Method performed by terminal or network in wireless communication system, and apparatus therefor

Abstract

A method performed by a terminal according to at least one of embodiments disclosed in the present specification comprises: receiving configuration information for codebook subset restriction (CBSR) through higher layer signaling; determining, on the basis of the configuration information for the CBSR, a precoder subset within a codebook including a plurality of precoders; receiving a channel state information-reference signal (CSI-RS); and transmitting a CSI report on the basis of the precoder subset and the CSI-RS, wherein the CSI-RS is transmitted through more than 32 antenna ports, the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain and (ii) information about the X1 and the X2, and the number M of precoder components associated with respective bits of the bitmap may be determined on the basis of the X1 and the X2.

Description

Method performed by a terminal or network in a wireless communication system and device therefor

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and device for transmitting or receiving an uplink / downlink wireless signal by a terminal or a network in a wireless communication system.

[0002] Wireless communication systems are widely deployed to provide various types of communication services, such as voice and data. Typically, wireless communication systems are multiple access systems that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power). Examples of multiple access systems include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-carrier frequency division multiple access (SC-FDMA).

[0003] NR Rel.15~18 supported up to 32-Tx port CSI-RS transmission. To improve system throughput in NR Rel.19, discussions are underway to expand to up to 128 port CSI-RS.

[0004] The technical task to be achieved in the present disclosure is to provide a method and device for efficiently performing a wireless signal transmission and reception process. As an example, a codebook subset restriction (CBSR) technique is provided for CSI reporting for up to 128 port CSI-RSs.

[0005] In addition to the technical challenges described above, other technical challenges can be inferred from the description below.

[0006] According to one aspect, a method performed by a terminal includes receiving configuration information for a codebook subset restriction (CBSR) through upper layer signaling; determining a precoder subset within a codebook including a plurality of precoders based on the configuration information for the CBSR; receiving a channel state information-reference signal (CSI-RS); and transmitting a CSI report based on the precoder subset and the CSI-RS, wherein the CSI-RS is transmitted through more than 32 antenna ports, and wherein the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain and (ii) information about the X1 and the X2, and a number M of precoder components associated with each bit of the bitmap can be determined based on the X1 and the X2.

[0007] The above M is determined based on N1*O1 / X1 and N2*O2 / X2, where the N1 and the O1 may be the number of antennas and the first oversampling factor in the first domain, respectively, and the N2 and the O2 may be the number of antennas and the second oversampling factor in the second domain, respectively.

[0008] The above M can be (N1*O1 / X1) * (N2*O2 / X2).

[0009] Multiple groups can be set based on the above X1 and X2.

[0010] Each group can contain M precoder components.

[0011] Whether CBSR is applied to each group can be determined based on whether the value of each bit of the above bitmap is 0 or 1.

[0012] The precoder subset can be determined based on at least one group to which the CBSR does not apply.

[0013] The above bitmap may contain X1*X2 bits.

[0014] The above precoder components may be SD (spatial domain) basis vectors.

[0015] The above codebook may be a Type I codebook or a Type II codebook.

[0016] The above CSI-RS can be transmitted through 48, 64 or 128 antenna ports.

[0017] According to another aspect of the present disclosure, a non-transitory computer-readable recording medium having recorded thereon a program for performing the method described above may be provided.

[0018] According to another aspect of the present disclosure, a device comprises a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations of the processor include receiving configuration information for a codebook subset restriction (CBSR) via higher layer signaling; determining a precoder subset within a codebook including a plurality of precoders based on the configuration information for the CBSR; receiving a channel state information-reference signal (CSI-RS); and transmitting a CSI report based on the precoder subset and the CSI-RS, wherein the CSI-RS is transmitted through more than 32 antenna ports, and wherein the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain and (ii) information about the X1 and the X2, wherein the number M of precoder components associated with each bit of the bitmap can be determined based on the X1 and the X2.

[0019] The above device may further include a transceiver.

[0020] The above device may be a terminal in a wireless communication system.

[0021] The above device may be a processing device configured to control a terminal in a wireless communication system.

[0022] According to another aspect of the present disclosure, a method performed by a base station includes determining a precoder subset within a codebook including a plurality of precoders; transmitting, based on the determined precoder subset, configuration information for a codebook subset restriction (CBSR) to a terminal via upper layer signaling; transmitting a channel state information-reference signal (CSI-RS) to the terminal; and receiving a CSI report from the terminal, wherein the CSI-RS is transmitted through more than 32 antenna ports, and the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain and (ii) information about the X1 and the X2, wherein the number M of precoder components associated with each bit of the bitmap can be determined based on the X1 and the X2.

[0023] According to another aspect of the present disclosure, a base station comprises a memory configured to store instructions; and a processor configured to perform operations by executing the instructions, wherein the operations of the processor include determining a precoder subset within a codebook including a plurality of precoders; transmitting, based on the determined precoder subset, configuration information for a codebook subset restriction (CBSR) to a terminal via upper layer signaling; transmitting a channel state information-reference signal (CSI-RS) to the terminal; and receiving a CSI report from the terminal, wherein the CSI-RS is transmitted through more than 32 antenna ports, and the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain and (ii) information for the X1 and the X2, wherein the number M of precoder components associated with each bit of the bitmap can be determined based on the X1 and the X2.

[0024] According to the present disclosure, wireless signal transmission and reception can be efficiently performed in a wireless communication system. For example, a codebook subset restriction (CBSR) technique is provided for CSI reporting for up to 128 port CSI-RSs, thereby reducing interference with adjacent cells and reducing CSI feedback overhead.

[0025] In addition to the technical effects described above, other technical effects can be inferred from the description below.

[0026] Figure 1 illustrates physical channels used in a 3GPP system, which is an example of a wireless communication system, and a general signal transmission method using the channels.

[0027] Figure 2 illustrates the structure of a radio frame.

[0028] Figure 3 illustrates a resource grid of slots.

[0029] Figure 4 illustrates an example of physical channels being mapped within a slot.

[0030] Figure 5 illustrates the PDSCH and ACK / NACK transmission process.

[0031] Figure 6 illustrates a PUSCH transmission process.

[0032] Figure 7 shows an example of a CSI-related procedure.

[0033] Figure 8 illustrates the antenna configuration and the port configuration within the panel.

[0034] Figure 9 is a diagram illustrating the structure of an enhanced Type II codebook.

[0035] Fig. 10 illustrates an example of a bitmap for CBSR according to method 1 of proposal 1.

[0036] Fig. 11 illustrates another example of a bitmap for CBSR according to method 1 of proposal 1.

[0037] Figure 12 illustrates an example of a bitmap for CBSR according to method 2 of proposal 1.

[0038] Figure 13 illustrates another example of a bitmap for CBSR according to method 2 of proposal 1.

[0039] Figures 14 to 16 illustrate examples of CBSR for the case where the size of the bitmap (X1, X2) is set based on the reference antenna configuration in method 2 of proposal 1.

[0040] Figure 17 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 1 of proposal 2.

[0041] Fig. 18 illustrates another example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 1 of proposal 2.

[0042] Figure 19 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 2 of proposal 2.

[0043] Figure 20 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 3 of proposal 2.

[0044] FIG. 21 is a diagram for explaining the operation of a terminal and a network according to one embodiment.

[0045] FIG. 22 illustrates a flow of a method performed by a terminal according to one embodiment.

[0046] FIG. 23 illustrates a flow of a method performed by a base station according to one embodiment.

[0047] Figures 24 to 27 illustrate communication systems and wireless devices applicable to the present disclosure.

[0048] The following technologies can be used in various wireless access systems, such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with radio technologies such as UTRA (Universal Terrestrial Radio Access) or CDMA2000. TDMA can be implemented with radio technologies such as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA can be implemented with radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (Evolved UTRA). UTRA is a part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (long term evolution) is part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A.

[0049] As more and more communication devices demand greater communication capacity, the need for improved mobile broadband communications compared to existing Radio Access Technology (RAT) is emerging. Furthermore, massive Machine Type Communications (MTC), which connects multiple devices and objects to provide diverse services anytime, anywhere, is also a key issue to be considered in next-generation communications. Furthermore, communication system design that considers reliability and latency-sensitive services / terminals is being discussed. Accordingly, the introduction of next-generation RATs that consider enhanced Mobile BroadBand Communication (eMBB), massive MTC, and Ultra-Reliable and Low Latency Communication (URLLC) is being discussed. For convenience, this technology is referred to as NR (New Radio or New RAT) in the present invention.

[0050] For clarity of explanation, the description will focus on 3GPP NR, but the technical idea of ​​the present invention is not limited thereto.

[0051] In this specification, the expression "setting" can be replaced with the expression "configure / configuration", and the two can be used interchangeably. In addition, conditional expressions (e.g., "if", "in a case", or "when", etc.) can be replaced with the expression "based on that ~~" or "in a state / status". In addition, the operation of the terminal / base station or the SW / HW configuration according to the satisfaction of the condition can be inferred / understood. In addition, if the process of the receiving (or transmitting) side can be inferred / understood from the process of the transmitting (or receiving) side in signal transmission / reception between wireless communication devices (e.g., base stations, terminals), the description thereof can be omitted. For example, signal determination / generation / encoding / transmission, etc. of the transmitting side can be understood as signal monitoring reception / decoding / determination, etc. of the receiving side. In addition, the expression that the terminal performs (or does not perform) a specific operation can also be interpreted as meaning that the base station operates while expecting / assuming (or expecting / assuming that the terminal does not perform) the specific operation. In addition, the expression that the base station performs (or does not perform) a specific operation can also be interpreted as meaning that the terminal operates while expecting / assuming (or expecting / assuming that the base station does not perform) the specific operation. In addition, the division and index of each section, embodiment, example, option, method, plan, etc. in the following description are for the convenience of explanation and should not be interpreted as meaning that each constitutes an independent invention or that each must be implemented only individually. In addition, in describing each section, embodiment, example, option, method, plan, etc., if there is no explicitly conflicting / opposing description, it can be inferred / interpreted that at least some of them can be combined and implemented together, or at least some can be implemented with the omission of each.

[0052] In a wireless communication system, a terminal receives information from a base station via the downlink (DL) and transmits it to the base station via the uplink (UL). The information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type and purpose of the information being transmitted and received.

[0053] Figure 1 is a drawing for explaining physical channels used in a 3GPP NR system and a general signal transmission method using them.

