Terminal and base station in a communication system

Abstract

The present disclosure provides a terminal and a base station in a communication system. The terminal includes a receiving unit configured to receive, from the base station, first information indicating a first parameter, wherein the first parameter represents a number of candidate transform domain vectors of a precoding matrix on a subcarrier level, and the first parameter has a value less than a number of subcarriers of the communication system; the receiving unit is further configured to receive, from the base station, second information indicating a second parameter, wherein the second parameter represents a number of transform domain vectors of the precoding matrix on the subcarrier level used for determining the transform domain vectors; and a control unit configured to determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

Description

Technical Field

[0001] This disclosure relates to the field of wireless communication, and more specifically to methods performed by a terminal in a communication system, methods performed by a base station in a communication system, and the corresponding terminal and base station. Background Technology

[0002] To improve the throughput of communication systems, multi-antenna technologies, such as Multiple-Input Multiple-Output (MIMO), have been proposed. In scenarios where multi-antenna technologies are applied, precoding techniques are proposed to effectively eliminate multi-user interference, increase system capacity, and reduce the signal processing complexity of the receiver. A codebook is designed to support precoding techniques.

[0003] Release 15 (R15) of 5G New Radio (NR) designed two types of codebooks: Type I and Type II. In the Type I codebook, a wideband codeword is selected, and co-phase for cross-polarization is calculated for each subband. In the Type II codebook, multiple wideband codewords are selected, and complex linear combination (LC) coefficients are calculated for each subband. Furthermore, to reduce the feedback overhead associated with the LC coefficients used for all subbands, Release 16 (R16) of NR designed an enhanced Type II codebook, employing a frequency domain (FD) compression scheme based on Discrete Fourier Transform (DFT) vectors to reduce feedback overhead.

[0004] However, the codebook described above is designed for subbands; therefore, operations based on this codebook are subband-level operations. Specifically, in the example where the receiver is the terminal and the transmitter is the base station, the operation of the terminal determining the Precoding Matrix Indicator (PMI) and feeding it back to the base station is a subband-level operation. Alternatively, operations performed by the terminal based on subband-level information (e.g., the LC coefficients mentioned above) (e.g., compression) are subband-level operations, and the operation of the base station generating the precoding matrix based on the PMI is also a subband-level operation. These operations have a low granularity, limiting the performance of the communication system. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this disclosure proposes that codebook-based operations be performed at the subcarrier-level, thereby improving the performance of the communication system. Accordingly, the operation of the terminal determining the Precoding Matrix Indicator (PMI) and feeding it back to the base station is a subcarrier-level operation or an operation based on subcarrier-level information, and the operation of the base station generating the precoding matrix based on the PMI can also be a subcarrier-level operation. This disclosure also proposes methods executed by the terminal, methods executed by the base station, and the corresponding terminal and base station in this scenario to reduce feedback overhead, thereby further improving the performance of the communication system.

[0006] According to one aspect of this disclosure, a method performed by a terminal in a communication system is provided, comprising: receiving from a base station in the communication system first information for indicating a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for a precoding matrix at the subcarrier level, the value of the first parameter being less than the number of subcarriers in the communication system; receiving from the base station second information for indicating a second parameter, wherein the second parameter represents the number of transform domain vectors for determining a precoding matrix at the subcarrier level; and determining the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

[0007] According to one example of this disclosure, the first information includes the first parameter.

[0008] According to one example of this disclosure, the second information includes the second parameter.

[0009] According to one example of this disclosure, the second information is used to indicate a first factor corresponding to the value of the second parameter.

[0010] According to one example of this disclosure, the method further includes: determining the value of the second parameter based on the first factor and the first parameter.

[0011] According to one example of this disclosure, the method further includes: determining precoding matrix indication information based at least on the first information and the second information.

[0012] According to one example of this disclosure, the method further includes: determining precoding matrix indication information based at least on the determined transform domain vector.

[0013] According to one example of this disclosure, the method further includes: receiving indication information from the base station for indicating a subset of the candidate transform domain vectors, and determining from the subset the number of transform domain vectors indicated by the second information.

[0014] According to one example of this disclosure, the indication information includes third information for indicating a third parameter, wherein the value of the third parameter represents the number of vectors included in the subset of the candidate transform domain vectors.

[0015] According to one example of this disclosure, the third information includes the third parameter.

[0016] According to one example of this disclosure, the indication information includes fourth information for indicating a fourth parameter, wherein the fourth parameter is used to determine the vectors included in the subset of the candidate transform domain vectors.

[0017] According to one example of this disclosure, the fourth information includes the fourth parameter.

[0018] According to one example of this disclosure, the method further includes: sending the precoding matrix indication information to the base station.

[0019] According to one example of this disclosure, the precoding matrix indication information is a precoding matrix indicator.

[0020] According to one example of this disclosure, the method further includes: sending rank indication information to the base station, wherein the rank indication information is used to indicate the rank for the terminal, and the value of the rank for the terminal is greater than or equal to four.

[0021] According to another aspect of this disclosure, a method performed by a base station in a communication system is provided, comprising: determining a first parameter, wherein the first parameter represents the number of candidate transform domain vectors of a precoding matrix at the subcarrier level, the value of the first parameter being less than the number of subcarriers in the communication system; determining a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level; and sending first information indicating the first parameter and second information indicating the second parameter to a terminal in the communication system.

[0022] According to one example of this disclosure, the first information includes the first parameter.

[0023] According to one example of this disclosure, the second information includes the second parameter.

[0024] According to one example of this disclosure, the second information is used to indicate a first factor corresponding to the value of the second parameter.

[0025] According to one example of this disclosure, the method further includes: determining a first set based at least on the value of the rank corresponding to the terminal, the number of beams, and the first parameter, wherein the first set includes one or more first factors; and determining a first factor corresponding to the value of the second parameter from the first set based on the value of the first parameter and the value of the second parameter.

[0026] According to an example of this disclosure, wherein the value of the first parameter is greater than a preset threshold, and the preset threshold is less than the number of subcarriers of the communication system, the method further includes: sending indication information to the terminal for indicating a subset of the candidate transform domain vectors, so that the terminal determines from the subset the number of transform domain vectors indicated by the second information.

[0027] According to one example of this disclosure, the indication information includes third information for indicating a third parameter, wherein the value of the third parameter represents the number of vectors included in the subset of the candidate transform domain vectors.

[0028] According to one example of this disclosure, the third information includes the third parameter.

[0029] According to one example of this disclosure, the indication information includes fourth information for indicating a fourth parameter, wherein the fourth parameter is used to determine the vectors included in the subset of the candidate transform domain vectors.

[0030] According to one example of this disclosure, the fourth information includes the fourth parameter.

[0031] According to one example of this disclosure, the method further includes: receiving the precoding matrix indication information from the terminal; and generating a subcarrier-level precoding matrix based on the precoding matrix indication information.

[0032] According to one example of this disclosure, the precoding matrix indication information is a precoding matrix indicator.

[0033] According to another aspect of this disclosure, a terminal is provided, comprising: a receiving unit configured to receive from a base station in the communication system first information indicating a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for a precoding matrix at the subcarrier level, the value of the first parameter being less than the number of subcarriers in the communication system; the receiving unit further configured to receive from the base station second information indicating a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level; and a control unit configured to determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

[0034] According to one example of this disclosure, the first information includes the first parameter.

[0035] According to one example of this disclosure, the second information includes the second parameter.

[0036] According to one example of this disclosure, the second information is used to indicate a first factor corresponding to the value of the second parameter.

[0037] According to one example of this disclosure, the control unit is further configured to determine the value of the second parameter based on the first factor and the first parameter.

[0038] According to one example of this disclosure, the control unit is configured to determine precoding matrix indication information based at least on the first information and the second information.

[0039] According to one example of this disclosure, the control unit is configured to determine the precoding matrix indication information based at least on the determined transform domain vector.

[0040] According to one example of this disclosure, the receiving unit is further configured to receive indication information from the base station for indicating a subset of the candidate transform domain vectors, and the control unit is configured to determine from the subset the number of transform domain vectors indicated by the second information.

[0041] According to one example of this disclosure, the indication information includes third information for indicating a third parameter, wherein the value of the third parameter represents the number of vectors included in the subset of the candidate transform domain vectors.

[0042] According to one example of this disclosure, the third information includes the third parameter.

[0043] According to one example of this disclosure, the indication information includes fourth information for indicating a fourth parameter, wherein the fourth parameter is used to determine the vectors included in the subset of the candidate transform domain vectors.

[0044] According to one example of this disclosure, the fourth information includes the fourth parameter.

[0045] According to one example of this disclosure, the terminal further includes a transmitting unit configured to transmit the precoding matrix indication information to the base station.

[0046] According to one example of this disclosure, the precoding matrix indication information is a precoding matrix indicator.

[0047] According to one example of this disclosure, the terminal further includes: a transmitting unit configured to transmit rank indication information to the base station, wherein the rank indication information is used to indicate the rank for the terminal, and the value of the rank for the terminal is greater than or equal to four.

[0048] According to another aspect of this disclosure, a base station is provided, comprising: a control unit configured to determine a first parameter, wherein the first parameter represents the number of candidate transform domain vectors of a precoding matrix at the subcarrier level, the value of the first parameter being less than the number of subcarriers in the communication system; the control unit is further configured to determine a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level; and a transmission unit configured to transmit first information indicating the first parameter and second information indicating the second parameter to a terminal in the communication system.

[0049] According to one example of this disclosure, the first information includes the first parameter.

[0050] According to one example of this disclosure, the second information includes the second parameter.

[0051] According to one example of this disclosure, the second information is used to indicate a first factor corresponding to the value of the second parameter.

[0052] According to one example of this disclosure, the control unit is further configured to determine a first set based at least on the value of the rank corresponding to the terminal, the number of beams, and the first parameter, wherein the first set includes one or more first factors; and to determine a first factor corresponding to the value of the second parameter from the first set based on the value of the first parameter and the value of the second parameter.

[0053] According to one example of this disclosure, wherein the value of the first parameter is greater than a preset threshold, the preset threshold being less than the number of subcarriers of the communication system, the transmitting unit is further configured to send indication information to the terminal for indicating a subset of the candidate transform domain vectors, so that the terminal determines from the subset the number of transform domain vectors indicated by the second information.

[0054] According to one example of this disclosure, the indication information includes third information for indicating a third parameter, wherein the value of the third parameter represents the number of vectors included in the subset of the candidate transform domain vectors.

[0055] According to one example of this disclosure, the third information includes the third parameter.

[0056] According to one example of this disclosure, the indication information includes fourth information for indicating a fourth parameter, wherein the fourth parameter is used to determine the vectors included in the subset of the candidate transform domain vectors.

[0057] According to one example of this disclosure, the fourth information includes the fourth parameter.

[0058] According to one example of this disclosure, the base station further includes: a receiving unit configured to receive the precoding matrix indication information from the terminal; the control unit is further configured to generate a subcarrier-level precoding matrix based on the precoding matrix indication information.

[0059] According to one example of this disclosure, the precoding matrix indication information is a precoding matrix indicator.

[0060] According to the methods performed by the terminal and the methods performed by the base station, as well as the corresponding terminal and base station, in the case of applying subcarrier-level precoding technology, the feedback overhead related to precoding from the terminal to the base station can be reduced, thereby improving the performance of the communication system. Attached Figure Description

[0061] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to offer a further understanding of the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0062] Figure 1 A schematic diagram of a wireless communication system in which embodiments of the present disclosure can be applied is shown.

[0063] Figure 2 A flowchart of a method executed by a terminal according to an embodiment of the present disclosure is shown.

[0064] Figure 3A This is a schematic diagram of a terminal directly selecting a transform domain vector from candidate transform domain vectors according to an embodiment of the present disclosure.

[0065] Figure 3B This is a schematic diagram of a terminal selecting a transform domain vector from a subset of candidate transform domain vectors according to an embodiment of the present disclosure.

[0066] Figure 4 A flowchart of a method performed by a base station according to an embodiment of the present disclosure is shown.

[0067] Figure 5 A schematic diagram of the structure of a terminal according to an embodiment of the present disclosure is shown.

[0068] Figure 6 A schematic diagram of the structure of a base station according to an embodiment of the present disclosure is shown.

[0069] Figure 7 This is a schematic diagram of the hardware structure of a communication device according to an embodiment of the present disclosure. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same elements throughout. It should be understood that the embodiments described herein are merely illustrative and should not be construed as limiting the scope of this disclosure.

