Method and apparatus for transmitting channel state information for multiple time instances in a wireless communication system

Abstract

The present invention relates to a method performed by a User Equipment (UE) in a wireless communication system, the method comprising: receiving a control signal for reporting Channel Status Information (CSI) from a Base Station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the control signal; calculating at least one Precoding Matrix Index (PMI) for at least one time instance based on the at least one CMR using a Time Domain Compressed (TD) codebook; and transmitting the CSI to the BS, the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant resource included in the control signal, wherein the plurality of NZCs have priority values determined by considering a time domain (TD) basis vector index, a frequency domain (FD) basis vector index, a spatial domain (SD) basis vector index, and a layer index in that order.

Description

[Technical Field]

[0001] The present invention relates to wireless communication systems, and more particularly to a method and apparatus for transmitting channel state information for multiple time instances in a wireless communication system. [Background technology]

[0002] Wireless communication systems have been widely deployed to provide various communication services such as voice and data. Generally, wireless communication systems are multiple access systems that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single carrier frequency division multiple access (SC-FDMA) systems. Summary of the Invention [Problem to be solved by the invention]

[0003] Based on the above discussion, the following will propose a method and apparatus for transmitting channel state information for multiple time instances in a wireless communication system.

[0004] The technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a method performed by a User Equipment (UE) in a wireless communication system, the method including: receiving a control signal for reporting Channel Status Information (CSI) from a Base Station (BS), receiving at least one channel measurement resource (CMR) from the BS based on the control signal, calculating at least one Precoding Matrix Index (PMI) for at least one time instance using a Time Domain Compressed (TD) codebook based on the at least one CMR, and transmitting the CSI to the BS, the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant resource included in the control signal, wherein the plurality of NZCs have priority values ​​determined by considering a time domain (TD) basis vector index, a frequency domain (FD) basis vector index, a spatial domain (SD) basis vector index, and a layer index in that order.

[0006] In another aspect of the present invention, there is provided User Equipment (UE) in a wireless communication system, the user equipment including at least one transceiver, at least one processor, and at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The operations include receiving a control signal for reporting Channel Status Information (CSI) from a Base Station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the control signal; calculating at least one Precoding Matrix Index (PMI) for at least one time instance based on the at least one CMR using a Time domain compressed (TD) codebook; and transmitting the CSI to the BS, including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI, based on an uplink grant resource included in the control signal, wherein the plurality of NZCs have priority values ​​determined by considering a time domain (TD) basis vector index, a frequency domain (FD) basis vector index, a spatial domain (SD) basis vector index, and a layer index in that order.

[0007] In yet another aspect of the present invention, there is provided a processing device in a wireless communication system, the processing device including at least one processor and at least one computer memory operatively coupled to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations for a user equipment (UE). The operations include receiving a control signal for reporting Channel Status Information (CSI) from a Base Station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the control signal; calculating at least one Precoding Matrix Index (PMI) for at least one time instance based on the at least one CMR using a Time domain compressed (TD) codebook; and transmitting the CSI to the BS, the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant resource included in the control signal, wherein the plurality of NZCs have priority values ​​determined by considering a time domain (TD) basis vector index, a frequency domain (FD) basis vector index, a spatial domain (SD) basis vector index, and a layer index in that order.

[0008] In yet another aspect of the present invention, a computer-readable storage medium is provided that stores at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform an operation for a user equipment (UE). The operations include receiving a control signal for reporting Channel Status Information (CSI) from a Base Station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the control signal; calculating at least one Precoding Matrix Index (PMI) for at least one time instance based on the at least one CMR using a Time domain compressed (TD) codebook; and transmitting the CSI to the BS, the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant resource included in the control signal, wherein the plurality of NZCs have priority values ​​determined by considering a time domain (TD) basis vector index, a frequency domain (FD) basis vector index, a spatial domain (SD) basis vector index, and a layer index in that order.

[0009] In each aspect of the present invention, the multiple NZCs have a higher priority value the larger the index of the TD basis vector, and when the indices of the TD basis vectors are the same, the larger the index of the FD basis vector, the higher the priority value, and when the indices of the TD basis vectors and the FD basis vectors are the same, the larger the index of the SD basis vector, the higher the priority value, and when the indices of the TD basis vectors, the FD basis vectors and the SD basis vectors are the same, the larger the layer index, the higher the priority value.

[0010] In each aspect of the present invention, the priority of an NZC in which the layer index is l, the SD basis vector index is i, the FD basis vector index is f, and the TD basis vector index is t is determined by the following formula:

[0011] Formula

number

[0012] (where υ is the number of layers, 2L is the number of SD basis vectors, N3 is a value related to the number of FD basis vectors, and π'(t) is a function that transforms the index of the TD basis vectors.)

[0013] In each aspect of the present invention, if the uplink grant resource is smaller than the CSI payload, the UE drops at least one NZC from the plurality of NZCs in descending order of priority value assigned to the plurality of NZCs.

[0014] In each aspect of the present invention, the maximum number of NZCs per layer is determined based on a product of the number of TD basis vectors, the number of FD basis vectors, the number of SD basis vectors, and a constant greater than 0 and less than or equal to 1.

[0015] The above-described solutions to problems are merely some of the embodiments of the present invention, and various embodiments reflecting the technical features of the present invention will be understood and derived by those skilled in the art based on the detailed description of the present invention below. [Effects of the Invention]

[0016] According to the present invention, it is possible to efficiently transmit and receive radio signals in a radio communication system.

[0017] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0018] The accompanying drawings, which are included as part of the detailed description to aid in the understanding of embodiments of the present invention, provide examples of the invention and, together with the detailed description, explain embodiments of the invention.

[0019] [Figure 1] 1 is a diagram illustrating physical channels used in a 3GPP (registered trademark) system, which is an example of a wireless communication system, and a general signal transmission method using these channels. [Figure 2] FIG. 1 is a diagram illustrating the structure of a radio frame. [Figure 3] FIG. 1 illustrates a resource grid of slots. [Figure 4] FIG. 10 is a diagram illustrating an example of mapping physical channels within a slot. [Figure 5] FIG. 1 illustrates a PDSCH and ACK / NACK transmission process. [Figure 6] FIG. 1 illustrates a PUSCH transmission process. [Figure 7] FIG. 1 illustrates an example of a CSI-related procedure. [Figure 8]This is a diagram for explaining the concepts of AI / ML / deep learning. [Figure 9] This figure illustrates various AI / ML models of deep learning. [Figure 10] This figure illustrates various AI / ML models of deep learning. [Figure 11] This figure illustrates various AI / ML models of deep learning. [Figure 12] This figure illustrates various AI / ML models of deep learning. [Figure 13] FIG. 1 is a diagram illustrating a framework for 3GPP RAN Intelligence. [Figure 14] FIG. 1 illustrates an example of reporting PMI for multiple time instances. [Figure 15] FIG. 1 illustrates an example of reporting PMI for multiple time instances. [Figure 16] 1 is a flowchart illustrating a method for reporting CSI for multiple time instances according to the present disclosure. [Figure 17] 1 is a diagram illustrating a communication system 1 and wireless devices applicable to the present invention. [Figure 18] 1 is a diagram illustrating a communication system 1 and wireless devices applicable to the present invention. [Figure 19] 1 is a diagram illustrating a communication system 1 and wireless devices applicable to the present invention. [Figure 20] 1 is a diagram illustrating a communication system 1 and wireless devices applicable to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following technologies can be used for various wireless access systems, such as 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). CDMA can be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. TDMA can be implemented using radio technologies such as Global System for Mobile communications (GSM), General Packet Radio Service (GPRS), and Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented using radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) LTE (long term evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A is an evolved version of 3GPP LTE. 3GPP NR (New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A.

[0021] As more communication devices require larger communication capacities, there is an emerging need for improved mobile broadband communication compared to existing radio access technologies (RATs). Furthermore, massive machine-type communications (MTC), which connects multiple devices and objects to provide various services anytime, anywhere, is one of the important issues to be considered in next-generation communications. Furthermore, communication system designs that take into account reliability- and latency-sensitive services / terminals are being discussed. Thus, the introduction of next-generation RATs that take into account enhanced mobile broadband communication (eMBB), massive MTC, and ultra-reliable and low latency communication (URLLC) is being discussed. For convenience, the present invention refers to these technologies as new radio or new RATs (NR).

[0022] For clarity of explanation, the description will be focused on 3GPP NR, but the technical idea of ​​the present invention is not limited thereto.

[0023] In this specification, the term "setting" may be replaced with the term "configure / configuration," and the two terms may be used interchangeably. Conditional expressions (e.g., "if," "in a case," or "when") may be replaced with expressions such as "based on that" or "in a state / status." The operation or SW / HW configuration of a terminal / base station based on the satisfaction of a corresponding condition may be inferred or understood by analogy. In signal transmission and reception between wireless communication devices (e.g., base station, terminal), if the process on the receiving (or transmitting) side can be inferred or understood from the process on the transmitting (or receiving) side, the explanation may be omitted. For example, the signal determination / generation / encoding / transmission on the transmitting side may be understood as the signal monitoring / reception / decoding / decision on the receiving side. An expression that a terminal performs (or does not perform) a specific operation may also be interpreted as the base station operating by expecting / assuming (or expecting / assuming not) that the terminal will perform the specific operation. An expression that a base station performs (or does not perform) a specific operation can also be interpreted as a terminal operating under the expectation / assuming (or expecting / assuming not to perform) the execution of a specific operation of the base station. Furthermore, in the following description, divisions and indexes for each section, embodiment, example, option, method, solution, etc. are for the convenience of explanation and should not be interpreted as meaning that each necessarily constitutes an independent invention or that each necessarily must be implemented individually. Furthermore, in describing each section, embodiment, example, option, method, solution, etc., unless explicitly stated to conflict or contradict, it can be inferred / interpreted that at least some of them may be combined and implemented together, or at least some may be omitted and implemented.

[0024] In a wireless communication system, a terminal receives information from a base station via a downlink (DL), and transmits information from the base station via an uplink (UL). Information exchanged between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information exchanged.

[0025] FIG. 1 is a diagram illustrating physical channels used in a 3GPP system and a general signal transmission method using these channels.

[0026] A terminal that has been powered on in a powered-off state or that has newly entered a cell performs an initial cell search, such as establishing synchronization with a base station (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). The terminal establishes synchronization with the base station based on the PSS / SSS and obtains information such as a cell identity. The terminal also obtains broadcast information within the cell based on the PBCH. In addition, during the initial cell search phase, the terminal can receive a downlink reference signal (DL RS) to check the status of the downlink channel.

[0027] After completing the initial cell search, the terminal receives a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) corresponding to the physical downlink control channel to obtain more specific system information (S102).

[0028] Thereafter, the terminal performs a random access procedure to complete connection to the base station (S103 to S106). More specifically, the terminal transmits a preamble over a physical random access channel (PRACH) (S103) and receives a response message to the preamble over a physical downlink control channel (PRACH) and a corresponding physical downlink shared channel (S104). In the case of contention-based random access, the terminal performs a contention resolution procedure, such as transmitting a further physical random access channel (S105) and receiving a physical downlink control channel and a corresponding physical downlink shared channel (S106).

[0029] After performing this procedure, the terminal then receives a physical downlink control channel / physical downlink shared channel (S107) and transmits a physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) (S108) as a general uplink / downlink signal transmission procedure. Control information transmitted by the terminal to the base station is 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 via PUCCH, but may be transmitted via PUSCH when control information and traffic data need to be transmitted simultaneously. In addition, the UE may aperiodically transmit UCI via PUSCH at the request / instruction of the network.

