Channel state information feedback method, communication apparatus and storage medium

Abstract

The present disclosure provides a channel state information feedback method, an apparatus and a storage medium, which relate to the technical field of communications, and are used for reducing the feedback overhead of channel state information. The method comprises: receiving a reference signal; determining channel state information on the basis of the reference signal, wherein the channel state information comprises first precoding matrix indicator information, and second precoding matrix indicator information respectively corresponding to a plurality of sub-bands, the plurality of sub-bands comprise a first sub-band and a second sub-band, and the second precoding matrix indicator information of the first sub-band is determined on the basis of the second precoding matrix indicator information of the second sub-band; and sending the channel state information.

Description

Channel state information feedback method, communication device and storage medium

[0001] This disclosure claims priority to Chinese patent application No. 202410390978.7, filed on March 29, 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 channel state information feedback method, a communication device, and a storage medium. Background Art

[0003] Multiple-input, multiple-output (MIMO) technology is widely used in wireless communications. MIMO utilizes multiple antennas to simultaneously transmit and receive multiple data streams. Using spatial diversity and spatial multiplexing, multiple data streams are transmitted to different antennas, improving wireless channel efficiency and data transmission rates. Precoding is a key technical feature of MIMO, eliminating co-channel interference, improving system performance, and reducing receiver processing complexity.

[0004] In practical applications, the configuration of precoding depends on the channel state information between the transmitter and receiver. Channel state information can be obtained by transmitting a pilot signal on one side and performing measurement and feedback on the other side. For example, in the downlink, the terminal can measure the downlink reference signal and feedback the appropriate codeword to the base station in the form of precoding matrix indicator (PMI) information. The base station can configure downlink precoding based on this information to optimize data transmission. However, with the continuous development of wireless communication technology, the feedback requirements for channel state information are becoming increasingly higher. How to reduce the feedback overhead of channel state information is a technical problem that needs to be solved urgently in related fields. Summary of the Invention

[0005] Embodiments of the present disclosure provide a method, apparatus, and storage medium for feedback of channel state information, for reducing feedback overhead of channel state information.

[0006] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0007] In a first aspect, the present disclosure provides a method for feeding back channel state information, the method comprising:

[0008] receiving a reference signal;

[0009] determining, based on the reference signal, channel state information, the channel state information including first precoding matrix indication information and second precoding matrix indication information corresponding to each of the plurality of subbands; wherein the plurality of subbands include a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined based on the second precoding matrix indication information of the second subband;

[0010] Send channel status information.

[0011] In a second aspect, the present disclosure provides a communication device, the device comprising:

[0012] A receiving module, configured to receive a reference signal;

[0013] a determination module, configured to determine channel state information based on a reference signal, the channel state information comprising first precoding matrix indication information and second precoding matrix indication information corresponding to each of a plurality of subbands; wherein the plurality of subbands comprises a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined based on the second precoding matrix indication information of the second subband;

[0014] The sending module is used to send channel status information.

[0015] In a third aspect, the present disclosure provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for feeding back channel state information as provided in the first aspect above is implemented.

[0016] In a fourth aspect, the present disclosure provides a computer program product comprising computer instructions, which, when executed by a processor, implements the method for feeding back channel state information as provided in the first aspect above.

[0017] Based on the technical solution provided by the present disclosure, on the basis of using a hierarchical feedback structure (i.e., a feedback structure jointly indicated by first and second precoding indication information) for channel state information feedback, the subband to be fed back is further divided into a first subband and a second subband. Based on the correlation between the second precoding matrix indication information of the first subband and the second subband, the second precoding matrix indication information of the first subband can be determined based on the second precoding matrix indication information of the second subband. In other words, the second precoding indication information of the second subband and the second precoding indication information of the first subband can jointly indicate the precoding matrix corresponding to each first subband. In this way, while ensuring the accuracy of the indication of the precoding matrix corresponding to each first subband, the precoding indication information of the first subband is also compressed, thereby reducing the feedback overhead of the channel state information. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present invention and do not constitute a limitation to the technical solution of the present invention.

[0019] FIG1 is a schematic diagram of the architecture of a communication system provided by an embodiment of the present disclosure.

[0020] FIG2 is a schematic flow chart of a channel state information feedback method provided by an embodiment of the present disclosure.

[0021] FIG3 is a schematic diagram showing the composition of a communication device provided in an embodiment of the present disclosure.

[0022] FIG4 is a schematic structural diagram of a communication device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present disclosure.

[0024] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0025] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this disclosure, unless otherwise specified, "plurality" means two or more.

[0026] In the embodiments of the present disclosure, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present disclosure should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0027] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0028] As a key physical layer technology for the fourth-generation mobile communication technology (4G) and the fifth-generation mobile communication technology (5G), MIMO technology will play an increasingly important role in future wireless communication systems. By utilizing multiple transmitters and receivers to simultaneously transmit and receive signals, MIMO technology can fully utilize spatial resources, improve the channel capacity of the communication system, and increase data throughput without increasing the communication bandwidth, thereby improving the spectrum utilization of the communication system. The basic principles of MIMO technology lie in its spatial diversity and spatial multiplexing technologies. Spatial diversity technology transmits data streams to different antennas, thereby improving the utilization efficiency of the wireless channel and the data transmission rate. At the same time, spatial multiplexing technology allows multiple data streams to be transmitted to the receiving end simultaneously, thereby improving the reliability and stability of data transmission.

