by the number 623 or 625 of contiguous downlink symbols from the start symbol of the slot 621 or 622 and the number 624 or 626 of contiguous uplink symbols from the end of the slot or the entire slot may be configured as downlink or uplink.
Finally, the uplink-downlink configuration 630 for each UE group for the symbols not indicated as downlink or uplink through system information and UE-specific configuration information may be dynamically configured as downlink or uplink by the slot format indicator (SFI) 631 or 632 included in the downlink control channel. The slot format indicator 1631 or 632 may indicate one index selected from a preconfigured table showing uplink-downlink configurations of 14 symbols in one slot. The table may be as shown in Table 21 below, for example.
Additional coverage extension technology has been adopted for the 5G wireless communication service, as compared with the LTE communication service, but actual coverage of the 5G wireless communication service may use the time division duplex (TDD) technique appropriate for services which generally put more weight on downlink traffic. Further, as the center frequency increases to extend the frequency band, the coverage of the base station and the UE reduces. Thus, coverage enhancement is a key requirement for the 5G wireless communication service. In particular, overall, the UE transmit power is lower than the base station transmit power and, in the time domain, downlink takes a more proportion than uplink to support services that puts more weight on downlink traffic, so that coverage enhancement of uplink channel is a core requirement for the 5G wireless communication service.
The uplink channel coverage of the base station and UE may be physically enhanced by increasing the time resources of uplink channel, reducing the center frequency, or raising the UE transmit power. However, increasing time resources and changing frequency may be limited due to limitations on the frequency band predetermined by each network operator. Raising the UE transmit power may be limited due to the fact that the maximum transmit power is fixed by the standard to reduce interference.
Thus, to enhance base station and UE coverage, it is possible to divide the uplink resource and downlink resources in the time domain depending on the uplink and downlink traffic proportions like in the TDD system or to divide the uplink resource and downlink resource in the frequency domain like in the FDD system. In the disclosure, the system that may flexibly divide the uplink resource and downlink resource in the time domain and/or frequency domain may be referred to as an XDD system, flexible TDD system, hybrid TDD system, TDD-FDD system, hybrid TDD-FDD system, subband full duplex system, or dynamic TDD system and, for convenience of description, it is referred to as an XDD system below. In XDD, ‘X’ may mean time and/or frequency.
Referring to
Referring to
Referring to
Downlink transmission from the base station to the UE may be performed in the regions 810, 820, and 830 configured as the downlink resource 800, and uplink transmission from the UE to the base station may be performed in the regions 811, 821, and 831 configured as the uplink resource 801. In this case, when the downlink resource 800 and the uplink resource 801 at least partially overlap each other in the time and frequency domains, downlink and uplink transmission/reception of the base station or the UE in the same time and frequency resource may simultaneously occur (e.g., during at least one same OFDM symbol).
Referring to
The TX baseband processing block 910 may perform digital processing on the TX signal.
The digital pre-distortion block 911 may perform pre-distortion on the digital TX signal.
The DAC 912 may convert the digital signal into an analog signal.
The pre-driver 913 may perform gradual power amplification on the analog TX signal.
The power amplifier 914 may perform power amplification on the analog TX signal.
The TX antenna 915 may transmit the power-amplified signal 901.
Referring to
The RX antenna 924 may receive the RF band signal 902.
The low noise amplifier 923 may amplify the power the analog RX signal while minimizing noise amplification.
The ADC 922 may convert the analog signal into a digital signal.
The SIC block 921 may perform interference cancellation on the digital signal.
The RX baseband processing block 920 may perform digital processing on the interference-canceled signal.
A power amplifier (PA) coupler 916 and a coefficient update block 917 may be present for additional signal processing between the TX end and the RX end. Each of the blocks may perform the following roles.
The PA coupler 916 may detect the waveform of the analog TX signal which has undergone the power amplifier 914 to be observed at the RX end. The detected signal may be input to the ADC 922 by a switch 916a.
The coefficient update block 917 may update various coefficients necessary for digital signal processing at the TX end and RX end. The computed coefficients may be used to configure parameters necessary at the DPD 911 of the TX end and the SIC 921 of the RX end.