[0071] First, refer to Figure 1 This describes a wireless communication system in which embodiments of the present disclosure can be applied. Figure 1 A schematic diagram of a wireless communication system in which embodiments of the present disclosure can be applied is shown. Figure 1 The wireless communication system 100 shown can be a 5G communication system or any other type of wireless communication system, such as a 6G communication system. In the following description, an embodiment of this disclosure is illustrated using a 5G communication system as an example; however, it should be understood that the following description is also applicable to other types of wireless communication systems.

[0072] like Figure 1 As shown, the wireless communication system 100 may include a base station 110 and a terminal 120, whereby the base station 110 is the serving base station of the terminal 120. The base station 110 may send a Channel State Information Reference Signal (CSI-RS) to the terminal 120. The terminal 120 may measure the CSI-RS and determine the channel condition and precoding matrix indicator (PMI) based on the measurement results. The terminal 120 may include the PMI in its CSI report and send the CSI report to the base station 110, thereby providing PMI feedback to the base station 110. The base station 110 may generate a precoding matrix based on the PMI and then apply this precoding matrix in the downlink transmission from the base station 110 to the terminal 120.

[0073] The base stations described herein can provide communication coverage for specific geographical areas and may be referred to as cells, Node Bs, gNBs, 5G Node Bs, access points, and / or transmit / receive points, etc. The terminals described herein may include various types of terminals, such as user equipment (UEs), mobile terminals (or mobile stations), or fixed terminals; however, for convenience, the terms "terminal" and "UE" are sometimes used interchangeably below.

[0074] It needs to be recognized that, although Figure 1 Only one base station and one terminal are shown, but a wireless communication system may include more base stations and / or more terminals, and one base station may serve multiple terminals, and one terminal may be served by multiple base stations.

[0075] In the process of determining the PMI by the terminal described above, the terminal uses the corresponding codebook according to its configuration. In the prior art, the codebook is designed for the subband of the wireless communication system, and correspondingly, precoding and / or CSI feedback are subband-level operations. These operations have low granularity, which limits the performance of the communication system.

[0076] To overcome the shortcomings of existing technologies, this disclosure proposes subcarrier-level precoding and / or CSI feedback, which improves operational granularity and thus enhances the performance of the communication system. Specifically, subcarrier-level precoding and / or CSI feedback can be implemented based on existing enhanced type-2 codebooks. For example, subband-related parameters and operations involved in the application of existing enhanced type-2 codebooks can be modified to subcarrier-related parameters and operations, which can be called an enhanced frequency domain (eFD) compression scheme. Furthermore, LC coefficients can be jointly designed in the spatial and frequency domains, and subband-related parameters and operations involved in the application of existing enhanced type-2 codebooks can be modified to subcarrier-related parameters and operations, which can be called an enhanced transform domain precoding (eTDP) compression scheme, where the transform domain refers to the domain transformed from the frequency domain, such as the delay domain.

[0077] In wireless communication systems that support subcarrier-level precoding and / or CSI feedback, the terminal can select a second number of transform domain vectors from a first number of candidate transform domain vectors for each layer and report the selected second number of transform domain vectors to the base station (e.g., using information indicating the selected second number of transform domain vectors as part of a precoding matrix indicator). In subband-level precoding techniques, the number of candidate transform domain vectors can be determined based on the number of subbands. Similar to subband-level precoding techniques, in subcarrier-level precoding techniques, the first number can be the number of subcarriers in the wireless communication system. The second number is a value determined at least based on the rank corresponding to the terminal. However, since a subband can include multiple subcarriers, the number of subcarriers in the wireless communication system is larger than the number of subbands, i.e., the first number mentioned above is larger. When the first number is large, selecting a second number of transform domain vectors from the first number of candidate transform domain vectors and feeding back the selected second number of transform domain vectors to the base station results in significant feedback overhead. Therefore, reducing feedback overhead is an aspect that needs to be considered.

[0078] The specific implementation methods of the technical solution disclosed herein for reducing feedback overhead will be described from the perspectives of the terminal and the base station, respectively.

[0079] First, combined Figure 2 This describes a method executed by a terminal according to embodiments of the present disclosure. Figure 2 A flowchart of a method 200 executed by a terminal according to an embodiment of the present disclosure is shown. Figure 2 As shown, in step S201, the terminal receives first information from the base station in the communication system to indicate a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for the precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system. In step S202, the terminal receives second information from the base station to indicate a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level. Then, in step S203, the terminal determines the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

[0080] This disclosure reduces the number of candidate transform domain vectors for the subcarrier-level precoding matrix from the number of subcarriers in the communication system (e.g., N³) to the value of the first parameter by introducing a new parameter, namely the first parameter. Because the number of candidate transform domain vectors for the subcarrier-level precoding matrix is ​​reduced, the feedback overhead resulting from selecting the transform domain vectors from the candidate vectors to determine the subcarrier-level precoding matrix and feeding the selected transform domain vectors back to the base station is correspondingly reduced.

[0081] In this disclosure, the subcarrier-level precoding matrix differs from the subband-level precoding matrix in the prior art. Specifically, in the prior art, the codebook used for precoding techniques and / or CSI feedback is a codebook designed for subbands; therefore, the precoding matrix determined based on this codebook is a subband-level precoding matrix. However, in this disclosure, the codebook used for precoding techniques and / or CSI feedback is a codebook designed for subcarriers; therefore, the precoding matrix determined based on this codebook is a subcarrier-level precoding matrix. In this disclosure, the subcarrier-level precoding matrix can also be referred to as a precoding matrix for subcarriers, or a precoding matrix specific to subcarriers.

[0082] According to one example of this disclosure, the first information in step S201 may include a first parameter. For example, the first information may only include the first parameter, that is, the first information is the first parameter. As another example, the first information may include not only the first parameter, but also other information (e.g., other configuration information sent by the base station to the terminal).

[0083] Furthermore, according to an example of this disclosure, the first information in step S201 can also be used to indicate the value range of the first parameter. In this example, the terminal can determine the value range of the first parameter based on the first information, select a value from the value range, and use the selected value as the value of the first parameter.

[0084] Furthermore, the first parameter in step S201 can be represented as M. max Its value is less than the number of subcarriers in the communication system (i.e., N3 mentioned above) and greater than the number of subbands in the communication system (e.g., it can be represented as N0). Alternatively, the value of the first parameter in step S201 can be less than the number of subcarriers (N3) in the communication system and less than or equal to the number of subbands (N0) in the communication system.

[0085] Furthermore, in this disclosure, the transform domain can be the domain after transforming the frequency domain, such as the delay domain. The candidate transform domain vector in step S201 can be a Discrete Fourier Transform (DFT) vector.

[0086] Furthermore, the base station can send the first information to the terminal via higher-layer signaling. In examples where the higher-layer signaling is Radio Resource Control (RRC) signaling or Media Access Control (MAC) Control Element (CE), the base station can send the first information to the terminal via RRC signaling or MAC CE. Accordingly, in step S201, the terminal can receive the first information from the base station via RRC signaling or MAC CE.

[0087] Furthermore, the base station can send the first information to the terminal via lower-layer signaling. In the example where the lower-layer signaling is Downlink Control Information (DCI), the base station can send the first information to the terminal via DCI. Accordingly, in step S201, the terminal can receive the first information from the base station via DCI.

[0088] In this disclosure, the base station can notify the terminal not only of the number (M) of candidate transform domain vectors of the precoding matrix at the subcarrier level. max Furthermore, it can notify the terminal of the number of transform domain vectors it should select from the candidate transform domain vectors, so that the terminal can determine the precoding matrix indication information. Therefore, in step S202, the terminal receives second information from the base station indicating the second parameter, wherein the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level, and the value of the second parameter is less than the value of the first parameter. The second parameter can be represented as M. v And it is a positive integer, where v represents the rank corresponding to the terminal and is a positive integer.

[0089] Furthermore, according to an example of this disclosure, the second information in step S202 can explicitly indicate the second parameter. For example, the second information may include the second parameter. In this example, the base station can send the second information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, in step S202, the terminal can receive the second information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the second parameter. Alternatively, the base station can send the second information to the terminal via lower-layer signaling such as DCI. Accordingly, in step S202, the terminal can receive the second information from the base station via lower-layer signaling such as DCI to obtain the second parameter.

[0090] According to another example of this disclosure, the second information in step S202 can implicitly indicate the second parameter. For example, the second information can be used to indicate a first factor corresponding to the value of the second parameter. The first factor can be represented as p vIts value is greater than zero and less than one, that is, 0 < p v <1. In this example, the base station determines the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level. max And the number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v After that, the base station can determine the relationship with M according to preset rules. v The corresponding first factor (p) v For example, the base station can determine the number of candidate transform domain vectors (M) based on the precoding matrix at the subcarrier level. max The number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v ), and the following formula (1), determine the relationship with M from the set of the first factors. v The corresponding first factor (p) v ):

[0091]

[0092] Alternatively, in this example, the base station can determine the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level. max ) and the first factor (p v This eliminates the need to determine the number (M) of transform domain vectors the terminal should select from the candidate transform domain vectors. v For example, a base station can determine a first factor (p) from the set of first factors. v ), and notify the terminal.

[0093] It should be recognized that step S202 can be performed after step S201, or before step S201, or simultaneously with step S201. Figure 2 The diagram only shows the execution of step S202 after step S201. Examples of executing step S202 before step S201 and examples of executing steps S201 and S202 simultaneously are not shown.

[0094] Furthermore, the transform domain vector used in step S202 to determine the precoding matrix at the subcarrier level, i.e., the transform domain vector selected by the terminal from the candidate transform domain vectors, can also be called the transform domain basis vector. In the example where the transform domain vector is a DFT vector, it can also be called the DFT basis vector. For convenience, these terms can be used interchangeably.

[0095] Furthermore, in determining the precoding matrix, in addition to the transform domain vector in step S202, multiple spatial domain vectors (also referred to as spatial beams, spatial codewords, wideband codewords, or wideband spatial codewords, etc.) are needed, for example, L spatial domain vectors, where L is a positive integer. Each spatial domain vector has frequency domain weighting coefficients. The transform domain vector in step S202 can be used to transform and compress the frequency domain weighting coefficients of the spatial domain vectors (for example, first transforming them to the delay domain, and then compressing them in that delay domain). However, since the spatial domain vectors are not related to the technical solution of this disclosure, this disclosure omits descriptions related to spatial domain vectors.

[0096] Furthermore, as described above, the second parameter can be implicitly indicated by a first factor corresponding to the value of the second parameter. In this case, method 200 may also include step S204. Step S204 may be performed after step S202 and before step S203. In step S204, the terminal can determine the value of the second parameter based on the first factor and the first parameter. Specifically, the terminal can determine the value of the second parameter based on the value of the first factor and the value of the first parameter. For example, the terminal can determine the value of the second parameter using formula (1) described above.

[0097] After step S204, the terminal can determine the precoding matrix indication information based at least on the first information and the second information. For example, the terminal can determine the precoding matrix indication information based at least on the first parameter indicated by the first information and the second parameter indicated by the second information.

[0098] Alternatively, after step S204, the terminal executes step S203. In step S203, the terminal selects the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information. For example, the terminal can select the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information based on the position of the channel tap (e.g., the terminal can estimate the position of the channel tap based on downlink channel information obtained by measuring CSI-RS) or other selection criteria or methods. For example, the terminal can select the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information based on the position of the channel tap. max M is selected from the candidate transform domain vectors. v A transform domain vector. Through step S203, the terminal can determine the precoding matrix indication information, at least based on the selected transform domain vector, in step S207, which will be described below. That is, the terminal can determine the precoding matrix indication information from the M transform domain vector of the subcarrier level precoding matrix. max M is selected from the candidate transform domain vectors. v Transformation domain vectors, and at least according to the chosen M vThe transform domain vector is used to determine the precoding matrix indication information.

[0099] When the value of the first parameter indicated by the first information is small, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is small, the terminal can directly access the M. max M is selected from the candidate transform domain vectors. v The number of candidate transform domain vectors. When the value of the first parameter indicated by the first information is large, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is large, the terminal can determine an intermediate subset (InS or subset) of candidate transform domain vectors and select M from this subset. v M transform domain vectors are used to further reduce feedback overhead. For example, the terminal can receive indication information from the base station to indicate a subset of the candidate transform domain vectors, and determine the number of transform domain vectors indicated by the second information from the subset (i.e., select M from the subset). v (a transform domain vector).

