Channel state information feedback method, channel state information receiving method, communication apparatus and storage medium

Abstract

The embodiments of the present disclosure provide a channel state information feedback method, a channel state information receiving method, a communication apparatus and a storage medium, which relate to the technical field of communications, and can improve the matching accuracy between a codebook feedback solution and an actual channel. The channel state information feedback method comprises: a first node receives a measurement reference signal sent by a second node; the first node determines a precoding matrix on a plurality of subbands on the basis of the measurement reference signal, each column of the precoding matrix corresponding to one data transmission layer; the first node determines channel state information on the basis of the determined precoding matrix; and the first node sends the channel state information to a third node.

Description

Channel state information feedback and reception method, communication device, and storage medium

[0001] This disclosure claims priority to Chinese patent application No. 202410417527.8, filed on April 3, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of communication technology, and in particular to a method for feeding back and receiving channel state information, a communication device, and a storage medium. Background Art

[0003] With the widespread adoption of multiple input multiple output (MIMO) technology, transmitting devices (e.g., base stations) and receiving devices (e.g., terminals) can communicate using multiple antennas. For example, MIMO systems adjust the base station's beam direction using a precoding matrix that matches the channel between the base station and the terminal. This allows them to process spatially multiplexed data streams (i.e., spatial streams or data transmission layers) between the base station and the terminal, improving the reception quality of the spatial streams.

[0004] Currently, when a base station and a terminal communicate through a MIMO system, the base station can determine the precoding vector corresponding to each data transmission layer from the codebook (i.e., the column vector in the precoding matrix) based on the beam index fed back by the terminal and the beam index difference between the layers, and then adjust the beam direction based on the precoding column vector corresponding to each data transmission layer to achieve communication with the terminal.

[0005] However, the beam index difference fed back by the terminal is constant across the entire bandwidth. However, as bandwidth and the number of antennas increase, the dispersion problem in the actual channel becomes more prominent, causing the matching accuracy between the codebook feedback scheme and the actual channel to continue to decrease. Summary of the Invention

[0006] The embodiments of the present disclosure provide a method, device, and storage medium for feedback and reception of channel state information, which can improve the matching accuracy between a codebook feedback scheme and an actual channel.

[0007] In one aspect, a channel state information feedback method is provided, applied to a first node, comprising: receiving a sounding reference signal sent by a second node; determining a precoding matrix for multiple subbands based on the sounding reference signal, where each column of the precoding matrix corresponds to a data transmission layer; determining channel state information based on the determined precoding matrix; and sending the channel state information to a third node.

[0008] On the other hand, a method for receiving channel state information is provided, which is applied to a third node, including: receiving channel state information fed back by a first node, where the channel state information is determined by a precoding matrix on multiple subbands determined by the first node based on a measurement reference signal, and each column of the precoding matrix corresponds to a data transmission layer.

[0009] On the other hand, a channel state information feedback device is provided, which is applied to a first node and includes: a receiving module, a processing module, and a sending module.

[0010] The receiving module is configured to receive a sounding reference signal sent by the second node. The processing module is configured to determine a precoding matrix for multiple subbands based on the sounding reference signal, where each column of the precoding matrix corresponds to a data transmission layer. The processing module is further configured to determine channel state information based on the determined precoding matrix. The sending module is configured to send the channel state information to the third node.

[0011] On the other hand, a device for receiving channel state information is provided, which is applied to a third node and includes: a receiving module.

[0012] The receiving module is used to receive channel state information fed back by the first node, where the channel state information is determined by a precoding matrix on multiple subbands determined by the first node based on a measurement reference signal, and each column of the precoding matrix corresponds to a data transmission layer.

[0013] In yet another aspect, a communication node is provided, comprising: a memory and a processor. The memory and the processor are coupled. The memory is configured to store a computer program. When the processor executes the computer program, the method for feedback and reception of channel state information according to any of the above embodiments is implemented.

[0014] On the other hand, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the method for feedback and reception of channel state information described in any of the above aspects is implemented.

[0015] On the other hand, a computer program product is provided, which includes computer program instructions, and when the computer program instructions are executed, the channel state information feedback and reception method described in any one of the above aspects is implemented.

[0016] The disclosed embodiment discloses that by determining the vector index difference between layers along with the subband, it is possible to ensure that the codebook feedback scheme is well matched with the characteristics of the actual channel, thereby improving the matching accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings.

[0018] FIG1 is a schematic diagram of a communication system provided by some embodiments of the present disclosure;

[0019] FIG2 is a schematic flow chart of a method for feeding back channel state information provided by some embodiments of the present disclosure;

[0020] FIG3 is a schematic flow chart of a channel state information interaction method provided by some embodiments of the present disclosure;

[0021] FIG4 is a first structural diagram of a channel state information feedback device provided by some embodiments of the present disclosure;

[0022] FIG5 is a second structural diagram of a device for receiving channel state information provided by some embodiments of the present disclosure;

[0023] FIG6 is a third structural diagram of a channel state information feedback device provided by some embodiments of the present disclosure. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions of this disclosure in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of this disclosure, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0025] It should be noted that in this disclosure, words such as "exemplarily" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this disclosure as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplarily" or "for example" is intended to present the relevant concepts in a concrete manner.

[0026] In the following, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Therefore, a feature defined with the terms "first," "second," etc., may explicitly or implicitly include one or more of such features.

[0027] In the description of this disclosure, unless otherwise specified, " / " means "or." For example, A / B can mean A or B. "And / or" in this document simply describes an association relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exists simultaneously, and B exists alone. Furthermore, "at least one" means one or more, and "a plurality" means two or more.

[0028] In the existing channel state information (CSI) type I codebook reporting, the terminal receives a measurement reference signal sent by the base station, obtains a channel response between the base station and the terminal based on the received measurement reference signal, and obtains a precoding matrix based on the measured channel response.

[0029] When the precoding matrix includes precoding vectors for multiple data transmission layers (hereinafter referred to as "layers"), in the existing new radio (NR) type I codebook feedback, the terminal does not independently feedback the vector index corresponding to the precoding vector of each layer, but only independently feedbacks the vector index of the precoding vector of a reference layer. For each other layer, the terminal only needs to determine the vector index difference between the precoding vector of this layer and the precoding vector of the reference layer.

[0030] For example, in the existing 5G NR Type I codebook, when the antenna is a one-dimensional antenna, the vector index of each precoding vector includes a single value. In this case, it can also be considered to include two index values, but one of the index values ​​is a fixed value. When the antenna is a two-dimensional antenna, the vector index of each precoding vector includes two values. For example, one of the two values ​​corresponds to the vector index difference in a first direction, and the other value corresponds to the vector index difference in a second direction. For example, the first direction and the second direction include the horizontal direction and the vertical direction.

[0031] However, in the existing fifth-generation mobile communication technology (5G) NR CSI type I codebook feedback, the beams between layers are adjacent beams. The angular range of multi-layer coverage will decrease with the increase of the number of antennas, and the matching degree with the spatial sparsity of the actual channel will also decrease with the increase of the number of antennas.

[0032] Furthermore, the vector index differences in different directions do not change across subbands and remain constant across the entire CSI feedback bandwidth. As the bandwidth and number of antennas increase, this codebook feedback scheme cannot properly match the actual channel characteristics, thus reducing matching accuracy.

[0033] In other words, in the existing 5G NR CSI type I codebook feedback, the beam index difference between layers is constant across the entire bandwidth, and each layer can determine a beam for each subband separately, but the beams corresponding to all subbands are relatively concentrated. Therefore, as the bandwidth and number of antennas increase, the dispersion problem in the actual channel becomes more prominent, causing the matching between the terminal's precoding based on the existing 5G NR CSI type I codebook feedback and the actual channel to continue to deteriorate as the bandwidth and number of antennas increase.

[0034] In summary, in the future 5G-A (5G-Advanced, 5G enhanced) and sixth generation mobile communication technology (6G), the number of antennas and bandwidth will continue to increase. It is necessary to provide a codebook feedback scheme that better matches the actual channel for application scenarios with massive MIMO and large communication bandwidth.

[0035] That is, as the bandwidth and number of antennas increase, the beam relationship between multiple layers in the existing Type I codebook needs to be enhanced. On the one hand, this takes into account the dispersion problem, and on the other hand, it takes into account the shrinking angle range covered by each beam.

[0036] To address these technical issues, the present disclosure provides a method for channel state information feedback and reception. By determining the vector index difference between layers on a subband basis, this method ensures that the codebook feedback scheme closely matches the characteristics of the actual channel, improving matching accuracy. Furthermore, by independently selecting the vector index for each layer, the angular range of multi-layer coverage can be expanded, further improving the matching between the codebook feedback scheme and the spatial sparsity of the actual channel.

[0037] The network architecture of the mobile communication network (including but not limited to 3G, 4G, 5G and future mobile communication networks) in the embodiment of the present disclosure may include at least a first communication node and a second communication node. It should be understood that in this example, in the downlink, the first communication node may be a terminal side device (for example, including but not limited to a terminal), and the second communication node (and / or the third communication node) may be a network side device (for example, including but not limited to a base station). Of course, in the uplink, the first communication node may also be a network side device, and the second communication node (and / or the third communication node) may also be a terminal side device. In the device-to-device communication of the three communication nodes, the first communication node, the second communication node and the third communication node may all be base stations or terminals. The first communication node, the second communication node and the third communication node may be referred to as the first node, the second node and the third node, respectively.

