Communication method for feeding back precoding matrix, and apparatus

Abstract

A communication method for feeding back a precoding matrix, and an apparatus, which are applied to the technical field of communications. The method comprises: a first apparatus sending a reference signal; the first apparatus receiving first information, wherein the first information is used for indicating at least one precoding matrix, the at least one precoding matrix is determined on the basis of the reference signal, the at least one precoding matrix comprises a precoding matrix of each of at least one sub-band, and the at least one sub-band is some of all the sub-bands occupied by the reference signal; and the first apparatus receiving second information, wherein the second information is used for indicating at least one stream combination, each of the at least one stream combination comprises at least one stream, and the at least one precoding matrix is used for performing interpolation by taking each of the at least one stream combination as a granularity, so as to obtain precoding matrices respectively corresponding to all the sub-bands. The method can improve the precision of a precoding matrix obtained by means of interpolation.

Description

A communication method and apparatus for feedback precoding matrices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510200513.5, filed on February 21, 2025, entitled "A Communication Method and Apparatus for Feedback Precoding Matrix", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication method and apparatus for feedback precoding matrices. Background Technology

[0004] Multiple-input multiple-output (MIMO) technology is a key technology in wireless communication, capable of meeting the demands of high-speed transmission. This technology can utilize spatial resources to enable signals to achieve array gain, multiplexing and diversity gain, and interference cancellation gain in space without increasing system bandwidth, thereby improving the capacity and spectral efficiency of the communication system.

[0005] In MIMO technology, the receiving device can feed back a precoding matrix determined by the receiving device to the transmitting device based on the received reference signal. How to reduce the overhead of feeding back the precoding matrix requires further discussion. Summary of the Invention

[0006] This application provides a communication method and apparatus for feedback precoding matrices, which reduces the overhead of feedback precoding matrices.

[0007] In a first aspect, embodiments of this application provide a communication method that can be applied to a first device. In some examples, the first device may be a terminal or a device applicable to a terminal. The device applicable to a terminal may be a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core), chip system, or processor), or may be a logical node, logical module, or software capable of implementing all or part of the terminal's functions. The device applicable to a terminal may exist independently; for example, it may be independently manufactured, sold, or used. In other examples, the first device may be an access network device or a device applicable to an access network device. The devices applicable to access network equipment can be modules, communication modules, circuits or chips responsible for communication functions (such as modem chips, or SoC chips or SIP chips containing modem cores), chip systems or processors, or logical nodes, logical modules or software that can implement all or part of the functions of access network equipment. These devices can exist independently; for example, they can be independently manufactured, sold or used.

[0008] The method may include: a first device transmitting a reference signal and receiving first information and second information. The first information may be used to indicate at least one precoding matrix, which may be determined based on the reference signal. The at least one precoding matrix may include the precoding matrix of each of at least one subband, where the at least one subband is a subset of all subbands occupied (or corresponding to, or used) by the reference signal. The second information may be used to indicate (or configure, or determine) at least one stream combination, where each stream combination may include at least one stream. The at least one precoding matrix may be used to interpolate at the granularity of each stream combination to obtain precoding matrices corresponding to each of the subbands. Accordingly, the first device may interpolate the at least one precoding matrix at the granularity of each stream combination to obtain precoding matrices corresponding to each of the subbands.

[0009] In some implementations, in Scenario 1 below, all subbands occupied by the reference signal can be replaced with all subbands in the uplink resources configured (or scheduled, or indicated, or allocated) by the second device for the first device. In other implementations, in Scenario 2 below, all subbands occupied by the reference signal can be replaced with all subbands in the downlink resources configured (or scheduled, or indicated, or allocated) by the first device for the second device.

[0010] Optionally, the second information can be used to indicate (or configure, or determine) at least one stream combination, which can be understood as at least one of the following: the second information can be used to indicate (or configure, or determine) at least one stream combination for interpolation; the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity; or, the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity for interpolating the at least one precoding matrix.

[0011] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. This can include: the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands; correspondingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands.

[0012] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. Alternatively, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to some or all of the subbands. Accordingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to some or all of the subbands.

[0013] Optionally, the number of flows included in different flow combinations in the at least one flow combination may be the same or different.

[0014] Using this method, the first device can receive first information, which can be used to indicate the precoding matrix of a portion of all subbands occupied (or corresponding to, or used) by the reference signal. Thus, the first device can interpolate the precoding matrix of that portion of the subbands to obtain the precoding matrices corresponding to each of the subbands. In this method, the second device does not need to feed back the precoding matrix corresponding to each of the subbands, thereby reducing the overhead of feeding back the precoding matrix.

[0015] When applied to massive MIMO (Multi-Match MIMO) technology, this method can significantly reduce the overhead of the feedback precoding matrix. For example, massive MIMO technology may have a large number of antennas, resulting in a large number of antenna ports. Since the number of rows in the precoding matrix equals the number of transmit antenna ports, the feedback overhead of the precoding matrix for each sub-band increases with the number of antenna ports. This method can feed back only the precoding matrix for a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix. Similarly, massive MIMO technology may have a large bandwidth, resulting in a large number of sub-bands. This method can also feed back only the precoding matrix for a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix.

[0016] Alternatively, since the second device may not feed back the precoding matrix for each subband, this method can improve the accuracy of the fed-back precoding matrix without changing the overhead of the fed-back precoding matrix, thereby improving the accuracy of the precoding matrix recovered by the first device.

[0017] Furthermore, in this method, the second information can be used to indicate at least one stream combination; the at least one precoding matrix can be used to interpolate at the granularity of each stream combination to obtain the precoding matrices corresponding to each of the at least one stream combination. In this way, the second information can indicate highly similar streams as a stream combination, thereby improving the accuracy of the interpolated precoding matrix and thus improving transmission performance.

[0018] Secondly, embodiments of this application provide a communication method that can be applied to a second device. In some examples, the second device may be an access network device or a device applicable to an access network device. The device applicable to an access network device may be a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core, chip system, or processor) that can be used in the access network device, or it may be a logical node, logical module, or software that can implement all or part of the functions of the access network device. The device applicable to the access network device can exist independently; for example, it can be independently manufactured, sold, or used. In other examples, the second device may be a terminal or a device applicable to a terminal. The device applicable to a terminal may be a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core, chip system, or processor) that can be used in the terminal, or it may be a logical node, logical module, or software that can implement all or part of the functions of the terminal. The device applicable to the terminal can exist independently; for example, it can be independently manufactured, sold, or used.

[0019] The method may include: a second device capable of receiving a reference signal and transmitting first information and second information. The first information may be used to indicate at least one precoding matrix, which may be determined based on the reference signal. The at least one precoding matrix may include the precoding matrix of each of at least one subband, where the at least one subband is a subset of all subbands occupied (or corresponding to, or used) by the reference signal. The second information may be used to indicate (or configure, or determine) at least one stream combination, each of the at least one stream combination including at least one stream. The at least one precoding matrix may be used to interpolate at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to each of the subbands.

[0020] In some implementations, in Scenario 1 below, all subbands occupied by the reference signal can be replaced with all subbands in the uplink resources configured (or scheduled, or indicated, or allocated) by the second device for the first device. In other implementations, in Scenario 2 below, all subbands occupied by the reference signal can be replaced with all subbands in the downlink resources configured (or scheduled, or indicated, or allocated) by the first device for the second device.

[0021] Optionally, the second information can be used to indicate (or configure, or determine) at least one stream combination, which can be understood as at least one of the following: the second information can be used to indicate (or configure, or determine) at least one stream combination for interpolation; the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity; or, the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity for interpolating the at least one precoding matrix.

[0022] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. This can include: the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands; correspondingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands.

[0023] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. Alternatively, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to some or all of the subbands. Accordingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to some or all of the subbands.

[0024] Optionally, the number of flows included in different flow combinations in the at least one flow combination may be the same or different.

[0025] Using this method, the second device can send first information, which can be used to indicate the precoding matrix of a portion of all subbands occupied (or corresponding to, or used) by the reference signal. Thus, the first device can interpolate the precoding matrix of that portion of the subbands to obtain the precoding matrices corresponding to each of all subbands. In this method, the second device does not need to feed back the precoding matrix corresponding to each of all subbands, thereby reducing the overhead of feeding back the precoding matrix.

[0026] When applied to massive MIMO (Multi-Match MIMO) technology, this method can significantly reduce the overhead of the feedback precoding matrix. For example, massive MIMO technology may have a large number of antennas, resulting in a large number of antenna ports. Since the number of rows in the precoding matrix equals the number of transmit antenna ports, the feedback overhead of the precoding matrix for each sub-band increases with the number of antenna ports. This method can feed back only the precoding matrix for a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix. Similarly, massive MIMO technology may have a large bandwidth, resulting in a large number of sub-bands. This method can also feed back only the precoding matrix for a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix.

[0027] Alternatively, since the second device may not feed back the precoding matrix for each subband, this method can improve the accuracy of the fed-back precoding matrix without changing the overhead of the fed-back precoding matrix, thereby improving the accuracy of the precoding matrix recovered by the first device.

[0028] Furthermore, in this method, the second information can be used to indicate at least one stream combination; the at least one precoding matrix can be used to interpolate at the granularity of each stream combination to obtain the precoding matrices corresponding to each of the at least one stream combination. In this way, the second information can indicate highly similar streams as a stream combination, thereby improving the accuracy of the interpolated precoding matrix and thus improving transmission performance.

[0029] Based on the first or second aspect, in one possible design, the second information can be used to indicate N, where N is the number of flows included in each of the at least one flow combination, and N is a positive integer. The m-th flow combination in the at least one flow combination includes the 1+(m-1)*N to N+(m-1)*N flows in the flow corresponding to the data transmission, where m is a positive integer.

[0030] Optionally, the second information can be used to indicate N, which can be understood as: the second information can be used to indicate a first stream combination granularity, which can be a stream combination granularity based on manifold interpolation. For example, the first stream combination granularity can be a stream combination granularity that interpolates a precoding matrix indicated by a precoding matrix indicator based on a manifold, or the first stream combination granularity can be a stream combination granularity of a precoding matrix indicator interpolation method based on a manifold, or the first stream combination granularity can be a stream combination granularity that interpolates at least one precoding matrix indicated by the first information based on a manifold. Exemplarily, the first stream combination granularity can be one of the following: stream-by-stream, stream combination, or all streams.

[0031] With this design, when the second information indicates N, the first device can accurately determine the at least one flow combination based on the value of N. Furthermore, in this design, the second information can indirectly indicate the at least one flow combination by indicating N, and the overhead required for the second information is relatively small, thereby reducing signaling overhead.

[0032] Based on the first or second aspect, in one possible design, the first stream combination is any one of the at least one stream combination, and the second information may include an index of each stream in the first stream combination. With this design, the second information can accurately indicate the first stream combination. Furthermore, in this design, the second information may include an index of each stream in the first stream combination, so that the streams in the first stream combination can be continuous or discontinuous, thereby expanding the scope of application.

[0033] Based on the first or second aspect, in one possible design, the at least one stream combination may include a second stream combination, where the first stream is any stream in the second stream combination. The at least one precoding matrix can be used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain precoding matrices corresponding to each of the at least one subband, which may include: a first precoding vector and a second precoding vector being used to interpolate to obtain a third precoding vector. Wherein, the first precoding vector may be the precoding vector corresponding to the first stream in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first subband in the at least one subband; the second precoding vector may be the precoding vector corresponding to the first stream in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second subband in the at least one subband; the third precoding vector may be the precoding vector corresponding to the first stream in the third precoding matrix, and the third precoding matrix may be the precoding matrix of the third subband, where the third subband may be any subband other than the at least one subband among all the subbands. Through this design, the first device can accurately determine the third precoding vector based on the first and second precoding vectors, thereby accurately determining the third precoding matrix. Furthermore, in this design, the first device can determine the precoding vector corresponding to each stream in the third precoding matrix stream-by-stream, resulting in lower computational complexity.

[0034] Based on the first or second aspect, in one possible design, the at least one stream combination may include a third stream combination, which may include multiple streams. The at least one precoding matrix can be used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain precoding matrices corresponding to each of the at least one subband. This may include: a first matrix and a second matrix being interpolated to obtain a third matrix. The first matrix may include precoding vectors corresponding to the multiple streams in the first precoding matrix, which is the precoding matrix of the first subband among the at least one subband; the second matrix may include precoding vectors corresponding to the multiple streams in the second precoding matrix, which is the precoding matrix of the second subband among the at least one subband; the third matrix may include precoding vectors corresponding to the multiple streams in the third precoding matrix, which may be the precoding matrix of the third subband, which may be a subband other than the at least one subband among all the subbands. Through this design, the first device can accurately determine the third matrix based on the first and second matrices, thereby accurately determining the third precoding matrix. In addition, in this design, the first device can interpolate by combining streams to obtain the third matrix, which reduces the amount of computation compared to interpolating for each stream.

[0035] Based on the first or second aspect, in one possible design, the method further includes: a second device transmitting third information; and correspondingly, a first device receiving the third information. The third information can be used to indicate one or more stream combinations, each of which may include one or more streams, and these one or more stream combinations may be combinations of streams corresponding to the at least one precoding matrix. With this design, the third information can accurately indicate one or more stream combinations corresponding to the at least one precoding matrix.

[0036] Based on the first or second aspect, in one possible design, the third information can be used to indicate O, where O can be the number of streams included in each of one or more stream combinations, and O is a positive integer. The q-th stream combination in the one or more stream combinations may include the 1+(q-1)*O to the O+(q-1)*O streams in the stream corresponding to the data transmission, where q is a positive integer.

[0037] Optionally, the third information can be used to indicate O, which can be understood as: the third information can be used to indicate the second stream combination granularity, which can be the stream combination granularity corresponding to the precoding matrix (or precoding matrix indicator). For example, the second stream combination granularity can be the stream combination granularity corresponding to the precoding matrix (or precoding matrix indicator) of a subband, or the second stream combination granularity can be the stream combination granularity corresponding to the at least one precoding matrix. Exemplarily, the second stream combination granularity can be one of the following: stream-by-stream, stream combination, or all streams.

[0038] With this design, when the third information indicates 0, the first device can accurately determine the one or more flow combinations based on the value of 0. Furthermore, in this design, the third information can indirectly indicate the one or more flow combinations through the indication of 0, and the overhead required for the third information is relatively small, thereby reducing signaling overhead.

[0039] Based on the first or second aspect, in one possible design, the fourth stream combination is any one of the one or more stream combinations, and the third information may include the index of each stream in the fourth stream combination. With this design, the third information can accurately indicate the one or more stream combinations corresponding to the at least one precoding matrix.

[0040] Based on the first or second aspect, in one possible design, the first stream combination is any one of the at least one stream combinations, and all streams of the first stream combination belong to one of the one or more stream combinations. With this design, all streams in each of the at least one stream combinations used for interpolation belong to one of the one or more stream combinations corresponding to the at least one precoding matrix; thus, the first device can accurately determine the precoding matrices corresponding to all subbands by applying the at least one precoding matrix with each stream combination as the granularity.