[0029] In MIMO technology, precoding is a key step and the foundation of array beamforming. The core of precoding configuration lies in accurately acquiring channel state information between the transmitter and receiver. By effectively utilizing this channel state information, precoding technology can optimize signal transmission and improve system performance. In practical applications, channel state information is typically acquired by transmitting a pilot signal and performing measurement and feedback on the other end. For example, in a downlink scenario, a terminal can measure the downlink reference signal to acquire channel state information and feed this information back to the base station. One feedback method is to feed back appropriate codewords to the base station in the form of precoding matrix indication information. The base station then configures downlink precoding for information transmission.

[0030] Wireless communications typically utilize large bandwidths to increase transmission capacity and meet growing data demands. For example, 5G systems utilize 100M bandwidth, and future wireless communication systems plan to utilize even higher frequency bands to achieve even greater communication bandwidth. However, because channel states are frequency-selective, meaning that channel states may differ at different frequencies, the entire communication bandwidth needs to be divided into several subbands to provide more refined feedback of channel state information. The amount of feedback information per subband and the number of subbands jointly determine the overall feedback overhead. The greater the amount of feedback information per subband and the greater the number of subbands, the greater the overall feedback overhead. To reduce feedback overhead, relevant standards often employ a codebook feedback approach. This approach uses a predefined codebook to quantify and characterize the channel state. Pilot signal measurements are used to select an appropriate codeword from the codebook to characterize the channel state, and only the information indicating that codeword, the PMI, is fed back. PMI feedback typically includes wideband indication information and narrowband indication information. The wideband indication information is used to determine indication information shared by multiple subbands within a bandwidth, such as a wideband codeword group information, that is, all subbands within the bandwidth can only select codewords from the codeword group determined by the wideband indication information, while the narrowband indication information is used to indicate the codewords of each subband.

[0031] However, as the sub-band bandwidth increases, the dispersion effect becomes more significant. The dispersion effect refers to the signal distortion caused by the different propagation speeds of different frequency components during signal transmission. This distortion is exacerbated as the bandwidth increases. For MIMO arrays, the dispersion effect can cause beam broadening or even beam splitting. Different sub-bands require different codeword configurations to combat the dispersion problem. When the bandwidth increases or the array dimension increases, more codewords are required to accurately describe the channel state, resulting in an increase in the number of codewords in the wideband codeword group. However, the increase in the number of codewords will lead to a sharp increase in feedback overhead. Therefore, how to reduce the feedback overhead of channel state information is a technical problem that needs to be solved urgently in related fields.

[0032] In view of this, the present disclosure provides a method for feedback of channel state information, the method comprising: receiving a reference signal; determining channel state information based on the reference signal, the channel state information comprising first precoding matrix indication information and second precoding matrix indication information corresponding to each of a plurality of subbands; wherein the plurality of subbands comprises a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined based on the second precoding matrix indication information of the second subband; and sending the channel state information. The first precoding indication information is used to determine a codeword set from a preset codebook, and the second precoding matrix is ​​used to determine the position of the codeword selected by the subband in the codeword set. Generally, the first and second precoding indication information are used to jointly indicate the position of the selected codeword in the codebook, i.e., the index of the codeword.

[0033] In this way, based on the use of a hierarchical feedback structure (i.e., a feedback structure jointly indicated by the first and second precoding indication information) for channel state information feedback, the subband to be fed back is further divided into a first subband and a second subband. Based on the correlation between the second precoding matrix indication information of the first and second subbands, the second precoding matrix indication information of the first subband can be determined based on the second precoding matrix indication information of the second subband. In other words, the second precoding indication information of the second subband and the second precoding indication information of the first subband can jointly indicate the precoding matrix corresponding to each first subband. This ensures the accuracy of the indication of the precoding matrix corresponding to each first subband while also compressing the precoding indication information of the first subband, thereby reducing the feedback overhead of the channel state information.

[0034] The method provided by the embodiments of the present disclosure can be applied to various communication systems. For example, the communication system can be a long-term evolution system, a 5G communication system, a Wi-Fi system, a communication system related to the third generation partnership project (3GPP), a future evolution communication system (such as a sixth generation (6G) communication system, etc.), or a system integrating multiple systems, etc., without limitation. The method provided by the embodiment of the present disclosure is described below using the communication system 100 shown in Figure 1 as an example. Figure 1 is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solution provided by the present disclosure.

[0035] FIG1 is a schematic diagram of the architecture of a communication system provided by an embodiment of the present disclosure. As shown in FIG1 , the communication system 100 may include one or more network devices 12 and one or more terminal devices 11. The terminal device 11 may be communicatively connected to the one or more network devices 12.

[0036] In some embodiments, the network device 12 can be used to implement functions such as resource scheduling, wireless resource management, and wireless access control of terminal devices. For example, it can be an evolution nodeB (eNB), a next-generation base station (gNB), a transmission receive point (TRP), a transmission point (TP), and some other access nodes. Depending on the size of the service coverage area provided, the base station can be divided into a macro base station for providing macro cells (Macro cell), a micro base station for providing micro cells (Pico cell), and a femto base station for providing femto cells (Femto cell). With the continuous evolution of wireless communication technology, future base stations may also adopt other names.

