WO2024067116A1

WO2024067116A1 - Multi-band codebook design method and communication apparatus

Info

Publication number: WO2024067116A1
Application number: PCT/CN2023/118721
Authority: WO
Inventors: 张笛笛; 王潇涵; 丁梦颖; 金黄平; 彭金磷
Original assignee: 华为技术有限公司
Priority date: 2022-09-29
Filing date: 2023-09-14
Publication date: 2024-04-04
Also published as: CN117792448A

Abstract

The present application provides a multi-band codebook design method and an apparatus. The method comprises: a terminal device determines a space-frequency joint feature common substrate according to a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, the first frequency band and the second frequency band are both communication frequency bands of the terminal device and a network device, and the space-frequency joint feature common substrate is used for determining a space-frequency joint feature substrate of the first frequency band and a space-frequency joint feature substrate of the second frequency band; and the terminal device sends information of the space-frequency joint feature common substrate to the network device. In this method, the terminal device performs joint feature substrate design on different frequency bands, and the terminal device only needs to feed back one common substrate for two frequency bands, thereby reducing the overhead of the terminal device feeding back CSI.

Description

A method for designing a multi-band codebook and a communication device

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 29, 2022, with application number 202211204330.3 and application name “A method and communication device for multi-band codebook design”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of communication technology, and more specifically, to a method for designing a multi-band codebook and a communication device.

Background technique

Channel state information (CSI) is information reported by the terminal to the base station in a wireless communication system to describe the channel properties of the communication link. The base station can send a channel-state information reference signal (CSI-RS) to the terminal. The terminal performs downlink channel measurement based on the CSI-RS sent by the base station to obtain the CSI of the downlink channel and reports the CSI to the base station. The base station schedules downlink data based on the CSI.

The massive multiple-input multiple-output (massive MIMO) system can significantly improve the spectrum efficiency through large-scale antennas, and the accuracy of the CSI obtained by the base station largely determines the performance of massive MIMO. Therefore, the characteristic information of the channel is usually represented by a codebook. When representing the channel characteristic information through a codebook, it is necessary to approach the original channel characteristics as much as possible under the allowable overhead to make the channel quantization more accurate.

In order to further improve the capacity of the system, multi-frequency fusion technology came into being. The terminal supports multiple frequency bands at the same time, and the base station can send downlink data to the terminal through multiple frequency bands. Since the channels of different frequency bands are different, in order to support multiple frequency bands to send downlink data to the same terminal, the base station needs to obtain the CSI of each frequency band. In the current technology, the terminal needs to design the codebook separately for different frequency bands and report the CSI separately. As the number of frequency bands supported by the terminal increases, the reporting overhead of the terminal is also increasing exponentially. At this time, how to reduce the reporting overhead of the terminal has become an urgent problem to be solved.

Summary of the invention

The present application provides a method and a communication device for designing a multi-band codebook, which can reduce the overhead of reporting CSI by a terminal.

In a first aspect, a method for designing a multi-band codebook is provided. The method may be executed by a terminal device, or may be executed by a chip or circuit configured in the terminal device, and the present application does not limit this.

The method includes: a terminal device determines a space-frequency joint characteristic common basis according to a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, and the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, the first frequency band and the second frequency band are both communication frequency bands between the terminal device and a network device, and the space-frequency joint characteristic common basis is used to determine the space-frequency joint characteristic basis of the first frequency band and the space-frequency joint characteristic basis of the second frequency band; and the terminal device sends information indicating the space-frequency joint characteristic common basis to the network device.

In the above technical solution, the terminal device designs a joint feature basis for different frequency bands. The terminal device only needs to feedback one common basis for two frequency bands, thereby reducing the overhead of the terminal device in feedbacking CSI.

In certain implementations of the first aspect, the terminal device determines a space-frequency joint characteristic common basis based on a first channel matrix and a second channel matrix, including: the terminal device determines a first space-frequency joint channel covariance matrix based on the first channel matrix, and determines a second space-frequency joint channel covariance matrix based on the second channel matrix; the terminal device determines a space-frequency joint characteristic common basis based on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix.

In the above technical solution, the terminal device designs a joint feature basis based on the corresponding space-frequency joint channel covariance matrix of the two frequency bands. The terminal device only needs to feedback one common basis for the two frequency bands, thereby reducing the overhead of the terminal device to feedback CSI.

In certain implementations of the first aspect, the number of antenna ports _Nt1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports _Nt2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is greater than or equal to the number of subbands B2 corresponding to the second frequency band. The corresponding number of subbands is B2; the terminal device determines the space-frequency joint feature common basis according to the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix, including: the terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, and determines the space-frequency joint channel statistical covariance matrix according to the summed matrix; the terminal device determines a singular matrix according to the space-frequency joint channel statistical covariance matrix, and selects the first L columns of the singular matrix as the space-frequency joint feature common basis, wherein L is less than or equal to the smaller value of B1*N _t1 /2 and B2*N _t2 /2.

The space-frequency joint channel statistical covariance matrix obtained in the above scheme can contain the information of each subband of the first frequency band and the second frequency band, that is, the space-frequency joint characteristic common basis can contain the information of each subband of the first frequency band and the second frequency band, thereby realizing the joint characteristic basis design for the two frequency bands. The terminal device only needs to feedback one common basis for the two frequency bands, thereby reducing the overhead of the terminal device to feedback CSI.

In the above technical solution, the terminal device only needs to perform a singular value decomposition on the acquired space-frequency joint channel statistical covariance matrix to obtain the space-frequency joint feature common basis, which can reduce the calculation complexity of the terminal device.

In certain implementations of the first aspect, N _t1 /2 is equal to N _t2 /2, B1 is greater than B2, the first rule indicates information of B2 subbands in the B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and the terminal device performs positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, including: aligning and adding the N _t2 /2 rows corresponding to each subband in the B2 subbands in the second space-frequency joint channel covariance matrix in sequence with the N _t1 /2 rows corresponding to each subband in the B2 subbands in the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix.

In certain implementations of the first aspect, N _t1 /2 is greater than N _t2 /2, and B1 is equal to B2, the first rule indicates that row information and column information of 0 elements are added to each square matrix in the square matrix with B2*B2 rows being N _t2 /2 and columns being N _t2 /2 included in the second covariance matrix, and the terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, including: determining a third space-frequency joint channel covariance matrix, the third space-frequency joint channel covariance matrix being a matrix generated by adding N t1 /2-N _t2 /2 rows and N _t1 /2-N t2 /2 columns of 0 elements to each square matrix in the square matrix with B2*B2 rows being N _t2 /2 and columns being N _{t2 /2 included in the second covariance matrix according to the row information and column information indicated by the first rule; and adding N t1} _/ 2-N _t2 _/ 2 corresponding to each of the B2 subbands in the third space-frequency joint channel covariance matrix. The N _t1 /2 rows corresponding to each subband in the B1 subbands in the first space-frequency joint channel covariance matrix are aligned and added in sequence.

In certain implementations of the first aspect, N _t1 /2 is greater than N _t2 /2, and B1 is greater than B2, the first rule indicates information of B2 subbands in the B1 subbands of the first frequency band used to calculate the statistical covariance matrix of the space-frequency joint channel, and row information and column information of 0 elements are added to each square matrix in the second covariance matrix with B2*B2 rows as N _t2 /2 and N _t2 /2 columns, and the terminal device performs bitwise summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, including: determining a fourth space-frequency joint channel covariance matrix, the fourth space-frequency joint channel covariance matrix is to add N t1 /2-N t2 /2 rows and N _t1 /2-N t2 /2 rows to each square matrix in the second covariance matrix with _B2 *B2 rows as N _t2 /2 _and N _t2 /2 columns according to the row information and column information indicated by the first rule _. /2 columns with 0 elements; align and add the N _t1 /2 rows corresponding to each of the B2 subbands in the fourth space-frequency joint channel covariance matrix and the N _t1 /2 rows corresponding to each of the B2 subbands in the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix in sequence.

In certain implementations of the first aspect, N _t1 /2 is equal to N _t2 /2, and B1 is equal to B2, and the terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, including: aligning and adding the N _t1 /2 rows corresponding to each subband in the B2 subbands in the second space-frequency joint channel covariance matrix in sequence with the N _t2 /2 rows corresponding to each subband in the B1 subbands in the first space-frequency joint channel covariance matrix.

In certain implementations of the first aspect, the method also includes: the terminal device receives first indication information sent from the network device, the first indication information includes a first rule, and the first indication information is used to instruct the terminal device to perform a positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.

In certain implementations of the first aspect, the method also includes: the terminal device sends second indication information to the network device, the second indication information includes a first rule, and the second indication information instructs the network device to intercept the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.

In certain implementations of the first aspect, the information used to indicate the common basis of the space-frequency joint feature includes: The index number of the discrete Fourier transform basis vector and the projection coefficient of the common basis of the space-frequency joint feature on the discrete Fourier transform basis vector.

In a second aspect, a method for designing a multi-band codebook is provided. The method may be executed by a network device, or may be executed by a chip or circuit configured in the network device, and the present application does not limit this.

The method includes: a network device receives information indicating a common basis of space-frequency joint characteristics from a terminal device, the common basis of space-frequency joint characteristics is determined by the terminal device based on a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, and both the first frequency band and the second frequency band are communication frequency bands between the network device and the terminal device; the network device determines the space-frequency joint characteristic basis of the first frequency band and the space-frequency joint characteristic basis of the second frequency band based on the information indicating the common basis of space-frequency joint characteristics.

For the beneficial effects of the second aspect, please refer to the description of the first aspect and will not be repeated here.

In certain implementations of the second aspect, the space-frequency joint feature common basis is determined based on a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix, the first space-frequency joint channel covariance matrix is determined based on a first channel matrix, and the second space-frequency joint channel covariance matrix is determined based on a second space-frequency joint channel covariance matrix.

In the above technical solution, the space-frequency joint feature common basis is obtained by designing a joint feature basis based on the corresponding space-frequency joint channel covariance matrices of the two frequency bands, thereby reducing the overhead of feedback CSI.

In certain implementations of the second aspect, the number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is greater than or equal to the number of subbands B2 corresponding to the second frequency band, the space-frequency joint feature common basis is composed of the first L columns of a singular matrix, the singular matrix is obtained by performing singular value decomposition on the space-frequency joint channel statistical covariance matrix, the space-frequency joint channel statistical covariance matrix is obtained by performing positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule, and filtering and updating the summed matrix, wherein L is less than or equal to B1*N _t1 /2 and B2*N _t2 /2; the network device determines the space-frequency joint feature basis of the first frequency band and the space-frequency joint feature basis of the second frequency band according to the space-frequency joint feature common basis, including: the network device determines the space-frequency joint feature common basis as the space-frequency joint feature basis of the first frequency band; the network device selects elements of the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band.

The space-frequency joint channel statistical covariance matrix obtained in the above scheme can contain the information of each subband of the first frequency band and the second frequency band, that is, the space-frequency joint characteristic common basis can contain the information of each subband of the first frequency band and the second frequency band, so that the joint characteristic basis design of the two frequency bands can be realized, thereby reducing the overhead of feedback CSI.