[0041] Based on the first or second aspect, in one possible design, the method further includes: a second device sending first indication information; and correspondingly, a first device receiving the first indication information. The first indication information can be used to instruct interpolation of the precoding matrix of a portion of the subbands among all subbands. With this design, the first device accurately determines, based on the first indication information, that interpolation of at least one precoding matrix needs to be performed. Furthermore, in this design, the first device can perform interpolation of the at least one precoding matrix based on the indication from the second device, thereby improving the effectiveness and flexibility of the second device's management of the first device.

[0042] Based on the first or second aspect, in one possible design, the method further includes: a second device sending second indication information; and correspondingly, a first device receiving the second indication information. The second indication information can be used to indicate at least one of the following: the at least one sub-band, or the number of sub-bands in the at least one sub-band. With this design, the first device can accurately determine the at least one sub-band and / or the number of sub-bands in the at least one sub-band based on the second indication information. Furthermore, in this design, the at least one sub-band and / or the number of sub-bands in the at least one sub-band can be indicated by the second device, thereby improving the effectiveness and flexibility of the second device's management of the first device.

[0043] Thirdly, this application provides a communication device. In some examples, the communication device can be a terminal, or a device applicable to a terminal (e.g., a module, communication module, circuit or chip responsible for communication functions (e.g., a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logic node, logic module, or software capable of implementing all or part of the terminal's functions. The device applicable to the terminal can exist independently; for example, it can be independently manufactured, sold, or used. The communication device has the functions to implement the first or second aspect described above. In other examples, the communication device can be an access network device, or a device applicable to an access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (e.g., a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or a logic node, logic module, or software capable of implementing all or part of the access network device's functions. The device applicable to the access network device can exist independently; for example, it can be independently manufactured, sold, or used. The communication device has the functions to implement the second aspect described above.

[0044] In one possible design, the communication device includes modules, units, or means corresponding to the operations involved in any of the first to second aspects described above. These modules, units, or means can be implemented in software, hardware, or a combination of both. For example, the communication device includes an interface unit and a processing unit. The interface unit can be used to transmit and receive signals to enable communication between the communication device and other devices; the processing unit can be used to perform some internal operations of the communication device. The functions performed by the processing unit and the interface unit can correspond to the operations involved in any of the first to second aspects described above.

[0045] In one possible design, the communication device includes a processor. The processor is capable of executing computer programs or instructions, for example, executing computer programs or instructions stored in memory. When the computer program or instructions are executed, the communication device performs the methods in any of the possible designs described in the first to second aspects above.

[0046] Optionally, the processor is coupled to the memory via an interface, which is either a memory built into the communication device or an external memory connected to the communication device.

[0047] In one possible design, the communication device includes a processor and an interface circuit, wherein the processor is used to communicate with other devices through the interface circuit and to perform the methods in any of the possible designs in any of the first to second aspects described above.

[0048] Fourthly, this application provides a communication system that may include a first device and a second device. The first device is capable of executing the communication method provided in the first aspect, and the second device is capable of executing the communication method provided in the second aspect.

[0049] In some possible designs, the first device is a terminal and the second device is an access network device.

[0050] In other possible designs, the first device is an access network device and the second device is a terminal.

[0051] Fifthly, this application provides a computer-readable storage medium storing a computer program or instructions, wherein when the computer program or instructions are executed, the method in any possible design of any of the first to second aspects described above is implemented.

[0052] Sixthly, this application provides a computer program product comprising computer program code, wherein when the computer program code is run, any possible design method of any of the first to second aspects described above is implemented.

[0053] In a seventh aspect, this application provides a chip that may include at least one processor for executing computer programs or instructions in memory to implement the methods in any possible design of any of the first to second aspects described above.

[0054] The technical effects that can be achieved by any of the third to seventh aspects mentioned above can be described with reference to the technical effects that can be achieved by any of the possible designs in the first to second aspects mentioned above. Where there is overlap, no further discussion will be given. Attached Figure Description

[0055] Figure 1 is an architecture diagram of a communication system provided in an embodiment of this application;

[0056] Figure 2 is a schematic diagram of a precoding matrix provided in an embodiment of this application;

[0057] Figure 3 is a flowchart of a communication method provided in an embodiment of this application;

[0058] Figures 4A and 4B are schematic diagrams of several interpolation methods provided in the embodiments of this application;

[0059] Figures 5 to 8 are structural diagrams of another communication device provided in the embodiments of this application. Detailed Implementation

[0060] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. The technical solutions in the embodiments of this application can be applied to various communication systems, such as wireless local area networks (WLANs), wireless fidelity (Wi-Fi or WiFi) systems, fourth-generation (4G) mobile communication systems (such as long-term evolution (LTE) systems), fifth-generation (5G) mobile communication systems (such as new radio (NR) systems), or future communication systems. The methods provided in the embodiments of this application can be applied to terrestrial network communication systems or non-terrestrial network (NTN) communication systems. NTN communication systems can be, for example, satellite communication systems, and may also include unmanned aerial vehicles (UAVs), high-altitude platform stations (HAPS), and other aerial access network equipment; this application does not limit these aspects.

[0061] This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that individual systems may include additional devices, components, modules, etc., and / or may not include all devices, components, modules, etc. discussed in conjunction with the accompanying drawings. Furthermore, combinations of these approaches are also possible.

[0062] Figure 1 illustrates a schematic diagram of a communication system provided in an embodiment of this application. As shown in Figure 1, the communication system 10 includes a radio access network (RAN) 100 and a core network (CN) 200. Optionally, the communication system 10 may also include the Internet 300.

[0063] RAN 100 includes at least one RAN node (110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal (120a-120j in Figure 1, collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay equipment and / or wireless backhaul equipment (not shown in Figure 1). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wired connected to core network 200. The core network equipment in core network 200 and RAN node 110 in RAN 100 can be different physical devices, or they can be the same physical device integrating core network logical functions and wireless access network logical functions.

[0064] RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G mobile communication systems, or future-oriented evolution systems. RAN 100 can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a WiFi system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0065] RAN node 110, sometimes referred to as RAN entity or access node, constitutes part of the communication system and assists terminals in achieving wireless access. Multiple RAN nodes 110 in communication system 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminals 120j accessing RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes both referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal functions.

[0066] RAN nodes can also be described in different ways, such as access network equipment. Unless otherwise specified in this application, access network equipment will be used as the term.

[0067] Access network equipment can be devices or modules located on the network side of the aforementioned communication system and possessing corresponding communication functions. Access network equipment typically contains communication modules, circuits, or chips that perform the corresponding communication functions. Access network equipment may also be configured with programs or instructions for performing the corresponding communication functions, as well as the corresponding programs or instructions themselves.

[0068] In one possible scenario, access network equipment can be a base station (BS), an evolved NodeB (eNodeB), a transmission point (TP), an access point (AP), a transmission reception point (TRP), a mobile switching center, a next-generation NodeB (gNB), a next-generation base station in a future communication system, or an access node in a WiFi system. Access network equipment can also be a macro base station (as shown in Figure 1, 110a), a micro base station or indoor station (as shown in Figure 1, 110b), a relay node or donor node, a radio controller in a CRAN scenario, a satellite, a drone, a balloon, or an aircraft. Optionally, access network equipment can also be a server, wearable device, vehicle, or in-vehicle equipment. For example, in vehicle-to-everything (V2X) technology, the access network equipment can be a roadside unit (RSU). All or part of the functions of the access network device in this application can also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (e.g., a cloud platform).

[0069] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, with each device performing a portion of the base station's functions. For example, the access network devices can be centralized units (CUs or control units), distributed units (DUs), CU-control plane (CP), CU-user plane (UP), or radio units (RUs), etc. CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0070] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called an open CU (O-CU), DU can also be called an open DU (O-DU), CU-CP can also be called an open CU-CP (O-CU-CP), CU-UP can also be called an open CU-UP (O-CU-UP), and RU can also be called an open RU (O-RU). Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0071] A terminal is a device or module that connects to the aforementioned communication system and possesses corresponding communication functions. A terminal can also be called a terminal device, user equipment (UE), mobile station, mobile terminal, wireless terminal device, subscriber unit, subscriber station, mobile station, remote station, user terminal, user agent, or user device, etc. A terminal typically contains communication modules, circuits, or chips that perform the corresponding communication functions. The terminal may also be configured with programs or instructions for performing these communication functions.

[0072] Terminals can be widely used in various scenarios, such as device-to-device (D2D), V2X communication, machine-type communications (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. Wearable devices, also known as wearable smart devices or smart wearable devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables. Terminals used in vehicles are called in-vehicle terminal devices, which include, for example, transportation vehicles with wireless communication capabilities, communication modules, or on-board units (OBUs).

[0073] For example, a terminal may include a mobile phone (or "cellular" phone), a computer with a mobile terminal device, or a portable, pocket-sized, handheld, or computer-embedded mobile device. For instance, a terminal may be a Personal Communication Service (PCS) phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), or other similar devices. A terminal may also include restricted devices, such as devices with limited power consumption, limited storage capacity, or limited computing power. For example, a terminal may be an information sensing device such as a barcode scanner, radio frequency identification (RFID), a sensor, a global positioning system (GPS), or a laser scanner. The embodiments of this application do not limit the device form of the terminal.

[0074] In this application, core network equipment refers to equipment in the core network that provides service support to terminals. For example, in the case where CN200 is the core network of a future communication system, a 5G core network, or an evolved 5G core network, some examples of core network equipment include: access and mobility management function (AMF) entities, session management function (SMF) entities, user plane function (UPF) entities, policy control function (PCF) entities, etc., which are not listed here. Among them, the AMF entity can be responsible for terminal access management and mobility management; the SMF entity can be responsible for session management, such as user session establishment; the UPF entity can be a user plane functional entity, mainly responsible for connecting to external networks. For example, in the case of CN200 as a 4G core network, some core network devices include: Mobile Management Entity (MME), Home Subscriber Server (HSS), Serving Gateway (S-GW), Policy and Charging Rules Function (PCRF), Public Data Network Gateway (PDN Gateway, P-GW), etc., which will not be listed here. It should be noted that in this application, entities can also be referred to as network elements or functional entities. For example, an AMF entity can also be called an AMF network element or AMF functional entity, and similarly, an SMF entity can also be called an SMF network element or SMF functional entity. The aforementioned core network devices can operate independently or be combined to implement certain control functions. For example, AMF, SMF, and PCF can be combined into a single core network device.

[0075] The communication systems and service scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0076] The relevant terms used in the embodiments of this application will be explained below. It should be noted that these explanations are for the purpose of making the embodiments of this application easier to understand, and should not be regarded as a limitation on the scope of protection claimed by this application.

[0077] 1. Reference signal (RS):

[0078] Reference signals, also known as pilot signals, are essential in communication systems for transmitting and receiving data, obtaining system synchronization and feedback channel information, and estimating the uplink or downlink channel. Channel estimation refers to the process of reconstructing or recovering the received signal to compensate for signal distortion caused by channel fading and noise fading. It uses known reference signals from both the transmitter and receiver to determine the time and frequency domain variations of the channel. These reference signals, also called reference signals, are distributed across one or more resource elements (REs) in the time-frequency two-dimensional space within orthogonal frequency division multiplexing (OFDM) symbols, and have known amplitude and phase.

[0079] At the physical layer, uplink communication can include the transmission of uplink physical channels and uplink signals. Uplink physical channels include the Physical Random Access Channel (PRACH), Physical Uplink Control Channel (PUCCH), and Physical Uplink Shared Channel (PUSCH), etc. Uplink signals include the Sounding Reference Signal (SRS), the PUCCH Demodulation Reference Signal (PUCCH-DMRS), the PUSCH Demodulation Reference Signal (PUSCH-DMRS), the Demodulation Reference Signal (DMRS), the Phase Tracking Reference Signal (PTRS), and the Positioning Reference Signal (SRS), etc. The Positioning Reference Signal, for example, is the SRS for Positioning or the Positioning SRS.

[0080] At the physical layer, downlink communication can include the transmission of downlink physical channels and downlink signals. Downlink physical channels include the physical broadcast channel (PBCH), physical downlink control channel (PDCCH), physical downlink shared channel (PDSCH), etc. Downlink signals include the primary synchronization signal (PSS) / secondary synchronization signal (SSS), physical downlink control demodulation reference signal (PDCCH-DMRS), physical downlink shared channel demodulation reference signal (PDSCH-DMRS), DMRS, PTRS, channel state information reference signal (CSI-RS), cell reference signal (CRS), tracking reference signal (TRS), positioning reference signal (Positioning RS), SSB, etc. The full name of SSB in Chinese and English can be Synchronization Signal Block or Synchronization Signal (SS) / PBCH Block.

[0081] It should be understood that the reference signals listed above are merely examples and should not be construed as limiting this application. This application does not preclude the possibility of defining other reference signals in future agreements to achieve the same or similar functions.

[0082] 2. Precoding and codebook:

[0083] In communication systems, the mathematical expression for communication is y = Hx + n, where y is the received signal, H is the MIMO channel, x is the transmitted signal, and n is noise. In communication systems with multiple antennas, signals from multiple transmitting antennas can be superimposed on any one receiving antenna. Therefore, the method of transmitting signals at the transmitting end affects the system performance, and recovering the transmitted signal at the receiving end is often complex. In this context, precoding can reduce system overhead and maximize the system capacity of MIMO, while also reducing the complexity of eliminating inter-channel interference at the receiver. In this case, the mathematical expression is y = HPx + n, where P is the precoding matrix (or vector, or precoder). To simplify implementation complexity, P can be selected from a predefined set of matrices (or vectors), called the codebook. This signal transmission method is also called a codebook-based transmission method. If the transmitting end has all the information of H, then P can be obtained at the transmitting end itself; this signal transmission method is called a non-codebook (NCB) transmission method.

[0084] 3. Precoding Matrix Indicator (PMI):

[0085] The Precoding Matrix (PMI) can be used to instruct the terminal to determine the precoding matrix for downlink transmission. This precoding matrix can be determined by the terminal based on received reference signals. Optionally, the precoding matrix can be determined by the terminal based on a channel matrix. This channel matrix can be determined by the terminal based on received reference signals (e.g., CSI-RS). Exemplarily, the channel matrix can be determined by the terminal through channel estimation or based on channel reciprocity. For example, the terminal can perform channel estimation based on the received reference signals to determine the channel matrix, and thus determine the precoding matrix.

[0086] It should be understood that the specific methods used by the terminal to determine the precoding matrix are not limited to those described above. Specific implementations can be found in the protocol; for brevity, they are not listed here. For example, the precoding matrix can be obtained by performing singular value decomposition (SVD) on the channel matrix or its covariance matrix, or by performing eigenvalue decomposition (EVD) on the covariance matrix of the channel matrix. It should be understood that the methods for determining the precoding matrix listed above are merely examples and should not constitute any limitation on this application.