[0100] For example, the terminal can determine whether the value of the first parameter indicated by the first information is less than a preset threshold, which can be less than the number of subcarriers in the communication system (i.e., N3 mentioned above). When the value of the first parameter indicated by the first information is less than or equal to the preset threshold, the terminal can directly select from M... max M is selected from the candidate transform domain vectors. v A subset of candidate transform domain vectors. When the value of the first parameter indicated by the first information is greater than a preset threshold, the terminal can determine a subset (InS) of candidate transform domain vectors and select M from that subset. v A transform domain vector is used to further reduce feedback overhead. In the example where the preset threshold is 19, when the value of the first parameter indicated by the first information is less than or equal to the preset threshold (i.e., M... max When ≤19), the terminal can directly access M. max M is selected from the candidate transform domain vectors. v A transform domain vector; when the value of the first parameter indicated by the first information is greater than a preset threshold (i.e., M) max When >19), the terminal can determine a subset (InS) of candidate transform domain vectors and select M from that subset. v A transform domain vector is used to further reduce feedback overhead.

[0101] According to an example of this disclosure, when determining a subset (InS) of candidate transform domain vectors, the terminal requires two more parameters: a third parameter and a fourth parameter. The third parameter can be represented as N3. ’Its value can represent the number of vectors included in the subset (InS) of candidate transform domain vectors (also known as the size of the subset), or the number of subsets (InS) of candidate transform domain vectors. If the number of vectors included in the subset (InS) of candidate transform domain vectors is greater than the number of transform domain vectors the terminal should select from the candidate transform domain vectors (M... v For example, it can be 2M. v In other words, N3 ’ It can be equal to 2M v Furthermore, the fourth parameter can be used to determine the subset of candidate transform domain vectors, which can be represented as M. initial The range of values ​​for the fourth parameter can be specified by wireless communication standards (e.g., 3GPP standards), and this range can include multiple values ​​for the fourth parameter. For example, the range of values ​​for the fourth parameter can be related to the third parameter, such as M. initial ∈{-N3 ’ +1, -N3 ’ +2, ..., 0}.

[0102] The terminal and the base station can negotiate a third parameter (N3) in advance. ’ The value of ) and the fourth parameter (M) initial The values ​​of the third parameter and the fourth parameter are determined according to the first example of this disclosure. The terminal can determine the values ​​of the third parameter and the fourth parameter and report these values ​​to the base station. According to the second example of this disclosure, the base station can determine the values ​​of the third parameter and the fourth parameter and notify the terminal of these values. According to the third example of this disclosure, the terminal can determine the value of the third parameter and report it to the base station, and the base station can determine the value of the fourth parameter and notify the terminal of this value. According to the fourth example of this disclosure, the base station can determine the value of the third parameter and notify the terminal of this value, and the terminal can determine the value of the fourth parameter and report it to the base station.

[0103] Determine the third parameter (N3) at the terminal. ’ The value of ) and the fourth parameter (M) initialIn the first example of the value of the third parameter, the wireless communication standard specification (e.g., the 3GPP standard specification) can define a range of values ​​for the third parameter, which can include multiple values ​​for the third parameter. The terminal can select one value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. Furthermore, the terminal can report the selected value of the third parameter to the base station. For example, the terminal can include the value of the third parameter as part of the PMI and feed the PMI back to the base station, thereby realizing the terminal reporting the value of the third parameter to the base station. Similarly, the terminal can select one value from the range of values ​​for the fourth parameter and use the selected value as the value of the fourth parameter. Furthermore, the terminal can report the selected value of the fourth parameter to the base station. For example, the terminal can include the value of the fourth parameter as part of the PMI and feed the PMI back to the base station, thereby realizing the terminal reporting the value of the fourth parameter to the base station. Additionally, in this first example, since the range of values ​​for the third parameter can include multiple values ​​for the third parameter, and the range of values ​​for the fourth parameter can include multiple values ​​for the fourth parameter, the terminal can determine multiple subsets. The terminal can select one subset from these multiple subsets, and then select M from the selected subset. v Transformed domain vectors.

[0104] Furthermore, the base station determines the third parameter (N3) ’ The value of ) and the fourth parameter (M) initial In the second example of the value of ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’ The base station can select a value from the range of values ​​for the third parameter, which may include multiple values ​​for the third parameter. The base station can then notify the terminal of the selected value of the third parameter. Additionally, the base station can select a value from the range of values ​​for the fourth parameter (M). initial The base station selects a value from the range of possible values ​​for the fourth parameter and uses this selected value as the fourth parameter value. The base station can then notify the terminal of the selected fourth parameter value. Furthermore, in this second example, since the base station notifies the terminal of both the selected third and fourth parameter values, the terminal can determine only one subset. The terminal can then select M from the determined subset. v Transformed domain vectors.

[0105] For example, the base station can use the third parameter (N3) to indicate the third parameter. ’ The third information and the information used to indicate the fourth parameter (M) initialThe fourth information is included in an indication message, which is then sent to the terminal. For example, the base station may send indication information to the terminal to indicate a subset of candidate transform domain vectors, so that the terminal can determine the number of transform domain vectors indicated by the second information from the subset. This indication information may include information indicating the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth information is the third information, which may include a third parameter. The fourth information may include a fourth parameter. Accordingly, the terminal can receive indication information from the base station for indicating a subset of candidate transform domain vectors, and determine the number of transform domain vectors indicated by the second information from the subset.

[0106] For example, the base station can send instructions to the terminal to indicate the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0107] Specifically, the base station can send a signal to the terminal indicating a third parameter (N3). ’ The third information may include a third parameter. Accordingly, the terminal can receive third information from the base station indicating the third parameter, and obtain the third parameter based on the third information, thereby determining the value of the third parameter (e.g., Figure 2 (Step S205 in the above steps). For example, the base station can send third information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal can receive the third information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the third parameter and determine the value of the third parameter. Alternatively, the base station can send the third information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal can receive the third information from the base station via lower-layer signaling such as DCI to obtain the third parameter and determine the value of the third parameter.

[0108] In addition, the base station can send a fourth parameter (M) to the terminal. initial The fourth information may include a fourth parameter. Accordingly, the terminal can receive the fourth information from the base station indicating the fourth parameter, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter (e.g., Figure 2(Step S206 in the above steps). For example, the base station can send the fourth information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal can receive the fourth information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the fourth parameter and determine the value of the fourth parameter. Alternatively, the base station can send the fourth information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal can receive the fourth information from the base station via lower-layer signaling such as DCI to obtain the fourth parameter and determine the value of the fourth parameter.

[0109] In addition, the third parameter (N3) is determined at the terminal. ’ The value of ) and the base station determines the fourth parameter (M) initial In the third example of the value of ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’ The range of values ​​for the third parameter can include multiple values. The terminal can select one value from this range and use it as the value of the third parameter. Furthermore, the terminal can report the selected value of the third parameter to the base station. For example, the terminal can include the value of the third parameter as part of the PMI and feed it back to the base station, thus enabling the terminal to report the value of the third parameter to the base station. Additionally, the base station can select a value from the fourth parameter (M... initial The base station selects a value from the range of possible values ​​for the fourth parameter and uses the selected value as the value of the fourth parameter. The base station can notify the terminal of the selected value of the fourth parameter. For example, the base station can send fourth information indicating the fourth parameter to the terminal via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI. This fourth information may include the fourth parameter. Accordingly, the terminal can receive the fourth information indicating the fourth parameter from the base station via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter. In addition, in this third example, although the base station notifies the terminal of the selected value of the fourth parameter, since the range of possible values ​​for the third parameter may include multiple values ​​of the third parameter, the terminal can still determine multiple subsets. The terminal can select one subset from these multiple subsets, and then select M from the selected subset. v Transformed domain vectors.

[0110] Furthermore, the base station determines the third parameter (N3) ’ The value of ) and the terminal determines the fourth parameter (M) initial In the fourth example of the possible values ​​for ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’The base station can select a value from the range of values ​​for the third parameter, which may include multiple values ​​for the third parameter. The base station can then select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. The base station can notify the terminal of the selected value of the third parameter. For example, the base station can send third information indicating the third parameter to the terminal via higher-layer signaling such as RRC or MAC CE, or lower-layer signaling such as DCI. This third information may include the third parameter. Accordingly, the terminal can receive the third information indicating the third parameter from the base station via higher-layer signaling such as RRC or MAC CE, or lower-layer signaling such as DCI, and obtain the third parameter based on the third information, thereby determining the value of the third parameter. Furthermore, the terminal can select a value from the range of values ​​for the fourth parameter and use the selected value as the value of the fourth parameter. Additionally, the terminal can report the selected value of the fourth parameter to the base station. For example, the terminal can include the value of the fourth parameter as part of the PMI and feed the PMI back to the base station, thereby enabling the terminal to report the value of the fourth parameter to the base station. Furthermore, in this fourth example, although the base station informs the terminal of the value of the selected third parameter, since the range of values ​​for the fourth parameter can include multiple values, the terminal can still determine multiple subsets. The terminal can select one subset from these multiple subsets, and then select M from the selected subset. v Transformed domain vectors.

[0111] In the first to fourth examples above, wireless communication standard specifications (e.g., 3GPP standard specifications) define a third parameter (N3). ’ The range of values ​​for ). According to another example of this disclosure, wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’ The value of a parameter (e.g., a specific value), rather than a range of values. For example, wireless communication standards (e.g., 3GPP standards) may specify a third parameter (N3). ’ The value of ) is the second parameter (M) v The value of ) must be an integer multiple of its value. For example, wireless communication standards (e.g., 3GPP standards) may specify a third parameter (N3). ’ The value of ) is the second parameter (M) v The value of N is twice that of N3. ’ =2M v .

[0112] The third parameter (N3) is specified in wireless communication standards (e.g., 3GPP standards). ’In cases where the value of the third parameter is specified, the terminal and the base station can determine the value of the third parameter according to the provisions of the wireless communication standard. Therefore, the terminal does not need to report the value of the third parameter to the base station, or the base station does not need to notify the terminal of the value of the third parameter.

[0113] Similarly, in the first to fourth examples above, wireless communication standard specifications (e.g., 3GPP standard specifications) define a fourth parameter (M). initial The range of values ​​for ). According to another example of this disclosure, wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a fourth parameter (M). initial The fourth parameter is a specific value (e.g., a particular value), not a range of values. In this case, the terminal and the base station can determine the value of the fourth parameter according to the specifications of the wireless communication standard. Therefore, the terminal does not need to report the value of the fourth parameter to the base station, or the base station does not need to notify the terminal of the value of the fourth parameter.

[0114] The third parameter (N3) was obtained at the terminal. ’ ) and the fourth parameter (M) initial After that, the terminal can perform step S203 according to the third parameter and the fourth parameter, that is, determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

[0115] For example, firstly, the terminal can generate a subset (InS) of candidate transform domain vectors from the number of candidate transform domain vectors indicated by the first information, based on the third parameter and the fourth parameter. For example, the terminal can generate the subset (InS) of candidate transform domain vectors according to the following formula (2):

[0116] InS = mod(M) initial +n, M max ) Formula (2)

[0117] Where n = 0, 1, 2, ..., (N3) ’ -1).

[0118] According to formula (2), when the fourth parameter (M) initial When the value of the fourth parameter is specific, a subset (InS) of candidate transform domain vectors corresponding to that specific value is generated. Therefore, when the fourth parameter has multiple possible values, multiple subsets (InS) of candidate transform domain vectors can be generated accordingly. Similarly, when the third parameter has multiple possible values ​​and / or the fourth parameter has multiple possible values, multiple subsets (InS) of candidate transform domain vectors can be generated accordingly. Furthermore, the number of vectors included in each subset (InS) is equal to the number of vectors in the third parameter (N3). ’ ).

[0119] Furthermore, when the third parameter (N3) ’ The value of ) is M max At that time, the subset determined by formula (2) is actually M. max There are several candidate transform domain vectors. In this case, only one subset includes M. max Candidate transform domain vectors.

[0120] The terminal can then determine the transform domain vector of the quantity indicated by the second information from the subset (InS). For example, the terminal can select M from the subset (InS). v A transform domain vector. For example, certain bits (e.g.) can be used. A (bit) indicator is used to indicate which M the terminal selects from the subset (InS). v Transformed domain vectors.

[0121] The following is combined Figure 3A and Figure 3B To describe again the terminal directly from M max M is selected from the candidate transform domain vectors. v A set of transform domain vectors, and the terminal selects M from a subset (InS) of candidate transform domain vectors. v A schematic diagram of a transform domain vector. Figure 3A The terminal according to the embodiments of this disclosure directly from M max M is selected from the candidate transform domain vectors. v A schematic diagram of a transform domain vector. Figure 3B According to embodiments of this disclosure, the terminal selects M from a subset (InS) of candidate transform domain vectors. v A schematic diagram of a transform domain vector.