In certain implementations of the second aspect, N _t1 /2 is equal to N _t2 /2, B1 is greater than B2, the first rule indicates information of B2 subbands in the B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and the network device selects elements of the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including: determining B2*N _t2 /2 rows of the space-frequency joint feature common basis as the space-frequency joint feature basis of the second frequency band, wherein B2*N _t2 /2 rows are the N _t1 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the first frequency band indicated by the first rule.

In the above technical scheme, when a joint characteristic basis is designed for different frequency bands, two frequency bands share one characteristic basis. If the bandwidths corresponding to the two frequency bands are different, the characteristic basis of the frequency band with a smaller number of sub-bands (i.e., the second frequency band) can be obtained by truncating the characteristic basis of the frequency band with a larger number of sub-bands (i.e., the first frequency band).

In certain implementations of the second aspect, N _t1 /2 is greater than N _t2 /2, and B1 is equal to B2, the first rule indicates that the second covariance matrix contains B2*B2 rows of N _t2 /2 and the columns are N _t2 /2, and row information and column information of 0 elements are added to each square matrix in the square matrix, and the network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including: extracting elements in B2*N _t2 /2 rows in the space-frequency joint feature common basis, where B2*N _t2 /2 rows correspond to N _t2 /2 rows in the space-frequency joint channel statistical covariance matrix for each subband in the B2 subbands of the second frequency band in the third space-frequency joint channel covariance matrix, wherein the third space-frequency joint channel covariance matrix is the square matrix with B2*B2 rows of N _t2 /2 and the columns are N t2 /2 in the second covariance matrix and N _t1 /2-N _t2 /2 elements are added according to the row information and column information indicated by the first rule. The matrix generated after N _t2 /2 rows and N _t1 /2-N _t2 /2 columns are filled with 0 elements, and the N _t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix do not include the rows where the 0 elements added in the N _t1 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix are located; the extracted elements are spliced to obtain the space-frequency joint feature basis of the second frequency band.

In the above technical solution, when designing joint characteristic bases for different frequency bands, two frequency bands share a common characteristic base. When two frequency bands are measured, the number of antenna ports used is different. Then, the characteristic basis of the frequency band with fewer ports can be obtained by extracting the characteristic basis of the frequency band with more ports.

In certain implementations of the second aspect, N _t1 /2 is greater than N _t2 /2, and B1 is greater than B2, the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and the B2*B2 rows contained in the second covariance matrix are N _t2 /2, and the columns are row information and column information of adding 0 elements to each square matrix in the N _t2 /2 square matrix, and the network device selects elements of the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including: determining B2*N _t1 /2 rows of the space-frequency joint feature common basis as the third space-frequency joint feature basis, wherein B2*N _t1 /2 rows are the rows corresponding to the N _t1 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to the B2 subbands in the second frequency band in the fourth space-frequency joint channel covariance matrix, and the fourth space-frequency joint channel covariance matrix is the B2*B2 rows contained in the second space-frequency joint channel covariance matrix. _{A matrix is generated after each square matrix in the square matrix with N t2} _/ 2 columns adds N _t1 /2-N _t2 /2 rows and N _t1 /2-N _t2 /2 columns of 0 elements according to the row information and column information indicated by the first rule; the elements in the B2*N _t2 /2 rows in the third space-frequency joint feature common basis are extracted, and the B2*N _t2 /2 rows are the N t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix in the space-frequency joint channel statistical covariance matrix, and the N _t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix do not include the rows where the 0 elements added to the N _t1 /2 rows corresponding to each subband in the _B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix are located; the extracted elements are spliced to obtain the space-frequency joint feature basis of the second frequency band.

In certain implementations of the second aspect, N _t1 /2 is equal to N _t2 /2, and B1 is greater than B2, and the network device selects elements of the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including: the network device determines the space-frequency joint feature common basis as the space-frequency joint feature basis of the second frequency band.

In certain implementations of the second aspect, the method also includes: the network device sends first indication information to the terminal device, the first indication information includes a first rule, and the first indication information is used to instruct the terminal device to perform a positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.

In certain implementations of the second aspect, the method also includes: the network device receives second indication information sent from the terminal device, the second indication information includes a first rule, and the second indication information instructs the network device to process the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.

In certain implementations of the second aspect, the information indicating the space-frequency joint feature common basis includes: the index number of the discrete Fourier transform basis vector corresponding to the oversampling group and the projection coefficient of the space-frequency joint feature common basis on the discrete Fourier transform basis vector.

In a third aspect, a communication device is provided, which is used to execute the method provided in the first aspect. Specifically, the device may include a unit and/or module, such as a processing unit and/or a communication unit, for executing the method in the first aspect and any possible implementation of the first aspect.

In one implementation, the apparatus is a terminal device. When the apparatus is a terminal device, the communication unit may be a transceiver, or an input/output interface; the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input/output interface may be an input/output circuit.

In another implementation, the device is a chip, a chip system or a circuit used in a terminal device. When the device is a chip, a chip system or a circuit used in a terminal device, the communication unit may be an input/output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit on the chip, the chip system or the circuit; the processing unit may be at least one processor, a processing circuit or a logic circuit.

In a fourth aspect, a communication device is provided, which is used to execute the method provided in the second aspect. Specifically, the device may include a unit and/or module, such as a processing unit and/or a communication unit, for executing the method in the second aspect and any possible implementation of the second aspect.

In one implementation, the device is a network device. When the device is a network device, the communication unit may be a transceiver, or an input/output interface; the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input/output interface may be an input/output circuit.

In another implementation, the device is a chip, a chip system or a circuit used in a network device. When the device is a chip, a chip system or a circuit used in a terminal device, the communication unit may be an input/output interface, a connection interface or a circuit on the chip, the chip system or the circuit. port circuit, output circuit, input circuit, pin or related circuit, etc.; the processing unit may be at least one processor, processing circuit or logic circuit, etc.

In a fifth aspect, a communication device is provided, comprising: at least one processor, the at least one processor is coupled to at least one memory, the at least one memory is used to store computer programs or instructions, and the at least one processor is used to call and run the computer program or instructions from the at least one memory, so that the communication device executes the method in the first aspect and any possible implementation manner of the first aspect.

In one implementation, the apparatus is a terminal device.

In another implementation, the apparatus is a chip, a chip system or a circuit used in a terminal device.

In a sixth aspect, a communication device is provided, comprising: at least one processor, the at least one processor is coupled to at least one memory, the at least one memory is used to store computer programs or instructions, and the at least one processor is used to call and run the computer program or instructions from the at least one memory, so that the communication device executes the method in the second aspect and any possible implementation of the second aspect.

In one implementation, the apparatus is a network device.

In another implementation, the apparatus is a chip, a chip system, or a circuit used in a network device.

In a seventh aspect, a processor is provided for executing the methods provided in the above aspects.

For the operations such as sending and acquiring/receiving involved in the processor, unless otherwise specified, or unless they conflict with their actual function or internal logic in the relevant description, they can be understood as operations such as processor output, reception, input, etc., or as sending and receiving operations performed by the radio frequency circuit and antenna, and this application does not limit this.

In an eighth aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, wherein the program code includes a method for executing the above-mentioned first aspect and any possible implementation manner of the first aspect.

In a ninth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the method in the second aspect and any possible implementation of the second aspect.

In a tenth aspect, a chip is provided, the chip including a processor and a communication interface, the processor reads instructions stored in a memory through the communication interface, and executes the method in the above-mentioned first aspect and any possible implementation method of the first aspect.

Optionally, as an implementation method, the chip also includes a memory, in which a computer program or instructions are stored, and the processor is used to execute the computer program or instructions stored in the memory. When the computer program or instructions are executed, the processor is used to execute the method in the above-mentioned first aspect and any possible implementation method of the first aspect.

In an eleventh aspect, a chip is provided, the chip comprising a processor and a communication interface, the processor reads instructions stored in a memory through the communication interface, and executes the method in the above-mentioned second aspect and any possible implementation manner of the second aspect.

Optionally, as an implementation method, the chip also includes a memory, in which a computer program or instructions are stored, and the processor is used to execute the computer program or instructions stored in the memory. When the computer program or instructions are executed, the processor is used to execute the method in the above-mentioned second aspect and any possible implementation method of the second aspect.

In a twelfth aspect, a communication system is provided, which includes the communication device shown in the fifth and sixth aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a communication system applicable to an embodiment of the present application;

FIG2 is a modular structure diagram of each network element in FIG1;

FIG3 is a schematic diagram of a basic process of a network device acquiring a downlink channel CSI in a traditional FDD system;

FIG4 is a schematic flow chart of a method for designing a multi-band codebook proposed in the present application;

5 is a schematic diagram of a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix generated when the number of antenna ports corresponding to a single polarization direction of the first frequency band and the second frequency band is the same but the number of corresponding subbands is different;

FIG6 is a schematic diagram of adding the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix in the scenario shown in FIG5 according to an element alignment rule;

FIG7 is a schematic diagram of adding the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix in the scenario shown in FIG5 according to another element alignment rule;

8 is a schematic diagram of a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix generated when the number of antenna ports corresponding to a single polarization direction of the first frequency band and the second frequency band are different but the number of corresponding subbands is the same;

FIG9 is a schematic diagram of a matrix generated by adding 0 elements to the second space-frequency joint channel covariance matrix in the scenario shown in FIG8 according to an element alignment rule;

FIG10 is a schematic diagram of a matrix generated by adding 0 elements to the second space-frequency joint channel covariance matrix in the scenario shown in FIG8 according to another element alignment rule;

11 is a schematic diagram of a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix generated when the number of antenna ports corresponding to a single polarization direction of the first frequency band and the second frequency band are different and the corresponding number of subbands are also different;

FIG12 is a schematic diagram of a matrix generated by adding 0 elements to the second space-frequency joint channel covariance matrix in the scenario shown in FIG11 according to an element alignment rule;

13 is a schematic diagram of adding the first space-frequency joint channel covariance matrix in the scenario shown in FIG. 11 and the second space-frequency joint channel covariance matrix in FIG. 12 according to an element alignment rule;

FIG14 is a schematic diagram of a common basis of space-frequency joint features obtained based on the matrix shown in FIG6 ;

FIG15 is a schematic diagram of a common basis of space-frequency joint features obtained based on the matrices of FIG8 and FIG10;

FIG16 is a schematic diagram of a common basis of space-frequency joint features obtained based on the matrix shown in FIG13;

FIG17 is a schematic block diagram of a communication device 200 provided in the present application;

FIG18 is a schematic structural diagram of the communication device 300 provided in the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) communication system, new radio access technology (NR), and future communication systems (such as sixth generation (6G) communication system), etc.

To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail with reference to FIG. 1 .

FIG. 1 is a schematic diagram of a communication system applicable to an embodiment of the present application. As shown in FIG. 1 , the communication system 100 may include at least one network device, such as the network device 110 shown in FIG. 1 ; the communication system 100 may also include at least one terminal device, such as the terminal device 120 shown in FIG. 1 . The network device 110 and the terminal device 120 may communicate via a wireless link. Each communication device, such as the network device 110 or the terminal device 120, may be configured with multiple antennas, which may include at least one transmitting antenna for sending signals and at least one receiving antenna for receiving signals. In addition, each communication device also additionally includes a transmitter chain and a receiver chain, and those skilled in the art may understand that they may include multiple components related to signal transmission and reception (such as processors, modulators, multiplexers, demodulators, demultiplexers or antennas, etc.). Therefore, the network device 110 and the terminal device 120 may communicate via multi-antenna technology.