[0054] When a terminal is powered on again from a powered-off state or enters a new cell, it performs an initial cell search operation, such as synchronizing with the base station, in step S101. To this end, the terminal receives a Synchronization Signal Block (SSB) from the base station. The SSB includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). Based on the PSS / SSS, the terminal synchronizes with the base station and obtains information such as a cell ID (cell identity). In addition, the terminal can obtain broadcast information within the cell based on the PBCH. Meanwhile, the terminal can check the downlink channel status by receiving a Downlink Reference Signal (DL RS) during the initial cell search phase.

[0055] After completing the initial cell search, the terminal can obtain more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on the physical downlink control channel information in step S102.

[0056] Thereafter, the terminal may perform a random access procedure such as steps S103 to S106 to complete connection to the base station. To this end, the terminal may transmit a preamble through a physical random access channel (PRACH) (S103) and receive a response message to the preamble through a physical downlink control channel and a corresponding physical downlink shared channel (S104). In the case of contention-based random access, a contention resolution procedure such as transmission of an additional physical random access channel (S105) and reception of a physical downlink control channel and a corresponding physical downlink shared channel (S106) may be performed.

[0057] The terminal that has performed the procedure as described above can then perform the general uplink / downlink signal transmission procedure, such as receiving a physical downlink control channel / physical downlink shared channel (S107) and transmitting a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (S108). The control information that the terminal transmits to the base station is collectively referred to as uplink control information (UCI). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and request Acknowledgement / Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is generally transmitted through PUCCH, but can be transmitted through PUSCH when control information and traffic data must be transmitted simultaneously. Additionally, UCI can be transmitted aperiodically via PUSCH upon request / instruction from the network.

[0058] Figure 2 illustrates the structure of a radio frame. In NR, uplink and downlink transmissions are organized into frames. Each radio frame is 10 ms long and is divided into two 5 ms half-frames (HF). Each half-frame is divided into five 1 ms sub-frames (SF). A sub-frame is divided into one or more slots, and the number of slots within a sub-frame depends on the subcarrier spacing (SCS). Each slot contains 12 or 14 OFDM (Orthogonal Frequency Division Multiplexing) symbols, depending on the cyclic prefix (CP). When a normal CP is used, each slot contains 14 OFDM symbols. When an extended CP is used, each slot contains 12 OFDM symbols.

[0059] Table 1 illustrates that when CP is normally used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS.

[0060] SCS (15*2^u)N slot symb N frame,u slot N subframe,u slot 15KHz (u=0)1410130KHz (u=1)1420260KHz (u=2)14404120KHz (u=3)14808240KHz (u=4)1416016

[0061] * N slot symb : Number of symbols in the slot

[0062] * N frame,u slot : Number of slots in the frame

[0063] * N subframe,u slot : Number of slots in a subframe

[0064] Table 2 illustrates that when extended CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS.

[0065] SCS (15*2^u)N slot symb N frame,u slot N subframe,u slot 60KHz (u=2)12404

[0066] The structure of the frame is only an example, and the number of subframes, number of slots, and number of symbols in the frame can be varied.

[0067] In an NR system, OFDM numerology (e.g., SCS) may be set differently between multiple cells that are merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (conveniently referred to as TU (Time Unit)) consisting of the same number of symbols may be set differently between the merged cells. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol), an SC-FDMA symbol (or Discrete Fourier Transform-spread-OFDM, DFT-s-OFDM symbol).

[0068] Figure 3 illustrates a resource grid of a slot. A slot contains multiple symbols in the time domain. For example, in the case of a regular CP, one slot contains 14 symbols, but in the case of an extended CP, one slot contains 12 symbols. A carrier contains multiple subcarriers in the frequency domain. A Resource Block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) is defined as multiple consecutive Physical RBs (PRBs) in the frequency domain and can correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier can contain up to N (e.g., 5) BWPs. Data communication is performed through activated BWPs, and only one BWP can be activated for a single terminal. Each element in the resource grid is referred to as a Resource Element (RE), to which one complex symbol can be mapped.

[0069] Figure 4 illustrates an example of how physical channels are mapped within a slot. A PDCCH can be transmitted in the DL control region, and a PDSCH can be transmitted in the DL data region. A PUCCH can be transmitted in the UL control region, and a PUSCH can be transmitted in the UL data region. GP provides a time gap between the base station and the terminal when switching from transmission mode to reception mode or from reception mode to transmission mode. Some symbols within a subframe at the time of transition from DL to UL can be set as GP.

[0070] Below, each physical channel is described in more detail.

[0071] The PDCCH carries Downlink Control Information (DCI). For example, the PCCCH (i.e., DCI) carries the transmission format and resource allocation of the downlink shared channel (DL-SCH), resource allocation information for the uplink shared channel (UL-SCH), paging information for the paging channel (PCH), system information on the DL-SCH, resource allocation information for upper layer control messages such as random access responses transmitted on the PDSCH, transmission power control commands, activation / deactivation of Configured Scheduling (CS), etc. The DCI includes a cyclic redundancy check (CRC), which is masked / scrambled with various identifiers (e.g., Radio Network Temporary Identifier, RNTI) depending on the owner or usage of the PDCCH. For example, if the PDCCH is for a specific terminal, the CRC is masked with a terminal identifier (e.g., Cell-RNTI, C-RNTI). If the PDCCH is for paging, the CRC is masked with the Paging-RNTI (P-RNTI). If the PDCCH is for system information (e.g., a System Information Block, SIB), the CRC is masked with the System Information RNTI (SI-RNTI). If the PDCCH is for a random access response, the CRC is masked with the Random Access-RNTI (RA-RNTI).

[0072] The PDCCH consists of 1, 2, 4, 8, or 16 Control Channel Elements (CCEs) depending on the Aggregation Level (AL). A CCE is a logical allocation unit used to provide a PDCCH with a predetermined code rate depending on the radio channel status. A CCE consists of six Resource Element Groups (REGs). A REG is defined as one OFDM symbol and one (P)RB. The PDCCH is transmitted through a Control Resource Set (CORESET). A CORESET is defined as a set of REGs with a given numerology (e.g., SCS, CP length, etc.). Multiple CORESETs for a single UE can overlap in the time / frequency domain. A CORESET can be configured through system information (e.g., Master Information Block, MIB) or UE-specific upper layer (e.g., Radio Resource Control, RRC, layer) signaling. Specifically, the number of RBs and the number of OFDM symbols (up to 3) that constitute the CORESET can be set by upper layer signaling.

[0073] To receive / detect PDCCH, the UE monitors PDCCH candidates. PDCCH candidates represent the CCE(s) that the UE should monitor for PDCCH detection. Each PDCCH candidate is defined as 1, 2, 4, 8, or 16 CCEs depending on the AL. Monitoring involves (blind) decoding the PDCCH candidates. The set of PDCCH candidates that the UE monitors is defined as a PDCCH Search Space (SS). The search space includes a Common Search Space (CSS) or a UE-specific search space (USS). The UE can acquire DCI by monitoring PDCCH candidates in one or more search spaces configured by the MIB or higher-layer signaling. Each CORESET is associated with one or more search spaces, and each search space is associated with one COREST. The search space can be defined based on the following parameters.

[0074] - controlResourceSetId: Indicates the CORESET associated with the search space.

[0075] - monitoringSlotPeriodicityAndOffset: Indicates the PDCCH monitoring period (in slots) and the PDCCH monitoring interval offset (in slots).

[0076] - monitoringSymbolsWithinSlot: Indicates the PDCCH monitoring symbols within the slot (e.g., the first symbol(s) of the CORESET).

[0077] - nrofCandidates: AL={1, 2, 4, 8, 16} indicates the number of PDCCH candidates (one of 0, 1, 2, 3, 4, 5, 6, 8)

[0078] * An opportunity (e.g., time / frequency resource) for monitoring PDCCH candidates is defined as a PDCCH (monitoring) opportunity. One or more PDCCH (monitoring) opportunities can be configured within a slot.

[0079] Table 3 illustrates the characteristics of each search space type.

[0080] TypeSearch SpaceRNTIUse CaseType0-PDCCHCommonSI-RNTI on a primary cellSIB DecodingType0A-PDCCHCommonSI-RNTI on a primary cellSIB DecodingType1-PDCCHCommonRA-RNTI or TC-RNTI on a primary cellMsg2, Msg4 decoding in RACHType2-PDCCHCommonP-RNTI on a primary cellPaging DecodingType3-PDCCHCommonINT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, TPC-SRS-RNTI, C-RNTI, MCS-C-RNTI, or CS-RNTI(s)UE SpecificUE SpecificC-RNTI, or MCS-C-RNTI, or CS-RNTI(s)User specific PDSCH decoding

[0081] Table 4 illustrates DCI formats transmitted via PDCCH.

[0082] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs

[0083] DCI format 0_0 is used to schedule a TB-based (or TB-level) PUSCH, and DCI format 0_1 ​​can be used to schedule a TB-based (or TB-level) PUSCH or a CBG (Code Block Group)-based (or CBG-level) PUSCH. DCI format 1_0 is used to schedule a TB-based (or TB-level) PDSCH, and DCI format 1_1 can be used to schedule a TB-based (or TB-level) PDSCH or a CBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0 / 0_1 may be referred to as UL grant DCI or UL scheduling information, and DCI format 1_0 / 1_1 may be referred to as DL grant DCI or DL ​​scheduling information. DCI format 2_0 is used to convey dynamic slot format information (e.g., dynamic SFI) to the terminal, and DCI format 2_1 is used to convey downlink pre-emption information to the terminal. DCI format 2_0 and / or DCI format 2_1 can be conveyed to the terminals within a group through the group common PDCCH, which is a PDCCH conveyed to the terminals defined as a group.

[0084] DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCI formats, while DCI format 0_1 ​​and DCI format 1_1 may be referred to as non-fallback DCI formats. In the fallback DCI format, the DCI size / field configuration remains the same regardless of the terminal configuration. On the other hand, in the non-fallback DCI format, the DCI size / field configuration varies depending on the terminal configuration.

[0085] PDSCH carries downlink data (e.g., DL-SCH transport block, DL-SCH TB) and applies modulation methods such as Quadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (QAM), 64 QAM, and 256 QAM. TB is encoded to generate a codeword. PDSCH can carry up to two codewords. Scrambling and modulation mapping are performed for each codeword, and modulation symbols generated from each codeword can be mapped to one or more layers. Each layer is mapped to resources along with a Demodulation Reference Signal (DMRS), generated as an OFDM symbol signal, and transmitted through the corresponding antenna port.

[0086] PUCCH carries Uplink Control Information (UCI). UCI includes:

[0087] - SR (Scheduling Request): Information used to request UL-SCH resources.