[0030] FIG. 2 illustrates the structure of a radio frame. In NR, uplink and downlink transmissions are organized into frames. A radio frame has a length of 10 ms and is divided into two 5 ms half-frames (HF). A half-frame is divided into five 1 ms subframes (SF). A subframe is divided into one or more slots, and the number of slots in a subframe depends on the subcarrier spacing (SCS). Each slot contains 12 or 14 orthogonal frequency division multiplexing (OFDM) 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.

[0031] Table 1 shows the number of OFDM symbols per slot (N slot symb ), number of slots per frame (N frame,u slot ) and the number of slots per subframe (N subframe,u slot )

[0032] [Table 1]

[0033] Table 2 shows the number of OFDM symbols per slot (N slot symb ), number of slots per frame (N frame,u slot ) and the number of slots per subframe (N subframe,u slot )

[0034] [Table 2]

[0035] The frame structure is illustrative only, and the number of subframes, slots, and symbols in a frame can vary.

[0036] In an NR system, OFDM numerology (e.g., SCS) can be configured to be different among multiple cells merged into one terminal. Accordingly, the (absolute time) duration of time resources (e.g., SF, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) consisting of the same number of symbols can be configured to be different among the merged cells. Here, the symbols include OFDM symbols (or CP-OFDM symbols) and SC-FDMA symbols (or Discrete Fourier Transform-spread-OFDM, DFT-s-OFDM symbols).

[0037] FIG. 3 illustrates a resource grid of a slot. One slot includes multiple symbols in the time domain. For example, in the case of a general CP, one slot includes 14 symbols, while in the case of an extended CP, one slot includes 12 symbols. A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) is defined by multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) is defined by multiple consecutive physical RBs (PRBs) in the frequency domain and can correspond to one numerology (e.g., SCS, CP length, etc.). A carrier includes up to N (e.g., 5) BWPs. Data communication is performed using activated BWPs, and only one BWP can be activated for one terminal. Each element in the resource grid is called a resource element (RE), and one modulation symbol can be mapped to it.

[0038] Figure 4 shows an example of mapping physical channels within a slot. PDCCH is transmitted in the DL control region, and PDSCH is transmitted in the DL data region. PUCCH is transmitted in the UL control region, and PUSCH is transmitted in the UL data region. GP provides a time gap when the base station and the terminal switch from transmission mode to reception mode or from reception mode to transmission mode. Some symbols at the time of switching from DL to UL within a subframe can be set as GP.

[0039] Each physical channel will be described in more detail below.

[0040] 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 higher layer control messages such as voluntary access responses transmitted on the PDSCH, transmit power control commands, and activation / deactivation of configured scheduling (CS). 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 use 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 related to paging, the CRC is masked with a Paging-RNTI (P-RNTI). If the PDCCH is related to system information (e.g., System Information Block, SIB), the CRC is masked with a System Information RNTI (SI-RNTI). If the PDCCH is related to an voluntary access response, the CRC is masked with a Random Access RNTI (RA-RNTI).

[0041] 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 according to the radio channel condition. A CCE consists of 6 Resource Element Groups (REGs). A REG is defined by one OFDM symbol and one (P)RB. The PDCCH is transmitted using a Control Resource Set (CORESET). A CORESET is defined by a set of REGs with a given pneumatic system (e.g., SCS, CP length, etc.). Multiple CORESETs for one UE can be overlapped in the time / frequency domain. A CORESET is configured by system information (e.g., Master Information Block, MIB) or UE-specific higher layer (e.g., Radio Resource Control, RRC, layer) signaling. Specifically, the number of RBs and the number of OFDM symbols (maximum 3) that make up a CORESET are configured by higher layer signaling.

[0042] To receive / detect the PDCCH, the UE monitors PDCCH candidates. PDCCH candidates indicate the CCEs that the UE should monitor for PDCCH detection. Each PDCCH candidate is defined by 1, 2, 4, 8, or 16 CCEs depending on the AL. Monitoring includes (blind) decoding of the PDCCH candidates. The set of PDCCH candidates that the UE monitors is defined as the PDCCH search space (SS). The search space includes a common search space (CSS) or a UE-specific search space (USS). The UE can obtain DCI by monitoring PDCCH candidates in one or more search spaces configured by 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 is defined based on the following parameters:

[0043] - controlResourceSetId: Indicates the CORESET associated with the search space.

[0044] - monitoringSlotPeriodicityAndOffset: Indicates the PDCCH monitoring period (in slot units) and the PDCCH monitoring period offset (in slot units).

[0045] - monitoringSymbolsWithinSlot: indicates the PDCCH monitoring symbols within the slot (for example, indicates the first symbol of CORESET).

[0046] - nrofCandidates: indicates the number of PDCCH candidates (one of 0, 1, 2, 3, 4, 5, 6, 8) for each AL={1, 2, 4, 8, 16}.

[0047] *An opportunity (e.g., time / frequency resource) for monitoring a PDCCH candidate is defined as a PDCCH (monitoring) opportunity. One or more PDCCH (monitoring) opportunities are configured within a slot.

[0048] Table 3 illustrates the characteristics of each search space type.

[0049] [Table 3]

[0050] Table 4 illustrates DCI formats transmitted via the PDCCH.

[0051] [Table 4]

[0052] DCI format 0_0 is used to schedule a TB-based (or TB-level) PUSCH, and DCI format 0_1 ​​is used to schedule a TB-based (or TB-level) PUSCH or a Code Block Group (CBG)-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 is used to schedule a TB-based (or TB-level) PDSCH or a CBG-based (or CBG-level) PDSCH (DL grant DCI). DCI formats 0_0 / 0_1 are referred to as UL grant DCI or UL scheduling information, and DCI formats 1_0 / 1_1 are 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 a UE, and DCI format 2_1 is used to convey downlink pre-emption information to a UE. DCI format 2_0 and / or DCI format 2_1 are transmitted to terminals in a corresponding group via a group common PDCCH, which is a PDCCH transmitted to terminals defined in one group.

[0053] DCI format 0_0 and DCI format 1_0 are called fallback DCI formats, and DCI format 0_1 ​​and DCI format 1_1 are called non-fallback DCI formats. The fallback DCI format maintains the same DCI size / field configuration regardless of the terminal settings. On the other hand, the non-fallback DCI format has different DCI size / field configurations depending on the terminal settings.

[0054] The PDSCH carries downlink data (e.g., DL-SCH transport block, DL-SCH TB) and uses modulation methods such as Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (16QAM), 64QAM, and 256QAM. The TB is encoded to generate a codeword. The PDSCH carries up to two codewords. Scrambling and modulation mapping are performed for each codeword, and the modulation symbols generated from each codeword are 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 from the corresponding antenna port.

[0055] The PUCCH carries Uplink Control Information (UCI), which includes:

[0056] - SR (Scheduling Request): Information used to request UL-SCH resources.

[0057] - HARQ-ACK: A response to a downlink data packet (e.g., a codeword) on the PDSCH. It indicates whether the downlink data packet has been successfully received. One HARQ-ACK bit is transmitted in response to a single codeword, and two HARQ-ACK bits are transmitted in response to two codewords. HARQ-ACK responses include positive ACK (simply referred to as ACK), negative ACK (hereinafter referred to as NACK), DTX (Discontinuous Transmission), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ ACK / NACK and ACK / NACK.

[0058] CSI (Channel State Information): Feedback information for a downlink channel. MIMO (Multiple Input Multiple Output)-related feedback information includes a Rank Indicator (RI) and a Precoding Matrix Indicator (PMI).

[0059] Table 5 shows an example of a PUCCH format. According to the PUCCH transmission length, it can be divided into Short PUCCH (formats 0 and 2) and Long PUCCH (formats 1, 3, and 4).

[0060] [Table 5]

[0061] PUCCH format 0 carries UCI with a maximum size of 2 bits and is mapped and transmitted based on a sequence. Specifically, the terminal transmits one of multiple sequences over a PUCCH with PUCCH format 0 to transmit specific UCI to the base station. The terminal transmits a PUCCH with PUCCH format 0 within the PUCCH resource for the corresponding SR setting only when transmitting a positive SR.

[0062] PUCCH format 1 carries UCI with a maximum size of 2 bits, and modulation symbols are spread in the time domain by an orthogonal cover code (OCC) (which is set differently depending on whether frequency hopping is enabled or disabled). DMRS is transmitted in symbols where no modulation symbols are transmitted (i.e., it is transmitted using TDM (Time Division Multiplexing)).

[0063] PUCCH format 2 carries UCI with a bit size greater than 2 bits, and modulation symbols are transmitted using frequency division multiplexing (FDM) with DM-RS. DM-RS is located at symbol indices #1, #4, #7, and #10 within a 1 / 3 density resource block. A pseudo noise (PN) sequence is used for the DM-RS sequence. Frequency hopping can be enabled for the 2-symbol PUCCH format 2.

[0064] In PUCCH format 3, terminals are not multiplexed within the same physical resource block and UCI with a bit size greater than 2 bits is carried. That is, the PUCCH resources of PUCCH format 3 do not include orthogonal cover codes. Modulation symbols are transmitted using DMRS and TDM (Time Division Multiplexing).

[0065] PUCCH format 4 supports multiplexing of up to four UEs in the same physical resource block and carries UCI with a bit size greater than 2. That is, the PUCCH resource of PUCCH format 3 includes an orthogonal cover code. Modulation symbols are transmitted using DMRS and TDM (Time Division Multiplexing).

[0066] At least one of the one or more configured cells can be configured for PUCCH transmission in the UE. At least a primary cell can be configured as a cell for PUCCH transmission. At least one PUCCH cell group is configured in the UE based on the at least one cell configured for PUCCH transmission, and each PUCCH cell group includes one or more cells. A PUCCH cell group is also simply referred to as a PUCCH group. PUCCH transmission is configured not only for the primary cell but also for SCells, and the primary cell belongs to the primary PUCCH group, and the PUCCH-SCell configured for PUCCH transmission belongs to a secondary PUCCH group. The PUCCH on the primary cell is used for cells belonging to the primary PUCCH group, and the PUCCH on the PUCCH-SCell is used for cells belonging to the secondary PUCCH group.

[0067] The 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 cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) waveform or a discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) waveform. When the PUSCH is transmitted based on the DFT-s-OFDM waveform, the terminal applies transform precoding to transmit the PUSCH. For example, if transform precoding is not possible (e.g., transform precoding is disabled), the terminal transmits the PUSCH based on the CP-OFDM waveform, and if transform precoding is possible (e.g., transform precoding is enabled), the terminal transmits the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmissions are dynamically scheduled by UL grants in the 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 codebook-based or non-codebook-based.

[0068] 5 is a diagram illustrating an ACK / NACK transmission process. Referring to FIG. 5, a UE can detect a PDCCH in slot #n. Here, the PDCCH includes downlink scheduling information (e.g., DCI format 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 include the following information:

[0069] - Frequency domain resource assignment: Indicates the RB set assigned to the PDSCH.

[0070] Time domain resource assignment: Indicates K0 (e.g., slot offset), 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).

[0071] - PDSCH-to-HARQ_feedback timing indicator: Indicates K1.

[0072] - HARQ process number (4 bits): Indicates the HARQ process ID (Identity) for data (e.g., PDSCH, TB).

[0073] - PUCCH resource indicator (PRI): Indicates the PUCCH resource used for UCI transmission from among multiple PUCCH resources in a PUCCH resource set.

[0074] Thereafter, the UE receives the PDSCH from slot #(n+K0) according to the scheduling information of slot #n, and then transmits UCI via the PUCCH in slot #(n1+K1) after finishing receiving the PDSCH in slot #n1 (where n+K0≦n1). Here, the UCI includes a HARQ-ACK response to the PDSCH. For convenience, in FIG. 5, it is assumed that the SCS for the PDSCH and the SCS for the PUCCH are the same and that slot #n1 = slot #n+K0, but the present invention is not limited to this. If the SCSs are different, K1 is indicated / interpreted based on the SCS of the PUCCH.