The transceiver structure shown in
When the base station simultaneously performs downlink transmission and uplink reception, the downlink signal transmitted by the TX end of the base station may be received by the RX end of the base station so that interference (i.e., self-interference) may occur between the downlink signal transmitted from the base station and the uplink signal originally intended to be received at the RX end of the base station. Similarly, when the UE simultaneously performs downlink reception and uplink transmission, the uplink signal transmitted from the TX end of the UE may be received by the RX end of the UE so that interference (i.e., self-interference) may occur between the uplink signal transmitted from the UE and the downlink signal originally intended to be received at the RX end of the UE. As such, interference between links in different directions, i.e., downlink signal and uplink signal in the base station and the UE may be referred to as cross-link interference.
The self-interference between the TX signal (or downlink/uplink signal) and the RX signal (or uplink/downlink signal) may occur in the system where transmission and reception are simultaneously performed. As an example, self-interference may occur in the above-described XDD system.
Referring to
As an example, as shown, some resource area 1006 in the uplink band 1003 adjacent to the downlink band 1002 may be significantly influenced by the ACL 1005. Some resource area 1007 in the uplink band 1003 relatively far away from the uplink band 1002 may be less influenced by the interference by the ACL 1005. In other words, the uplink band 1003 may have a resource area 1006 which is relatively more influenced by the interference and a resource area 1007 which is relatively less influenced by the interference. A guard band 1004 may be inserted between the downlink bandwidth 1002 and the uplink bandwidth 1003 for the purpose of reducing performance deterioration.
As the size of the guard band 1004 increase, the influence by the interference due to the ACL 1005 between the downlink bandwidth 1002 and the uplink bandwidth 1003 may advantageously reduce. However, as the size of the guard band 1004 increases, the resources available for transmission/reception reduce, lowering resource efficiency. In contrast, as the size of the guard band 1004 reduces, the amount of resources available for transmission/reception may increase. Thus, resource efficiency may be increased, but the influence by the interference due to the ACL 1005 may increase between the downlink bandwidth 1002 and the uplink bandwidth 1003. Accordingly, it is critical to determine a proper size of the guard band 1004 considering the tradeoff.
A need may exist for a special type of transceiver structure for effectively processing self-interference between TX signal (or downlink/uplink signal) and RX signal (or uplink/downlink signal). For example, the transceiver structure shown in
As an embodiment, the DPD block 911 of the TX end may pre-distort the TX signal in the digital domain, thereby minimizing the power leakage (e.g., the ACL 1005 of
In the disclosure, a resource configuration for uplink and downlink transmission/reception in the time and frequency domains is described, and embodiments for changing to different uplink and downlink configurations in a specific uplink and downlink configuration are provided.
Higher layer signaling below may include at least one or a combination of one or more of the following signaling.
Further, L1 signaling may include at least one or a combination of one or more of the following physical layer channels or signaling methods.
Described here is signaling of cell-specific configuration information for uplink and/or downlink resource configuration in the time domain and frequency domain in the XDD system. The UE may be configured with different frequency domain resources for uplink and downlink in the same time domain resource through resource configuration for uplink or downlink described below. Accordingly, the resource where the UE is capable of uplink transmission or downlink reception may increase, and uplink coverage of the UE and base station may be enhanced. The resource configuration for uplink or downlink transmission/reception is referred to below as uplink-downlink configuration for convenience of description.
In the XDD system, the UE may be allocated resources for transmission/reception, separately for uplink and downlink in the frequency domain as well as time domain. Accordingly, the resources for uplink or downlink transmission/reception may be configured for both the time domain and the frequency domain, rather than configured only for the time domain like the TDD system. The base station may configure a guard band to the UE through resource configuration for uplink or downlink transmission/reception in the time domain and frequency domain, thereby suppressing influence by interference due to the out-of-band (OOB) emissions caused as the frequency bands of the uplink and downlink resources are relatively close to each other as compared with FDD. Further, the UE may determine what frequency band the UE is actually scheduled and transmitted/received in although the uplink BWP and the downlink BWP have the same center frequency through resource configuration for uplink or downlink transmission/reception in the time domain and frequency domain.
The following methods may be considered as the resource configuration for uplink or downlink transmission/reception in the time domain and frequency domain in the XDD system.