[0037] The terminal device 11 may also be referred to as a terminal, user equipment (UE), mobile station, mobile terminal, etc. For example, the terminal device 11 may be a mobile phone, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality terminal, an augmented reality terminal, a wireless terminal used in industrial control, a wireless terminal used in unmanned driving, a wireless terminal used in remote surgery, a wireless terminal used in transportation safety, a wireless terminal used in smart cities, a wireless terminal used in smart homes, etc. The embodiments of the present disclosure do not limit the specific device form used by the terminal.

[0038] In some embodiments, during a communication process, a network device sends data to a terminal device, and the terminal device receives the data sent by the network device. Thus, the network device can be referred to as a transmitter. Accordingly, the terminal device can be referred to as a receiver. Alternatively, when a terminal device sends data to a network device, the network device can be referred to as a receiver. Accordingly, the terminal device can be referred to as a transmitter.

[0039] It should be noted that Figure 1 is only an exemplary framework diagram. The number of devices or nodes included in Figure 1 and the names of each device are not restricted. In addition to the functional nodes shown in Figure 1, the communication system may also include other nodes or devices, such as core network devices.

[0040] 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. Those skilled in the art will appreciate 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 equally applicable to similar technical problems.

[0041] The embodiments provided by the present disclosure are described in detail below with reference to the accompanying drawings.

[0042] As shown in FIG2 , the present disclosure provides a method for feeding back channel state information, the method comprising:

[0043] S101: Receive a reference signal.

[0044] Exemplarily, the reference signal (RS) provided in the present disclosure includes multiple types of reference signals, such as a channel state information-reference signal (CSI-RS), a synchronization signal (SS), a demodulation reference signal (DMRS), a phase tracking reference signal (PTRS), a sounding reference signal (SRS), etc.

[0045] In wireless communication systems, in order to ensure the accuracy and reliability of communication, reference signals can be transmitted to perform operations such as channel estimation, signal demodulation, and measurement.

[0046] In one example, the received reference signal can be expressed in the form of the following formula (1): y = Hx + n Formula (1)

[0047] Where x is the reference signal, H is the channel matrix, n represents the noise term, and y is the received reference signal.

[0048] S102: Determine channel state information according to a reference signal, where the channel state information includes first precoding matrix indication information and second precoding matrix indication information corresponding to each of the plurality of subbands.

[0049] The first precoding matrix indication information is used to indicate a first precoding matrix set, which includes at least one precoding matrix. In other words, the first precoding matrix indication information indicates a range of selectable codewords within a communication bandwidth. Each subband within the communication bandwidth can select an appropriate codeword from this codeword set for feedback.

[0050] The second precoding matrix indication information is used to indicate a precoding matrix of a corresponding subband from the first precoding matrix set.

[0051] It should be noted that, since the number of precoding matrices included in the first precoding matrix set may be large in actual implementation, the feedback overhead required for directly feeding back the codeword index corresponding to the precoding matrix of each subband is large. However, by jointly indicating the precoding matrix corresponding to each subband by the above-mentioned first precoding indication information and the second precoding indication information, the feedback overhead can be reduced.

[0052] For example, a codebook contains 128 codewords, and the number of subbands that need feedback is 10. In this case, the feedback overhead of directly feeding back the codeword index corresponding to the precoding matrix of each subband is 80 bits. Using the feedback method of directly indicating the precoding matrix of each subband in the first precoding matrix set using the second precoding indication information, assuming that the optional codeword set of multiple subbands to be fed back contains 16 codewords, it is necessary to feed back one first precoding matrix indication information and the second precoding indication information of 10 subbands. In this case, the first precoding indication information occupies 8 bits, and the second precoding indication information of each subband occupies 4 bits, requiring a total of 48 bits as feedback overhead. In this way, the hierarchical feedback structure (i.e., the feedback structure indicated by the first precoding indication information and the second precoding indication information) is used to reduce the number of bits required for each codeword index, effectively reducing the feedback overhead.

[0053] Furthermore, based on the technical solutions provided in this disclosure, the multiple subbands may include a first subband and a second subband, and the second precoding matrix indication information for the first subband is determined based on the second precoding matrix indication information for the second subband. This further reduces feedback overhead. For example, when 10 subbands are divided into first and second subband groups, each subband group contains 5 subbands, and the second subband in the second subband group directly selects a precoding matrix from the first precoding matrix set determined by the first precoding indication information. Furthermore, each second subband in the second subband group also determines a precoding matrix subset from the first precoding matrix set for selection by the first subband of the first subband group. If the number of codewords in each codeword subset is 4, then the second precoding indication information corresponding to each first subband in the first subband group only requires 2 bits. In this case, the first precoding matrix indication information requires 8 bits, the second precoding matrix indication information for all second subbands in the second subband group requires a total of 20 bits, and the second precoding matrix indication information for all second subbands in the second subband group requires a total of 20 bits. The second precoding matrix indication information for all first subbands in the first subband group requires a total of 10 bits. This means that the total feedback overhead for feeding back the precoding matrix indication information can be reduced to 38 bits, further reducing the feedback overhead. In addition, when a large number of subbands require feedback on channel information, the feedback overhead can be significantly reduced.

[0054] In some embodiments, a reference signal can be measured to obtain first channel state information, and then the obtained first channel state information is processed to obtain channel state information to be fed back, that is, the above-mentioned first precoding matrix indication information and the second precoding matrix indication information corresponding to each of the multiple subbands are obtained.

[0055] Exemplarily, channel estimation may be performed on the wireless channel based on the received reference signal to obtain the first channel state information.

