Communication method and communication apparatus

Abstract

A communication method and a communication apparatus. The method comprises: acquiring a first basis, wherein the first basis is a channel basis of a first network device, the first basis is composed of L columns of basis vectors, and L is a positive integer; receiving a first reference signal sent by the first network device; determining a first superposition coefficient vector on the basis of the first reference signal and the first basis, wherein the first superposition coefficient vector comprises K superposition coefficients, and K is a positive integer less than or equal to L; and sending the first superposition coefficient vector and a first basis selection vector to a second network device, wherein the first superposition coefficient vector, the first basis selection vector and the first basis jointly represent a first channel matrix of the first network device, and the first basis selection vector comprises column indexes in the first basis corresponding to the K superposition coefficients.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 29, 2023, with application number 202311868106.9 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular, to a communication method and a communication device. Background Art

[0003] To improve system spectral efficiency, massive multi-input multi-output (MIMO) technology has been widely used. When using massive MIMO, network devices must precode data before sending it to end devices. The precoding method is primarily determined by downlink channel state information (CSI) fed back by the end devices.

[0004] In time division duplexing (TDD) systems, since the uplink and downlink channels use the same frequency band, channel reciprocity can be exploited to obtain the downlink CSI from the uplink channel, thereby determining the codebook for precoding. However, in frequency division duplexing (FDD) systems, since the separation between the uplink and downlink frequency bands is greater than the bandwidth, the uplink and downlink channels lack complete reciprocity, making it impossible to directly utilize uplink channel information for accurate downlink precoding. In traditional FDD systems, network equipment relies on users to provide CSI feedback. Figure 4 shows the basic flow chart for CSI measurement between network equipment and terminal devices. The network device first sends channel measurement configuration information to inform the terminal device of the channel measurement timing and behavior. The network device then sends a pilot signal to the terminal device. The terminal device measures the pilot signal sent by the network device to determine the CSI. The terminal device then provides CSI feedback to the network device. The network device transmits data based on the CSI feedback from the terminal device.

[0005] In contiguous MIMO networking scenarios, inter-cell interference poses a serious problem. If existing downlink channel reconstruction techniques are still used to obtain CSI, the obtained CSI will contain interference information, affecting precoding performance. Therefore, interference channel measurement is necessary. When measuring interference channels, the network device causing interference to the terminal device (referred to as the interfering network device) sends a pilot signal to the terminal device; the terminal device measures this pilot signal and then feeds back interference channel status information to the network device serving the terminal device (referred to as the serving network device).

[0006] However, measuring the interference channel will increase the long-period basis feedback overhead. Summary of the Invention

[0007] This application provides a communication method and apparatus that can transmit the first basis of an interfering station as prior information to a terminal device. When the terminal device provides interference channel feedback, it can only provide the position index and superposition coefficient of the interfering channel in the first basis, which helps reduce feedback overhead.

[0008] In a first aspect, a communication method is provided. The method may be executed by a terminal device, or may be executed by a module (such as a chip or circuit) of the terminal device, without limitation. For ease of description, the following description is based on an example of execution by a terminal device.

[0009] The method may include: obtaining a first basis, which is a channel basis of a first network device, and the first basis is composed of L column basis vectors, where L is a positive integer; receiving a first reference signal sent by the first network device; determining a first superposition coefficient vector based on the first reference signal and the first basis, where the first superposition coefficient vector includes K superposition coefficients, where K is a positive integer less than or equal to L; and sending the first superposition coefficient vector and a first basis selection vector to a second network device, where the first superposition coefficient vector, the first basis selection vector, and the first basis jointly represent a first channel matrix of the first network device, wherein the first basis selection vector includes K column indices, and the K column indices are indices of basis vectors corresponding to the K superposition coefficients in the first basis.

[0010] Through the above solution, the terminal device can obtain the first basis and the first reference signal sent by the interfering station (such as the first network device). Furthermore, based on the first basis, the terminal device can calculate and report the first superposition coefficient vector in combination with the channel estimation result of the first reference signal, eliminating the need to report long-period basis information and reducing the overhead of interference channel feedback. Furthermore, since the amount of interference channel feedback data is reduced, the amount of data fed back by the serving station to the interfering station is also reduced, reducing the latency of interference channel feedback.

[0011] In combination with the first aspect, in some implementation methods of the first aspect, determining a first superposition coefficient vector based on a first reference signal and a first basis includes: determining a second channel matrix based on the first reference signal; determining a second superposition coefficient vector based on the second channel matrix and the second basis, wherein the second basis is constructed by indexing the position of the first reference signal in the space-frequency domain in the corresponding row of the first basis, the dimension of the second channel matrix is ​​MN1×1, the dimension of the second basis is MN1×1, M is the number of antenna ports receiving the first reference signal, N is the number of frequency domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1; determining the first superposition coefficient vector based on the second superposition coefficient vector, the K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector.

[0012] Through the above scheme, the position index of the first reference signal in the space-frequency domain can be determined in the corresponding row of the first basis, so as to calculate the second superposition coefficient vector in combination with the channel estimation result of the reference signal, and further determine the first superposition coefficient vector with a smaller data volume for reporting, which can reduce the feedback overhead.

[0013] In combination with the first aspect, in some implementations of the first aspect, the smaller the value of L is, the smaller the density of the first reference signal is.

[0014] Through the above solution, the terminal device receives the first reference signal sent by the interfering station. The first reference signal may be a sparse reference signal, thereby reducing the reference signal overhead.

[0015] In combination with the first aspect, in some implementations of the first aspect, the method further includes: multiplying the first superposition coefficient vector and the third basis to obtain a first channel matrix, the third basis being composed of K position indices in the first basis selection vector corresponding to columns in the first basis.

[0016] Through the above scheme, the terminal device can determine the projection of the channel matrix based on the corresponding columns of the K position indices in the first basis, and can restore the channel matrix by combining the projection of the channel matrix with the first superposition coefficient vector, which is conducive to reducing computational overhead.

[0017] In combination with the first aspect, in some implementations of the first aspect, the method also includes: receiving a second reference signal sent by the first network device and a third reference signal sent by the second network device, the time domain resources, frequency domain resources and pilot sequences of the second reference signal and the third reference signal being the same; determining a third channel matrix based on the second reference signal and the third reference signal, the third channel matrix being the sum of the fourth channel matrix of the first network device and the first channel matrix of the second network device; and determining a fourth channel matrix of the second network device based on the first channel matrix and the third channel matrix.

[0018] Through the above scheme, the joint channel of the interference station and the service station (such as the second network device) can be determined in combination with the reference signal sent by the interference station and the service station. The joint channel is the sum of the fourth channel matrix of the first network device and the first channel matrix of the second network device, and the channel matrix from the service station to the terminal is determined in combination with the interference channel.

[0019] In combination with the first aspect, in some implementations of the first aspect, the method also includes: obtaining a fourth basis, the fourth basis is the channel basis of the second network device, the fourth basis is composed of R column basis vectors, R is a positive integer; determining a third superposition coefficient vector based on the fourth channel matrix and the fourth basis, the third superposition coefficient vector includes Q superposition coefficients, Q is a positive integer less than or equal to R; sending the third superposition coefficient vector and the second basis selection vector to the second network device, the third superposition coefficient vector, the second basis selection vector and the fourth basis jointly represent the fourth channel matrix of the second network device, the fourth channel matrix is ​​the channel matrix from the second network device to the terminal device, wherein the second basis selection vector includes Q column indices, and the Q column indices are indices of basis vectors corresponding to the Q superposition coefficients in the fourth basis.

[0020] Through the above solution, the terminal device can calculate the third superposition coefficient vector in combination with the first basis and the channel matrix from the service station to the terminal and report it, which is conducive to reducing the overhead of channel feedback.

[0021] In combination with the first aspect, in some implementations of the first aspect, the first basis, the second basis, or the fourth basis is a basis of the same type, and the basis of the same type is: a joint space-frequency basis, or a spatial basis and a frequency domain basis; wherein the joint space-frequency basis is a matrix constructed by one or more space-frequency domain basis vectors, the spatial basis is a matrix constructed by one or more spatial basis vectors, and the frequency domain basis is a matrix constructed by one or more frequency domain basis vectors.

[0022] In combination with the first aspect, in some implementations of the first aspect, the basis vectors are discrete Fourier transform DFT basis vectors, fast Fourier transform FFT basis vectors, oversampled DFT basis vectors, oversampled FFT basis vectors, or any one of vectors determined based on preset rules.

[0023] In a second aspect, a communication method is provided. The method may be executed by a second network device, or may be executed by a module (e.g., a chip or circuit) of the second network device, without limitation. For ease of description, the following description is based on an example of execution by a terminal device.

[0024] The method may include: sending a first basis and / or a fourth basis to a terminal device, where the first basis is a channel basis of a first network device, the first basis is composed of L-column basis vectors, and the fourth basis is a channel basis of a second network device, the fourth basis is composed of R-column basis vectors, L is a positive integer, and R is a positive integer; receiving a first superposition coefficient vector and a first basis selection vector, where the first superposition coefficient vector, the first basis selection vector, and the first basis jointly represent a first channel matrix of the first network device, wherein the first superposition coefficient vector includes K superposition coefficients, the first basis selection vector includes K column indices, the K column indices are indices of basis vectors corresponding to the K superposition coefficients in the first basis, and K is a positive integer less than or equal to L; and sending the first superposition coefficient vector and the first basis selection vector to the first network device.

[0025] Through the above solution, a channel basis is sent to the terminal device, allowing the terminal device to calculate and report, for example, a first superposition coefficient vector based on the first basis and the channel estimation result of the interfering station's reference signal. This helps reduce the overhead of interference channel feedback. Furthermore, since the amount of interference channel feedback data is reduced, the amount of data fed back by the serving station to the interfering station is also reduced, reducing the latency of interference channel feedback.

[0026] In combination with the second aspect, in some implementation methods of the second aspect, the K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector, the second superposition coefficient vector is determined based on the second channel matrix and the second basis, the second basis is constructed by indexing the position of the first reference signal sent by the first network device in the space-frequency domain in the corresponding row of the first basis, and the second channel matrix is ​​determined based on the first reference signal; wherein, the dimension of the second channel matrix is ​​MN1×1, the dimension of the second basis is MN1×L, M is the number of antenna ports sending the first reference signal, N1 is the number of frequency domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1.

[0027] Through the above scheme, the position index of the first reference signal in the space-frequency domain can be determined in the corresponding row of the first basis, so as to calculate the second superposition coefficient vector in combination with the channel estimation result of the reference signal, and further determine the first superposition coefficient vector with a smaller data volume and report it, which can reduce the feedback overhead.

[0028] In combination with the second aspect, in some implementations of the second aspect, the method further includes: receiving a first substrate from a core network device.

[0029] In combination with the second aspect, in some implementations of the second aspect, receiving a first channel substrate from a core network device includes: receiving a first channel map from a first network device of the core network device, the first channel map including a first substrate.