It should be understood that the network equipment in the wireless communication system can be any equipment with wireless transceiver function. The equipment includes but is not limited to: evolved NodeB (eNB or eNodeB), radio network controller (RNC), NodeB (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home NodeB, HNB), baseband unit (BBU), wireless fidelity (wireless The invention may be an access point (AP), a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP) in a wireless fidelity (WIFI) system, and may also be a gNB in a 5G, such as NR, system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or may also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU).

In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB, such as the CU implementing radio resource control (RRC) and packet data convergence protocol (PDCP). The DU implements the functions of the radio link control (RLC) layer, the media access control (MAC) layer and the physical (PHY) layer. Since the information of the RRC layer will eventually become the information of the PHY layer, or be converted from the information of the PHY layer, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by the DU+CU. It can be understood that the network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the access network (radio access network, RAN), and the CU can also be divided into a network device in the core network (core network, CN), which is not limited in this application.

It should also be understood that the terminal device in the wireless communication system may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiment of the present application may be a mobile phone, a tablet computer (pad), a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), etc. The embodiment of the present application does not limit the application scenario.

FIG2 is a modular structure diagram of each network element in FIG1. As shown in FIG2, in an embodiment of the present application, the network device 110 includes an RRC signaling interaction module, a MAC signaling interaction module, and a PHY signaling and data interaction module. The terminal device 120 also includes an RRC signaling interaction module, a MAC signaling interaction module, and a PHY signaling and data interaction module. The RRC signaling interaction module of the network device 110 is communicatively connected with the RRC signaling interaction module of the terminal device 120 to realize the sending and receiving of RRC signaling. The MAC signaling interaction module of the network device 110 is communicatively connected with the MAC signaling interaction module of the terminal device 120 to realize the sending and receiving of MAC control unit (MAC control element, MAC-CE) signaling.

The PHY signaling and data interaction module of the network device 110 is communicatively connected with the PHY signaling and data interaction module of the terminal device 120, so that the network device 110 can transmit a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) to the terminal device 120. The network device 110 can also receive a physical uplink control channel (PUCCH) and a physical uplink shared channel (PUSCH) sent from the terminal device 120.

To facilitate understanding of the embodiments of the present application, a brief description of the relevant technical contents involved in the present application is first given.

5G communication systems have higher requirements for system capacity and spectrum efficiency. For FDD massive MIMO systems, accurate acquisition of downlink CSI is one of the key factors to ensure efficient operation of the system. Different from TDD systems, FDD systems cannot obtain complete downlink channels through uplink channel estimation because of the large frequency interval between uplink and downlink channels and the incomplete reciprocity between uplink and downlink channels.

FIG3 is a schematic diagram of the basic process of a network device acquiring the CSI of a downlink channel in a traditional FDD system. In a traditional FDD system, the terminal device is required to feedback the CSI of the downlink channel to the network device (e.g., a base station or gNB), and the basic process is shown in FIG3. The network device needs to first send channel measurement configuration information to the terminal device to configure the channel measurement, such as informing the terminal device of the time and behavior of the channel measurement. The network device then sends CSI-RS (also generally referred to as a pilot) to the terminal device for channel measurement. The terminal device measures the channel according to the received CSI-RS, calculates the final CSI feedback amount, and then feeds back the CSI of the downlink channel to the network device. The network device determines the precoding information of the downlink data based on the CSI fed back by the terminal device, thereby precoding and sending the downlink data, that is, the network device can schedule the downlink data according to the fed-back CSI, such as transmitting PDCCH and PDSCH to the terminal device.

CSI is information reported by the receiving end (such as a terminal device) to the transmitting end (such as a network device) in a wireless communication system to describe the channel properties of the communication link. In the 5G communication system, CSI includes but is not limited to channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), CSI-RS resource indicator (CRI), layer indicator (LI) and other parameters. It should be understood that the specific contents of the CSI listed above are only exemplary and should not constitute any limitation to this application. CSI may include one or more of the items listed above, and may also include other information used to characterize CSI in addition to the above-mentioned items, and this application does not limit this.

In order to support high-precision CSI feedback to improve the performance of multi-user multiple-input multiple-output (MU-MIMO) systems, a two-level codebook reporting scheme based on the channel statistical covariance matrix was discussed in the R18 collaborative joint transmission (CJT) codebook standardization process. The scheme is mainly divided into the following steps:

Step 1: The terminal device obtains the channel in the downlink subband dimension based on the measurement of the downlink CSI-RS.

It should be understood that the difference between the maximum frequency and the minimum frequency in a channel is the channel bandwidth, and the channel bandwidth of a channel can be divided into multiple frequency domain resource sets, each of which is a subband. Each subband corresponds to multiple resource blocks (RBs), where an RB is a resource block consisting of all orthogonal frequency division multiplexing (OFDM) symbols in a time slot and 12 subcarriers in the frequency domain.

The terminal device estimates the RB-level downlink channel H _ideal (k) based on the CSI-RS measurement:

Among them, N _Rx represents the number of receiving antennas of the terminal device, N _Tx represents the number of CSI-RS ports, and N _RB represents the number of RBs in the frequency domain.

Then, the above RB-level downlink channel is averaged through the RBs in the sub-band to obtain the sub-band dimension downlink channel

in, is the number of RBs in a subband, and N _SB is the number of subbands in the frequency domain.

Optionally, in this step, any RB-level downlink channel in a sub-band may be selected as a channel of the sub-band dimension of the sub-band.

Step 2: Acquisition of space-frequency joint feature basis. The terminal device performs singular value decomposition (SVD) on the space-frequency joint channel statistical covariance matrix to obtain a singular matrix, and takes the first L columns in the singular matrix as the space-frequency joint feature basis according to the preset or configured L.

For the sub-band dimension downlink channel obtained above, the terminal device first obtains a matrix with N _{Tx /2 rows and N Rx columns for each polarization direction according to the number of CSI-RS ports N Tx} _/ 2 in each polarization direction for a sub-band dimension channel, and then splices the matrices with N _Tx /2 rows and N _Rx columns corresponding to the N _SB _sub -band dimension channels in rows to complete the matrix rearrangement and obtain the channel matrices corresponding to the two polarization directions. and The polarization-averaged space-frequency joint channel covariance matrix is obtained using the above channel matrix:

The terminal device side continuously filters and updates the space-frequency joint channel covariance matrix of the channel based on periodic CSI-RS measurements (α is the filter factor). Assuming that the period of CSI-RS is Δt, the continuously updated space-frequency joint channel statistical covariance matrix is:

Where ||A|| _F represents the Frobenius norm of matrix A, which is defined as the sum of the squares of the absolute values of the elements of matrix A.

Set the space-frequency joint feature base update period T ₀ , and calculate the space-frequency joint channel statistical covariance matrix according to the update period Perform SVD decomposition:

Take the first L eigenvectors to obtain the space-frequency joint feature basis (Common for both polarization directions).

Step 3: Space-frequency joint feature basis projection compression. Since it is expensive for the terminal device to directly feed back the space-frequency joint feature basis to the base station, the space-frequency joint feature basis is projected on a set of discrete Fourier transform (DFT) orthogonal basis vector subspaces. The terminal device only needs to feed back the long-term feedback amount, which includes the space-frequency joint feature basis on the DFT orthogonal basis vectors. The long-term projection coefficient C ₁₃ of the quantum space projection, the selected oversampling group, and the index number of the selected DFT basis vector.

For the obtained projection coefficient C ₁₃ , the terminal may quantize the amplitude in a 4-bit manner and the phase in a 5-bit manner, and the present application does not impose any specific restriction on this.

Step 4: Obtain short-period superposition coefficients. Substitute the channel matrices in the two polarization directions in step 2 into and Projection is performed on the space-frequency joint feature basis after DFT projection quantization reconstruction to obtain the corresponding projection coefficient C ₂ , and the terminal device reports the non-zero coefficients in the projection coefficients and the non-zero coefficient index information to the network device.

Step 5: After the terminal device completes the channel measurement, it needs to report the CSI in the uplink control information (UCI).

For example, the CSI information that the terminal device needs to feed back to the network device includes: the long-period projection coefficient C ₁₃ of the space-frequency joint feature basis projected on the DFT orthogonal basis vector subspace, the index number of the selected oversampling group and the selected DFT basis vector, as well as the non-zero coefficient of the projection coefficient C ₂ and the non-zero coefficient index information.

Step 6: The network device recovers the downlink channel based on the information fed back by the terminal device.

Combined with the above analysis, in the candidate codebook scheme discussed in the R18CJT standard, the codebook structure of a single station can be expressed as in, It is the DFT projection basis vector selected by the space-frequency joint feature basis B. It can be understood that the space-frequency joint feature basis is obtained based on the channel statistical covariance information of the downlink channel, so the terminal device reports it to the network device through a long-term reporting method; and the projection coefficient on the space-frequency joint feature basis is fed back to the network device through a short-term reporting method.

In order to further improve the capacity of the system, multi-frequency fusion technology came into being. The terminal device supports multiple frequency bands at the same time, and the network equipment (such as base station) can send data to the terminal device through multiple frequency bands. Due to the differences in channels of different frequency bands, in the current technology, in order to support multiple frequency bands to send data to the same terminal device, the terminal device needs to design a separate codebook for different frequency bands and report the CSI of each frequency band to the network device separately. As the number of frequency bands supported by terminal devices increases, the reporting overhead of terminal devices is also increasing exponentially. At this time, how to reduce the reporting overhead of terminal devices has become an urgent problem to be solved.

In view of the above problems, considering that in the implementation process of existing products, adjacent frequency bands may use a common antenna panel, at this time the channels of the two frequency bands have a strong correlation in the spatial domain; the interval between the two frequency bands supported by the terminal device is usually close, and the two frequency bands also have a certain correlation in the frequency domain. Therefore, an embodiment of the present application provides a method for multi-band codebook design, which can perform joint codebook design and joint reporting for two or more frequency bands, thereby reducing the overhead of CSI feedback of the terminal device. The method proposed in this application is described in detail below.

Fig. 4 is a schematic flow chart of a method for designing a multi-band codebook proposed in the present application. The method includes the following steps.

S410, the terminal device determines a space-frequency joint characteristic common basis based on a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, and the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, and both the first frequency band and the second frequency band are communication frequency bands between the terminal device and the network device, and the space-frequency joint characteristic common basis is used to determine the space-frequency joint characteristic basis of the first frequency band and the space-frequency joint characteristic basis of the second frequency band.

Optionally, the terminal device determines a space-frequency joint characteristic common basis based on the first channel matrix and the second channel matrix, including: the terminal device determines a first space-frequency joint channel covariance matrix based on the first channel matrix, and determines a second space-frequency joint channel covariance matrix based on the second channel matrix; the terminal device determines the space-frequency joint characteristic common basis based on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix.