[0087] PMI can include wideband PMI and / or subband PMI. Both wideband PMI and subband PMI are related to subband. For ease of understanding, subband will be explained first below.

[0088] In some possible approaches, subbands can be divided based on common resource blocks (CRBs), each CRB comprising a physical resource block (PRB). The size of the subband can be determined based on the size of the bandwidth part (BWP) and the configuration of the access network equipment. For example, Table 1 shows one possible correspondence between subband size and BWP size.

[0089] Table 1

[0090] Assuming the BWP size is 76 PRBs (meaning one BWP consists of 76 PRBs), and the subband size configured for the access network device is the first value in Table 1, then the subband size can be 8 PRBs. For example, CRB0 to CRB7 can be one subband, CRB8 to CRB15 can be another subband, and so on.

[0091] Optionally, the boundaries of the BWP and the subbands may not be aligned, thus the actual size of the subbands at the BWP boundaries will be smaller. For example, within a BWP, the CRBs corresponding to the CSI-RS resources are CRB2 to CRB77, and there are a total of 10 subbands within this BWP, namely subbands A to J. Subband A includes CRB2 to CRB7, and subband J includes subbands CRB72 to 77.

[0092] It should be understood that the above description of subbands is merely an example. In practical applications, subbands can be divided in other ways without limitation. For example, a subband can be understood as any of the following: one or more REs, one or more resource blocks (RBs), one or more precoding resource block groups (PRGs), or one or more physical resource block groups (PRGs).

[0093] The broadband in a broadband PMI can include all subbands configured (or scheduled, or indicated, or allocated) by the access network equipment for the terminal. A broadband PMI refers to a PMI reported by the terminal for that broadband. For example, if the subbands configured (or scheduled, or indicated, or allocated) by the access network equipment for the terminal include: subband B, subband C, subband D, subband E, subband G, and subband H, then the terminal can receive reference signals (e.g., CSI-RS) on these subbands, obtain a PMI (i.e., broadband PMI), and report the PMI to the access network equipment.

[0094] Optionally, after receiving the reference signal, the receiving device can determine the precoding matrix for each sub-band based on the reference signal and feed back the PMI corresponding to the precoding matrix of each sub-band to the transmitting device. In this way, the transmitting device can determine the precoding matrix used for transmitting signals based on the precoding matrix of each sub-band. In other words, the sub-band PMI can refer to the PMI reported by the terminal for each sub-band configured (or scheduled, or indicated, or allocated) by the access network device.

[0095] For example, the downlink resources configured (or scheduled, or indicated, or allocated) by the access network device for the terminal include R subbands, where R is a positive integer. The terminal processes the precoding matrix of each of the R subbands to obtain the PMI corresponding to the precoding matrix of each of the R subbands. The subband PMI sent by the terminal to the access network device may include: the PMI corresponding to the precoding matrix of each of the R subbands. For example, if the access network equipment configures (or schedules, or instructs, or allocates) subbands for the terminal, including subband B, subband C, subband D, subband E, subband G, and subband H, then the terminal determines subband PMI#1 based on the reference signal (e.g., CSI-RS) received on subband B, determines subband PMI#2 based on the reference signal (e.g., CSI-RS) received on subband C, and so on. The terminal determines a subband PMI based on the reference signal (e.g., CSI-RS) received on each of these subbands and reports the determined multiple subband PMIs to the access network equipment.

[0096] The precoding matrix for each of the R subbands is illustrated below with reference to Figure 2. As shown in Figure 2, the precoding matrix for the k-th subband of the R subbands can be represented as P. k (1) P k (1) The number of rows and columns are S (the number of antenna ports) and J (the number of streams), respectively. Here, k takes integer values ​​from 1 to R, and S and J are positive integers. P k (1) The s-th row vector in P is the precoding vector corresponding to the s-th antenna port; k (1)The j-th column vector in the vector is the precoding vector corresponding to the j-th stream, where s takes integers from 1 to S and j takes integers from 1 to J.

[0097] Optionally, the access network device can determine the precoding matrix based on the PMI from the terminal. For example, the access network device can determine the CSI-RS port, the discrete Fourier transform (DFT) vector, and the space-frequency vector combining coefficients used to construct the precoding vector based on the PMI from the terminal, and thus determine the precoding matrix. This precoding matrix can be directly used to transmit downlink signals (e.g., downlink data); or it can be processed through one or more beamforming methods, such as zero forcing (ZF), regularized zero-forcing (RZF), minimum mean-squared error (MMSE), and maximizing the signal-to-leakage-and-noise ratio (SLNR), to obtain the final precoding matrix used for transmitting downlink signals. This application does not limit this.

[0098] It is understandable that the precoding matrix determined by the terminal can be interpreted as the precoding matrix to be fed back. The terminal can indicate the precoding matrix to be fed back through the PMI, so that the access network device can recover the precoding matrix based on the PMI. Optionally, the precoding matrix recovered by the access network device based on the PMI can be the same as or similar to the precoding matrix to be fed back. The higher the similarity between the precoding matrix determined by the access network device based on the PMI and the precoding matrix determined by the terminal, the more well the precoding matrix determined by the access network device for transmitting downlink signals can be adapted to the channel state, and therefore the better the signal reception quality can be improved.

[0099] Optionally, PMI can be used for downlink MIMO.

[0100] 4. Send the transmitted precoding matrix indicator (TPMI):

[0101] TPMI can be used to instruct access network devices on the precoding matrix used for uplink transmission. For details on TPMI, please refer to the explanation of PMI above, except that the access network devices and terminals are interchanged, CSI-RS is replaced with SRS, and downlink is replaced with uplink; further details will not be repeated here.

[0102] 5. Antenna Port:

[0103] An antenna port, often simply called a port, is a logical concept. It can be understood as a virtual transmitting antenna (or antenna array) identified by the receiver, or a spatially distinguishable virtual transmitting antenna (or antenna array). An antenna port generally corresponds to a physical antenna. Each antenna port represents a channel model, which can be derived from a reference signal on the antenna port. Therefore, an antenna port is usually associated with a reference signal, and its meaning can be understood as a transmit / receive interface on the channel through which the reference signal passes. Because antenna ports can be associated with reference signals, each antenna port can be called a port for a reference signal, such as a CSI-RS port, DMRS port, or SRS port. For low frequencies, an antenna port may correspond to one or more antenna elements that jointly transmit the reference signal; the receiver can treat them as a whole without distinguishing between individual elements. For high-frequency systems, an antenna port may correspond to a beam; similarly, the receiver only needs to treat this beam as an interface without distinguishing between individual elements.

[0104] A set of multiple antenna ports can be called a port set. In one approach, multiple digital ports of an access network device are grouped to form multiple port sets. In another approach (e.g., in a hybrid beamforming (HBF) architecture), a port set can be multiple digital ports corresponding to the same analog beam, also simply called a port set, or a digital-to-analog port set. Alternatively, a port set can be a set of digital ports corresponding to multiple analog beams, also simply called a port set, or a digital-to-analog port set. Or, multiple digital ports corresponding to an analog beam can be divided into multiple subsets, each subset being called a port set, or a digital-to-analog port set.

[0105] In protocols, antenna ports are typically identified by "antenna port" or "port," but they can also be identified by resources (such as CSI-RS resources, SRS resources, DMRS resources, PTRS resources, CRS resources, TRS resources, or SSB resources) or resource groups. In other words, the identifier for an antenna port can be replaced with one of the above-mentioned identifiers; for example, an antenna port can be replaced with an identifier for a resource, a pilot resource, or a reference signal resource.

[0106] A port set may contain one or more antenna ports, typically corresponding to one or more resources. Therefore, a port set can also be replaced with other names, such as resource group, resource set, pilot resource group, pilot resource set, reference signal resource group, reference signal resource set, port group, antenna port group, antenna port set, or antenna port collection, etc., without limitation. In this embodiment, the port set can also be replaced with "port #A to port #B". Here, port #A and port #B can be understood as examples of port indices. The antenna ports indicated by ports #A to #B can be understood as antenna ports indexed from #A to #B, and these antenna port indices are consecutive. In this embodiment, the port set can also be replaced with the index of each antenna port included in the port set. In this case, the antenna ports included in the port set can be consecutive antenna ports or non-consecutive antenna ports.

[0107] 6. Flow:

[0108] In a spatial multiplexing MIMO system, multiple parallel data streams can be transmitted simultaneously on the same frequency domain resources, and each data stream is called a stream. Streams in MIMO may also have other names, such as layer, spatial layer, transport layer, data layer, or spatial stream, etc., as long as they have the same meaning, they are all within the protection scope of this application.

[0109] 7. In this application, "instruction" or "for instruction" may include explicit instruction (or direct instruction) and implicit instruction (or indirect instruction). When describing information for instructing A, it may include whether the information explicitly instructs A or implicitly instructs A, but does not necessarily mean that the information carries A.

[0110] The indication methods involved in the embodiments of this application should be understood to cover various methods that enable the party to be indicated to obtain 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. Moreover, the sending period and / or sending time of these sub-information can be the same or different, without limitation.

[0111] In the embodiments of this application, "information" can be an explicit indication, that is, a direct indication through signaling, or obtained by combining other rules or parameters with parameters indicated by signaling, or by deduction. It can also be an implicit indication, that is, obtained based on rules or relationships, or based on other parameters, or by deduction. No limitation is imposed.

[0112] 8. In this application, communication between different devices can refer to direct communication between different devices (i.e., without the need for relaying or forwarding by other devices), or communication between different devices through other devices (i.e., requiring relaying or forwarding by other devices), or communication between a functional unit within a device and other devices through another functional unit. For example, "sending information to…(terminal)" can be understood as the destination of the information being the terminal, and may include sending information directly or indirectly to the terminal. "Receiving information from…(terminal)" can be understood as the source of the information being the terminal, and may include receiving information directly or indirectly from the terminal. Information may undergo necessary processing between the source and destination ends, such as format changes, digital-to-analog conversion, amplification, filtering, etc., but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood in a similar way, and will not be elaborated further here.

[0113] 9. In this application, the words "exemplarily," "for example," "for instance," and "example" are used to indicate examples, illustrations, or explanations, and are not intended to limit the scope of protection of this application. It should be understood that the examples in this application may also be implemented in other ways. In this application, "of," "corresponding, relevant," and "corresponding" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent when the distinction is not emphasized.

[0114] 10. In this application, any two of the programs, instructions and code may be substituted for one another.

[0115] 11. In this application, "greater than or equal to" and "greater than" are interchangeable. For example, "A is greater than threshold 1" and "A is greater than or equal to threshold 1" are interchangeable. "Less than or equal to" and "less than" are interchangeable. For example, "A is less than threshold 1" and "A is less than or equal to threshold 1" are interchangeable.

[0116] 12. In this application, some characters are in regular font, such as 'k'; some characters are in italic font, such as 'k'. When the same character is used in different fonts, it has the same meaning.

[0117] 13. In this application, the parameters in the formula can also be represented by other letters, as long as they have the same meaning, they are all within the scope of protection of this application.

[0118] 14. In this application, "in the case of," "when," "if," and "if," "then" can have the same meaning and can be substituted for each other. Optionally, in this application, "in the case of," "when," "if," and "then" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a time, nor do they require a judgment action at the time of implementation, nor do they imply the existence of other limitations.

[0119] 15. In this application, a precoding vector can be understood as at least one of the following: a vector used for precoding, or a vector in a precoding matrix (e.g., a row vector and / or a column vector).

[0120] 16. In this application, the manifold interpolation method can be understood as at least one of the following: a manifold-based interpolation method, a stream-based interpolation method, or a method of interpolation based on the precoding matrix and / or precoding vector corresponding to the stream.

[0121] 17. In this application, the stream corresponding to data transmission can be understood as at least one of the following: a stream corresponding to (or used) transmission, or a stream used for data transmission. Optionally, the stream corresponding to data transmission can be a stream corresponding to uplink data transmission or a stream corresponding to downlink data transmission. For example, in scenario 1 below, the stream corresponding to data transmission can be a stream corresponding to uplink data transmission. As another example, in scenario 2 below, the stream corresponding to data transmission can be a stream corresponding to downlink data transmission. Wherein, the stream corresponding to uplink data transmission can be understood as at least one of the following: a stream corresponding to (or used) uplink transmission, or a stream used for uplink data transmission. The stream corresponding to downlink data transmission can be understood as at least one of the following: a stream corresponding to (or used) downlink transmission, or a stream used for downlink data transmission.

[0122] 18. In this application, the index may be replaced with a sequence number or a number, etc. For example, the index of a sub-band may be replaced with the sequence number or number of the sub-band.

[0123] 19. In this application, the sub-band occupied by the reference signal can replace the sub-band corresponding to or used by the reference signal. For example, all sub-bands occupied by the reference signal can replace all sub-bands corresponding to or used by the reference signal.

[0124] Currently, after receiving a reference signal, the receiving device can determine the precoding matrix for each sub-band based on the reference signal and send a precoding matrix indication corresponding to the precoding matrix of each sub-band back to the transmitting device. In this way, the transmitting device can determine the precoding matrix used for transmitting the signal based on the precoding matrix of each sub-band. However, this method requires the receiving device to send the precoding matrix indication corresponding to the precoding matrix of each sub-band, resulting in significant overhead.

[0125] How to reduce the overhead of the feedback precoding matrix needs further discussion.

[0126] Based on this, embodiments of this application provide a communication method and apparatus for reducing the feedback overhead of precoding matrices. The method and apparatus described in this application are based on the same technical concept. Since the principles by which the method and apparatus solve the problem are similar, the implementations of the apparatus and method can be mutually referred to, and repeated details will not be elaborated further.

[0127] The communication method provided in the embodiments of this application will now be described in detail with reference to the accompanying drawings. This method can be applied to the communication system shown in FIG1, but is not limited thereto. The embodiments of this application will be described using the interaction between a first device and a second device as an example.

[0128] Optionally, this application can be used in scenario 1 and / or scenario 2.

[0129] Scenario 1: The first device can be a terminal or a device applicable to a terminal; the second device can be an access network device or a device applicable to an access network device. The device applicable to the terminal can be, for example, a module, a communication module, a circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), a chip system, or a processor; or a logical node, logical module, or software capable of implementing all or part of the terminal's functions. The device applicable to the access network device can exist independently; for example, it can be independently manufactured, sold, or used. The device applicable to the access network device can exist independently; for example, it can be independently manufactured, sold, or used.

[0130] Optionally, scenario 1 can be used for uplink MIMO.

[0131] Scenario 2: The first device may be an access network device or a device applicable to an access network device; the second device may be a terminal or a device applicable to a terminal. The devices applicable to terminals and devices applicable to access network devices are described in Scenario 1 and will not be repeated here.

[0132] Optionally, scenario 2 can be used for downlink MIMO.

[0133] It is understood that in the embodiments of this application, the first device and / or the second device may perform some or all of the steps in the embodiments of this application. These steps or operations are merely examples, and the embodiments of this application may also perform other operations or variations thereof. Furthermore, the steps may be performed in different orders as presented in the embodiments of this application, and it is not necessary to perform all the operations in the embodiments of this application.