[0030] Through the above solution, the second network device can obtain the channel map of the interfering station and send it to the terminal device.

[0031] In combination with the second aspect, in some implementations of the second aspect, the method further includes: sending channel map request information to the core network device, where the channel map request information is used to request acquisition of the first channel map.

[0032] In combination with the second aspect, in some implementations of the second aspect, the method also includes: sending a third reference signal; receiving a third superposition coefficient vector and a second basis selection vector, the third superposition coefficient vector, the second basis selection vector and the fourth basis jointly representing a fourth channel matrix of the second network device, wherein the third superposition coefficient vector includes Q superposition coefficients, Q is a positive integer less than or equal to R, and the second basis selection vector includes Q column indices, and the Q column indices are indices of basis vectors corresponding to the Q superposition coefficients in the fourth basis; determining the fourth channel matrix based on the fourth basis, the third superposition coefficient vector and the second basis selection vector.

[0033] Through the above solution, the second network device can obtain the third superposition coefficient vector of the channel matrix from the service station to the terminal, and determine the channel matrix from the service station to the terminal in combination with the fourth basis.

[0034] In combination with the second aspect, in some implementation methods of the second aspect, a fourth channel matrix is ​​determined based on a fourth basis, a third superposition coefficient vector, and a second basis selection vector, including: multiplying the third superposition coefficient vector and a fifth basis to obtain the fourth channel matrix, the fifth basis being composed of corresponding columns of Q position indices in the second basis selection vector in the fourth basis.

[0035] Through the above scheme, the terminal device can determine the projection of the channel matrix based on the corresponding columns of the Q position indices on the fourth basis. The channel matrix can be restored by combining the projection of the channel matrix with the third superposition coefficient vector, which is conducive to reducing computational overhead.

[0036] In combination with the second aspect, in some implementations of the second aspect, the first basis, the second basis, the third basis, the fourth basis, or the fifth basis is a basis of the same type, and the basis of the same type is: a joint space-frequency basis, or a spatial domain basis and a frequency domain basis; wherein the joint space-frequency basis is a matrix constructed by one or more space-frequency domain basis vectors, the spatial domain basis is a matrix constructed by one or more spatial domain basis vectors, and the frequency domain basis is a matrix constructed by one or more frequency domain basis vectors.

[0037] In combination with the second aspect, in some implementations of the second aspect, the basis vectors are discrete Fourier transform DFT basis vectors, fast Fourier transform FFT basis vectors, oversampled DFT basis vectors, oversampled FFT basis vectors, or any one of vectors determined based on preset rules.

[0038] In a third aspect, a communication method is provided. The method may be executed by a first network device, or may be executed by a module (e.g., a chip or circuit) of the first network device, without limitation. For ease of description, the following description is based on an example of execution by a terminal device.

[0039] The method may include: obtaining a first basis, which is a channel basis of a first network device, and the first basis is composed of L column basis vectors, where L is a positive integer; sending a first reference signal to a terminal device; receiving a first superposition coefficient vector and a first basis selection vector, wherein the first superposition coefficient vector, the first basis selection vector and the first basis jointly represent a first channel matrix of the first network device, and the first channel matrix is ​​determined based on the first reference signal, wherein the first superposition coefficient vector includes K superposition coefficients, the first basis selection vector includes K column indices, and the K column indices are indices of basis vectors corresponding to the K superposition coefficients in the first basis, and K is a positive integer less than or equal to L; determining the first channel matrix based on the first basis, the first superposition coefficient and the first basis selection vector.

[0040] Through the above solution, a reference signal is sent to a terminal device. The terminal device can calculate and report a first superposition coefficient vector based on the first basis and the channel estimation result of the interfering station's reference signal. This helps reduce the overhead of interference channel feedback. Furthermore, since the amount of interference channel feedback data is reduced, the amount of data fed back by the serving station to the interfering station is also reduced, reducing the latency of interference channel feedback.

[0041] In combination with the third aspect, in some implementation methods of the third aspect, the K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector, and the second superposition coefficient vector is obtained based on the second channel matrix and the position index of the first reference signal sent by the first network device in the space-frequency domain constructed based on the corresponding rows of the first basis, and the second channel matrix is ​​determined based on the first reference signal; wherein, the dimension of the second channel matrix is ​​MN1×1, the dimension of the second basis is MN1×L, M is the number of antenna ports sending the first reference signal, N1 is the number of frequency domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1.

[0042] Through the above scheme, the position index of the first reference signal in the space-frequency domain can be determined in the corresponding row of the first basis, so as to calculate the second superposition coefficient vector in combination with the channel estimation result of the reference signal, and further determine the first superposition coefficient vector with a smaller data volume and report it, which can reduce the feedback overhead.

[0043] In combination with the third aspect, in some implementation methods of the third aspect, the first channel matrix is ​​determined based on the first basis, the first superposition coefficient and the first basis selection vector, including: multiplying the first superposition coefficient vector and the third basis to obtain the first channel matrix, and the third basis is composed of K position indexes in the first basis selection vector and the corresponding columns of the first basis.

[0044] Through the above scheme, the terminal device can determine the projection of the channel matrix based on the corresponding columns of the K position indices in the first basis, and can restore the channel matrix by combining the projection of the channel matrix with the first superposition coefficient vector, which is conducive to reducing computational overhead.

[0045] In combination with the third aspect, in some implementations of the third aspect, the smaller the value of L is, the smaller the density of the first reference signal is.

[0046] Through the above solution, the overhead of the reference signal is reduced.

[0047] In combination with the third aspect, in some implementations of the third aspect, the method further includes: sending a second reference signal to the terminal device, the second reference signal and a fourth channel matrix for determining the second network device.

[0048] In combination with the third aspect, in some implementation methods of the third aspect, the first basis, the second basis, or the third basis is a basis of the same type, and the basis of the same type is: a joint space-frequency basis, or a spatial domain basis and a frequency domain basis; wherein the joint space-frequency basis is a matrix constructed by one or more space-frequency domain basis vectors, the spatial domain basis is a matrix constructed by one or more spatial domain basis vectors, and the frequency domain basis is a matrix constructed by one or more frequency domain basis vectors.

[0049] In combination with the third aspect, in some implementations of the third aspect, the basis vectors are discrete Fourier transform DFT basis vectors, fast Fourier transform FFT basis vectors, oversampled DFT basis vectors, oversampled FFT basis vectors, or any one of vectors determined based on preset rules.

[0050] In a fourth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the first aspect or any possible implementation of the first aspect.

[0051] In a fifth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the second aspect or any possible implementation of the second aspect.

[0052] In a sixth aspect, a wireless communication device is provided, comprising modules or units for executing the method in the third aspect or any possible implementation of the third aspect.

[0053] In a seventh aspect, a communication device is provided, comprising a processor coupled to a memory, and configured to execute the method of any possible implementation of the first aspect. In one possible implementation, the memory is included in the communication device. In another possible implementation, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

[0054] In one implementation, the communication device is a terminal device. When the communication device is a terminal device, the communication interface may be a transceiver or an input / output interface. In one possible implementation, the transceiver may be a transceiver circuit. In another possible implementation, the input / output interface may be an input / output circuit.

[0055] In another implementation, the communication device is a chip or a chip system. When the communication device is a chip or a chip system, the communication interface can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The processor can also be embodied as a processing circuit or a logic circuit.

[0056] In an eighth aspect, a communication device is provided, comprising a processor coupled to a memory, and configured to execute the method of any possible implementation of the second aspect, or the method of any possible implementation of the third aspect. In one possible implementation, the memory is included in the communication device. In another possible implementation, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

[0057] In one implementation, the communication device is a network device. When the communication device is a network device, the communication interface may be a transceiver or an input / output interface. In one possible implementation, the transceiver may be a transceiver circuit. In another possible implementation, the input / output interface may be an input / output circuit.

[0058] In another implementation, the communication device is a chip or a chip system. When the communication device is a chip or a chip system, the communication interface can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The processor can also be embodied as a processing circuit or a logic circuit.

[0059] In a ninth aspect, a communication device is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive a signal via the input circuit and transmit a signal via the output circuit, so that the method of any one of the first to third aspects, and any possible implementation of any of the above aspects, is implemented.

[0060] In a specific implementation, the communication device may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, or various logic circuits. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to a transmitter and transmitted by the transmitter. The input circuit and the output circuit may be different circuits or the same circuit, in which case the circuit functions as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0061] In a tenth aspect, a processing device is provided, comprising a processor and a memory. The processor is configured to read instructions stored in the memory and to receive signals via a receiver and transmit signals via a transmitter to execute the method of any one of the first to third aspects, and any possible implementation of the aforementioned aspects.

[0062] In a possible implementation, there are one or more processors and one or more memories.

[0063] In a possible implementation, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

[0064] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or can be set on different chips. The embodiments of the present application do not limit the type of memory and the setting method of the memory and the processor.

[0065] It should be understood that related data interaction processes, such as sending indication information, can be the process of outputting indication information from the processor, and receiving capability information can be the process of receiving input capability information from the processor. Specifically, the output data of the processing can be output to the transmitter, and the input data received by the processor can come from the receiver. The transmitter and receiver can be collectively referred to as a transceiver.

[0066] The processor in the above aspects can be a chip, which can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. The memory can be integrated in the processor or located outside the processor and exist independently.

[0067] In the eleventh aspect, a computer program product is provided, which includes: a computer program (also referred to as code, or instructions), which, when run, enables a computer to execute any one of the first to third aspects, as well as any possible implementation method of the above aspects.

[0068] In the twelfth aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code, or instructions). When the computer program is run on a computer, the computer executes any one of the above-mentioned first to third aspects, as well as any possible implementation method of the above-mentioned aspects.

[0069] In the thirteenth aspect, a chip system is provided, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that a communication device equipped with the chip system executes any one of the first to third aspects above, as well as a method in any possible implementation of the above aspects.

[0070] Among them, the chip system may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0071] In a fourteenth aspect, a communication system is provided, comprising at least one of the aforementioned terminal device, the first network device, and the second network device. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] FIG1 is a schematic diagram of an example of a communication system to which the present application is applied.

[0073] FIG2 is a schematic diagram of a network element structure provided in this application.

[0074] FIG3 is a schematic diagram of a channel map.

[0075] FIG4 is a schematic diagram of a process of performing CSI measurement by a network device and a terminal.

[0076] FIG5 is a schematic diagram of an R16 codebook structure.

[0077] FIG6 is a schematic diagram showing an equivalent representation of a channel matrix H using a column vector.

[0078] FIG7 is a schematic diagram of matrix decomposition of a space-frequency joint channel h.

[0079] FIG8 is a schematic diagram of a space-frequency joint long-short cycle combined with codebook feedback process.

[0080] FIG9 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0081] FIG10 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0082] FIG11 is a schematic block diagram of a communication device provided in an embodiment of the present application.

[0083] FIG12 is a schematic block diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0084] The technical solution in this application will be described below with reference to the accompanying drawings.