[0075] If the PDSCH is configured to transmit a maximum of one TB, the HARQ-ACK response consists of 1 bit. If the PDSCH is configured to transmit a maximum of two TBs, the HARQ-ACK response consists of 2 bits if spatial bundling is not configured, and 1 bit if spatial bundling is configured. If the transmission time of the HARQ-ACK for multiple PDSCHs is specified as slot #(n+K1), the UCI transmitted in slot #(n+K1) includes the HARQ-ACK responses for multiple PDSCHs.

[0076] Whether a UE should perform spatial bundling for HARQ-ACK responses can be configured for each cell group (e.g., RRC / higher layer signaling). For example, spatial bundling is configured individually for each HARQ-ACK response transmitted via a PUCCH and / or a HARQ-ACK response transmitted via a PUSCH.

[0077] Spatial bundling is supported when the maximum number of TBs (or codewords) that can be received at one time (or scheduled by 1 DCI) in the serving cell is two (or more than two) (e.g., when the upper layer parameter maxNrofCodeWordsScheduledByDCI is equal to 2-TB). On the other hand, for 2-TB transmission, more than four layers are used, and for 1-TB transmission, up to four layers are used. As a result, when spatial bundling is configured for the cell group, spatial bundling is performed on serving cells in the cell group that can schedule more than four layers. A UE that wishes to transmit a HARQ-ACK response via spatial bundling in the serving cell can generate a HARQ-ACK response by performing a bit-wise logical AND operation on A / N bits for multiple TBs.

[0078] For example, assuming that a terminal receives DCI scheduling 2-TB and receives 2-TB via PDSCH based on the DCI, a 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. As a result, if both the first TB and the second TB are ACK, the terminal reports an ACK bit value to the base station, and if any one of the TBs is NACK, the terminal reports a NACK bit value to the base station.

[0079] For example, if only 1-TB is actually scheduled on a serving cell that is configured to receive 2-TB, the terminal can logically AND the A / N bit for that 1-TB with a bit value of 1 to generate a single A / N bit. As a result, the terminal reports the A / N bit for 1-TB to the base station as is.

[0080] A base station / UE has multiple parallel DL HARQ processes for DL ​​transmission. Multiple parallel HARQ processes enable continuous DL transmission while waiting for HARQ feedback for successful or unsuccessful reception of previous DL transmission. Each HARQ process is associated with a HARQ buffer in the Medium Access Control (MAC) layer. Each DL HARQ process manages state variables related to the number of transmissions of MAC Physical Data Blocks (PDUs) in the buffer, HARQ feedback for MAC PDUs in the buffer, the current redundancy version, etc. Each HARQ process is distinguished by a HARQ process ID.

[0081] 6 illustrates a PUSCH transmission process. Referring to FIG. 6, a UE 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 include the following information:

[0082] - Frequency domain resource assignment: Indicates the RB set assigned to the PUSCH.

[0083] - Time domain resource assignment: Indicates the slot offset K2, 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 are indicated by the SLIV (Start and Length Indicator Value) or are indicated separately.

[0084] Thereafter, the UE can transmit a PUSCH in slot #(n+K2) according to the scheduling information of slot #n, where the PUSCH includes the UL-SCH TB.

[0085] CSI-related operations

[0086] FIG. 7 shows an example of a procedure related to CSI.

[0087] The terminal receives CSI-related configuration information from the base station via RRC signaling 710. The CSI-related configuration information includes at least one of information on a CSI-IM (interference management) resource, information on a CSI measurement configuration, information on a CSI resource configuration, information on a CSI-RS resource, or information on a CSI report configuration.

[0088] - CSI-IM resources are configured for interference measurement (IM) of the terminal. In the time domain, the CSI-IM resource set is configured as periodic, semi-persistent, or aperiodic. The CSI-IM resources are configured as ZP (Zero Power)-CSI-RS for the terminal. ZP-CSI-RS is configured separately from NZP (Non-Zero Power)-CSI-RS.

[0089] - The UE can assume that the CSI-RS resources for channel measurement and the CSI-IM resources / NZP-CSI-RS resources for interference measurement (when the NZP-CSI-RS resources are used for interference measurement) configured for one CSI report have a QCL relationship for each resource with respect to 'QCL-Type D'.

[0090] The CSI resource configuration includes 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, where a CMR (channel measurement resource) is an NZP-CSI-RS for CSI acquisition, and an IMR (Interference measurement resource) is an NZP-CSI-RS for CSI-IM and IM.

[0091] CSI-RS may be configured for one or more terminals. A different CSI-RS configuration may be provided for each terminal, or the same CSI-RS configuration may be provided for multiple terminals. CSI-RS can support up to 32 antenna ports. CSI-RS corresponding to N (N is 1 or greater) antenna ports are mapped to N RE positions within a time-frequency unit corresponding to one slot and one RB. If N is 2 or greater, the N-port CSI-RS are multiplexed using CDM, FDM, and / or TDM. CSI-RS is mapped to REs other than the REs to which the CORESET, DM-RS, and SSB are mapped. In the frequency domain, CSI-RS is configured for the entire bandwidth, a partial bandwidth portion (BWP), or a portion of the bandwidth. CSI-RS is transmitted in every RB within the bandwidth where CSI-RS is configured (i.e., density = 1) or in every second RB (e.g., even- or odd-numbered RBs) (i.e., density = 1 / 2). When the CSI-RS is used as a Tracking Reference Signal (TRS), a single-port CSI-RS may be mapped onto three subcarriers in each resource block (i.e., density = 3). One or more CSI-RS resource sets are configured for a terminal in the time domain. Each CSI-RS resource set includes one or more CSI-RS configurations. Each CSI-RS resource set may be configured periodically, semi-persistently, or aperiodically.

[0092] The CSI reporting configuration includes configurations for feedback type, measurement resource, report type, etc. The NZP-CSI-RS resource set is used for the CSI reporting configuration of the terminal. The NZP-CSI-RS resource set may be associated with CSI-RS or SSB. In addition, multiple periodic NZP-CSI-RS resource sets are configured as TRS resource sets. (i) The feedback type includes 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), an L1-RSRP, etc. (ii) The measurement resource includes configurations for downlink signals and / or downlink resources on which the terminal should perform measurements to determine feedback information. The measurement resource is configured as a ZP and / or NZP-CSI-RS resource set associated with the CSI reporting configuration. The NZP-CSI-RS resource set includes a CSI-RS set or an SSB set. For example, L1-RSRP is measured for a CSI-RS set or an SSB set. (iii) Report type includes settings for the time when the UE reports and the uplink channel. The reporting time is set to periodic, semi-persistent, or aperiodic. Periodic CSI reporting is transmitted on the PUCCH. Semi-persistent CSI reporting is transmitted on the PUCCH or PUSCH based on the MAC CE indicating activation / deactivation. Aperiodic CSI reporting is indicated by DCI signaling. For example, the CSI request field of the uplink grant indicates one of various report trigger sizes. Aperiodic CSI reporting is transmitted on the PUSCH.

[0093] The terminal measures the CSI based on the configuration information related to the CSI. The CSI measurement includes receiving a CSI-RS (720) and calculating the received CSI-RS to obtain the CSI (730).

[0094] The terminal transmits a CSI report to the base station (740). The time and frequency resources available to the UE for the CSI report are controlled by the base station. The channel state information (CSI) includes at least one of a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), a SS / PBCH block resource indicator ( ...

[0095] The time domain behavior of CSI reporting supports periodic, semi-persistent, and aperiodic reporting. i) P (periodic)-CSI reporting is performed on short PUCCH or long PUCCH. The periodicity and slot offset of P-CSI reporting are 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. For SP-CSI on short PUCCH / long PUCCH, the periodicity and slot offset are configured by RRC, and CSI reporting is activated / deactivated by a separate MAC CE / DCI. For SP-CSI on the PUSCH, the periodicity of SP-CSI reporting is configured by RRC, but the slot offset is not. The activation / deactivation of SP-CSI reporting is determined by DCI (format 0_1). A separate RNTI (SP-CSI C-RNTI) is used for SP-CSI reporting on the PUSCH. The timing of the first CSI report follows the PUSCH time domain allocation value indicated by the DCI, and the timing of subsequent CSI reports follows the periodicity configured by RRC. DCI format 0_1 ​​includes a CSI request field, which activates / deactivates a pre-configured SP-CSI trigger state. The activation / deactivation of SP-CSI reporting is the same as or similar to the mechanism for data transmission on the SPS PUSCH. iii) AP-CSI reporting is performed on the PUSCH and is triggered by DCI. In this case, information related to triggering AP-CSI reporting is conveyed / indicated / configured by the MAC-CE.For AP-CSI with AP-CSI-RS, the AP-CSI-RS reception timing is set by RRC, and the transmission timing for AP-CSI reporting is dynamically controlled by DCI.

[0096] QCL (quasi-co location)

[0097] Two antenna ports are quasi-colocated if the channel properties of one antenna port can be inferred from the channel of the other antenna port. The channel properties include one or more of the following: delay spread, Doppler spread, frequency / Doppler shift, average received power, received timing / average delay, and spatial RX parameters.

[0098] A list of multiple TCI-State configurations is configured in the terminal by the higher layer parameter PDSCH-Config. Each TCI-State is associated with QCL configuration parameters between one or two DL reference signals and the DM-RS port of the PDSCH. The QCL includes qcl-Type1 for the first DL RS and qcl-Type2 for the second DL RS. The QCL type corresponds to one of the following:

[0099] - 'QCL-TypeA':{Doppler shift, Doppler spread, average delay, delay spread}

[0100] - 'QCL-TypeB':{Doppler shift, Doppler spread}

[0101] -'QCL-TypeC':{Doppler shift, average delay}

[0102] -'QCL-TypeD':{Spatial Rx parameter}

[0103] Beam Management (BM)

[0104] The BM process is a process for obtaining and maintaining a set of BS (or transmission and reception point (TRP)) and / or UE beams that can be used for downlink (DL) and uplink (UL) transmission / reception, and includes the following processes and terms:

[0105] - Beam measurement: An operation in which a BS or UE measures the characteristics of a received beamforming signal.

[0106] - Beam determination: The operation by which a BS or a UE selects its own transmit beam (Tx beam) / receive beam (Rx beam).

[0107] Beam sweeping: The operation of covering a spatial domain using transmit and / or receive beams in a predetermined manner for a certain time period.

[0108] - Beam report: An operation in which the UE reports information about beamformed signals based on beam measurements.

[0109] The BM process is divided into (1) a DL BM process using SSB or CSI-RS and (2) a UL BM process using SRS (Sounding Reference Signal). Each BM process includes Tx beam sweeping to determine the Tx beam and Rx beam sweeping to determine the Rx beam.

[0110] In this case, the DL BM process includes: (1) transmission of a beamformed DL RS (e.g., CSI-RS or SSB) by the BS; and (2) beam reporting by the UE.

[0111] Here, the beam report includes a preferred DL RS ID and its corresponding reference signal received power (RSRP). The DL RS ID is an SSB Resource Indicator (SSBRI) or a CSI-RS Resource Indicator (CRI).

[0112] M-TRP (multi-transmission and reception point) transmission

[0113] NR Standard Release 17 supports M-TRP PDCCH repeat transmission, M-TRP PDCCH / PDSCH SFN transmission, S-DCI-based M-TRP PUSCH repeat transmission, and single PUCCH resource-based M-TRP PUCCH repeat transmission.

[0114] These transmission techniques are all URLLC-targeted enhancements for increased reliability, and the same content (i.e., DCI, UL TB, or UCI) is repeatedly transmitted. In the case of M-TRP PDCCH repeated transmission, it is repeatedly transmitted using TDM or FDM, the M-TRP PDCCH / PDSCH SFN is repeatedly transmitted at the same time / frequency / layer, S-DCI-based M-TRP PUSCH repeated transmission is TDM, and single PUCCH resource-based M-TRP PUCCH repeated transmission is TDM and transmitted.