[0038] For example, taking the first communication node as a terminal and the second and third communication nodes as base stations, FIG1 shows a communication system provided by an embodiment of the present disclosure, which includes a first node (e.g., terminal 101), a second node (e.g., base station 102), and a third node (e.g., base station 103). The terminal 101 may be one or more, and the number is not limited.

[0039] In some embodiments, the base station 102 is configured to send a measurement reference signal to the terminal 101 so that the terminal 101 can determine a coding matrix for managing the beam.

[0040] The terminal 101 is configured to respond to the measurement reference signal sent by the base station 102 and send the beam index difference of each subband to the base station 103 for each subband layer, thereby instructing the base station 103 to adjust the beam direction.

[0041] The base station 103 is configured to adjust the beam direction by querying a codebook according to the beam index differences of multiple subbands fed back from the terminal 101 .

[0042] It should be noted that, in the embodiments of the present disclosure, the second node and the third node may be the same node (i.e., base station 102 and base station 103 may be the same base station). Alternatively, the second node and the third node may be two different nodes (i.e., base station 102 and base station 103 may be two different base stations).

[0043] In some embodiments, the base station (BS) can be a base station or an evolved base station (eNB or eNodeB) in LTE (long term evolution), long term evolution advanced (LTEA), a base station device in a fifth generation wireless systems (5G) network, or a base station in a future communication system, etc. The base station can include various macro base stations, micro base stations, home base stations, wireless remote devices, reconfigurable intelligent surfaces (RISs), routers, relays, TRPs, wireless fidelity (WIFI) devices and other network side devices.

[0044] In some embodiments, the terminal may be a device with wireless transceiver capabilities. The terminal may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present disclosure do not limit the application scenarios. The terminal may sometimes also be referred to as a user, user equipment (UE), access terminal, UE unit, UE station, mobile station, mobile station, remote station, remote terminal, mobile device, UE terminal, wireless communication device, UE agent or UE device, etc., and the embodiments of the present disclosure do not limit this.

[0045] It should be noted that Figure 1 is only an exemplary framework diagram. The number of devices included in Figure 1 and the names of each device are not limited. In addition to the devices shown in Figure 1, the communication system may also include other devices, such as core network devices.

[0046] The application scenarios of the embodiments of the present disclosure are not limited. The system architecture and business scenarios described in the embodiments of the present disclosure are intended to more clearly illustrate the technical solutions of the embodiments of the present disclosure and do not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. It is understood by those skilled in the art that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided by the embodiments of the present disclosure are also applicable to similar technical problems.

[0047] Fig. 2 shows a schematic flow chart of a method for feeding back channel state information. As shown in Fig. 2, the method for feeding back channel state information includes: S201-S204.

[0048] S201: A first node receives a sounding reference signal sent by a second node.

[0049] S202: The first node determines a precoding matrix on multiple subbands according to a measurement reference signal.

[0050] As a possible implementation method, the subband division can be based on at least one of the following: a predetermined rule, signaling notified by the base station, the bandwidth corresponding to the bandwidth part (BWP), the bandwidth corresponding to the component carrier (CC) of a carrier, and the frequency domain reference point of the common physical resource block.

[0051] In some embodiments, the above-mentioned sub-band division and the sub-band division strategy, sub-band size, and sub-band division for feeding back channel quality indicator (CQI) may be the same or different.

[0052] In the embodiment of the present disclosure, each column of the precoding matrix corresponds to a data transmission layer.

[0053] As a possible implementation, the precoding matrix includes at least one column, and a vector index of the at least one column is determined separately for multiple subbands. The first phase corresponding to each column in the at least one column is the same across the multiple subbands. In each of the multiple subbands, a vector corresponding to the second half of the elements of the column is determined by multiplying the first phase by the vector corresponding to the first half of the elements of the column.

[0054] In some embodiments, the column corresponding to each layer in the precoding matrix may be a precoding vector, and the precoding vector corresponding to each layer is determined based on a third vector. The third vector is determined based on a first vector and a second vector, where the number of elements in the first vector is a first number N1, and the number of elements in the second vector is a second number N2.

[0055] For example, a precoding vector is formed by the Kronecker product of two vectors of length N1 and N2, wherein the first vector of length N1 (i.e., the number of elements in the first vector is the first number N1) The nth element of has the following form:

[0056] A second vector of length N2 (i.e., the number of elements in the second vector is the second number N2) The pth element of has the following form:

[0057] The length of the third vector obtained from these two vectors is N1·N2 (that is, the number of elements in the third vector above) The p·N1+nth element of has the following form:

[0058] As a possible implementation manner, the number of elements in each precoding vector is twice the product of the corresponding first number N1 and the corresponding second number N2.

[0059] Exemplarily, the precoding vector corresponding to a column has the following form:

[0060] in, This is the first phase, which can also be called the polarization phase difference. for The vector corresponding to the first half of the elements in , for The vector corresponding to the second half of the elements.

[0061] It should be noted that the embodiment of the present disclosure is for vector The specific form of is not limited. For example, The phase of each element of only includes the first term of the element index. For example, The phase of each element of includes the term greater than 1 of the index of this element.

[0062] For example:

[0063] Wherein, d1 is a real number, or 0≤d1<1.

[0064] Wherein, d2 is a real number, or 0≤d2<1.

[0065] It should be noted that for layer l, the above m1 and m2 can also be replaced by m 1，l and m 2，l , l∈{0, 1, ...RI-1}, RI represents the total number of layers. l will be ignored in the following description.

[0066] It should be noted that the above-mentioned first vector, second vector, and third vector may also be referred to as a first-category vector, a second-category vector, and a third-category vector, respectively.

[0067] In the embodiment of the present disclosure, the precoding matrix satisfies the following characteristics: the precoding matrix includes two columns; the first node determines the vector index difference corresponding to the two columns on each subband of the multiple subbands.

[0068] That is to say, the total number of layers can be 2, including only one reference layer and one non-reference layer. The terminal can independently feedback the vector index of the precoding vector corresponding to only one layer (i.e., the reference layer), and other layers (i.e., the non-reference layer) can indicate the vector index of the precoding vector corresponding to the non-reference layer by feeding back the difference between the vector index of the precoding vector corresponding to the reference layer and the vector index of the precoding vector corresponding to the non-reference layer.

[0069] As a possible implementation, the precoding vector corresponding to a layer is determined based on a third vector. The vector index of the precoding vector can be represented by the third vector index of the third vector. Each of the two columns corresponds to a first vector and a second vector, and the vector index corresponding to each column in the two columns includes the vector index of the first vector and the vector index of the second vector. That is, a third vector index can include a first vector index and a second vector index.

[0070] Exemplarily, in combination with the above example, the third vector index may be the third vector The index (m1, m2) of the third vector has two index values ​​m1 and m2, and m1 is called the first vector The index of (i.e., the first vector index), m2 is called the second vector The index of (i.e., the second vector index).

[0071] In some embodiments, the vector index difference corresponding to the two columns includes at least one of the following: the vector index difference of the two first vectors corresponding to the two columns, and the vector index difference of the two second vectors corresponding to the two columns. That is, a vector index difference may include a first index difference and / or a second index difference. The first index difference corresponding to a non-reference layer is the difference between the first vector index of the precoding vector corresponding to the non-reference layer and the first vector index of the precoding vector corresponding to the reference layer. The second index difference corresponding to a non-reference layer is the difference between the second vector index of the precoding vector corresponding to the non-reference layer and the second vector index of the precoding vector corresponding to the reference layer.

[0072] Exemplarily, if the third vector index of the first data transmission layer (i.e., the reference layer) is (m1, m2), and the third vector index of the second data transmission layer (i.e., the non-reference layer) is (m1+k1, m2+k2), then the vector index difference between the first data transmission layer and the second data transmission layer is (k1, k2), where k1 is the first index difference and k2 is the second index difference.

[0073] Similarly, the multiple subbands may include: a reference subband. The vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference layer of the reference subband and the vector index of the first vector corresponding to the non-reference layer.

[0074] For example,

[0075] in, Used to indicate the vector index difference of the first vectors corresponding to the two columns on the reference subband s0, A vector index for indicating the first vector corresponding to the second layer (such as a non-reference layer) of the two layers on the reference subband s0, A vector index used to indicate the first vector corresponding to the first layer (such as the reference layer) of the two layers on the reference subband s0.

[0076] It should be noted that, in the embodiment of the present disclosure, the first node may determine the vector index difference by determining a set of candidate values ​​of the vector index difference.

[0077] For example, in the existing NR type I feedback, the terminal independently feeds back the first vector index m1∈{0, 1, ...N1O1-1} and the second vector index m2∈{0, 1, ...N2O2-1} corresponding to the first layer. For each other layer, the vector index difference with the first layer is determined to be (k1, k2). For each other layer, the corresponding vector index difference (k1, k2) is respectively determined. Specifically, the number, range, and acquisition method of the candidate values ​​of the vector index difference are shown in Table 1.