[0085] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR) and future communication systems, vehicle-to-other devices (V2X), where V2X may include vehicle to network (V2N), vehicle to vehicle (V2V), vehicle to infrastructure (V2I), vehicle to pedestrian (V2P), etc., long term evolution-vehicle (LTE-V), Internet of Vehicles, machine type communication (MTC), Internet of Things (IoT), etc. things, IoT), long term evolution-machine (LTE-M), machine to machine (M2M), etc.

[0086] Figure 1 is a schematic diagram of a communication system provided by an embodiment of the present application. As shown in Figure 1 , the communication system 100 includes at least one terminal device, such as the terminal device 110 shown in Figure 1 ; the communication system 100 may also include at least one network device, such as the network device 120 and / or the network device 130 shown in Figure 1 . The terminal device 110 and the network devices 120 / 130 can communicate via a wireless link and thereby exchange information. It will be understood that the terminal device and the network device may also be referred to as a communication device or a communication apparatus.

[0087] A network device is a network-side device with wireless transceiver functions. A network device may be a device in a radio access network (RAN) that provides wireless communication functions for terminal devices, and is called a RAN device. For example, the network device may be a base station, an evolved NodeB (eNodeB), a next-generation NodeB (gNB) in a 5G mobile communication system, a base station that has been subsequently evolved by 3GPP, a transmission reception point (TRP), an access node in a WiFi system, a wireless relay node, a wireless backhaul node, etc. In communication systems using different radio access technologies (RAT), the names of devices with base station functions may be different. For example, in an LTE system, it may be called an eNB or eNodeB, and in a 5G system or NR system, it may be called a gNB. This application does not limit the specific name of the base station. The network device may include one or more co-located or non-co-located transmission and reception points. For another example, the network device may include at least one of the following items: one or more centralized units (CU), one or more distributed units (DU), and one or more radio units (RU). In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, the radio access network may also be an open radio access network (O-RAN) architecture. In the ORAN system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. Any of the CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. Exemplarily, the functions of the CU may be implemented by one entity or different entities. For example, the functions of the CU are further divided, that is, the control plane and the user plane are separated and implemented through different entities, namely the control plane CU entity (i.e., CU-CP entity) and the user plane CU entity (i.e., CU-UP entity). The CU-CP entity and the CU-UP entity can be coupled with the DU to jointly complete the functions of the access network device.For example, the CU is responsible for processing non-real-time protocols and services, implementing the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers. The DU is responsible for processing physical layer protocols and real-time services, implementing the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. In this way, some functions of the wireless access network device can be implemented through multiple network function entities. These network function entities can be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (for example, a cloud platform). The network device may also include an active antenna unit (AAU). The AAU implements some physical layer processing functions, RF processing, and related functions of the active antenna. Since RRC layer information will eventually become PHY layer information, or be converted from PHY layer information, in this architecture, high-layer signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by the DU+AAU. It can be understood that the network device can be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU can be divided into a network device in the access network (radio access network, RAN), or the CU can be divided into a network device in the core network (core network, CN), and this application does not limit this. For example, in the vehicle to everything (V2X) technology, the access network device can be a road side unit (RSU). The multiple access network devices in the communication system can be base stations of the same type or different types. The base station can communicate with the terminal device or communicate with the terminal device through a relay station. In an embodiment of the present application, the device for realizing the function of the network device can be the network device itself, or it can be a device that can support the network device to realize the function, such as a chip system or a combination device or component that can realize the function of the access network device, and the device can be installed in the network device. In an embodiment of the present application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0088] A terminal device is a user-side device with wireless transceiver capabilities. It can be a fixed device, mobile device, handheld device (such as a mobile phone), wearable device, in-vehicle device, or a wireless device built into any of the above devices (such as a communication module, modem, or chip system). Terminal devices are used to connect people, objects, and machines, and can be used in a wide range of scenarios, such as cellular communications, device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, machine-to-machine / machine-type communications (M2M / MTC) communications, the Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical care, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, drones, robots, and other scenarios. Exemplarily, the terminal device can be a handheld terminal in cellular communication, a communication device in D2D, an IoT device in MTC, a surveillance camera in intelligent transportation and smart cities, or a communication device on a drone, etc. The terminal device may sometimes be referred to as user equipment (UE), user terminal, user device, user unit, user station, terminal, access terminal, access station, UE station, remote station, mobile device or wireless communication device, etc. The terminal device may also be a terminal device in an IoT system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. In an embodiment of the present application, IoT technology can achieve massive connections, deep coverage, and terminal power saving through, for example, narrowband (NB) technology. In an embodiment of the present application, the device for realizing the function of the terminal device may be a terminal device, or a device that can support the terminal device to realize the function, such as a chip system or a combination device or component that can realize the function of the terminal device. The device can be installed in the terminal device.

[0089] The network equipment and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; they can also be deployed in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the scenarios in which the network equipment and terminal devices are located.

[0090] For example, the communication system 100 may further include an application function (AF) network element, which is a control plane network function provided by the operator network and is used to provide application layer information; the communication system 100 may further include a session management function (SMF) network element, which is a control plane network function provided by the operator network. In the embodiment of the present application, when the communication system 100 includes the AF network element and the SMF network element, the AF can send service-related information to the network device via the SMF.

[0091] Optionally, the network element structure involved in this application is shown in Figure 2, which mainly includes the following network elements and modules:

[0092] (1) RRC signaling interaction module: The module used by the base station and the terminal to send and receive RRC signaling.

[0093] (2) Multimedia access management / control (MAC) signaling interaction module: The module used by base stations and terminals to send and receive MAC control element (MAC-CE) signaling.

[0094] (3) Physical layer (PHY) signaling and data interaction module: The module used by the base station and the terminal to send and receive uplink / downlink control signaling (such as physical downlink control channel (PDCCH), physical uplink control channel (PUCCH)), and uplink / downlink data (such as data transmitted on physical downlink shared channel (PDSCH), data transmitted on physical uplink shared channel (PUSCH)).

[0095] (4) The base station and AMF communicate through the NG-C interface. The AMF is equivalent to a router for the base station to communicate with the location management function (LMF) / map management function (MMF). The LMF implements the UE location estimation, and the map construction process is completed in the LMF / MMF. The AMF and LMF / MMF communicate through the NLs interface.

[0096] It can be understood that in this application, PDSCH, PDCCH, PUSCH and PUCCH are only examples of downlink data channels, downlink control channels, uplink data channels and uplink control channels, respectively. In different systems and different scenarios, data channels and control channels may have different names, and this application does not limit this.

[0097] To facilitate understanding of this application, some concepts involved in this application are introduced below.

[0098] 1. Channel map:

[0099] A channel map is defined as a database that stores location-based channel characteristics, including but not limited to the channel statistical covariance matrix, angular spectrum, delay spectrum, and path loss. For example, Figure 3 shows a schematic diagram of a channel map. In this channel map, the physical cell is divided into a two-dimensional grid (each square in Figure 3 is a grid point). Each grid point stores a number of channel characteristics (such as the channel statistical covariance matrix, angular spectrum, delay spectrum, and path loss) in the form of a matrix, vector, or scalar.

[0100] Among them, the commonly used channel map construction method is to build a database based on historical measurement data and establish a mapping relationship between location information and channel characteristics. However, historical measurement data has limitations. For example, historical measurement data is usually based on channel characteristics at known locations, and the channel characteristics at unknown locations are supplemented by interpolation methods to obtain the channel map of the entire cell. With the development of digital twin technology, channel maps can be obtained through channel twin technology. For example, a computer can combine a priori environmental maps (such as environmental information obtained by measurement) and use electromagnetic simulation calculations to simulate the reflection, diffraction, and scattering characteristics of communication multipaths, thereby obtaining deterministic channels for constructing channel maps.

[0101] 2. Channel map-assisted communication technology:

[0102] With the increase in system bandwidth, the increase in terminal antennas, the increase in network load, the surge in wireless channel dimensions (for example, the wireless channel dimensions can be expanded to multiple dimensions such as the spatial domain, spatial frequency domain, and frequency domain), and the limited pilot measurement resources, high-precision measurement of wireless channels faces huge challenges. Accurate measurement of wireless channels is the cornerstone of mobile communication network research and is crucial to the design, analysis, and optimization of wireless communication networks. However, traditional wireless channel measurement methods based on reference signals (such as pilot symbols) are difficult to meet the needs of technological development such as large bandwidth and multiple antennas. In order to solve the problem of limited reference signal measurement resources in wireless communication systems, channel maps can be used to achieve channel measurement with low pilot overhead; for example, the channel covariance matrix of a specific location is provided by the channel map, and the sounding reference signal (SRS) overhead is assisted reduced based on the channel covariance matrix.

[0103] 3. Downlink channel reconstruction technology:

[0104] In 5G communication systems, the use of massive multiple input, multiple output (Massive MIMO) technology helps improve the system's spectral efficiency. When using MIMO technology, network devices must precode signals based on channel state information (CSI) when sending data to terminal devices.

[0105] In a time division duplexing (TDD) system, downlink CSI can be obtained based on channel reciprocity, for example, by estimating the downlink channel by sending uplink SRS data. As the number of users increases and the load continues to increase, SRS transmission in large bandwidth scenarios may lead to insufficient SRS resources and severe channel aging.

[0106] In frequency division duplexing (FDD) systems, due to the large frequency separation between uplink and downlink channels, the uplink and downlink channels do not directly exchange with each other, making it impossible to use uplink channel information for accurate downlink precoding. In FDD systems, users are required to provide downlink channel CSI feedback to the base station.

[0107] For example, FIG4 is a schematic diagram of a process of performing CSI measurement by a network device and a terminal, which may include the following steps:

[0108] Step 1: The network device sends channel measurement configuration information to the terminal. The channel measurement configuration information is used to configure the channel measurement, for example, to indicate the channel measurement time to the terminal.

[0109] Step 2: The network device sends a channel state information reference signal (CSI-RS) to the terminal. This pilot is used for channel measurement. For example, the terminal receives the CSI-RS and performs measurements based on the CSI-RS to obtain CSI feedback information. Optionally, the CSI-RS can also be called a CSI-RS pilot.

[0110] Step 3: The terminal sends channel state information to the network device. For example, the terminal sends channel state information such as channel rank indicator (RI), channel quality indicator (CQI), and precoding matrix indicator (PMI) to the network device.

[0111] Step 4: The network device sends data to the terminal based on the CSI. The network device determines the precoding information for the service data based on the CSI fed back by the terminal, thereby transmitting the service data.

[0112] Optionally, channel state information (CSI) includes information used to describe the channel properties of the communication link reported by the receiving device to the transmitting device in a wireless communication system. CSI may include, but is not limited to, precoding matrix indication (PMI), rank indication (RI), channel quality indication (CQI), CSI-RS resource indicator (CSI-RS resource indicator, CRI) and layer indicator (layer indicator, LI), etc. It should be understood that the specific content of the CSI listed above is only an example 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, which is not limited in this application.