[0088] - HARQ(Hybrid Automatic Repeat reQuest)-ACK(Acknowledgement): This is a response to a downlink data packet (e.g., codeword) on the PDSCH. It indicates whether the downlink data packet was successfully received. One HARQ-ACK bit can be transmitted in response to a single codeword, and two HARQ-ACK bits can be transmitted in response to two codewords. The HARQ-ACK response includes a positive ACK (simply, ACK), a negative ACK (NACK), a DTX, or a NACK / DTX. Here, HARQ-ACK is used interchangeably with HARQ ACK / NACK and ACK / NACK.

[0089] - CSI (Channel State Information): Feedback information for the downlink channel. MIMO (Multiple Input Multiple Output)-related feedback information includes the Rank Indicator (RI) and Precoding Matrix Indicator (PMI).

[0090] Table 5 illustrates PUCCH formats. Depending on the PUCCH transmission length, they can be classified into Short PUCCH (formats 0 and 2) and Long PUCCH (formats 1, 3, and 4).

[0091] PUCCH formatLength in OFDM symbols N PUCCH symb Number of bitsUsageEtc01 - 2≤2HARQ, SRSequence selection14 - 14≤2HARQ, [SR]Sequence modulation21 - 2>2HARQ, CSI, [SR]CP-OFDM34 - 14>2HARQ, CSI, [SR]DFT-s-OFDM(no UE multiplexing)44 - 14>2HARQ, CSI, [SR]DFT-s-OFDM(Pre DFT OCC)

[0092] PUCCH format 0 carries UCI of up to 2 bits in size and is mapped and transmitted based on sequence. Specifically, the terminal transmits a specific UCI to the base station by transmitting one of multiple sequences through the PUCCH of PUCCH format 0. The terminal transmits the PUCCH of PUCCH format 0 within the PUCCH resources for the corresponding SR configuration only when transmitting a positive SR.

[0093] PUCCH format 1 carries UCI of up to 2 bits in size, and modulation symbols are spread in the time domain using an orthogonal cover code (OCC) (which is set differently depending on whether frequency hopping is used). DMRS are transmitted in symbols where modulation symbols are not transmitted (i.e., transmitted using Time Division Multiplexing (TDM).

[0094] PUCCH format 2 carries UCI with a bit size greater than 2 bits, and modulation symbols are transmitted by frequency division multiplexing (FDM) with DMRS. DM-RSs are located at symbol indices #1, #4, #7, and #10 within a given resource block with a density of 1 / 3. Pseudo Noise (PN) sequences are used for DM_RS sequences. Frequency hopping can be enabled for 2-symbol PUCCH format 2.

[0095] PUCCH format 3 does not multiplex terminals within the same physical resource blocks and carries UCI with a bit size greater than 2 bits. In other words, PUCCH resources in PUCCH format 3 do not include orthogonal cover codes. Modulation symbols are transmitted through time division multiplexing (TDM) with DMRS.

[0096] PUCCH format 4 supports multiplexing of up to four terminals within the same physical resource blocks and carries UCI with a bit size greater than 2 bits. In other words, PUCCH resources in PUCCH format 3 include orthogonal cover codes. Modulation symbols are transmitted through time division multiplexing (TDM) with DMRS.

[0097] At least one of one or more configured cells in a terminal may be configured for PUCCH transmission. At least the primary cell may be configured as a cell for PUCCH transmission. At least one PUCCH cell group may be configured in the terminal based on at least one cell configured for PUCCH transmission, and each PUCCH cell group includes one or more cells. The PUCCH cell group may be simply referred to as a PUCCH group. PUCCH transmission may be configured not only for the primary cell but also for the SCell, and the primary cell belongs to the primary PUCCH group, and the PUCCH-SCell configured for PUCCH transmission belongs to the secondary PUCCH group. For cells belonging to the primary PUCCH group, the PUCCH on the primary cell may be used, and for cells belonging to the secondary PUCCH group, the PUCCH on the PUCCH-SCell may be used.

[0098] PUSCH carries uplink data (e.g., UL-SCH transport block, UL-SCH TB) and / or uplink control information (UCI), and is transmitted based on a CP-OFDM (Cyclic Prefix - Orthogonal Frequency Division Multiplexing) waveform or a DFT-s-OFDM (Discrete Fourier Transform - spread - Orthogonal Frequency Division Multiplexing) waveform. When the PUSCH is transmitted based on a DFT-s-OFDM waveform, the UE transmits the PUSCH by applying transform precoding. For example, when transform precoding is disabled (e.g., transform precoding is disabled), the UE transmits the PUSCH based on the CP-OFDM waveform, and when transform precoding is enabled (e.g., transform precoding is enabled), the UE can transmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmissions can be dynamically scheduled by UL grants in DCI, or semi-statically scheduled (configured grant) based on higher layer (e.g., RRC) signaling (and / or Layer 1 (L1) signaling (e.g., PDCCH)). PUSCH transmissions can be performed in a codebook-based or non-codebook-based manner.

[0099] Figure 5 illustrates an ACK / NACK transmission process. Referring to Figure 5, a terminal can detect a PDCCH in slot #n. Here, the PDCCH includes downlink scheduling information (e.g., DCI formats 1_0, 1_1), and the PDCCH indicates a DL assignment-to-PDSCH offset (K0) and a PDSCH-HARQ-ACK reporting offset (K1). For example, DCI formats 1_0, 1_1 can include the following information:

[0100] - Frequency domain resource assignment: Indicates the set of RBs allocated to the PDSCH.

[0101] - Time domain resource assignment: K0 (e.g., slot offset), indicates the starting position of the PDSCH within slot #n+K0 (e.g., OFDM symbol index), and the length of the PDSCH (e.g., number of OFDM symbols).

[0102] - PDSCH-to-HARQ_feedback timing indicator: Indicates K1

[0103] - HARQ process number (4 bits): Indicates the HARQ process ID (Identity) for data (e.g., PDSCH, TB)

[0104] - PUCCH resource indicator (PRI): Indicates the PUCCH resource to be used for UCI transmission among multiple PUCCH resources within the PUCCH resource set.

[0105] Afterwards, the terminal receives PDSCH from slot #(n+K0) according to the scheduling information of slot #n, and when reception of PDSCH is finished in slot #n1 (where, n+K0≤n1), UCI can be transmitted through PUCCH in slot #(n1+K1). Here, UCI may include HARQ-ACK response for PDSCH. In Fig. 5, for convenience, it is assumed that SCS for PDSCH and SCS for PUCCH are the same and slot # n1 = slot #n+K0, but the present invention is not limited thereto. If the SCSs are different, K1 can be indicated / interpreted based on the SCS of PUCCH.

[0106] When the PDSCH is configured to transmit at most 1 TB, the HARQ-ACK response may consist of 1 bit. When the PDSCH is configured to transmit at most 2 TB, the HARQ-ACK response may consist of 2 bits if spatial bundling is not configured, and may consist of 1 bit if spatial bundling is configured. When the HARQ-ACK transmission timing for multiple PDSCHs is designated as slot #(n+K1), the UCI transmitted in slot #(n+K1) includes HARQ-ACK responses for multiple PDSCHs.

[0107] Whether a UE should perform spatial bundling for a HARQ-ACK response can be configured (e.g., via RRC / higher layer signaling) for each cell group. For example, spatial bundling can be individually configured for each HARQ-ACK response transmitted over the PUCCH and / or each HARQ-ACK response transmitted over the PUSCH.

[0108] Spatial bundling can be supported when the maximum number of TBs (or codewords) that can be received at a time (or scheduled via 1 DCI) in the serving cell is 2 (or more than 2) (e.g., when the upper layer parameter maxNrofCodeWordsScheduledByDCI corresponds to 2-TB). Meanwhile, more than 4 layers can be used for 2-TB transmission, and up to 4 layers can be used for 1-TB transmission. Consequently, when spatial bundling is configured for the cell group, spatial bundling can be performed for serving cells that can schedule more than 4 layers among the serving cells in the cell group. On the serving cell, a terminal that wishes to transmit a HARQ-ACK response via spatial bundling can generate the HARQ-ACK response by performing a (bit-wise) logical AND operation on the A / N bits for multiple TBs.

[0109] For example, assuming that a terminal receives a DCI scheduling 2 TB and receives 2 TB via PDSCH based on the DCI, the terminal performing spatial bundling can generate a single A / N bit by logically ANDing the first A / N bit for the first TB and the second A / N bit for the second TB. Consequently, if both the first TB and the second TB are ACK, the terminal reports the ACK bit value to the base station, and if either TB is NACK, the terminal reports the NACK bit value to the base station.

[0110] For example, if only 1-TB is actually scheduled on a serving cell configured to receive 2-TB, the terminal can generate a single A / N bit by logically ANDing the A / N bit for the 1-TB with bit value 1. Consequently, the terminal reports the A / N bit for the 1-TB to the base station as is.

[0111] A base station / terminal has multiple parallel DL HARQ processes for DL ​​transmission. These multiple parallel HARQ processes allow DL transmissions to be performed continuously while waiting for HARQ feedback regarding the success or failure of the previous DL transmission. Each HARQ process is associated with a HARQ buffer in the MAC (Medium Access Control) layer. Each DL HARQ process manages state variables such as the number of transmissions of MAC Physical Data Blocks (PDUs) in the buffer, HARQ feedback for MAC PDUs in the buffer, and the current redundancy version. Each HARQ process is identified by a HARQ process ID.

[0112] Figure 6 illustrates a PUSCH transmission process. Referring to Figure 6, a terminal can detect a PDCCH in slot #n. Here, the PDCCH includes uplink scheduling information (e.g., DCI formats 0_0 and 0_1). DCI formats 0_0 and 0_1 can include the following information.

[0113] - Frequency domain resource assignment: Indicates the set of RBs allocated to PUSCH.

[0114] - Time domain resource assignment: Slot offset K2 indicates the starting position (e.g., symbol index) and length (e.g., number of OFDM symbols) of the PUSCH within the slot. The starting symbol and length can be indicated through SLIV (Start and Length Indicator Value) or can be indicated separately.

[0115] Thereafter, the terminal can transmit a PUSCH in slot #(n+K2) according to the scheduling information of slot #n. Here, the PUSCH includes a UL-SCH TB.

[0116] CSI-related actions

[0117] Figure 7 shows an example of a CSI-related procedure.

[0118] The terminal receives configuration information related to CSI from the base station via RRC signaling (710). The configuration information related to CSI may include at least one of CSI-IM (interference management) resource-related information, CSI measurement configuration-related information, CSI resource configuration-related information, CSI-RS resource-related information, or CSI report configuration-related information.