[0078] Table 1

[0079] As can be seen from Table 1, the first and second vector index differences between layers are fixed and do not change across subbands. However, in real channels, as the number of antennas and bandwidth increase, dispersion becomes significant, and the index differences between layers need to change across subbands. Furthermore, the third vectors between layers in Table 1 are adjacent orthogonal third vectors. For example, the terminal independently feeds back the third vector index corresponding to layer 1, i.e., the candidate value range for the third vector index of layer 1 is m1∈{0, 1, 2, 3, ...N1O1-1} and m2∈{0, 1, 2, 3, ...N2O2-1}. Each other layer separately determines its third vector index difference from layer 1, including the first vector index difference k1 and the second vector index difference k2. Each other layer corresponds to a combination value (k1, k2). However, for some layers, the candidate value for this combination value is fixed and does not require terminal feedback. For some layers, this combination value is the same, and for these multiple layers, only one combination value needs to be determined or fed back. However, in the existing Type I codebook, the range of candidate values ​​for the vector index difference is relatively small. The third vectors corresponding to multiple layers are always adjacent third vectors, and the vector index difference does not change across subbands. The former reduces the angular coverage of multiple layers as the number of antennas increases, while the latter cannot adapt to dispersion. In real channels, paths are sparsely distributed in the spatial domain. Therefore, the existing Type I codebook feedback strategy needs to be enhanced.

[0080] To this end, the embodiment of the present disclosure manages the codebook feedback strategy through the following three enhancement methods (i.e., enhancement method 1, enhancement method 2, and enhancement method 3).

[0081] Enhancement method 1: the vector index difference between layers changes with the sub-band, or the vector index difference between feedback layers needs to be determined for each sub-band.

[0082] Specifically, one or more of the following methods may be used to determine the vector index difference between layers in each sub-band.

[0083] Mode 1-1: The terminal feeds back the vector index difference between layers in each subband. Furthermore, the terminal may also feed back a vector index difference set. The terminal determines and / or feeds back the vector index difference in each subband, and the vector index difference of each subband belongs to the vector index difference set.

[0084] Mode 1-2: The terminal and the base station agree on a table, as shown in Table 2. When the total number of layers is 2, each column in Table 2 predetermines the first vector index difference Δ between layer 2 and layer 1 in each subband. i，j , i is the subband index, j is the column index of the candidate column, and the terminal only needs to feedback the column index j.

[0085] Table 2

[0086] In some embodiments, each element in each column may further include a first vector index difference Δ between layer 2 and layer 1 in each subband. 1，i，j and the second vector index difference Δ 2，i，j， The terminal feedback column index is sufficient, as shown in Table 3.

[0087] Table 3

[0088] In methods 1-3, the vector index differences between subbands are correlated, meet predetermined characteristics, and are derived based on a common parameter. The terminal provides feedback of this common parameter, and the vector index differences between subbands are derived based on a predetermined rule or formula. Furthermore, the predetermined formula includes at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target and reference subbands, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two layers in the reference subband, and the bandwidth of the downlink sounding reference signal. The precoding matrix or precoding vector is derived based on the downlink sounding reference signal.

[0089] That is, the vector index difference corresponding to two columns on the target subband in multiple subbands is determined based on at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target subband and the reference subband, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two columns on the reference subband, and the bandwidth size of the measurement reference signal.

[0090] For example, the total number of layers is 2, and the difference in the first vector indices between layer 1 and layer 2 is k1, where k1 is obtained according to the subband index, or different subband indices correspond to different k1. For example, in the first subband, the difference in the first vector indices between layer 2 and layer 1 is k 1，0 , and the difference in the first vector indices between layer 2 and layer 1 in subband s is k 1，s .

[0091] In one implementation, the multiple subbands may further include: multiple non-reference subbands, and the difference in the vector indices of the first vectors corresponding to two columns on any non-reference subband is determined according to the index difference between the non-reference subband and the reference subband, and the difference in the vector indices of the first vectors corresponding to two columns on the reference subband. That is, the terminal does not need to separately feedback the difference k in the first vector index on each subband 1，s , and the terminal only needs to feedback or determine and There is an association relationship between them, satisfying a predetermined feature. Alternatively, the difference in vector indices between different subbands is obtained according to the same parameter, and the terminal feedbacks this one parameter, and the difference in vector indices on all subbands is obtained according to this one parameter and a predetermined formula or a predetermined rule.

[0092] For example, the predetermined formula includes one of the following:

[0093] where s and s0 are respectively the subband indices of subband s and the reference subband s0. Subband s may be other subbands outside the reference subband. k 1,s is used to indicate the difference in the vector indices of the first vectors corresponding to two columns on the non-reference subband s, is used to indicate the difference in the vector indices of the first vectors corresponding to two columns on the reference subband s0.

[0094] r is a real number, or r satisfies at least one of the following characteristics: 0 < r < 1, or r is obtained according to the subband size and the carrier frequency, and r is a value notified by the base station. For example where f0 is the carrier frequency and Δf is the subband size.

[0095] a1 may be a fixed value, for example: 1, or a value notified by the base station, or may be a real number. In some embodiments, the terminal feedbacks the difference in the first vectors between layer 2 and layer 1 corresponding to the reference subband, and the difference in the first vectors between layer 2 and layer 1 corresponding to other subbands is obtained according to the above formula.

[0096] In the embodiments of the present disclosure, the base station notifies or agrees on the index and / or position of the reference subband. That is, the index of the reference subband or the position of the reference subband in the frequency domain is configured by the second node, or pre-agreed by the first node and the second node.

[0097] In some embodiments, the reference sub-band is located at the middle of a carrier frequency.

[0098] In one embodiment, although the index difference between layers will change with the subband, the vector index of the reference layer does not change with the subband. For example, if the total number of layers is 2, layer 1 is the reference layer, and the first vector index of layer 1 is m1, m1 does not change with the subband, that is, the first vector of layer 1 in each subband is The first vector difference between layer 2 and layer 1 in the reference subband is k 1，0 , the first vector index difference between layer 2 and layer 1 will be different for each subband and needs to be determined separately. That is, the index of the first vector of layer 2 will change with the subband, that is, the first vector index of layer 2 on subband s is m1+k 1，s The index characteristics of different layers are different. The vector index of some layers does not change with the subband, while the vector index of some layers changes with the subband. The vector index is determined separately on each sub-band, but the vector difference between the two polarization directions is It will not change with the sub-band.

[0099] In another embodiment, the vector index of the reference layer changes with the subband, and the vector index difference between layers also changes with the subband. For example, the total number of layers is 2, layer 1 is the reference layer, and the first vector index of layer 1 is m 1，s , m 1，s will change with each subband, where s is the subband index. That is, the first vector of layer 1 on each subband is The first vector difference between layer 2 and layer 1 in the reference subband is k 1，0 , the first vector index difference between layer 2 and layer 1 on each subband will be different and needs to be determined separately. That is, the index of the first vector of layer 2 will change with the subband, that is, the first vector index of layer 2 on subband s is m 1，s +k 1，s The index characteristics of different layers are the same, and the vector indexes of all layers need to be determined and fed back separately for each subband. The vector index is determined separately on each sub-band, but the vector difference between the two polarization directions is It will not change with the sub-band.

[0100] In another embodiment, the vector index difference between layers is obtained based on the vector index of the reference layer. 1，0 When it is greater than a predetermined value, the vector index difference between the layers needs to be determined separately for each sub-band; otherwise, the vector index difference between the layers is the same for each sub-band.

[0101] In one embodiment, the vector index difference between layers is determined based on the frequency domain bandwidth occupied by the downlink measurement reference signal. For example, when the frequency domain bandwidth occupied by the downlink measurement reference signal is greater than a predetermined value, the vector index difference between layers needs to be determined separately for each subband. Otherwise, the vector index difference between layers is the same for each subband.

[0102] The third vectors of the L layers obtained by the above method may not be orthogonal. Therefore, further agreement is required. If the L third vectors obtained by the above method are not orthogonal, the selected L vectors need to be corrected to make the L vectors orthogonal. For example, the combination of (first vector index, second vector index) corresponding to the two third vectors of the two layers obtained by the above method is as follows (m 1，1 , m 2，1 ), (m 1，2 , m 2，2 ), where Δ1 = m 1，2 -m 1，1 , Δ2=m 2，2 -m 2，1 , requiring that either Δ1 is an integer multiple of O1 and not 0, or Δ2 is an integer multiple of O2 and not 0. If this feature is not met, then either adjust m 1，1 and m 1，2 , so that Δ1 satisfies the above conditions, or adjust m 2，1 and m 2，2 To make Δ2 meet the above conditions, which one to adjust can be determined according to one of the following: N1, N2, Δ1, Δ2, m 1，1 and m 2，1 , for example, if at least one of the following conditions is met: N1 is greater than N2, Δ1 is greater than Δ2, or m 1，1 Greater than, m 2，1 , then adjust m 2，1 and m 2，2 Make Δ2 meet the above conditions, otherwise adjust m 1，1 and m 1，2 , so that Δ1 satisfies the above conditions.

[0103] Enhancement method 2: The terminal selects L orthogonal bases from a set of third vector orthogonal bases, and the L orthogonal bases are used as the third vectors of each layer in turn, so that the angle range covered by multiple layers can be increased or decreased as needed.