In this application, the number of subbands corresponding to the first frequency band is B1, the number of subbands corresponding to the second frequency band is B2, the number of antenna ports corresponding to a single polarization direction of the first frequency band (i.e., the number of CSI-RS ports) is N _t1 /2, and the number of antenna ports corresponding to a single polarization direction of the second frequency band is N _t2 /2 for description, wherein N _t1 /2 is greater than or equal to N _t2 /2, and B1 may be equal to B2 or may not be equal to B2. For the description of determining the space-frequency joint channel covariance matrix corresponding to a frequency band according to the channel matrix corresponding to the frequency band, please refer to the description in the previous step 2, which will be described in detail later, and will not be described here for the time being.

Regarding the method for determining the channel matrix and the space-frequency joint channel covariance matrix corresponding to a frequency band, refer to the description in step 2 of the two-stage codebook reporting scheme based on the channel statistical covariance matrix proposed by R18 in the previous text, which will not be repeated here.

In a possible implementation manner, the terminal device determines the space-frequency joint feature common basis according to the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix, which specifically includes the following steps.

S4101, the terminal device performs an element alignment summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule (also referred to as an element alignment rule), and performs filtering and updating on the summed matrix to obtain a space-frequency joint channel statistical covariance matrix.

It should be understood that the sum of two matrices refers to the addition of corresponding elements in the matrices, and the premise of the addition is that the two matrices must have the same number of rows and columns. Since the rows and columns of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix may be different and cannot be added directly, it is necessary to give an element alignment rule so that the terminal device determines how to add the elements in the two covariance matrices. The following exemplifies the alignment summation of two covariance matrices according to the element alignment rule for different scenarios.

Scenario 1: The number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is equal to the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is greater than the number of subbands B2 corresponding to the first frequency band.

In this scenario, the element alignment rule indicates the information of the B2 subbands in the B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix. Then, the terminal device performs alignment summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the element alignment rule, including: aligning and adding the N _t2 /2 rows corresponding to each subband in the B2 subbands in the second space-frequency joint channel covariance matrix in sequence with the N _t1 /2 rows corresponding to each subband in the B2 subbands indicated by the element alignment rule in the first space-frequency joint channel covariance matrix. The following example is used to illustrate.

For example, as shown in FIG5 , N _t1 /2=N _t2 /2=3, B1=5, B2=3. The first space-frequency joint channel covariance matrix R ₁ is:

Wherein, _Hxy represents the channel of subband x in polarization direction y, x represents the index of the subband, y represents the index of the polarization direction, x=1, 2, 3, 4, 5 are the indices of subband #11, subband #12, subband #13, subband #14, and subband #15 of the first frequency band, respectively, y=1 is the index of one of the two polarization directions, y=2 is the index of the other of the two polarization directions, and _Hxy is a matrix with _Nt1 /2 rows and _NRx columns, where _NRx represents the number of receiving antennas of the terminal device. X is the sum of ^HHH + ^HHH at the corresponding position, where each X is a matrix with ( _Nt1 /2) rows and ( _Nt1 /2) columns. Then, as shown in FIG5, the first space-frequency joint channel covariance matrix is a matrix with (B1* _Nt1 /2) rows and (B1* _Nt1 /2) columns. The number _of rows of the submatrix [ _{X11X12X13X14X15} ] of the first space-frequency joint channel covariance matrix _R1 is the ( _Nt1 / ₂ ) rows corresponding to subband #11, the number _{of rows of the submatrix [X21X22X23X24X25} _] _is _{the (Nt1/2) rows corresponding to subband #12, and the number of rows of the submatrix [X31X32X33X34X35} _] _is _the ₍ _Nt1 _/ ₂ ₎ rows corresponding to _subband # ₁₃ , which will not be repeated. Similarly, the second space-frequency joint channel covariance matrix _R2 is:

Wherein, each Y is a matrix with (N _t2 /2) rows and (N _t2 /2) columns, and the specific derivation process is similar to R ₁ , which will not be repeated here. It should be understood that Y refers to any Y matrix from Y ₁₁ to Y _33. Then, as shown in FIG5, the second space-frequency joint channel covariance matrix R ₂ is a matrix with (B2*N _t2 /2) rows and (B2*N _t2 /2) columns. The number of rows in [Y ₁₁ Y ₁₂ Y ₁₃ ] of the second space-frequency joint channel covariance matrix R ₂ is the (N _t2 /2) rows corresponding to subband #21, the number of rows in the sub-matrix [Y ₂₁ Y ₂₂ Y ₂₃ ] is the (N _t2 /2) rows corresponding to subband #22, and the number of rows in the sub-matrix [Y ₃₁ Y ₃₂ Y ₃₃ ] is the (N _t2 /2) rows corresponding to subband #23, which will not be repeated here.

It should be understood that in the present application, the two space-frequency joint channel covariance matrices are spliced according to the sub-band dimension. Therefore, when the two matrices are added, they also need to be added according to the rows corresponding to the sub-band dimension, that is, a row corresponding to a sub-band in the first space-frequency joint channel covariance matrix is added to a row corresponding to a sub-band in the second space-frequency joint channel covariance matrix.

Afterwards, the (N _t2 /2) rows corresponding to each subband in the B2 subbands in the second space-frequency joint channel covariance matrix are added in sequence with the (N _t1 /2) rows corresponding to each subband in the B2 subbands in the B1 subbands indicated by the element alignment rule in the first space-frequency joint channel covariance matrix, and the summed matrix is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix.

For example, the B2 subband of the B1 subband of the first frequency band indicated by the element alignment rule is subband #11, subband #12, and subband #13, as shown in FIG6 , With R ₁ Perform positional addition, that is, add Y ₁₁ to X ₁₁ , add Y ₁₂ to X ₁₂ , and so on. For another example, the B2 subband of the B1 subband of the first frequency band indicated by the element positional rule is subband #11, subband #13, and subband #15, as shown in FIG7, and Perform counterpoint addition.

Scenario 2: The number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is greater than the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is equal to the number of subbands B2 corresponding to the first frequency band.

In this scenario, the element alignment rule indicates that row _{information and column information of 0 elements are added to each square matrix in the matrix with B2*B2 rows and N t2} _/ 2 columns included in the second space-frequency joint channel covariance matrix. Then, the terminal device performs an alignment summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the element alignment rule, including: determining a fourth space-frequency joint channel covariance matrix, the fourth space-frequency joint channel covariance matrix being a matrix generated by adding N _{t1 /2-N t2} /2 rows and N _t1 /2-N _t2 /2 columns of 0 elements to each of the B2*B2 N _t2 /2*N _t2 /2 square matrices contained in the second covariance matrix according to the row information and column information indicated by the element alignment rule; aligning and adding the N _t1 /2 rows corresponding to the B2 subbands in the fourth space-frequency joint channel covariance matrix in sequence with _the N _t1 /2 rows corresponding to the B2 subbands indicated by the element alignment rule in the first space-frequency joint channel covariance matrix.

For example, as shown in FIG8 , N _t1 /2=4, N _t2 /2=3, B1=B2=3. The first space-frequency joint channel covariance matrix _R1 is:

Wherein, each X is a matrix with rows (N _t1 /2) and columns (N _t1 /2). It should be understood that X refers to any X matrix from X ₁₁ to X _33. Then, as shown in FIG8 , the first space-frequency joint channel covariance matrix R ₁ is a matrix with rows (B1*N _{t1 /2) and columns (N t1} /2). is a matrix of (B1*N _t1 /2). The number of rows in the sub-matrix [X ₁₁ X ₁₂ X ₁₃ ] of the R ₁ matrix is the (N _t1 /2) row corresponding to sub-band #11, the number of rows in the sub-matrix [X ₂₁ X ₂₂ X ₂₃ ] is the (N _t1 /2) row corresponding to sub-band #12, and the number of rows in the sub-matrix [X ₃₁ X ₃₂ X ₃₃ ] is the (N _t1 /2) row corresponding to sub-band #13. Similarly, the second space-frequency joint channel covariance matrix R ₂ is:

Wherein, each Y is a matrix with (N _t2 /2) rows and (N _t2 /2) columns, and the specific derivation process is not repeated here. It should be understood that Y refers to any Y matrix from Y ₁₁ to Y _33. Then, as shown in FIG8 , the second space-frequency joint channel covariance matrix R ₂ is a matrix with (B2*N _t2 /2) rows and (B2*N _t2 /2) columns. The number of rows of the sub-matrix [Y ₁₁ Y ₁₂ Y ₁₃ ] of the R ₂ matrix is the (N _t2 /2) rows corresponding to sub-band #21, the number of rows in the sub-matrix [Y ₂₁ Y ₂₂ Y ₂₃ ] is the (N _t2 /2) rows corresponding to sub-band #22, and the number of rows of the sub-matrix [Y ₃₁ Y ₃₂ Y ₃₃ ] is the (N _t2 /2) rows corresponding to sub-band #23, which is not repeated here.

As can be seen from the above, the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix need to be added according to the rows corresponding to the subband dimension, that is, [Y ₁₁ Y ₁₂ Y ₁₃ ] is added to [Y ₁₁ Y ₁₂ Y ₁₃ ], [Y ₂₁ Y ₂₂ Y ₂₃ ] is added to [Y ₂₁ Y ₂₂ Y ₂₃ ], and [Y ₃₁ Y ₃₂ Y ₃₃ ] is added to [X ₃₁ X ₃₂ X ₃₃ ]. However, since each X is a matrix with (N _t1 /2) rows and (N _t1 /2) columns, and each Y is a matrix with (N _t2 /2) rows and (N _t2 /2) columns, they cannot be added directly.

Therefore, before adding, N _t1 /2-N _t2 /2 rows of 0 elements and N _t1 /2-N t2 /2 columns of 0 elements must be added in each Y according to the row information and column information of adding 0 elements indicated by the element alignment rule, so as to make it a matrix with (N _t1 /2) rows and (N _t1 /2) columns. For example, the element alignment rule indicates that N _t1 /2-N _t2 /2 rows of 0 elements are added after the second row of each Y, and N _t1 _/ 2-N _t2 /2 columns of 0 elements are added after the first column, and the second space-frequency joint channel covariance matrix R ₂ after adding 0 elements is shown in FIG9. Alternatively, the element alignment rule indicates that N _t1 /2-N _t2 /2 rows of 0 elements are added after the last row of each Y, and N _t1 /2-N _t2 /2 columns of 0 elements are added after the last column, and the second space-frequency joint channel covariance matrix R ₂ after adding 0 elements is shown in FIG10. The present application does not limit the row information and column information of adding 0 elements in the Y matrix. Afterwards, each X and Y is a matrix with rows (N _t1 /2) and columns (N _t1 /2), that is, R ₁ and R ₂ have the same rows and columns, and can be directly added, that is, Y ₁₁ is added to X ₁₁ , Y ₁₂ is added to X ₁₂ , and so on, and the summed matrix is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix.

Scenario 3: The number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is greater than the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is greater than the number of subbands B2 corresponding to the first frequency band.