[0134] Figure 3 is a flowchart illustrating a communication method provided in an embodiment of this application. As shown in Figure 3, the method may include:

[0135] S301: The first device sends a reference signal; correspondingly, the second device receives the reference signal.

[0136] The number of reference signals can be one or more.

[0137] Optionally, the reference signal may be a conventional reference signal. For example, in scenario 1 above, the reference signal may be SRS, and / or in scenario 2 above, the reference signal may be CSI-RS. In the subsequent standard evolution process, the name of the conventional reference signal may change or remain the same, all of which are within the protection scope of this application. Alternatively, the reference signal may be an evolution of the conventional reference signal. The name of the evolved reference signal may change or remain the same, all of which are within the protection scope of this application. Or, the reference signal may be a new reference signal or a reference signal defined in the future.

[0138] This application does not restrict the manner in which the first device transmits the reference signal; for example, it may transmit the signal in a manner specified in the protocol. This application also does not restrict the manner in which the second device receives the reference signal; for example, it may receive the signal in a manner specified in the protocol.

[0139] S302: The second device sends the first information; correspondingly, the first device receives the first information.

[0140] The first information can be used to indicate at least one precoding matrix. This application does not limit the manner in which the first information indicates the at least one precoding matrix; for example, it can be indicated in a manner specified by a protocol. The at least one precoding matrix can be determined based on a reference signal. Correspondingly, the second device can determine the at least one precoding matrix based on the reference signal. This application does not limit the manner in which the second device can determine the at least one precoding matrix based on the reference signal; for example, it can be determined in a manner specified by a protocol.

[0141] The at least one precoding matrix may include the precoding matrix of each of the at least one subband, and the at least one subband may be a portion of all subbands occupied by the reference signal. Optionally, the at least one subband may be continuous or discontinuous in the frequency domain.

[0142] For example, the reference signal occupies subbands #1 to #6; the at least one subband may include subband #1, subband #3 and subband #5, and correspondingly, the first information may indicate: the precoding matrix of subband #1, the precoding matrix of subband #3 and the precoding matrix of subband #5.

[0143] Optionally, the at least one subband can be understood as a subband in the first subband set; or, the at least one subband can be replaced by the first subband set. The first subband set may include a portion of the subbands occupied by the reference signal. For example, the reference signal occupies subbands #1 to #6; the first subband set may include subband #1, subband #3, and subband #5, and correspondingly, the first information may indicate: the precoding matrix of subband #1, the precoding matrix of subband #3, and the precoding matrix of subband #5.

[0144] In some implementations, in scenario 1 above, all subbands occupied by the reference signal can be replaced with all subbands in the uplink resources configured (or scheduled, or indicated, or allocated) by the second device for the first device. For example, the uplink resources configured (or scheduled, or indicated, or allocated) by the second device for the first device include subbands #1 to #6; the at least one subband may include subband #1, subband #3, and subband #5, and correspondingly, the first information may indicate the precoding matrix of subband #1, the precoding matrix of subband #3, and the precoding matrix of subband #5.

[0145] In other implementations, in scenario 2 above, all subbands occupied by the reference signal can be replaced with all subbands in the downlink resources configured (or scheduled, or indicated, or allocated) by the first device for the second device. For example, the uplink resources configured (or scheduled, or indicated, or allocated) by the first device for the second device include subbands #1 to #6; the at least one subband may include subband #1, subband #3, and subband #5, and correspondingly, the first information may indicate the precoding matrix of subband #1, the precoding matrix of subband #3, and the precoding matrix of subband #5.

[0146] Optionally, the at least one precoding matrix may correspond to the at least one subband; for example, the at least one precoding matrix may correspond one-to-one with the at least one subband.

[0147] Optionally, the at least one precoding matrix may be at least two precoding matrices, and the at least one subband may be at least two subbands.

[0148] In S302, the first information can be carried in a traditional message or in a new message. For example, in scenario 1 above, the first information can be carried in downlink control information (DCI), medium access control (or media access control, MAC) control element (MAC CE), or radio resource control (RRC) messages. As another example, in scenario 2 above, the first information can be carried in uplink control information (UCI), MAC CE, or RRC messages.

[0149] Optionally, the first information may have other names. For example, in scenario 1 above, the first information may be TPMI. And, for example, in scenario 2 above, the first information may be PMI.

[0150] S303: The second device sends the second information; correspondingly, the first device receives the second information.

[0151] The second information can be used to indicate (or configure, or determine) at least one stream combination, each of which may include at least one stream; correspondingly, the first device can determine the at least one stream combination based on the second information. The at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to each of the subbands; correspondingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to each of the subbands.

[0152] Optionally, the second information can be used to indicate (or configure, or determine) at least one stream combination, which can be understood as at least one of the following: the second information can be used to indicate (or configure, or determine) at least one stream combination for interpolation; the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity; or, the second information can be used to indicate (or configure, or determine) at least one stream combination as the interpolation granularity for interpolating the at least one precoding matrix.

[0153] The following section will first explain the at least one stream combination.

[0154] Optionally, the number of flows included in different flow combinations in the at least one flow combination may be the same or different. For example, the at least one flow combination includes flow combination #a1 to flow combination #a2. Flow combination #a1 includes flows #1 to #4; flow combination #a2 includes flows #5 to #8. As another example, the at least one flow combination includes flow combination #a1 to flow combination #a2. Flow combination #a1 includes flows #1 to #2; flow combination #a2 includes flows #3 to #8.

[0155] Optionally, the first flow combination is any one of the at least one flow combinations. When the first flow combination includes multiple flows, the indices of the multiple flows may be continuous or discontinuous; in other words, when the first flow combination includes multiple flows, the multiple flows may be continuous or discontinuous; or, the indices of the flows in each flow combination of the at least one flow combination may be continuous or discontinuous. For example, the at least one flow combination includes flow combination #a1 to flow combination #a2. Flow combination #a1 includes flows #1 to #4; flow combination #a2 includes flows #5 to #8. Also, for example, the at least one flow combination includes flow combination #a1 to flow combination #a2. Flow combination #a1 includes flows #1, #3, #5, and #7; flow combination #a2 includes flows #2, #4, #6, and #8.

[0156] In some implementations, the at least one stream combination may be determined based on the similarity between different streams; correspondingly, the second device may determine the at least one stream combination based on the similarity between different streams. For example, the at least one stream combination may have a high similarity between different streams within each stream combination. Optionally, the at least one stream combination may be determined based on the similarity between different streams, which can be understood as at least one of the following: the at least one stream combination may be determined based on the similarity between different precoding vectors corresponding to different streams, and correspondingly, the second device may determine the at least one stream combination based on the similarity between different precoding vectors corresponding to different streams; or, the at least one stream combination may be determined based on the similarity between different channels corresponding to different streams, and correspondingly, the second device may determine the at least one stream combination based on the similarity between different channels corresponding to different streams.

[0157] Optionally, the similarity between different streams can be determined based on the cosine similarity and / or normalized mean squared error (NMSE) between different channels corresponding to different streams; correspondingly, the combination of at least one stream can be determined based on the similarity between different streams, but this can be replaced by: the combination of at least one stream can be determined based on the cosine similarity and / or NMSE between different channels corresponding to different streams. Optionally, the cosine similarity and / or NMSE between different channels corresponding to different streams can be replaced by: the cosine similarity and / or NMSE between different precoding vectors corresponding to different streams.

[0158] In some examples, if the cosine similarity between different channels corresponding to different flows is greater than or equal to a first threshold, then the different flows may belong to one of the at least one flow combination. For example, the flows corresponding to data transmission include flows #1 to #8. If the cosine similarity between different channels corresponding to any two flows from flows #1 to #4 is greater than or equal to the first threshold, then flows #1 to #4 may belong to flow combination #a1 in at least one flow combination; if the cosine similarity between different channels corresponding to any two flows from flows #5 to #8 is greater than or equal to the first threshold, then flows #5 to #8 may belong to flow combination #a2 in at least one flow combination.

[0159] In other examples, if the NMSE between different channels corresponding to different flows is less than or equal to a second threshold, then the different flows may belong to one of the flow combinations in the at least one flow combination. For example, the flows corresponding to data transmission include flows #1 to #8. If the NMSE between different channels corresponding to any two flows in flows #1 to #4 is less than or equal to the second threshold, then flows #1 to #4 may belong to flow combination #a1 in at least one flow combination; if the NMSE between different channels corresponding to any two flows in flows #5 to #8 is less than or equal to the second threshold, then flows #5 to #8 may belong to flow combination #a2 in at least one flow combination.

[0160] In some other examples, if the cosine similarity between different channels corresponding to different flows is greater than or equal to a first threshold, and the NMSE between different channels corresponding to the different flows is less than or equal to a second threshold, then the different flows may belong to one of the at least one flow combination. For example, the flows corresponding to data transmission include flows #1 to #8. If the cosine similarity between different channels corresponding to every two flows from flows #1 to #4 is greater than or equal to the first threshold, and the NMSE between different channels corresponding to every two flows from flows #1 to #4 is less than or equal to the second threshold, then flows #1 to #4 may belong to flow combination #a1 in at least one flow combination; if the cosine similarity between different channels corresponding to every two flows from flows #5 to #8 is greater than or equal to the first threshold, and the NMSE between different channels corresponding to every two flows from flows #5 to #8 is less than or equal to the second threshold, then flows #5 to #8 may belong to flow combination #a2 in at least one flow combination.

[0161] The first threshold and / or the second threshold may be preset, such as as specified in the protocol; or may be notified to the first device by other devices (e.g., core network equipment or a second device); or may be determined by the first device.

[0162] As previously stated, the second information can be used to indicate the at least one combination of flows, and the indication can be in various ways, such as mode a1 and / or mode a2.

[0163] Method a1: The second information can be used to indicate N, where N is the number of streams included in each of the at least one stream combination, and N is a positive integer. The m-th stream combination in the at least one stream combination includes the 1+(m-1)*N to N+(m-1)*N streams in the stream corresponding to (or used for) data transmission, where m is a positive integer. m can take any integer from 1 to M, where M is the number of stream combinations in the at least one stream combination.

[0164] Optionally, in mode a1, the number of flows included in different flow combinations in the at least one flow combination is the same, that is, the number of flows included in each flow combination in the at least one flow combination is N.

[0165] Optionally, the second information can be used to indicate N, which can be understood as: the second information can be used to indicate a first stream combination granularity, which can be a stream combination granularity based on manifold interpolation. For example, the first stream combination granularity can be a stream combination granularity that interpolates a precoding matrix indicated by a precoding matrix indication (e.g., PMI or TPMI) based on a manifold, or the first stream combination granularity can be a stream combination granularity that interpolates at least one precoding matrix indicated by the first information based on a manifold. Exemplarily, the first stream combination granularity can be one of the following: stream-by-stream, stream combination, or all streams. When the granularity of the first stream combination is per-stream, each stream combination in the at least one stream combination includes one stream; when the granularity of the first stream combination is a stream combination, each stream combination in the at least one stream combination includes multiple streams; when the granularity of the first stream combination is all streams, the at least one stream combination may be a single stream combination that includes all streams, wherein the all streams are, for example, all streams corresponding to (or used) data transmission (e.g., uplink data transmission). It should be understood that the granularity of the first stream combination being all streams can be an example of the granularity of the first stream combination being a stream combination.

[0166] In some implementations, there is a correspondence between the value of the second information and the value of N (hereinafter referred to as the first correspondence); the first device can determine the value of N based on the value of the second information and the first correspondence, thereby determining the at least one stream combination. For example, all streams corresponding to (or used) the data transmission include streams #1 to #8, and the first correspondence is shown in Table 2A; the first device can determine the value of N and the at least one stream combination based on the value of the second information.

[0167] Table 2A

[0168] It should be understood that Table 2A is merely an example and is not intended to limit the scope of protection of this application. In practical applications, Table 2A may also have other variations. For example, it may include more or fewer rows and / or columns. Table 2A may also be transformed into Table 2B.

[0169] Table 2B

[0170] It should be understood that Table 2B is merely an example and is not intended to limit the scope of protection of this application. In practical applications, Table 2B may also have other variations, such as including more or fewer rows and / or columns.

[0171] Optionally, the first correspondence may be pre-set, such as as specified in an agreement; or it may be notified to the first device by other devices (e.g., core network equipment or a second device); or it may be determined by the first device.

[0172] In this method a1, when the second information indicates N, the first device can accurately determine the at least one flow combination based on the value of N. Furthermore, in this method, the second information can indirectly indicate the at least one flow combination by indicating N, and the overhead required for the second information is relatively small, thereby reducing signaling overhead.

[0173] Method a2: The first stream combination is any one of the at least one stream combination, and the second information may include the index of each stream in the first stream combination.

[0174] Optionally, method a2 can be understood as follows: for each of the at least one stream combination, the second information may include the index of each stream in the stream combination.

[0175] For example, the at least one stream combination includes stream combination #a1 and stream combination #a2. For stream combination #a1, if the second information includes indices of streams #1, #3, #5, and #7, then stream combination #a1 includes streams #1, #3, #5, and #7. For stream combination #a2, if the second information includes indices of streams #2, #4, #6, and #8, then stream combination #a2 includes streams #2, #4, #6, and #8.

[0176] Through this method a2, the second information can accurately indicate the first stream combination. Furthermore, in this method, the second information can include the index of each stream in the first stream combination, so that the streams in the first stream combination can be continuous or discontinuous, thereby expanding the scope of application.

[0177] The following explains that "the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands".

[0178] The specific contents of all sub-bands can be found in the description of all sub-bands in S302, and will not be repeated here.

[0179] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. This can include: the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands; correspondingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain the precoding matrices of all subbands except the at least one subband, thereby obtaining the precoding matrices corresponding to each of the subbands.

[0180] Exemplarily (hereinafter referred to as Example 1), all subbands include subbands #1 to #6; the first information may indicate: the precoding matrix of subband #1, the precoding matrix of subband #3, and the precoding matrix of subband #5. The at least one stream combination may include stream combination #a1 and stream combination #a2. The precoding matrices of subband #1, subband #3, and subband #5 can be interpolated at the granularity of stream combination #a1 and stream combination #a2 respectively to obtain the precoding matrices of subband #2, subband #4, and subband #6, thus obtaining the precoding matrices corresponding to all subbands. Correspondingly, the first device can interpolate the precoding matrices of subband #1, subband #3, and subband #5 at the granularity of stream combination #a1 and stream combination #a2 respectively to obtain the precoding matrices of subband #2, subband #4, and subband #6, thus obtaining the precoding matrices corresponding to all subbands.

[0181] Optionally, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to each of the subbands. This can be replaced by: the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to some or all of the subbands. Accordingly, the first device can interpolate the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to some or all of the subbands. The following description uses "the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain precoding matrices corresponding to each of the subbands" as an example.