[0104] The orthogonality of the two third vectors includes the following cases: Case 1, the first vectors corresponding to the two third vectors are orthogonal; Case 2, the second vectors corresponding to the two third vectors are orthogonal.

[0105] It should be noted that there is no restriction on the second vector corresponding to the two third vectors in case 1, and there is no restriction on the first vector corresponding to the two third vectors in case 2. In order to obtain L orthogonal third vectors, the following solutions can be used:

[0106] Solution 2-1: Select a group of orthogonal first vectors, for example, select a group of first vector orthogonal bases from O1 groups of first vector orthogonal bases, for example, select a q1 value from q1∈{0, 1, ..., O1-1}, then select L orthogonal first vectors from N1 orthogonal first vectors, and then select L second vectors from N2O2 second vectors. The selected L orthogonal first vectors and L second vectors correspond one-to-one to constitute L orthogonal third vectors.

[0107] The above selection can also be considered as selecting L elements from a matrix with N1O1 rows and N2O2 columns, where each row in the matrix corresponds to a first vector and each column corresponds to a second vector. An element in the matrix is ​​a third vector determined by the first vector corresponding to the row of the element and the second vector corresponding to the column of the element. Different elements in the selected L elements correspond to different rows, and the L first vectors corresponding to these L rows are orthogonal. That is, L rows of elements are selected from N1 rows, and an element is selected from each row, where each row corresponds to a first orthogonal vector in the N1 first vector orthogonal basis, each row includes N2O2 elements, each column corresponds to a vector in the N2O2 second vectors, and each element in the row is a third vector formed by the first vector and the second vector.

[0108] In this case, N1≥L is required. The first vector index and the second vector index corresponding to the i-th third vector among the L orthogonal third vectors are selected in the following form: 1，i =m 11，i O1+q1,m 2，i =m 12，i At this time, the number of feedback bits required to feed back L orthogonal third vectors is At this time, the columns corresponding to the L elements selected in the L rows can be the same or different. Or the number of feedback bits required to feedback the L orthogonal third vectors is At this time, the columns corresponding to the L elements selected in the L rows are different, where The number of combinations of selecting Y numbers from X numbers. In this case, L orthogonal third vectors correspond to L orthogonal first vectors, and the angular spread corresponding to the L first vectors increases as L increases. The second vectors corresponding to the L orthogonal third vectors can be the same, non-orthogonal, or orthogonal.

[0109] Among them, m 11，i ∈{0, 1, ..., N1-1}, m 12，i∈{0, 1,...,N2O2-1}, q1∈{0, 1,...O1-1}, m 11，i There are L different values, i=0, 1, ...L-1.

[0110] Solution 2-2: Select a set of orthogonal second vectors. For example, select a set of orthogonal second vector bases from the O2 set of orthogonal second vector bases, for example, select a value q2 from q2∈{0, 1, ..., O2-1}. Then select L orthogonal second vectors from the N2 orthogonal first vectors, and then select L first vectors from the N2O2 first vectors. The L selected orthogonal second vectors correspond one-to-one with the L first vectors to form L orthogonal third vectors. This selection can also be thought of as selecting L rows of elements from N2 rows, with one element selected from each row. Each row corresponds to a second orthogonal vector from the N2 second vector bases, each row contains N1O1 elements, and each column corresponds to one of the N1O1 second vectors. Each element in the row is a third vector formed by the first and second vectors. In this case, N2 ≥ L is required.

[0111] At this time, the number of feedback bits required for feeding back L orthogonal third vectors is At this time, the columns corresponding to the L elements selected in the L rows can be the same or different. Or the number of feedback bits required to feedback the L orthogonal third vectors is In this case, the L elements selected in the L rows correspond to different columns. In this case, the L orthogonal third vectors correspond to L orthogonal second vectors, and the angular spread corresponding to the L second vectors increases as L increases. The first vectors corresponding to the L orthogonal third vectors can be the same, non-orthogonal, or orthogonal.

[0112] The first vector index and the second vector index corresponding to the i-th third vector among the L orthogonal third vectors are selected in the following form: 1，i =m 11，i , m 2，i =m 12，i O2+q2,m 11，i ∈{0, 1, ..., N1O1-1}, m 12，i ∈{0, 1,...,N2-1}, q2∈{0, 1,...O2-1}, m 12 , i There are L different values, i=0, 1, ...L-1.

[0113] Solution 2-3: Select a set of orthogonal first vectors and a set of orthogonal second vectors, for example, select a combination value of (q1, q2), where q2∈{0, 1, ..., O2-1} and q1∈{0, 1, ..., O1-1}. These first and second orthogonal vectors constitute N1N2 orthogonal third vectors, and select L third orthogonal vectors from these N1N2 orthogonal third vectors. The first and second vector indices corresponding to the i-th third vector selected from the L orthogonal third vectors are in the following form: m 1，i =m 11，i O1+q1,m 2，i =m 12，i O2+q2,m 11，i ∈{0, 1, ..., N1-1}, m 12，i ∈{0, 1,...,N2-1}, q2∈{0, 1,...O2-1}, q1∈{0, 1,...O1-1}, (m 11，i , m 12，i ) are different L combination values. i = 0, 1, ... L-1.

[0114] At this time, any two third vectors among the L orthogonal third vectors are either orthogonal to the first vector or the second vector. When the first vectors are orthogonal, the second vectors can be the same or different. When the second vectors are orthogonal, the first vectors can be the same or different.

[0115] At this time, the number of feedback bits required for feeding back L orthogonal third vectors is:

[0116] In one embodiment, based on at least one of the following: signaling information, N1, N2, L sent by the base station, it is determined to adopt one of the above-mentioned schemes 2-1, 2-2, and 2-3, or only one of schemes 2-1 and 2-2 is used. For example, based on at least one of the following: signaling information, N1, N2, and L sent by the base station, it is determined to adopt one of the above-mentioned schemes 2-1 and 2-3.

[0117] In one embodiment, the third vector indexes of the reference layer and the non-reference layer change with the subband, or need to be determined and / or fed back separately for each subband. The terminal feeds back L orthogonal third vectors, which serve as L reference third vectors corresponding to the L layers, and the third vector of each layer is selected from several third vectors around the reference third vector of this layer in each subband.

[0118] For example, the first and second vector index combinations corresponding to the third base vector of layer 1 are (m 1，1 , m 2，1), then the combination of (first vector index, second vector index) corresponding to the third vector of layer 1 in each subband belongs to the first set: {(m 1,1 ,m 2,1 ),(m 1,1 +1,m 2,1 ),(m 1,1 ,m 2,1 +1),(m 1,1 +1,m 2,1 +1)}

[0119] The base third vector index of layer 2 is (m 1，2 , m 2，2 ). Then the combination of (first vector index, second vector index) corresponding to the third vector of layer 2 in each subband belongs to the second set: {(m 1,2 ,m 2,2 ),(m 1,2 +1,m 2,2 ),(m 1,2 ,m 2,2 +1),(m 1,2 +1,m 2,2 +1)}.

[0120] If the terminal independently selects the third vector for layer 1 from the first set and the third vector for layer 2 from the second set, it will appear that the third vectors of layer 1 and layer 2 are not orthogonal on the same subband. For example, on a subband, the third vector of layer 1 is selected as (m 11，1 +1,m 12，1 ), the third vector of layer 2 is selected as (m 11，2 +1,m 12，2 +1), the third vectors of layers 1 and 2 are not orthogonal. Therefore, the terminal is required to jointly select L orthogonal third vectors corresponding to L layers in each band. For example, the terminal selects L orthogonal reference third vectors, forming L third vector sets as described above. The elements of these L third vector sets correspond to each other, forming X rows. Each row corresponds to L third vectors of L layers. The L third vectors are orthogonal and come from L third vector sets. This is shown in Table 4.

[0121] Table 4

[0122] That is, for each subband, the third vectors of the L layers are selected to meet agreed characteristics, such as orthogonality. For example, for each subband, the terminal only needs to select the row index in Table 4 above, and the L third vectors in each row are orthogonal. In this way, the terminal independently selects L reference third vectors, thereby obtaining L third vector sets. The terminal then selects L orthogonal third vectors from these L third vector sets for each subband. There is no limit on the third vector index difference between the L third vector sets, so that the angle range corresponding to multiple layers can be fed back on demand, and it also ensures that the third vectors corresponding to each layer on each subband are orthogonal.

[0123] Enhancement method 3: Apply enhancement method 1 based on enhancement method 2.

[0124] Furthermore, it can be agreed that when the first vector index difference corresponding to the reference third vector between layers is greater than a predetermined value, the first vector index difference between layers changes with the subband and needs to be determined separately for each subband; otherwise, the first vector index difference between layers does not change with the subband.

[0125] In some embodiments, it can be agreed that when the second vector index difference corresponding to the reference third vector between layers is greater than a predetermined value in the reference sub-band, the second vector index difference between the layers changes with the sub-band and needs to be determined separately for each sub-band. Otherwise, the second vector index difference between the layers does not change with the sub-band.