In this scenario, the element alignment rule indicates the information of the B2 subbands in the B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, as well as the row information and column information of adding 0 elements to each square matrix in the B2*B2 square matrix with N _t2 /2 rows and N _t2 /2 columns contained in the second covariance matrix. Then, the terminal device performs an alignment summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the element alignment rule, including: determining a fourth space-frequency joint channel covariance matrix, the fourth space-frequency joint channel covariance matrix being a matrix generated by adding N _{t1 /2-N t2} /2 rows and N _t1 /2-N _t2 /2 columns of 0 elements to each square matrix of the square matrix with _B2 *B2 rows and N _t2 /2 columns in the second covariance matrix according to the row information and column information indicated by the element alignment rule; aligning and adding the N _t1 /2 rows corresponding to the B2 subbands in the fourth space-frequency joint channel covariance matrix in sequence with the N _t1 /2 rows corresponding to the B2 subbands indicated by the element alignment rule in the first space _- frequency joint channel covariance matrix.

For example, as shown in FIG11 , N _t1 /2=4, N _t2 /2=3, B1=3, B2=2. The first space-frequency joint channel covariance matrix _R1 is:

Wherein, each X is a matrix with (N _t1 /2) rows and (N _t1 /2) columns, and the specific derivation process is not repeated here. It should be understood that X refers to any X matrix from X ₁₁ to X _33. Then, as shown in FIG11, the first space-frequency joint channel covariance matrix is a matrix with (B1*N _t1 /2) rows and (B1*N _t1 /2) columns. The number of rows of the sub-matrix [X ₁₁ X ₁₂ X ₁₃ X ₁₄ X ₁₅ ] of the matrix R ₁ is the (N t1 /2) rows corresponding to sub-band #11, the number of rows of the sub-matrix [X ₂₁ X ₂₂ X ₂₃ X ₂₄ X ₂₅ ] is the (N _t1 /2) rows corresponding to sub-band #12, and the number of rows of the sub-matrix [X ₃₁ X ₃₂ X ₃₃ X ₃₄ X ₃₅ ] is the ( _{N t1} _/ 2) rows corresponding to sub-band #13.

Similarly, the second space-frequency joint channel covariance matrix _R2 is:

Wherein, each Y is a matrix with (N _t2 /2) rows and (N _t2 /2) columns, and the specific derivation process is not repeated here. It should be understood that Y refers to any Y matrix from Y ₁₁ to Y _22. Then, as shown in FIG11, the second space-frequency joint channel covariance matrix R ₂ is a matrix with (B2*N _t2 /2) rows and (B2*N _t2 /2) columns, and the number of rows of the sub-matrix [Y ₁₁ Y ₁₂ ] of the matrix R ₂ is the (N _t2 /2) rows corresponding to sub-band #21, and the number of rows of the sub-matrix [Y ₂₁ Y ₂₂ ] is the (N _t2 /2) rows corresponding to sub-band #22.

It can be understood that the matrix addition in scenario 3 can be achieved by combining the processing methods of matrix addition in scenario 1 and scenario 2.

First, the same as the processing method in scenario 2, the row information and column information of adding 0 elements must be followed as indicated by the element alignment rule before adding, and N _t1 /2-N _t2 /2 rows and N _t1 /2-N _t2 /2 columns of 0 elements must be added to each Y, so that it becomes a matrix with (N _t1 /2) rows and (N _t1 /2) columns. Afterwards, the same as the processing method in scenario 1, the (N _t1 /2) rows corresponding to each subband in the _B2 subbands in the matrix after adding 0 elements to R 2 are added to the (N _t1 /2) rows corresponding to each subband in the B1 subbands and the B2 subbands indicated by the element alignment rule in the first space-frequency joint channel covariance matrix, and the summed matrix is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix. An example is given for illustration.

For example, the element alignment rule indicates that N _t1 /2-N _t2 /2 rows of 0 elements are added after the last row of each Y, and N _t1 /2-N _t2 /2 columns of 0 elements are added after the last column, and it also indicates that the B2 subbands in the B1 subbands of the first frequency band are subbands #11 and subband #13. Then, the matrix after R ₂ is increased by 0 elements according to the element alignment rule is shown in Figure 12. Afterwards, the matrix shown in Figure 12 and the (N _t1 /2) rows corresponding to each subband in the B2 subbands in the B1 subbands in the first space-frequency joint channel covariance matrix are added in sequence, and the schematic diagram of the addition is shown in Figure 13.

Scenario 4: The number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is equal to the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is equal to the number of subbands B2 corresponding to the first frequency band.

Since the number of antenna ports and subbands of the first frequency band and the second frequency band are the same, the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix are matrices with the same rows and columns, so the two covariance matrices can be directly added. Similarly, the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix need to be added according to the rows corresponding to the subband dimension.

Optionally, the N _t2 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are aligned and added in sequence with the N _t1 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix, and the summed matrix is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix.

Optionally, the N _t2 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are aligned and added in sequence with the N _t1 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix, and the summed matrix is divided by 2 and then filtered and updated to obtain the space-frequency joint channel statistical covariance matrix.

It should be understood that the space-frequency joint channel statistical covariance matrix obtained by the terminal device in the present application is a behavior (B1*N _t1 /2), A matrix with columns (B1*N _t1 /2).

S4102, the terminal device performs singular value decomposition on the space-frequency joint channel statistical covariance matrix to obtain a singular matrix, and selects the first L columns of the singular matrix as the space-frequency joint feature common basis.

Optionally, L may be a preset value or a network device configuration, which is not limited in this application. It should be understood that the first L columns of the singular matrix correspond to the columns of the singular matrix corresponding to the first L values with larger singular values.

It should be understood that the value range of L in scenarios 1 and 4 is 1≤L≤B2*N _t2 /2, and the value range of L in scenarios 2 and 3 is 1≤L≤B2*N _t1 /2. In other words, the value of L cannot exceed the number of matrix columns actually added in the two covariance matrices.

It should also be understood that the space-frequency joint feature common basis in the embodiment of the present application is a matrix with a row (B1*N _t1 /2) and a column of L. For example, the matrix after addition in FIG6 is filtered and updated to obtain a space-frequency joint channel statistical covariance matrix, as shown in FIG14, and the first L=6 columns of the space-frequency joint channel statistical covariance matrix are intercepted as the space-frequency joint feature common basis.

S420, the terminal device sends information indicating the common basis of the space-frequency joint feature to the network device. Correspondingly, the network device receives the information indicating the common basis of the space-frequency joint feature from the terminal device.

It should be understood that the network device recovers the space-frequency joint feature common basis according to the information of the space-frequency joint feature common basis. The recovery process is the same as the way of recovering the downlink channel in the two-level codebook reporting scheme based on the channel statistical covariance matrix proposed in the current R18 standard, and will not be described here.

Optionally, the information used to indicate the common basis of the space-frequency joint feature includes: the index number of the discrete Fourier transform basis vector corresponding to the selected oversampling group, and the projection coefficient of the common basis of the space-frequency joint feature on the discrete Fourier transform basis vector. It should be understood that the terminal device can refer to the description in the prior art for feeding back the above information to the network device through a long-period reporting method or a short-period reporting method, which will not be repeated here.

S430, the network device determines a space-frequency joint feature basis of a first frequency band and a space-frequency joint feature basis of a second frequency band according to information of the space-frequency joint feature common basis.

The network device first recovers the space-frequency joint characteristic common basis based on the information used to indicate the space-frequency joint characteristic common basis, and then the network device determines the space-frequency joint characteristic common basis as the space-frequency joint characteristic common basis of the first frequency band; the network device processes the space-frequency joint characteristic common basis according to the element alignment rule (i.e., element selection) to determine the space-frequency joint characteristic common basis of the second frequency band.

The following describes, for different scenarios, how to select elements from the space-frequency joint feature common basis to determine the space-frequency joint feature basis of the second frequency band.

In this scenario, the element alignment rule indicates information of B2 subbands in the B1 subbands of the first frequency band for calculating the space-frequency joint channel statistical covariance matrix. Then, the network device selects elements of the space-frequency joint feature common basis according to the element alignment rule to determine the space-frequency joint feature basis of the second frequency band, including: determining B2*N _t2 /2 rows of the space-frequency joint feature common basis as the space-frequency joint feature basis of the second frequency band, wherein B2*N _t2 /2 rows are the rows corresponding to the N _t1 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands indicated by the element alignment rule. In other words, in this scenario, the bandwidths corresponding to the two frequency bands are different, and the characteristic basis of the frequency band with fewer subbands (i.e., the second frequency band) can be obtained by truncating the characteristic basis (i.e., the common basis) of the frequency band with more subbands (i.e., the first frequency band).

For example, the network device receives the space-frequency joint characteristic common basis shown in Figure 14. It can be seen from the above that the B2 subbands indicated by the element alignment rule corresponding to the space-frequency joint characteristic common basis are subband #11, subband #13, and subband #15 in the first frequency band. Therefore, as shown in Figure 14, the network device determines that the elements of the rows corresponding to the N _t1 /2 rows corresponding to subband #11, subband #13, and subband #15, respectively, in the space-frequency joint channel statistical covariance matrix are the space-frequency joint characteristic basis of the second frequency band.

In this scenario, the element alignment rule indicates that the second covariance matrix contains B2*B2 rows of N _t2 /2 and columns of N _t2 /2 squares. Then, the network device selects elements from the space-frequency joint feature common basis according to the element alignment rule to determine the space-frequency joint feature basis of the second frequency band, including: extracting elements from B2*N _t2 /2 rows in the space-frequency joint feature common basis, where B2*N t2 /2 rows are the rows corresponding to the N _t2 _/ 2 rows of the B2 subbands in the third space-frequency joint channel covariance matrix in the space-frequency joint channel statistical covariance matrix, wherein the third space-frequency joint channel covariance matrix is a square matrix containing B2*B2 rows of N _t2 /2 and N _t2 /2 columns in the second covariance matrix, after adding N _t1 /2-N _t2 /2 rows and N _t1 /2-N _t2 /2 columns of 0 elements according to the row information and column information indicated by the element alignment rule, and the N t2 /2 rows corresponding to each of the B2 subbands do not include the N _t1 / ₂ /2 rows corresponding to the B2 subbands. /2 rows where the added 0 elements are located; the extracted elements are concatenated to obtain the space-frequency joint feature basis of the second frequency band.

For example, in the second covariance matrix shown in FIG8 , the square matrix with B2*B2 rows of N _t2 /2 and columns of N _t2 /2 is the 9 sub-matrices Y ₁₁ to Y _33. It should be understood that in this scenario, when the number of antenna ports in each frequency band is different, the space-frequency joint feature basis can contain the information of each sub-band. It is not advisable to directly truncate the space-frequency joint feature basis (i.e., the common basis) of the first frequency band to obtain the space-frequency joint feature basis of the second frequency band, which may lose the information of some sub-bands of the second frequency band. Therefore, in order to better design the space-frequency joint feature basis of the second frequency band, it is necessary to extract the space-frequency joint feature basis of the first frequency band according to the number of antenna ports corresponding to the single polarization direction of the second frequency band, so as to ensure that the extracted space-frequency joint feature basis of the second frequency band contains the information of each sub-band.

For example, the network device receives the space-frequency joint feature common basis shown in FIG15, which is the matrix in FIG10 (i.e., the matrix obtained by adding N _t1 /2-N _t2 /2 rows of 0 elements after the last row of each Y matrix of the second space-frequency joint channel covariance matrix shown in FIG8, and adding N _t1 /2-N _t2 /2 columns of 0 elements after the last column) and the first space-frequency joint channel covariance matrix in FIG8, and then filtering and updating, and the space-frequency joint channel statistical covariance matrix is obtained by truncating the first L = 6 columns. Therefore, the network device splices the rows except the rows corresponding to the 0 elements in FIG15 to obtain the space-frequency joint feature basis of the second frequency band.