[0182] The following is an exemplary description of how "the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands".

[0183] In some possible approaches, the first and second precoding matrices in the at least one precoding matrix can be used for interpolation at the granularity of each of the at least one stream combination to obtain a third precoding matrix; correspondingly, the first device can interpolate the first and second precoding matrices in the at least one precoding matrix at the granularity of each of the at least one stream combination to obtain a third precoding matrix. Wherein, the first precoding matrix is ​​the precoding matrix of the first subband in the at least one subband, the second precoding matrix is ​​the precoding matrix of the second subband in the at least one subband, and the third precoding matrix is ​​the precoding matrix of the third subband, where the third subband is any subband other than the at least one subband.

[0184] Optionally, the first and second precoding matrices in the at least one precoding matrix can be interpolated at the granularity of each of the at least one stream combination to obtain a third precoding matrix. This can be understood as follows: the third precoding matrix is ​​obtained by interpolating the first and second precoding matrices in the at least one precoding matrix at the granularity of each of the at least one stream combination.

[0185] It should be understood that this method is illustrated by taking "the first precoding matrix and the second precoding matrix as an example to interpolate at the granularity of each of the at least one stream combination to obtain the third precoding matrix". The precoding matrix of any subband except at least one subband can be obtained by interpolating the two precoding matrices in the at least one precoding matrix at the granularity of each of the at least one stream combination, thereby obtaining the precoding matrices corresponding to each of the subbands.

[0186] The following example illustrates how the first and second precoding matrices can be used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain the third precoding matrix, based on the relationship between the first, second, and third subbands.

[0187] In some implementations, the third sub-band may lie between the first and second sub-bands in the frequency domain. Optionally, if the indices of the sub-bands in the at least one sub-band are arranged in descending order of their corresponding frequencies, or if the indices of the sub-bands in the at least one sub-band are arranged in ascending order of their corresponding frequencies, then "the third sub-band may lie between the first and second sub-bands in the frequency domain" can be replaced with: the index of the third sub-band lies between the indices of the first and second sub-bands. Optionally, the first and second sub-bands may be the two sub-bands that are closest to the third sub-band in the frequency domain among the at least one sub-bands. In the example below, assume that all sub-bands include sub-bands #1 to #6, whose corresponding frequencies in ascending order are sub-band #1, sub-band #2, sub-band #3, sub-band #4, sub-band #5, and sub-band #6.

[0188] For example, in Example 1, the first subband can be subband #1, and the first precoding matrix is ​​the precoding matrix of subband #1; the second subband can be subband #3, and the second precoding matrix is ​​the precoding matrix of subband #3; the third subband is subband #2, and the third precoding matrix is ​​the precoding matrix of subband #2. Subband #2 is located between subband #1 and subband #3 in the frequency domain. The precoding matrices of subband #1 and subband #3 can be interpolated at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #2; correspondingly, the first device can interpolate the precoding matrices of subband #1 and subband #3 at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #2.

[0189] For example, in Example 1, the first subband can be subband #3, and the first precoding matrix is ​​the precoding matrix of subband #3; the second subband can be subband #5, and the second precoding matrix is ​​the precoding matrix of subband #5; the third subband is subband #4, and the third precoding matrix is ​​the precoding matrix of subband #4. Subband #4 is located between subband #3 and subband #5 in the frequency domain. The precoding matrices of subband #3 and subband #5 can be interpolated at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #4; correspondingly, the first device can interpolate the precoding matrices of subband #3 and subband #5 at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #4.

[0190] This implementation allows the precoding matrix of the third sub-band to be obtained by interpolating the precoding matrices of the two sub-bands located on either side of the third sub-band in the frequency domain, thereby improving the accuracy and precision of the determined precoding matrix of the third sub-band.

[0191] In other implementations, the third sub-band may be located on the same side of the first and second sub-bands in the frequency domain. Optionally, if the indices of the sub-bands in the at least one sub-band are arranged in descending order of their corresponding frequencies, or if the indices of the sub-bands in the at least one sub-band are arranged in ascending order of their corresponding frequencies, then "the third sub-band may be located on the same side of the first and second sub-bands in the frequency domain" can be replaced with: the index of the third sub-band is greater than the index of the first sub-band and the index of the second sub-band, or the index of the third sub-band is less than the index of the first sub-band and the index of the second sub-band. In the example below, assume that all the sub-bands include sub-bands #1 to #6, whose corresponding frequencies in ascending order are sub-band #1, sub-band #2, sub-band #3, sub-band #4, sub-band #5, and sub-band #6.

[0192] For example, in Example 1, the first subband can be subband #1, and the first precoding matrix is ​​the precoding matrix of subband #1; the second subband can be subband #5, and the second precoding matrix is ​​the precoding matrix of subband #5; the third subband is subband #6, and the third precoding matrix is ​​the precoding matrix of subband #6. Subband #6 is located on the same side of subband #1 and subband #5 in the frequency domain. The precoding matrices of subband #1 and subband #5 can be interpolated at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #6; correspondingly, the first device can interpolate the precoding matrices of subband #1 and subband #5 at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #6.

[0193] Optionally, when the third sub-band is located on the same side of the first and second sub-bands in the frequency domain, the first and second sub-bands can be the two sub-bands that are closest to the third sub-band in the frequency domain among the at least one sub-band.

[0194] For example, in Example 1, the first subband can be subband #3, and the first precoding matrix is ​​the precoding matrix of subband #3; the second subband can be subband #5, and the second precoding matrix is ​​the precoding matrix of subband #5; the third subband is subband #6, and the third precoding matrix is ​​the precoding matrix of subband #6. Subband #6 is located on the same side of subband #3 and subband #5 in the frequency domain. The precoding matrices of subband #3 and subband #5 can be interpolated at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #6; correspondingly, the first device can interpolate the precoding matrices of subband #3 and subband #5 at the granularity of stream combination #a1 and stream combination #a2, respectively, to obtain the precoding matrix of subband #6.

[0195] Through this implementation, the precoding matrix of the third sub-band is obtained by interpolating the precoding matrices of the two sub-bands located on the same side of the third sub-band in the frequency domain. This allows for accurate determination of the precoding matrix of the third sub-band, and it can be determined even when the first information does not indicate the precoding matrices of the two sub-bands located on both sides of the third sub-band.

[0196] As mentioned above, the at least one precoding matrix can be used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands. There are various specific implementation methods, such as method b1 and / or method b2. Optionally, method b1 and / or method b2 can also be understood as possible implementations of the statement above that "the first and second precoding matrices can be used to interpolate at the granularity of each of the at least one stream combination to obtain the third precoding matrix."

[0197] Method b1: The first precoding vector and the second precoding vector are used to interpolate to obtain the third precoding vector; correspondingly, the first device can interpolate the first precoding vector and the second precoding vector to obtain the third precoding vector.

[0198] The at least one stream combination may include a second stream combination; the first stream may be any stream in the second stream combination, optionally, the number of streams in the second stream combination is 1, that is, the second stream combination only includes the first stream. The first precoding vector is the precoding vector corresponding to the first stream in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first sub-band in the at least one sub-band; the second precoding vector is the precoding vector corresponding to the first stream in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second sub-band in the at least one sub-band; the third precoding vector is the precoding vector corresponding to the first stream in the third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third sub-band, and the third sub-band is the sub-band other than at least one sub-band among all the sub-bands.

[0199] For example (hereinafter referred to as Example 2), the first stream is the first stream in the stream corresponding to the data transmission. As shown in Figure 4A, the first precoding vector V 11 V is the precoding vector corresponding to the first stream in the precoding matrix of subband #1, i.e., the first precoding vector V. 11 V is the first column vector in the precoding matrix of subband #1; the second precoding vector is V. 31 V is the precoding vector corresponding to the first stream in the precoding matrix of subband #3, i.e., the second precoding vector. 31 V is the first column vector in the precoding matrix of subband #3; the third precoding vector is V. 21 V is the precoding vector corresponding to the first stream in the precoding matrix of subband #2, i.e., the third precoding vector. 21 V is the first column vector in the precoding matrix of subband #2. 11 and V 31 It can be used to obtain V through interpolation. 21 Accordingly, the first device can target V 11 and V 31 Interpolation is performed to obtain V 21 .

[0200] It should be understood that this example uses the first stream in the stream corresponding to data transmission as an example for illustration. The first stream can also be any other stream in the stream corresponding to data transmission, without restriction.

[0201] Optionally, the first and second precoding vectors are used to interpolate to obtain the third precoding vector, which can be understood as: the third precoding vector is obtained by interpolating the first and second precoding vectors.

[0202] It should be understood that this method is illustrated using the second stream combination as an example. For each stream combination in the at least one stream combination, the first device can perform interpolation using method b1 to obtain each column vector in the third precoding matrix, and thus obtain the third precoding matrix. For example, when the granularity of the first stream combination is per-stream, for each stream combination in the at least one stream combination, the first device can perform interpolation using method b1 to obtain each column vector in the third precoding matrix, and thus obtain the third precoding matrix. The specific details of the granularity of the first stream combination can be found in the explanation of the granularity of the first stream combination above, and will not be repeated here.

[0203] In some possible ways, the first precoding vector, the second precoding vector, and the third precoding vector can satisfy the following formulas (1) to (3):

[0204] in, This is the first precoding vector. V is the second precoding vector. t Here, k is the index of the first sub-band, k1 is the index of the second sub-band, t is the index of the third sub-band, cos() is the cosine function, sin() is the sine function, and acos() is the inverse cosine function. for The conjugate transpose of , || represents taking the absolute value, atan() is the arctangent function, Im() represents taking the imaginary part of the complex number, and Re() represents taking the real part of the complex number.

[0205] For example, in Example 2, For V 11 , For V 31 V t For V 21 k0 is the index of subband #1, k1 is the index of subband #3, and t is the index of subband #2. The first device can be based on V 11 V 31 And θ is determined by formula (2), and V is used to determine θ. 11 V 31 And φ is determined by formula (3), so V can be determined according to formula (1). 21 .

[0206] Alternatively, formulas (2) and (3) can be replaced with the following formulas:

[0207] Using method b1, the first device can accurately determine the third precoding vector based on the first and second precoding vectors, thereby accurately determining the third precoding matrix. Furthermore, in this method, the first device can determine the precoding vector corresponding to each stream in the third precoding matrix stream-by-stream, resulting in lower computational complexity.

[0208] Method b2: The first matrix and the second matrix are used to obtain the third matrix through interpolation; correspondingly, the first device can interpolate the first matrix and the second matrix to obtain the third matrix.

[0209] The at least one stream combination may include a third stream combination, and the third stream combination may include multiple streams. The first matrix includes precoding vectors corresponding to the multiple streams in a first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first sub-band among the at least one sub-band; the second matrix includes precoding vectors corresponding to the multiple streams in a second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second sub-band among the at least one sub-band; the third matrix includes precoding vectors corresponding to the multiple streams in a third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third sub-band, which is the sub-band among all sub-bands except for at least one sub-band.

[0210] For example (hereinafter referred to as Example 3), the third stream combination includes the first and second streams in the stream corresponding to the data transmission. As shown in Figure 4B, the first matrix V 12 This includes: the precoding vector corresponding to the first stream in the precoding matrix of subband #1, and the precoding vector corresponding to the second stream in the precoding matrix of subband #1, i.e., the first matrix V. 12 Includes the first and second column vectors in the precoding matrix of subband #1; the second matrix V 32 This includes: the precoding vector corresponding to the first stream in the precoding matrix of subband #3, and the precoding vector corresponding to the second stream in the precoding matrix of subband #3, i.e., the second matrix V. 32 Includes the first and second column vectors in the precoding matrix of subband #3; the third matrix V 22 This includes: the precoding vector corresponding to the first stream in the precoding matrix of subband #2, and the precoding vector corresponding to the second stream in the precoding matrix of subband #2, i.e., the third matrix V. 22 This includes the first and second column vectors in the precoding matrix of subband #2. 12 and V 32 It can be used to obtain V through interpolation. 22 Accordingly, the first device can target V 12 and V 32 Interpolation is performed to obtain V 22 .

[0211] It should be understood that this example illustrates the concept of a third stream combination that includes the first and second streams in the stream corresponding to the data transmission. The third stream combination may also include other streams in the stream corresponding to the data transmission, without limitation.

[0212] Optionally, the first and second matrices are used to obtain the third matrix through interpolation. This can be understood as the third matrix being obtained by interpolating the first and second matrices.

[0213] It should be understood that this method is illustrated using the third stream combination as an example. For each stream combination in the at least one stream combination, the first device can perform interpolation using method b2 to obtain each column vector in the third precoding matrix, thereby obtaining the third precoding matrix. For example, when the granularity of the first stream combination is a stream combination or all streams, for each stream combination in the at least one stream combination, the first device can perform interpolation using method b2 to obtain each column vector in the third precoding matrix, thereby obtaining the third precoding matrix. The specific details of the granularity of the first stream combination can be found in the explanation of the granularity of the first stream combination above, and will not be repeated here.

[0214] In some possible ways, the third matrix V t1 It can satisfy the following formula (4):

[0215] in, and Formula (5) can be satisfied:

[0216] Yes For example, obtained by performing SVD. Satisfies formula (6):

[0217] Formula (7) can be satisfied:

[0218] Γ(x), Ω(x), and F(x) satisfy formulas (8) to (10) respectively: Γ(x)=diag(cos(xθ1),cos(xθ2),…,cos(xθ) p )); (8) Ω(x)=diag(sin(xθ1),sin(xθ2),…,sin(xθ p (9)

[0219] Wherein, B satisfies formula (11): B=A*logm(D)*inv(A); (11)

[0220] Among them, matrices A and D are based on the matrix The eigenvalue decomposition yields, for example, matrices A and D satisfying formula (12):

[0221] In the above formula, For the first matrix, V is the second matrix. t1 Let be the third matrix, k0 be the index of the first sub-band, k1 be the index of the second sub-band, t be the index of the third sub-band, p be the number of the multiple streams, cos() be the cosine function, sin() be the sine function, and (). H Let be the conjugate transpose of the matrix, ...

[0222] For example, in Example 3, For V 12 , For V 32 V t1 For V 22 k0 is the index of subband #1, k1 is the index of subband #3, and t is the index of subband #2. The first device can be determined according to formula V. 12 V 32 Determined by formula (6) and Then, the first device can be based on V 12 V 32 Determined by formula (5) and according to Formulas (7) to (9) determine Γ(x) and Ω(x), according to Formulas (10) to (12) determine F(x), thus allowing us to determine F(x) based on... Γ(x), Ω(x), F(x) and formula (4) determine V 22 .

[0223] Using method b2, the first device can accurately determine the third matrix based on the first and second matrices, thereby accurately determining the third precoding matrix. Furthermore, in this method, the first device can interpolate by combining streams to obtain the third matrix, which reduces computational complexity compared to interpolating for each stream.