[0126] For example, the first vector difference k between layers 2 and 1 on subband s 1,s According to the following information For example, according to one of the following formulas: At this time, the first vector index difference can be a non-integer,

[0127] in, They are the first vector indices corresponding to layer 2 and layer 1 of the reference subband s0 respectively. The reference subband can also be the entire bandwidth, that is, including all subbands.

[0128] It should be noted that and The terminal needs to feedback to the base station instead of just feedback and The difference

[0129] The above gives the method of obtaining the vector difference between the first vectors of the layers. Similarly, the vector difference between the second vectors of the layers can also be obtained in the above way, except that a1 above is replaced by a2, k 1,0 Replace with k 2,0 , k1,i Replace with k 2,i . Replace with Where a1 and a2 can be equal or unequal.

[0130] For example, when the base station's transmit antenna spacing is the same in the horizontal and vertical directions, a1 and a2 are the same. When the base station's transmit antenna spacing is different in the horizontal and vertical directions, a1 and a2 are different. For example, the vector index of the second vector between layer 2 and layer 1 can be obtained similarly.

[0131] For example, the second vector difference k between layer 2 and layer 1 on subband s 2,s Determine based on the following information For example, one of the following formulas: In this case, the second vector index difference can be a non-integer,

[0132] in, They are the second vector indices corresponding to layer 2 and layer 1 of the reference subband s0 respectively. The reference subband can also be the entire bandwidth, that is, including all subbands.

[0133] It should be noted that for The terminals need to feed it back to the base station instead of just feeding it back Then feedback The difference k 2,0 .

[0134] Enhanced method 4: the expressions of the first vector and the second vector include subband indexes.

[0135] For example, in the s-th subband, the n-th element in the first vector is obtained according to the following formula:

[0136] Among them, m1∈{0,1,...N1O1-1}, n∈{0,1,...N1-1}.

[0137] On the sth subband, the second vector of length N2 The pth element of has the following form:

[0138] Among them, m2∈{0,1,...,N2O2-1}, p∈{0,1,...,N2-1}.

[0139] Where f1(s) and f2(s) are functions of the subband index s, g1(n,m1) is a function of the element index n and the vector index m1.

[0140] For example, f1(s i )=a1(1+(s i -s0)*r),f2(s i )=a2(1+(s i -s0)*r).

[0141] g1(n,m1) and g2(p,m2) are obtained according to one of the following formulas:

[0142] The function forms of g1(n,m1) and g2(p,m2) above are the same, but the input parameters are different. Then on subband s, the length of the third vector N1*N2 obtained by these two vectors is The p*N1+nth element of has the following form

[0143] On subband s, the precoding vector has the following form

[0144] At this time, the precoding vector The corresponding third vector varies with the subband, but the vector difference between the two polarization directions is It will not change with the sub-band.

[0145] It should be noted that the above method for determining the vector index or vector index difference between layer 1 and layer 2 can also be used in other two layers, such as between layer 3 and layer 4.

[0146] S203: The first node determines channel state information according to the determined precoding matrix.

[0147] The channel state information includes at least one of the following: precoding matrix indication (PMI), rank indication (RI), CQI (channel quantity indication), and layer indication (LI).

[0148] In some embodiments, the channel state information may include first indication information, where the first indication information includes information indicating a vector index difference corresponding to two columns on each subband of the plurality of subbands.

[0149] It should be noted that, for the description of the first indication information, reference may be made to the vector index difference set in the above-mentioned method 1-1, which will not be repeated here.

[0150] As a possible implementation method, the first indication information includes a target index, where the target index is an index in an index set, each index in the index set corresponds to multiple vector index differences, and each vector index difference in the multiple vector index differences is a vector index difference between two columns on a subband in multiple subbands.

[0151] It should be noted that, for the description of the target index, reference may be made to the index j of the candidate column in the above-mentioned method 1-2, which will not be repeated here.

[0152] In some embodiments, the first indication information includes a first parameter, and the vector index difference between two columns on each sub-band of the plurality of sub-bands is determined according to the first parameter and a predetermined formula or a predetermined rule.

[0153] It should be noted that, for the description of the first parameter, the predetermined formula and the predetermined rule, reference may be made to the introduction of the above-mentioned methods 1-3, which will not be repeated here.

[0154] In some other embodiments, the channel state information may include a vector index corresponding to a reference column (ie, a reference layer) of each subband in the plurality of subbands.

[0155] It should be noted that for the description of the vector index corresponding to the reference column of each subband in the channel state information including multiple subbands, reference can be made to the description in the above embodiment that when the frequency domain bandwidth occupied by the downlink measurement reference signal is greater than a predetermined value, the vector index difference between layers needs to be determined separately for each subband, which will not be repeated here.

[0156] In some embodiments, the channel state information may include a vector index corresponding to a reference column adapted for each subband in a plurality of subbands.

[0157] It should be noted that for the description of the channel state information including the vector index corresponding to the reference column adapted to each subband in multiple subbands, reference can be made to the above embodiment. When the frequency domain bandwidth occupied by the downlink measurement reference signal is less than or equal to a predetermined value, the vector index difference between layers is the same for each subband, and will not be repeated here.

[0158] In some other embodiments, the channel state information includes a vector index difference indicating first vectors corresponding to two columns on the reference subband.

[0159] As a possible implementation method, the vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column.

[0160] For example, The channel state information includes the and Information, including is the vector index of the first vector corresponding to the second layer of the two layers on the reference subband s0, is the vector index of the first vector corresponding to the first layer of the two layers on the reference subband s0.

[0161] S204: The first node sends channel state information to the third node.

[0162] In this way, by making the vector index difference between layers determined along the subband, it is possible to ensure that the codebook feedback scheme is well matched with the characteristics of the actual channel, thereby improving the matching accuracy.

[0163] It should be noted that in current Type I codebook feedback, for layer 1, the terminal feeds back a third vector index. Based on this third vector index and the agreed rules of the base station, a third vector set is determined. Then, for each subband or the entire bandwidth, the terminal selects a third vector from this third vector set as the third vector for this layer in this subband or the entire bandwidth, and feeds this selection information back to the base station. However, the current third vector set consists of several adjacent third vectors. As the number of antennas increases, the angular range covered by these adjacent third vectors is greatly reduced, making it unsuitable for scenarios with a large multipath angular range. For example, for layer 1, the first vector index and second vector index corresponding to the third vector fed back by the terminal are combined into (m1, m2), or if the terminal feeds back (m1 / 2, m2 / 2), they are converted to (m1, m2) according to the agreed rules. In the existing Type I codebook feedback scheme, the combination of the first vector index and the second vector index corresponding to the third vector in the determined third vector set includes (m1, m2), (m1, m2+1), (m1+1, m2), (m1+1, m2+1), or the combination of the first vector index and the second vector index corresponding to the third vector in the third vector set includes (m1, m2), (m1+1, m2), (m1+2, m2), (m1+3, m2), and the third vectors included in this third vector set are a set of third vectors with adjacent beam directions. As the number of antennas increases, the angular spread corresponding to the third vector included in this third vector set gradually decreases and needs to be enhanced. One or more of the following schemes (such as enhanced scheme A, enhanced scheme B, enhanced scheme C, and enhanced scheme D) can be adopted.

[0164] Enhanced solution A: Add a third vector set included in the third vector set, but at this time the number of bits used to determine the third vector from the third vector set for each subband or the entire bandwidth needs to be increased. For example, the indexes corresponding to the third vectors included in the third vector set include (m1, m2), (m1, m2+1), (m1+1, m2), (m1+1, m2+1), (m1+2, m2), (m1+2, m2+1), (m1, m2+2), and (m1+1, m2+2). At this time, the number of feedback bits used for terminal feedback to determine the third vector for each subband from the third vector set needs to be increased from the original 2 bits to 3 bits.

[0165] In some embodiments, the number of elements in the third vector set is determined based on at least one of N1 and N2. For example, when the maximum value of N1 and N2 is greater than a predetermined value, the number of elements in the third vector set is 8, and otherwise, the number is 4. The third vectors included in the third vector set have indices corresponding to (m1, m2), (m1+1, m2), (m1+2, m2), (m1+3, m2), (m1+4, m2), (m1+5, m2), (m1+6, m2), and (m1+7, m2), where N2 = 1. In this case, the third vectors included in the third vector set are still adjacent third vectors.

[0166] For example, as described above, the first vector index candidate values ​​included in the third vector set are arranged in sequence with an interval of 1, and the second vector index candidate values ​​included in the third vector set are arranged in sequence with an interval of 1.

[0167] Enhanced Solution B: The third vectors included in the third vector set are no longer continuous third vectors. After the first vector index candidate values ​​included in the third vector set are arranged in sequence, there exists a gap greater than 1 between at least two first vector index candidate values. Alternatively, after the second vector index candidate values ​​included in the third vector set are arranged in sequence, there exists a gap greater than 1 between at least two second vector index candidate values.

[0168] For example, the third vectors included in the third vector set include indexes (m1, m2), (m1, m2+a2), (m1+a1, m2), and (m1+a1, m2+a2), where a1 and a2 are integers greater than or equal to 1. At least one of a1 and a2 is obtained according to at least one of the following: signaling information notified by the base station, N1, N2, and a frequency domain bandwidth corresponding to the downlink sounding reference signal.