[0056] In one example, the signal y′ can be expressed in the form of the following formula (2): y′=Wy Formula (2)

[0057] Wherein, W is the measurement matrix, y is the received reference signal, and y′ is the transformed signal obtained by applying the measurement matrix W to the received reference signal y.

[0058] W can be determined by using a channel estimation method based on minimum mean square error (MMSE) estimation, linear minimum mean square error (LMMSE) estimation, maximum likelihood (ML) estimation, subspace-based estimation, etc.

[0059] Furthermore, from the above formula (1), it can be seen that the received reference signal y includes channel H, and the channel H can be determined from y′ using the measurement matrix W, and then the above first channel state information can be obtained based on the determined channel H.

[0060] It should be noted that since the dimension of the channel H is related to the bandwidth and the dimensions of the transceiver array, as the bandwidth in the communication system increases and the size of the transceiver array expands, the dimension of the channel matrix also increases accordingly, resulting in a high overhead for directly feeding back the complete channel matrix. Therefore, to reduce feedback overhead and improve the real-time performance of the system, the channel state information (i.e., the first channel state information) can be represented in a specific manner for feedback, such as by compressing or reducing the dimensionality of the complete channel state information (i.e., the first channel state information).

[0061] For example, codebook-based precoding matrix indication information feedback is a viable channel state feedback method, in which each codeword in the codebook can represent a specific channel state, thereby compressing the amount of feedback information. This allows high-dimensional channel state information to be converted into low-dimensional transmittable data. This significantly reduces the amount of feedback data while ensuring a certain level of accuracy, thereby reducing transmission overhead. When feeding back channel information, it is not necessary to directly feed back the selected codeword. Instead, information indicating the selected codeword, i.e., precoding matrix indication information, is fed back. Generally, to reduce feedback overhead, precoding matrix indication information is divided into first precoding matrix indication information and second precoding matrix indication information. Sometimes, the first and second precoding matrix indication information correspond to broadband and narrowband indication information, respectively. Broadband indication information refers to information applicable to a wider frequency band, while narrowband indication information applies to a narrower bandwidth.

[0062] The acquired first channel state information is processed, such as compressed or dimensionally reduced, to obtain channel state information to be fed back, that is, the first precoding matrix indication information and the second precoding matrix indication information corresponding to each of the multiple subbands are obtained.

[0063] In some embodiments, the first precoding indication information may include first indication information and second indication information. The first indication information may be used to indicate the codeword index of the precoding matrix in the first precoding matrix set in the first direction, and the second indication information may be used to indicate the codeword index of the precoding matrix in the first precoding matrix set in the second direction. Exemplarily, the first precoding indication information may be represented as i1, and the second indication information may be represented as i 1,1 And the second indication information can be expressed as i 1,2 , the first precoding matrix set or codeword set can be indicated as:

[0064] Among them, the collection It consists of M1 rows and M2 columns of sub-codeword groups, W l,m Represents an element in the set, representing a sub-codeword group. l,m The subscripts l and m are the indexes of the subcodeword group in the codebook, K1, K2, M1, and M2 are preset parameters, and K1 and K2 are used to determine the reference subcodeword group. In the collection The offset in M1 and M2 determines the set The number of rows and columns of the sub-codeword group. For example, when K1 and K2 are both set to 0, the reference sub-codeword group Located in the collection in the upper left corner.

[0065] In some embodiments, a sub-codeword group W l,m It can be used to represent a set of codewords with the same beam direction. In this case, the codewords in the codeword group can be used to determine the beam direction when configuring the precoding of the MIMO array according to the indexes l and m. It can be used to indicate the optional beam range of the subband during feedback.

[0066] In one example, when K1 and K2 are both set to 0, the set Reference subcodeword group in At this time, the relationship between the first precoding indication information, the second precoding indication information, and the codeword index may be as shown in the following Table 1:

[0067] Table 1

[0068] The first precoding indication information i1 includes the first indication information i 1,1 And the second indication information i 1,2 , i2 represents the second precoding indication information. N1, N2, O1, O2 are preset values, and the values ​​of N1, N2, O1, O2 can be determined by receiving configuration signaling or can be preset based on a specified rule. 1,1 The value range of includes 0, 1, ..., N1O1-M1 shown in the first column of Table 1, i 1,2 The value range of includes 0, 1, ..., N2O2-M2 shown in the second column of Table 1. In some examples, i 1,2 and M2 can be set to 0, in which case the number of sub-codeword groups is M1. In addition, based on Table 1, the bit length of the second precoding indication information can be expressed as in Indicates rounding X upwards.

[0069] In one example, the codewords in the codebook can be expressed as follows:

[0070] in,

[0071] The codeword index {l, m, n} may be determined according to the precoding matrix indication information {i1, i2}.

[0072] Exemplarily, based on the first precoding matrix indication information i1, the range of the optional sub-codeword group, that is, the first precoding matrix set, can be determined. Based on the second precoding matrix indication information i2 of the subband, the position of the selected precoding matrix of the subband in the first precoding matrix set can be determined. For example, when M1=2, M2=2, K1=0, K2=0, the value of i1 is {i 1,1 =8,i 1,2 =6}, then the optional sub-code word group can be determined to be {W 8,6 ,W 8,7 ,W 9,6 ,W 9,7}. When the value range of n is 0 to 3, each sub-codeword group contains 4 codewords. In this case, the value range of i2 can be 0 to 15. In this way, the codeword indicated by the precoding indication information {i1, i2} can be determined according to the value of i2. For example, {i 1,1 =8,i 1,2 =6, i2=6} The determined codeword is W 9,6,1 .