[0122] exist Figure 3A In the example shown, the transform domain vector is the DFT vector. Figure 3A As shown, the horizontal axis represents the indices of all DFT vectors corresponding to the number of subcarriers in the communication system or the size of the Fast Fourier Transform (FFT). The vertical arrows indicate the positions of the channel taps. The number of all DFT vectors corresponding to the number of subcarriers in the communication system is N³, with indices of 0, 1, 2, ..., (N³ - 1). All DFT vectors corresponding to the number of subcarriers in the communication system include candidate DFT vectors used to determine the precoding matrix at the subcarrier level. The number of candidate DFT vectors used to determine the precoding matrix at the subcarrier level is M. max Their indices are 0, 1, 2, ..., (M) max -1). The terminal is from this M maxM is selected from the candidate DFT vectors that corresponds to the position of the channel tap. v DFT basis vectors. and Figure 3A The index corresponding to the vertical arrow in the diagram indicates the terminal's origin from that M. max The index of the DFT basis vector selected from the candidate DFT vectors.

[0123] exist Figure 3B In the example shown, the transform domain vector is also a DFT vector. Figure 3B As shown, the horizontal axis represents the index of all DFT vectors corresponding to the number of subcarriers or the FFT size of the communication system. The vertical arrows indicate the positions of the channel taps. The number of all DFT vectors corresponding to the number of subcarriers in the communication system is N³, with indices of 0, 1, 2, ..., (N³ - 1). All DFT vectors corresponding to the number of subcarriers in the communication system include candidate DFT vectors used to determine the precoding matrix at the subcarrier level. The number of candidate DFT vectors used to determine the precoding matrix at the subcarrier level is M. max Their indices are 0, 1, 2, ..., (M) max -1). The terminal determined that M max A subset (InS) of candidate DFT vectors is selected, and M corresponding to the position of the channel tap is chosen from this subset. v DFT basis vectors. and Figure 3B The index corresponding to the vertical arrow in the diagram represents the index of the DFT basis vector selected by the terminal from that subset.

[0124] return Figure 2 Method 200 may further include step S207. For example, step S207 may be performed after step S203. In step S207, the terminal can determine the precoding matrix indication information based on the transform domain vectors determined by step S203. That is, after the terminal selects the number of transform domain vectors indicated by the second information (i.e., selects M), the precoding matrix indication information is determined. v After the number of transform domain vectors, the terminal can determine the precoding matrix indication information based on the number of transform domain vectors indicated by the selected second information.

[0125] In this disclosure, the precoding matrix indication information can be a PMI. The terminal can generate the PMI according to a conventional method of determining the PMI based on transform domain basis vectors (e.g., the method specified in 3GPP standards). For example, the precoding matrix indication information may include M... v The index of a transform domain vector, or the M v The quantization information of the indices of each transform domain vector. Furthermore, when the number of candidate transform domain vectors M... maxWhen the value is specific, one or more bits corresponding to that specific value can be used to indicate each transform domain vector. For example, when the number of candidate transform domain vectors M max When the value is 16, 4 bits can be used to indicate each transform domain vector. For example, when the number of candidate transform domain vectors M... max When the value is 64, 6 bits can be used to indicate each transform domain vector.

[0126] Furthermore, after step S202, method 200 may also include step S208. In step S208, the terminal may send precoding matrix indication information to the base station. In the example where the precoding matrix indication information is PMI, the terminal may include the PMI in the CSI report and send the CSI report to the base station, thereby realizing the feedback of PMI to the base station.

[0127] By employing the terminal-executed method of the above-described embodiments of the present disclosure, when subcarrier-level precoding is applied, the feedback overhead related to precoding from the terminal to the base station can be reduced, thereby improving the performance of the communication system.

[0128] Below, in conjunction with Figure 4 This describes a method performed by a base station according to embodiments of the present disclosure. Figure 4 A flowchart of a method performed by a base station according to an embodiment of the present disclosure is shown. Since method 400 is the same as described above... Figure 2 The methods described in Method 200 are identical in some details; therefore, for the sake of simplicity, detailed descriptions of the same content have been omitted.

[0129] like Figure 4 As shown, in step S401, the base station determines a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for the precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system. In step S402, the base station determines a second parameter, wherein the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level. Then, in step S403, the base station sends first information indicating the first parameter and second information indicating the second parameter to the terminal in the communication system.

[0130] This disclosure reduces the number of candidate transform domain vectors for the subcarrier-level precoding matrix from the number of subcarriers (N3) in the communication system to the value of the first parameter by introducing a new parameter, namely the first parameter. Because the number of candidate transform domain vectors for the subcarrier-level precoding matrix is ​​reduced, the feedback overhead is correspondingly reduced in selecting the transform domain vectors from the candidate vectors to determine the subcarrier-level precoding matrix and in feeding the selected transform domain vectors back to the base station.

[0131] In this disclosure, when determining the value of the first parameter, the base station can utilize the channel characteristics of the multipath channel in the delay domain to achieve the technical effect of reducing feedback overhead. Specifically, the multipath channel exhibits the following characteristics in the delay domain: the average channel power associated with a given multipath delay decreases as the delay increases, and the channel power is mainly concentrated in the range of smaller delays. For subcarrier-level precoding and / or CSI feedback, such as precoding and / or CSI feedback based on the aforementioned eTDP, the above-mentioned channel characteristics can be used to reduce feedback overhead.

[0132] For example, in step S401, the base station can determine the value of the first parameter based on the channel delay spread. For example, when the channel delay spread is large, the base station can configure the value of the first parameter to be large; and when the channel delay spread is small, the base station can configure the value of the first parameter to be small. For example, when the channel delay spread is greater than a first threshold, the base station can configure the value of the first parameter to be large (e.g., 64); and when the channel delay spread is less than or equal to the first threshold, the base station can configure the value of the first parameter to be small (e.g., 16).

[0133] Furthermore, the candidate transform domain vector in step S401 can be a Discrete Fourier Transform (DFT) vector.

[0134] Furthermore, the first parameter in step S401 can be represented as M. max Its value is less than the number of subcarriers in the communication system (i.e., N3 mentioned above) and greater than the number of subbands in the communication system (e.g., it can be represented as N0). Alternatively, the value of the first parameter in step S401 can be less than the number of subcarriers (N3) in the communication system and less than or equal to the number of subbands (N0) in the communication system.

[0135] Furthermore, in this disclosure, the transform domain can be the domain after transforming the frequency domain, such as the delay domain. The candidate transform domain vector in step S401 can be a Discrete Fourier Transform (DFT) vector.

[0136] Furthermore, according to an example of this disclosure, in step S403, the first information used to indicate the first parameter may include the first parameter. For example, the first information may only include the first parameter, that is, the first information is the first parameter. As another example, the first information may include not only the first parameter, but also other information (e.g., other configuration information sent by the base station to the terminal).

[0137] Furthermore, according to an example of this disclosure, in step S403, the first information used to indicate the first parameter can also be used to indicate the value range of the first parameter. In this example, the terminal can determine the value range of the first parameter based on the first information, select a value from the value range, and use the selected value as the value of the first parameter.

[0138] Furthermore, in step S403, the base station may send the first information to the terminal via higher-layer signaling. In the example where the higher-layer signaling is RRC signaling or MAC CE, the base station may send the first information to the terminal via RRC signaling or MAC CE. Accordingly, the terminal may receive the first information from the base station via RRC signaling or MAC CE.

[0139] Alternatively, in step S403, the base station may send the first information to the terminal via lower-layer signaling. In the example where the lower-layer signaling is DCI, the base station may send the first information to the terminal via DCI. Accordingly, the terminal may receive the first information from the base station via DCI.

[0140] In this disclosure, the base station can notify the terminal not only of the number (M) of candidate transform domain vectors of the precoding matrix at the subcarrier level. max It can also notify the terminal of the number of transform domain vectors that the terminal should select from the candidate transform domain vectors (i.e., M mentioned above). v This allows the terminal to determine the precoding matrix indication information. Therefore, in step S402, the base station determines a second parameter, where the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level, and the value of the second parameter is less than the value of the first parameter; and in step S403, the base station sends second information to the terminal indicating the second parameter. As described above, the second parameter can be represented as M. v And it is a positive integer, where v represents the rank corresponding to the terminal and is a positive integer.

[0141] According to one example of this disclosure, the second information in step S403 can explicitly indicate a second parameter. For example, the second information may include the second parameter. In this example, the base station can send the second information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal can receive the second information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the second parameter. Alternatively, the base station can send the second information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal can receive the second information from the base station via lower-layer signaling such as DCI to obtain the second parameter.

[0142] According to another example of this disclosure, the second information in step S403 can implicitly indicate the second parameter. For example, the second information can be used to indicate a first factor corresponding to the value of the second parameter. The first factor can be represented as p v Its value is greater than zero and less than one, that is, 0 < p v <1. In this example, the base station determines the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level. max And the number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v After that, the base station can determine the relationship with M according to preset rules. v The corresponding first factor (p) v For example, the base station can determine the number of candidate transform domain vectors (M) based on the precoding matrix at the subcarrier level. max The number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v ), and formula (1) above, determine the relationship with M from the set of the first factors (hereinafter referred to as the first set). v The corresponding first factor (p) v ).

[0143] In this example, the base station can determine a first set based at least on the value of the rank corresponding to the terminal, the number of beams (e.g., spatial beams), and the first parameter, wherein the first set includes one or more first factors. Then, the base station can determine the first set based on the value of the first parameter (i.e., the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level). max The values ​​of the second parameter (i.e., the number of transform domain vectors the terminal should select from the candidate transform domain vectors (M)) and the second parameter are also important. v The base station determines a first factor corresponding to the value of the second parameter from the first set. Alternatively, the base station can determine the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level. max ) and the first factor (p v This eliminates the need to determine the number (M) of transform domain vectors the terminal should select from the candidate transform domain vectors. v For example, a base station can determine a first factor (p) from the set of first factors. v And notify the terminal.

[0144] Furthermore, when defining the first factor in the first set, multiple factors can be considered. For example, these multiple factors may include the first parameter, namely the number of candidate transform domain vectors (i.e., M as described above). maxThe values ​​of the first factor in the first set can be denoted as , and / or the rank (i.e., v mentioned above), and / or the number of beams (e.g., which can be represented as L). For example, in the example where the base station determines the first set based on the first parameter, when the value of the first parameter is greater than the second threshold, the value of the first factor in the first set can be smaller (e.g., the first set can be {1 / 8, 1 / 16, 1 / 32}); when the value of the first parameter is less than the second threshold, the value of the first factor in the first set can be larger (e.g., the first set can be {1 / 2, 1 / 4, 1 / 8}).

[0145] Furthermore, in this example, the base station can directly indicate the fifth parameter through the second information, and there is a correspondence between the values ​​of the fifth parameter and the values ​​of the first factor. Therefore, the base station can also indirectly indicate the first factor through the second information. Accordingly, the terminal can determine the value of the fifth parameter based on the second information, and determine the value of the first factor based on the determined value of the fifth parameter and the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor.

[0146] The fifth parameter described here can be paramCombination-rX as specified in wireless communication standard specifications (such as 3GPP standard specifications), where "rX" represents the version number of the communication system. For example, in the example of NR version 16 (R16) of the communication system, the fifth parameter could be paramCombination-r16.

[0147] According to an example of this disclosure, the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor can be pre-defined for use by the base station and the terminal. When setting the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor, various factors can be considered. For example, these factors may include the number of candidate transform domain vectors (i.e., M as described above). max The fifth parameter can also indicate the value of the rank (v mentioned above) and / or the number of beams (L mentioned above). Furthermore, the fifth parameter can also indicate the value of the second factor, which can be used to limit the number of coefficients, such as amplitude or phase, that the terminal feeds back to the base station to reduce feedback overhead. This second factor can be a factor specified in wireless communication standards (e.g., 3GPP standards), such as factor β specified in NR version 16 (R16). It should be recognized that when the wireless communication system does not support subcarrier-level precoding techniques, the factors considered when setting the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor may include the value of the rank (v mentioned above) and / or the number of beams (e.g., which can be represented as L).

[0148] For example, when the number of candidate transform domain vectors (i.e., M as described above) max When the number of candidate transform domain vectors (i.e., M as described above) is large, the value of the first factor can be relatively small. max When the rank (v) is small, the value of the first factor can be relatively large.

[0149] Table 1 below shows an example of the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor, taking into account the values ​​of the rank (i.e., v mentioned above) and the number of beams (i.e., L mentioned above), where the fifth parameter can be paramCombination-r16. Furthermore, Table 1 can also be referred to as the table for the number of beams (L), the second factor (β), and the first factor (p). v The codebook parameter configuration.