To provide the resource configuration for uplink or downlink transmission/reception in the time domain and frequency domain to the UE, the base station may divide the entire frequency band into n frequency bands and transmit information indicating the uplink-downlink configuration (hereinafter, referred to as uplink-downlink configuration information) in the time domain to the UE in each frequency band. Each of the n frequency bands may be constituted of a set or group of contiguous resource blocks (RBs) and this may be referred to as a resource block set (RBS) or resource block group (RBG). For convenience of description, it is denoted as the RBS in the disclosure.
The uplink-downlink configuration information for each frequency band may include uplink-downlink pattern information and reference subcarrier spacing information. The uplink-downlink pattern information may include the periodicity to which the pattern is applied in the time domain, the number of contiguous downlink slots from the start point of the pattern, the number of symbols of the next slot, and the number of contiguous uplink slots from the end of the pattern and the number of symbols of the immediately prior slot. In this case, slots and symbols not indicated by uplink or downlink may be determined as flexible slots/symbols.
Referring to
As an example, the pattern period 1115 of RBS1 1110 may be set to five slots (or 5 ms for the subcarrier spacing of 15 kHz), the number 1111 of contiguous downlink slots from the start point of the pattern may be set to three, the number 1113 of downlink symbols of the next slot to four, the number 1113 of contiguous uplink slots from the end of the pattern to one, and the number 1114 of the uplink symbols of the immediately prior slot to three. The uplink-downlink configurations 1121, 1122, 1123, and 1124 of RBS2 1120 may be the same as those of RBS1 1110.
The uplink-downlink pattern period 1135 of RBS3 1130 may be set to two slots (or 2 ms for the subcarrier spacing of 15 kHz), the number of contiguous downlink slots from the start point of the pattern may be set to zero, the number 1132 of downlink symbols of the next slot to six, the number 1133 of contiguous uplink slots from the end of the pattern to one, and the number 1134 of the uplink symbols of the immediately prior slot to four. The uplink-downlink pattern period 1145 of RBS4 1140 may be set to two slots (or 2 ms for the subcarrier spacing of 15 kHz), the number of contiguous downlink slots from the start point of the pattern may be set to zero, the number of downlink symbols of the next slot to zero, the number 1133 of contiguous uplink slots from the end of the pattern to two, and the number 1134 of the uplink symbols of the immediately prior slot to zero.
Since uplink-downlink configurations are configured in each RBS in the limited overhead for uplink-downlink configuration, an uplink or downlink resource may be flexibly configured relatively in the time domain.
For uplink-downlink configuration in the time domain and frequency domain to the UE, the base station may divide the entire frequency band into n frequency bands and transmit information indicating the uplink-downlink configuration (hereinafter, referred to as uplink-downlink configuration information) in the frequency domain to the UE in each frequency band. The uplink-downlink configuration information for each pattern may include uplink-downlink pattern information and reference subcarrier spacing information. The uplink-downlink pattern information may include the number of slot(s)/symbol(s) in the time domain having the same pattern, the number of contiguous downlink RBSs from the start point of the entire frequency band, the number of downlink RBs in the next RBS, the number of contiguous uplink RBSs from the end of the entire frequency band, and the number of uplink RBs of the prior RBS. In this case, the RBS and RB not indicated as uplink and downlink may be determined as flexible RBS/RB.
Referring to
As an example, the period 1211 of the first pattern 1210 may be set to four slots (or 4 ms for the subcarrier spacing of 15 kHz), the number 1212 of contiguous downlink RBSs from the start point of the entire frequency band may be set to two, the number 1213 of downlink RBs of the next RBS to 12, the number 1214 of contiguous uplink RBSs from the end of the entire frequency band to one, and the number 1215 of the uplink RBs of the prior RBS to four. The period 1221 of the second pattern 1220 may be set to one slot (or 1 ms for the subcarrier spacing of 15 kHz), and the number 1224 of contiguous uplink RBSs from the end of the entire frequency band may be set to four.
When the first pattern 1210 and the second pattern 1220 are configured by the base station, the two patterns 1210 may be repeatedly applied with their respective periods 1211 and 1220 in the time domain.
Since the uplink-downlink resources are configured in the frequency domain with the time domain period for each pattern in the limited overhead for uplink-downlink configuration, uplink or downlink resources may be configured relatively more flexibly in the frequency domain than in the time domain. In this case, a guard band may be efficiently configured as a scheme for reducing interference with the uplink channel or signal reception by the out-of-band emission caused when the base station transmits a downlink channel or signal in the downlink resource in the XDD system.