[0073] In some embodiments, the plurality of subbands may include a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined according to the second precoding matrix indication information of the second subband.

[0074] In some embodiments, the length of the second precoding matrix indication information of the first subband is smaller than the length of the second precoding matrix indication information of the second subband.

[0075] In this way, based on the hierarchical feedback structure consisting of the first precoding indication information and the second precoding indication information, the second precoding indication information for a portion of subbands can be determined based on the second precoding indication information for another portion of subbands. This can reduce the length of the second precoding indication information for a portion of subbands (i.e., the second subbands), further reducing feedback overhead.

[0076] It should be noted that, as shown in Table 1 above, the second precoding indication information for each subband can be fed back independently, meaning that there is no correlation between the second precoding indication information for different subbands. However, due to frequency domain correlation in actual communication channels, adjacent subbands generally have similarities, and some channel parameters vary slowly across the frequency band. Therefore, the channel parameters of different subbands may have a certain degree of correlation. Therefore, the technical solution of the present disclosure allows the second precoding indication information for some subbands to be determined based on the second precoding indication information for other subbands.

[0077] In some embodiments, the second precoding matrix indication corresponding to the second subband is determined according to a channel measurement result.

[0078] In some embodiments, the second precoding matrix indication information for the second subband is used to determine the second precoding matrix set for the first subband, and the second precoding matrix indication information for the first subband is used to indicate the precoding matrix for the first subband from the second precoding matrix set. The second precoding matrix set is a subset of the first precoding matrix set.

[0079] In some embodiments, the indices of the precoding matrices in the second precoding matrix set are at least partially identical to or adjacent to the indices of the precoding matrices corresponding to the second subband.

[0080] In one example, the selectable codeword set for the first subband may be determined by the codeword selected for the second subband, as shown in Table 2:

[0081] Table 2

[0082] The optional codeword set for the pth subband is composed of the codewords selected for the p-1th subband. Determine, that is, the second precoding matrix indication information i of the p-th subband 2,p The value range of can be determined by the second precoding indication information i of the p-1th subband 2,p-1 That is, the Pth sub-band is the first sub-band, and the P-1th sub-band is the second sub-band.

[0083] Thus, according to the second precoding matrix indication information i of the second subband 2,p-1 The second precoding matrix set, i.e., the second precoding matrix indication information i of the first subband, can be determined. 2,p In this case, each element in the value range may be assigned an identifier or index, for example, each element may be numbered, so that the second precoding matrix information of the first word band may indicate the number, without indicating the complete index information of the precoding matrix of the first word band. The operator % in Table 2 represents a remainder operation. For example, i 2,p-1 = 0, the second precoding matrix indication information of the p-th subband can be configured as i 2,p =i 2,p -1+1, which is i 2,p is 1.

[0084] It should be noted that the collection When there are many codewords in the set, all subbands are directly fed back based on the set The precoding matrix information will require a large feedback overhead. Taking Table 2 as an example, the i provided in Table 2 2,p The range of optional codeword numbers only requires a maximum of 4 bits. When the codeword in is greater than 16, the number in Table 2 is used as the precoding matrix information of the first subband, and the required feedback overhead is smaller. Therefore, the feedback overhead can be compressed based on this method.

[0085] In some embodiments, the first subband and the second subband are adjacent. As shown in Table 2, the p-th subband is adjacent to the p-1-th subband, and the value range of the second precoding matrix indication information of the p-th subband can be determined by the second precoding indication information of the p-1-th subband.

[0086] In some embodiments, the indices of the precoding matrices in the second precoding matrix set are at least partially identical or adjacent to the indices of the precoding matrices corresponding to the second subband. As shown in Table 2, the codewords configured for the first subband and the second subband can have the same beam direction and different polarization phase states, so that the index used to represent the beam direction of the precoding matrix of the first subband can be the same as the index used to represent the beam direction of the precoding matrix of the second subband. In this way, when there are many optional polarization states indicated in the first precoding matrix set, the feedback overhead of the second precoding matrix indication information for the first subband can be greatly reduced.

[0087] In another example, the correspondence between the optional codeword set of the first sub-band and the selected codeword of the second sub-band is shown in Table 3:

[0088] Table 3

[0089] As shown in Table 3, the second precoding matrix indication information i of the p-th subband 2,p The value range of can be determined by the second precoding indication information i of the p-1th subband 2,p-1 That is, the Pth subband is the first subband, and the P-1th subband is the second subband. Thus, according to the second precoding matrix indication information i of the second subband 2,p-1 The second precoding matrix set, i.e., the second precoding matrix indication information i of the first subband, can be determined. 2,p At this time, each element in the value range can be configured with an identifier or index, for example, each element is numbered, so that the second precoding matrix information of the first word band can indicate the number, without indicating the complete index information of the precoding matrix of the first word band.

[0090] Furthermore, based on Table 3, the codewords configured for the first and second subbands can share the same phase state, so the index used to represent the polarization state in the precoding matrix for the first subband can be the same as the index used to represent the polarization state in the precoding matrix for the second subband. This significantly reduces the feedback overhead of the second precoding matrix indication information for the first subband when the first precoding matrix set indicates a large number of optional beam directions.