[0224] It should be understood that mode b1 and mode b2 can be independent or combined. For example, the third precoding matrix includes the precoding vectors corresponding to streams #1 to #4. The precoding vectors corresponding to streams #1 to #4 in the third precoding matrix can be determined according to mode b1. Another example: the third precoding matrix includes the precoding vectors corresponding to streams #1 to #4. Matrix #1 includes the precoding vectors corresponding to streams #1 to #2 in the third precoding matrix, and matrix #2 includes the precoding vectors corresponding to streams #3 to #4 in the third precoding matrix. Matrix #1 and matrix #2 can be determined according to mode b2. Yet another example: the third precoding matrix includes the precoding vectors corresponding to streams #1 to #4. The precoding vector corresponding to stream #1 in the third precoding matrix can be determined according to mode b1; matrix #3 includes the precoding vectors corresponding to streams #2 to #4 in the third precoding matrix, and matrix #3 can be determined according to mode b2.

[0225] It should be understood that methods b1 and b2 are merely examples, and the first device may also use other methods to interpolate the at least one precoded matrix without limitation.

[0226] In S303, the second information can be carried in a traditional message or in a new message. For example, in scenario 1 above, the second information can be carried in a DCI, MAC CE, or RRC message. As another example, in scenario 2 above, the second information can be carried in a UCI, MAC CE, or RRC message.

[0227] Optionally, the second information may have other names, such as first-stream combination granularity indication information, or first-stream combination granularity information, etc., without limitation.

[0228] This application does not restrict the execution order of S303 with S301 and / or S302. Optionally, S303 may be after S301; the second information and the first information may be carried in the same message or in different messages.

[0229] Using the method shown in Figure 3, the second device can send first information, which can be used to indicate the precoding matrix of a portion of all subbands occupied (or corresponding to, or used) by the reference signal. In this way, the first device can interpolate the precoding matrix of that portion of the subbands to obtain the precoding matrices corresponding to each of all subbands. In this method, the second device does not need to feed back the precoding matrix corresponding to each of all subbands, thereby reducing the overhead of feeding back the precoding matrix.

[0230] When applied to massive MIMO technology, this method can significantly reduce the overhead of the feedback precoding matrix. For example, massive MIMO technology may have a large number of antennas, resulting in a large number of antenna ports. Since the number of rows in the precoding matrix equals the number of transmit antenna ports, the feedback overhead of the precoding matrix for each sub-band increases with the number of antenna ports. This method can feed back only the precoding matrix of a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix. Similarly, massive MIMO technology may have a large bandwidth, resulting in a large number of sub-bands. This method can also feed back only the precoding matrix of a portion of the sub-bands, without feeding back the precoding matrix for each sub-band, thus significantly reducing the overhead of the feedback precoding matrix.

[0231] Alternatively, since the second device may not feed back the precoding matrix for each subband, this method can improve the accuracy of the fed-back precoding matrix without changing the overhead of the fed-back precoding matrix, thereby improving the accuracy of the precoding matrix recovered by the first device.

[0232] Furthermore, in this method, the second information can be used to indicate at least one stream combination; the at least one precoding matrix can be used to interpolate at the granularity of each stream combination to obtain the precoding matrices corresponding to each of the at least one stream combination. In this way, the second information can indicate highly similar streams as a stream combination, thereby improving the accuracy of the interpolated precoding matrix and thus improving transmission performance.

[0233] Among some possible approaches, the method shown in Figure 3 also includes S304:

[0234] S304: The second device sends the third information; correspondingly, the first device receives the third information.

[0235] The third information can be used to indicate (or configure, or determine) one or more stream combinations; correspondingly, the first device can determine the one or more stream combinations based on the third information. Each of the one or more stream combinations includes one or more streams; the one or more stream combinations are combinations of streams corresponding to the at least one precoding matrix.

[0236] Optionally, the third information can be used to indicate (or configure, or determine) one or more stream combinations, which can be understood as at least one of the following: the third information can be used to indicate (or configure, or determine) one or more stream combinations corresponding to a precoding matrix; the third information can be used to indicate (or configure, or determine) one or more stream combinations as the granularity of stream combination of a precoding matrix; or, the third information can be used to indicate (or configure, or determine) the granularity of stream combination corresponding to the at least one precoding matrix.

[0237] The following section will first explain the combination of one or more streams.

[0238] Optionally, the different flow combinations in the one or more flow combinations may include the same or different numbers of flows. For example, the one or more flow combinations may include flow combinations #b1 to #b2. Flow combination #b1 includes flows #1 to #4; flow combination #b2 includes flows #5 to #8. As another example, the one or more flow combinations may include flow combinations #b1 to #b2. Flow combination #b1 includes flows #1 to #2; flow combination #b2 includes flows #3 to #8.

[0239] Optionally, the fourth flow combination can be any one of the one or more flow combinations. When the fourth flow combination includes multiple flows, the indices of the multiple flows can be continuous or discontinuous; in other words, when the fourth flow combination includes multiple flows, the multiple flows can be continuous or discontinuous; or, the indices of the flows in each of the one or more flow combinations can be continuous or discontinuous. For example, the one or more flow combinations include flow combinations #b1 to #b2. Flow combination #b1 includes flows #1 to #4; flow combination #b2 includes flows #5 to #8. As another example, the one or more flow combinations include flow combinations #b1 to #b2. Flow combination #b1 includes flows #1, #3, #5, and #7; flow combination #b2 includes flows #2, #4, #6, and #8.

[0240] In some implementations, the one or more stream combinations may be determined based on the similarity between different streams; correspondingly, the second device may determine the one or more stream combinations based on the similarity between different streams. For example, the similarity between different streams in each of the one or more stream combinations is high. Optionally, the one or more stream combinations may be determined based on the similarity between different streams, which can be understood as at least one of the following: the one or more stream combinations may be determined based on the similarity between different precoding vectors corresponding to different streams, and correspondingly, the second device may determine the one or more stream combinations based on the similarity between different precoding vectors corresponding to different streams; or, the one or more stream combinations may be determined based on the similarity between different channels corresponding to different streams, and correspondingly, the second device may determine the one or more stream combinations based on the similarity between different channels corresponding to different streams.

[0241] Optionally, the similarity between different streams can be determined based on the cosine similarity and / or NMSE between different channels corresponding to different streams; correspondingly, the combination of one or more streams can be determined based on the similarity between different streams, but this can be replaced by: the combination of one or more streams can be determined based on the cosine similarity and / or NMSE between different channels corresponding to different streams. Optionally, the cosine similarity and / or NMSE between different channels corresponding to different streams can be replaced by: the cosine similarity and / or NMSE between different precoding vectors corresponding to different streams.

[0242] In some examples, if the cosine similarity between different channels corresponding to different flows is greater than or equal to a third threshold, then the different flows can belong to one of the one or more flow combinations. For example, the flows corresponding to data transmission include flows #1 to #8. If the cosine similarity between different channels corresponding to any two flows in flows #1 to #4 is greater than or equal to the third threshold, then flows #1 to #4 can belong to flow combination #b1 in one or more flow combinations; if the cosine similarity between different channels corresponding to any two flows in flows #5 to #8 is greater than or equal to the third threshold, then flows #5 to #8 can belong to flow combination #b2 in one or more flow combinations.

[0243] In other examples, if the NMSE between different channels corresponding to different flows is less than or equal to a fourth threshold, then the different flows may belong to one of the one or more flow combinations. For example, the flows corresponding to data transmission include flows #1 to #8. If the NMSE between different channels corresponding to any two flows from flows #1 to #4 is less than or equal to the fourth threshold, then flows #1 to #4 may belong to flow combination #b1 in one or more flow combinations; if the NMSE between different channels corresponding to any two flows from flows #5 to #8 is less than or equal to the fourth threshold, then flows #5 to #8 may belong to flow combination #b2 in one or more flow combinations.

[0244] In some other examples, if the cosine similarity between different channels corresponding to different flows is greater than or equal to a third threshold, and the NMSE between different channels corresponding to the different flows is less than or equal to a fourth threshold, then the different flows can belong to one of the one or more flow combinations. For example, the flows corresponding to data transmission include flows #1 to #8. If the cosine similarity between different channels corresponding to every two flows from flows #1 to #4 is greater than or equal to the third threshold, and the NMSE between different channels corresponding to every two flows from flows #1 to #4 is less than or equal to the fourth threshold, then flows #1 to #4 can belong to flow combination #b1 in one or more flow combinations; if the cosine similarity between different channels corresponding to every two flows from flows #5 to #8 is greater than or equal to the third threshold, and the NMSE between different channels corresponding to every two flows from flows #5 to #8 is less than or equal to the fourth threshold, then flows #5 to #8 can belong to flow combination #b2 in one or more flow combinations.

[0245] The third and / or fourth thresholds may be pre-set, such as those specified in the protocol; or they may be notified to the first device by other devices (e.g., core network equipment or a second device); or they may be determined by the first device.

[0246] In other implementations, it is pre-set (e.g., specified by the protocol) or defaulted to: the one or more stream combinations constitute a single stream combination, which includes all streams corresponding to data transmission. Optionally, in this implementation, S304 is an optional step. For example, the method shown in FIG3 includes S304, in which the second device can determine and send third information; correspondingly, the first device can determine the one or more stream combinations based on the third information. Yet another example is that the method shown in FIG3 does not include S304, and the first device can determine, based on pre-set or default settings, that the one or more stream combinations constitute a single stream combination, which includes all streams corresponding to data transmission.

[0247] In some implementations, the first flow combination is any flow combination among the at least one flow combination, and all flows of the first flow combination belong to one of the one or more flow combinations.

[0248] Optionally, the first flow combination is any flow combination among the at least one flow combination, and all flows of the first flow combination belong to one of the one or more flow combinations. This can be understood as at least one of the following: all flows in each flow combination of the at least one flow combination belong to one of the one or more flow combinations; the number of flows in each flow combination of the at least one flow combination is less than the number of flows in each flow combination of the one or more flow combinations; or, the granularity of the at least one flow combination is finer than the granularity of the one or more flow combinations.

[0249] For example, the at least one flow combination includes flow combination #a1 and flow combination #a2. Flow combination #a1 includes: flow #1, flow #2, flow #3, and flow #4; flow combination #a2 includes: flow #5, flow #6, flow #7, and flow #8. The one or more flows include flow combination #b1 and flow combination #b2. Flow combination #b1 includes: flow #1, flow #2, flow #3, and flow #4; flow combination #b2 includes: flow #5, flow #6, flow #7, and flow #8. All flows in flow combination #a1 belong to flow combination #b2, and all flows in flow combination #a2 belong to flow combination #b2.

[0250] For example, the at least one flow combination includes flow combination #a1 and flow combination #a2. Flow combination #a1 includes: flow #1, flow #2, flow #3, and flow #4; flow combination #a2 includes: flow #5, flow #6, flow #7, and flow #8. The one or more flows include flow combination #b1. Flow combination #b1 includes: flow #1, flow #2, flow #3, flow #4, flow #5, flow #6, flow #7, and flow #8. All flows in flow combination #a1 belong to flow combination #b1, and all flows in flow combination #a2 belong to flow combination #b1.

[0251] In this manner, all streams in each stream combination used for interpolation belong to one of the stream combinations corresponding to the at least one precoding matrix; thus, the first device can accurately determine the precoding matrix corresponding to each subband based on the at least one precoding matrix with each stream combination in the at least one stream combination as the granularity.

[0252] Optionally, the at least one stream combination and the one or more stream combinations may be the same or different. When the at least one stream combination and the one or more stream combinations are the same, the second information and the third information may be the same information or different information. When the second information and the third information are the same information, S303 and S304 may be combined into: the second device sends the second information; correspondingly, the first device receives the second information. The second information may indicate the at least one stream combination and the one or more stream combinations.

[0253] As mentioned above, the third information can be used to indicate the combination of one or more streams, and the indication can be in various ways, such as mode c1 and / or mode c2.

[0254] Method c1: The third information can be used to indicate O, where O is the number of streams included in each of the one or more stream combinations, and O is a positive integer. The q-th stream combination in the one or more stream combinations includes the 1+(q-1)*O to the O+(q-1)*O streams in the stream corresponding to (or used for) data transmission, where q is a positive integer. q can take any integer from 1 to Q, where Q is the number of stream combinations in the one or more stream combinations.

[0255] Optionally, in mode c1, the number of flows included in different flow combinations in the one or more flow combinations is the same, that is, the number of flows included in each flow combination in the one or more flow combinations is 0.

[0256] Optionally, the third information can be used to indicate O, which can be understood as: the third information can be used to indicate the second stream combination granularity, which can be the stream combination granularity corresponding to the precoding matrix (or precoding matrix indication (e.g., PMI or TPMI)). For example, the second stream combination granularity can be the stream combination granularity corresponding to the precoding matrix (or precoding matrix indication (e.g., PMI or TPMI)) of a subband, or the second stream combination granularity can be the stream combination granularity corresponding to the at least one precoding matrix. Exemplarily, the second stream combination granularity can be one of the following: stream-by-stream, stream combination, or all streams. It should be understood that when the second stream combination granularity is stream-by-stream, each stream combination in the one or more stream combinations includes one stream; when the second stream combination granularity is stream combination, each stream combination in the one or more stream combinations includes multiple streams; when the second stream combination granularity is all streams, the one or more stream combinations can be a single stream combination that includes all streams, wherein the all streams are, for example, all streams corresponding to (or used) data transmission (e.g., uplink data transmission). It should be understood that the second flow combination granularity of all flows can be an example of the second flow combination granularity of flow combination.

[0257] In some implementations, there is a correspondence between the value of the third information and the value of O (hereinafter referred to as the second correspondence); the first device can determine the value of O based on the value of the third information and the second correspondence, thereby determining the one or more stream combinations. For example, all streams corresponding to (or used) the data transmission include streams #1 to #8, and the second correspondence is shown in Table 3A; the first device can determine the value of O and the one or more stream combinations based on the value of the third information.

[0258] Table 3A

[0259] It should be understood that Table 3A is merely an example and is not intended to limit the scope of protection of this application. In practical applications, Table 3A may also have other variations. For example, it may include more or fewer rows and / or columns. Table 3A may also be transformed into Table 3B.

[0260] Table 3B

[0261] It should be understood that Table 3B is merely an example and is not intended to limit the scope of protection of this application. In practical applications, Table 3B may also be modified in other ways, such as including more or fewer rows and / or columns.

[0262] Optionally, the second correspondence may be pre-set, such as as specified in an agreement; or it may be notified to the first device by other devices (e.g., core network equipment or a second device); or it may be determined by the first device.

[0263] In this method c1, when the third information indicates O, the first device can accurately determine the one or more flow combinations based on the value of O. Furthermore, in this method, the third information can indirectly indicate the one or more flow combinations by indicating O, and the overhead required for the third information is relatively small, thereby reducing signaling overhead.

[0264] Method c2: The fourth stream combination is any one of one or more stream combinations, and the third information may include the index of each stream in the fourth stream combination.

[0265] Optionally, method c2 can be understood as follows: for each of the one or more stream combinations, the third information may include the index of each stream in the stream combination.