The XDD system requires that the entire frequency resource be divided into specific units for application of the uplink-downlink configuration, rather than simply dividing uplink and downlink resources only in the time domain as in the TDD system. As an example, when the entire frequency band is 100 MHz, and the subcarrier spacing is 30 kHz, the entire frequency band may be constituted of 273 RBs. In this case, significant overhead is required to configure each of the 273 RBs as an uplink or downlink resource.
Thus, the XDD system may consider the following methods for dividing the frequency band to which the time domain and frequency domain uplink-downlink configurations are applied.
The RBs of the entire frequency band may be constituted of n groups each including a specific number of RBs. The number of RBs per group may be indicated through the uplink-downlink configuration or be set to a value pre-agreed on between the base station and the UE. As an example, when the subcarrier spacing (SCS) is 30 kHz, and the entire frequency band is 100 MHz, the total number of RBs is 273. The number of RBs in each group may be included in the uplink-downlink configuration to be indicated, or be pre-agreed on between the base station and the UE. If the number of RBs in each group is set to 24, n=[total number of RBs/number of RBs configured per group]=[273/24]=12 groups in total may be configured. The number of RBs in each group may be efficiently determined to reduce the overhead for the uplink-downlink configuration of the frequency domain.
The setting of the number of RBs per group to configure the RBs of the frequency band into n groups of a specific number of RBs is not limited to the value indicated by signaling of the uplink-downlink configuration or pre-agreed on but may also be indicated through at least one of the system information block, UE-specific configuration information through dedicated higher layer signaling, media access control (MAC) control element (CE), or L1 signaling (i.e., downlink control information).
The entire frequency band may be constituted of n groups with a specific frequency band. The frequency bandwidth of the specific frequency band belonging to each group may be indicated through the uplink-downlink configuration or determined to be a value pre-agreed on between the base station and the UE. As an example, if the frequency band per group in the entire frequency band of 100 MHz is indicated as 20 MHz by the uplink-downlink configuration or is set to 20 MHz according to a pre-configuration pre-agreed on between the base station and the UE, n=[total frequency bands/frequency bands configured per group]=[100/20]=5 groups in total may be configured. The frequency bandwidth in each group may be efficiently determined to reduce the overhead for the uplink-downlink configuration of the frequency domain.
The setting of the frequency bandwidth per group to configure the entire frequency band into n groups of a specific frequency bandwidth is not limited to the value indicated by signaling of the uplink-downlink configuration or pre-agreed on but may also be indicated through at least one of the pre-agreed system information block, UE-specific configuration information through dedicated higher layer signaling, MAC CE, or L1 signaling (e.g., downlink control information).
The entire frequency band may be constituted of two groups divided by a guard band. The frequency band of the guard band may be indicated through the uplink-downlink configuration, and two groups respectively including a lower frequency band and a higher frequency band than the guard band may be configured around the guard band. As an example, if 50 carrier resource blocks (CRBs) are configured starting from the 100th CRB with respect to reference point A which means the frequency point as the guard band in the entire frequency band of 100 MHz, reference point A to the 99th CRB which are a frequency band lower than the guard band may become the first group, and the 150th CRB to the last CRB which are a higher frequency band than the guard band may become the second group.
The two groups may be efficiently determined to reduce the overhead for the uplink-downlink configuration of the frequency domain. It is very difficult to implement the base station so that the downlink resource and the uplink resource are non-contiguously allocated at the same time point, and interference due to the OOB may occur between the uplink and the downlink. Therefore, if the downlink or uplink should be configured contiguously all the time, the two groups may be efficiently divided by the guard band configured between the downlink and the uplink. The UE may receive the start position (e.g., CRB number) and size (e.g., number of CRBs) of the guard band from the base station through the uplink-downlink configuration and divide the entire frequency band into two groups with respect to the guard band.
The setting of the guard band to configure the entire frequency band into two groups is not limited to the value indicated by signaling of the uplink-downlink configuration but may also be indicated through at least one of a pre-agreed value, the system information block, UE-specific configuration information through dedicated higher layer signaling, MAC CE, or L1 signaling (e.g., downlink control information).