[0091] In some embodiments, the second precoding matrix indication information i of the first subband determined in Table 3 is 2,p The set of optional codewords can exceed the set In this case, no additional feedback overhead is added, and a more appropriate codeword can be selected for the subband during the feedback process.

[0092] In another example, the value range of the second precoding matrix indication information of the first subband may be determined by the value of the second precoding matrix indication information of the second subband, as shown in Table 4:

[0093] Table 4

[0094] As shown in Table 4, the second precoding matrix indication information i of the p-th subband 2,p The value range of can be determined by the second precoding indication information i of the p-1th subband 2,p-1 That is, the Pth subband is the first subband, and the P-1th subband is the second subband. Thus, according to the second precoding matrix indication information i of the second subband 2,p-1 The second precoding matrix set, i.e., the second precoding matrix indication information i of the first subband, can be determined. 2,p At this time, each element in the value range can be configured with an identifier or index, for example, each element is numbered, so that the second precoding matrix information of the first word band can indicate the number, without indicating the complete index information of the precoding matrix of the first word band.

[0095] In addition, based on the example shown in Table 4, the second precoding matrix indication information i of the first subband is 2,p The set of optional code words in the set As shown in Table 4, when i 2,p-1 Corresponding set When the codeword of the edge area is 2,p The range of selectable codewords becomes smaller.

[0096] In some embodiments, the center frequency of the first sub-band may be higher than the center frequency of the second sub-band, or the center frequency of the first sub-band may be lower than the center frequency of the second sub-band.

[0097] In some embodiments, the second precoding matrix indication information of one or more first subbands is determined based on the second precoding matrix indication information of the same second subband.

[0098] Exemplarily, the value range of the second precoding matrix indication information for the p-th subband can be determined by the second precoding matrix indication information for the p-1th and p+1th subbands. That is, based on the second precoding matrix indication information for the p-1th and p+1th subbands, a second precoding matrix set can be determined, and then the optional codewords in the second precoding matrix set can be numbered. Then, based on the selected codeword for the p-th subband in the second precoding matrix set, a corresponding number is determined as the second precoding matrix indication information for the subband.

[0099] In some embodiments, the plurality of subbands may be divided into a first subband group and a second subband group, the first subband belonging to the first subband group, and the second subband belonging to the second subband group.

[0100] That is, the precoding matrix indication information for the subband in the first subband group may be determined based on the precoding matrix indication information for the subband in the second subband group. In some embodiments, the length of the second precoding matrix indication information for the subband in the first subband group is less than the length of the second precoding matrix indication information for the subband in the second subband group.

[0101] It should be noted that the second precoding matrix indication information for the subbands in the first subband group can be understood as being obtained after compression. The mapping relationship between the second precoding matrix indication information for the subbands in the first subband group and the second precoding matrix indication information for the subbands in the second subband group and the codewords in the codebook is different. Therefore, the second precoding matrix indication information for the subbands in the first subband group relies on the second precoding matrix indication information for the subbands in the second subband group to determine the codewords it indicates. Furthermore, in practical applications, the second precoding matrix indication information for the subbands in the first subband group can also be labeled as another type of indication information, such as the third precoding matrix indication information, denoted as i3.

[0102] In some embodiments, the subbands in the first subband group are adjacent in the frequency domain.

[0103] In some embodiments, the first subband group includes subbands selected from a reference subband according to a preset frequency domain interval among the multiple subbands.

[0104] In one example, multiple subbands requiring feedback can be sorted according to their center frequencies, and the sorted subbands can be numbered sequentially starting from 0. Furthermore, odd-numbered subbands can be assigned to a first subband group, and even-numbered subbands can be assigned to a second subband group. Consequently, subbands in the second subband group can directly feedback second precoding matrix indication information determined based on channel measurement results. Furthermore, subbands in the first subband group can determine their second precoding matrix indication information based on at least one adjacent second subband in the second subband group.

[0105] For example, a subband in the first subband group is numbered 2p+1, and the second precoding matrix indication information of the subband can be determined based on the second precoding matrix indication information numbered 2p in the second subband group.

[0106] In another example, multiple subbands requiring feedback can be sorted according to their center frequencies, and the sorted subbands can be numbered sequentially starting from 0. Furthermore, subbands whose numbers are divisible by 3 are assigned to the second subband group and numbered, while the remaining subbands are assigned to the first subband group. Thus, subbands in the second subband group can directly feedback second precoding matrix indication information determined based on channel measurement results, and subbands in the first subband group can determine the second precoding matrix indication information for the subband based on at least one second subband adjacent to the subband in the second subband group.

[0107] For example, a subband in the first subband group is numbered 3p+q, and the second precoding matrix indication information of the subband can be determined based on the second precoding matrix indication information numbered 3p in the second subband group, where q=1,2.

[0108] It should be understood that the above description is merely an exemplary illustration of the division of the first subband group and the second subband group. The first subband group and the second subband group may also include other possible division methods. For example, the first subband group may consist of subbands whose numbers are divisible by R, and the remaining subbands constitute the second subband group, where R is a preset positive integer. This disclosure is not limited to this.

[0109] In some embodiments, a first precoding matrix set may be determined from a preset codebook, denoted as set S1, and the set S1 may be indicated by first precoding matrix indication information.