[0113] 4. R16 codebook solution for channel reconstruction based on reference signals:

[0114] For example, the R16 codebook is a dual-domain compression codebook in the spatial domain and the frequency domain. It compresses the channels of all subbands in the frequency domain. The codebook structure satisfies formula (1):

[0115] in, is the spatial compression matrix, is the combination coefficient matrix, is the frequency domain compression matrix, N1 and N2 are the number of horizontal and vertical antenna ports of the base station, L is the number of spatial basis, and M is the number of frequency domain basis. For example, Figure 5 is a schematic diagram of an R16 codebook structure, which shows each matrix and its dimensions. Optionally, spatial-frequency dual-domain compression refers to quantizing the channel using both spatial and frequency sparsity to reduce the number of weighting coefficients required to be reported, thereby achieving channel matrix compression.

[0116] However, the R16 codebook only utilizes the sparse characteristics of the channel in the angle-delay domain, that is, the spatial information correlation characteristics on different subbands for feedback and compression. For example, it is necessary to feedback the spatial domain, frequency domain basis and combination coefficients, which results in a large feedback overhead. And because the basis needs to be reported, the protocol stipulates that both the spatial domain and frequency domain basis are discrete Fourier transform (DFT) codebooks, which limits the sparsity of the combination coefficient matrix W2. In addition, in actual channels, especially in scenarios where the channel propagation environment changes slowly, the basis changes very slowly and can be fed back over a long period. However, R16 does not support reporting the basis and combination coefficients at different periods.

[0117] 5. R18 codebook solution for channel reconstruction based on reference signals:

[0118] To achieve a sparse representation of the channel in the space-frequency domain, fully exploit the channel's sparse characteristics, and consider the inconsistent temporal variations of different channel characteristics. For example, the path angle-delay information (joint space-frequency basis) changes slowly, while the path superposition coefficient (the superposition coefficient corresponding to the basis) changes rapidly. The R18 codebook scheme for channel reconstruction based on a reference signal is designed with a combined long- and short-cycle codebook feedback method, which helps reduce feedback overhead. For example, the following describes two scenarios: joint space-frequency compression and feedback, and independent space-frequency compression and feedback.

[0119] Case 1: Joint space-frequency compression and feedback:

[0120] Taking the downlink channel as an example, assuming that the terminal has a single antenna, the channel matrix of the terminal satisfies formula (2):

[0121] in, is the spatial compression matrix, is the frequency domain compression matrix, is a combination coefficient matrix (which is a diagonal matrix), M is the number of base station antennas, L is the number of channel multipaths, and N is the number of frequency units (for example, a frequency unit is a subcarrier or a resource element (RE) or a resource block (RB) or a resource group (RBG) or a sub-band). For example, FIG6 is a schematic diagram of an equivalent representation of a channel matrix H using a column vector. It can be seen that the channels H1, H2, ..., H represented by the matrix in the spatial-frequency domain shown in FIG6 are t The column vectors h1, h2, ..., h in the space-frequency domain can be used t Equivalent representation. The equivalent column vector satisfies formula (3):

[0122] Where diag(C) represents the column vector consisting of the diagonal elements of matrix C ⊙ represents the Khatri-Rao product. For example, a l is the lth column of A, is the Kronecker product, b l is the lth column of B, where l is an integer greater than 0. * The lth (i=1, ..., N) column of ⊙S can satisfy formula (4):

[0123] in, represents the Kronecker product, where [:,l] represents the lth column of the matrix. The above operation can represent the channel represented by a matrix in the space-frequency domain using a space-frequency column vector.

[0124] Among them, for the channel h represented by the column vector, its statistical covariance matrix satisfies formula (5):

[0125] in, Indicates the expectation of random numbers / matrices, U is the covariance matrix R h The matrix of the eigenvectors of U, the i-th column is R h The i-th eigenvector of , whose corresponding eigenvalue is the i-th element on the diagonal of the diagonal matrix Λ, the eigenvalue corresponding to each column of U is the element on the diagonal of the diagonal matrix Λ, and the elements on the diagonal of Λ are arranged from large to small. The average covariance matrix between polarizations satisfies formula (6):

[0126] Among them, h + is the channel corresponding to positive polarization, h -is the channel corresponding to negative polarization, is the mean covariance matrix The matrix of eigenvectors, The i-th column of The i-th eigenvector of The i-th element on the diagonal of The eigenvalue corresponding to each column is a diagonal matrix The elements on the diagonal of , and The elements on the diagonal are arranged from large to small, then the instantaneous channel satisfies formula (7):

[0127] Among them, U p is the matrix composed of the first P columns of the basis U. The channel has a sparse characteristic in the angular delay domain (i.e. Only some elements in the θ are non-zero or have large values), and the angular delay changes slowly (i.e. at different times h1, h2...h t ,U can be considered to be basically unchanged or change slowly, and Then it changes with time). In addition, using KL decomposition (Karhunen-Loeve decomposition), when the eigenvectors corresponding to the P largest eigenvalues ​​of the matrix Rh (i.e., the first P columns U p ) is used to expand h, the truncated statistical mean square error is the smallest. Considering that the statistical covariance matrix can be approximated by the statistical covariance matrix after polarization averaging, the instantaneous channel h satisfies formula (8):

[0128] in, for Before The matrix consists of columns, In designing a CSI feedback solution, a longer period can be used to Provide quantitative feedback in a short-term or non-periodic manner Provide quantitative feedback.

[0129] For example, a specific CSI compression reporting solution includes the following steps:

[0130] S1: UE performs space-frequency joint covariance matrix statistics on the downlink channel and performs inter-polarization averaging to obtain right Perform singular value decomposition (SVD) or eigendecomposition to obtain the matrix of eigenvectors UE pair matrix Truncate and select the one with the largest energy The corresponding eigenvalues Column matrix Contains most of the channel energy (the choice of P can be determined by the UE, or the gNB specifies an optional range and then the UE selects it).

[0131] S2: UE uses the DFT codebook to construct a matrix of statistical eigenvectors Make an approximation, that is, find W f , W s , C1 makes or Where W f With W s is a submatrix composed of some columns of the oversampled DFT matrix, representing the beam / basis vectors in the frequency domain and spatial domain respectively; C1 is The projection on the quantization matrix W1 can correct W1 into a statistical feature matrix The W calculated in this step f , W s , C1 is reported to the base station with a long period (optional, "long period" is to distinguish it from the "short period" in the following text, and it does not necessarily emphasize that the reporting period of these matrices is the same, because the time change scale of each matrix may be different, for example, the rate of change of C1 over time is more likely to be higher than W f , W s faster, and thus can have a different granularity of feedback cycles).

[0132] S3: The UE calculates the codebook C2 to be fed back based on the instantaneous channel h and W1C1 obtained in S2. C2 can be the projection of the instantaneous channel h on W1C1, that is, C2 = (W1C1) H h; or C2 can be calculated in other ways (for example, when the columns of W1C1 are not orthogonal, W1C1 needs to be orthogonalized). The UE feeds back C2 to the base station in a short period or aperiodically for reconstructing the downlink channel.

[0133] The above CSI compression reporting scheme is mapped to the codebook form to satisfy formula (9):

[0134] Where ⊙ represents the KR (Khatri-Rao) product. For example, Figure 7 shows a matrix decomposition diagram of a space-frequency joint channel h, where h is the space-frequency joint channel, M is the number of base station antennas (dual-polarization array), and N is the number of frequency units (subcarrier granularity or RB granularity or RBG granularity or subband granularity). Since W f , W s , C1 is used to quantify the approximation Therefore, 2K≥P is satisfied, K is the matrix W s The number of columns. is the DFT basis for quantizing the joint space-frequency basis.

[0135] Case 2: Space-frequency independent compression and feedback:

[0136] Taking the downlink channel as an example, assuming that the terminal has a single antenna, the channel matrix of the terminal satisfies formula (10): H≈S′C1C2C3F′ H (10)

[0137] in, is the spatial basis, which is a matrix composed of B spatial vectors; is the frequency domain basis, which is a matrix composed of F frequency domain vectors. is the first superposition coefficient matrix, which represents the coefficient matrix composed of multiple groups of spatial vector coefficients; is a second superposition coefficient matrix, representing a coefficient matrix composed of weighting coefficients corresponding to a set of space-frequency vectors composed of each space-domain vector in the B space-domain vectors and each frequency-domain vector in the F frequency-domain vectors; is the third superposition coefficient matrix, which represents a matrix composed of multiple sets of frequency domain vector coefficients. B is the number of spatial domain vectors determined by the network device or terminal; K S represents the number of weighted coefficients corresponding to each spatial domain vector; D represents the number of weighted coefficients corresponding to each frequency domain vector; and F is the number of frequency domain vectors determined by the network device or terminal.

[0138] Optionally, the spatial domain vector may also be called a beam vector, a spatial beam basis vector, or a spatial basis vector. The length of the spatial domain vector may be the number M of transmit antenna ports in a polarization direction, where M is a positive integer greater than 1. For example, if the spatial domain vector is a column vector or a row vector of length M, then the M column vectors or row vectors correspond to M transmit antenna ports, respectively, and this application does not limit this. Each element in the spatial domain vector may represent the weight of each antenna port. Based on the weights of each antenna port represented by each element in the spatial domain vector, the signals of each antenna port are linearly superimposed to form an area with a strong signal in a certain direction or certain directions in space. Optionally, the spatial domain vector may be determined based on a DFT vector. In other words, the spatial domain vector may be a DFT vector. The spatial domain vector may be, for example, a DFT vector defined in a type II codebook in the 3rd Generation Partnership Project (3GPP) technical specification TS 38.214 version 15 (release 15, R15).

[0139] Optionally, a frequency domain vector (frequency domain vector), also known as a frequency domain basis vector, is a vector used to represent the variation pattern of the channel in the frequency domain. A frequency domain vector can represent a variation pattern. Since a signal can reach the receiving antenna from the transmitting antenna through multiple paths when transmitted through a wireless channel. Multipath delay causes frequency selective fading, which is a change in the frequency domain channel. Therefore, different frequency domain vectors can be used to represent the variation pattern of the channel in the frequency domain caused by delays on different transmission paths. The length of the frequency domain vector can be determined by the number of frequency domain units to be reported configured by the network side in the reporting bandwidth, or it can be a protocol predefined value. This application does not limit the length of the frequency domain vector. Among them, the reporting bandwidth can, for example, refer to the CSI reporting bandwidth (CSI-ReportingBand) carried in the CSI reporting configuration in the high-level signaling (such as RRC message). The length of the frequency domain vector can be denoted as N, where N is a positive integer greater than 1. The frequency domain vector can, for example, be a column vector or row vector whose length includes N. This application does not limit it.

[0140] Optionally, a joint space-frequency basis can represent common characteristics of the spatial and frequency domains; for example, the joint space-frequency basis is a matrix constructed from one or more space-frequency basis vectors. The space-frequency basis vectors can represent the channel's frequency-domain variation pattern and the signal characteristics in one or more spatial directions. For example, the characteristics of space-domain and frequency-domain vectors can be described above and will not be repeated here.