[0119] - CSI-IM resources can be configured for interference measurement (IM) of the terminal. In the time domain, the CSI-IM resource set can be configured periodically, semi-persistently, or aperiodicly. The CSI-IM resources can be configured as Zero Power (ZP)-CSI-RS for the terminal. The ZP-CSI-RS can be configured separately from the Non-Zero Power (NZP)-CSI-RS.

[0120] - The UE may assume that the CSI-RS resource(s) for channel measurement configured for one CSI reporting and the CSI-IM / NZP CSI-RS resource(s) for interference measurement (when NZP CSI-RS resource(s) are used for interference measurement) are in a QCL relationship with respect to 'QCL-TypeD' per resource.

[0121] - The CSI resource configuration may include at least one of a CSI-IM resource for interference measurement, an NZP CSI-RS resource for interference measurement, and an NZP CSI-RS resource for channel measurement. The CMR (channel measurement resource) may be an NZP CSI-RS for CSI acquisition, and the IMR (Interference measurement resource) may be an NZP CSI-RS for CSI-IM and IM.

[0122] - CSI-RS can be configured for one or more terminals. Different CSI-RS configurations may be provided for each terminal, or the same CSI-RS configuration may be provided to multiple terminals. CSI-RS can support up to 32 antenna ports. CSI-RS corresponding to N (N is 1 or greater) antenna ports can be mapped to N RE locations within a time-frequency unit corresponding to one slot and one RB. When N is 2 or greater, N-port CSI-RS can be multiplexed using CDM, FDM, and / or TDM schemes. CSI-RS can be mapped to REs other than REs to which CORESET, DMRS, and SSB are mapped. In the frequency domain, CSI-RS can be configured for the entire bandwidth, a portion of the bandwidth (BWP), or a portion of the bandwidth. CSI-RS may be transmitted in each RB within the bandwidth for which CSI-RS is configured (i.e., density = 1), or in every second RB (e.g., even or odd RB) (i.e., density = 1 / 2). When CSI-RS is used as a Tracking Reference Signal (TRS), a single-port CSI-RS may be mapped on three subcarriers in each resource block (i.e., density = 3). One or more CSI-RS resource sets may be configured for a UE in the time domain. Each CSI-RS resource set may include one or more CSI-RS configurations. Each CSI-RS resource set may be configured periodically, semi-persistently, or aperiodicly.

[0123] - The CSI report configuration may include configurations for feedback type, measurement resources, report type, etc. The NZP-CSI-RS resource set may be used for the CSI report configuration of the corresponding terminal. The NZP-CSI-RS resource set may be associated with CSI-RS or SSB. In addition, multiple periodic NZP-CSI-RS resource sets may be configured as TRS resource sets. (i) The feedback type may include a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a CSI-RS Resource Indicator (CRI), an SSB Resource block Indicator (SSBRI), a Layer Indicator (LI), a Rank Indicator (RI), a Layer 1-Reference Signal Received Strength (RSRP), etc. (ii) Measurement resources may include configurations for downlink signals and / or downlink resources on which the terminal performs measurements to determine feedback information. The measurement resources may be configured as ZP and / or NZP CSI-RS resource sets associated with CSI reporting configurations. The NZP CSI-RS resource set may include a CSI-RS set or an SSB set. For example, L1-RSRP may be measured for a CSI-RS set or an SSB set. (iii) Reporting types may include configurations for a time point at which the terminal performs reporting and an uplink channel, etc. The reporting time point may be configured as periodic, semi-persistent, or aperiodic. Periodic CSI reporting may be transmitted on PUCCH. Semi-persistent CSI reporting may be transmitted on PUCCH or PUSCH based on a MAC CE indicating activation / deactivation. Aperiodic CSI reporting may be indicated by DCI signaling.For example, the CSI request field of an uplink grant may indicate one of several report trigger sizes. Aperiodic CSI reports may be transmitted on the PUSCH.

[0124] The terminal measures CSI based on configuration information related to CSI. CSI measurement may include a procedure of receiving a CSI-RS (720) and computing the received CSI-RS to acquire CSI (730).

[0125] The UE can transmit a CSI report to the base station (740). For the CSI report, the time and frequency resources that the UE can use are controlled by the base station. The CSI (channel state information) can include at least one of a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), an SS / PBCH block resource indicator (SSBRI), a layer indicator (LI), a rank indicator (RI), L1-RSRP, and / or L-SINR.

[0126] The time domain behavior of CSI reporting supports periodic, semi-persistent, and aperiodic. i) Periodic CSI reporting is performed on short PUCCH and long PUCCH. The periodicity and slot offset of periodic CSI reporting can be configured by RRC, and refer to the CSI-ReportConfig IE. ii) SP (semi-periodic) CSI reporting is performed on short PUCCH, long PUCCH, or PUSCH. In case of SP CSI on short / long PUCCH, the periodicity and slot offset are configured by RRC, and CSI reporting is activated / deactivated by separate MAC CE / DCI. In case of SP CSI on PUSCH, the periodicity of SP CSI reporting is configured by RRC, but the slot offset is not configured by RRC, and SP CSI reporting is activated / deactivated by DCI (format 0_1). For SP CSI reporting on PUSCH, a separate RNTI (SP-CSI C-RNTI) is used. The initial CSI reporting timing follows the PUSCH time domain allocation value indicated in the DCI, and subsequent CSI reporting timings follow the cycle set by RRC. DCI format 0_1 ​​includes a CSI request field and can activate / deactivate a specific configured SP-CSI trigger state. SP CSI reporting has the same or similar activation / deactivation mechanism as the data transmission mechanism on the SPS PUSCH.iii) Aperiodic CSI reporting is performed on PUSCH and is triggered by DCI. In this case, information related to the triggering of aperiodic CSI reporting can be transmitted / indicated / configured via MAC-CE. For AP CSI with AP CSI-RS, the AP CSI-RS timing is configured by RRC, and the timing for AP CSI reporting is dynamically controlled by DCI.

[0127] CSI codebooks defined in the NR standard (e.g., PMI codebooks) can be broadly divided into Type I and Type II codebooks. Type I codebooks are primarily targeted at SU (Single User)-MIMO, which supports both high-order and low-order signals. Type II codebooks can primarily support MI-MIMO, which supports up to two layers. Compared to Type I, Type II codebooks can provide more accurate CSI, but may increase signaling overhead. Meanwhile, Enhanced Type II codebooks were introduced to address the CSI overhead shortcomings of existing Type II codebooks. Enhanced Type II codebooks were introduced by reducing the codebook payload by considering frequency-axis correlation.

[0128] CSI reporting via PUSCH can be configured as Part 1 and Part 2. Part 1 has a fixed payload size and is used to identify the number of information bits in Part 2. Part 1 is transmitted in its entirety before Part 2.

[0129] - For Type I CSI feedback, Part 1 contains the RI (if reported), the CRI (if reported), and the CQI of the first code word. Part 2 contains the PMI, and when RI > 4, Part 2 contains the CQI.

[0130] - For Type II CSI feedback, Part 1 contains the RI (if reported), CQI, and an indication of the number of non-zero WB amplitude coefficients per layer of Type II CSI. Part 2 contains the PMI of Type II CSI.

[0131] - For Enhanced Type II CSI feedback, Part 1 contains the RI (if reported), CQI, and the total number of non-zero WB amplitude coefficients for all layers of Enhanced Type II CSI. Part 2 contains the PMI of Enhanced Type II CSI.

[0132] If CSI reporting on PUSCH includes two parts and the CSI payload to be reported is less than the payload size provided by the PUSCH resources allocated for CSI reporting, the UE may omit part of Part 2 CSI.

[0133] Meanwhile, semi-persistent CSI reporting performed in PUCCH format 3 or 4 supports Type II CSI feedback, but only Part 1 of Type II CSI feedback.

[0134] QCL (quasi-co location)

[0135] Two antenna ports are quasi-co-located if the channel properties of one antenna port can be inferred from the channel properties of the other antenna port. The channel properties may include one or more of Delay spread, Doppler spread, Frequency / Doppler shift, Average received power, Received Timing / average delay, and Spatial RX parameters.

[0136] A terminal can configure a list of multiple TCI-State configurations via the upper layer parameter PDSCH-Config. Each TCI-State is associated with one or two DL reference signals and a QCL configuration parameter between the DM-RS port of the PDSCH. The QCL can include qcl-Type1 for the first DL RS and qcl-Type2 for the second DL RS. The QCL type can correspond to one of the following:

[0137] - 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}

[0138] - 'QCL-TypeB': {Doppler shift, Doppler spread}

[0139] - 'QCL-TypeC': {Doppler shift, average delay}

[0140] - 'QCL-TypeD': {Spatial Rx parameter}

[0141] Figure 8 illustrates the antenna configuration and the port configuration within the panel.

[0142] Referring to FIG. 8, the antenna configuration (910) can be set for the first domain (1st domain) and the second domain (2nd domain), and TXRU virtualization can be applied in relation to the antenna configuration (910) in relation to the port configuration (920).

[0143] With respect to the antenna configuration (910), M represents the number of columns in the panel (i.e., the number of antenna ports in the first domain within the panel), N represents the number of rows in the panel (i.e., the number of antenna ports in the second domain within the panel), P represents polarization (1: co-pol, 2: X-pol), Mg represents the number of panels in the first domain, and Ng represents the number of panels in the second domain. Accordingly, the total number of antenna elements can be expressed as P*M*N*Mg*Ng. As an example, the antenna configuration (910) illustrated in FIG. 8 corresponds to [(M, N, P, Mg, Ng) = (4, 4, 2, 2, 2)]. In Fig. 8, dgH represents panel spacing in the first domain, dgV represents channel spacing in the second domain, dH represents antenna spacing in the first domain, and dV represents antenna spacing in the second domain.

[0144] With respect to the panel configuration (920), N1 represents the number of columns in the first domain (the number of antenna ports in the first domain within the panel), N2 represents the number of rows in the second domain (the number of antenna ports in the second domain within the panel), and P represents polarization (1: co-pol, 2: X-pol). Accordingly, the total number of CSI-RS ports in the panel can be expressed as P*N1*N2. For example, the panel configuration (920) illustrated in FIG. 8 corresponds to [(N1, N2, P) = (2, 2, 2)].

[0145] CSI Codebook

[0146] CSI codebooks defined in the NR standard (e.g., PMI codebooks) can be broadly categorized into Type I and Type II codebooks. For a deeper understanding of these codebooks, refer to Section 5.2.2.2 of TS 38.214 (incorporated by reference).