[0110] Furthermore, a portion of the multiple subbands to be fed back (i.e., the aforementioned second subbands) can select corresponding precoding matrices from the set S1. Furthermore, the second precoding matrix indication information corresponding to each second subband can be used to indicate that the corresponding precoding matrix for each subband is selected from the set S1. In some examples, the length of the second precoding matrix indication information for the second subband can be determined based on the number of codewords in the set S1.

[0111] Based on the precoding matrices corresponding to the second subbands, a set of second precoding matrices corresponding to each second subband can be determined in set S1, which is recorded as set S2. It should be understood that each set S2 is a subset of set S1.

[0112] Another portion of the subbands (i.e., the first subbands described above) among the multiple subbands to be fed back can select a precoding matrix from the set S2 corresponding to each first subband. Furthermore, the second precoding matrix indication information corresponding to each first subband can be used to indicate the precoding matrix selected from the corresponding set S2 for each subband. In some examples, the length of the second precoding matrix indication information for a first subband can be determined based on the number of codewords in the set S2 corresponding to the first subband.

[0113] S103: Send channel state information.

[0114] Exemplarily, the transmitting end may transmit the determined channel state information, where the channel state information includes the first precoding matrix indication information and the second precoding matrix indication information for each of the multiple subbands. Furthermore, the multiple subbands may include a first subband and a second subband, and the second precoding matrix indication information for the first subband is determined based on the second precoding matrix indication information for the second subband. The precoding matrix corresponding to each subband may be determined based on the first precoding matrix indication information and the second precoding matrix indication information for each of the multiple subbands. Accordingly, upon receiving the channel state information, the receiving end may determine an appropriate precoding matrix configuration based on the channel state information.

[0115] Based on the technical solution provided by the present disclosure, on the basis of using a hierarchical feedback structure (i.e., a feedback structure jointly indicated by first and second precoding indication information) for channel state information feedback, the subband to be fed back is further divided into a first subband and a second subband. Based on the correlation between the second precoding matrix indication information of the first subband and the second subband, the second precoding matrix indication information of the first subband can be determined based on the second precoding matrix indication information of the second subband. In other words, the second precoding indication information of the second subband and the second precoding indication information of the first subband can jointly indicate the precoding matrix corresponding to each first subband. In this way, while ensuring the accuracy of the indication of the precoding matrix corresponding to each first subband, the precoding indication information of the first subband is also compressed, thereby reducing the feedback overhead of the channel state information.

[0116] The above mainly introduces the solution provided by the present disclosure from the perspective of the interaction between various devices or nodes. It is understandable that, in order to realize the above functions, each device or node includes a hardware structure and / or software module 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 disclosed herein, 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 the form of hardware or computer software driving hardware 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 invention.

[0117] Figure 3 is a schematic diagram showing the composition of a communication device provided by an embodiment of the present disclosure. As shown in Figure 3, the communication device 300 includes a receiving module 301, a determining module 302, and a sending module 303;

[0118] Receiving module 301, configured to receive a reference signal;

[0119] a determination module 302, configured to determine channel state information based on a reference signal, where the channel state information includes first precoding matrix indication information and second precoding matrix indication information corresponding to each of a plurality of subbands; wherein the plurality of subbands includes a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined based on the second precoding matrix indication information of the second subband;

[0120] The sending module 303 is configured to send channel state information.

[0121] In some embodiments, the first precoding matrix indication information is used to indicate a first precoding matrix set, and the second precoding matrix indication information is used to indicate a precoding matrix of a corresponding subband from the first precoding matrix set.

[0122] In some embodiments, the length of the second precoding matrix indication information of the first subband is smaller than the length of the second precoding matrix indication information of the second subband.

[0123] In some embodiments, the second precoding matrix indication information of the second subband is used to determine the second precoding matrix set of the first subband, where the second precoding matrix set is a subset of the first precoding matrix set; the second precoding matrix indication information of the first subband is used to indicate the precoding matrix of the first subband from the second precoding matrix set.

[0124] In some embodiments, the indices of the precoding matrices in the second precoding matrix set are at least partially identical to or adjacent to the indices of the precoding matrices corresponding to the second subband.

[0125] In some embodiments, the first sub-band and the second sub-band are adjacent.

[0126] In some embodiments, the second precoding indication information of one first subband is determined based on the precoding indication information of at least one second subband.

[0127] In some embodiments, the plurality of subbands are divided into a first subband group and a second subband group, the first subband belongs to the first subband group, and the second subband belongs to the second subband group.

[0128] In some embodiments, the subbands in the first subband group are adjacent in the frequency domain.

[0129] In some embodiments, the first subband group includes subbands selected from a reference subband according to a preset frequency domain interval among the multiple subbands.

[0130] In some embodiments, the second precoding matrix indication information corresponding to the second subband is determined according to a channel measurement result.

[0131] For a more detailed description of the above-mentioned receiving module 301, determining module 302 and sending module 303, as well as a more detailed description of each technical feature therein and a description of the beneficial effects, etc., please refer to the above-mentioned corresponding method embodiment part and will not be repeated here.

[0132] It should be noted that the modules in FIG3 may also be referred to as units. For example, the sending module may be referred to as a sending unit. In addition, in the embodiment shown in FIG3 , the names of the modules may not be those shown in the figure. For example, the sending module may be referred to as a communication module, and the receiving module may be referred to as a communication module.