In this scenario, the element alignment rule indicates the information of the B2 subbands in the B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, as well as the row information and column information of adding 0 elements to each square matrix in the B2*B2 square matrix with N _t2 /2 rows and N _t2 /2 columns contained in the second covariance matrix. Then, the network device selects elements from the space-frequency joint feature common basis according to the element alignment rule to determine the space-frequency joint feature basis of the second frequency band, including: determining B2*N _t1 /2 rows of the space-frequency joint feature common basis as the first space-frequency joint feature basis, wherein B2*N _t2 /2 rows are rows corresponding to the B2 subbands in the fourth space-frequency joint channel covariance matrix in the space-frequency joint channel statistical covariance matrix, and the fourth space-frequency joint channel covariance matrix is a matrix generated by adding N _t1 /2-N _t2 /2 rows and N _t1 /2-N _{t2 /2 columns of 0 elements to each square matrix of the square matrix with B2*B2 rows of N t2} /2 and N _t2 /2 columns in the second space-frequency joint channel covariance matrix according to the row _information and column information indicated by the element alignment rule; extracting the elements in B2*N _t2 /2 rows in the first space-frequency joint feature basis _, B2*N _t2 /2 rows are the rows in the space-frequency joint channel statistical covariance matrix corresponding to the N _t2 /2 rows corresponding to each of the B2 subbands in the fourth space-frequency joint channel covariance matrix, and the N _t2 /2 rows corresponding to each of the B2 subbands do not include the rows where the 0 elements added in the N _t1 /2 rows corresponding to the B2 subbands are located; the extracted elements are spliced to obtain the space-frequency joint feature basis of the second frequency band.

For example, the matrix after addition in FIG13 is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix, and the first L=6 columns are intercepted as the space-frequency joint feature common basis, and the network device receives the space-frequency joint feature common basis shown in FIG16. As can be seen from the above, the B2 subbands indicated by the element alignment rule corresponding to the space-frequency joint feature common basis are subband #11 and subband #13 in the first frequency band, respectively. Therefore, the network device determines that the elements of the N _t1 /2 rows corresponding to subband #11 and subband #13 in the space-frequency joint channel statistical covariance matrix are the space-frequency joint feature basis of the second frequency band, wherein the N _t2 /2 rows corresponding to each subband in the B2 subbands do not include the rows where the 0 elements added in the N _t1 /2 rows corresponding to the B2 subbands are located.

It should be understood that since the number of antenna ports and subbands in the first frequency band and the second frequency band are the same, the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix are matrices with the same rows and columns. Therefore, the network device determines the space-frequency joint characteristic common basis as the space-frequency joint characteristic basis of the second frequency band.

It should be understood that when the number of antenna ports N _t1 /2 corresponding to a single polarization direction of the first frequency band is greater than the number of antenna ports N _t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of subbands B1 corresponding to the first frequency band is less than the number of subbands B2 corresponding to the second frequency band, the process of adding the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix to obtain the space-frequency joint channel statistical covariance matrix is basically similar to the description in scenario 3 in S410. Specifically, before the two space-frequency joint channel covariance matrices are added, it is necessary to first add 0 elements to each of the matrices with B2*B2 rows (N _t2 /2) and columns (N _t2 /2) in the second space-frequency joint channel covariance matrix to make it a matrix with one row (N _t1 /2) and one column (N _t1 /2). Then, the N _t1 corresponding to the B1 subbands of the first space-frequency joint channel covariance matrix is added. /2 rows and the N _t1 /2 rows corresponding to the B1 subbands in the B2 subbands of the second space-frequency joint channel covariance matrix after adding 0 elements are added in sequence, and the summed matrix is filtered and updated to obtain the space-frequency joint channel statistical covariance matrix. Among them, the information of the B1 subbands used to calculate the space-frequency joint channel statistical covariance matrix in the B2 subbands of the second frequency band, and the row information and column information of adding 0 elements in each matrix in the square matrix of N _t2 /2 and N _t2 /2 contained in the second covariance matrix are indicated by the element alignment rule. Afterwards, the terminal device performs singular value decomposition on the space-frequency joint channel statistical covariance matrix to obtain a singular matrix, selects the first L columns of the singular matrix as the space-frequency joint feature common basis, and sends it to the network device. The process of the network device in this scenario obtaining the space-frequency joint feature basis of the second frequency band through the space-frequency joint feature common basis is basically similar to the description in scenario 3 in S430. Specifically, the network device first intercepts the row corresponding to the B1 subband of the first frequency band in the space-frequency joint feature common basis, and then splices the intercepted rows except the row corresponding to the 0 element to obtain the space-frequency joint feature basis of the second frequency band.

It should also be understood that the element alignment rules may be pre-set or configured by the network device for the terminal device, and this application does not make any specific limitation on this.

It should also be understood that the element alignment rule in the present application may also be referred to as a covariance matrix addition rule or other names, and the present application does not limit this.

It should also be understood that the space-frequency joint feature common base in the present application may also be called other names, and the present application does not limit this.

The above technical solution provides a specific method for the terminal device to design a joint feature base for two frequency bands in different scenarios. In this way, the terminal device only needs to feedback a space-frequency joint feature common base to the network device for the two frequency bands, thereby reducing the overhead of the terminal device to feedback CSI.

It should also be understood that the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and/or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

It should also be understood that in some of the above embodiments, the devices in the existing network architecture are mainly used as examples for exemplary description, and it should be understood that the embodiments of the present application do not limit the specific form of the devices. For example, devices that can achieve the same function in the future are applicable to the embodiments of the present application.

It can be understood that in the above-mentioned various method embodiments, the methods and operations implemented by devices (such as the above-mentioned terminal devices, network devices, etc.) can also be implemented by components of the devices (such as chips or circuits).

The method provided by the embodiment of the present application is described in detail above in conjunction with Figures 1 to 16. The above method is mainly introduced from the perspective of interaction between the terminal device and the network device. It can be understood that the terminal device and the network device, in order to implement the above functions, include hardware structures and/or software modules corresponding to the execution of each function.

Those skilled in the art should be aware that the units and algorithm steps of each example described in combination with the embodiments disclosed herein are The present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is performed 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 application.

Hereinafter, the communication device provided by the embodiment of the present application is described in detail in conjunction with Figures 17 and 18. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, the content not described in detail can refer to the method embodiment above. For the sake of brevity, some contents are not repeated. The embodiment of the present application can divide the functional modules of the terminal device or network device according to the above method example. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic, which is only a logical function division, and there may be other division methods in actual implementation. The following is an example of dividing each functional module corresponding to each function.

The above describes in detail the method for data transmission provided by the present application. The following describes the communication device provided by the present application. In one possible implementation, the device is used to implement the steps or processes corresponding to the network device in the above method embodiment. In another possible implementation, the device is used to implement the steps or processes corresponding to the terminal device in the above method embodiment.

FIG17 is a schematic block diagram of a communication device 200 provided in an embodiment of the present application. As shown in FIG17 , the device 200 may include a communication unit 210 and a processing unit 220. The communication unit 210 may communicate with the outside, and the processing unit 220 is used for data processing. The communication unit 210 may also be referred to as a communication interface or a transceiver unit.

In one possible design, the device 200 can implement steps or processes corresponding to those executed by the terminal device in the above method embodiment, wherein the processing unit 220 is used to execute processing-related operations of the terminal device in the above method embodiment, and the communication unit 210 is used to execute sending-related operations of the terminal device in the above method embodiment.

In another possible design, the device 200 may implement steps or processes corresponding to those executed by the network device in the above method embodiment, wherein the communication unit 210 is used to execute reception-related operations of the network device in the above method embodiment, and the processing unit 220 is used to execute processing-related operations of the network device in the above method embodiment.

It should be understood that the device 200 here is embodied in the form of a functional unit. The term "unit" here may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a merged logic circuit and/or other suitable components that support the described functions. In an optional example, those skilled in the art can understand that the device 200 can be specifically the terminal device in the above embodiment, and can be used to execute the various processes and/or steps corresponding to the terminal device in the above method embodiment, or the device 200 can be specifically the network device in the above embodiment, and can be used to execute the various processes and/or steps corresponding to the network device in the above method embodiment. To avoid repetition, it will not be repeated here.

The apparatus 200 of each of the above-mentioned schemes has the function of implementing the corresponding steps executed by the terminal device in the above-mentioned method, or the apparatus 200 of each of the above-mentioned schemes has the function of implementing the corresponding steps executed by the network device in the above-mentioned method. The functions can be implemented by hardware, or can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions; for example, the communication unit can be replaced by a transceiver (for example, the sending unit in the communication unit can be replaced by a transmitter, and the receiving unit in the communication unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor, respectively performing the sending and receiving operations and related processing operations in each method embodiment.

In addition, the communication unit may also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit. In an embodiment of the present application, the device in FIG. 17 may be an AP or STA in the aforementioned embodiment, or may be a chip or a chip system, for example, a system on chip (SoC). The communication unit may be an input and output circuit or a communication interface; the processing unit may be a processor or a microprocessor or an integrated circuit integrated on the chip. This is not limited here.

18 is a schematic block diagram of a communication device 300 provided in an embodiment of the present application. The device 300 includes a processor 310 and a transceiver 320. The processor 310 and the transceiver 320 communicate with each other through an internal connection path, and the processor 310 is used to execute instructions to control the transceiver 320 to send signals and/or receive signals.

Optionally, the device 300 may further include a memory 330, and the memory 330 communicates with the processor 310 and the transceiver 320 through an internal connection path. The memory 330 is used to store instructions, and the processor 310 can execute the instructions stored in the memory 330. In one possible implementation, the device 300 is used to implement the various processes and steps corresponding to the terminal device in the above method embodiment. In another possible implementation, the device 300 is used to implement the various processes and steps corresponding to the network device in the above method embodiment.

It should be understood that the device 300 may specifically be a terminal device or a network device in the above embodiments, or may be a chip or a chip system. Correspondingly, the transceiver 320 can be the transceiver circuit of the chip, which is not limited here. Specifically, the device 300 can be used to execute the various steps and/or processes corresponding to the terminal device or network device in the above-mentioned method embodiment. Optionally, the memory 330 may include a read-only memory and a random access memory, and provide instructions and data to the processor. A part of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type. The processor 310 can be used to execute instructions stored in the memory, and when the processor 310 executes instructions stored in the memory, the processor 310 is used to execute the various steps and/or processes of the above-mentioned method embodiment corresponding to the terminal device or network device.

In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software modules in a processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The processor in the embodiment of the present application can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiment of the present application. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined and performed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

In addition, the present application also provides a computer-readable storage medium, in which computer instructions are stored. When the computer instructions are executed on a computer, the operations and/or processes performed by a terminal device or a network device in each method embodiment of the present application are executed.

The present application also provides a computer program product, which includes computer program code or instructions. When the computer program code or instructions are run on a computer, the operations and/or processes performed by a terminal device or a network device in each method embodiment of the present application are executed.