[0150]

[0151] Table 1 shows an example of the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor.

[0152] Table 2 below shows the number of candidate transform domain vectors (i.e., M as described above). max This is another example of the correspondence between the values ​​of the fifth parameter (i.e., v mentioned above), the rank (i.e., the number of beams mentioned above), and the values ​​of the first factor, where the fifth parameter can be paramCombination-rX. In the example in Table 2, the rank can be 1, 2, 3, or 4. Furthermore, Table 2 can also be referred to as a table for the number of beams (L), the second factor (β), and the first factor (p) with a rank less than or equal to 4. v The codebook parameter configuration.

[0153]

[0154] Another example of the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor in Table 2.

[0155] Table 3 below shows the number of candidate transform domain vectors (i.e., M as described above). maxThis is another example of the correspondence between the values ​​of the fifth parameter (v) and the values ​​of the first factor, which are set for the rank (v mentioned above) and the number of beams (L mentioned above), where the fifth parameter can be paramCombination-rX. In the example in Table 3, the rank can be 1, 2, 3, 4, 5, or 6. Furthermore, Table 3 can also be referred to as a table for the number of beams (L), the second factor (β), and the first factor (p) with a rank less than or equal to 6. v The codebook parameter configuration.

[0156]

[0157] Table 3 provides another example of the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor.

[0158] In this disclosure, when the value of the first parameter indicated by the first information is small, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level... max When the value is small, the terminal can directly access the M. max M is selected from the candidate transform domain vectors. v The number of candidate transform domain vectors. When the value of the first parameter indicated by the first information is large, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is large, the terminal can determine an intermediate subset (InS or subset) of candidate transform domain vectors and select M from this subset. v A transform domain vector is used to further reduce feedback overhead.

[0159] When the number of candidate transform domain vectors (i.e., M as described above) max M is larger and selected from a subset of candidate transform domain vectors. v When there are multiple transform domain vectors, the base station can determine the correspondence between the values ​​of the fifth parameter and the first factor using Table 1 described above. Furthermore, when the number of candidate transform domain vectors (i.e., M as described above) is... max Smaller and from M max M is selected from the candidate transform domain vectors. v When dealing with a transform domain vector, the base station can determine the correspondence between the value of the fifth parameter and the value of the first factor using Tables 2 and 3 described above.

[0160] The following is a schematic diagram of how the base station and terminal use the above table. For example, the rank is 4 (i.e., v = 4), and the number of candidate transform domain vectors for the precoding matrix at the subcarrier level is equal to 64 (i.e., M). max=64), the number of transform domain vectors used to determine the precoding matrix at the subcarrier level is equal to 8 (i.e., M). v =8), then the base station can determine the first factor equal to 1 / 8 (i.e., p) based on the above formula (1) and the first set. v =1 / 8). The base station can determine the value of the fifth parameter to be 6 (i.e., paramCombination-rX = 6) based on Table 3 above. Then, the base station can notify the terminal of the value of the fifth parameter. After the terminal learns that the value of the fifth parameter is 6, it can determine the value of the rank (i.e., v = 4) and the number of candidate transform domain vectors of the precoding matrix at the subcarrier level (i.e., M). max =64) and Table 3 above, to determine the corresponding first factor (i.e., p) v =1 / 8). Then, the terminal can determine the number of transform domain vectors (i.e., M) used to determine the precoding matrix of the subcarrier level according to the above formula (1). v =8).

[0161] It should be recognized that step S402 can be performed after step S401, or before step S401, or simultaneously with step S401. Figure 4 The diagram only shows the execution of step S402 after step S401. Examples of executing step S402 before step S401 and examples of executing steps S401 and S402 simultaneously are not shown.

[0162] Furthermore, for the subset (InS) of candidate transform domain vectors mentioned above, the terminal requires two more parameters when determining the subset (InS): a third parameter and a fourth parameter. The third parameter can be represented as N3. ’ Its value represents the number of vectors included in the subset (InS) of candidate transform domain vectors (also known as the size of the subset). If the number of vectors included in the subset (InS) of candidate transform domain vectors is greater than the number of transform domain vectors the terminal should select from the candidate transform domain vectors (M... v For example, it can be 2M. v In other words, N3 ’ It can be equal to 2M v Furthermore, the fourth parameter can be used to determine the subset of candidate transform domain vectors, which can be represented as M. initial The range of values ​​for the fourth parameter can be specified by wireless communication standards (e.g., 3GPP standards). For example, the range of values ​​for the fourth parameter can be related to the third parameter, such as M. initial ∈{-N3 ’ +1, -N3 ’ +2, ..., 0}.

[0163] The terminal and the base station can negotiate a third parameter (N3) in advance. ’ The value of ) and the fourth parameter (M) initial The values ​​of the third parameter and the fourth parameter are determined according to the first example of this disclosure. The terminal can determine the values ​​of the third parameter and the fourth parameter and report these values ​​to the base station. According to the second example of this disclosure, the base station can determine the values ​​of the third parameter and the fourth parameter and notify the terminal of these values. According to the third example of this disclosure, the terminal can determine the value of the third parameter and report it to the base station, and the base station can determine the value of the fourth parameter and notify the terminal of this value. According to the fourth example of this disclosure, the base station can determine the value of the third parameter and notify the terminal of this value, and the terminal can determine the value of the fourth parameter and report it to the base station.

[0164] The third parameter (N3) is determined at the base station. ’ The value of ) and the fourth parameter (M) initial In examples of the possible values ​​for ), wireless communication standards (e.g., 3GPP standards) may specify a third parameter (N3). ’ The base station can select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. Furthermore, the base station can notify the terminal of the selected value of the third parameter. The base station can select a value from the fourth parameter (M). initial The base station selects a value from the range of possible values ​​and uses the selected value as the value of the fourth parameter. Furthermore, the base station can notify the terminal of the selected value of the fourth parameter.

[0165] For example, the base station can use the third parameter (N3) to indicate the third parameter. ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth information is included in an indication message, which is then sent to the terminal. For example, the base station may send indication information to the terminal to indicate a subset of candidate transform domain vectors, so that the terminal can determine the number of transform domain vectors indicated by the second information from the subset. This indication information may include information indicating the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0166] For example, the base station can send instructions to the terminal to indicate the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0167] Specifically, the base station can send a signal to the terminal indicating a third parameter (N3). ’ The third information (e.g.) Figure 4 (Step S404 in the above steps). The third information may include a third parameter. Accordingly, the terminal can receive third information from the base station indicating the third parameter, and obtain the third parameter based on the third information, thereby determining the value of the third parameter. For example, the base station can send the third information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal can receive the third information from the base station via higher-layer signaling such as RRC or MAC CE, thereby obtaining the third parameter and determining the value of the third parameter. Alternatively, the base station can send the third information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal can receive the third information from the base station via lower-layer signaling such as DCI, thereby obtaining the third parameter and determining the value of the third parameter.

[0168] The base station can be determined from the fourth parameter (M) initial The base station selects a value from the range of possible values ​​and uses the selected value as the value of the fourth parameter. Furthermore, the base station can notify the terminal of the selected value of the fourth parameter.

[0169] For example, the base station can send a signal to the terminal to indicate the fourth parameter (M). initial The fourth piece of information (e.g., Figure 4 (Step S405 in the above steps). The fourth information may include a fourth parameter. Accordingly, the terminal can receive the fourth information from the base station indicating the fourth parameter, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter. For example, the base station can send the fourth information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal can receive the fourth information from the base station via higher-layer signaling such as RRC or MAC CE, thereby obtaining the fourth parameter and determining the value of the fourth parameter. Alternatively, the base station can send the fourth information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal can receive the fourth information from the base station via lower-layer signaling such as DCI, thereby obtaining the fourth parameter and determining the value of the fourth parameter.

[0170] Continue to refer to Figure 4 Following step S405, method 400 may further include steps S406 and S407. In step S406, the base station can receive precoding matrix indication information from the terminal. Then, in step S407, the base station can generate a precoding matrix based on the precoding matrix indication information. In this disclosure, the precoding matrix indication information may be a PMI (Precoding Indication Machine). The base station can generate the precoding matrix according to conventional methods for generating precoding matrices via PMI (e.g., methods specified in 3GPP standards).

[0171] Furthermore, in this disclosure, the precoding matrix indication information can be subcarrier-level precoding matrix indication information (e.g., subcarrier-level PMI) rather than subband-level precoding matrix indication information (e.g., subband-level PMI). Additionally, the "candidate transform domain vector for subcarrier-level precoding matrix" described above can be a candidate transform domain vector for subcarrier-level precoding matrix indication information (e.g., subcarrier-level PMI). The "transform domain vector for determining the subcarrier-level precoding matrix" described above can be a transform domain vector for determining the subcarrier-level precoding matrix indication information (e.g., subcarrier-level PMI).

[0172] By employing the method executed by the base station according to the above embodiments of the present disclosure, when subcarrier-level precoding is applied, the feedback overhead related to precoding from the terminal to the base station can be reduced, thereby improving the performance of the communication system.

[0173] Below, refer to Figure 5 To describe a terminal according to an embodiment of this disclosure. Figure 5 This is a structural schematic diagram of a terminal 500 according to an embodiment of the present disclosure. The functions of the terminal 500 are the same as those described above. Figure 2 The methods described in method 200 share some details, therefore, for simplicity, detailed descriptions of the same content are omitted. For example... Figure 5 As shown, terminal 500 includes: a receiving unit 510 configured to receive first information from a base station in the communication system for indicating a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for a precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system; the receiving unit 510 is further configured to receive second information from the base station for indicating a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level; and a control unit 520 configured to determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information. In addition to these two units, terminal 500 may also include other components; however, since these components are not relevant to the content of this disclosure embodiment, their illustrations and descriptions are omitted here.

[0174] According to one example of this disclosure, a base station can send first information to a terminal via higher-layer signaling. In examples where the higher-layer signaling is Radio Resource Control (RRC) signaling or Media Access Control (MAC) Control Element (CE), the base station can send the first information to the terminal via RRC signaling or MAC CE. Accordingly, the receiving unit 510 can receive the first information from the base station via RRC signaling or MAC CE.

[0175] Furthermore, the base station can send the first information to the terminal via lower-layer signaling. In the example where the lower-layer signaling is downlink control information (DCI), the base station can send the first information to the terminal via DCI. Accordingly, the receiving unit 510 can receive the first information from the base station via DCI.

[0176] In this disclosure, the base station can notify the terminal not only of the number (M) of candidate transform domain vectors of the precoding matrix at the subcarrier level. max Furthermore, it can notify the terminal of the number of transform domain vectors it should select from the candidate transform domain vectors, so that the terminal can determine the precoding matrix indication information. Therefore, the receiving unit 510 receives second information from the base station for indicating the second parameter, wherein the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level, and the value of the second parameter is less than the value of the first parameter. The second parameter can be represented as M. v And it is a positive integer, where v represents the rank corresponding to the terminal and is a positive integer.

[0177] Furthermore, according to one example of this disclosure, the second information may explicitly indicate the second parameter. For example, the second information may include the second parameter. In this example, the base station may send the second information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the receiving unit 510 may receive the second information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the second parameter. Alternatively, the base station may send the second information to the terminal via lower-layer signaling such as DCI. Accordingly, the receiving unit 510 may receive the second information from the base station via lower-layer signaling such as DCI to obtain the second parameter.

[0178] According to another example of this disclosure, the second information can implicitly indicate a second parameter. For example, the second information can be used to indicate a first factor corresponding to the value of the second parameter. The first factor can be represented as p. v Its value is greater than zero and less than one, that is, 0 < p v<1. In this example, the base station determines the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level. max And the number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v After that, the base station can determine the relationship with M according to preset rules. v The corresponding first factor (p) v For example, the base station can determine the number of candidate transform domain vectors (M) based on the precoding matrix at the subcarrier level. max The number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v ), and formula (1) above, determine the relationship with M from the set of first factors. v The corresponding first factor (p) v ).

[0179] Furthermore, in determining the precoding matrix, in addition to the transform domain vector, multiple spatial domain vectors (also called spatial beams, spatial codewords, wideband codewords, or wideband spatial codewords, etc.) are needed, for example, L spatial domain vectors, where L is a positive integer. Each spatial domain vector has frequency domain weighting coefficients. The transform domain vectors in this disclosure can be used to transform and compress the frequency domain weighting coefficients of the spatial domain vectors (e.g., first transforming them to the delay domain, and then compressing them in that delay domain). However, since the spatial domain vectors are not related to the technical solutions of this disclosure, the descriptions related to the spatial domain vectors are omitted in this disclosure.