[0133] If the various units or modules in Figure 3 are implemented in the form of software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present disclosure is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the various embodiments of the present disclosure. The storage medium for storing computer software products includes various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0134] In the case of implementing the functions of the above-mentioned integrated modules in hardware, an embodiment of the present disclosure provides a schematic structural diagram of a communication device, which may be the above-mentioned communication device 300. As shown in Figure 4, the communication device 400 includes: a processor 402, a communication interface 403, and a bus 404. Optionally, the communication device 400 may also include a memory 401.

[0135] Processor 402 may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. Processor 402 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. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. Processor 402 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, or a combination of a DSP and a microprocessor.

[0136] The communication interface 403 is used to connect to other devices via a communication network, such as Ethernet, wireless access network, wireless local area network (WLAN), etc.

[0137] The memory 401 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 information and instructions, or 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.

[0138] As a possible implementation, memory 401 may exist independently of processor 402. Memory 401 may be connected to processor 402 via bus 404 to store instructions or program codes. When processor 402 calls and executes the instructions or program codes stored in memory 401, the method provided in the embodiments of the present disclosure can be implemented.

[0139] In another possible implementation, the memory 401 may also be integrated with the processor 402 .

[0140] Bus 404 can be an Extended Industry Standard Architecture (EISA) bus, etc. Bus 404 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, FIG4 shows only one thick line, but this does not mean that there is only one bus or only one type of bus.

[0141] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, that is, the internal structure of the equipment or device is divided into different functional modules to complete all or part of the functions described above.

[0142] The embodiments of the present disclosure also provide a computer-readable storage medium. All or part of the processes in the above-mentioned method embodiments can be completed by computer instructions to instruct relevant hardware, and the program can be stored in the above-mentioned computer-readable storage medium. When the program is executed, it can include the processes of the above-mentioned method embodiments. The computer-readable storage medium can be the memory of any of the above-mentioned embodiments. The above-mentioned computer-readable storage medium can also be an external storage device of the above-mentioned device or apparatus, such as a plug-in hard disk, a smart memory card (smart media card, SMC), a secure digital (secure digital, SD) card, a flash card (flash card), etc. equipped on the above-mentioned device or apparatus. Furthermore, the above-mentioned computer-readable storage medium can also include both the internal storage unit of the above-mentioned device or apparatus and an external storage device. The above-mentioned computer-readable storage medium is used to store the above-mentioned computer program and other programs and data required by the above-mentioned device or apparatus. The above-mentioned computer-readable storage medium can also be used to temporarily store data that has been output or is to be output.

[0143] The embodiments of the present disclosure further provide a computer program product, which includes a computer program. When the computer program product is run on a computer, the computer is enabled to execute any one of the methods provided in the above embodiments.

[0144] Although the present disclosure is described herein in conjunction with various embodiments, in the process of implementing the disclosure for which protection is sought, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple components. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0145] Although the present disclosure has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present disclosure. Accordingly, this specification and the drawings are merely illustrative of the present disclosure as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present disclosure. Obviously, those skilled in the art may make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, the present disclosure is intended to encompass such modifications and variations if they fall within the scope of the claims of the present disclosure and their equivalents.

[0146] 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 method for feeding back channel state information, characterized in that: The method comprises: receiving a reference signal; determining, based on the reference signal, channel state information, the channel state information comprising first precoding matrix indication information and second precoding matrix indication information corresponding to each of a plurality of subbands; wherein the plurality of subbands comprises a first subband and a second subband, and the second precoding matrix indication information of the first subband is determined based on the second precoding matrix indication information of the second subband; The channel state information is sent.

2. The method according to claim 1, characterized in that The first precoding matrix indication information is used to indicate a first precoding matrix set, and the second precoding matrix indication information is used to indicate a precoding matrix of a corresponding subband from the first precoding matrix set.

3. The method according to claim 1, characterized in that The length of the second precoding matrix indication information of the first subband is smaller than the length of the second precoding matrix indication information of the second subband.

4. The method according to claim 2, characterized in that The second precoding matrix indication information of the second subband is used to determine a second precoding matrix set for the first subband, where the second precoding matrix set is a subset of the first precoding matrix set; the second precoding matrix indication information of the first subband is used to indicate a precoding matrix for the first subband from the second precoding matrix set.

5. The method according to claim 4, characterized in that The indexes of the precoding matrices in the second precoding matrix set are at least partially identical to or adjacent to the indexes of the precoding matrices corresponding to the second subband.

6. The method according to claim 1, characterized in that The first sub-band and the second sub-band are adjacent.

7. The method according to claim 1, characterized in that The second precoding indication information of one first subband is determined based on the precoding indication information of at least one second subband.

8. The method according to claim 1, characterized in that The plurality of subbands are divided into a first subband group and a second subband group, the first subband belongs to the first subband group, and the second subband belongs to the second subband group.

9. The method according to claim 8, characterized in that The subbands in the first subband group are adjacent in the frequency domain.

10. The method according to claim 8, characterized in that The first subband group includes subbands selected from the multiple subbands starting from a reference subband according to a preset frequency domain interval.

11. The method according to claim 1, wherein The second precoding matrix indication information corresponding to the second subband is determined according to a channel measurement result.

12. A communication device, characterized in that: include: memory and processor; Memory and processor coupling; 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 11 is performed.

13. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 11.

14. A computer program product, characterized in that The computer program product comprises a computer program, which, when run on a computer, causes the computer to perform the method according to any one of claims 1 to 11.

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