[0266] For example, the one or more stream combinations include stream combination #b1 and stream combination #b2. For stream combination #b1, if the third information includes indices of stream #1, stream #3, stream #5, and stream #7, then stream combination #b1 includes stream #1, stream #3, stream #5, and stream #7. For stream combination #b2, if the third information includes indices of stream #2, stream #4, stream #6, and stream #8, then stream combination #b1 includes stream #2, stream #4, stream #6, and stream #8.

[0267] Through this method c2, the third information can accurately indicate the fourth stream combination. Furthermore, in this method, the third information can include the index of each stream in the fourth stream combination, so that the streams in the fourth stream combination can be continuous or discontinuous, thereby expanding the scope of application.

[0268] In S304, the third information can be carried in a traditional message or in a new message. For example, in scenario 1 above, the third information can be carried in a DCI, MAC CE, or RRC message. As another example, in scenario 2 above, the third information can be carried in a UCI, MAC CE, or RRC message.

[0269] Optionally, the third information may have other names, such as second stream combination granularity indication information, or second stream combination granularity information, etc., without limitation.

[0270] This application does not restrict the execution order of steps S304 and any of S301 to S303. Optionally, S304 may be after S301. Any two of the first, second, and third information may be carried in the same message or in different messages.

[0271] In this way, the third information can accurately indicate one or more stream combinations corresponding to the at least one precoding matrix.

[0272] In some possible ways, before interpolating the at least one precoding matrix, the first device may determine that the at least one precoding matrix should be interpolated, and there are various ways to determine this, such as mode d1 or mode d2.

[0273] Method d1:

[0274] The method shown in Figure 3 also includes S305:

[0275] S305: The second device sends the first instruction information; correspondingly, the first device receives the first instruction information.

[0276] The first indication information can be used to instruct (or configure) the first device to interpolate the precoding matrices of a portion of the subbands in all subbands. Thus, the first device can determine, based on the first indication information, whether to interpolate at least one precoding matrix.

[0277] Optionally, the first indication information can be used to instruct (or configure) the first device to interpolate the precoding matrix of a portion of the subbands in all subbands using a manifold interpolation method. Thus, the first device can determine, based on the first indication information, to interpolate the at least one precoding matrix using a manifold interpolation method.

[0278] Optionally, the first indication information can be used to instruct (or configure) the first device to interpolate the precoding matrix of some subbands in all subbands. This can be understood as: the first indication information is used to instruct (or configure) the first device to obtain the precoding matrix corresponding to each of all subbands through interpolation.

[0279] The first indication information can be carried in a traditional message or in a new message, without restriction. For example, in scenario 1 above, the first indication information can be carried in a DCI, MAC CE, or RRC message. As another example, in scenario 2 above, the first indication information can be carried in a UCI, MAC CE, or RRC message.

[0280] The first indication information may have other names, such as interpolation indication information or manifold interpolation indication information, without restriction.

[0281] This application does not restrict the execution order of any of the steps S305 and S301 to S304; any two of the first instruction information, first information, second information and third information can be carried in the same message or in different messages.

[0282] In this method d1, the first device accurately determines the at least one precoding matrix to be interpolated based on the first instruction information. Furthermore, in this method, the first device can interpolate the at least one precoding matrix based on instructions from the second device, thereby improving the effectiveness and flexibility of the second device's management of the first device.

[0283] Method d2: Pre-defined, for example, according to the protocol, interpolation is performed on the precoding matrices of a portion of all subbands. In this way, the first device can determine whether to interpolate the at least one precoding matrix.

[0284] For example, it is pre-defined, for instance, by a protocol, that the precoding matrices of a portion of the subbands in all subbands are interpolated using a manifold interpolation method. Thus, the first device can determine that the at least one precoding matrix should be interpolated using a manifold interpolation method.

[0285] Using this method d2, the first device can accurately determine whether to interpolate the at least one precoding matrix. Furthermore, since the interpolation of the precoding matrices for a portion of all subbands is pre-defined in this method, the first and second devices do not need to transmit information indicating the interpolation of the precoding matrices for a portion of all subbands, thereby reducing signaling overhead.

[0286] In some possible ways, before interpolating the at least one precoding matrix, the first device may determine at least one subband corresponding to the at least one precoding matrix, and there are various ways to determine it, such as at least one of modes e1 to e3.

[0287] Method e1:

[0288] The method shown in Figure 3 also includes:

[0289] S306: The second device sends a second instruction message; correspondingly, the first device receives the second instruction message.

[0290] The second indication information can be used to indicate (or configure) at least one of the following: the at least one sub-band, or the number of sub-bands in the at least one sub-band. For example, the second indication information can indicate the at least one sub-band. Alternatively, the second indication information can indicate: the at least one sub-band, and the number of sub-bands in the at least one sub-band. This application does not limit the manner in which the second indication information is indicated; for example, it can be explicitly indicated or implicitly indicated.

[0291] In some implementations, for each stream corresponding to data transmission, the second indication information may indicate at least one of the following for that stream: at least one subband, or the number of subbands in at least one subband. For example, the streams corresponding to data transmission include streams #1 to #3. For stream #1, the second indication information may indicate subbands #1, #3, and #5; correspondingly, the second device may feed back the precoding vector corresponding to stream #1 in the precoding matrix of subband #1, the precoding vector corresponding to stream #1 in the precoding matrix of subband #3, and the precoding vector corresponding to stream #1 in the precoding matrix of subband #5 through the first information feedback. For stream #2, the second indication information may indicate subbands #1 and #5; correspondingly, the second device may feed back the precoding vector corresponding to stream #2 in the precoding matrix of subband #1, and the precoding vector corresponding to stream #2 in the precoding matrix of subband #5 through the first information feedback. For stream #3, the second indication information can indicate subband #1, subband #3 and subband #5; correspondingly, the second device can feed back the precoding vector corresponding to stream #3 in the precoding matrix of subband #1 through the first information, feed back the precoding vector corresponding to stream #3 in the precoding matrix of subband #3 through the first information, and feed back the precoding vector corresponding to stream #3 in the precoding matrix of subband #5 through the first information.

[0292] In other implementations, for each stream combination corresponding to data transmission, the second indication information may indicate at least one of the following for each stream combination: at least one subband, or the number of subbands in at least one subband. For example, the streams corresponding to data transmission include streams #1 to #3. For a stream combination including streams #1 and #2, the second indication information may indicate subbands #1, #3, and #5; correspondingly, the second device may feed back the precoding vectors corresponding to streams #1 and #2 in the precoding matrix of subband #1, the precoding vectors corresponding to streams #1 and #2 in the precoding matrix of subband #3, and the precoding vectors corresponding to streams #1 and #2 in the precoding matrix of subband #5. For stream #3, the second indication information may indicate subbands #1 and #5; correspondingly, the second device may feed back the precoding vectors corresponding to stream #3 in the precoding matrix of subband #1 and the precoding vectors corresponding to stream #3 in the precoding matrix of subband #5.

[0293] In some implementations, for all streams corresponding to uplink data transmission, the second indication information may indicate at least one of the following: at least one subband, or the number of subbands in at least one subband. For example, the streams corresponding to uplink data transmission include streams #1 to #3. If the second indication information can indicate subband #1, subband #3, and subband #5, then the second device can feed back the precoding vectors corresponding to streams #1 to #3 in the precoding matrix of subband #1 through the first information, feed back the precoding vectors corresponding to streams #1 to #3 in the precoding matrix of subband #3 through the first information, and feed back the precoding vectors corresponding to streams #1 to #3 in the precoding matrix of subband #5 through the first information.

[0294] In S306, the second indication information can be carried in a conventional message or in a new message. For example, in scenario 1 above, the second indication information can be carried in a DCI, MAC CE, or RRC message. As another example, in scenario 2 above, the second indication information can be carried in a UCI, MAC CE, or RRC message.

[0295] The second instruction information may have other names, such as sub-band instruction information, etc., without restriction.

[0296] This application does not restrict the execution order of any step S306 and S301 to S305. Optionally, S306 may be after S301. Any two of the first instruction information, second instruction information, first information, second information and third information may be carried in the same message or in different messages.

[0297] Through this method e1, the first device can accurately determine the at least one sub-band and / or the number of sub-bands in the at least one sub-band according to the second instruction information. Furthermore, in this method, the at least one sub-band and / or the number of sub-bands in the at least one sub-band can be indicated by the second device, thereby improving the effectiveness and flexibility of the second device's management of the first device.

[0298] Method e2: Pre-defined, for example, as specified in the protocol: the at least one subband and / or the number of subbands in the at least one subband.

[0299] Through this method e2, the first device can accurately determine the at least one sub-band and / or the number of sub-bands in the at least one sub-band. Furthermore, in this method, the at least one sub-band and / or the number of sub-bands in the at least one sub-band are preset, thus eliminating the need for transmission of information indicating the at least one sub-band and / or the number of sub-bands between the first and second devices, thereby saving signaling overhead.

[0300] Method e3: The at least one sub-band and / or the number of sub-bands in at least one sub-band may be related to at least one of the following; in other words, the at least one sub-band and / or the number of sub-bands in at least one sub-band may correspond to at least one of the following (hereinafter referred to as the third correspondence): the number of transmitting antennas of the first device; the number of receiving antennas of the second device; the number of sub-bands in all sub-bands; the number of streams corresponding to data transmission; the rate of change of the channel in the frequency domain; or, the degree of change of the channel in the frequency domain. Wherein, the first device is a first apparatus or a device using the first apparatus, for example, the first device is a terminal; the second device is a second apparatus or a device using the second apparatus, for example, the second device is an access network device. For example, the at least one sub-band and / or the number of sub-bands in at least one sub-band may be related to the number of sub-bands in all sub-bands and the number of streams corresponding to data transmission. Also, for example, the at least one sub-band and / or the number of sub-bands in at least one sub-band may be related to the number of sub-bands in all sub-bands, the number of streams corresponding to data transmission, and the rate of change of the channel in the frequency domain. For example, the number of sub-bands in the at least one sub-band and / or at least one sub-band may be related to the number of sub-bands in all sub-bands, the number of streams corresponding to data transmission, and the degree of channel variation in the frequency domain. For example, the number of sub-bands in the at least one sub-band and / or at least one sub-band may be related to the rate of channel variation in the frequency domain. For example, the number of sub-bands in the at least one sub-band and / or at least one sub-band may be related to the degree of channel variation in the frequency domain. Thus, the first device can determine the number of sub-bands in the at least one sub-band and / or at least one sub-band according to the third correspondence; and / or, the second device can determine the number of sub-bands in the at least one sub-band and / or at least one sub-band according to the third correspondence. Optionally, after determining the number of sub-bands in the at least one sub-band and / or at least one sub-band, the second device can execute S306 above.

[0301] 1. The number of subbands in at least one subband:

[0302] Optionally, the number of subbands in the at least one subband may be positively correlated with the number of subbands in all subbands. For example, the larger the number of subbands in all subbands, the larger the number of subbands in the at least one subband; and / or, the smaller the number of subbands in all subbands, the smaller the number of subbands in the at least one subband.

[0303] Optionally, for streams with later indices (or sequence numbers, or serial numbers), the number of streams corresponding to data transmission can be positively correlated with the number of subbands in the at least one subband corresponding to that stream. For example, the larger the number of streams corresponding to data transmission, the larger the number of subbands in the at least one subband corresponding to a stream with later indices (or sequence numbers, or serial numbers); and / or, the smaller the number of streams corresponding to data transmission, the smaller the number of subbands in the at least one subband corresponding to a stream with later indices (or sequence numbers, or serial numbers).

[0304] Optionally, the number of sub-bands in the at least one sub-band may be positively correlated with the rate of change of the channel in the frequency domain. For example, the faster the channel changes in the frequency domain, the larger the number of sub-bands in the at least one sub-band; and / or, the slower the channel changes in the frequency domain, the smaller the number of sub-bands in the at least one sub-band.

[0305] Optionally, the number of sub-bands in the at least one sub-band may be positively correlated with the degree of channel variation in the frequency domain. For example, the greater the degree of channel variation in the frequency domain, the greater the number of sub-bands in the at least one sub-band; and / or, the smaller the degree of channel variation in the frequency domain, the smaller the number of sub-bands in the at least one sub-band.

[0306] 2. For at least one sub-band:

[0307] Optionally, the sub-bands in the at least one sub-band may be related to the rate of change of the channel in the frequency domain. For example, the faster the rate of change of the channel in the frequency domain, the denser the distribution of the at least one sub-band in the frequency domain (or, the smaller the spacing between adjacent sub-bands in the frequency domain); and / or, the slower the rate of change of the channel in the frequency domain, the sparser the distribution of the at least one sub-band in the frequency domain (or, the larger the spacing between adjacent sub-bands in the frequency domain).

[0308] Optionally, the sub-bands in the at least one sub-band may be related to the degree of variation of the channel in the frequency domain. For example, the greater the degree of variation of the channel in the frequency domain, the denser the distribution of the at least one sub-band in the frequency domain (or, the smaller the interval between adjacent sub-bands in the frequency domain); and / or, the smaller the degree of variation of the channel in the frequency domain, the sparser the distribution of the at least one sub-band in the frequency domain (or, the larger the interval between adjacent sub-bands in the frequency domain).

[0309] The rate of change and / or degree of change of the channel in the frequency domain are related to the similarity between different sub-bands. The faster the channel changes in the frequency domain, and / or the greater the degree of change, the lower the similarity between different sub-bands (e.g., between adjacent sub-bands); conversely, the slower the channel changes in the frequency domain, and / or the smaller the degree of change, the higher the similarity between different sub-bands (e.g., between adjacent sub-bands). Thus, the first and / or second devices can balance the similarity between different sub-bands and the number of sub-bands corresponding to the feedback precoding matrix, thereby minimizing the number of sub-bands corresponding to the feedback precoding matrix and reducing the overhead of the feedback precoding matrix while ensuring the accuracy and precision of interpolation.

[0310] In some implementations, the at least one subband may be selected from all the subbands based on the number of subbands in the at least one subband.

[0311] In some examples, the i-th sub-band among at least one sub-band can be the i-th sub-band among all sub-bands. i is a positive integer. This indicates rounding down. For example, if all subbands include 8 subbands, and the number of subbands in the at least one subband is 3, then the at least one subband includes the first, fourth, and seventh subbands of all subbands.

[0312] In other examples, if the number of subbands in the at least one subband is 2, then the at least one subband can be the first and last subbands among all the subbands.

[0313] In some examples, if the number of subbands in the at least one subband is greater than 2, then the at least one subband may include the first and last subbands of all subbands. The fourth subband is any subband in the at least one subband other than the first and last subbands of all subbands; the fourth subband is the *a*-th subband in the at least one subband, where *a* is a positive integer. The fourth subband can be the *a*-th subband among all subbands. Subband. For example, if all subbands include 8 subbands, and the number of subbands in the at least one subband is 3, then the at least one subband includes the first, fourth, and eighth subbands of all subbands.