[0147] (1) Type I codebook

[0148] Type I codebooks primarily target Single User (SU)-MIMO, which supports both high-order and low-order signals. Type I codebooks can be divided into (i) single-panel codebooks and (ii) multi-panel codebooks. (i) A single-panel codebook may be based on the assumption that a terminal receives downlink transmissions from a single antenna panel. (ii) A multi-panel codebook may support base station configurations that use multiple (e.g., two or four) antenna panels. Unlike a single-panel codebook, which supports ranks 1 through 8, a multi-panel codebook can support ranks 1 through 4.

[0149] A Type I codebook can be configured with the selection of preferred DFT vector(s) from an oversampled DFT vector set as a spatial domain basis and the indication of co-phase for cross polarization of the base station antenna.

[0150] As an example, the codeword vector for 1-layer transmission for a 1D array antenna can be defined based on mathematical expression 1.

[0151]

[0152] In mathematical expression 1, N represents the number of antenna elements included in the 1D antenna array, O represents an oversampling factor, and the index of the codebook vector l can be 0, 1, 2..., O*N-1.

[0153] Meanwhile, the precoder vector for a 2D antenna array can be defined based on the Kronecker product between two 1D array precoder vectors.

[0154] (2) Type II codebook

[0155] Type II codebooks can primarily support MI-MIMO, which supports up to two layers. Compared to Type I, Type II codebooks can provide more accurate CSI, but may increase signaling overhead. In a Type II codebook, the PMI can identify a set of beams and a set of amplitude coefficients. The amplitude coefficients can be used to generate a weighted sum of the beams. Type II codebooks can also identify the phase shift due to co-phasing between beams. Type II port selection codebooks can support wideband / long-term CSI (e.g., i1) and subband / short-term CSI (e.g., i2) reporting based on precoded (or beamformed) CSI-RSs when the base station knows information about the channel between the terminal and the base station.

[0156] For Type II codebooks, multiple DFT vectors are selected as SD basis, and the selected DFT vectors are linearly combined to achieve high resolution and excellent MU-MIMO performance.

[0157] Meanwhile, the enhanced Type II codebook was introduced to address the CSI overhead shortcomings of the existing Type II codebook by reducing the payload of the codebook by considering the correlation of the frequency axis.

[0158] Figure 9 is a diagram illustrating the structure of an enhanced Type II codebook.

[0159] Referring to Fig. 9, the precoding matrix W in the enhanced Type II codebook can be expressed as W = W1*W2*W3. W1 corresponds to the SD basis related to SD compression, W3 corresponds to the FD basis related to FD compression, and W2 corresponds to linear combining (LC) coefficients according to the FD compression of W3. When the terminal determines the matrix W as the PMI of the enhanced Type II, it reports the indices of W1, the coefficients of W2, and the indices of W3 to the network. The dimension of the matrix W is P(=2N1*N2)*N3, where W1 is P*2L, W2 is 2L*M, and W3 is N3*M. The terminal selects 2L basis beam vectors with respect to W1, M LC coefficients with respect to W2, and M FD basis vectors with respect to W3 (wherein each vector is an orthogonal DFT vector with a size of N3*1). L is the number of SD beams as a parameter for SD compression, which can be 2, 3, or 6. N3 and M are parameters for FD compression, where N3 is the DFT size for FD compression, and N3=N SB *It is expressed as R, where R is the granularity between CQI and PMI and can be 1 or 2.

[0160] The enhanced Type II codebook vector constituting the l-th layer is expressed as in mathematical expression 2.

[0161]

[0162]

[0163] In Equation 2, l = 1, 2, 3, 4, and N1 and N2 represent the lengths of the first and second spatial domains (SD) of each base station (or each port group). vm1 (i) , m2 (j) (i=0,1,...,L-1) are L SD DFT vectors selected for linear combining (e.g., they can be 1-dimensional DFT vectors or 2-dimensional DFT vectors depending on the antenna geometry of each base station). The codebook vectors are determined by the parameters q1, q2, n1, and n2, which correspond to parameters introduced to select the optimal L beams among a total of Q1*N1*Q2*N2 beams (where Q1 and Q2 are oversampling factors for the first and second domains). n3 is a parameter introduced to select a frequency domain (FD) DFT basis. p l (1) , p l (2) corresponds to the amplitude coefficient. p l (1) is an indicator of a 4-bit quantization level, and is an indicator that indicates the relative amplitude through 4 bits based on the largest value among the strongest coefficients (p_ref) for each polarization for each layer (polarization with the strongest coefficient). p l (2) corresponds to an indicator indicating the relative amplitude of 3 bits based on p_ref within each polarity. The 4-bit phase coefficient indicator is i ,2,5,l and this is φ l,i,f is associated with . t represents the frequency domain index (t=0,...,N3-1, e.g., a group of PRBs or subbands), and y is a DFT vector of length-N3, which is the FD basis. t,l (f) Each element can correspond to Mv. Mv corresponds to the number of FD bases selected by the terminal among N3 FD bases.

[0164] CBSR (codebook subset restriction) for upto 128 port CSI-RS

[0165] First, a brief summary of CBSR in the existing NR standard supporting up to 32 ports of CSI-RS is as shown in Table 6.

[0166]

[0167]

[0168] In the following description, a channel measurement resource (CMR) may include a CSI-RS resource configured for channel measurement (e.g., non-zero power CSI-RS). An interference measurement resource (IMR) may include a CSI-RS resource configured for interference measurement (e.g., zero / non-zero power CSI-RS).

[0169] In Rel-19 NR MIMO or later standards, CSI supporting up to 128 CSI-RS ports in FR1 can be considered to increase system throughput of DL / UL and for more flexible MIMO operation.

[0170] a. Type-I codebook refinement supporting up to a total of 128 CSI-RS ports across all resources, assuming legacy CSI-RS resources (with up to 32 CSI-RS ports per resource), based on extension of legacy codebooks.

[0171] b. Type-II codebook refinement supporting up to a total of 128 CSI-RS ports across all resources, assuming legacy CSI-RS resources (with up to 32 CSI-RS ports per resource), based on extension of legacy codebooks, without modifying any codebook parameter other than introducing additional values ​​for the number of ports codebook parameter(s).

[0172] c. Extension of CRI(s)-based CSI reporting (CQI / PMI / RI calculated per CRI for ≥1 CRI) for hybrid beamforming supporting up to a total of 128 CSI-RS ports across all resources, with up to 32 CSI-RS ports per resource, without new codebook design.

[0173] Table 7 shows the consensus reached at the recent NR standardization meeting for refinement up to 128 CSI-RS ports for the Rel-19 Type-I codebook, for cases where RI = 1-4.

[0174] (1) Scheme1 (baseline): Add new (N1, N2) values ​​to the Rel-15 Type-I single panel codebook so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource. (2) Scheme2: Add new (N1, N2) values ​​so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource. - W1 structure: For each layer, reuse the Rel-16 eType-II SD basis to determine the DFT-based SD basis candidate with L=1. For 4≥RI>1, L=1 SD basis vectors are independently selected for different layers. - W2 structure: inter-polarization M-PSK co-phasing, M is selected from {2, 4, 8, 16}. (3) Scheme2B: Add new (N1, N2) values ​​so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource. - W1 structure: For each layer, determine L=1 DFT-based SD basis candidates. For 4≥RI>1, L=1 SD basis vectors are independently selected for different layers.- W2 Structure: 1) Option 1: Layer-specific inter-polarization amplitude and phase scaling (single scaling coefficient per polarization) 2) Option 2: Layer-specific intra-polarization (two scaling coefficients per polarization) amplitude and phase scaling (4) Scheme 3: Add new (N1, N2) values ​​so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource, - W1 Structure: Reuse Rel-16 eType-II SD basis to determine DFT-based SD basis candidate with L>1, and the notation of SD basis index follows Rel-16 eType-II. For 4≥RI>1, L>1 SD basis vectors are commonly selected across layers. - W2 structure:1) Option 1: Layer-specific sub-band SD basis selection (one of L) and inter-polarization M-PSK co-phasing, M is selected from {2, 4, 8, 16}2) Option 2: 2: Layer-specific wideband SD basis linear combination and inter-polarization scaling coefficient (e.g., amplitude scaling + M-PSK co-phasing), M is selected from {2, 4, 8, 16} (5) Scheme4: Using a Rel-15 Type-I codebook containing the existing (N1, N2) values ​​for each NZP CSI-RS resource (or port group), the PMI (associated with W1 and W2) is computed as follows.- W1 structure: Reuse Rel-15 Type-I SD basis with L=1 or L=4, calculated per NZP CSI-RS resource (or port group) - W2 structure: Reuse existing Rel-15 Type-I inter-polarization co-phasing per NZP CSI-RS resource (or port group) with inter-NZP CSI-RS resource (or port group) co-phasing. inter-CSI-RS resource (or port group) co-phasing is used to combine different PMIs to obtain a single precoder with >32 ports. (6) Scheme 5: Add a new (N1, N2) value so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource, and expand the set of orthogonal beams for the second beam selection based on the Rel-15 Type-I single panel codebook. (i1,1, i1,2) is used to represent the first beam as in the existing values ​​of Rel-15 Type-I. The second beam is selected from the expanded set of orthogonal beams with size (N1 -1)N2O2 + (N2 -1)N1O1 - (N1 -1)(N2 -1). (7) Scheme 6: Add a new (N1, N2) value so that 2N1N2 (>32) is the total number of CSI-RS ports of the aggregated NZP CSI-RS resource. The number of ports is set to be the same, and beams are selected per antenna group or NZP CSI-RS resource. The various beams are combined using inter-group (or CSI-RS resource) co-phasing along with inter-polarization co-phasing per group (or CSI-RS resource).

[0175] When a codebook supporting up to 128-port CSI-RS is created, we propose a method to reduce the overhead of codebook subset restriction (CBSR).

[0176] For example, in the case of the existing NR Type I CSI as described in Table 6, restriction on / off instructions for each basis are performed through RRC signaling of a bitmap having bits corresponding to the size of the spatial domain basis (SD basis) (e.g., N1O1N2O2 for 2D antenna, N1*O1 for 1D antenna). The terminal reports CSI to the base station without including the SD basis indicated by the RRC when calculating / reporting CSI. This CBSR is a measure to reduce the interference that the base station has on other cells.