[0115] - S-DCI-based M-TRP PDCCH repetition transmission

[0116] In NR Standard Release 17, for M-TRP PDCCH repeat transmission, multiple CORESETs with different TCI states (i.e., different QCL RSs) are configured in the UE, and multiple Search Space (SS) sets connected to each of the CORESETs are configured. The base station instructs / configures the UE that the SS set connected to one CORESET and the SS sets connected to other CORESETs are linked for repeat transmission, so that the UE knows that the PDCCH candidates of the SS set are repeatedly transmitted.

[0117] For example, two CORESETs, CORESET #0 and CORESET #1, are configured in a UE, and CORESET #0 and CORESET #1 are connected to SS sets #0 and #1, respectively, so that SS set #0 and SS set #1 are linked. The UE can determine that a PDCCH candidate in SS set #0 and a PDCCH candidate in SS set #1 repeatedly transmit the same DCI, and can determine that a specific PDCCH candidate in SS set #0 and a specific PDCCH candidate in SS set #1 are a pair configured to repeatedly transmit the same DCI according to a predetermined rule. These two PDCCH candidates are called linked PDCCH candidates, and if the UE correctly receives any one of the two PDCCH candidates, it can successfully decode that DCI. However, when receiving PDCCH candidates for SS set #0, the QCL RS (i.e., downlink beam) in the TCI state of CORESET #0 connected to SS set #0 is used, and when receiving PDCCH candidates for SS set #1, the QCL RS (i.e., downlink beam) in the TCI state of CORESET #1 connected to SS set #1 is used, so that the linked PDCCH candidates are received using different beams.

[0118] - M-TRP SFN PDCCH

[0119] As a special case of M-TRP PDCCH repeated transmission, multiple TRPs can repeatedly transmit the same DCI using the same time / frequency / DM-RS port, which is called SFN PDCCH transmission. However, for SFN PDCCH transmission, the base station configures multiple TCI states in one CORESET instead of configuring multiple CORESETs with different TCI states. When the UE receives PDCCH candidates through the SS set connected to that one CORESET, it performs channel estimation and attempts decoding of the PDCCH DM-RS using all of the multiple TCI states.

[0120] - M-TRP SFN PDSCH

[0121] During the M-TRP PDSCH repeated transmission, two TRPs repeatedly transmit the channel on different resources. However, as a special case, when two TRPs use the same resources, i.e., when the same channel is repeatedly transmitted using the same frequency, time, and layer (or DM-RS port), the reliability of the channel can also be improved. In this case, the repeatedly transmitted same channel is received together over the air without resource division, and is therefore recognized as a single channel by the receiving end. In the NR standard, two downlink TCI states for PDSCH DM-RS reception are configured for PDSCH SFN transmission.

[0122] - S-DCI based M-TRP PUSCH repeat transmission

[0123] The base station configures two SRS sets in the UE for S-DCI-based M-TRP PUSCH transmission, and each SRS set is used to indicate uplink transmission ports for TRP #1 and TRP #2 and uplink beam / QCL information. In addition, the base station may indicate SRS resources for each SRS set using two SRI fields in one DCI and indicate up to two power control (PC) parameter sets. For example, the first SRI field indicates the SRS resources and PC parameter set defined in set 0, and the second SRI field indicates the SRS resources and PC parameter set defined in set 1.

[0124] The first SRI field indicates to the UE the uplink transmission port, PC parameter set, and uplink beam / QCL information for TRP #1, and accordingly, the UE transmits a PUSCH in a TO corresponding to SRS set #0. Similarly, the second SRI field indicates to the UE the uplink transmission port, PC parameter set, and uplink beam / QCL information for TRP #2, and accordingly, the UE transmits a PUSCH in a TO corresponding to SRS set #1.

[0125] - M-TRP PUCCH repetition transmission based on a single PUCCH resource

[0126] For single-PUCCH resource-based M-TRP PUCCH transmission, the base station activates / configures two pieces of spatial relation information for a single PUCCH resource in the UE, and when the UE transmits UL UCI via that PUCCH resource, each piece of spatial relation information is used to indicate spatial relation information for TRP #1 and TRP #2.

[0127] For example, the value indicated in the first spatial relation information indicates the transmit beam / PC parameters for TRP #1 to the UE, and this information is used to transmit the PUCCH in the TO corresponding to TRP #1. Similarly, the value indicated in the second spatial relation information indicates the transmit beam / PC parameters for TRP #2 to the UE, and this information is used to transmit the PUCCH in the TO corresponding to TRP #2.

[0128] In the Rel 17 standardization meeting, the configuration method was enhanced so that two pieces of spatial relation information are configured in the PUCCH resource for M-TRP PUCCH repeated transmission. That is, if a PC parameter is configured for each piece of spatial relation information, a spatial relation RS can be configured. As a result, PC information and spatial relation RS information corresponding to two TRPs can be configured using two pieces of spatial relation information, and the UE transmits on the PUCCH using the first piece of spatial relation information in TO 1, and transmits on the PUCCH with the same UCI (i.e., CSI, ACKNAK, SR) using the second piece of spatial relation information in TO 2.

[0129] Hereinafter, a PUCCH resource in which two pieces of spatial relation information are set is referred to as an M-TRP PUCCH resource, and a PUCCH resource in which one piece of spatial relation information is set is referred to as an S-TRP PUCCH resource.

[0130] TCI status / beam indication meaning

[0131] When receiving data / DCI / UCI for any frequency / time / space resource, using or mapping a specific TCI state (or TCI) means, in the case of downlink, estimating a channel from DM-RS using the QCL type and QCL RS indicated by that downlink TCI state in that frequency / time / space resource, and receiving / demodulating the data / DCI using the estimated channel.

[0132] In the uplink case, this means transmitting / modulating the DM-RS and data / UCI using the transmit beam and / or transmit power indicated by the uplink TCI state in that frequency / time / space resource.

[0133] The uplink TCI state includes the transmission beam or transmission power information of the UE, and instead of the TCI state, other parameters such as spatial relation info may be configured for the UE.

[0134] The uplink TCI status may be directly indicated in the DCI carrying the uplink grant, or may refer to spatial relationship information of SRS resources indicated by the SRI field of the UL grant DCI, or may refer to an open-loop transmit power control parameter linked to the value indicated by the SRI field of the UL grant DCI, or may indicate the uplink TCI using the DL grant DCI.

[0135] AI / ML(Artificial intelligence / machine learning)

[0136] Advances in AI / ML technology are leading to more intelligent and sophisticated nodes and terminals that make up wireless communication networks. In particular, the intelligence of networks / base stations is expected to enable the rapid optimization, derivation, and application of various network / base station decision parameter values ​​(e.g., transmit / receive power of each base station, transmit power of each terminal, precoder / beam of base station / terminal, time / frequency resource allocation for each terminal, multiplexing (duplexing) method of each base station, etc.) according to various environmental parameters (e.g., base station distribution / location, distribution / location / material of buildings / furniture, etc., terminal location / movement direction / speed, weather information, etc.). In response to this trend, many standardization groups (e.g., 3GPP, O-RAN) are considering introducing this technology, and research into it is also actively underway.

[0137] In the narrow sense, AI / ML can easily be called deep learning-based artificial intelligence, but conceptually it is as shown in Figure 8.

[0138] - Artificial Intelligence: This refers to all automation that allows machines to do the work that humans should do.

[0139] - Machine Learning: Without explicitly programming rules, machines learn patterns for decision-making from data.

[0140] - Deep Learning: An AI / ML model based on artificial neural networks, where the machine performs feature extraction and judgment from unstructured data in one go. The algorithm relies on a multi-layer network composed of interconnected nodes for feature extraction and transformation, inspired by the biological nervous system, i.e., neural networks. Common deep learning network architectures include deep neural networks (DNNs), recurrent neural networks (RNNs), and convolutional neural networks (CNNs).

[0141] Classification of AI / ML types based on various criteria

[0142] 1. Offline vs. Online

[0143] (1) Offline Learning: The process of database collection, learning, and prediction is carried out in sequence, i.e., collection and learning are carried out offline, and the completed program is installed in the field and used for prediction work. In most situations, this offline learning method is used.

[0144] (2) Online Learning: Recently, online learning has been developed, which takes advantage of the continuous generation of data that can be used for learning via the Internet, and uses the newly generated data to incrementally learn additional data and gradually improve performance.

[0145] 2. Classification by AI / ML framework concept

[0146] (1) Centralized Learning: The training data collected by multiple different nodes is reported to a centralized node, and all data resources, storage, learning (e.g., supervised, unsupervised, reinforcement learning), etc. are handled on one centralized node.

[0147] (2) Federated Learning: A collective AI / ML model is constructed based on data distributed among distributed data owners. Instead of bringing data to the AI / ML model, the AI / ML model is brought to the data source, allowing local nodes / individual devices to collect data and train their own AI / ML model copies, eliminating the need to report source data to a central node. In federated learning, the parameters / weights of the AI / ML model are simply retransmitted to a centralized node to support training of the general AI / ML model. The advantages of federated learning are increased computational speed and superior information security. In other words, since there is no need to upload personal data to a central server, it is possible to prevent the leakage and misuse of personal information.

[0148] (3) Distributed Learning: This refers to the concept of machine learning processes being scaled and distributed across a cluster of nodes. Training AI / ML models is split and shared across multiple nodes working simultaneously to speed up AI / ML model training.

[0149] 3. Classification by learning method

[0150] (1) Supervised Learning: Supervised learning is a machine learning task that aims to learn a mapping function from input to output when a dataset with specified labels is given. The input data is called training data and has a known label or outcome. Examples of supervised learning include: (i) Regression: Linear Regression, Logistic Regression; (ii) Instance-based Algorithms: k-Nearest Neighbor (KNN); (iii) Decision Tree Algorithms: CART; (iv) Support Vector Machines: SVM; (v) Bayesian Algorithms: Naive Bayes; and (vi) Ensemble Algorithms: Extreme Gradient Boosting, Bagging: Random Forest. Supervised learning can be further grouped by regression and classification problems, where classification is predicting labels and regression is predicting quantities.

[0151] (2) Unsupervised Learning: This is a machine learning task that aims to learn functions that explain hidden structures in unlabeled data. The input data has no labels and there is no known outcome. Some examples of unsupervised learning include K-means clustering, principal component analysis (PCA), nonlinear independent component analysis (ICA), and LSTM.

[0152] (3) Reinforcement Learning: In reinforcement learning (RL), agents interact with the environment through a trial-and-error process to optimize long-term goals. This is goal-oriented learning based on interactions with the environment. Examples of RL algorithms include (i) Q-learning, (ii) multi-armed bandit learning, (iii) deep Q network, state-action-reward-state-action (SARSA), (iv) temporal difference learning, (v) actor-critic reinforcement learning, (vi) deep deterministic policy gradient, and (vii) Monte-Carlo tree search. Reinforcement learning can be further grouped into AI / ML model-based reinforcement learning and AI / ML model-free reinforcement learning. Model-based reinforcement learning is an RL algorithm that uses predictive AI / ML models to determine switching probability between states using various dynamic states of the environment and AI / ML models that lead to compensation. Model-free reinforcement learning is an RL algorithm based on values ​​or policies that maximize future compensation. In a multi-agent environment / state, it requires low computational complexity and an accurate representation of the environment. On the other hand, RL algorithms may also be classified as value-based RL vs. policy-based RL, policy-based RL vs. non-policy RL, etc.

[0153] AI / ML models

[0154] 9 illustrates an example of an FFNN (Feed-Forward Neural Network) AI / ML model. Referring to FIG. 9, the FFNN AI / ML model includes an input layer, a hidden layer, and an output layer.