[0141] Corresponding to the channel decomposition method shown in formula (10), the mapping to the codebook form satisfies formula (11):

[0142] in, It is the spatial basis of the downlink channel determined by the network equipment or terminal. It is the frequency domain basis of the downlink channel determined by the network device or terminal. S The calculation method satisfies formulas (12) and (13): U S =W S C1(13)

[0143] in, is the spatial statistical covariance matrix of H, R S The matrix composed of the eigenvectors of s The eigenvalue corresponding to each column is a diagonal matrix The elements on the diagonal of , and Λ S The elements on the diagonal are arranged from large to small. Indicates the expectation of random numbers / matrices. W f The calculation method is to satisfy formulas (14) and (15):

[0144] in, is the frequency domain statistical covariance matrix of H, R F The matrix composed of the eigenvectors of F The eigenvalue corresponding to each column is a diagonal matrix The elements on the diagonal of , and Λ F The elements on the diagonal are arranged from largest to smallest.

[0145] For example, Figure 8 is a schematic diagram of a space-frequency joint long-short cycle combined with codebook feedback process. For example, assuming that the base station configuration includes 64T dual-polarized antennas, 50RB, and uses 64 DFT column vectors to approximate The number of columns is 13, Long-cycle feedback W1C1, period T L ; Short-cycle feedback C2, period is T S During each long-period baseline feedback, ignoring the amount of feedback required for W1, the 64 × 13 = 832 coefficients that make up C1 must be fed back. This indicates that the combined space-frequency, long- and short-period codebook feedback overhead is significant. Furthermore, the base station must be configured with a 32-port CSI-RS for channel information measurement, resulting in significant pilot overhead. This increases dramatically with the number of antennas and frequency bands.

[0146] In contiguous MIMO networking scenarios, inter-cell interference poses a serious problem. If existing downlink channel reconstruction techniques are still used to obtain CSI, the obtained CSI will contain interference information, affecting precoding performance. Therefore, interference channel measurement is necessary. When measuring interference channels, a network device causing interference to a terminal device (called an interfering station) sends a pilot signal to the terminal device. The terminal device measures this pilot signal and then provides feedback on the interference channel status to the network device serving the terminal device (called a serving station).

[0147] However, measuring the interference channel increases the overhead of reference signal resources and long-period basis feedback. Furthermore, the serving station and the interfering station need to exchange a large amount of interference channel information, resulting in significant interaction delays.

[0148] In order to solve the above problems, the present application provides a variety of communication methods, using the regional channel basis provided by the channel map as prior information (which can be a space-frequency basis U, a spatial basis U S , frequency domain basis U F , or it can be the spatial compression matrix W s, frequency domain compression matrix W f , not limited in this application), sends the interfering station's joint space-frequency basis U to the UE, and also sends a sparse CSI-RS. After receiving the sparse CSI-RS sent by the interfering station, the UE calculates the superposition coefficient C2 and feeds it back. It also updates and feeds back the column index value of the joint space-frequency basis to reduce the overhead of inter-device interaction resources and the latency of inter-station interaction during interference channel measurement.

[0149] It should be understood that the description of the specific scenarios in the embodiments of the present application is only an example. In addition to being applicable to the application scenarios described above, the methods provided in the embodiments of the present application are also applicable to application scenarios with similar problems.

[0150] The following describes in detail various communication methods provided in the embodiments of the present application with reference to the accompanying drawings.

[0151] It should be understood that the step numbers in the embodiments of the present application are for illustration only and do not limit the order in which the steps occur.

[0152] For ease of understanding and explanation, the following describes the communication method of the embodiment of the present application by taking the interaction between the terminal device and the network device as an example, but this should not constitute any limitation on the execution subject of the communication method of the embodiment of the present application. For example, the method performed by the terminal device can also be performed by a module (such as a circuit, a chip or a chip system, etc.) of the terminal device, and can also be implemented by a logical node, a logical module or software that can realize all or part of the terminal device function. The method performed by the network device can also be performed by a module (such as a circuit, a chip or a chip system, etc.) of the network device, and can also be implemented by a logical node, a logical module or software that can realize all or part of the network device function.

[0153] FIG9 shows a communication method 900 provided in the present application, which method 900 includes at least part of the method shown in FIG9 .

[0154] S910, the terminal device obtains a first basis, which is a channel basis of a first network device (optionally, the first network device may be an interference station of the terminal device), wherein the first basis is composed of L columns of basis vectors, where L is a positive integer.

[0155] Optionally, the terminal device acquires the first basis, including: the terminal device receives the first basis sent by a second network device (optionally, the first network device may be a service station of the terminal device), and correspondingly, the second network device sends the first basis to the terminal device.

[0156] It should be noted that the first basis in this application is the regional-level channel basis (prior information) provided by the channel map. The second network device can obtain the channel basis without quantization loss of the first network device based on the channel map, and send the channel basis without quantization loss to the terminal device, which is conducive to improving the CSI reconstruction accuracy.

[0157] In one possible implementation, the second network device sends a first basis to the terminal device, which can be understood as: the second network device sends indication information of the first basis to the terminal device, where the indication information of the first basis indicates the projection coefficients of the first basis on the quantization basis of the first basis and the column index of the quantization basis of the first basis; the first basis is composed of L column basis vectors, where L is a positive integer. For example, the quantization basis of the first basis is any one of a DFT codebook, a fast Fourier transform (FFT) codebook, an oversampled DFT codebook, an oversampled FFT codebook, or a codebook determined based on a preset rule, which is not limited in this application.

[0158] Among them, the basis vector is determined based on the quantization basis. For example, the basis vector is any one of the DFT basis vector (DFT basis vector is a vector determined based on the DFT codebook), the FFT basis vector (FFT basis vector is a vector determined based on the FFT codebook), the oversampled DFT basis vector (the oversampled DFT basis vector is a vector determined based on the oversampled DFT codebook), the oversampled FFT basis vector (the oversampled FFT basis vector is a vector determined based on the oversampled FFT codebook), or a vector determined based on a preset rule. Assuming that one or more basis vectors are one or more DFT basis vectors, the first basis is a matrix composed of L columns of DFT basis vectors selected from the one or more DFT basis vectors (that is, the elements in the first basis meet the preset rules and have relevant characteristics).

[0159] The column index of the quantization basis of the first basis includes the index of the basis vectors constituting the first basis. For example, assuming that the first basis is obtained by quantizing and projecting the quantization basis of the first basis, for example, the quantization basis of the first basis can be a DFT codebook, then the first basis is obtained by quantizing and projecting the DFT codebook. However, the DFT codebook may have multiple DFT basis vectors arranged in sequence. Assuming that the first, third, and fifth DFT basis vectors are selected to construct the first basis, the column index of the quantization basis of the first basis is {1, 3, 5}.

[0160] Optionally, the first basis is a space-frequency joint basis, or a space domain basis and a frequency domain basis. For example, assuming that the first basis is a space-frequency joint basis U, and the quantization basis of the first basis is a DFT codebook, the indication information of the first basis indicates the projection coefficient of the space-frequency joint basis U in the DFT codebook and the column index of the DFT codebook. It should be noted that the basis in this application can also be referred to as a codebook. For example, the first basis can also be referred to as a first codebook, the second basis can also be referred to as a second codebook, and so on. This application is not limited thereto.

[0161] Optionally, specific implementations of the indication information of the first base include the following:

[0162] (1) Case 1: The indication information of the first basis includes the first basis. That is, the second network device directly sends the first basis of the first network device to the terminal device. For example, assuming that the first basis is the space-frequency joint basis U, the second network device uses PDCCH / PDSCH to send the space-frequency joint basis corresponding to the terminal device to the terminal device. M is the number of antennas of the first network device, L is the number of paths, and N is the number of frequency units (for example, a frequency unit is a subcarrier, RB, RBG, or subband). It should be noted that the values ​​in the first basis can be in complex form. In this case, the complex values ​​need to be subjected to amplitude and phase quantization processing. The second network device can obtain and send the first basis after the amplitude and phase quantization processing.

[0163] (2) Case 2: The indication information of the first basis includes the projection coefficient of the first basis on the quantization basis of the first basis and the column index of the quantization basis of the first basis. That is, the second network device indirectly indicates the first basis to the terminal device. For example, assuming that the first basis is a space-frequency joint basis U, the second network device can use the quantization basis B of the first basis constructed by one or more basis vectors to quantize the space-frequency joint basis U, and the quantization process satisfies formula (16): U = B × C 13 (16)

[0164] Where B represents the quantized basis of the first basis, C 13 Represents the projection coefficient of the first basis on the quantized basis of the first basis, C 13 The role of is similar to the coefficient W1C1 above. Therefore, the indication information of the first basis includes the column index of the quantization basis of the first basis (indicating the basis vector used for quantizing the space-frequency joint basis U) and C f3 For another example, suppose the first basis is the spatial basis U S and frequency domain basis U F When , you can refer to the description of the space-frequency independent compression and feedback process described in the first part of the previous article, such as the spatial basis U S Satisfy formula (13), use WS Perform quantization processing; frequency domain basis U F Satisfy formula (15), use W f Perform quantification processing.

[0165] Optionally, the second network device can use PDCCH / PDSCH to send the projection coefficient of the first basis on the quantization basis of the first basis and the column index of the quantization basis of the first basis to the terminal device; correspondingly, the terminal device receives the projection coefficient of the first basis on the quantization basis of the first basis and the column index of the quantization basis of the first basis, so that the space-frequency joint basis U can be restored in combination with the quantization basis B of the first basis. Optionally, the quantization basis B of the first basis is known and the same to the terminal device and the second network device. For example, the quantization basis B of the first basis can be a DFT codebook. Optionally, the indication overhead of case two is lower than the indication overhead of case one, but both the terminal device and the second network device need to preset (such as pre-store) the quantization basis B of the first basis.

[0166] Optionally, before S910, the following steps are further included:

[0167] The second network device sends a channel map request message to the core network device, where the channel map request message is used to request the first channel map of the first network device, thereby obtaining the first basis of the first network device corresponding to the terminal device.

[0168] For example, as shown in Figure 3, when a terminal device moves to any grid in the channel map, a second network device can trigger a channel map request message to request the first channel map of the first network device corresponding to the terminal device. The first channel map includes the first basis of the first network device corresponding to the terminal device. For example, the second network device can determine the first basis as the joint space-frequency basis based on the path angle-delay information in the channel map.

[0169] Optionally, if the core network device is an AMF, for example, the second network device sends a first request message to the AMF. The AMF acts as a router for communication between the second network device and the LMF / MMF. The second network device then requests the LMF / MMF to obtain the channel map via the AMF. Correspondingly, the LMF / MMF can send the channel map to the second network device via the AMF. Therefore, after obtaining the first channel map, the second network device can determine the first basis based on the first channel map.

[0170] S920. The first network device sends a first reference signal to the terminal device.