[0177] In general, the number of SD basis of NR Type 1 CSI is set based on the base station antenna configuration and codebook oversampling factor, so the required number of CBSR bits is N1*N2*O1*O2 bits for a 2D antenna layout, and N1*O1 bits for a 1D antenna layout. Here, N1 and N2 are the number of antennas in the 1st domain and the number of antennas in the 2nd domain of the base station antenna configuration, respectively, and O1 and O2 are the oversampling factor of the 1st domain and the oversampling factor of the 2nd domain, respectively. Therefore, in the case of the existing 32-port CSI-RS of NR, the maximum is N1*N2*O1*O2, which becomes 16*4*4 = 256 bits.

[0178] If the existing bitmap signaling for CBSR were extended to 128 ports in the same manner, the bitmap size would become 64*4*4 = 1024 bits, significantly increasing RRC overhead. This specification proposes a method to effectively reduce this overhead and perform CBSR.

[0179] Proposal 1

[0180] When reporting CSI in NR (e.g., Type I CSI or Type II CSI), the max CBSR bit number (X) for CBSR (e.g., X=256 bits) and the X-bitmap for CBSR are indicated / set to the terminal, and the CBSR X-bitmap can be reinterpreted based on the following methods.

[0181] - Method 1: In addition to the above X-bitmap, a starting SD basis index can be indicated, and the terminal understands and operates that CBSR (ie, "on" / "off") for X SD basis is set based on the above starting SD basis index.

[0182] - Method 2: A bit in the bitmap can be pre-defined to indicate restriction of multiple SD basis indices, or separate explicit signaling can be added for this.

[0183] Fig. 10 illustrates a bitmap for CBSR according to Method 1 of Proposal 1. In Fig. 10, 32*16 indices represent SD basis indices of 64-port CSI-RS (N1=8, N2=4, O1=4, O2=4, X=256). As a starting SD basis index, it is assumed that 4 is indicated as the N1 domain and 2 is indicated as the N2 domain, and for the convenience of explanation, this is denoted as (N1, N2) = (4,2). The terminal understands that a 256-bitmap (indicated by shading) is indicated starting from the starting index (indicated in black) (N1 first mapping of the bitmap), and does not include the SD index indicated as “0” in the bitmap when reporting / calculating CSI. When reporting / calculating CSI, (N1, N2) = (8,9), (9,9), (10,9), … , the terminal can understand that the 10 SD indices of (17,9) are not used. In Fig. 10, the bitmap represents N1 first mapping, but N2 first mapping may be used depending on the embodiment.

[0184] The value of bitmap length X in Proposal 1 can be determined in advance as a specific value or can be separately set by the base station (e.g., RRC, MAC-CE, DCI). In addition, the value for the starting point in Method 1 of Proposal 1 can also be indicated by the base station as a dynamic setting (e.g., MAC-CE, DCI) other than a separate RRC setting. This is to effectively set interference control that takes into account changes in location and direction between the terminal and the base station, taking into account the mobility of the terminal.

[0185] As another embodiment of the above proposal 1 method 1, the starting position can be indicated only for one direction of the N1 domain or the N2 domain. And, for directions other than the direction indicated by the starting position, it can be promised that X bit-maps start from a specific index (e.g., 0).

[0186] Fig. 11 illustrates another example of a bitmap for CBSR according to method 1 of proposal 1. In Fig. 11, it is assumed that the starting point is indicated by index 12 of the N2 domain for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4, X=256).

[0187] In this case, the 256-bitmap starts at (N1, N2) = (12,0), and the restricted SD basis is the 10 SD indices of (N1, N2) = (8,2), (9,2), (10,2), ..., (17,2). The terminal can understand that the above SD index is not included when reporting / calculating CSI.

[0188] Meanwhile, in the above proposal 1 method 1, if the length of the bitmap exceeds the value of N1*N2*O1*O2, it can be wrapped around and start from (0,0). For example, it can be promised that the modulo N1*N2*O1*O2 operation is applied.

[0189] In the case of method 2 of proposal 1, one CBSR bit in the CBSR bitmap restricts multiple SD basis.

[0190] Figures 12 and 13 illustrate bitmaps for CBSR based on method 2 of proposal 1.

[0191] First, referring to FIG. 12, FIG. 12 (a) shows a 256-bitmap signaled for CBSR, and FIG. 12 (b) shows SD beam indices that are restricted based on the bitmap.

[0192] Here, the bitmap is represented as a 2D bitmap for convenience of explanation, but a 1D bitmap may also be set / indicated, in which case the 1D bitmap may be expressed and indicated in the N1 first mapping (or N2 first mapping) manner in the above 2D bitmap. For example, the bits corresponding to N2 index 0 of the bitmap may be mapped in the order of MSB first, followed by bits corresponding to N2 index 1.

[0193] As represented by the same shading pattern between (a) and (b) in Fig. 12, one bit of the bitmap indicates whether or not to restrict two SD indices of the N1 domain. For example, the second bit of the bitmap (the bit marked black, 0) indicates that the SD indices of (N1, N2) = (2,0), (3,0) are restricted.

[0194] Referring to FIG. 13, FIG. 13 (a) represents a 128-bitmap, and FIG. 13 (b) represents a restricted SD beam index based on the 128-bitmap. One bit of the bitmap restricts two SD indices each of the N1 domain and the N2 domain (a total of four SD beam indices per bit). For example, the second bit of the bitmap (black, bit marked as 0) restricts four SD indices of (N1, N2) = (2,0), (3,0), (2,1), (3,1).

[0195] In method 2 of the above proposal 1, a pre-defined rule can be set to restrict a bit of one bitmap to multiple SD indices, and in one of the methods, it can be implicitly determined by the relationship between N1, O1, N2, and O2.

[0196] For example, the number of SD beam indices corresponding to restriction can be determined by the length of each domain of the 2D bitmap and the actual setting values ​​of N1, O1, N2, and O2.

[0197] For example, if the length of the N1 domain (e.g., the first domain or the first direction) in the X-bitmap for CBSR is X1 and the length of the N2 domain (e.g., the second domain or the second direction) is X2, the X-bitmap may include X1X2 bits (X=X1*X2). The number of restriction SD basis per bit in the X-bitmap (e.g., the number of precoder components (vectors)) M may be determined based on the ratio values ​​(N1*O1) / X1 and (N2*O2) / X2. N1 may represent the number of antennas in the first domain, O1 may represent the first oversampling factor, N1 may represent the number of antennas in the first domain, O1 may represent the first oversampling factor, N2 may represent the number of antennas in the second domain, and O2 may represent the second oversampling factor. For example, when (N1*O1) / X1 = S1 and (N2*O2) / X2 = S2, S1 may represent the number of SD basis (e.g., precoder components (vectors)) per bit in the N1 domain (e.g., the first domain or the first direction), and S2 may represent the number of SD basis (e.g., precoder components (vectors)) per bit in the N2 domain (e.g., the second domain or the second direction). Accordingly, S1*S2 SD basis may be linked per each bit. In other words, multiple groups (e.g., SD basis vector groups) may be set based on X1 and X2, and each group may include S1*S2 (=(N1*O1) / X1 * (N2*O2) / X2) SD basis vectors, and each group may correspond to each bit of the bitmap. Depending on the value 0 / 1 of each bit, whether CBSR is applied to S1*S2 SD basis (e.g., S1*S2 SD basis of the group) associated with the bit can be indicated. Since whether CBSR is applied is indicated in group units in this way, it can be applied to antenna ports exceeding 32 (e.g., 48, 64, 128) can solve the problem of increasing signaling overhead of bitmap for CBSR when CSI-RS is used.

[0198] The base station can determine a subset of precoders that can be used for CSI reporting of the terminal (e.g., precoders to which CBSR is not applied) and a subset of precoders that cannot be used for CSI reporting (e.g., precoders to which CBSR is applied) from a codebook (e.g., Type 1 PMI codebook or Type II PMI codebook), and determine the X1 and X2 values ​​based on the subset.

[0199] The base station may explicitly signal (e.g., upper layer signaling) the values ​​of X1 and X2 of the terminal to determine them. For example, the values ​​of X1 and X2 may be RRC signaled together with or separately from the bitmap.

[0200] And / or, for 32 ports or more, a reference antenna configuration can be set / indicated.

[0201] - For example, in the case of 128 port CSI-RS, it can be set based on 32 port CSI-RS, and 1 bit can be predefined / set to restrict 4 SD basis.

[0202] - For example, in the case of 64 port CSI-RS, it can be set based on 32 port CSI-RS, and 1 bit can be predefined / set to restrict 2 SD basis.

[0203] - For example, in the case of 48 port CSI-RS, it can be set based on 24 port CSI-RS, and 1 bit can be predefined / set to restrict 2 SD basis.

[0204] - For example, for CSI-RS exceeding 32 ports, (X1, X2) combinations that the base station can set for the terminal can be predefined (e.g., configured as a table), and the base station can indicate one (X1, X2) combination among the combinations to the terminal. Specifically, (X1, X2) combinations can be predefined for each number of antenna ports and each (N1, N2) combination. For example, a Table may be configured such that a plurality of (X1, X2) combinations are predefined for a first number of antenna ports and a first (N1, N2) combination, another plurality of (X1, X2) combinations are predefined for a first number of antenna ports and a second (N1, N2) combination, and another plurality of (X1, X2) combinations are predefined for a second number of antenna ports and a third (N1, N2) combination, and the base station may indicate to the terminal, through RRC signaling, any one (X1, X2) combination among the plurality of (X1, X2) combinations predefined for the number of antenna ports and the (N1, N2) combination set in the terminal.

[0205] For example, when X1 and X2 are set based on the reference antenna configuration, since the beam width constituting the reference antenna configuration is wider than the beam width of the antenna configuration to which the actual CBSR is applied, the setting can be instructed to restrict the narrow beams (SD basis) of the actual antenna configuration that overlap with the wide beam (SD basis).

[0206] Figures 14 to 16 illustrate examples of CBSR for cases where the size of the bitmap (X1, X2) is set based on the reference antenna configuration.

[0207] Fig. 14 shows a case where a 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) is configured based on a reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4). The reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4) is set / defined as the reference antenna configuration. Fig. 14(a) is a bitmap for CBSR, which is configured based on the reference antenna configuration (N1=4, N2=4, O1=4, O2=4). Referring to Fig. 14(b), three overlapping SD basis are restricted for the CBSR indication bit of the bitmap (a). In addition, it shows the result of taking a wrap around (e.g., modulo N1*N2*O1*O2) for those exceeding the index.

[0208] Fig. 15 shows a case where a 128port CSI-RS (N1=8, N2=8, O1=4, O2=4) is configured based on a reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4). The reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4) is set / defined as the reference antenna configuration. Fig. 15 (a) is a bitmap for CBSR, which is configured based on the reference antenna configuration (N1=4, N2=4, O1=4, O2=4). Five adjacent beams are restricted for the CBSR for one reference configuration (32 ports). Since the antenna configurations for both N1 and N2 domains differ by a factor of 2, three overlapping SD basis indices (a total of five SD basis since the middle basis is common) are restricted for each of the two domains.