[0155] Figure 10 illustrates an example of an RNN (Recurrent Neural Network) AI / ML model. Referring to Figure 10, the RNN AI / ML model is a type of artificial neural network in which hidden nodes are connected by directional edges to form a cyclic structure (directed cycle), and is an AI / ML model suitable for processing sequential data such as voice and text. One type of RNN is Long Short-Term Memory (LSTM), which has a structure in which a cell state is added to the hidden state of an RNN. Specifically, in LSTM, an input gate, a forget gate, and an output gate are added to the RNN cell, and a cell state is added.

[0156] Figure 11 illustrates a convolution neural network (CNN) AI / ML model. CNN applies convolution, a technique commonly used in video and image processing, to achieve two goals: reducing the complexity of AI / ML models and extracting high-quality features. Referring to Figure 11, a kernel or filter refers to a unit or structure that applies a weight to a given range or unit of input. A stride refers to the range of movement of the kernel within the input. A feature map refers to the result of applying a kernel to the input. Padding refers to a padding value used to adjust the size of a feature map. Pooling refers to an operation (e.g., max pooling or average pooling) that downsamples a feature map to reduce its size.

[0157] Figure 12 shows an auto-encoder AI / ML model. Referring to Figure 12, an auto-encoder is a neural network that receives a feature vector x and outputs an identical or similar vector x', where the input node and the output node have the same features, and is a type of unsupervised learning.

[0158] FIG. 13 is a diagram illustrating a framework for 3GPP radio access network (RAN) intelligence.

[0159] Terms related to AI / ML are defined as follows (see 3GPP TS37.817):

[0160] - Data collection: Data collected from network nodes, management entities, or terminals, which is the basis for ML AI / ML model learning, data analysis, and inference.

[0161] - ML Model: A data-driven algorithm that applies ML methods to generate a set of outputs consisting of predicted information based on a set of inputs.

[0162] - ML training: An online or offline process of learning the features and patterns that best describe the data, training an ML AI / ML model, and obtaining a trained ML AI / ML model for inference.

[0163] - ML inference: The process of using a trained ML AI / ML model to guide predictions or decisions based on collected data and the ML AI / ML model.

[0164] Referring to Figure 13, data collection is a function that provides input data to the AI / ML model training and AI / ML model inference functions. Data preparation for each AI / ML algorithm (e.g., data preprocessing and reduction, formatting, and conversion) is not performed in the data collection function.

[0165] Examples of input data include measurements from UEs or other network entities, actor feedback, and AI / ML model output. Training data is data required as input to the AI / ML model training function. Inference data is data required as input to the AI / ML model inference function.

[0166] AI / ML model training is a function that is part of the AI / ML model testing procedure and performs ML AI / ML model training, validation, and testing that can generate AI / ML model performance metrics. If necessary, the AI / ML model training function can also be responsible for data preparation (e.g., data preprocessing and cleansing, formatting, and transformation) based on the training data provided by the data collection function.

[0167] AI / ML model deployment / update: Used to initially distribute a trained, validated, and tested AI / ML model to the AI / ML model inference function, or to propagate an updated AI / ML model to the AI / ML model inference function.

[0168] Model inference is a function that provides AI / ML model inference output (e.g., predictions or decisions). In some cases, the AI / ML model inference function may provide AI / ML model performance feedback to the AI / ML model training function. Optionally, the AI / ML model inference function may also perform data preparation (e.g., data preprocessing and cleansing, formatting, and transformation) based on the inference data communicated by the data collection function. Output refers to the AI / ML model inference output generated by the AI / ML model inference function. AI / ML model performance feedback is used to monitor the performance of the AI / ML model.

[0169] An actor is a function that receives the output of an AI / ML model inference function and triggers or executes that action. An actor triggers work towards other entities or itself. Feedback is training or inference data or information needed to derive performance feedback.

[0170] data set

[0171] The data used in AI / ML includes at least one of AI / ML model training data, validation data, and test data.

[0172] AI / ML model training data is a dataset for training an AI / ML model.

[0173] Validation data is a dataset used to validate an AI / ML model that has already completed training. It is used to prevent overfitting of the AI / ML model training dataset. It can also be a dataset used to select the best AI / ML model from various AI / ML models trained during the training process, and is therefore considered a type of training.

[0174] Test data is a data set for final evaluation and may not be related to learning.

[0175] For example, the AI / ML model training data and validation data may be used in a ratio of 8:2 or 7:3, or if test data is also taken into account, a ratio of 6:2:2 (training:validation:test) may be used.

[0176] Collaboration level

[0177] As an example, depending on whether AI / ML functions are available between the base station and the terminal, the cooperation level (or category) is defined as follows, and variations by combining or separating the following levels are also possible.

[0178] Cat 0a) No collaboration framework: AI / ML algorithms are implemented but do not require changes to the wireless interface.

[0179] Cat 0b) A modified interface is provided to implement a more efficient AL / ML algorithm.

[0180] Cat 1) Cooperation between nodes is possible to improve each node's AI / ML algorithm. The terminal receives or assists the base station for training, adaptation, etc. However, the exchange of AI / ML model information between network nodes is not required.

[0181] Cat 2) Joint AI / ML operation between a terminal and a base station, which requires instruction / exchange between network nodes.

[0182] TD (Time Domain) Compressed Codebook

[0183] 14 and 15 are diagrams showing an example of reporting PMI for multiple time instances.

[0184] In particular, the PMI shown in Figs. ref_rsc , PMI ref_rsc+τ and PMI ref_rsc+2τ is compressed based on a Time Domain (TD) compression codebook to reduce the PMI feedback overhead.

[0185] 14 and 15, in order to determine the time instance of the channel represented by the PMI, the base station performs the following signaling to the UE. As an example of the signaling, the signaling is indicated by a parameter of RRC signaling for codebook configuration.

[0186] First, the number of time instances to be represented by the PMI is specified. In Figures 14 and 15, the number of time instances is three. The number of time instances is set in consideration of the time variation of the channel. For this purpose, the UE transmits its own speed information, Doppler information( Doppler shift / spread) etc. Or, the UE reports its speed or Doppler The UE reports the number of time instances it prefers from the information to the base station, which then confirms or makes the final selection. The UE reports candidate values ​​for the number of time instances as UE capability.

[0187] 14 and 15, the interval τ between each time instance is indicated. The τ value is set taking into consideration the time variation of the channel. For this purpose, the UE transmits its own speed information, Doppler information( Doppler shift / spread) etc. Or, the UE reports its speed or Doppler The UE reports its preferred τ value from the information to the base station, which confirms or selects it. The τ value may be expressed as absolute time, slot, OFDM symbol, etc. The UE reports candidate values ​​for the τ value as UE capabilities.

[0188] This indicates which time instance the CSI reference resource corresponds to among the time instances set as described above.

[0189] In FIG. 14, among the three time instances, the CSI reference resource is set for the first time instance, and for this reason, the base station sets the time instance offset of the CSI reference resource to 0. As the CSI reference resource is set for the first time instance, the remaining time instances at subsequent time points are set after the CSI reference resource. In FIG. 15, among the three time instances, the CSI reference resource is set for the last (third) time instance, and for this reason, the base station sets the time instance offset of the CSI reference resource to 2. As the CSI reference resource is set for the third time instance, the remaining time instances at the previous time points are set before the CSI reference resource.

[0190] The time instance offset is set in consideration of the time-varying nature of the channel. For this reason, the UE reports its speed information, Doppler information ( Doppler shift / spread), etc. to the base station. Alternatively, the UE reports to the base station the time instance offset selected from its speed or Doppler information, and the base station confirms or makes the final selection of this. Also, depending on the UE implementation, as shown in FIG. 14, the UE that can set the time instance offset to other time instances than the last time instance, and as shown in FIG. 15, the UE that can set the time instance offset only to the last time instance are classified, and this is reported as UE capability. The latter does not need to perform channel prediction, so the implementation is simple, but the former needs to perform channel prediction, so the implementation is complex.

[0191] More specifically, in the case of the former, the minimum value of the setable time instance offset, or candidates for the setable time instance offset values can be additionally reported. The smaller the minimum value, the more channel prediction needs to be performed, so the UE implementation becomes complex.

[0192] <CSI Overhead Reduction Method>

[0193] In the method of reporting PMI for multiple time instances described above in Figures 14 and 15, if the uplink resource (e.g., PUCCH resource / PUSCH resource) for reporting CSI is configured to be smaller than the CSI payload, it is necessary to reduce the PMI feedback overhead.

[0194] 1. The first method to reduce feedback overhead is to report PMI at multiple time instances with different accuracies.

[0195] (1) First, when reporting one W1 commonly applied to multiple time instances and multiple W2s corresponding to each of the multiple time instances without TD (Time Domain) compression, the following methods a) to c) can be considered.

[0196] (1)-(a) Omission of W2 reporting for specific time instances, such as odd-numbered time instances (or even-numbered time instances), the most recent time instances (e.g., the most recent N / 2 time instances out of N time instances), or other time instances.

[0197] Alternatively, a specific time instance refers to a time instance until a CSI payload is transmitted on an uplink resource when W2 is omitted in reverse chronological order starting from the most recent time instance L (i.e., L-1, L-2, ...). Conversely, a specific time instance refers to a time instance until a CSI payload is transmitted on an uplink resource when W2 is omitted in chronological order starting from the first time instance (i.e., the second time instance, the third time instance, ...).

[0198] Nevertheless, if there are insufficient uplink resources, only W2 for a specific time instance (eg, W2 calculated by a conventional method based on a conventional CSI reference resource) is reported.

[0199] (1)-(b) Instead of omitting the W2 report for a particular time instance, the parameters of W2 for the particular time instance can be adjusted to reduce the size of the payload.

[0200] For example, the granularity of the amplitude of the non-zero coefficient (NZC) can be reduced (i.e., the number of bits for indicating the amplitude can be reduced), the granularity of the phase of the NZC can be reduced (e.g., reducing the number of bits by reducing from 16PSK to 8PSK), the number of NZCs can be reduced, or the upper limit (K0) of the number of NZCs can be reduced. Also, the payload of W2 can be reduced by omitting some NZCs from the CSI report (e.g., omitting NZCs with small amplitude values ​​from the CSI report) or by reducing the number of frequency domain (FD) basis vectors (M).

[0201] Alternatively, the number of layers can be reduced for a specific time instance, and the payload of W2 can be reduced and reported. For example, when RI=2 is determined and PMI is reported for t1, t2, and t3, W2 for RI=2 should be reported at each time instance, but the payload can be reduced by omitting W2 reporting for a specific layer at a specific time instance.

[0202] When W2 for t1, t2, and t3 are denoted as W2(t1), W2(t2), and W2(t3), respectively, if RI is 2, PMI for W2(t1), W2(t2), and W2(t3) must basically be calculated / reported for layer 2, layer 2, and layer 2, respectively. As shown in 2-2-2, if uplink resources are insufficient, CSI omission can be performed in the order of 2-2-1 -> 2-1-1 -> 1-1-1 -> 1-1-0 -> 1-0-0 -> 0-0-0. Alternatively, CSI omission can be performed in the order of 2-2-2 -> 2-2-1 -> 2-2-0 -> 2-1-0 -> 2-0-0 -> 1-0-0 -> 0-0-0.

[0203] (1)-(c) Meanwhile, as a combination of the above (1)-(a) and (1)-(b), if uplink resources are still insufficient after applying (1)-(b), W2 reporting can be omitted by applying (1)-(a). Alternatively, if uplink resources are still insufficient after applying (1)-(a), W2 payload can be reduced and reported by applying (1)-(b) to the remaining W2s that are not omitted.