In addition, the present application also provides a chip, the chip including a processor. A memory for storing a computer program is provided independently of the chip, and the processor is used to execute the computer program stored in the memory, so that the operation and/or processing performed by the terminal device or the network device in any method embodiment is executed.

Furthermore, the chip may further include a communication interface. The communication interface may be an input/output interface, or an interface circuit, etc. Furthermore, the chip may further include a memory.

In addition, the present application also provides a communication system, including the terminal device and network device in the embodiments of the present application.

It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

It can be appreciated by a person skilled in the art that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or in combination with computer software and electronic hardware. Whether these functions are performed in hardware or software 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 this application. It can be clearly understood by a person skilled in the art that for the convenience and simplicity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the unit is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

If the functions are implemented in the form of software functional units 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 present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard drives, ROM, RAM, magnetic disks, or optical disks.

It should be understood that the "embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments in the entire specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

It should also be understood that the ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority or importance of multiple objects. For example, the first information and the second information do not represent the difference in information volume, content, priority or importance.

It should also be understood that in the present application, "when", "if" and "if" all mean that the network element will take corresponding actions under certain objective circumstances, and do not limit the time, nor do they require the network element to take judgment actions when implementing it, nor do they mean that there are other limitations.

It should also be understood that in this application, "at least one" means one or more, and "plurality" means two or more. "At least one item" or similar expressions means one or more items, that is, any combination of these items, including any combination of single items or plural items. For example, at least one item of a, b, or c means: a, b, c, a and b, a and c, b and c, or a, b and c.

It should also be understood that the meaning of expressions similar to "the project includes one or more of the following: A, B, and C" in this application, unless otherwise specified, generally means that the project can be any of the following: A; B; C; A and B; A and C; B and C; A, B and C; A and A; A, A and A; A, A and B; A, A and C, A, B and B; A, C and C; B and B, B, B and B, B, B and C, C and C; C, C and C, and other combinations of A, B and C. The above is an example of three elements, A, B and C, to illustrate the optional items of the project. When it is expressed as "the project includes at least one of the following: A, B, ..., and X", that is, when there are more elements in the expression, the items that can be applied to the project can also be obtained according to the above rules.

It should also be understood that the term "and/or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character "/" generally indicates that the associated objects before and after are in an "or" relationship. For example, A/B means: A or B.

It should also be understood that in each embodiment of the present application, "A corresponds to B" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and/or other information.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

A method for designing a multi-band codebook, characterized by comprising:

The terminal device determines a space-frequency joint characteristic common basis according to a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, the first frequency band and the second frequency band are both communication frequency bands between the terminal device and a network device, and the space-frequency joint characteristic common basis is used to determine a space-frequency joint characteristic basis of the first frequency band and a space-frequency joint characteristic basis of the second frequency band;

The terminal device sends information indicating the common basis of the space-frequency joint feature to the network device.
The method according to claim 1, characterized in that the terminal device determines the space-frequency joint characteristic common basis according to the first channel matrix and the second channel matrix, comprising:

The terminal device determines a first space-frequency joint channel covariance matrix according to the first channel matrix, and determines a second space-frequency joint channel covariance matrix according to the second channel matrix;

The terminal device determines the space-frequency joint feature common basis according to the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix.
The method according to claim 2 is characterized in that the number of antenna ports N t1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports N t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of sub-bands B1 corresponding to the first frequency band is greater than or equal to the number of sub-bands B2 corresponding to the second frequency band;

The terminal device determines the space-frequency joint feature common basis according to the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix, including:

The terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, and determines a space-frequency joint channel statistical covariance matrix according to the summed matrices;

The terminal device determines a singular matrix according to the space-frequency joint channel statistical covariance matrix, and selects the first L columns of the singular matrix as the space-frequency joint characteristic common basis, wherein L is less than or equal to the smaller value of B1*N t1 /2 and B2*N t2 /2.
The method according to claim 3, characterized in that N t1 /2 is equal to N t2 /2, B1 is greater than B2, and the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix,

The terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, including:

The N t2 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are aligned and added in sequence with the N t1 /2 rows corresponding to each of the B2 subbands of the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix.
The method according to claim 3, characterized in that N t1 /2 is greater than N t2 /2, and B1 is equal to B2, and the first rule indicates that row information and column information of 0 elements are added to each of the B2*B2 square matrices of N t2 /2*N t2 /2 contained in the second covariance matrix,

The terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, including:

Determine a third space-frequency joint channel covariance matrix, where the third space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of B2*B2 rows and N t2 /2 columns contained in the second covariance matrix according to the row information and column information indicated by the first rule;

The N t1 /2 rows corresponding to each of the B2 subbands in the third space-frequency joint channel covariance matrix are aligned and added in sequence with the N t1 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix.
The method according to claim 3, characterized in that N t1 /2 is greater than N t2 /2, and B1 is greater than B2,

The first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and row information and column information of adding 0 elements to each of the B2*B2 N t2 /2*N t2 /2 square matrices contained in the second covariance matrix,

The terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, including:

Determine a fourth space-frequency joint channel covariance matrix, where the fourth space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of B2*B2 rows with N t2 /2 rows and N t2 /2 columns in the second covariance matrix according to the row information and column information indicated by the first rule;

The N t1 /2 rows corresponding to each of the B2 subbands in the fourth space-frequency joint channel covariance matrix are aligned and added in sequence with the N t1 /2 rows corresponding to each of the B2 subbands of the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix.
The method according to claim 3, characterized in that N t1 /2 is equal to N t2 /2, and B1 is equal to B2,

The terminal device performs positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, including:

The N t1 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are sequentially aligned and added with the N t2 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix.
The method according to any one of claims 3 to 7, characterized in that the method further comprises:

The terminal device receives first indication information sent from the network device, the first indication information includes the first rule, and the first indication information is used to instruct the terminal device to perform a positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.
The method according to any one of claims 3 to 7, characterized in that the method further comprises:

The terminal device sends second indication information to the network device, the second indication information includes the first rule, and the second indication information instructs the network device to process the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.
The method according to any one of claims 1-9 is characterized in that the information used to indicate the common basis of the space-frequency joint characteristics includes: the selected oversampling group, the index number of the discrete Fourier transform DFT basis vector corresponding to the oversampling group, and the projection coefficients of the common basis of the space-frequency joint characteristics on the DFT basis vector.
A method for designing a multi-band codebook, characterized by comprising:

The network device receives information indicating a space-frequency joint feature common basis from the terminal device, where the space-frequency joint feature common basis is determined by the terminal device according to a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, and both the first frequency band and the second frequency band are communication frequency bands between the network device and the terminal device;

The network device determines a space-frequency joint feature basis of the first frequency band and a space-frequency joint feature basis of the second frequency band according to information of the space-frequency joint feature common basis.
The method according to claim 11 is characterized in that the space-frequency joint characteristic common basis is determined based on a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix, the first space-frequency joint channel covariance matrix is determined based on the first channel matrix, and the second space-frequency joint channel covariance matrix is determined based on the second space-frequency joint channel covariance matrix.
The method according to claim 12, characterized in that the number of antenna ports N t1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports N t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of sub-bands B1 corresponding to the first frequency band is greater than or equal to the number of sub-bands B2 corresponding to the second frequency band,

The space-frequency joint characteristic common basis is composed of the first L columns of a singular matrix, the singular matrix is determined according to a space-frequency joint channel statistical covariance matrix, and the space-frequency joint channel statistical covariance matrix is obtained by performing a positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, wherein L is less than or equal to a smaller value of B1*N t1 /2 and B2*N t2 /2;

The network device determines, according to the space-frequency joint feature common basis, a space-frequency joint feature basis of the first frequency band and a space-frequency joint feature basis of the second frequency band, including:

The network device determines the space-frequency joint feature common basis as the space-frequency joint feature basis of the first frequency band;

The network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band.
The method according to claim 13, characterized in that N t1 /2 is equal to N t2 /2, B1 is greater than B2, and the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix,

The network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including:

Determine B2*N t2 /2 rows of the space-frequency joint characteristic common basis as the space-frequency joint characteristic basis of the second frequency band, wherein the B2*N t2 /2 rows are the N t1 /2 rows corresponding to each subband in the B2 subbands of the first frequency band indicated by the first rule in the space-frequency joint channel statistical covariance matrix.
The method according to claim 13, characterized in that N t1 /2 is greater than N t2 /2, and B1 is equal to B2, the first rule indicates that the second covariance matrix contains B2*B2 rows of N t2 /2 and columns of N t2 /2, and each square matrix contains row information and column information of 0 elements,

The network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including:

Extracting elements in B2*N t2 /2 rows in the space-frequency joint characteristic common basis, wherein the B2*N t2 /2 rows are the N t2 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band, wherein the third space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of zero elements to the square matrix containing B2 *B2 rows of N t2 /2 and N t2 /2 columns in the second covariance matrix according to the row information and column information indicated by the first rule, and the N t2 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band do not include the rows where the zero elements added to the N t1 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band are located;

The extracted elements are concatenated to obtain a space-frequency joint feature basis of the second frequency band.
The method according to claim 13, characterized in that N t1 /2 is greater than N t2 /2, and B1 is greater than B2, the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and the B2*B2 rows contained in the second covariance matrix are N t2 /2, and the columns are row information and column information of each square matrix in the N t2 /2 square matrix with 0 elements added,

The network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including:

Determine the B2*N t1 /2 rows of the space-frequency joint feature common basis as the third space-frequency joint feature basis, wherein the B2*N t1 /2 rows are the rows corresponding to the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix, and the N t1 /2 rows corresponding to the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix correspond to the rows in the space-frequency joint channel statistical covariance matrix, and the fourth space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of the square matrix with B2*B2 rows of N t2 /2 and N t2 /2 columns in the second space-frequency joint channel covariance matrix according to the row information and column information indicated by the first rule;

Extracting elements in the B2*N t2 /2 rows in the third space-frequency joint characteristic common basis, the B2*N t2 /2 rows are the N t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix in the space-frequency joint channel statistical covariance matrix, and the N t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix do not include the rows where the 0 elements added in the N t1 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix are located;

The extracted elements are concatenated to obtain a space-frequency joint feature basis of the second frequency band.
The method according to claim 13, characterized in that N t1 /2 is equal to N t2 /2, and B1 is greater than B2,

The network device selects elements from the space-frequency joint feature common basis according to the first rule to determine the space-frequency joint feature basis of the second frequency band, including:

The network device determines the space-frequency joint feature common basis as the space-frequency joint feature basis of the second frequency band.
The method according to any one of claims 13 to 17, characterized in that the method further comprises:

The network device sends first indication information to the terminal device, the first indication information includes the first rule, and the first indication information is used to instruct the terminal device to perform positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.
The method according to any one of claims 13 to 17, characterized in that the method further comprises:

The network device receives second indication information sent from the terminal device, where the second indication information includes the first rule, and the second indication information instructs the network device to intercept the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.
The method according to any one of claims 11-19 is characterized in that the information used to indicate the common basis of the space-frequency joint characteristics includes: the selected oversampling group, the index number of the discrete Fourier transform DFT basis vector corresponding to the oversampling group, and the projection coefficients of the common basis of the space-frequency joint characteristics on the DFT basis vector.
A communication device, comprising:

A processing unit, configured to determine a space-frequency joint characteristic common basis according to a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by a terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, the first frequency band and the second frequency band are both communication frequency bands between the terminal device and a network device, and the space-frequency joint characteristic common basis is used to determine a space-frequency joint characteristic basis of the first frequency band and a space-frequency joint characteristic basis of the second frequency band;

The communication unit is used to send information indicating the common basis of the space-frequency joint feature to the network device.
The device according to claim 21 is characterized in that the processing unit is specifically used to: determine a first space-frequency joint channel covariance matrix based on the first channel matrix, and determine a second space-frequency joint channel covariance matrix based on the second channel matrix; determine the space-frequency joint characteristic common basis based on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix.
The device according to claim 22, characterized in that the number of antenna ports N t1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports N t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of sub-bands B1 corresponding to the first frequency band is greater than or equal to the number of sub-bands B2 corresponding to the second frequency band;

The processing unit is specifically used for:

Performing positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, and determining a space-frequency joint channel statistical covariance matrix according to the summed matrices;

A singular matrix is determined according to the space-frequency joint channel statistical covariance matrix, and the first L columns of the singular matrix are selected as the space-frequency joint feature common basis, wherein L is less than or equal to the smaller value of B1*N t1 /2 and B2*N t2 /2.
The apparatus according to claim 23, characterized in that N t1 /2 is equal to N t2 /2, B1 is greater than B2, and the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix,

The processing unit is specifically used for:

The N t2 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are aligned and added in sequence with the N t1 /2 rows corresponding to each of the B2 subbands of the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix.
The apparatus according to claim 23, characterized in that N t1 /2 is greater than N t2 /2, and B1 is equal to B2, the first rule indicates that the second covariance matrix contains B2*B2 rows of N t2 /2 and columns of N t2 /2, and each square matrix contains row information and column information of 0 elements,

The processing unit is specifically used for:

Determine a third space-frequency joint channel covariance matrix, where the third space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of B2*B2 rows and N t2 /2 columns contained in the second covariance matrix according to the row information and column information indicated by the first rule;

The N t1 /2 rows corresponding to each of the B2 subbands in the third space-frequency joint channel covariance matrix are aligned and added in sequence with the N t1 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix.
The device according to claim 23, characterized in that N t1 /2 is greater than N t2 /2, and B1 is greater than B2,

The first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and row information and column information of adding 0 elements to each square matrix in the square matrix with B2*B2 rows and N t2 /2 columns contained in the second covariance matrix,

The processing unit is specifically used for:

Determine a fourth space-frequency joint channel covariance matrix, where the fourth space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of B2*B2 rows with N t2 /2 rows and N t2 /2 columns in the second covariance matrix according to the row information and column information indicated by the first rule;

The N t1 /2 rows corresponding to each of the B2 subbands in the fourth space-frequency joint channel covariance matrix are sequentially compared with the N t1 /2 rows corresponding to each of the B2 subbands in the first frequency band indicated by the first rule in the first space-frequency joint channel covariance matrix. The corresponding N t1 /2 rows are aligned and added in sequence.
The apparatus of claim 23, wherein N t1 /2 is equal to N t2 /2, and B1 is equal to B2,

The processing unit is specifically used for:

The N t1 /2 rows corresponding to each of the B2 subbands in the second space-frequency joint channel covariance matrix are sequentially aligned and added with the N t2 /2 rows corresponding to each of the B1 subbands in the first space-frequency joint channel covariance matrix.
The device according to any one of claims 23-27 is characterized in that the communication unit is also used to receive first indication information sent from the network device, the first indication information includes the first rule, and the first indication information is used to instruct the terminal device to perform positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.
The device according to any one of claims 23-27 is characterized in that the communication unit is also used to send second indication information to the network device, the second indication information includes the first rule, and the second indication information instructs the network device to process the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.
The device according to any one of claims 21-29 is characterized in that the information used to indicate the space-frequency joint characteristic common basis includes: the selected oversampling group, the index number of the discrete Fourier transform DFT basis vector corresponding to the oversampling group, and the projection coefficients of the space-frequency joint characteristic common basis on the DFT basis vector.
A communication device, comprising:

A communication unit, configured to receive information indicating a space-frequency joint feature common basis from a terminal device, wherein the space-frequency joint feature common basis is determined by the terminal device based on a first channel matrix and a second channel matrix, wherein the first channel matrix is a channel matrix of a first frequency band measured by the terminal device, the second channel matrix is a channel matrix of a second frequency band measured by the terminal device, and both the first frequency band and the second frequency band are communication frequency bands between a network device and the terminal device;

A processing unit is used to determine the space-frequency joint feature basis of the first frequency band and the space-frequency joint feature basis of the second frequency band according to the information used to indicate the common basis of the space-frequency joint feature.
The device according to claim 31 is characterized in that the space-frequency joint characteristic common basis is determined based on a first space-frequency joint channel covariance matrix and a second space-frequency joint channel covariance matrix, the first space-frequency joint channel covariance matrix is determined based on the first channel matrix, and the second space-frequency joint channel covariance matrix is determined based on the second space-frequency joint channel covariance matrix.
The device according to claim 32 is characterized in that the number of antenna ports N t1 /2 corresponding to a single polarization direction of the first frequency band is greater than or equal to the number of antenna ports N t2 /2 corresponding to a single polarization direction of the second frequency band, and the number of sub-bands B1 corresponding to the first frequency band is greater than or equal to the number of sub-bands B2 corresponding to the second frequency band,

The space-frequency joint characteristic common basis is composed of the first L columns of a singular matrix, the singular matrix is determined according to a space-frequency joint channel statistical covariance matrix, and the space-frequency joint channel statistical covariance matrix is obtained by performing a positional summation on the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to a first rule, wherein L is less than or equal to a smaller value of B1*N t1 /2 and B2*N t2 /2;

The processing unit is specifically used for:

Determining the space-frequency joint feature common basis as the space-frequency joint feature basis of the first frequency band;

According to the first rule, elements of the space-frequency joint feature common basis are selected to determine the space-frequency joint feature basis of the second frequency band.
The apparatus according to claim 33, characterized in that N t1 /2 is equal to N t2 /2, B1 is greater than B2, and the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix,

The processing unit is specifically used for:

Determine B2*N t2 /2 rows of the space-frequency joint characteristic common basis as the space-frequency joint characteristic basis of the second frequency band, wherein the B2*N t2 /2 rows are the N t1 /2 rows corresponding to each subband in the B2 subbands of the first frequency band indicated by the first rule in the space-frequency joint channel statistical covariance matrix.
The apparatus according to claim 33, characterized in that N t1 /2 is greater than N t2 /2, and B1 is equal to B2, the first rule indicates that the second covariance matrix contains B2*B2 rows of N t2 /2 and columns of N t2 /2, and each square matrix contains row information and column information of 0 elements,

The processing unit is specifically used for:

Extracting elements in B2*N t2 /2 rows in the space-frequency joint characteristic common basis, wherein the B2*N t2 /2 rows are the N t2 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band, wherein the third space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of zero elements to the square matrix containing B2 *B2 rows of N t2 /2 and N t2 /2 columns in the second covariance matrix according to the row information and column information indicated by the first rule, and the N t2 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band do not include the rows where the zero elements added to the N t1 /2 rows in the space-frequency joint channel statistical covariance matrix corresponding to each subband in the B2 subbands of the second frequency band are located;

The extracted elements are concatenated to obtain a space-frequency joint feature basis of the second frequency band.
The apparatus according to claim 33, characterized in that N t1 /2 is greater than N t2 /2, and B1 is greater than B2, the first rule indicates information of B2 subbands in B1 subbands of the first frequency band used to calculate the space-frequency joint channel statistical covariance matrix, and the second covariance matrix contains B2*B2 rows of N t2 /2, and columns of N t2 /2 square matrices, and row information and column information of each square matrix with 0 elements added,

The processing unit is specifically used for:

Determine the B2*N t1 /2 rows of the space-frequency joint feature common basis as the third space-frequency joint feature basis, wherein the B2*N t1 /2 rows are the rows corresponding to the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix, and the N t1 /2 rows corresponding to the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix correspond to the rows in the space-frequency joint channel statistical covariance matrix, and the fourth space-frequency joint channel covariance matrix is a matrix generated by adding N t1 /2-N t2 /2 rows and N t1 /2-N t2 /2 columns of 0 elements to each square matrix of the square matrix with B2*B2 rows of N t2 /2 and N t2 /2 columns in the second space-frequency joint channel covariance matrix according to the row information and column information indicated by the first rule;

Extracting elements in the B2*N t2 /2 rows in the third space-frequency joint characteristic common basis, the B2*N t2 /2 rows are the N t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the fourth space-frequency joint channel covariance matrix in the space-frequency joint channel statistical covariance matrix, and the N t2 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix do not include the rows where the 0 elements added in the N t1 /2 rows corresponding to each subband in the B2 subbands of the second frequency band in the space-frequency joint channel statistical covariance matrix are located;

The extracted elements are concatenated to obtain a space-frequency joint feature basis of the second frequency band.
The device according to claim 33, characterized in that N t1 /2 is equal to N t2 /2, and B1 is greater than B2,

The processing unit is specifically configured to determine the space-frequency joint feature common basis as the space-frequency joint feature basis of the second frequency band.
The apparatus according to any one of claims 33-37 is characterized in that the communication unit is also used to send a first indication information to the terminal device, the first indication information includes the first rule, and the first indication information is used to instruct the terminal device to perform a positional summation of the first space-frequency joint channel covariance matrix and the second space-frequency joint channel covariance matrix according to the first rule.
The device according to any one of claims 33-37 is characterized in that the communication unit is also used to receive a second indication information sent from the terminal device, the second indication information includes the first rule, and the second indication information instructs the network device to process the space-frequency joint characteristic common basis according to the first rule to obtain the space-frequency joint characteristic basis of the second frequency band.
The device according to any one of claims 31-39 is characterized in that the information used to indicate the common basis of the space-frequency joint characteristics includes: the selected oversampling group, the index number of the discrete Fourier transform DFT basis vector corresponding to the oversampling group, and the projection coefficients of the common basis of the space-frequency joint characteristics on the DFT basis vector.
A communication device, characterized in that the communication device comprises at least one processor and at least one memory, the at least one memory is used to store computer programs or instructions, and the at least one processor is used to execute the computer program or instructions in the memory, so that the method described in any one of claims 1 to 10 is executed, or the method described in any one of claims 11 to 20 is executed.
A computer-readable storage medium, characterized in that computer instructions are stored in the computer-readable storage medium. When the computer instructions are executed on a computer, the method as described in any one of claims 1 to 10 is executed, and the method as described in any one of claims 11 to 20 is executed.
A computer program product, characterized in that the computer program product includes a computer program code, and when the computer program code is run on a computer, the method according to any one of claims 1 to 10 is executed, and the method according to any one of claims 11 to 12 is executed. The method described in any one of 20 is performed.
A chip, characterized in that the chip includes a processor and a communication interface, and the processor reads instructions stored in a memory through the communication interface to execute the method as described in any one of claims 1 to 10, or executes the method as described in any one of claims 11 to 20.