[0171] The first reference signal is used to measure interference channel information of the first network device, and may specifically be a downlink reference signal. The downlink reference signal may include a CSI-RS, a synchronization signal / physical broadcast channel block (SSB), or a demodulation reference signal (DMRS).

[0172] Optionally, the density of the first reference signal is positively correlated with the number of columns of the first basis. Specifically, the density ρ of the first reference signal is proportional to the number of columns L of the first basis. For example, the smaller L is, the smaller ρ is. It can be understood that the smaller the number of columns L of the first basis, the fewer the number of channel multipaths, and the fewer the values ​​that need to be measured for the channel, and correspondingly, the fewer the reference signals that need to be sent; therefore, the density ρ of the first reference signal is proportional to the number of columns L of the first basis. For example, assuming that the first basis is a space-frequency joint basis U, and the space-frequency joint basis corresponding to the known terminal device is Wherein, M is the number of antennas of the first network device, L is the number of channel multipaths, and N is the number of frequency units; the first network device sets the density ρ of the first reference signal on the column number L of the space-frequency joint basis U, which can reduce the frequency domain granularity from N to N1, thereby reducing the reference signal overhead.

[0173] S930: The terminal device determines a first superposition coefficient vector based on the first reference signal and the first basis.

[0174] Specifically, the terminal device determines the first superposition coefficient vector based on the first reference signal and the first basis, including:

[0175] First, the terminal device determines a second channel matrix based on a first reference signal; and determines a second superposition coefficient vector based on the second channel matrix and a second basis; and then determines a first superposition coefficient vector based on the second superposition coefficient vector.

[0176] In which, the second basis is constructed by indexing the position of the first reference signal in the space-frequency domain in the corresponding row of the first basis, the second channel matrix is ​​the channel state information of the first reference signal in the corresponding space-domain dimension, the dimension of the second channel matrix is ​​MN1×1, the dimension of the second basis is MN1×1, M is the number of antenna ports receiving the first reference signal, N is the number of frequency domain units carrying the first reference signal, wherein the first superposition coefficient vector includes K superposition coefficients, the second superposition coefficient vector includes L superposition coefficients, the K superposition coefficients are the K elements with the largest amplitude in the second superposition coefficient vector, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, K is a positive integer less than or equal to L, and L is less than or equal to MN1.

[0177] For example, assuming that the first reference signal is a CSI-RS signal, the terminal device performs channel estimation on the CSI-RS signal to obtain a second channel matrix h in the spatial dimension s The dimension of the second channel matrix is ​​MN1×1, for example, h s satisfy M is the spatial domain granularity of the first reference signal (such as the number of antennas), and N1 is the frequency domain granularity of the first reference signal (such as the number of subcarriers or the number of RBs or the number of RBGs or the number of subbands, etc.).

[0178] The second basis constructed by the position index of the first reference signal in the space-frequency domain in the corresponding row of the first basis is represented by U s The dimension of the second base is MN1×L, for example, U s satisfy For example, the terminal device receives the first reference signal and can determine the position index of the first reference signal in the space-frequency domain; based on the position index (M and N1) of the first reference signal in the space-frequency domain, obtain the row corresponding to the position index from the first basis to form the second basis U s .

[0179] The second superposition coefficient vector is determined based on the second basis constructed by the position index of the second channel matrix and the first reference signal in the space-frequency domain in the corresponding row of the first basis, and satisfies formula (17): c=pinv(U s )×h s (17)

[0180] Among them, c is the second superposition coefficient vector, h s is the second channel matrix, U s is the second basis, and pinv(A) represents the pseudo-inverse of matrix A. Optionally, formula (17) is only an example, and the second superposition coefficient vector can also satisfy the deformation based on formula (17), or satisfy the h s and U s The present application does not limit other methods of generating . The second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, and L is a positive integer; for example, c satisfies Optionally, the superposition coefficient vector represents the projection coefficients of the channel matrix on the basis.

[0181] After the second superposition coefficient vector is determined by the above method, the first superposition coefficient vector can be determined based on the second superposition coefficient vector.

[0182] Specifically, the first superposition coefficient vector includes K superposition coefficients, and the K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector. K is a positive integer less than or equal to L. For example, it is known that the second superposition coefficient vector includes L superposition coefficients. Assuming that the K elements with the largest amplitudes in the L superposition coefficients constitute the first superposition coefficient vector c′, then c′ satisfies K satisfies 0 <K≤L。

[0183] It should be understood that the K elements with the largest amplitudes among the L superposition coefficients satisfy the requirement that the K coefficients are greater than the LK superposition coefficients other than the K coefficients in the L superposition coefficients; for example, assuming that the L superposition coefficients are 1, 3, 4, 6, 2, 5, then L = 6; assuming that K = 3, the K elements with the largest amplitudes among all elements in the L superposition coefficients include 4, 5, and 6, that is, the second superposition coefficient vector includes three elements, namely 4, 5, and 6.

[0184] S940: The terminal device sends a first superposition coefficient vector and a first basis selection vector to the second network device.

[0185] The first superposition coefficient vector, the first basis selection vector and the first basis jointly represent a first channel matrix of the first network device.

[0186] The first basis selection vector includes the position indices of the K superposition coefficients in the second superposition coefficient vector, where the position indices correspond to the column indices of the first basis. For example, assuming the L superposition coefficients are 1, 3, 4, 6, 2, and 5, then L = 6; assuming K = 3, the first superposition coefficient vector includes three superposition coefficients: 4, 5, and 6. The position indices of these three superposition coefficients in the second superposition coefficient vector are 3, 6, and 4, respectively, meaning that the first basis selection vector includes three elements: 3, 4, and 6.

[0187] Optionally, the terminal device sends the first superposition coefficient vector and the first basis selection vector. For example, the terminal device may use PUCCH / PUSCH to send the first superposition coefficient vector and the first basis selection vector to the second network device. Optionally, the terminal device may report the first superposition coefficient vector in a short period. The terminal device may report the first basis selection vector in a short period or a long period, which is not limited in this application.

[0188] It can be seen that the terminal device only needs to feed back K superposition coefficients (similar to the short-period superposition coefficients shown in Figure 8) and the position index of the K superposition coefficients in the second superposition coefficient vector (indicating the position index on the first basis), which is beneficial to reducing the feedback overhead of the terminal device to the second network device.

[0189] S950: The second network device sends a first superposition coefficient vector and a first basis selection vector to the first network device.

[0190] S960: The first network device performs channel recovery according to the first superposition coefficient vector and the first basis selection vector.

[0191] First, the first network device obtains the first basis. For example, the first network device sends a channel map request message to the core network device. The channel map request message is used to request the first channel map of the first network device, thereby obtaining the first basis of the first network device corresponding to the terminal device.

[0192] The first network device performs channel recovery, including: the first network device determines a first channel matrix based on a first superposition coefficient vector, a first basis selection vector, and a first basis.

[0193] Specifically, the first channel matrix can be obtained by multiplying the first superposition coefficient vector and the third basis. The third basis is composed of the K position indices in the first basis selection vector in the corresponding columns of the first basis, satisfying formula (18): I =U I ×c′ (18)

[0194] Among them, h I is the first channel matrix, U I The third base.

[0195] Optionally, the method of the present application also includes the following steps S970 to S991.

[0196] S970. The first network device sends a second reference signal to the terminal device, and the second network device sends a third reference signal to the terminal device.

[0197] The time domain resources, frequency domain resources and pilot sequences of the second reference signal and the third reference signal are the same.

[0198] It should be understood that the second reference signal and the third reference signal are used to measure the channel matrix from the second network device to the terminal device, and can specifically be a downlink reference signal. The downlink reference signal can include a CSI-RS, a synchronization signal / physical broadcast channel block (SSB), or a demodulation reference signal (DMRS).

[0199] S980, the terminal device determines a third superposition coefficient vector based on the second reference signal, the third reference signal and the fourth basis, wherein the fourth basis is the channel basis of the second network device, and the fourth basis is composed of R columns of basis vectors, where R is a positive integer.

[0200] Before or during this step, the terminal device needs to obtain the fourth basis, for example, receive the fourth basis sent by the second network device. For details, please refer to the method in which the terminal device obtains the third basis in S910.

[0201] First, the terminal device determines a third channel matrix based on the second reference signal and the third reference signal, where the third channel matrix is ​​the sum of the fourth channel matrix of the first network device and the first channel matrix of the second network device; then, the fourth channel matrix of the second network device is determined based on the first channel matrix and the third channel matrix, where the fourth channel matrix represents the channel matrix from the second network device to the terminal device; then, a third superposition coefficient vector is determined based on the fourth channel matrix and the fourth basis, where the third superposition coefficient vector includes Q superposition coefficients, where Q is a positive integer less than or equal to R.

[0202] Among them, the first channel matrix, the third channel matrix and the fourth channel matrix satisfy formula (19): C =h U -h I

[0203] Among them, h C is the fourth channel matrix, h U is the third channel matrix.

[0204] S990: The terminal device sends the third superposition coefficient vector and the second basis selection vector to the second network device.

[0205] The third superposition coefficient vector, the second basis selection vector, and the fourth basis jointly represent a fourth channel matrix of the second network device.

[0206] The second basis selection vector includes the column index of the fourth basis corresponding to the Q superposition coefficients.

[0207] S991: The second network device performs channel recovery according to the third superposition coefficient vector, the second basis selection vector, and the fourth basis.

[0208] Specifically, the second network device determines the fourth channel matrix according to the third superposition coefficient vector, the second basis selection vector, and the fourth basis.

[0209] FIG10 shows another communication method 1000 provided in the present application. The method 1000 includes at least part of the method shown in FIG10 .

[0210] S1010, the terminal device obtains a first basis and a fourth basis, the first basis is a channel basis of the first network device (optionally, the first network device may be an interference station of the terminal device), and the fourth basis is a channel basis of the second network device (optionally, the first network device may be a service station of the terminal device), wherein the first basis is composed of L columns of basis vectors, L is a positive integer, and the fourth basis is composed of R columns of basis vectors, R is a positive integer.

[0211] Optionally, the method for the terminal device to obtain the first substrate and the fourth substrate refers to steps S910 and S980.

[0212] S1020. The first network device sends a first reference signal to the terminal device, and the second network device sends a fourth reference signal to the terminal device.

[0213] The first reference signal is used to measure interference channel information of the first network device, and the fourth reference signal is used to measure the channel matrix from the second network device to the terminal device. The first and fourth reference signals are orthogonal sparse reference signals. Orthogonal reference signals mean that the frequency domain resources of the first and fourth reference signals are staggered, or that the sequences of the first and fourth reference signals are orthogonal.

[0214] The first reference signal and the fourth reference signal may specifically be downlink reference signals, wherein the downlink reference signal may include a CSI-RS, a synchronization signal / physical broadcast channel block (SSB), or a demodulation reference signal (DMRS).