[0204] (2) Next, when a TD compression codebook is used, PMI for multiple time instances is represented by a single codebook. That is, the PMI for multiple time instances is represented at once by a linear combination of TD basis vectors. For example, since the number of time instances is the same as the number of TD basis vectors, time instances 0 to 3 are represented by a linear combination of TD basis vectors with a length of 4. As a result, the i-th element of the linearly combined TD basis vector represents the PMI for the i-th time instance. In this case, the above (1)-(a) to (1)-(c) can be extended and applied as follows.

[0205] (2)-(a) When (1)-(a) is extended and applied to the TD compression codebook, PMI reporting is omitted for a specific time instance, and as a result, the time instance is excluded from the TD basis vectors. For example, if TD basis vectors with a length of 4 are configured to be used for time instance 0 to time instance 3, if PMI for even-numbered time instances is omitted from the CSI reporting, TD basis vectors with a length of 2 must be used for time instance 1 and time instance 3.

[0206] The number of TD basis vectors, N, is proportional to the length of the TD basis vector (e.g., N is the length of the TD basis vector / 4), and as the length of the TD basis vector (i.e., the number of time instances) becomes smaller, N also becomes smaller. Also, as N becomes smaller, the PMI payload becomes smaller as follows:

[0207] Specifically, an NZC is selected for each layer in a 2L*M*N-bit bitmap. Here, 2L is the number of SD (Spartial domain) basis vectors, M is the number of FD (Frequency domain) basis vectors, and N is the number of TD (Time Domain) basis vectors. In this case, as N becomes smaller, the size of the bitmap per layer becomes smaller. In addition, the upper limit K0 of KNZ (i.e., the number of NZCs) per layer can be determined in proportion to 2L*M*N (e.g., K0 = 2L*M*N / 8). As N becomes smaller, K0 also becomes smaller, and KNZ decreases. Because amplitude and phase need to be reported for each NZC, a decrease in KNZ, which is the number of NZCs, reduces the PMI payload.

[0208] (2)-(b) When (1)-(b) are extended and applied to the TD compression codebook, the PMI parameters for a specific time instance can be adjusted to reduce the payload reported. For example, the payload of W2 can be reduced by reducing the granularity of the NZC amplitude (i.e., reducing the number of bits to indicate the amplitude), reducing the granularity of the NZC phase (e.g., from 16PSK to 8PSK), reducing the number of NZCs, reducing the upper limit K0 on the number of NZCs, omitting some NZCs from the CSI report (e.g., omitting NZCs with small amplitude values ​​from the CSI report), or reducing the number of FD (Frequency Domain) basis vectors (M).

[0209] Alternatively, the time instances of PMI to be reported can be set differently for each layer. For example, when RI is 4, the first layer reports PMI for all time instances (in this case, W2 may be reported for each time instance with or without applying a TD compression codebook), the second layer reports PMI for even-numbered time instances, the third layer reports PMI for even-numbered time instances among the time instances reported by the second layer (i.e., the third layer reports CSI for only half of the time instances of the second layer), and the fourth layer reports PMI for even-numbered time instances among the time instances of the third layer. Alternatively, the third and fourth layers also report PMI for the same time instances as the second layer.

[0210] Alternatively, the first layer reports PMI for all time instances, the second layer reports PMI for the time instances in the chronologically forward half, the third layer reports PMI for the time instances in the chronologically forward half, and the second layer reports PMI for the time instances in the chronologically forward half.

[0211] (2)-(c) Meanwhile, as a combination of the above (2)-(a) and (2)-(b), if uplink resources are still insufficient after applying (2)-(b), W2 reporting can be omitted by applying (2)-(a). Alternatively, if uplink resources are still insufficient after applying (2)-(a), W2 payload can be reduced and reported by applying (2)-(b) to the remaining W2s that are not omitted.

[0212] 2. The second method for reducing feedback overhead is to omit reporting NZC (non-zero coefficient) for a specific TD basis vector when using a TD compression codebook.

[0213] Specifically, we extend the process of omitting NZC in the conventional FD compression codebook to the TD compression codebook. First, we explain the process of omitting NZC in the conventional FD compression codebook, and then we will explain the proposed method later.

[0214] In a conventional CSI omission scheme, the NZC report for a specific FD basis vector using a Type II codebook can be omitted to reduce the payload size by the following Equation 1, which is disclosed in 3GPP 38.314 Section 5.2.3.

[0215] [Formula 1]

number

[0216] According to the above equation 1, the NZC of a specific FD beam, i.e., an FD beam far away from the FD beam with index 0 due to π(f), calculates a Pri(l,i,f) value that is larger than the NZCs of other FD beams, and the larger the Pri(l,i,f) value, the lower the priority, so the NZC of the specific FD beam is omitted first from the NZC report. The NZC for the same FD beam has a lower priority the larger the SD beam index, and the NZC for the same FD beam and the same SD beam has a lower priority the larger the layer index. Here, SD beam and FD beam refer to SD basis vectors and FD basis vectors.

[0217] We propose to modify the above Equation 1 so that the NZC priority is determined not only for the FD basis vector index (f), the SD basis vector index (i), and the layer index (l), but also for the TD basis vector index (t), i.e., the TD beam index, as follows: where υ is the number of layers, and 2L is the number of SD basis vectors.

[0218] 2-(1) First, the priority of NZC can be determined by the following formula 2.

[0219] [Formula 2]

number

[0220] where ν is the number of layers, 2L is the number of SD basis vectors, N3 is a value related to the number of FD basis vectors, and π'(t) is a function that determines the priority for the t-th TD basis vector, where t is 0, 1, 2, ..., N-1, and N is the number of TD basis vectors. More simply, π'(t) may be a function that maps t 1:1 with integer values ​​between 0, 1, 2, ..., N-1.

[0221] For example, in a 1:1 mapping of t with t, the forward TD basis vectors have higher priority than the backward TD basis vectors, and conversely, in a 1:1 mapping of t=0, 1, 2, ..., N-1 to N-1, N-2, N-3, ..., 0, the backward TD basis vectors have higher priority than the forward TD basis vectors. Alternatively, if t is even, it maps to a smaller value than if it is odd, and for even t values ​​and odd t, the forward TD basis vectors map to a smaller (or larger) value. In this case, the TD basis vectors with even indices have higher priority.

[0222] Alternatively, π'(t) may be a function that maps t 1:1 with integer values ​​between 0 and N4-1. That is, it can be expressed as π'(t) = t. N4 is the number of time instances and is equal to the length of the TD basis vectors, and N TD basis vectors can be generated by selecting N vectors in the DFT matrix of size (N4*N4).

[0223] To simplify this, the larger the Pri(l,i,f,t) value, the lower the priority, so the NZC for a specific TD beam is omitted earlier in the NZC report. The larger the FD beam index, the lower the priority for NZCs for the same TD beam, and the larger the SD beam index, the lower the priority for NZCs for the same TD beam and the same FD beam. The larger the layer index, the lower the priority for NZCs for the same TD beam, the same FD beam, and the same SD beam. Here, SD beam and FD beam refer to SD basis vectors and FD basis vectors.

[0224] Although π'(t) is assumed to be a single permutation scheme, the permutation scheme can be changed depending on the mobile terminal's moving speed, direction, etc. After multiple permutation schemes are preset, an indicator of which permutation scheme was used can be considered as a new feedback factor. Alternatively, permutation information can be notified using a combinatorial number, etc.

[0225] According to the priority of the NZC determined based on Equation 2, groups of NZC values ​​(i.e., amplitude and / or phase) are determined, and each group also includes a bitmap for the NZC belonging to the group (i.e., a bitmap for distinguishing NZC from ZC among 2L*M*N coefficients). For example, half of the NZCs corresponding to higher priorities are determined to be in group 1, and the other NZCs are determined to be in group 2. When NZCs are omitted for all TD basis vectors, PMI is reported using a conventional codebook for one time instance (e.g., conventional CSI reference resource slot) instead of the TD compressed codebook, and the CSI payload is determined by applying the conventional CSI omission rule to the conventional codebook.

[0226] 2-(2) Next, the priority of the NZC can be determined by the following formula 3.

[0227] [Formula 3]

number

[0228] π'(t) is the same as that defined in Equation 2. However, Equation 3 is obtained by changing the order of application of the priorities of the FD basis vectors and the TD basis vectors corresponding to f and t in Equation 2.

[0229] That is, in Equation 2, the priority of NZC is determined first by the TD basis vector, and then the priority is determined by the FD basis vector for the same TD basis vector. On the other hand, in Equation 3, the priority of NZC is determined first by the FD basis vector, and then the priority is determined by the TD basis vector for the same FD basis vector.

[0230] In Equation 3, π'(t) is assumed to be a function that outputs values ​​between 0 and N-1. However, if π'(t) is a function that outputs values ​​between 0 and N4-1, then N in Equation 3 must be changed to N4.

[0231] When NZC is omitted for all FD basis vectors, PMI is reported using the WB codebook instead of the FD compression codebook, and the CSI omission process can be applied to the WB codebook by setting π(f) in Equation 3 to 0. That is, WB PMI is reported for multiple time instances using the TD compression codebook, and if uplink resources are insufficient, NZCs of TD basis vectors with lower priority are omitted. When the NZCs of both the FD basis vectors and the TD basis vectors are omitted, PMI is reported using the conventional WB codebook for one time instance (e.g., conventional CSI reference resource slot).

[0232] 2-(3) If the conventional rule, Formula 1, is used as is, there is a possibility that multiple NZCs with the same priority exist because Formula 1 does not take into account TD basis vectors. Therefore, we propose a method to determine the priority among multiple NZCs with the same priority using the index of the TD basis vector.

[0233] For example, in Equation 1, assuming that there are three NZCs with the same π(f),f,i,l and the same priority, and each NZC is a coefficient for TD basis vector 1 to TD basis vector 3, the priority of the three NZCs is determined according to the priority of the TD basis vector determined using π' in 2-(1) above.

[0234] After prioritization has been done in this way, half of the NZCs with higher priorities can be configured in Group 1, and the other NZCs in Group 2, as in the past.

[0235] Furthermore, the NZCs of some TD basis vectors can be set to 0 (i.e., omitted) and proposal 2-(3) can be applied. That is, when uplink resources are insufficient, some TD basis vectors are selected from among the TD basis vectors corresponding to the NZCs, and the NZCs of those TD basis vectors are first omitted, and then proposal 2-(3) is applied. In this case, the selection of some TD basis vectors is determined as even-numbered TD basis vectors (or odd-numbered TD basis vectors), the front TD basis vectors (or rear TD basis vectors) obtained by halving the TD basis vectors, TD basis vectors with small coefficient amplitudes, etc.

[0236] 2-(4) Priority can be determined by applying both Equation 2 and Equation 3. For example, Equation 2 is applied first to omit half (or part) of the NZCs corresponding to low priorities. If there are still insufficient uplink resources, Equation 3 is applied to the remaining NZCs to omit half (or part) of the NZCs corresponding to low priorities. Through this process, NZCs are first omitted for some TD basis vectors with low priorities, and then NZCs are omitted for some FD basis vectors with low priorities. Of course, Equation 2 may be applied after first applying Equation 3 to omit some NZCs.

[0237] The BS can configure the UE based on which of the above Equations 1 to 3 the NZC omission is applied.

[0238] 3. As the third method for reducing feedback overhead, we propose a method to reduce the PMI feedback overhead by setting a small upper limit K0 on the number of NZCs when using a TD compression codebook.

[0239] In a conventional Type II codebook, the upper limit of the number of NZCs is set for each layer so that it does not exceed K0=2L*M*beta, where beta is a constant greater than 0 and less than or equal to 1.

[0240] In a TD compression codebook, 2L*M*N coefficients (NZC or ZC) are defined for each layer according to the number N of TD basis vectors. Reflecting this, if the upper limit K0 on the number of NZCs per layer is set to 2L*M*N*beta, overhead increases excessively as the value of N increases. To reduce this overhead increase, beta can be set to decrease as N increases. For example, when TD compression is not used, K0 = 2L*M*N*beta, N = 1, and the conventional beta value is applied. On the other hand, when TD compression is used, i.e., for N > 1, a value smaller than the conventional beta value is applied.