According to an embodiment of the disclosure, uplink and downlink resources may be flexibly configured in the time and frequency domains. Accordingly, one time and frequency resource may be configured as uplink or downlink. Hereinafter, in the disclosure, configuring each time and frequency resource as uplink or downlink is referred to as “uplink-downlink configuration (UL-DL configuration)”. The uplink-downlink configuration may include any one of a downlink symbol, an uplink symbol, and a flexible symbol configuration. For example, one uplink-downlink configuration may correspond to one or more DL-UL patterns indicated by the uplink-downlink configuration information exemplified in
According to an embodiment, the uplink-downlink configuration may be changed to static, semi-static, or dynamic. The base station may transmit or indicate the uplink-downlink configuration information through at least one of [combination of higher layer signaling or L1 signaling] or [combination of higher layer signaling and L1 signaling]. As an example, the base station may set the uplink-downlink configuration through higher layer signaling. For example, the base station may set one or more uplink-downlink configurations through higher layer signaling and activate one of the uplink-downlink configurations through higher layer signaling (e.g., RRC signaling or MAC CE) or L1 signaling. If the UE receives or is indicated for the uplink-downlink configuration from the base station, reception may be expected for the resource configured as downlink and transmission may be expected for the resource configured as uplink. Various signaling methods of uplink-downlink configuration are as described above.
According to an embodiment of the disclosure, the uplink-downlink configuration may be changed based on L1 signaling (e.g., DCI). The base station may transmit a DCI format including a change indicator to change uplink-downlink configuration A into uplink-downlink configuration B (where B differs from A) to the UE through the PDCCH. The UE may receive the DCI format including the change indicator to change the uplink-downlink configuration from the base station and change the current uplink-downlink configuration A into uplink-downlink configuration B based on the change indicator in the DCI format. After the change, uplink-downlink configuration B may be explicitly or implicitly indicated by the change indicator or be pre-agreed on between the base station and the UE.
According to an embodiment of the disclosure, a table constituted of a plurality of uplink-downlink configurations may be configured from the base station to the UE through higher layer signaling or pre-defined in the base station and the UE. For example, an “uplink-downlink configuration table” constituted of N uplink-downlink configurations {uplink-downlink configuration #1, uplink-downlink configuration #2, uplink-downlink configuration #3, ..., uplink-downlink configuration #N} may be pre-defined or be transmitted from the base station to the UE through higher layer signaling. The base station may transmit the change indicator indicating uplink-downlink configuration#X to activate in the uplink-downlink configuration table to the UE through L1 signaling (e.g., DCI format). The UE may activate uplink-downlink configuration#X indicated by the change indicator in the L1 signaling (e.g., DCI format) received from the base station based on the uplink-downlink configuration table.
According to an embodiment of the disclosure, when the uplink-downlink configuration is changed, a change delay time Tdelay may be considered before using the changed uplink-downlink configuration. As described above, the parameters for the blocks in the transceiver to effectively process interference between downlink and uplink may be configured according to the uplink-downlink transmission resource pattern, so that a predetermined delay time Tdelay may be used to change the transceiver parameters according to the change in uplink-downlink configuration.
To change uplink-downlink configuration A 1303 into uplink-downlink configuration B 1304, a change delay time corresponding to Tdelay1320 may be required in the base station and the UE. In other words, the base station may transmit the change indicator 1310 in slot n to change the uplink-downlink configuration and perform uplink and downlink operations based on the changed uplink-downlink configuration from slots after slot n+Tdelay. Likewise, upon receiving the change indicator in slot n from the base station, the UE may perform uplink and downlink operations based on the changed uplink-downlink configuration from slots after slot n+Tdelay.
In the illustrated example, the change indicator 1310 to indicate to change into uplink-downlink configuration B 1304 in slot 3 may be transmitted. In an embodiment, Tdelay1320 may be pre-agreed on as a specific value, e.g., “2,” between the base station and the UE. The base station may start transmission/reception operations according to uplink-downlink configuration B 1304 in slot 6, which is two slots after slot 3. Likewise, upon receiving the change indicator 1310 in slot 3, the UE expects transmission/reception operations according to uplink-downlink configuration B 1304 from slot 6.