[0169] For example, the mapping function between a1 and N1 is a piecewise increasing function, and the mapping function between a2 and N2 is a piecewise increasing function. In this case, the number of elements included in the third vector set does not increase as at least one of N1 and N2 increases. The mapping function between at least one of a1 and a2 and the frequency domain bandwidth corresponding to the downlink sounding reference signal is a piecewise increasing function.

[0170] Enhanced solution C: a combination of enhanced solution A and enhanced solution B, that is, while increasing the number of elements in the third vector set, the index interval between the elements is increased.

[0171] Enhanced solution D: the above-mentioned enhanced solution 4 may also be adopted, so that the expressions of the first vector and the second vector include the subband index s.

[0172] In one implementation, when the maximum value of N1 and N2 is greater than a predetermined value, the enhanced solution AD is adopted; otherwise, the existing solution is adopted.

[0173] The above solution can be applied to layers 1 and 2 when the total number of layers is 2. When the total number of layers is 3 or 4, the above solution is applied to each layer 1-4 separately. However, as shown in the embodiments corresponding to enhancement methods 1-4 above, the third vector selection for each layer in each subband is not independent, but is jointly fed back.

[0174] In this way, by independently selecting the vector index of each layer, the angular range of multi-layer coverage can be extended to improve the matching between the codebook feedback scheme and the spatial sparsity of the actual channel.

[0175] In some embodiments, each column of the precoding matrix is ​​determined based on a weighted combination of multiple vectors; wherein the acquisition parameters of each vector of the multiple vectors include an index of a first type of subband, the acquisition parameters of the weighted combination include an index of a second type of subband, and the multiple subbands include at least one of the first type of subband and the second type of subband.

[0176] For example, on the first subband s and the second subband x, the upper half and the lower half of each layer in the precoding are formed by superimposing L third vectors. For example, the precoding vector of the lth layer has the following form:

[0177] The acquisition parameters of each third vector include the index s of the first-type subband. As described in the above enhancement method 4 and enhancement scheme D, where β i,x,l , β i+L,x,l is the weighting coefficient, β i,x,l , β i+L,x,l The acquired parameters include the second type subband index x. The granularity of change is the first type of sub-band, β i,x,l The change granularity is the second type of sub-band.

[0178] In some embodiments, the bandwidth of the first type of sub-band is greater than that of the second type of sub-band, and the first type of sub-band includes one or more second type of sub-bands.

[0179] As another possible implementation manner, the first-category sub-band and the second-category sub-band are of the same type.

[0180] As a possible implementation, β i ,x,β i+L,x,l Frequency domain compression, or frequency and time domain compression can be performed.

[0181] For example, for β i ,x,β i+L,x,l Perform frequency domain compression, where Among them, γ j,l , γ j+L,lis the weighting coefficient, y 3,x,j It can be called the frequency domain basis vector and can be obtained according to one of the following formulas:

[0182] For example, for β i ,x,β i+L,x,l Perform frequency domain and time domain compression. β i,x,t,l ,β i+L,x,t,l is β at time t i,x , β i+L,x,l , where γ i,j,c,l ,γ i+L,j,c,l is the weighting coefficient, e t,c It is called the time domain basis vector and can be obtained as follows:

[0183] In the above implementation, the subscripts of the frequency domain basis vectors and the time domain basis vectors do not carry the layer index l, that is, they are shared by all layers. Of course, it is not ruled out that they are determined separately for each layer, or separately for each layer group. In this case, the subscripts of the frequency domain basis vectors and / or the time domain basis vectors must be added with the layer index l, or the layer group index lg, and a layer group includes one or more layers.

[0184] In the above embodiment, the precoding matrices corresponding to the multiple subbands include a precoding matrix for each of the multiple subbands. Some information about the precoding matrices for different subbands of the multiple subbands is the same, while some information needs to be determined separately. The same information includes at least one of the following: the number of columns, the polarization phase difference φ corresponding to each column, the precoding information corresponding to the reference subband, and the precoding information corresponding to the wideband. The information that needs to be determined separately includes the vector index difference between two columns and the weighting coefficients between multiple vectors. The information that needs to be determined separately is also related to each other. For example, the information about the precoding matrix for each subband is determined based on the same parameters and predetermined rules or formulas.

[0185] For example, the precoding matrix on the first subband is W1, and the precoding matrix on the second subband is W2. W1 and W2 have some identical information and some different information. For example, W1 and W2 have the same number of columns, that is, the corresponding number of layers is the same. If each column of W1 and W2 is obtained by a third vector as described in Example 1, rather than by weighted combination of multiple third vectors, then for the same column index, the polarization phase φ corresponding to W1 and W2 is the same, and for different column indexes, the polarization phase φ corresponding to W1 and W2 is different. The vector index differences corresponding to W1 and W2 are different, but the vector index differences are all obtained according to the same formula or rule. Alternatively, the weighted basis vector sets corresponding to W1 and W2 are the same, but only the weighting values ​​are different.

[0186] In the above embodiment, the channel state information includes at least one of the following: PMI, RI, CQI, LI, and CRI.

[0187] The disclosed embodiment also provides a method for receiving channel state information.

[0188] The third node may receive channel state information fed back by the first node, where the channel state information is determined by a precoding matrix on multiple subbands determined by the first node based on a measurement reference signal, where each column of the precoding matrix corresponds to a data transmission layer.

[0189] It should be noted that, for the description of determining the channel state information, reference may be made to the introduction of the above embodiment, which will not be repeated here.

[0190] The following describes the channel state information interaction method (i.e., the channel state information feedback method and the channel state information receiving method) provided by the embodiments of the present disclosure in conjunction with some embodiments. As shown in FIG3 , the channel state information interaction method in the embodiments of the present disclosure may include:

[0191] S301: A second node sends a sounding reference signal to a first node.

[0192] S302: The first node receives a sounding reference signal sent by the second node.

[0193] S303: The first node determines a precoding matrix on multiple subbands based on the measurement reference signal.

[0194] S304: The first node determines channel state information according to the determined precoding matrix.

[0195] S305: The first node sends channel state information to the third node.

[0196] It should be noted that the third node and the second node may be the same node, or the third node and the second node may be two different nodes.

[0197] S306: The third node receives the channel state information fed back by the first node.

[0198] It is understandable that, in order to implement the above functions, the channel state information feedback device and the channel state information receiving device include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the algorithm steps of each example described in the embodiments of the present disclosure, the present disclosure can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven hardware manner depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present disclosure.

[0199] The embodiment of the present disclosure can divide the channel state information feedback device and the channel state information receiving device into functional modules according to the above-mentioned method embodiment. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one functional module. The above-mentioned integrated module can be implemented in the form of hardware or software. It should be noted that the division of modules in the embodiment of the present disclosure is schematic and is only a logical function division. There may be other division methods in actual implementation. The following is an example of dividing each functional module corresponding to each function.

[0200] Figure 4 is a schematic diagram of the structure of a channel state information feedback apparatus provided in an embodiment of the present disclosure. The channel state information feedback apparatus can implement the channel state information feedback method provided in the embodiments of methods S201-S204 above. As shown in Figure 4, channel state information feedback apparatus 400 includes a receiving module 401, a processing module 402, and a sending module 403.

[0201] Receiving module 401 is configured to receive a sounding reference signal sent by a second node. Processing module 402 is configured to determine a precoding matrix for multiple subbands based on the sounding reference signal, where each column of the precoding matrix corresponds to a data transmission layer. Processing module 402 is further configured to determine channel state information based on the determined precoding matrix. Transmitting module 403 is configured to send the channel state information to a third node.

[0202] In some embodiments, the precoding matrix satisfies the following characteristics: the precoding matrix includes two columns. The first node determines, on each subband of the plurality of subbands, a vector index difference corresponding to the two columns.

[0203] In some embodiments, the channel state information includes first indication information. The first indication information includes information indicating a vector index difference corresponding to two columns on each subband of the plurality of subbands.

[0204] In some embodiments, the first indication information includes a target index, where the target index is an index in an index set, each index in the index set corresponds to multiple vector index differences, and each vector index difference in the multiple vector index differences is a vector index difference between two columns on a subband in multiple subbands.

[0205] In some embodiments, the first indication information includes a first parameter, and the vector index difference between two columns on each sub-band of the plurality of sub-bands is determined according to the first parameter and a predetermined formula or a predetermined rule.

[0206] In some embodiments, the vector index difference corresponding to two columns on a target subband among multiple subbands is determined based on at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target subband and the reference subband, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two columns on the reference subband, and the bandwidth size of the measurement reference signal.

[0207] In some embodiments, the index of the reference subband or the position of the reference subband in the frequency domain is configured by the second node, or is pre-agreed upon by the first node and the second node.

[0208] In some embodiments, the channel state information includes a vector index corresponding to a reference column of each subband in the plurality of subbands.

[0209] In some embodiments, the channel state information includes a vector index corresponding to a reference column adapted for each subband in a plurality of subbands.

[0210] In some embodiments, each of the two columns corresponds to a first vector and a second vector, respectively, and the vector index corresponding to each of the two columns includes a vector index of the first vector and a vector index of the second vector. The vector index difference corresponding to the two columns includes at least one of the following: a vector index difference between the two first vectors corresponding to the two columns, and a vector index difference between the two second vectors corresponding to the two columns.