[0241] Alternatively, the beta value can be kept at the conventional value, but an alpha value can be added, which operates in a similar manner. For example, let's determine K0 = 2L * M * N * beta * alpha, but if TD compression is not used, set N = 1, apply the conventional beta value, and set alpha = 1. On the other hand, if TD compression is used, i.e., for N > 1, use the conventional beta value and apply an alpha value smaller than 1. Also, alpha can be set smaller as N increases.

[0242] In addition, in the current 3GPP NR standard, to prevent the number of NZCs from increasing excessively as the rank increases, the sum of the number of NZCs in all layers is limited to not exceed 2K0. When a TD compression codebook is used, this limit can be set more strictly. For example, the sum of the number of NZCs in all layers can be limited to not exceed m*K0 (e.g., m<2 and m=1).

[0243] When reporting one W1 commonly applied to multiple time instances and multiple W2s corresponding to each of the multiple time instances without TD (Time Domain) compression, a different beta value can be applied to each of the multiple time instances, thereby adjusting the feedback payload. Specifically, a larger beta value can be applied to one slot (e.g., a conventional CSI reference resource slot) among the multiple time instances, and smaller values ​​can be applied to the other time instances, thereby reducing the number of NZCs. Alternatively, a larger beta value can be applied to earlier time instances, or conversely, a larger beta value can be applied to more future time instances. Because CSI calculation for future time instances may be inaccurate, it is preferable to reduce the beta.

[0244] 4. According to the prior art, a base station can set a codebook subset restriction (CBSR) to prevent a UE from reporting a specific PMI. For example, the base station sets a restriction on SD beams that a UE can report for interference management purposes, and sets an amplitude (or power) restriction for a specific SD beam.

[0245] As a fourth method for reducing feedback overhead, when PMI for multiple time instances is reported, we propose setting a different CBSR for each time instance, because the base station performs different interference management for each time instance.

[0246] For example, the base station can be configured not to report SD beam 0 and SD beam 1 to the UE at t1 and not to report SD beam 1 and SD beam 2 to the UE at t2, so that downlink transmission is not performed using SD beam 0 and SD beam 1 at t1 and not to perform downlink transmission using SD beam 1 and SD beam 2 at t2. More specifically, the base station can configure a maximum allowed average amplitude at t1 and a maximum allowed average amplitude at t2. The maximum allowed average amplitude is replaced with a maximum allowed average power.

[0247] In addition to restricting each SD beam and / or power for each time instance, the TD basis vectors can also be restricted. Applying TD basis vector restrictions to all SD beams may seem excessive, so it is preferable to operate in conjunction with specific SD beams. For example, SB beam set 1 is restricted to not use TD basis vectors 0 through 3, and SB beam set 2 is restricted to not use TD basis vectors 4 through 7.

[0248] FIG. 16 is a flowchart illustrating a method for reporting CSI for multiple time instances according to the present disclosure.

[0249] 16, in step A05, the UE receives a control signal for CSI reporting from the BS, where the control signal includes information on a channel measurement resource (CMR) and / or information on an uplink grant for reporting the CSI.

[0250] Next, in step A10, the UE receives at least one CMR from the BS based on the control signal, and in step A15, estimates at least one Precoding Matrix Index (PMI) for at least one time instance, i.e., a codeword, using a Time Domain Compressed (TD) codebook based on the at least one CMR. In other words, estimates multiple NZCs (non-zero coefficients) constituting the codeword. Note that the maximum number of NZCs per layer is determined based on the product of the number of TD basis vectors, the number of FD basis vectors, and the number of SD basis vectors.

[0251] On the other hand, if the uplink grant resource is smaller than the payload of the CSI consisting of the estimated NZC, the UE constructs the CSI by dropping the NZCs in descending order of priority value, as in step A20.

[0252] Specifically, the multiple NZCs have priority values ​​determined by considering the index of a TD (Time domain) basis vector, the index of a FD (Frequency domain) basis vector, the index of a SD (Spatial domain) basis vector, and the layer index in that order.

[0253] In this case, the multiple NZCs have a higher priority value the larger the index of the TD basis vector, and if the indices of the TD basis vectors are the same, the larger the index of the FD basis vector, the higher the priority value, and if the indices of the TD basis vectors and the FD basis vectors are the same, the larger the index of the SD basis vector, the higher the priority value, and if the indices of the TD basis vectors, the FD basis vectors and the SD basis vectors are the same, the larger the layer index, the higher the priority value.

[0254] More specifically, the priority value (Pri(l,i,f,t)) of the NZC where the layer index is l, the index of the SD basis vector is i, the index of the FD basis vector is f, and the index of the TD basis vector is t can be determined by the above equation 2.

[0255] Finally, in step A25, the UE transmits the CSI including information about NZC to the BS based on an uplink grant.

[0256] In the proposal, reporting CSI for multiple time instances may mean that one CMR configured for CSI calculation is configured to burst continuously for a short time interval (e.g., every slot or every symbol), that a TD compressed codebook is configured for PMI reporting, that one W1 and multiple W2s corresponding to other time instances are configured for PMI reporting, or that multiple time instances / multiple CSI reference resources are configured.

[0257] The proposal describes a scheme for reducing the payload using PMI as an example, but it can be extended to other CSI other than PMI, for example, CQI.

[0258] Combinations / combinations of the above suggestions may ultimately be applied.

[0259] Although the TD compression codebook is used as an example in the above proposal, the proposed method can be extended and applied to a DD (Doppler domain) compression codebook.

[0260] The proposal can be utilized as a method for reducing the size of the CSI payload in addition to CSI omission. CSI omission can be performed when the uplink resource (e.g., PUCCH resource / PUSCH resource) for reporting CSI is configured to be smaller than the CSI payload, but the proposed method can be applied to reduce the CSI payload regardless of the uplink resource.

[0261] The proposal can also be applied to a case where an AIML UE predicts future CSI (eg, CSI for a channel after the CSI reporting time) and reports it to a base station.

[0262] The parameters mentioned in the proposal, whether the proposal is applicable, etc. may be instructed by the base station to the UE, reported by the UE to the base station, or set to fixed values.

[0263] FIG. 17 illustrates a communication system 1 to which the present invention can be applied.

[0264] Referring to FIG. 17, the communication system 1 includes wireless devices, base stations, and a network. Here, the wireless devices refer to devices that communicate using wireless connection technologies (e.g., 5G NR, LTE), and are also referred to as communication / wireless / 5G devices. The wireless devices include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an XR (eXtended Reality) device 100c, a handheld device 100d, a home appliance 100e, an IoT (Internet of Things) device 100f, and an AI server / device 400. For example, the vehicles include vehicles equipped with wireless communication capabilities, autonomous vehicles, vehicles capable of vehicle-to-vehicle communication, and the like. Here, the vehicles include unmanned aerial vehicles (UAVs) (e.g., drones). XR devices include Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) devices, and are embodied in the form of Head-Mounted Devices (HMDs), Head-Up Displays (HUDs) mounted on vehicles, TVs, smartphones, computers, wearable devices, home appliances, digital billboards, vehicles, robots, etc. Mobile devices include smartphones, smart pads, wearable devices (e.g., smart watches, smart glasses), computers (e.g., laptops, etc.), etc. Home appliances include TVs, refrigerators, washing machines, etc. IoT devices include sensors, smart meters, etc. For example, base stations and networks may also be embodied as wireless devices, and a specific wireless device 200a may operate as a base station / network node for other wireless devices.

[0265] The wireless devices 100a to 100f are connected to a network 300 via a base station 200. The wireless devices 100a to 100f are equipped with AI (Artificial Intelligence) technology, and are connected to an AI server 400 via the network 300. The network 300 is configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices 100a to 100f can communicate with each other via the base station 200 / network 300, but can also communicate directly without going through the base station / network (e.g., sidelink communication). For example, vehicles 100b-1 and 100b-2 can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). IoT devices (e.g., sensors) can also communicate directly with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0266] Wireless communication / connections 150a, 150b, and 150c are performed between the wireless devices 100a to 100f and the base stations 200, and between the base stations 200. Here, the wireless communication / connections are performed using various wireless connection technologies such as uplink / downlink communication 150a and sidelink communication 150b (or D2D communication), and communication between base stations 150c (e.g., relay, Integrated Access Backhaul (IAB)) (e.g., 5G NR). Through the wireless communication / connections 150a, 150b, and 150c, the wireless devices and the base stations, and the base stations, can transmit / receive wireless signals to / from each other. For example, the wireless communication / connections 150a, 150b, and 150c can transmit / receive signals via various physical channels. To this end, according to various proposals of the present invention, any one of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes is performed.

[0267] FIG. 18 illustrates a wireless device to which the present invention can be applied.

[0268] 18, a first wireless device 100 and a second wireless device 200 transmit and receive wireless signals using various wireless access technologies (e.g., LTE, NR), where {first wireless device 100, second wireless device 200} corresponds to {wireless device 100x, base station 200} and / or {wireless device 100x, wireless device 100x} in FIG.

[0269] The first wireless device 100 includes one or more processors 102 and one or more memories 104, and further includes one or more transceivers 106 and / or one or more antennas 108. The processor 102 is configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. For example, the processor 102 processes information in the memory 104 to generate first information / signals and then transmits a wireless signal including the first information / signals via the transceiver 106. The processor 102 also receives a wireless signal including second information / signals via the transceiver 106 and then stores information obtained from signal processing of the second information / signals in the memory 104. The memory 104 is coupled to the processor 102 and stores various information related to the operation of the processor 102. For example, the memory 104 stores software code including instructions for performing some or all of the processes controlled by the processor 102 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. Here, the processor 102 and memory 104 are part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 106 is coupled to the processor 102 and transmits and / or receives wireless signals via one or more antennas 108. The transceiver 106 includes a transmitter and / or a receiver. The transceiver 106 may also be referred to as an RF (radio frequency) unit. In the present invention, a wireless device may also refer to a communication modem / circuit / chip.

[0270] The second wireless device 200 includes one or more processors 202 and one or more memories 204, and further includes one or more transceivers 206 and / or one or more antennas 208. The processor 202 is configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. For example, the processor 202 processes information in the memory 204 to generate third information / signal, and then transmits a wireless signal including the third information / signal via the transceiver 206. The processor 202 also receives a wireless signal including a fourth information / signal via the transceiver 206, and then stores information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 is coupled to the processor 202 and stores various information related to the operation of the processor 202. For example, the memory 204 stores software code including instructions for performing some or all of the processes controlled by the processor 202 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. Here, the processor 202 and memory 204 are part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 206 is coupled to the processor 202 and transmits and / or receives wireless signals via one or more antennas 208. The transceiver 206 includes a transmitter and / or a receiver. The transceiver 206 may also be referred to as an RF unit. In the present invention, a wireless device may also refer to a communication modem / circuit / chip.

[0271] The hardware elements of the wireless devices 100, 200 are described in more detail below. Without limitation, 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, and SDAP). The 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, suggestions, methods, and / or flowcharts disclosed herein. The one or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. The one or more processors 102, 202 generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed herein and provide them to the one or more transceivers 106, 206. The one or more processors 102, 202 receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and derive the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein.

[0272] The one or more processors 102, 202 may also be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. For example, the one or more processors 102, 202 may include 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). The descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein may be implemented using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein may be included in the one or more processors 102, 202 or may be stored in one or more memories 104, 204 and executed by the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods and / or flow charts disclosed in this specification may be embodied using firmware or software in the form of code, instructions and / or sets of instructions.