[0180] Furthermore, the control unit 520 can determine the value of the second parameter based on the first factor and the first parameter. Specifically, the control unit 520 can determine the value of the second parameter based on the value of the first factor and the value of the first parameter. For example, the control unit 520 can determine the value of the second parameter using the formula (1) described above.

[0181] Furthermore, the control unit 520 can determine the precoding matrix indication information based at least on the first information and the second information. For example, the control unit 520 can determine the precoding matrix indication information based at least on the first parameter indicated by the first information and the second parameter indicated by the second information.

[0182] Alternatively, the control unit 520 can select the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information, so that the control unit 520 can determine the precoding matrix indication information at least based on the selected transform domain vectors. That is, the control unit 520 can select the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information, so that the control unit 520 can determine the precoding matrix indication information based on the M information of the subcarrier-level precoding matrix. max M is selected from the candidate transform domain vectors. v Transformation domain vectors, and at least according to the chosen M vA transform domain vector is used to determine the precoding matrix indication information.

[0183] When the value of the first parameter indicated by the first information is small, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is small, the terminal can directly access the M. max M is selected from the candidate transform domain vectors. v The number of candidate transform domain vectors. When the value of the first parameter indicated by the first information is large, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is large, the control unit 520 can determine the intermediate subset (InS or subset) of the candidate transform domain vectors, and select M from this subset. v M transform domain vectors are used to further reduce feedback overhead. For example, receiving unit 510 can receive indication information from the base station indicating a subset of the candidate transform domain vectors, and control unit 520 can determine the number of transform domain vectors indicated by the second information from the subset (i.e., select M from the subset). v (a transform domain vector).

[0184] According to an example of this disclosure, when determining a subset (InS) of candidate transform domain vectors, the control unit 520 requires two more parameters, a third parameter and a fourth parameter. The third parameter can be represented as N3. ’ Its value represents the number of vectors included in the subset (InS) of candidate transform domain vectors (also known as the size of the subset). If the number of vectors included in the subset (InS) of candidate transform domain vectors is greater than the number of transform domain vectors the terminal should select from the candidate transform domain vectors (M... v For example, it can be 2M. v In other words, N3 ’ It can be equal to 2M v Furthermore, the fourth parameter can be used to determine the subset of candidate transform domain vectors, which can be represented as M. initial The range of values ​​for the fourth parameter can be specified by wireless communication standards (e.g., 3GPP standards). For example, the range of values ​​for the fourth parameter can be related to the third parameter, such as M. initial ∈{-N3 ’ +1, -N3 ’ +2, ..., 0}.

[0185] The terminal and the base station can negotiate a third parameter (N3) in advance. ’ The value of ) and the fourth parameter (M) initialThe terminal can determine the values ​​of the third parameter and the fourth parameter according to a first example of this disclosure, and report the determined values ​​of the third parameter and the fourth parameter to the base station. According to a second example of this disclosure, the base station can determine the values ​​of the third parameter and the fourth parameter, and notify the terminal of the determined values ​​of the third parameter and the fourth parameter. According to a third example of this disclosure, the terminal can determine the value of the third parameter and report the determined value of the third parameter to the base station, and the base station can determine the value of the fourth parameter and notify the terminal of the determined value of the fourth parameter. According to a fourth example of this disclosure, the base station can determine the value of the third parameter and notify the terminal of the determined value of the third parameter, and the terminal can determine the value of the fourth parameter and report the determined value of the fourth parameter to the base station. In these examples, the terminal may further include a transmitting unit 530.

[0186] Determine the third parameter (N3) at the terminal. ’ The value of ) and the fourth parameter (M) initial In the first example of the value of the third parameter, the wireless communication standard specification (e.g., the 3GPP standard specification) can define the range of values ​​for the third parameter. The terminal's control unit 520 can select a value from this range and use the selected value as the value of the third parameter. Furthermore, the terminal's transmitting unit 530 can report the selected value of the third parameter to the base station. For example, the terminal's transmitting unit 530 can include the value of the third parameter as part of the PMI and feed the PMI back to the base station, thereby enabling the terminal to report the value of the third parameter to the base station. Similarly, the terminal's control unit 520 can select a value from the range of values ​​for the fourth parameter and use the selected value as the value of the fourth parameter. Furthermore, the terminal's transmitting unit 530 can report the selected value of the fourth parameter to the base station. For example, the terminal's transmitting unit 530 can include the value of the fourth parameter as part of the PMI and feed the PMI back to the base station, thereby enabling the terminal to report the value of the fourth parameter to the base station.

[0187] Furthermore, the base station determines the third parameter (N3) ’ The value of ) and the fourth parameter (M) initial In the second example of the value of ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’ The base station can select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. The base station can notify the terminal of the selected value of the third parameter. Additionally, the base station can select a value from the fourth parameter (M). initialThe base station selects a value from the range of possible values ​​and uses the selected value as the value of the fourth parameter. The base station can then notify the terminal of the selected value of the fourth parameter.

[0188] For example, the base station can use the third parameter (N3) to indicate the third parameter. ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth information is included in an indication message, which is then sent to the terminal. For example, the base station may send indication information to the terminal to indicate a subset of candidate transform domain vectors, so that the terminal can determine the number of transform domain vectors indicated by the second information from the subset. This indication information may include information indicating the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth information may include a third parameter. Accordingly, the receiving unit 510 may receive indication information from the base station for indicating a subset of candidate transform domain vectors, and determine from the subset the number of transform domain vectors indicated by the second information.

[0189] For example, the base station can send instructions to the terminal to indicate the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0190] Specifically, the base station can send a signal to the terminal indicating a third parameter (N3). ’ The receiving unit 510 can receive third information from the base station to indicate the third parameter, and obtain the third parameter based on the third information, thereby determining the value of the third parameter.

[0191] In addition, the base station can send a fourth parameter (M) to the terminal. initial The fourth information may include a fourth parameter. Accordingly, the receiving unit 510 can receive the fourth information indicating the fourth parameter from the base station, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter.

[0192] In addition, the third parameter (N3) is determined at the terminal. ’ The value of ) and the base station determines the fourth parameter (M) initial In the third example of the value of ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’The terminal's control unit 520 can select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. Furthermore, the terminal's transmission unit 530 can report the selected value of the third parameter to the base station. For example, the terminal's transmission unit 530 can use the value of the third parameter as part of the PMI and feed the PMI back to the base station, thereby enabling the terminal to report the value of the third parameter to the base station. Additionally, the base station can select a value from the range of values ​​for the fourth parameter (M). initial The base station selects a value from the range of possible values ​​for the fourth parameter and uses the selected value as the value of the fourth parameter. The base station can notify the terminal of the selected value of the fourth parameter. For example, the base station can send fourth information indicating the fourth parameter to the terminal via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI. The fourth information may include the fourth parameter. Accordingly, the terminal's receiving unit 510 can receive the fourth information indicating the fourth parameter from the base station via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter.

[0193] Furthermore, the base station determines the third parameter (N3) ’ The value of ) and the terminal determines the fourth parameter (M) initial In the fourth example of the possible values ​​for ), wireless communication standard specifications (e.g., 3GPP standard specifications) may specify a third parameter (N3). ’ The base station can select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. The base station can notify the terminal of the selected value of the third parameter. For example, the base station can send third information indicating the third parameter to the terminal via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI, and the third information may include the third parameter. Accordingly, the terminal's receiving unit 510 can receive the third information indicating the third parameter from the base station via higher-layer signaling such as RRC or MAC CE or lower-layer signaling such as DCI, and obtain the third parameter based on the third information, thereby determining the value of the third parameter. In addition, the terminal's control unit 520 can select a value from the range of values ​​for the fourth parameter and use the selected value as the value of the fourth parameter. In addition, the terminal's transmitting unit 530 can report the selected value of the fourth parameter to the base station. For example, the terminal's transmitting unit 530 can use the value of the fourth parameter as part of the PMI and feed the PMI back to the base station, thereby realizing that the terminal reports the value of the fourth parameter to the base station.

[0194] The third parameter (N3) was obtained in the control unit 520. ’ ) and the fourth parameter (M) initialThen, the control unit 520 can determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information based on the third parameter and the fourth parameter.

[0195] For example, firstly, the control unit 520 can generate a subset (InS) of candidate transform domain vectors from the number of candidate transform domain vectors indicated by the first information, based on the third parameter and the fourth parameter. For example, the terminal can generate the subset (InS) of candidate transform domain vectors according to formula (2) above. Then, the control unit 520 can determine the number of transform domain vectors indicated by the second information from this subset (InS). For example, the terminal can select M from this subset (InS). v Transformed domain vectors.

[0196] Furthermore, the control unit 520 can determine the precoding matrix indication information based on the determined transform domain vectors. That is, the terminal selects the number of transform domain vectors indicated by the second information (i.e., selects M). v After the number of transform domain vectors, the terminal can determine the precoding matrix indication information based on the number of transform domain vectors indicated by the selected second information.

[0197] In this disclosure, the precoding matrix indication information can be a PMI. The terminal can generate the PMI according to a conventional method of determining the PMI based on transform domain basis vectors (e.g., the method specified in 3GPP standards). For example, the precoding matrix indication information may include M... v The index of a transform domain vector, or the M v Quantization information of the indices of the transform domain vectors.

[0198] Furthermore, the transmitting unit 530 can send precoding matrix indication information to the base station. In the example where the precoding matrix indication information is PMI, the terminal can include the PMI in the CSI report and send the CSI report to the base station, thereby realizing the feedback of PMI to the base station.

[0199] By using the terminal described in the above-described embodiments of the present disclosure, when subcarrier-level precoding is applied, the feedback overhead related to precoding from the terminal to the base station can be reduced, thereby improving the performance of the communication system.

[0200] Below, refer to Figure 6 To describe a base station according to an embodiment of this disclosure. Figure 6 This is a schematic diagram of the structure of a base station 600 according to an embodiment of this disclosure. The function of the base station 600 is the same as that described above. Figure 4 The methods described in 400 share some details, therefore, for simplicity, detailed descriptions of the same content are omitted. For example... Figure 6As shown, base station 600 includes: a control unit 610 configured to determine a first parameter, wherein the first parameter represents the number of candidate transform domain vectors for a precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system; the control unit 610 is further configured to determine a second parameter, wherein the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level; and a transmission unit 620 configured to transmit first information indicating the first parameter and second information indicating the second parameter to a terminal in the communication system. Besides these two units, base station 600 may also include other components; however, since these components are not relevant to the content of this disclosure embodiment, their illustrations and descriptions are omitted here.

[0201] In this disclosure, the base station can utilize the channel characteristics of the multipath channel in the delay domain when determining the value of the first parameter to achieve the technical effect of reducing feedback overhead. Specifically, the multipath channel exhibits the following characteristics in the delay domain: the average channel power associated with a given multipath delay decreases as the delay increases, and the channel power is mainly concentrated in the range of smaller delays. For subcarrier-level precoding and / or CSI feedback, such as precoding and / or CSI feedback based on the aforementioned eTDP, the above-mentioned channel characteristics can be used to reduce feedback overhead.

[0202] For example, the control unit 610 can determine the value of the first parameter based on the channel delay spread. For example, when the channel delay spread is large, the control unit 610 can configure the value of the first parameter to be large; and when the channel delay spread is small, the control unit 610 can configure the value of the first parameter to be small.

[0203] Furthermore, the sending unit 620 can send the first information to the terminal via higher-layer signaling. In an example where the higher-layer signaling is RRC signaling or MAC CE, the sending unit 620 can send the first information to the terminal via RRC signaling or MAC CE. Accordingly, the terminal can receive the first information from the base station via RRC signaling or MAC CE. Alternatively, the sending unit 620 can send the first information to the terminal via lower-layer signaling. In an example where the lower-layer signaling is DCI, the sending unit 620 can send the first information to the terminal via DCI. Accordingly, the terminal can receive the first information from the base station via DCI.

[0204] In this disclosure, the base station can notify the terminal not only of the number (M) of candidate transform domain vectors of the precoding matrix at the subcarrier level. max It can also notify the terminal of the number of transform domain vectors that the terminal should select from the candidate transform domain vectors (i.e., M mentioned above). vThis allows the terminal to determine the precoding matrix indication information. Therefore, the control unit 610 determines a second parameter, where the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level, and the value of the second parameter is less than the value of the first parameter; and the transmitting unit 620 transmits second information indicating the second parameter to the terminal. As described above, the second parameter can be represented as M. v And it is a positive integer, where v represents the rank corresponding to the terminal and is a positive integer.