According to an embodiment of the disclosure, the change delay time Tdelay1320 may be conditionally applied when the “change delay condition” pre-agreed on between the base station and the UE is met. In an embodiment, when the change delay condition is met, the base station and the UE may regard Tdelay1320 as a value larger than 0, as pre-agreed on, and when the change delay condition is not met, the base station and the UE may regard Tdelay1320 as 0. The change delay condition may include at least one of, e.g., the following conditions or a combination of at least one or more conditions.
When the uplink-downlink direction in a specific frequency domain resource is changed by uplink-downlink configuration A before change and uplink-downlink configuration B after change, a change delay time Tdelay larger than 0 may be required. For example, in the example of
When the guard band is varied in uplink-downlink configuration A before change and uplink-downlink configuration B after change (e.g., when the guard band is changed in position or size), a change delay time Tdelay larger than 0 may be required. For example, in the example of
The guard band in each uplink-downlink configuration has a size and position required considering interference between uplink and downlink. In other words, the configuration for the guard band may also differ depending on the uplink-downlink configuration, and a change in guard band may mean a change in the interference context between uplink and downlink. Accordingly, if the guard band is changed by the change in uplink-downlink configuration, the uplink-downlink interference state may be rendered to differ from before. Thus, the base station or UE requires an additional time to set the parameters of the transceiver to the optimal values and may determine that a change delay time Tdelay to ensure the additional time is required.
When uplink-downlink configuration A before change corresponds to a specific uplink-downlink configuration X, a change delay time Tdelay1320 larger than 0 may be required. In an embodiment, the specific uplink-downlink configuration X may be pre-defined, explicitly preset to the UE by the base station through higher layer signaling, or implicitly determined by the system parameter. In an embodiment, one or more specific uplink-downlink configurations X may be defined. In an embodiment, an uplink-downlink configuration set X including a plurality of specific uplink-downlink configurations may be configured. When uplink-downlink configuration A before change is included in the uplink-downlink configuration set X, the base station and the UE may determine that a change delay time is required.
When uplink-downlink configuration B after change corresponds to a specific uplink-downlink configuration Y, a change delay time Tdelay1320 larger than 0 may be required. In an embodiment, the specific uplink-downlink configuration Y may be pre-defined, explicitly preset to the UE by the base station through higher layer signaling, or implicitly determined by the system parameter. In an embodiment, one or more specific uplink-downlink configurations Y may be defined. In an embodiment, an uplink-downlink configuration set Y including a plurality of specific uplink-downlink configurations may be configured. When uplink-downlink configuration B after change is included in the uplink-downlink configuration set Y, the base station and the UE may determine that a change delay time is required.
When uplink-downlink configuration A before change corresponds to the specific uplink-downlink configuration X, and uplink-downlink configuration B after change corresponds to the specific uplink-downlink configuration Y, a change delay time Tdelay1320 may be required. In an embodiment, the specific uplink-downlink configuration X and the specific uplink-downlink configuration Y may be pre-defined, explicitly preset to the UE by the base station through higher layer signaling, or implicitly determined by the system parameter. In an embodiment, there may be one or more specific uplink-downlink configurations X and one or more specific uplink-downlink configurations Y. In an embodiment, an uplink-downlink configuration set X including a plurality of uplink-downlink configurations and an uplink-downlink configuration set Y including a plurality of uplink-downlink configurations may be configured. When uplink-downlink configuration A before change is included in the uplink-downlink configuration set X, and uplink-downlink configuration B after change is included in the uplink-downlink configuration set Y, the base station and the UE may determine that a change delay time is required.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay1320 may always be used when a change in uplink-downlink configuration occurs. In other words, the base station and the UE may delay the change in uplink-downlink configuration always based on the change delay time Tdelay regardless of the above-described change delay conditions.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be predefined as a fixed value larger than 0. The base station and the UE may delay the change in uplink-downlink configuration based on the pre-defined Tdelay value.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be explicitly set or notified through at least one higher layer signaling from the base station to the UE. The base station may delay the change in uplink-downlink configuration based on the set Tdelay value, and the UE may delay the change in uplink-downlink configuration based on the set Tdelay value notified of by the base station.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be notified of from the UE to the base station through UE capability signaling. The base station and the UE may delay the change in uplink-downlink configuration based on the Tdelay value notified of through UE capability signaling.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be defined to differ depending on the subcarrier spacing value. In other words, for the subcarrier spacing i, Tdelay,i may be defined. For example, when the subcarrier spacing is 15 kHz, Tdelay,0 may be used. When the subcarrier spacing is 30 kHz, Tdeiay,1 may be used. When the subcarrier spacing is 60 kHz, Tdelay,2 may be used. When the subcarrier spacing is 120 kHz, Tdelay,3 may be used. The change delay time for each subcarrier spacing may be predetermined as a fixed value or be notified of by signaling between the base station and the UE.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be defined to be the same regardless of the subcarrier spacing value.