[0209] Fig. 16 shows a case where a 128port CSI-RS (N1=16, N2=4, O1=4, O2=4) is configured based on a reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4). The reference 32port CSI-RS (N1=4, N2=4, O1=4, O2=4) is set / defined as the reference antenna configuration, and it is assumed that the bitmap for CBSR in Fig. 16 is configured in the same way as in Fig. 14 (a) or Fig. 15 (a). Five adjacent beams are restricted for CBSR for one reference configuration (32 ports). Since the antenna configuration for the N1 domain differs by a factor of 4, five overlapping SD basis indices are restricted for each N1 domain.

[0210] Proposal 1 and Method 2 used the implicit method as an example, but in the case of pre-defined patterns, multiple patterns such as 1-by-4 or 2-by-2 can be set and then explicitly signaled separately.

[0211] Proposal 2

[0212] For example, when reporting CSI in NR (e.g., Type I CSI or Type II CSI), the following two-step approach can be considered for CBSR.

[0213] (1) Step 1: Using the 1st bitmap, N1*N2*O1*O2 SD basis indices are designated / set to Y areas where CBSR is performed. Here, the SD basis of each area can include the same number (Z).

[0214] (2) Step 2

[0215] - Option 1: Set CBSR based on Y-bitmap.

[0216] - Option 2: Set CBSR with Z-bit, and apply the same to the area indicated by the 1st step CBSR Y bit.

[0217] - Option 3: In the 1st step, set the maximum number that can be indicated by Y-bit (e.g., W), and in the 2nd step, perform W*Z bit CBSR.

[0218] Figure 17 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 1 of proposal 2.

[0219] Referring to Fig. 17, based on the 1st step, the N1 and / or N2 domain bitmaps can be set. The N1 and / or N2 domain bitmaps are 32 bit-maps and 16 bit-maps, respectively, and for the intersection of the bitmaps of the two domains, the CBSR is set to the 2nd step bitmap (Y=84, Z=1, 12*7=84). The SD basis mapping of the bitmap of the 2nd step can be agreed upon in advance (e.g., N1 first mapping) or can be set separately by the base station.

[0220] In the example of Fig. 17, a total of 64+84=148 bits are used for CBSR, which can significantly reduce the number of bits required compared to the existing 512-bit map. If a bitmap for a specific domain is not set among the 1st step bitmaps, it can be agreed that all SD indices corresponding to that domain will be included to form the bitmap.

[0221] Fig. 18 illustrates another example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 1 of proposal 2.

[0222] The division into Y partitions in the 1st step can be set based on implicit rules. For example, it can be set / instructed to select only even or odd indices in the N1 and / or N2 domains, or to select with a specific step size and / or offset value (e.g., every 4 indices, with an offset value (e.g., 0, 1, 2, 3)).

[0223] Referring to Fig. 18, Y zones of the 1st step are set based on the step size 4 for the N1 domain and the step size 2 (even number) for the N2 domain, and the final CBSR is set / indicated with the Y-bitmap of the 2nd step. Here, the offset value of each domain is assumed to be 0.

[0224] Figure 19 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 2 of proposal 2.

[0225] Referring to Fig. 19, the Y value is 32 bits, and the 1st bitmap represents information about the area to which restriction is applied with 32 bits, and one area is composed of Z=16 SD indices. In the case of the area indicated as blank in Fig. 19(c), it can be understood as an SD index that is not restricted by CBSR (same effect as being indicated by "1" in the bitmap). If the method of option 2 is used, CBSR can be performed with a total of 32+16 = 48 bits. The number of CBSR bits (including the size of the Y-bitmap in the 1st step and / or the Z-bitmap in the 2nd step) can be agreed in advance or separately signaled by the base station. The SD basis mapping of the bitmap in the 2nd step can be agreed in advance (e.g., N1 first mapping) or separately set by the base station.

[0226] Figure 20 illustrates an example of CBSR for 64port CSI-RS (N1=8, N2=4, O1=4, O2=4) according to option 3 of proposal 2.

[0227] Referring to Fig. 20, the Y value is 32 bits, and the 1st bitmap represents information about the area to which restriction is applied with 32 bits. Here, the maximum number of “0” that can be set to the 1st bitmap is W=10, and Z=16 is considered. In the 2nd step, CBSR can be performed with W*Z=10*16 = 160 bit-maps to indicate / set the restricted SD basis. If the method of option 3 is used, CBSR can be performed with a total of 32+160 = 198 bits. The number of CBSR bits (including the Y-bitmap and / or W size in the 1st step) can be agreed in advance or separately signaled by the base station. The above option 3 can be considered a special case of option 2. The SD basis mapping of the bitmap of the 2nd step can be agreed in advance (e.g., N1 first mapping) or separately set by the base station.

[0228] Proposal 3

[0229] When reporting multiple CRI-based CSI in NR (e.g., Type I CSI or Type II CSI), CBSR can be group-commonly set / indicated for multiple CMR and / or IMR pairs.

[0230] For example, let's assume that K 32-port CSI-RS resources are configured. Here, for convenience, let's assume 1 IMR. Then, the terminal selects multiple resources based on CRI among the K CSI-RS resources and reports M CSIs (CRI, RI, CQI, PMI) to the terminal. When reporting CSI based on these multiple CRIs, CBSR can be configured to be applied commonly to all resources, but since interference to other cells may differ depending on the beam information (CMR and / or IMR) formed by the base station, CBSR configuration for each CMR (and / or IMR) may be required for more flexible configuration. However, if CBSR is configured for all K resources, RRC overhead may be excessive, so it can be agreed that the CBSR is configured for each CMR (and / or IMR) group. For the above K CMRs (and / or IMRs), G groups can be agreed upon in advance or designated through RRC settings, etc., and CBSR is designated / designated for each of the G groups. Then, the terminal does not include the SD basis designated as CBSR in the CSI calculation / report corresponding to the CMR (and / or IMR) based on the CBSR designated for each CMR (and / or IMR) group.

[0231] In the above proposals 1 / 2 / 3, the bitmap is represented as a 2D bitmap for convenience of explanation, but since a 1D bitmap can also perform the same function, it can also be set / indicated as a 1D bitmap. In this case, the 1D bitmap can be expressed and indicated in the N1 first mapping (or N2 first mapping) manner in the example of the 2D bitmap above. For example, the bits corresponding to N2 index 0 (i.e., (N1, N2)=(0,0), (1,0), (2,0), .... (N1O1,0)) of the 2D bitmap first occupy the MSB, and the bits corresponding to N2 index 1 (i.e., (N1, N2)=(0,1), (1,1), (2,1), .... (N1O1,1)) occupy the next, and so on. For N2 first mapping, bits corresponding to N1 index 0 (i.e., (N1, N2)=(0,0), (0,1), (0,2), .... (0,N1O1)) of the 2D bitmap are mapped in the order of MSB first, followed by bits corresponding to N1 index 1 (i.e., (N1, N2)=(1,0), (1,1), (1,2), .... (1,N1O1)).

[0232] The above suggestions 1 / 2 / 3 can be implemented alone or in combination.

[0233] Fig. 21 is a diagram illustrating the operation of a terminal and a network according to one embodiment. Some parts of the terminal / network operation of Fig. 21 may be omitted depending on the embodiment.

[0234] Referring to FIG. 21, a terminal may transmit a UE capability report to the network via upper layer signaling (2105). The UE Capability report may include, but is not limited to, at least one of the maximum number of CSI-RS resources / maximum number of CSI-RS ports that the terminal can support, the total number of CSI-RS ports that can be simultaneously supported, and / or the number of Rx antenna groups.

[0235] The terminal may receive configuration information related to CSI RS transmission and / or CSI reporting from the network (2110). The configuration information may include configuration information for CBSR.

[0236] The terminal can receive CSI-RS(s) from the base station (2115) and measure / predict / calculate CSI (2120). When calculating / reporting CSI for the terminal, the SD basis indicated as CBSR is not used for CSI calculation / reporting.

[0237] The terminal can report measured / predicted / calculated CSI to the base station (2125).

[0238] The terminal can receive information for scheduling a downlink channel (e.g., PDCCH, PDSCH) from the base station (2130).

[0239] The terminal can receive a scheduled downlink channel (e.g., PDCCH, PDSCH) (2135).

[0240] FIG. 22 illustrates a flow of a method performed by a terminal according to one embodiment.

[0241] Referring to FIG. 22, the terminal can receive configuration information for CBSR (codebook subset restriction) through upper layer signaling (2205).

[0242] The terminal can determine a precoder subset within a codebook containing a plurality of precoders based on the configuration information for the CBSR (2210).

[0243] The terminal can receive a CSI-RS (channel state information-reference signal) (2215).

[0244] The terminal can transmit a CSI report based on the precoder subset and the CSI-RS (2220).

[0245] The above CSI-RS can be transmitted through more than 32 antenna ports.

[0246] The configuration information for the CBSR may include (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain, and (ii) information about X1 and X2. The number M of precoder components associated with each bit of the bitmap may be determined based on X1 and X2.

[0247] The above M is determined based on N1*O1 / X1 and N2*O2 / X2, where the N1 and the O1 may be the number of antennas and the first oversampling factor in the first domain, respectively, and the N2 and the O2 may be the number of antennas and the second oversampling factor in the second domain, respectively.

[0248] The above M can be (N1*O1 / X1) * (N2*O2 / X2).

[0249] Multiple groups can be set based on the above X1 and X2.

[0250] Each group can contain M precoder components.

[0251] Whether CBSR is applied to each group can be determined based on whether the value of each bit of the above bitmap is 0 or 1.

[0252] The precoder subset can be determined based on at least one group to which the CBSR does not apply.

[0253] The above bitmap may contain X1*X2 bits.

[0254] The above precoder components may be SD (spatial domain) basis vectors.

[0255] The above codebook may be a Type I codebook or a Type II codebook.

[0256] The above CSI-RS can be transmitted through 48, 64 or 128 antenna ports.

[0257] FIG. 23 illustrates a flow of a method performed by a base station according to one embodiment.

[0258] Referring to FIG. 23, a base station can determine a precoder subset within a codebook containing multiple precoders (2305).

[0259] The base station can transmit configuration information for CBSR (codebook subset restriction) to the terminal through upper layer signaling based on the determined precoder subset (2310).