[0205] According to one example of this disclosure, the second information may explicitly indicate a second parameter. For example, the second information may include the second parameter. In this example, the transmitting unit 620 may transmit the second information to the terminal via higher-layer signaling such as RRC or MAC CE. Accordingly, the terminal may receive the second information from the base station via higher-layer signaling such as RRC or MAC CE to obtain the second parameter. Alternatively, the transmitting unit 620 may transmit the second information to the terminal via lower-layer signaling such as DCI. Accordingly, the terminal may receive the second information from the base station via lower-layer signaling such as DCI to obtain the second parameter.

[0206] According to another example of this disclosure, the second information can implicitly indicate a second parameter. For example, the second information can be used to indicate a first factor corresponding to the value of the second parameter. The first factor can be represented as p. v Its value is greater than zero and less than one, that is, 0 < p v <1. In this example, the number (M) of candidate transform domain vectors for the precoding matrix at the subcarrier level is determined in the control unit 610. max And the number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v After that, the control unit 610 can determine the relationship with M according to preset rules. v The corresponding first factor (p) v For example, the control unit 610 can determine the number of candidate transform domain vectors (M) based on the precoding matrix at the subcarrier level. max The number of transform domain vectors (M) that the terminal should select from the candidate transform domain vectors. v ), and formula (1) above, determine the relationship with M from the set of the first factors (hereinafter referred to as the first set). v The corresponding first factor (p) v ).

[0207] In this example, the control unit 610 can determine a first set based at least on the value of the rank corresponding to the terminal, the number of beams (e.g., spatial beams), and the first parameter, wherein the first set includes one or more first factors. Then, the control unit 610 can determine the first set based on the value of the first parameter (i.e., the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level). max The values ​​of the second parameter (i.e., the number of transform domain vectors the terminal should select from the candidate transform domain vectors (M)) and the second parameter are also important. v )), determine the first factor corresponding to the value of the second parameter from the first set.

[0208] Furthermore, when defining the first factor in the first set, multiple factors can be considered. For example, these multiple factors may include the first parameter, namely the number of candidate transform domain vectors (i.e., M as described above). max ), and / or the value of the rank (i.e., v mentioned above), and / or the number of beams (e.g., which can be represented as L), etc.

[0209] Furthermore, in this example, the control unit 610 can directly indicate the fifth parameter through the second information, and there is a correspondence between the values ​​of the fifth parameter and the values ​​of the first factor. Therefore, the control unit 610 can also indirectly indicate the first factor through the second information. Accordingly, the terminal can determine the value of the fifth parameter based on the second information, and determine the value of the first factor based on the determined value of the fifth parameter and the correspondence between the values ​​of the fifth parameter and the values ​​of the first factor.

[0210] In this disclosure, when the value of the first parameter indicated by the first information is small, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level... max When the value is small, the terminal can directly access the M. max M is selected from the candidate transform domain vectors. v The number of candidate transform domain vectors. When the value of the first parameter indicated by the first information is large, that is, the number of candidate transform domain vectors (M) of the precoding matrix at the subcarrier level. max When the value is large, the terminal can determine an intermediate subset (InS or subset) of candidate transform domain vectors and select M from this subset. v A transform domain vector is used to further reduce feedback overhead.

[0211] When the number of candidate transform domain vectors (i.e., M as described above) max M is larger and selected from a subset of candidate transform domain vectors. vWhen there are multiple transform domain vectors, the control unit 610 can determine the correspondence between the value of the fifth parameter and the value of the first factor using Table 1 described above. Furthermore, when the number of candidate transform domain vectors (i.e., M as described above) is... max Smaller and from M max M is selected from the candidate transform domain vectors. v When there is a transform domain vector, the control unit 610 can determine the correspondence between the value of the fifth parameter and the value of the first factor through Tables 2 and 3 described above.

[0212] In addition, for the subset (InS) of candidate transform domain vectors mentioned above, the terminal also needs two parameters when determining the subset (InS) of candidate transform domain vectors, namely the third parameter and the fourth parameter.

[0213] The terminal and the base station can negotiate a third parameter (N3) in advance. ’ The value of ) and the fourth parameter (M) initial The values ​​of the third parameter and the fourth parameter are determined according to the first example of this disclosure. The terminal can determine the values ​​of the third parameter and the fourth parameter and report these values ​​to the base station. According to the second example of this disclosure, the base station can determine the values ​​of the third parameter and the fourth parameter and notify the terminal of these values. According to the third example of this disclosure, the terminal can determine the value of the third parameter and report it to the base station, and the base station can determine the value of the fourth parameter and notify the terminal of this value. According to the fourth example of this disclosure, the base station can determine the value of the third parameter and notify the terminal of this value, and the terminal can determine the value of the fourth parameter and report it to the base station.

[0214] Determining the third parameter (N3) at the base station ’ The value of ) and the fourth parameter (M) initial In examples of the possible values ​​for ), wireless communication standards (e.g., 3GPP standards) may specify a third parameter (N3). ’ The control unit 610 can select a value from the range of values ​​for the third parameter and use the selected value as the value of the third parameter. Furthermore, the sending unit 620 can notify the terminal of the selected value of the third parameter. The control unit 610 can select a value from the range of values ​​for the fourth parameter (M). initial The system selects a value from the range of possible values ​​for the fourth parameter and uses the selected value as the value of the fourth parameter. Furthermore, the sending unit 620 can notify the terminal of the selected value of the fourth parameter.

[0215] For example, the transmitting unit 620 can be used to indicate the third parameter (N3) ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth information is included in an indication message, which is then sent to the terminal. For example, the sending unit 620 may send indication information to the terminal for indicating a subset of candidate transform domain vectors, so that the terminal can determine the number of transform domain vectors indicated by the second information from the subset. This indication information may include information for indicating the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0216] For example, the transmitting unit 620 can send signals to the terminal to indicate the third parameter (N3). ’ The third information and the information used to indicate the fourth parameter (M) initial The fourth piece of information.

[0217] Specifically, the sending unit 620 can send to the terminal a signal indicating the third parameter (N3). ’ The third information may include a third parameter. Accordingly, the terminal can receive third information from the base station indicating the third parameter, and obtain the third parameter based on the third information, thereby determining the value of the third parameter. Furthermore, the transmitting unit 620 can send information to the terminal indicating a fourth parameter (M). initial The fourth information may include a fourth parameter. Accordingly, the terminal can receive the fourth information from the base station to indicate the fourth parameter, and obtain the fourth parameter based on the fourth information, thereby determining the value of the fourth parameter.

[0218] Furthermore, base station 600 may also include receiving unit 630. Receiving unit 630 can receive precoding matrix indication information from the terminal. Control unit 610 can generate a precoding matrix based on the precoding matrix indication information. In this disclosure, the precoding matrix indication information may be a PMI (Precoding Indication Machine). The base station can generate the precoding matrix according to conventional methods for generating precoding matrices via PMI (e.g., methods specified in 3GPP standards).

[0219] By using the base station of the above-described embodiments of the present disclosure, when applying subcarrier-level precoding, the feedback overhead related to precoding from the terminal to the base station can be reduced, thereby improving the performance of the communication system.

[0220] It should be noted that the above embodiments of this disclosure are based on subcarrier-level precoding and / or CSI feedback techniques, rather than subband-level precoding and / or CSI feedback techniques. When a wireless communication system supports subband-level precoding techniques, the above embodiments of this disclosure can be applied in that wireless communication system. When a wireless communication system only supports subband-level precoding and CSI feedback techniques and does not support subcarrier-level precoding and / or CSI feedback techniques, the above embodiments of this disclosure cannot be applied in that wireless communication system. For example, the first parameter (M) in the above embodiments of this disclosure... max The second parameter (M) can be ignored and can be determined in accordance with the manner defined in NR version 16 (R16) as specified in wireless communication standard specifications (such as 3GPP standard specifications). v ) and the fourth parameter (M) initial ).

[0221] Furthermore, according to another embodiment of this disclosure, the terminal can report a rank value for the terminal to the base station, where the rank value can be a positive integer greater than or equal to four. For example, the base station can send constraint information (e.g., rank constraint information) to the terminal, indicating whether the base station allows the terminal to send information related to certain values ​​of the rank (e.g., PMI and / or Rank Indicator (RI)), where these values ​​can be positive integers greater than or equal to four. After receiving the constraint information, the terminal can send response information to the base station, indicating the rank value for the terminal, where the rank value can be a positive integer greater than or equal to four.

[0222] In this example, the constraint information can be typeII-RI-Restriction-rX as specified in the wireless communication standard specification (e.g., the 3GPP standard specification), where "rX" represents the version number of the communication system. For example, in an example where the version number of the communication system is NR version 17 (R17), this parameter could be typeII-RI-Restriction-r17.

[0223] Furthermore, according to an example of this disclosure, the data type and bit depth of typeII-RI-Restriction-rX can be defined as follows:

[0224] `typeII-RI-Restriction-rX BIT STRING(SIZE(n))`, where `n` represents the maximum number of data streams that the terminal can support transmitting simultaneously, and its value can be related to the maximum value of the rank (e.g., equal). For example, when the maximum rank for the terminal is 4, the value of `n` can be 4. Accordingly, the data type and bit width of `typeII-RI-Restriction-rX` can be defined as follows:

[0225] typeII-RI-Restriction-rX BIT STRING(SIZE(4)).

[0226] For example, when the maximum rank for a terminal is 6, the value of n can be 6. Correspondingly, the data type and bit depth of typeII-RI-Restriction-rX can be defined as follows:

[0227] typeII-RI-Restriction-rX BIT STRING(SIZE(6)).

[0228] Furthermore, in this example, the response information can be rank indication information, such as a rank indicator (RI). In an example where the response information is an RI, the terminal can include the RI in the CSI report and send the CSI report to the base station, thereby reporting the rank value used by the terminal to the base station.

[0229] Furthermore, the terminal 500 and base station 600 described above can be used to implement this other embodiment. For example, the transmitting unit 620 of the base station 600 can send constraint information (e.g., typeII-RI-Restriction-rX) to the terminal 500. This constraint information is used to indicate whether the base station 600 allows the terminal 500 to send information related to certain values ​​of the rank (e.g., PMI and / or Rank Indicator (RI)), which can be positive integers greater than or equal to four. The receiving unit 510 of the terminal 500 receives the constraint information, and the transmitting unit 530 of the terminal 500 can send response information (e.g., RI) to the base station, which indicates the rank value for the terminal, which can be a positive integer greater than or equal to four. In this way, when the rank value for the terminal is greater than or equal to four, the terminal can report the rank value for the terminal to the base station.

[0230] <Hardware Structure>

[0231] Furthermore, the block diagrams used in the above description of the embodiments illustrate blocks based on function. These functional blocks (structural units) are implemented through any combination of hardware and / or software. Moreover, the means of implementing each functional block are not particularly limited. That is, each functional block can be implemented using a single device that is physically and / or logically combined, or it can be implemented using multiple devices by directly and / or indirectly (e.g., via wired and / or wireless) connecting two or more physically and / or logically separate devices.

[0232] For example, the communication device (such as terminal 500, base station 600) of this disclosure embodiment can function as a computer that performs the processing of the wireless communication method of this disclosure. Figure 7 This is a schematic diagram of the hardware structure of a communication device 700 (terminal or base station) according to an embodiment of the present disclosure. The communication device 700 described above can be configured as a computer device that physically includes a processor 710, a memory 720, a storage device 730, a communication device 740, an input device 750, an output device 760, a bus 770, etc.

[0233] Additionally, in the following description, the word "device" can be replaced with circuit, equipment, unit, etc. The hardware structure of the user terminal and base station may include one or more of the devices shown in the figures, or may not include some of the devices.

[0234] For example, only one processor 710 is shown, but there can also be multiple processors. Furthermore, processing can be performed by a single processor, or by more than one processor simultaneously, sequentially, or using other methods. Additionally, processor 710 can be mounted on more than one chip.

[0235] The functions of device 700 are implemented, for example, by reading the specified software (program) into hardware such as processor 710 and memory 720, thereby enabling processor 710 to perform calculations, control the communication performed by communication device 740, and control the reading and / or writing of data in memory 720 and storage 730.

[0236] The processor 710, for example, enables the operating system to operate, thereby controlling the computer as a whole. The processor 710 may be composed of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, etc. For example, the aforementioned control unit can be implemented using the processor 710.

[0237] Furthermore, the processor 710 reads programs (program code), software modules, data, etc., from the memory 730 and / or communication device 740 into the memory 720, and performs various processes accordingly. As a program, a program that causes the computer to perform at least a portion of the actions described in the above embodiments can be employed. For example, the control unit of the terminal 500 can be implemented using a control program stored in the memory 720 and operated by the processor 710; similarly, other functional blocks can be implemented.