According to an embodiment of the disclosure, the uplink-downlink change delay time Tdelay may be defined to differ depending on the uplink-downlink configurations before and/or after change. For example, upon changing from uplink-downlink configuration A1 to uplink-downlink configuration B 1, the change delay time Tdelay,1 may be used. For example, upon changing from uplink-downlink configuration A2 to uplink-downlink configuration B2, the change delay time Tdelay,2 may be used.
According to an embodiment of the disclosure, the base station may refrain from transmission or reception for the UE during a predetermined change delay time Tdelay after the uplink-downlink configuration is changed. For example, the base station may delay transmission/reception of the PDCCH/PDSCH/PUCCH/PUSCH for the UE, at least, during the change delay time. For example, the base station may not schedule transmission or reception of a channel related to the UE during the change delay time. The UE may not expect transmission or reception during the uplink-downlink change delay time Tdelay. When the UE receives the change indicator for the uplink-downlink configuration in slot n, and an uplink-downlink change delay time is required, the UE may not expect transmission or reception from slot n until slot n+Tdelay.
According to an embodiment of the disclosure, the uplink-downlink configuration change indicator may be transmitted from the base station to the UE through at least one of the common DCI (or DCI format monitored in the common search space), the group-common DCI (or DCI format monitored in type-3 common search space), the UE-specific DCI (or DCI format monitored in the UE-specific search space) or a DCI format including scheduling or a DCI format not including scheduling.
According to an embodiment of the disclosure, the uplink-downlink configuration change indicator may include uplink-downlink configuration information about one or more slots. In other words, the base station may transmit a change indicator indicating a new uplink-downlink configuration for one or more slots to the UE, and the UE may receive the change indicator and apply the new uplink-downlink configuration to the one or more slots. The UE may identify the one or more slots to which the new uplink-downlink configuration is applied according to the signaling from the base station or a pre-agreed rule.
Referring to
If the change delay condition is determined to be met, in step 1415, the base station may apply the new uplink-downlink configuration according to the change indicator considering a pre-agreed change delay time. In an embodiment, the base station may schedule not to perform transmission or reception for the UE during the change delay time after the change indicator is transmitted. After the delay for the change delay time, the base station may perform transmission or reception for the UE according to the new uplink-downlink configuration.
If the change delay condition is determined not to be met, in step 1420, the base station may immediately apply the new uplink-downlink configuration after transmission of the change indicator without the change delay time. In an embodiment, the base station may start transmission/reception according to the new uplink-downlink configuration in the next slot after the slot when the change indicator is transmitted.
Referring to
If the change delay condition is determined to be met, in step 1515, the UE may apply the new uplink-downlink configuration according to the change indicator considering a pre-agreed change delay time. In an embodiment, the UE may not expect transmission or reception during the change delay time after the change indicator is transmitted. If the change delay condition is determined not to be met, in step 1520, the UE may immediately apply the new uplink-downlink configuration after transmission of the change indicator without the change delay time. In an embodiment, the UE may expect transmission/reception according to the new uplink-downlink configuration in the next slot after the slot when the change indicator is received.
Referring to
The transceiver 1605 may transmit and receive signals to/from a base station. The signals may include control information and data. To that end, the transceiver 1605 may include an RF transmitter for frequency-up converting and amplifying signals transmitted and an RF receiver for low-noise amplifying signals received and frequency-down converting the frequency of the received signals. The transceiver 1605 may receive signals via a radio channel, provide the signals to the processor 1600, and transmit signals transferred from the processor 1600 via a radio channel. As an example, the transceiver 1605 may have the above-described configuration of
The memory 1610 may store programs and data necessary for the operation of the UE. The memory 1610 may store control information or data that is included in the signal transmitted/received by the UE. The memory 1610 may include a storage medium, such as ROM, RAM, hard disk, CD-ROM, or DVD, or a combination of storage media. Further, the memory 1610 may include a plurality of memories. The memory 1610 may store a program for executing an operation for changing the uplink-downlink configuration of the UE.