[0260] The base station can transmit a CSI-RS (channel state information-reference signal) to the terminal (2315).

[0261] The base station can receive a CSI report from the terminal (2320).

[0262] The CSI-RS is transmitted through more than 32 antenna ports, and the configuration information for the CBSR includes (i) a bitmap having X1 bits for a first domain and X2 bits for a second domain, and (ii) information about the X1 and the X2, and the number M of precoder components associated with each bit of the bitmap can be determined based on the X1 and X2.

[0263] The above M is determined based on N1*O1 / X1 and N2*O2 / X2, where the N1 and the O1 may be the number of antennas and the first oversampling factor in the first domain, respectively, and the N2 and the O2 may be the number of antennas and the second oversampling factor in the second domain, respectively.

[0264] The above M can be (N1*O1 / X1) * (N2*O2 / X2).

[0265] Multiple groups can be set based on the above X1 and X2.

[0266] Each group can contain M precoder components.

[0267] Whether CBSR is applied to each group can be indicated based on whether the value of each bit of the above bitmap is 0 or 1.

[0268] The above bitmap may contain X1*X2 bits.

[0269] The above precoder components may be SD (spatial domain) basis vectors.

[0270] The above codebook may be a Type I codebook or a Type II codebook.

[0271] The above CSI-RS can be transmitted through 48, 64 or 128 antenna ports.

[0272] Fig. 24 illustrates a communication system (1) applicable to the present disclosure.

[0273] Referring to FIG. 24, a communication system (1) includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and can be implemented in the form of HMD (Head-Mounted Device), HUD (Head-Up Display) installed in a vehicle, television, smartphone, computer, wearable device, home appliance, digital signage, vehicle, robot, etc. Mobile devices can include smartphone, smart pad, wearable device (e.g., smart watch, smart glass), computer (e.g., laptop, etc.), etc. Home appliances can include TV, refrigerator, washing machine, etc. IoT devices can include sensors, smart meters, etc. For example, base stations and networks can also be implemented as wireless devices, and a specific wireless device (200a) can act as a base station / network node to other wireless devices.

[0274] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0275] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base stations (200), and base stations (200) / base stations (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or, D2D communication), and communication between base stations (150c) (e.g., relay, IAB (Integrated Access Backhaul). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of the present invention.

[0276] Figure 25 illustrates a wireless device applicable to the present disclosure.

[0277] Referring to FIG. 25, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the base station (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 24.

[0278] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (102) may process information in the memory (104) to generate first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver (106). In addition, the processor (102) may receive a wireless signal including second information / signal via the transceiver (106), and then store information obtained from signal processing of the second information / signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present invention, a wireless device may also mean a communication modem / circuit / chip.

[0279] The second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present invention, a wireless device may also mean a communication modem / circuit / chip.

[0280] Hereinafter, the hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed herein, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed herein.

[0281] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). The descriptions, functions, procedures, suggestions, methods and / or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0282] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0283] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of this document, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of this document, from one or more other devices. For example, one or more transceivers (106, 206) can be connected to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed herein, via one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0284] Figure 26 illustrates another example of a wireless device applicable to the present invention. The wireless device may be implemented in various forms depending on the use case / service (see Figure 24).

[0285] Referring to FIG. 26, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 25 and may be composed of various elements, components, units / units, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and an additional element (140). The communication unit may include a communication circuit (112) and a transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 25. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 25. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0286] The additional element (140) may be configured in various ways depending on the type of the wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 24, 100a), a vehicle (Fig. 24, 100b-1, 100b-2), an XR device (Fig. 24, 100c), a portable device (Fig. 24, 100d), a home appliance (Fig. 24, 100e), an IoT device (Fig. 24, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 24, 400), a base station (Fig. 24, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0287] In FIG. 26, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and a first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of a set of one or more processors. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0288] Figure 27 illustrates a vehicle or autonomous vehicle applicable to the present disclosure. The vehicle or autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned or unmanned aerial vehicle (AV), a ship, or the like.

[0289] Referring to FIG. 27, a vehicle or autonomous vehicle (100) may include an antenna unit (108), a communication unit (110), a control unit (120), a driving unit (140a), a power supply unit (140b), a sensor unit (140c), and an autonomous driving unit (140d). The antenna unit (108) may be configured as a part of the communication unit (110). Blocks 110 / 130 / 140a to 140d correspond to blocks 110 / 130 / 140 of FIG. 26, respectively.

[0290] The communication unit (110) can transmit and receive signals (e.g., data, control signals, etc.) with external devices such as other vehicles, base stations (e.g., base stations, road side units, etc.), and servers. The control unit (120) can control elements of the vehicle or autonomous vehicle (100) to perform various operations. The control unit (120) can include an ECU (Electronic Control Unit). The drive unit (140a) can drive the vehicle or autonomous vehicle (100) on the ground. The drive unit (140a) can include an engine, a motor, a power train, wheels, brakes, a steering device, etc. The power supply unit (140b) supplies power to the vehicle or autonomous vehicle (100) and can include a wired / wireless charging circuit, a battery, etc. The sensor unit (140c) can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit (140c) may include an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an incline sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit (140d) may implement a technology for maintaining a driving lane, a technology for automatically controlling speed such as adaptive cruise control, a technology for automatically driving along a set path, a technology for automatically setting a path and driving when a destination is set, etc.

[0291] For example, the communication unit (110) can receive map data, traffic information data, etc. from an external server. The autonomous driving unit (140d) can generate an autonomous driving route and driving plan based on the acquired data. The control unit (120) can control the drive unit (140a) so that the vehicle or autonomous vehicle (100) moves along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit (110) can irregularly / periodically acquire the latest traffic information data from an external server and can acquire surrounding traffic information data from surrounding vehicles. In addition, during autonomous driving, the sensor unit (140c) can acquire vehicle status and surrounding environment information. The autonomous driving unit (140d) can update the autonomous driving route and driving plan based on newly acquired data / information. The communication unit (110) can transmit information regarding the vehicle location, autonomous driving route, driving plan, etc. to the external server. External servers can predict traffic information data in advance using AI technology or other technologies based on information collected from vehicles or autonomous vehicles, and provide the predicted traffic information data to the vehicles or autonomous vehicles.

[0292] The embodiments described above are combinations of components and features of the present invention in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form an embodiment of the present invention by combining some components and / or features. The order of operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form an embodiment or may be incorporated as a new claim through a post-application amendment.

[0293] It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the scope of the invention. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present invention are intended to be included within the scope of the present invention.

[0294] The present disclosure may be used in a terminal, base station, or other equipment of a wireless mobile communication system.

Claims

1. In a method performed by a terminal, Receive configuration information for CBSR (codebook subset restriction) through upper layer signaling; Determine a subset of precoders within a codebook containing multiple precoders based on configuration information for the CBSR; Receiving CSI-RS (channel state information-reference signal); and Including transmitting a CSI report based on the precoder subset and the CSI-RS, The above CSI-RS is transmitted through more than 32 antenna ports, The configuration information for the CBSR includes (i) a bitmap having X1 bits for the first domain and X2 bits for the second domain, and (ii) information about the X1 and the X2, A method in which the number M of precoder components associated with each bit of the above bitmap is determined based on X1 and X2.

2. In paragraph 1, The above M is determined based on N1*O1 / X1 and N2*O2 / X2, A method wherein the N1 and the O1 are the number of antennas and the first oversampling factor in the first domain, respectively, and the N2 and the O2 are the number of antennas and the second oversampling factor in the second domain, respectively.

3. In paragraph 2, The above M is (N1*O1 / X1) * (N2*O2 / X2).

4. In paragraph 1, A method wherein the above bitmap contains X1*X2 bits.

5. In paragraph 1, A plurality of groups are set based on the above X1 and X2, A method wherein each group contains M precoder components.

6. In paragraph 5, Whether CBSR is applied to each group is determined based on whether the value of each bit of the above bitmap is 0 or 1. A method wherein the precoder subset is determined based on at least one group to which the CBSR does not apply.

7. In paragraph 1, The above precoder components are SD (spatial domain) basis vectors.

8. In paragraph 1, The above codebook is a Type I codebook or a Type II codebook.

9. In paragraph 1, A method wherein the above CSI-RS is transmitted through 48, 64 or 128 antenna ports.

10. A non-transitory computer-readable recording medium having recorded thereon a program for performing the method described in paragraph 1.

11. In the device, a memory configured to store instructions; and A processor configured to perform operations by executing the above instructions, The operations of the above processor are: Receive configuration information for CBSR (codebook subset restriction) through upper layer signaling; Determine a subset of precoders within a codebook containing multiple precoders based on configuration information for the CBSR; Receiving CSI-RS (channel state information-reference signal); and Including transmitting a CSI report based on the precoder subset and the CSI-RS, The above CSI-RS is transmitted through more than 32 antenna ports, The configuration information for the CBSR includes (i) a bitmap having X1 bits for the first domain and X2 bits for the second domain, and (ii) information about the X1 and the X2, The number M of precoder components associated with each bit of the above bitmap is determined based on X1 and X2, the device.

12. In paragraph 11, Including a transmitter and receiver, The above device is a terminal in a wireless communication system.

13. In paragraph 11, The above device is a processing device configured to control a terminal in a wireless communication system.

14. In a method performed by a base station, Determine a subset of precoders within a codebook containing multiple precoders; Based on the above-determined precoder subset, setting information for CBSR (codebook subset restriction) is transmitted to the terminal through upper layer signaling; Transmitting CSI-RS (channel state information-reference signal) to the terminal; and Including receiving a CSI report from the terminal, The above CSI-RS is transmitted through more than 32 antenna ports, The configuration information for the CBSR includes (i) a bitmap having X1 bits for the first domain and X2 bits for the second domain, and (ii) information about the X1 and the X2, A method in which the number M of precoder components associated with each bit of the above bitmap is determined based on X1 and X2.

15. At the base station, a memory configured to store instructions; and A processor configured to perform operations by executing the above instructions, The operations of the above processor are: Determine a subset of precoders within a codebook containing multiple precoders; Based on the above-determined precoder subset, setting information for CBSR (codebook subset restriction) is transmitted to the terminal through upper layer signaling; Transmitting CSI-RS (channel state information-reference signal) to the terminal; and Including receiving a CSI report from the terminal, The above CSI-RS is transmitted through more than 32 antenna ports, The configuration information for the CBSR includes (i) a bitmap having X1 bits for the first domain and X2 bits for the second domain, and (ii) information about the X1 and the X2, The number M of precoder components associated with each bit of the above bitmap is determined based on X1 and X2.

Images