[0238] Memory 720 is a computer-readable recording medium, and may be constituted by at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Programmable ROM (EEPROM), Random Access Memory (RAM), or other suitable storage media. Memory 720 may also be referred to as a register, cache, main memory (main storage device), etc. Memory 720 may store executable programs (program code), software modules, etc., for implementing the methods involved in one embodiment of this disclosure.

[0239] The memory 730 is a computer-readable recording medium, and may be constituted by at least one of the following: a flexible disk, a floppy disk, a magneto-optical disk (e.g., a CD-ROM (Compact Disc ROM), a Digital Universal Optical Disc, a Blu-ray disc), a removable disk, a hard disk, a smart card, a flash memory device (e.g., a card, a stick, a key driver), a magnetic stripe, a database, a server, or other suitable storage media. The memory 730 may also be referred to as an auxiliary storage device.

[0240] The communication device 740 is hardware (transmitting and receiving device) used for communication between computers via wired and / or wireless networks, and is also referred to as a network device, network controller, network interface card (NIC), communication module, etc. To implement, for example, frequency division duplex (FDD) and / or time division duplex (TDD), the communication device 740 may include high-frequency switches, duplexers, filters, frequency synthesizers, etc. For example, the transmitting unit and receiving unit of the aforementioned terminal 500 can be implemented using the communication device 740.

[0241] Input device 750 is an input device that accepts input from external sources (e.g., keyboard, mouse, microphone, switch, button, sensor, etc.). Output device 760 is an output device that performs output to external sources (e.g., display, speaker, light-emitting diode (LED) lamp, etc.). Alternatively, input device 750 and output device 760 can also be integrated into a single structure (e.g., a touch panel).

[0242] Furthermore, the processor 710, memory 720, and other devices are connected via a bus 770 for communication. The bus 770 can consist of a single bus or different buses between devices.

[0243] Furthermore, base stations and terminals may include hardware such as microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic devices (PLDs), and field-programmable gate arrays (FPGAs), which can be used to implement some or all of the functional blocks. For example, processor 710 can be installed using at least one of these hardware components.

[0244] (Modified Example)

[0245] Furthermore, the terms used in this specification and / or those necessary for understanding this specification may be used interchangeably with terms that have the same or similar meanings. For example, a channel and / or symbol may also be a signal (signaling). Additionally, a signal may also be a message. A reference signal may also be simply referred to as RS (Reference Signal), and depending on the applicable standard, may also be called a pilot, pilot signal, etc. Furthermore, a component carrier (CC) may also be referred to as a cell, frequency carrier, carrier frequency, etc.

[0246] Furthermore, the information and parameters described in this specification can be expressed in absolute values, relative values ​​to specified values, or other corresponding information. For example, wireless resources can be indicated by a specified index. Moreover, the formulas used to apply these parameters may differ from those explicitly disclosed in this specification.

[0247] The names used for parameters, etc., in this specification are not limiting in any way. For example, various channels (Physical Uplink Control Channel (PUCCH), Physical Downlink Control Channel (PDCCH), etc.) and information elements can be identified by any appropriate name, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0248] The information, signals, etc., described in this specification can be represented using any of a wide variety of different technologies. For example, data, commands, instructions, information, signals, bits, symbols, chips, etc., that may be mentioned in all of the above descriptions can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0249] Furthermore, information and signals can be output from upper layers to lower layers and / or from lower layers to upper layers. Information and signals can be input or output via multiple network nodes.

[0250] Input or output information and signals can be stored in a specific location (such as memory) or managed through a management table. Input or output information and signals can be overwritten, updated, or supplemented. Output information and signals can be deleted. Input information and signals can be sent to other devices.

[0251] The notification of information is not limited to the methods / implementations described in this specification, and may also be carried out by other methods. For example, the notification of information may be implemented by physical layer signaling (e.g., downlink control information (DCI), uplink control information (UCI)), upper layer signaling (e.g., radio resource control (RRC) signaling, broadcast information (master information block (MIB), system information block (SIB) etc.), medium access control (MAC) signaling), other signals, or combinations thereof.

[0252] In addition, physical layer signaling can also be referred to as L1 / L2 (Layer 1 / Layer 2) control information (L1 / L2 control signals), L1 control information (L1 control signals), etc. Furthermore, RRC signaling can also be referred to as RRC messages, such as RRC connection setup messages, RRC connection reconfiguration messages, etc. Additionally, MAC signaling can be communicated, for example, through a MAC control unit (MAC CE (Control Element)).

[0253] Furthermore, notification of specified information (e.g., notification of “for X”) is not limited to being made explicitly, but can also be made implicitly (e.g., by not making notification of the specified information, or by notifying other information).

[0254] The determination can be made by a value represented by 1 bit (0 or 1), by a true or false Boolean value, or by a numerical comparison (e.g., a comparison with a specified value).

[0255] Whether it is called software, firmware, middleware, microcode, hardware description language, or any other name, software should be broadly interpreted as commands, command sets, code, code segments, program code, programs, subroutines, software modules, application programs, software applications, software packages, routines, subroutines, objects, executable files, execution threads, steps, functions, etc.

[0256] Furthermore, software, commands, information, etc., can be sent or received via a transmission medium. For example, when software is sent from a website, server, or other remote resource using wired technologies (coaxial cable, optical fiber, twisted pair, digital subscriber line (DSL), etc.) and / or wireless technologies (infrared, microwave, etc.), these wired and / or wireless technologies are included within the definition of transmission medium.

[0257] The terms “system” and “network” used in this manual are interchangeable.

[0258] In this manual, the terms "base station (BS)," "wireless base station," "eNB," "gNB," "cell," "sector," "cell group," "carrier," and "component carrier" are used interchangeably. Base stations are sometimes also referred to as fixed stations, NodeBs, eNodeBs (eNBs), access points, transmitting points, receiving points, femtocells, small cells, etc.

[0259] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which can also provide communication services through a base station subsystem (e.g., an indoor small cell (remote radio head (RRH))). Terms such as "cell" or "sector" refer to a portion or the entire coverage area of ​​the base station and / or base station subsystem that provides communication services within that coverage area.

[0260] In this specification, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" are used interchangeably. A mobile station is sometimes also referred to by those skilled in the art as a user station, mobile unit, user unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile client, client, or several other appropriate terms.

[0261] Furthermore, the base station in this specification can also be replaced by a terminal. For example, various methods / implementations of this disclosure can also be applied to a structure that replaces communication between the base station and the terminal with communication between multiple terminals (D2D, Device-to-Device). In this case, the functions of the base station 600 described above can be regarded as the functions of the terminal. In addition, terms such as "uplink" and "downlink" can also be replaced with "side". For example, the uplink channel can also be replaced with the side channel.

[0262] Similarly, the terminal in this specification can also be replaced by a base station. In this case, the functions of the terminal 500 described above can be regarded as the functions of the base station.

[0263] In this specification, specific actions performed via a base station may sometimes also be performed via its upper node, depending on the circumstances. Clearly, in a network consisting of one or more network nodes with a base station, various actions performed for communication with a terminal can be performed via the base station, one or more network nodes other than the base station (considering, but not limited to, Mobility Management Entities (MMEs), Serving Gateways (S-GWs), etc.), or combinations thereof.

[0264] The various methods / implementations described in this specification can be used individually or in combination, and can be switched during execution. Furthermore, the processing steps, sequences, flowcharts, etc., of the various methods / implementations described in this specification can be rearranged as long as there are no contradictions. For example, regarding the methods described in this specification, various step units are given in an exemplary order, but the method is not limited to the specific order given.

[0265] The methods / implementations described in this specification can be applied to systems utilizing Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), Super 3G, IMT-Advanced, 4G, 5G, 6G, Future Radio Access (FRA), New-RAT, New Radio (NR), New Radio Access (NX), Future Generation Radio Access (FX), Global System for Mobile Communications (GSM), CDMA3000, Ultra Mobile Broadband (UMB), and IEEE... Systems based on and / or extended from IEEE 920.11 (Wi-Fi, a registered trademark), IEEE 920.16 (WiMAX, a registered trademark), IEEE 920.20, Ultra-Wideband (UWB), Bluetooth (Bluetooth, a registered trademark), other suitable wireless communication methods, and / or next-generation systems based on them.

[0266] The use of the word "based on" in this specification, unless explicitly stated elsewhere, does not imply "based on only". In other words, the use of "based on" refers to both "based on only" and "based on at least".

[0267] Any reference to units using the names "first," "second," etc., as used in this specification is not intended to fully define the number or order of these units. These names may be used in this specification as a convenient method of distinguishing two or more units. Therefore, reference to a first unit and a second unit does not imply that only two units may be used, or that the first unit must take precedence over the second unit in some form.

[0268] The term "determining" as used in this specification sometimes encompasses a variety of actions. For example, "determining" can refer to actions such as calculating, computing, processing, deriving, investigating, looking up (e.g., searching in tables, databases, or other data structures), and ascertaining. Furthermore, "determining" can also refer to actions such as receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, and accessing (e.g., accessing data in memory). Additionally, "determining" can refer to actions such as resolving, selecting, choosing, establishing, and comparing. In other words, "determining" can encompass several actions.

[0269] As used in this specification, the terms "connected," "coupled," or any variations thereof refer to any direct or indirect connection or combination between two or more units, including situations where one or more intermediate units exist between two mutually "connected" or "coupled" units. The combination or connection between units can be physical, logical, or a combination of both. For example, "connected" can also be replaced by "accessed." In this specification, it can be understood that two units are "connected" or "coupled" by using one or more wires, cables, and / or printed electrical connections, and, as several non-limiting and non-exhaustive examples, by using electromagnetic energy with wavelengths in the radio frequency region, microwave region, and / or light (both visible and invisible light) region.

[0270] When the terms "including," "comprising," and variations thereof are used in this specification or claims, these terms are open-ended, just like the term "possess." Furthermore, the term "or" as used in this specification or claims is not an XOR expression.

[0271] The present disclosure has been described in detail above; however, it will be apparent to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered ways without departing from the spirit and scope defined by the claims. Therefore, the description herein is for illustrative purposes only and is not intended to be restrictive.

Claims

1. A terminal in a communication system, comprising: The receiving unit is configured to receive first information from a base station in the communication system for indicating a first parameter, wherein the first parameter represents the number of candidate transform domain vectors of the precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system. The receiving unit is further configured to receive from the base station second information for indicating a second parameter, wherein the second parameter represents the number of transform domain vectors for determining the precoding matrix at the subcarrier level; as well as The control unit is configured to determine the number of transform domain vectors indicated by the second information from the number of candidate transform domain vectors indicated by the first information.

2. The terminal as claimed in claim 1, wherein the second information is used to indicate a first factor corresponding to the value of the second parameter, and the first factor is used together with the first parameter to determine the value of the second parameter.

3. The terminal of claim 1, wherein the control unit is further configured to determine the precoding matrix indication information at least based on the determined transform domain vector.

4. The terminal as claimed in any one of claims 1 to 3, wherein the receiving unit is further configured to receive from the base station indication information for indicating a subset of the candidate transform domain vectors, and the control unit is configured to determine from the subset the number of transform domain vectors indicated by the second information.

5. The terminal as claimed in claim 4, wherein the indication information includes third information for indicating a third parameter, wherein the value of the third parameter represents the number of vectors included in the subset of the candidate transform domain vectors.

6. The terminal of claim 5, wherein the indication information includes fourth information for indicating a fourth parameter, wherein the fourth parameter is used to determine the vectors included in the subset of the candidate transform domain vectors.

7. The terminal as described in claim 3, further comprising: The transmitting unit is configured to transmit the precoding matrix indication information to the base station.

8. The terminal as described in any one of claims 1 to 3, further comprising: The transmitting unit is configured to transmit rank indication information to the base station, wherein the rank indication information is used to indicate the rank for the terminal, and the value of the rank for the terminal is greater than or equal to four.

9. A base station in a communication system, comprising: The control unit is configured to determine a first parameter, wherein the first parameter represents the number of candidate transform domain vectors of the precoding matrix at the subcarrier level, and the value of the first parameter is less than the number of subcarriers in the communication system. The control unit is further configured to determine a second parameter, wherein the second parameter represents the number of transform domain vectors used to determine the precoding matrix at the subcarrier level; as well as The sending unit is configured to send first information indicating the first parameter and second information indicating the second parameter to a terminal in the communication system.

10. The base station as described in claim 9, further comprising: The receiving unit is configured to receive precoding matrix indication information from the terminal.

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