The processor 1600 may control a series of processes for the UE to be able to operate according to at least one of the above-described embodiments. The processor 1600 may execute the program stored in the memory 1610 to control the transceiver 1605 to receive at least one of uplink-downlink configuration information, an uplink-downlink change indicator, or a set value of a change delay time from the base station and perform transmission and reception operations according to an uplink-downlink configuration determined based on the received information.
Referring to
The transceiver 1705 may transmit and receive signals to/from a UE. The signals may include control information and data. To that end, the transceiver 1705 may include an RF transmitter for frequency-up converting and amplifying signals transmitted and an RF receiver for low-noise amplifying signals received and frequency-down converting the frequency of the received signals. The transceiver 1705 may receive signals via a radio channel, provide the signals to the processor 1700, and transmit signals transferred from the processor 1700 via a radio channel. As an example, the transceiver 1705 may have the above-described configuration of
The memory 1710 may store programs and data necessary for the operation of the base station. Further, the memory 1710 may store control information or data that is included in the signal transmitted/received by the base station. The memory 1710 may include a storage medium, such as ROM, RAM, hard disk, CD-ROM, or DVD, or a combination of storage media. Further, the memory 1710 may include a plurality of memories. The memory 1710 may store a program for executing an operation for changing the uplink-downlink configuration of the base station.
The processor 1700 may control a series of processes for the base station to be able to operate according to at least one of the above-described embodiments. The processor 1700 may execute the program stored in the memory 1710 to control the transceiver 1705 to transmit at least one of uplink-downlink configuration information, an uplink-downlink change indicator, or a set value of a change delay time to the UE and perform transmission and reception operations according to an uplink-downlink configuration of the UE, determined based on the information.
The methods according to the embodiments descried in the specification or claims of the disclosure may be implemented in hardware, software, or a combination of hardware and software.
When implemented in software, there may be provided a computer readable storage medium or computer program product storing one or more programs (software modules). One or more programs stored in the computer readable storage medium or computer program product are configured to be executed by one or more processors in an electronic device. One or more programs include instructions that enable the electronic device to execute methods according to the embodiments described in the specification or claims of the disclosure.
The programs (software modules or software) may be stored in random access memories, non-volatile memories including flash memories, read-only memories (ROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic disc storage devices, compact-disc ROMs, digital versatile discs (DVDs), or other types of optical storage devices, or magnetic cassettes. Or, the programs may be stored in a memory constituted of a combination of all or some thereof. As each constituting memory, multiple ones may be included.
The programs may be stored in attachable storage devices that may be accessed via a communication network, such as the Internet, Intranet, local area network (LAN), wide area network (WLAN), or storage area network (SAN) or a communication network configured of a combination thereof. The storage device may connect to the device that performs embodiments of the disclosure via an external port. A separate storage device over the communication network may be connected to the device that performs embodiments of the disclosure.
In the above-described specific embodiments, the components included in the disclosure are represented in singular or plural forms depending on specific embodiments proposed. However, the singular or plural forms are selected to be adequate for contexts suggested for ease of description, and the disclosure is not limited to singular or plural components. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The embodiments herein are provided merely for better understanding of the present invention, and the present invention should not be limited thereto or thereby. In other words, it is apparent to one of ordinary skill in the art that various changes may be made thereto without departing from the scope of the present invention. Further, the embodiments may be practiced in combination. For example, the base station and the UE may be operated in a combination of parts of an embodiment and another embodiment. Embodiments of the disclosure may be applied to other communication systems, and various modifications may be made thereto based on the technical spirit of embodiments. For example, embodiments may also be applied to LTE systems, 5G or NR systems.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0086910 | Jul 2020 | KR | national |
This application is a U.S. National Stage application under 35 U.S.C. § 371 of an International application number PCT/KR2021/007903, filed on Jun. 23, 2021, which is based on and claims priority of a Korean patent application number 10-2020-0086910, filed on Jul. 14, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2021/007903 | 6/23/2021 | WO |