[0215] Optionally, the density of the first reference signal and the fourth reference signal is positively correlated with the number of columns of the first basis. Specifically, the density ρ of the first reference signal and the fourth reference signal is proportional to the number of columns L of the first basis. For example, the smaller L is, the smaller ρ is. It can be understood that the smaller the number of columns L of the first basis, the fewer the number of channel multipaths, and the fewer the values ​​that need to be measured for the channel, and correspondingly, the fewer the reference signals that need to be sent; therefore, the density ρ of the first reference signal is proportional to the number of columns L of the first basis. For example, assuming that the first basis is a space-frequency joint basis U, and the space-frequency joint basis corresponding to the known terminal device is Where M is the number of antennas of the first network device, L is the number of channel multipaths, and N is the number of frequency bins. The first network device sets the density ρ of the first reference signal based on the number of columns L of the joint space-frequency basis U. This can reduce the frequency domain granularity from N to N1, thereby reducing the reference signal overhead. Similarly, the second network device can set the density of the fourth reference signal based on the number of columns of the fourth basis.

[0216] S1030: The terminal device determines a first superposition coefficient vector based on the first reference signal and the first basis, and / or the terminal device determines a fourth superposition coefficient vector based on the fourth reference signal and the fourth basis.

[0217] Specifically, the terminal device determines the first superposition coefficient vector based on the first reference signal and the first basis in a manner similar to step S930.

[0218] The terminal device determines the fourth superposition coefficient vector based on the fourth reference signal and the fourth basis in step S930 (replace the first basis in step S930 with the fourth basis, and replace the first superposition coefficient vector with the fourth superposition coefficient vector).

[0219] S1040: The terminal device sends the first superposition coefficient vector and the first basis selection vector to the second network device, and / or the terminal device sends the fourth superposition coefficient vector and the basis selection vector corresponding to the fourth superposition coefficient vector to the second network device.

[0220] The first superposition coefficient vector, the first basis selection vector and the first basis together represent a first channel matrix of the first network device. The first channel matrix standardizes channel information of the first network device.

[0221] The fourth superposition coefficient vector, the basis selection vector corresponding to the fourth superposition coefficient vector, and the fourth basis jointly represent a fifth channel matrix of the second network device, and the fifth channel matrix represents channel information of the second network device.

[0222] It should be understood that the specific reporting method can refer to step S940.

[0223] S1050: The second network device sends a first superposition coefficient vector and a first basis selection vector to the first network device.

[0224] S1060: The first network device performs channel recovery according to the first superposition coefficient vector and the first basis selection vector.

[0225] First, the first network device obtains the first basis. For example, the first network device sends a channel map request message to the core network device. The channel map request message is used to request the first channel map of the first network device, thereby obtaining the first basis of the first network device corresponding to the terminal device.

[0226] The first network device performs channel recovery, including: the first network device determines a first channel matrix based on a first superposition coefficient vector, a first basis selection vector, and a first basis.

[0227] Specifically, the first channel matrix can be obtained by multiplying the first superposition coefficient vector and the third basis. The third basis is composed of the K position indices in the first basis selection vector in the corresponding columns of the first basis, satisfying formula (18): I =U I ×c′ I (18)

[0228] Among them, h I is the first channel matrix, U I The third base.

[0229] The communication method embodiment of the present application is described in detail above in conjunction with Figures 1 to 10. The communication device embodiment of the present application will be described in detail below in conjunction with Figures 11 and 12. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for portions not described in detail, reference can be made to the above method embodiment.

[0230] Figure 11 is a schematic diagram of a communication device provided in accordance with an embodiment of the present application. As shown in Figure 11, a communication device 1100 includes a processing module 1110 and a communication module 1120. The communication device 1100 may be a terminal device, or a communication device applied to a terminal device or used in conjunction with a terminal device and capable of implementing a method executed by the terminal device, such as a chip, a chip system, or a circuit; or the communication device 1100 may be a network device, or a communication device applied to a network device or used in conjunction with a network device and capable of implementing a method executed by the network device, such as a chip, a chip system, or a circuit;

[0231] The communication module may also be referred to as a transceiver module, transceiver, transceiver, or transceiver device. The processing module may also be referred to as a processor, processing board, processing unit, or processing device. Optionally, the communication module is used to perform the sending and receiving operations of the terminal device and network device in the above method. The device used to implement the receiving function in the communication module can be considered a receiving unit, and the device used to implement the sending function in the communication module can be considered a sending unit. That is, the communication module includes a receiving unit and a sending unit.

[0232] When the communication device 1100 is applied to a terminal device, the processing module 1110 may be used to implement the processing functions of the terminal device in the above embodiments, and the communication module 1120 may be used to implement the transceiver functions of the terminal device in the above embodiments.

[0233] When the communication device 1100 is applied to a network device, the processing module 1110 can be used to implement the processing function of the network device in the above embodiments, and the communication module 1120 can be used to implement the transceiver function of the terminal device in the above embodiments.

[0234] In addition, it should be noted that the aforementioned communication module and / or processing module can be implemented by a virtual module, for example, the processing module can be implemented by a software functional unit or a virtual device, and the communication module can be implemented by a software function or a virtual device. Alternatively, the processing module or the communication module can also be implemented by a physical device, for example, if the device is implemented using a chip / circuit (such as an integrated circuit or a logic circuit, etc.). The communication module can be an input and output circuit and / or a communication interface, performing input operations (corresponding to the aforementioned receiving operations) and output operations (corresponding to the aforementioned sending operations); the processing module is an integrated processor or microprocessor or circuit (such as an integrated circuit or a logic circuit, etc.).

[0235] The division of modules in this application is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the examples of this application may be integrated into a single processor, exist physically as separate modules, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in either hardware or software functional modules.

[0236] FIG12 is a schematic diagram of another communication device provided in an embodiment of the present application. As shown in FIG12 , the communication device 1200 may optionally be a chip or a chip system. Optionally, in the present application, the chip system may be composed of a chip or may include a chip and other discrete devices.

[0237] The communication device 1200 can be used to implement the functions of any device (e.g., terminal device, network device) in the communication system described in the above examples. The communication device 1200 may include at least one processor 1210. Optionally, the processor 1210 is coupled to a memory, and the memory may be located within the device, or the memory may be integrated with the processor, or the memory may be located outside the device. For example, the communication device 1200 may also include at least one memory 1220. The memory 1220 stores the necessary computer programs, computer programs or instructions and / or data for implementing any of the above examples; the processor 1210 may execute the computer program stored in the memory 1220 to complete the method in any of the above examples.

[0238] The communication device 1200 may also include a communication interface 1230, through which the communication device 1200 can exchange information with other devices. Exemplarily, the communication interface 1230 may be a transceiver, circuit, bus, module, pin, or other type of communication interface. When the communication device 1200 is a chip-type device or circuit, the communication interface 1230 in the device 1200 may also be an input / output circuit that can input information (or receive information) and output information (or send information). The processor 1210 is an integrated processor, microprocessor, integrated circuit, or logic circuit, etc., and the processor can determine output information based on input information.

[0239] Coupling in this application refers to an indirect coupling or communication connection between devices, units, or modules, which can be electrical, mechanical, or other forms, and is used for information exchange between devices, units, or modules. Processor 1210 may operate in conjunction with memory 1220 and communication interface 1230. This application does not limit the specific connection medium between the processor 1210, memory 1220, and communication interface 1230.

[0240] Optionally, as shown in FIG12 , the processor 1210, the memory 1220, and the communication interface 1230 are interconnected via a bus 1240. Optionally, the bus may include an address bus, a data bus, a control bus, or other types of buses. Furthermore, for ease of illustration, FIG12 shows one bus 1240, but this does not mean that there is only one bus or only one type of bus.

[0241] It should be understood that the processors mentioned in the embodiments of the present application may be the following devices or the circuit portions of the following devices used for processing functions: a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0242] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may 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 may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0243] 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.

[0244] It should also be noted that the memory described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

[0245] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the methods executed by terminal devices and network devices in the above-mentioned method embodiments are stored.

[0246] An embodiment of the present application also provides a computer program product, comprising instructions, which, when executed by a computer, implement the methods performed by the terminal device and the network device in the above-mentioned method embodiments.

[0247] An embodiment of the present application also provides a communication system, which includes the terminal device and network device in the above embodiments.

[0248] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above and will not be described again here.

[0249] To facilitate understanding of the above embodiments provided in this application, the following points are explained:

[0250] 1) In this application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0251] 2) In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. 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. In the text description of this application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b and c can mean: a, or b, or c, or a and b, or a and c, or b and c, or a, b and c. Where a, b and c can be single or multiple, respectively.

[0252] 3) The ordinal numbers "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, the first indication information and the second indication information can be the same information or different information, and such names do not indicate differences in the content, size, application scenario, sender / receiver, priority, or importance of the two messages. In addition, the numbering of the steps in the various embodiments introduced in this application is only for distinguishing different steps and is not used to limit the order of the steps.

[0253] 4) In this application, descriptions such as "when...", "in the case of...", and "if" all mean that the device will perform corresponding processing under certain objective circumstances. They do not limit the time, nor do they require the device to perform judgment actions when implementing them, nor do they mean that there are other limitations.

[0254] 5) In this application, "indicate" or "used to indicate" can include being used for direct indication and being used for indirect indication. When describing that a certain indication information is used to indicate A, it can include that the indication information directly indicates A or indirectly indicates A, and does not necessarily mean that the indication information carries A.

[0255] The indication methods involved in the embodiments of this application should be understood to encompass various methods that enable the party to be indicated to obtain information about the information to be indicated. The information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately. The transmission period and / or timing of these sub-information can be the same or different. This application does not limit the transmission method, for example.

[0256] In the embodiments of the present application, the "indication information" may be an explicit indication, i.e., a direct indication via signaling, or may be obtained based on parameters indicated by the signaling, in combination with other rules, other parameters, or by deduction. It may also be an implicit indication, i.e., based on a rule or relationship, or based on other parameters, or by deduction. This application does not impose specific limitations on this.

[0257] 6) The “protocol” referred to in this application may refer to a standard protocol in the field of communications, such as the fourth generation (4G) th generation, 4G) network, fifth generation (5 th generation, 5G) network protocol, NR protocol, 5.5G network protocol, sixth generation (6 th generation, 6G) network protocols and related protocols used in future communication systems, which are not limited in this application.

[0258] 7) In this application, "communication" may also be described as "data transmission", "information transmission", "data processing", etc. "Transmission" includes "sending" and "receiving".

[0259] 8) In this application, "sending information to XX (device)" can be understood as the destination of the information being the device. This can include sending information directly or indirectly to the device. "Receiving information from XX (device)" can be understood as the source of the information being the device, which can include receiving information directly or indirectly from the device. The information may undergo necessary processing between the source and destination, such as format changes, but the destination can still understand the valid information from the source.

[0260] 9) The terms "comprise," "include," and "have," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0261] In various embodiments of the present application, 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.

[0262] In this application, under the premise of no logical contradiction, the examples can reference each other, for example, the methods and / or terms between method embodiments can reference each other, for example, the functions and / or terms between device embodiments can reference each other, for example, the functions and / or terms between device examples and method examples can reference each other.