[0211] In some embodiments, the multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference between the first vectors corresponding to two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference between the first vectors corresponding to two columns on the reference subband.

[0212] In some embodiments, the channel state information includes a vector index difference indicating first vectors corresponding to two columns on the reference subband.

[0213] In some embodiments, the vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column.

[0214] In some embodiments, on the non-reference subband s, the vector index difference of the first vectors corresponding to the two columns is determined according to the following formula: Among them, a1, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the first vectors corresponding to the two columns on the reference subband s0.

[0215] In some embodiments, the multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the second vectors corresponding to two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the second vectors corresponding to two columns on the reference subband.

[0216] In some embodiments, the channel state information includes a vector index difference indicating a second vector corresponding to two columns on the reference subband.

[0217] In some embodiments, the vector index difference between the second vectors corresponding to the two columns on the reference subband is the difference between the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column.

[0218] In some embodiments, on the non-reference subband s, the vector index difference of the second vectors corresponding to the two columns is determined according to the following formula: Among them, a2, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the second vector corresponding to the two columns on the reference subband s0.

[0219] In some embodiments, a precoding matrix includes at least one column, a vector index of the at least one column is determined separately for multiple subbands, and a first phase corresponding to each column in the at least one column is the same across the multiple subbands. In each of the multiple subbands, a vector corresponding to the second half of the elements in the column is determined by multiplying the first phase by the vector corresponding to the first half of the elements in the column.

[0220] In some embodiments, each column of the precoding matrix is ​​determined based on a weighted combination of a plurality of vectors, wherein an acquisition parameter of each of the plurality of vectors includes an index of a first-category subband, an acquisition parameter of the weighted combination includes an index of a second-category subband, and the plurality of subbands includes at least one of the first-category subband and the second-category subband.

[0221] FIG5 is a schematic diagram of the structure of a channel state information receiving device provided by an embodiment of the present disclosure, which can execute the channel state information receiving method provided by the above embodiment. As shown in FIG5 , the channel state information receiving device 500 includes: a receiving module 501.

[0222] The receiving module 501 is used to receive channel state information fed back by the first node, where the channel state information is determined by a precoding matrix on multiple subbands determined by the first node based on a measurement reference signal, and each column of the precoding matrix corresponds to a data transmission layer.

[0223] In some embodiments, the precoding matrix satisfies the following characteristics: the precoding matrix includes two columns. The first node determines, on each subband of the plurality of subbands, a vector index difference corresponding to the two columns.

[0224] In some embodiments, the channel state information includes first indication information. The first indication information includes information indicating a vector index difference corresponding to two columns on each subband of the plurality of subbands.

[0225] In some embodiments, the first indication information includes a target index, where the target index is an index in an index set, each index in the index set corresponds to multiple vector index differences, and each vector index difference in the multiple vector index differences is a vector index difference between two columns on a subband in multiple subbands.

[0226] In some embodiments, the first indication information includes a first parameter, and the vector index difference between two columns on each sub-band of the plurality of sub-bands is determined according to the first parameter and a predetermined formula or a predetermined rule.

[0227] In some embodiments, the vector index difference corresponding to two columns on a target subband among multiple subbands is determined based on at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target subband and the reference subband, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two columns on the reference subband, and the bandwidth size of the measurement reference signal.

[0228] In some embodiments, the index of the reference subband or the position of the reference subband in the frequency domain is configured by the second node, or is pre-agreed upon by the first node and the second node.

[0229] In some embodiments, the channel state information includes a vector index corresponding to a reference column of each subband in the plurality of subbands.

[0230] In some embodiments, the channel state information includes a vector index corresponding to a reference column adapted for each subband in a plurality of subbands.

[0231] In some embodiments, each of the two columns corresponds to a first vector and a second vector, respectively, and the vector index corresponding to each of the two columns includes a vector index of the first vector and a vector index of the second vector. The vector index difference corresponding to the two columns includes at least one of the following: a vector index difference between the two first vectors corresponding to the two columns, and a vector index difference between the two second vectors corresponding to the two columns.

[0232] In some embodiments, the multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference between the first vectors corresponding to two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference between the first vectors corresponding to two columns on the reference subband.

[0233] In some embodiments, the channel state information includes a vector index difference indicating first vectors corresponding to two columns on the reference subband.

[0234] In some embodiments, the vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column.

[0235] In some embodiments, on the non-reference subband s, the vector index difference of the first vectors corresponding to the two columns is determined according to the following formula: Among them, a1, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the first vectors corresponding to the two columns on the reference subband s0.

[0236] In some embodiments, the multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the second vectors corresponding to two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the second vectors corresponding to two columns on the reference subband.

[0237] In some embodiments, the channel state information includes a vector index difference indicating a second vector corresponding to two columns on the reference subband.

[0238] In some embodiments, the vector index difference between the second vectors corresponding to the two columns on the reference subband is the difference between the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column.

[0239] In some embodiments, on the non-reference subband s, the vector index difference of the second vectors corresponding to the two columns is determined according to the following formula: Among them, a2, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the second vector corresponding to the two columns on the reference subband s0.

[0240] In some embodiments, a precoding matrix includes at least one column, a vector index of the at least one column is determined separately for multiple subbands, and a first phase corresponding to each column in the at least one column is the same across the multiple subbands. In each of the multiple subbands, a vector corresponding to the second half of the elements in the column is determined by multiplying the first phase by the vector corresponding to the first half of the elements in the column.

[0241] In some embodiments, each column of the precoding matrix is ​​determined based on a weighted combination of a plurality of vectors, wherein an acquisition parameter of each of the plurality of vectors includes an index of a first-category subband, an acquisition parameter of the weighted combination includes an index of a second-category subband, and the plurality of subbands includes at least one of the first-category subband and the second-category subband.

[0242] The solution provided by this patent addresses the issues of how to increase the spatial angles corresponding to multiple layers as the number of antennas increases, how to increase the spatial angle range corresponding to each layer across multiple subbands, and how to increase the angular spread between layers. This solution also considers the different precoding spatial angles corresponding to multiple subbands for a single transmission path due to dispersion. While taking into account feedback signaling overhead, it improves the match between the precoding matrix determined by the terminal and the channel characteristics. This provides an effective channel state information feedback solution for future large-scale antenna applications, or scenarios where large bandwidth and large-scale antennas are combined.

[0243] When the functions of the aforementioned integrated modules are implemented in hardware, embodiments of the present disclosure provide an alternative structure for the channel state information feedback apparatus described in the aforementioned embodiments. As shown in Figure 6 , the channel state information feedback apparatus 600 includes a processor 602 and a bus 604. In some embodiments, the channel state information feedback apparatus may also include a memory 601; in some embodiments, the channel state information feedback apparatus may also include a communication interface 603.

[0244] The processor 602 may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure. The processor 602 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The processor 602 may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure. The processor 602 may also be a combination that implements computing functions, for example, a combination of one or more microprocessors, a combination of a DSP (digital signal processor) and a microprocessor, and the like.

[0245] The communication interface 603 is used to connect to other devices via a communication network, such as Ethernet, wireless access network, or wireless local area network (WLAN).

[0246] The memory 601 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store dynamic information and instructions, an electrically erasable programmable read-only memory (EEPROM), a disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0247] As a possible implementation, the memory 601 may exist independently of the processor 602. The memory 601 may be connected to the processor 602 via a bus 604 for storing instructions or program codes. When the processor 602 calls and executes the instructions or program codes stored in the memory 601, the channel state information feedback method provided in the embodiment of the present disclosure can be implemented.

[0248] In another possible implementation, the memory 601 may also be integrated with the processor 602 .

[0249] Bus 604 can be an Extended Industry Standard Architecture (EISA) bus, for example. Bus 604 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, FIG6 shows bus 604 with only one thick line, but this does not mean that there is only one bus or only one type of bus.

[0250] In some embodiments, when the functions of the above-mentioned integrated modules are implemented in the form of hardware, the embodiments of the present disclosure provide another structure of the channel state information receiving device involved in the above-mentioned embodiments.

[0251] It should be noted that, for another structure of the channel state information receiving device, reference may be made to the channel state information feedback device 600 shown in FIG6 , which will not be described in detail here.

[0252] Some embodiments of the present disclosure provide a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium), which stores computer program instructions. When the computer program instructions are executed on a computer, the computer executes the channel state information feedback and reception method as described in any of the above embodiments.

[0253] For example, the computer-readable storage media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memories (EPROMs), cards, sticks, or key drives, etc.). The various computer-readable storage media described in this disclosure may represent one or more devices and / or other machine-readable storage media for storing information. The term "machine-readable storage medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data.

[0254] An embodiment of the present disclosure provides a computer program product including instructions. When the computer program product is run on a computer, the computer is enabled to execute the channel state information feedback and reception method described in any of the above embodiments.

[0255] The above is only a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or replacements within the technical scope disclosed in the present disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A channel state information feedback method, applied to a first node, wherein: The method comprises: receiving a measurement reference signal sent by the second node; determining, based on the measurement reference signal, a precoding matrix on a plurality of subbands, wherein each column of the precoding matrix corresponds to a data transmission layer; Determining channel state information according to the determined precoding matrix; The channel state information is sent to a third node.