[0273] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various types of data, signals, messages, information, programs, code, instructions, and / or commands. The one or more memories 104, 204 may be comprised of 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 internal and / or external 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 techniques, such as wired or wireless connections.

[0274] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc., as referenced in the methods and / or flowcharts herein to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc., as referenced in the descriptions, functions, procedures, suggestions, methods and / or flowcharts herein from one or more other devices. For example, one or more transceivers 106, 206 can be coupled 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. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, one or more transceivers 106, 206 are coupled to one or more antennas 108, 208, and are configured to transmit and receive user data, control information, radio signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein via the one or more antennas 108, 208. In this specification, one or more antennas may refer to multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 convert the received user data, control information, radio signals / channels, etc., from RF band signals to baseband signals for processing by one or more processors 102, 202. The one or more transceivers 106, 206 convert the user data, control information, radio signals / channels, etc., processed by one or more processors 102, 202, from baseband signals to RF band signals. For this purpose, the one or more transceivers 106, 206 include (analog) oscillators and / or filters.

[0275] 19 shows another example of a wireless device to which the present invention is applied. The wireless device may be implemented in various forms depending on the use case / service (see FIG. 17).

[0276] 19, wireless devices 100 and 200 correspond to the wireless devices 100 and 200 of FIG. 18 and are composed of various elements, components, units / parts, and / or modules. For example, the wireless devices 100 and 200 include a communication unit 110, a control unit 120, a memory unit 130, and an additional element 140. The communication unit includes a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 includes one or more processors 102 and 202 and / or one or more memories 104 and 204 in FIG. 18. For example, the transceiver 114 includes one or more transceivers 106 and 206 and / or one or more antennas 108 and 208 in FIG. 18. The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional element 140 and controls the overall operation of the wireless device. For example, the control unit 120 controls the electrical / mechanical operations of the wireless device based on the programs / codes / instructions / information stored in the memory unit 130. The control unit 120 also transmits the information stored in the memory unit 130 to an external device (e.g., another communication device) via the communication unit 110 via a wireless / wired interface, or stores information received from an external device (e.g., another communication device) via the communication unit 110 via a wireless / wired interface in the memory unit 130.

[0277] The additional element 140 may be configured in various ways depending on the type of wireless device. For example, the additional element 140 may include any one of a power unit / battery, an input / output unit (I / O unit), a driving unit, and a computer unit. Wireless devices may be embodied in the form of, but not limited to, a robot (FIG. 17, 100a), a vehicle (FIG. 17, 100b-1, 100b-2), an XR device (FIG. 17, 100c), a mobile device (FIG. 17, 100d), a home appliance (FIG. 17, 100e), an IoT device (FIG. 17, 100f), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a FinTech device (or financial device), a security device, a climate / environment device, an AI server / device (FIG. 17, 400), a base station (FIG. 17, 200), a network node, etc. Wireless devices may be mobile or fixed depending on the use case / service.

[0278] In FIG. 19, the various elements, components, units / sections and / or modules within the wireless devices 100, 200 are all connected to each other by wired interfaces, or at least some are connected wirelessly by a communication section 110. For example, in the wireless devices 100 and 200, the control unit 120 and the communication unit 110 are connected by wire, and the control unit 120 and the first unit (e.g., 130, 140) are connected wirelessly via the communication unit 110. Furthermore, each element, component, unit / part and / or module in the wireless devices 100 and 200 further includes one or more elements. For example, the control unit 120 is configured with a set of one or more processors. For example, the control unit 120 is configured with a set of a communication control processor, an application processor, an ECU (Electronic Control Unit), a graphics processor, a memory control processor, etc. As another example, the memory unit 130 is configured with a RAM (Random Access Memory), a DRAM (Dynamic RAM), a ROM (Read Only Memory), a flash memory, a volatile memory, a non-volatile memory and / or a combination thereof.

[0286] 20 is a diagram illustrating an example of a vehicle or an autonomous vehicle to which the present invention is applied. The vehicle or the autonomous vehicle may be embodied as a mobile robot, a car, a train, an aerial vehicle (AV), a ship, etc.

[0287] 20, a vehicle or autonomous vehicle 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a drive unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 is configured as part of the communication unit 110. Blocks 110 / 130 / 140a to 140d correspond to blocks 110 / 130 / 140 in FIG. 19, respectively.

[0288] The communication unit 110 transmits and receives signals (e.g., data, control signals, etc.) to and from external devices such as other vehicles, base stations (e.g., base stations, roadside units, etc.), and servers. The control unit 120 controls elements of the vehicle or autonomous vehicle 100 to perform various operations. The control unit 120 includes an ECU (Electronic Control Unit). The driving unit 140a causes the vehicle or autonomous vehicle 100 to move on the ground. The driving unit 140a includes an engine, a motor, a powertrain, wheels, brakes, a steering device, etc. The power supply unit 140b supplies power to the vehicle or autonomous vehicle 100 and includes wired / wireless charging circuits, a battery, etc. The sensor unit 140c can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit 140c includes an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, a vehicle forward / reverse 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 implements technology for maintaining a lane while driving, technology for automatically adjusting speed such as adaptive cruise control, technology for automatically driving along a predetermined route, technology for automatically setting a route and driving when a destination is set, etc.

[0289] For example, the communication unit 110 receives map data, traffic information data, etc. from an external server. The autonomous driving unit 140d generates an autonomous driving route and a driving plan based on the obtained data. The control unit 120 controls the driving unit 140a (e.g., adjusting speed / direction) so that the vehicle or autonomous vehicle 100 moves along the autonomous driving route according to the driving plan. The communication unit 110 aperiodically obtains the latest traffic information data from an external server during autonomous driving and also obtains surrounding traffic information data from surrounding vehicles. In addition, the sensor unit 140c obtains vehicle status and surrounding environment information during autonomous driving. The autonomous driving unit 140d updates the autonomous driving route and driving plan based on the newly obtained data / information. The communication unit 110 transmits information regarding the vehicle position, autonomous driving route, driving plan, etc. to an external server. The external server can predict traffic information data using AI technology based on information collected from the vehicle or autonomous vehicle and provide the predicted traffic information data to the vehicle or autonomous vehicle.

[0290] The above-described embodiments are combinations of the elements and features of the present invention in a predetermined form. Each element or feature should be considered optional unless otherwise explicitly stated. Each element or feature may be implemented without being combined with other elements or features. It is also possible to combine some elements and / or features to form an embodiment of the present invention. The order of operations described in the embodiments of the present invention may be changed. Some elements or features of any embodiment may be included in other embodiments, or may be replaced with corresponding elements or features of other embodiments. It is obvious that claims that are not explicitly cited in the claims may be combined to form an embodiment, or may be included as new claims by amendment after filing.

[0291] It is obvious to those skilled in the art that the present invention can be embodied in other specific forms without departing from the characteristics of the present invention. Therefore, the above detailed description should not be construed as limiting in all respects, but should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention. [Industrial Applicability]

[0292] The present invention can be used in a terminal, a base station or other equipment of a wireless mobile communication system.

Claims

1. A method for transmitting a CSI (Channel Status Information) signal from a base station (BS) to a user equipment (UE), the method comprising: receiving downlink control information (DCI) for reporting CSI (Channel Status Information); receiving, by the UE, at least one channel measurement resource (CMR) from the BS based on the DCI; The UE calculating at least one Precoding Matrix Index (PMI) associated with at least one time instance from a time domain (TD) compression codebook based on the at least one CMR; The UE transmits the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant included in the DCI; The method, wherein the plurality of NZCs have a plurality of priority values ​​determined by sequentially considering the index of a TD basis vector, the index of a frequency domain (FD) basis vector, the index of a spatial domain (SD) basis vector, and the index of a layer.

2. the plurality of NZCs have higher priority values ​​as the index of the TD basis vector increases; Based on the same index of the TD basis vectors, the NZCs have higher priority values ​​as the index of the FD basis vectors increases; Based on the indices of the TD basis vectors being the same and the indices of the FD basis vectors being the same, the NZCs have higher priority values ​​as the indices of the SD basis vectors increase; 2. The method of claim 1, wherein the NZCs have higher priority values ​​as the index of the layer increases based on the indices of the TD basis vectors being identical, the indices of the FD basis vectors being identical, and the indices of the SD basis vectors being identical.

3. The priority value of the NZC is determined based on the following formula: [Formula] l is the layer index, i is the SD basis vector index, f is the FD basis vector index, and t is the TD basis vector index. ν is the number of layers, 2L is the number of SD basis vectors, and N ３ 2. The method of claim 1, wherein π'(t) is a value related to the number of the FD basis vectors, and π'(t) is a function for transforming the index of the TD basis vectors.

4. The method described in claim 1, wherein at least one of the plurality of NZCs is dropped in order of priority values ​​for the plurality of NZCs based on the uplink grant not accommodating the CSI payload.

5. The maximum number of NZCs per layer is determined by multiplying the number of the TD basis vectors, the number of the FD basis vectors, the number of the SD basis vectors, and a constant; The method of claim 1 , wherein the constant is greater than 0 and less than or equal to 1.

6. A UE (User Equipment), at least one processor; at least one computer memory storing instructions that, when executed by the at least one processor, cause the UE to perform an action; The operation is receiving downlink control information (DCI) for reporting channel status information (CSI) from a base station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the DCI; calculating at least one Precoding Matrix Index (PMI) associated with at least one time instance from a time domain (TD) compression codebook based on the at least one CMR; Transmitting the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant included in the DCI; The plurality of NZCs have a plurality of priority values ​​determined by sequentially considering an index of a TD basis vector, an index of a frequency domain (FD) basis vector, an index of a spatial domain (SD) basis vector, and an index of a layer.

7. the plurality of NZCs have higher priority values ​​as the index of the TD basis vector increases; Based on the same index of the TD basis vectors, the NZCs have higher priority values ​​as the index of the FD basis vectors increases; Based on the indices of the TD basis vectors being the same and the indices of the FD basis vectors being the same, the NZCs have higher priority values ​​as the indices of the SD basis vectors increase; 7. The UE of claim 6, wherein the plurality of NZCs have higher priority values ​​as the index of the layer increases based on the indices of the TD basis vectors being the same, the indices of the FD basis vectors being the same, and the indices of the SD basis vectors being the same.

8. The priority value of the NZC is determined based on the following formula: [Formula] l is the layer index, i is the SD basis vector index, f is the FD basis vector index, and t is the TD basis vector index. ν is the number of layers, 2L is the number of SD basis vectors, and N ３ 7. The UE of claim 6, wherein π'(t) is a value related to the number of the FD basis vectors, and π'(t) is a function for transforming the index of the TD basis vector.

9. The UE of claim 6, wherein at least one of the plurality of NZCs is dropped in order of priority values ​​for the plurality of NZCs based on the uplink grant not accommodating the CSI payload.

10. The maximum number of NZCs per layer is determined by multiplying the number of the TD basis vectors, the number of the FD basis vectors, the number of the SD basis vectors, and a constant; The UE of claim 6 , wherein the constant is greater than 0 and less than or equal to 1.

11. A non-transitory computer-readable storage medium containing program instructions, comprising: The program instructions, when executed by at least one processor, cause a user equipment (UE) to perform an operation; The operation is receiving downlink control information (DCI) for reporting channel status information (CSI) from a base station (BS); receiving at least one channel measurement resource (CMR) from the BS based on the DCI; calculating at least one Precoding Matrix Index (PMI) associated with at least one time instance from a time domain (TD) compression codebook based on the at least one CMR; Transmitting the CSI including information on a plurality of non-zero coefficients (NZCs) associated with the at least one PMI based on an uplink grant included in the DCI; A storage medium, wherein the plurality of NZCs have a plurality of priority values ​​determined by sequentially considering the index of a TD basis vector, the index of a FD (Frequency domain) basis vector, the index of a SD (Spatial domain) basis vector, and the index of a layer.

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