[0263] It should be understood that in some of the above embodiments, the devices in the existing network architecture are mainly used as examples for illustrative description, and the specific form of the devices is not limited in the embodiments of the present application. For example, devices that can achieve the same functions in the future are applicable to the embodiments of the present application.

[0264] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of 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 beyond the scope of this application.

[0265] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be described again here.

[0266] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, 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 is that 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.

[0267] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0268] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0269] 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. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0270] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that, including: obtaining a first basis, where the first basis is a channel basis of a first network device, and the first basis is composed of L column basis vectors, and L is a positive integer; receiving a first reference signal sent by the first network device; determining a first superposition coefficient vector based on the first reference signal and the first basis, where the first superposition coefficient vector includes K superposition coefficients, and K is a positive integer less than or equal to L; sending the first superposition coefficient vector and a first basis selection vector to a second network device, where the first superposition coefficient vector, the first basis selection vector, and the first basis jointly represent a first channel matrix of the first network device, and the first basis selection vector includes K column indexes, and the K column indexes are indexes of basis vectors corresponding to the K superposition coefficients in the first basis; 2. The method according to claim 1, wherein The determining the first superposition coefficient vector based on the first reference signal and the first basis includes: determining a second channel matrix based on the first reference signal; determining a second superposition coefficient vector based on the second channel matrix and a second basis, where the second basis is constructed by corresponding rows of the first basis according to position indexes of the first reference signal in the space-frequency domain, the dimension of the second channel matrix is MN1×1, the dimension of the second basis is MN1×1, M is the number of antenna ports receiving the first reference signal, N is the number of frequency domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1; determining the first superposition coefficient vector based on the second superposition coefficient vector, and the K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector; 3. The method according to claim 2, wherein The smaller the value of L is, the smaller the density of the first reference signal is.

4. The method according to claim 2 or 3, characterized in that, The method further includes: multiplying the first superposition coefficient vector by a third basis to obtain the first channel matrix, where the third basis is composed of corresponding columns of the first basis according to K position indexes in the first basis selection vector; 5. The method according to any one of claims 1 to 4, characterized in that The method further includes: receiving a second reference signal sent by the first network device and a third reference signal sent by the second network device, where the time domain resources, frequency domain resources, and pilot sequences of the second reference signal and the third reference signal are the same; determining a third channel matrix based on the second reference signal and the third reference signal, where the third channel matrix is the sum of a fourth channel matrix of the first network device and a first channel matrix of the second network device; determining a fourth channel matrix of the second network device based on the first channel matrix and the third channel matrix; 6. The method according to claim 5, wherein The method further includes: obtaining a fourth basis, where the fourth basis is a channel basis of the second network device, and the fourth basis is composed of R column basis vectors, and R is a positive integer; determining a third superposition coefficient vector based on the fourth channel matrix and the fourth basis, where the third superposition coefficient vector includes Q superposition coefficients, and Q is a positive integer less than or equal to R; Send the third superposition coefficient vector and the second basis selection vector to a second network device, where the third superposition coefficient vector, the second basis selection vector, and the fourth basis jointly represent a fourth channel matrix of the second network device, and where the second basis selection vector includes Q column indices, and the Q column indices are indices of basis vectors in the fourth basis corresponding to the Q superposition coefficients.

7. The method according to claim 6, characterized in that, The first basis, the second basis, the third basis, or the fourth basis is a same type of basis, and the same type of basis is: a joint space-frequency basis, or a space domain basis and a frequency domain basis; Wherein, the joint space-frequency basis is a matrix constructed by one or more joint space-frequency domain basis vectors, the space domain basis is a matrix constructed by one or more space domain basis vectors, and the frequency domain basis is a matrix constructed by one or more frequency domain basis vectors.

8. The method according to any one of claims 1 to 7, characterized in that, The basis vector is any one of a discrete Fourier transform (DFT) basis vector, a fast Fourier transform (FFT) basis vector, an oversampled DFT basis vector, an oversampled FFT basis vector, or a vector determined based on a preset rule.

9. A communication method, characterized in that, Includes: Send a first basis to a terminal device, where the first basis is a channel basis of a first network device, and the first basis is composed of L column basis vectors, and L is a positive integer; Receive a first superposition coefficient vector and a first basis selection vector, where the first superposition coefficient vector, the first basis selection vector, and the first basis jointly represent a first channel matrix of the first network device, and where the first superposition coefficient vector includes K superposition coefficients, the first basis selection vector includes K column indices, the K column indices are indices of basis vectors in the first basis corresponding to the K superposition coefficients, and K is a positive integer less than or equal to L; Send the first superposition coefficient vector and the first basis selection vector to the first network device.

10. The method according to claim 9, characterized in that, The K superposition coefficients are the K elements with the largest amplitudes in a second superposition coefficient vector, where the second superposition coefficient vector is determined based on a second channel matrix and a second basis, the second basis is constructed by corresponding rows of the first basis according to position indices of a first reference signal sent by the first network device in the joint space-frequency domain, and the second channel matrix is determined based on the first reference signal; wherein, the dimension of the second channel matrix is MN1×1, the dimension of the second basis is MN1×L, M is the number of antenna ports for sending the first reference signal, N1 is the number of frequency domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1.

11. The method according to claim 9 or 10, characterized in that, The method further includes: Receive the first basis from a core network device.

12. The method according to claim 11, wherein The receiving the first channel basis from the core network device includes: Receive a first channel map of the first network device from the core network device, where the first channel map includes the first basis.

13. The method according to claim 12, characterized in that, The method further includes: Send a channel map request message to a core network device, where the channel map request message is used to request to obtain the first channel map.

14. The method according to any one of claims 9 to 13, characterized in that, The method further includes: Send a fourth basis to a terminal device, where the fourth basis is a channel basis of a second network device, and the fourth basis is composed of R column basis vectors, and R is a positive integer; Send a third reference signal; Receive a third superposition coefficient vector and a second basis selection vector, where the third superposition coefficient vector, the second basis selection vector, and the fourth basis jointly represent a fourth channel matrix of the second network device, where the third superposition coefficient vector includes Q superposition coefficients, Q is a positive integer less than or equal to R, the second basis selection vector includes Q column indices, and the Q column indices are indices of basis vectors in the fourth basis corresponding to the Q superposition coefficients; Determine the fourth channel matrix based on the fourth basis, the third superposition coefficient vector, and the second basis selection vector.

15. The method according to claim 14, characterized in that, The determining the fourth channel matrix based on the fourth basis, the third superposition coefficient vector, and the second basis selection vector includes: Multiply the third superposition coefficient vector by a fifth basis to obtain the fourth channel matrix, where the fifth basis is composed of corresponding columns in the fourth basis at Q position indices in the second basis selection vector.

16. The method according to claim 15, wherein The first basis, the second basis, the third basis, the fourth basis, or the fifth basis is a same type of basis, and the same type of basis is: a space-frequency joint basis, or, a spatial domain basis and a frequency domain basis; Wherein, the space-frequency joint basis is a matrix constructed by one or more space-frequency domain basis vectors, the spatial domain basis is a matrix constructed by one or more spatial domain basis vectors, and the frequency domain basis is a matrix constructed by one or more frequency domain basis vectors.

17. The method according to any one of claims 9 to 16, characterized in that The basis vector is any one of a discrete Fourier transform (DFT) basis vector, a fast Fourier transform (FFT) basis vector, an oversampled DFT basis vector, an oversampled FFT basis vector, or a vector determined based on a preset rule.

18. A communication method, characterized in that, Includes: Obtain a first basis, where the first basis is a channel basis of a first network device, and the first basis is composed of L column basis vectors, and L is a positive integer; Send a first reference signal to a terminal device; Receive a first superposition coefficient vector and a first basis selection vector, where the first superposition coefficient vector, the first basis selection vector, and the first basis jointly represent a first channel matrix of the first network device, and the first channel matrix is determined based on the first reference signal, where the first superposition coefficient vector includes K superposition coefficients, the first basis selection vector includes K column indices, the K column indices are indices of basis vectors in the first basis corresponding to the K superposition coefficients, and K is a positive integer less than or equal to L; Determine the first channel matrix based on the first basis, the first superposition coefficient, and the first basis selection vector.

19. The method according to claim 18, wherein The K superposition coefficients are the K elements with the largest amplitudes in the second superposition coefficient vector. The second superposition coefficient vector is obtained based on the second basis constructed from the corresponding rows of the first basis at the position indices of the first reference signal sent by the first network device in the space-frequency domain. The second channel matrix is determined based on the first reference signal. Wherein, the dimension of the second channel matrix is MN1×1, the dimension of the second basis is MN1×L, M is the number of antenna ports for sending the first reference signal, N1 is the number of frequency-domain units carrying the first reference signal, the second superposition coefficient vector includes L superposition coefficients, the dimension of the second superposition coefficient vector is L×1, M and N1 are positive integers, and L is less than or equal to MN1.

20. The method according to claim 18 or 19, characterized in that, Determining the first channel matrix based on the first basis, the first superposition coefficients, and the first basis selection vector includes: Multiplying the first superposition coefficient vector by a third basis to obtain the first channel matrix. The third basis is composed of the corresponding columns of the first basis at K position indices in the first basis selection vector.

21. The method according to any one of claims 18 to 20, characterized in that, The smaller the value of L, the smaller the density of the first reference signal.

22. The method according to any one of claims 18 to 21, characterized in that, The method further includes: Sending a second reference signal to the terminal device, where the second reference signal is used to determine a fourth channel matrix of the second network device.

23. The method according to claim 20, wherein The first basis, the second basis, or the third basis is a same-type basis. The same-type basis is: a space-frequency joint basis, or a space-domain basis and a frequency-domain basis; Wherein, the space-frequency joint basis is a matrix constructed by one or more space-frequency domain basis vectors, the space-domain basis is a matrix constructed by one or more space-domain basis vectors, and the frequency-domain basis is a matrix constructed by one or more frequency-domain basis vectors.

24. The method according to any one of claims 18 to 23, characterized in that, The basis vector is any one of a discrete Fourier transform (DFT) basis vector, a fast Fourier transform (FFT) basis vector, an oversampled DFT basis vector, an oversampled FFT basis vector, or a vector determined based on a preset rule.

25. A communication device, characterized in that, Includes: A unit for implementing the method according to any one of claims 1 to 8; or, a unit for implementing the method according to any one of claims 9 to 17; or, a unit for implementing the method according to any one of claims 18 to 24.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instruction. When the computer program or instruction is run, It executes the method according to any one of claims 1 to 8, or It executes the method according to any one of claims 9 to 17, or It executes the method according to any one of claims 18 to 24.

27. A communication system, characterized in that, Includes a terminal device, a first network device, and a second network device. The terminal device is configured to execute the method according to any one of claims 1 to 8, the first network device is configured to execute the method according to any one of claims 18 to 24, and the second network device is configured to execute the method according to any one of claims 9 to 17.

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