2. The method according to claim 1, wherein The precoding matrix satisfies the following characteristics: The precoding matrix includes two columns; The first node determines a vector index difference corresponding to the two columns on each subband of the multiple subbands.

3. The method according to claim 2, wherein: The channel state information includes first indication information; the first indication information includes information indicating a vector index difference corresponding to the two columns on each subband of the multiple subbands.

4. The method according to claim 3, wherein: The first indication information includes a target index, where the target index is an index in an index set, each index in the index set corresponds to multiple vector index differences, and each vector index difference in the multiple vector index differences is a vector index difference between the two columns on one of the multiple subbands.

5. The method according to claim 3, wherein The first indication information includes a first parameter, wherein the vector index difference between the two columns on each subband of the multiple subbands is determined according to the first parameter and a predetermined formula or a predetermined rule.

6. The method according to claim 2, wherein: The vector index difference corresponding to the two columns on the target subband among the multiple subbands is determined based on at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target subband and the reference subband, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two columns on the reference subband, and the bandwidth size of the measurement reference signal.

7. The method according to claim 6, wherein: The index of the reference subband or the position of the reference subband in the frequency domain is configured by the second node, or is pre-agreed upon by the first node and the second node.

8. The method according to any one of claims 2 to 7, wherein The channel state information includes a vector index corresponding to a reference column of each subband in the plurality of subbands.

9. The method according to any one of claims 2 to 7, wherein The channel state information includes a vector index corresponding to a reference column adapted to each subband of the plurality of subbands.

10. The method according to any one of claims 2 to 9, wherein: Each of the two columns corresponds to a first vector and a second vector, respectively, and the vector index corresponding to each column in the two columns includes the vector index of the first vector and the vector index of the second vector; the vector index difference corresponding to the two columns includes at least one of the following: the vector index difference of the two first vectors corresponding to the two columns, and the vector index difference of the two second vectors corresponding to the two columns.

11. The method according to claim 10, wherein: The multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the first vectors corresponding to the two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the first vectors corresponding to the two columns on the reference subband.

12. The method according to claim 11, wherein The channel state information includes a vector index difference indicating a first vector corresponding to the two columns on the reference subband.

13. The method according to claim 11, wherein The vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column.

14. The method according to any one of claims 11 to 13, wherein On the non-reference subband s, the vector index difference of the first vectors corresponding to the two columns is determined according to the following formula: Wherein, a1, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the first vectors corresponding to the two columns on the reference sub-band s0.

15. The method according to claim 10, wherein The multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the second vectors corresponding to the two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the second vectors corresponding to the two columns on the reference subband.

16. The method according to claim 15, wherein The channel state information includes a vector index difference indicating a second vector corresponding to the two columns on the reference subband.

17. The method according to claim 15, wherein: The vector index difference of the second vectors corresponding to the two columns on the reference subband is the difference between the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column.

18. The method according to any one of claims 15 to 17, wherein: On the non-reference subband s, the vector index difference of the second vectors corresponding to the two columns is determined according to the following formula: Wherein, a2, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the second vectors corresponding to the two columns on the reference sub-band s0.

19. The method according to any one of claims 1 to 18, wherein There is at least one column in the precoding matrix, a vector index of the at least one column is determined respectively in the multiple subbands, and a first phase corresponding to each column in the at least one column is the same in the multiple subbands; In each subband of the multiple subbands, a vector corresponding to the second half of the elements in a column is determined by multiplying the vector corresponding to the first half of the elements in the column by the first phase.

20. The method according to any one of claims 1 to 18, wherein Each column of the precoding matrix is ​​determined according to a weighted combination of multiple vectors; The acquisition parameter of each of the multiple vectors includes an index of a first-type subband, the acquisition parameter of the weighted combination includes an index of a second-type subband, and the multiple subbands include at least one of the first-type subband and the second-type subband.

21. A method for receiving channel state information, applied to a third node, wherein: The method comprises: Channel state information fed back by the first node is received, where the channel state information is determined by a precoding matrix on multiple subbands determined by the first node based on a measurement reference signal, where each column of the precoding matrix corresponds to a data transmission layer.

22. The method according to claim 21, wherein The precoding matrix satisfies the following characteristics: The precoding matrix includes two columns; The first node determines a vector index difference corresponding to the two columns on each subband of the multiple subbands.

23. The method according to claim 22, wherein The channel state information includes first indication information; the first indication information includes information indicating a vector index difference corresponding to the two columns on each subband of the multiple subbands.

24. The method according to claim 23, wherein The first indication information includes a target index, where the target index is an index in an index set, each index in the index set corresponds to multiple vector index differences, and each vector index difference in the multiple vector index differences is a vector index difference between the two columns on one of the multiple subbands.

25. The method according to claim 23, wherein The first indication information includes a first parameter, wherein the vector index difference between the two columns on each subband of the multiple subbands is determined according to the first parameter and a predetermined formula or a predetermined rule.

26. The method according to claim 22, wherein The vector index difference corresponding to the two columns on the target subband among the multiple subbands is determined based on at least one of the following parameters: the index of the target subband, the index of the reference subband, the index difference between the target subband and the reference subband, the subband size, the carrier frequency, the ratio between the subband size and the carrier frequency, the vector index of one of the two columns on the reference subband, and the bandwidth size of the measurement reference signal.

27. The method according to claim 26, wherein The index of the reference subband or the position of the reference subband in the frequency domain is configured by the second node, or is pre-agreed upon by the first node and the second node.

28. The method according to any one of claims 22 to 27, wherein The channel state information includes a vector index corresponding to a reference column of each subband in the plurality of subbands.

29. The method according to any one of claims 22 to 27, wherein: The channel state information includes a vector index corresponding to a reference column adapted to each subband of the plurality of subbands.

30. The method according to any one of claims 22 to 29, wherein Each of the two columns corresponds to a first vector and a second vector respectively, and the vector index corresponding to each column in the two columns includes the vector index of the first vector and the vector index of the second vector; the vector index difference corresponding to the two columns includes at least one of the following: the vector index difference of the two first vectors corresponding to the two columns, and the vector index difference of the two second vectors corresponding to the two columns.

31. The method according to claim 30, wherein The multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the first vectors corresponding to the two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the first vectors corresponding to the two columns on the reference subband.

32. The method according to claim 31, wherein The channel state information includes a vector index difference indicating a first vector corresponding to the two columns on the reference subband.

33. The method according to claim 31, wherein The vector index difference between the first vectors corresponding to the two columns on the reference subband is the difference between the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the first vector corresponding to the reference column of the reference subband and the vector index of the first vector corresponding to the non-reference column.

34. The method according to any one of claims 31 to 33, wherein On the non-reference subband s, the vector index difference of the first vectors corresponding to the two columns is determined according to the following formula: Wherein, a1, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the first vectors corresponding to the two columns on the reference sub-band s0.

35. The method of claim 30, wherein: The multiple subbands include: a reference subband and multiple non-reference subbands, and the vector index difference of the second vectors corresponding to the two columns on any non-reference subband is determined based on the index difference between the non-reference subband and the reference subband, and the vector index difference of the second vectors corresponding to the two columns on the reference subband.

36. The method according to claim 35, wherein The channel state information includes a vector index difference indicating a second vector corresponding to the two columns on the reference subband.

37. The method according to claim 35, wherein The vector index difference of the second vectors corresponding to the two columns on the reference subband is the difference between the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column, and the channel state information includes information for indicating the vector index of the second vector corresponding to the reference column of the reference subband and the vector index of the second vector corresponding to the non-reference column.

38. The method according to any one of claims 35 to 37, wherein On the non-reference subband s, the vector index difference of the second vectors corresponding to the two columns is determined according to the following formula: Wherein, a2, r are real numbers, s0 is the index of the reference subband, is the vector index difference of the second vectors corresponding to the two columns on the reference sub-band s0.

39. The method according to any one of claims 21 to 38, wherein There is at least one column in the precoding matrix, a vector index of the at least one column is determined respectively in the multiple subbands, and a first phase corresponding to each column in the at least one column is the same in the multiple subbands; In each subband of the multiple subbands, a vector corresponding to the second half of the elements in a column is determined by multiplying the vector corresponding to the first half of the elements in the column by the first phase.

40. The method according to any one of claims 21 to 38, wherein Each column of the precoding matrix is ​​determined according to a weighted combination of multiple vectors; The acquisition parameter of each of the multiple vectors includes an index of a first-type subband, the acquisition parameter of the weighted combination includes an index of a second-type subband, and the multiple subbands include at least one of the first-type subband and the second-type subband.

41. A communication device comprising: memory and processor; The memory is coupled to the processor; The memory is used to store instructions executable by the processor; When the processor executes the instructions, the method according to any one of claims 1 to 40 is performed.

42. A computer-readable storage medium, wherein: The computer-readable storage medium stores computer instructions, which, when executed on a computer, enable the computer to perform the method according to any one of claims 1 to 40.

43. A computer program product, wherein The computer program product comprises computer instructions, which, when executed on a computer device, cause the computer device to perform the method according to any one of claims 1 to 40.

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