[0314] The following provides examples of the at least one subband and / or the number of at least one subband.

[0315] In some examples, if the number of transmitting antennas of the first device is greater than 8, the number of receiving antennas of the second device is greater than or equal to 256, the number of subbands in all subbands is less than or equal to 13, and the number of streams corresponding to data transmission is less than or equal to 4, then the number of subbands in the at least one subband is 2, and / or the at least one subband can be the first subband and the last subband in all subbands.

[0316] In other examples, if the number of transmit antennas of the first device is greater than 8, the number of receive antennas of the second device is greater than or equal to 256, the number of subbands in all subbands is greater than 13 and less than or equal to 26, and the number of streams corresponding to data transmission is less than or equal to 4, then the number of subbands in the at least one subband is 3, and / or the at least one subband can be the first subband, the second subband, or the third subband in all subbands. The first sub-band and the last sub-band.

[0317] In some other examples, if the number of transmit antennas of the first device is greater than 8, the number of receive antennas of the second device is greater than or equal to 256, the number of subbands in all subbands is greater than 26, and the number of streams corresponding to data transmission is less than or equal to 4, then the number of subbands in the at least one subband is 4, and / or the at least one subband can be the first subband, the second subband, or the third subband in all subbands. Individual belt, first The first sub-band and the last sub-band.

[0318] It should be understood that the above examples can be independent or combined with each other.

[0319] The third correspondence can be pre-set, such as as specified in an agreement; or it can be determined by the first device; or it can be notified to the first device by other devices (such as core network equipment or the second device).

[0320] In this manner, the first device and / or the second device can accurately determine the number of sub-bands in the at least one sub-band and / or at least one sub-band based on the third correspondence. Furthermore, in this manner, if the first device determines the number of sub-bands in the at least one sub-band and / or at least one sub-band based on the third correspondence, the second device may not need to indicate the number of sub-bands in the at least one sub-band and / or at least one sub-band, thereby reducing signaling overhead. Moreover, in this manner, the number of sub-bands in the at least one sub-band and / or at least one sub-band can be determined by the first device, thereby improving the operational flexibility of the first device.

[0321] Among some possible approaches, the method shown in Figure 3 also includes S307:

[0322] S307: The first device sends a first signal; correspondingly, the second device receives the first signal.

[0323] The first signal is transmitted according to precoding matrix #1; or, the first device may transmit the first signal according to precoding matrix #1. Precoding matrix #1 may be determined based on the precoding matrices of some or all of the sub-bands; or, the first device may determine precoding matrix #1 based on the precoding matrices of some or all of the sub-bands. For example, if the first signal is transmitted through some of the sub-bands, precoding matrix #1 may be determined based on those sub-bands. Or, for example, if the first signal is transmitted through all of the sub-bands, precoding matrix #1 may be determined based on all of the sub-bands. Furthermore, the granularity of precoding performed by the first device may be the same as or different from the granularity of the sub-bands, without limitation.

[0324] Optionally, the first signal may be an uplink signal, for example, the first signal may be PUSCH.

[0325] Optionally, S307 may be performed after one or more of steps S301 to S306.

[0326] Based on the same technical concept as the above-described method embodiments, this application provides a corresponding communication device that can be used to perform the functions of the relevant steps in the above-described method embodiments. This function can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. The communication device can be a terminal or access network device, or it can be a device that can be applied to a terminal or access network device (e.g., a module, communication module, circuit or chip responsible for communication functions (such as a modem chip, or a SoC chip or SIP chip containing a modem core), chip system, or processor), or it can be a logical node, logical module, or software that can implement all or part of the functions of a terminal or access network device. The device that can be applied to a terminal or access network device can exist independently; for example, it can be independently manufactured, sold, or used.

[0327] In one possible implementation, the communication device provided in this embodiment of the application has the structure shown in FIG5, including a processing unit 502. Optionally, the communication device further includes an interface unit 501. The functions of each unit in the communication device 500 are described below.

[0328] Interface unit 501 is used for inputting and / or outputting information. Input information can be replaced by received information, and output information can be replaced by transmitted information. When outputting information, interface unit 501 can output information to other devices outside of communication device 500, or to other units within communication device 500. In some embodiments, interface unit 501 can be implemented through at least one of a physical interface, a communication module, a communication interface, and an input / output interface. In other embodiments, interface unit 501 can be implemented through an interface circuit, such as a mobile communication module. The mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. Interface unit 501 is used to perform the receiving and transmitting operations in the above method embodiments.

[0329] In this application, the interface unit 501 may also have other names, such as a transceiver unit or a communication unit. Optionally, the interface unit 501 may include a receiving unit and / or a sending unit, used for inputting information and outputting information, respectively. The receiving unit is used to perform the receiving operation in the above method embodiments. The sending unit is used to perform the sending operation in the above method embodiments.

[0330] The processing unit 502 can be used to support the communication device 500 in performing the processing actions in the above method embodiments. The processing unit 502 can be implemented by one or more processors. For example, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microprocessors (MCUs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor. The processing unit 502 is used to perform processing-related operations in the above method embodiments, for example, to instruct operations other than receiving and sending operations in the above method embodiments.

[0331] In one embodiment, the communication device 500 is applied to the first device in the embodiment of this application shown in FIG3. The specific functions of the processing unit 502 in this embodiment will be described below.

[0332] Processing unit 502 is configured to: send a reference signal through interface unit 501; receive first information through interface unit 501, the first information indicating at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix including the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; and receive second information through interface unit 501, the second information indicating at least one stream combination, each stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each stream combination in at least one stream combination to obtain the precoding matrices corresponding to each subband respectively.

[0333] In some possible ways, at least one stream combination includes a second stream combination, the first stream being any stream in the second stream combination, and the processing unit 502 is specifically used to: interpolate the first precoding vector and the second precoding vector to obtain a third precoding vector; wherein, the first precoding vector is the precoding vector corresponding to the first stream in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first sub-band in at least one sub-band; the second precoding vector is the precoding vector corresponding to the first stream in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second sub-band in at least one sub-band; the third precoding vector is the precoding vector corresponding to the first stream in the third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third sub-band, and the third sub-band is the sub-band other than at least one sub-band among all sub-bands.

[0334] In some other possible embodiments, at least one stream combination includes a third stream combination, which includes multiple streams. The processing unit 502 is specifically used to: interpolate the first matrix and the second matrix to obtain a third matrix; wherein the first matrix includes precoding vectors corresponding to multiple streams in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first subband in at least one subband; the second matrix includes precoding vectors corresponding to multiple streams in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second subband in at least one subband; the third matrix includes precoding vectors corresponding to multiple streams in the third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third subband, which is the subband of all subbands except for at least one subband.

[0335] In some possible ways, the processing unit 502 is also configured to: receive third information through the interface unit 501, the third information being used to indicate one or more stream combinations, each of the one or more stream combinations including one or more streams, the one or more stream combinations being a combination of streams corresponding to at least one precoding matrix.

[0336] Optionally, the processing unit 502 is further configured to: receive first indication information through the interface unit 501, the first indication information being used to instruct the interpolation of the precoding matrix of a portion of the subbands in all subbands.

[0337] Optionally, the processing unit 502 is further configured to: receive second indication information through the interface unit 501, the second indication information being used to indicate at least one of the following: at least one sub-band, or the number of sub-bands in at least one sub-band.

[0338] In another embodiment, the communication device 500 is applied to the second device in the embodiment of this application shown in FIG3. The specific functions of the processing unit 502 in this embodiment will be described below.

[0339] Processing unit 502 is configured to: receive a reference signal through interface unit 501; send first information through interface unit 501, the first information indicating at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix including the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; and send second information through interface unit 501, the second information indicating at least one stream combination, each stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each stream combination in at least one stream combination to obtain the precoding matrices corresponding to each subband respectively.

[0340] In some possible ways, the processing unit 502 is also configured to: send third information through the interface unit 501, the third information being used to indicate one or more stream combinations, each of the one or more stream combinations including one or more streams, the one or more stream combinations being a combination of streams corresponding to at least one precoding matrix.

[0341] Optionally, the processing unit 502 is further configured to: send first indication information through the interface unit 501, the first indication information being used to instruct the interpolation of the precoding matrix of some subbands in all subbands.

[0342] Optionally, the processing unit 502 is further configured to: send second indication information through the interface unit 501, the second indication information being used to indicate at least one of the following: at least one sub-band, or the number of sub-bands in at least one sub-band.

[0343] In one possible design, when the communication device 500 is a communication equipment or a communication module within a communication equipment, the functionality of the processing unit 502 can be implemented by one or more processors. For example, the processor may include a modem chip, or a system-on-a-chip (SoC) or SIP chip containing a modem core. The functionality of the interface unit 501 can be implemented by transceiver circuitry.

[0344] In one possible design, when the communication device 500 is a circuit or chip responsible for communication functions in a communication device, such as a modem chip or a system-on-a-chip (SoC) or SIP chip containing a modem core, the function of the processing unit 502 can be implemented by a circuit system in the aforementioned chip that includes one or more processors or processor cores. The function of the interface unit 501 can be implemented by the interface circuit or data transceiver circuit on the aforementioned chip.

[0345] The communication device can be a terminal or an access network device.

[0346] A more detailed description of the processing unit 502 and the interface unit 501 can be obtained directly from the relevant description in the method embodiment shown in Figure 3, and will not be repeated here.

[0347] It should be noted that the module division in the above embodiments of this application is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, exist as separate physical units, or have two or more units integrated into one unit. The integrated units can be implemented in hardware, as software functional units, or in a combination of hardware and software. Whether a function is executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art 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.

[0348] For example, the functional unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, such as one or more ASICs, one or more CPUs, one or more MCUs, one or more DSPs, or one or more FPGAs, or a combination of at least two of these integrated circuit forms.

[0349] If the integrated units described above are implemented as 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 this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0350] In one possible implementation, the communication device provided in this application embodiment is shown in FIG6. The communication device 600 includes a processor 602. Optionally, the communication device 600 further includes an interface circuit 601 and a memory 603. The interface circuit 601, the processor 602, and the memory 603 are coupled to each other.

[0351] Optionally, the interface circuit 601, processor 602, and memory 603 are coupled to each other via bus 604. Bus 604 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of illustration, only one thick line is used in Figure 6, but this does not mean that there is only one bus or one type of bus.

[0352] Interface circuit 601 is used for inputting and / or outputting information. Input information can be replaced by received information, and output information can be replaced by transmitted information. When outputting information, interface circuit 601 can output information to other devices outside of communication device 600, or to other units within communication device 600. For example, interface circuit 601 can be implemented through at least one of a physical interface, a communication module, a communication interface, an input / output interface, and a mobile communication module. The mobile communication module may include one or more of at least one antenna, at least one filter, a switch, a power amplifier, an LNA, etc. Interface circuit 601 is used to perform the receiving and transmitting operations in the above method embodiments.

[0353] Interface circuit 601 may be one of the following: a transceiver, a transceiver circuit, a communication circuit, an interface, a communication interface, or an input / output interface (e.g., a chip's input / output interface). Interface circuit 601 may include an input interface circuit and an output interface circuit, used for inputting information and outputting information, respectively. The input interface circuit is used to perform the receiving operation in the above method embodiments. The output interface circuit is used to perform the transmitting operation in the above method embodiments.

[0354] The transceiver can be used for communication with other communication devices. For example, if communication device 600 is a terminal, the transceiver can be used to communicate with access network equipment or with another terminal. As another example, if communication device 600 is an access network device, the transceiver can be used to communicate with a terminal or with another access network device.

[0355] Optionally, the transceiver may include a receiver and / or a transmitter. The receiver is used to perform the receiving operation in the above method embodiments. The transmitter is used to perform the sending operation in the above method embodiments.

[0356] Optionally, the transceiver can be integrated with the processor 602 or exist independently and be coupled to the processor 602 through the interface circuit of the communication device 600. This application embodiment does not specifically limit this.

[0357] Processor 602 can be used to support communication device 600 in performing the processing actions in the above method embodiments. When communication device 600 is used to implement the above method embodiments, processor 602 can also be used to implement the functions of processing unit 502. Processor 602 can be a CPU, or other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. General-purpose processors can be microprocessors or any conventional processor. Processor 602 is used to perform processing-related operations in the above method embodiments, for example, to instruct operations other than receiving and sending operations in the above method embodiments.

[0358] In one embodiment, the communication device 600 is applied to the first device in the embodiment of this application shown in FIG3. The specific functions of the processor 602 in this embodiment are described below.

[0359] Processor 602 is configured to: transmit a reference signal via interface circuit 601; receive first information via interface circuit 601, the first information indicating at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix including the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; and receive second information via interface circuit 601, the second information indicating at least one stream combination, each stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain the precoding matrices corresponding to each subband respectively.

[0360] In another embodiment, the communication device 600 is applied to the second device in the embodiment of this application shown in FIG3. The specific functions of the processor 602 in this embodiment are described below.

[0361] Processor 602 is configured to: receive a reference signal via interface circuit 601; transmit first information via interface circuit 601, the first information indicating at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix including the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; and transmit second information via interface circuit 601, the second information indicating at least one stream combination, each stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain the precoding matrices corresponding to each subband respectively.

[0362] The specific functions of processor 602 can be found in the description of the communication methods provided in the above embodiments and examples of this application, as well as the specific functional description of communication device 500 in the embodiment of this application shown in Figure 5, which will not be repeated here.

[0363] Memory 603 is used to store program instructions and / or data. Specifically, program instructions may include program code, which includes computer operation instructions. Memory 603 may include RAM and may also include non-volatile memory, such as at least one disk storage device. Processor 602 executes the program instructions stored in memory 603 and uses the data stored in memory 603 to implement the above-mentioned functions, thereby realizing the communication method provided in the embodiments of this application. Memory 603 may be integrated with processor 602 or may be a memory outside the communication device.

[0364] It is understood that the memory 603 in Figure 6 of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be RAM, which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as 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 linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0365] This application also provides a communication device 700, which can be a terminal, a processor in the terminal, or a chip. The communication device 700 can be used to perform the operations performed by the first device in the above method embodiments.

[0366] When the communication device 700 is a terminal, Figure 7 shows a schematic diagram of the terminal's structure. As shown in Figure 7, the terminal includes a processor, a memory, and a transceiver. The memory can store computer program code, and the transceiver includes a transmitter 731, a receiver 732, radio frequency circuitry (not shown in the figure), an antenna 733, and input / output devices (not shown in the figure).

[0367] The processor is mainly used to process communication protocols and communication data; control terminals; execute software programs; and process data from software programs.

[0368] Memory is mainly used to store software programs and data.

[0369] Radio frequency (RF) circuits are mainly used for the conversion between baseband signals and RF signals, as well as for the processing of RF signals.

[0370] Antennas are primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves.

[0371] Input / output devices can include touchscreens, displays, or keyboards. They are primarily used to receive user input and output data to the user. It should be noted that some types of terminals may not have input / output devices.

[0372] When data needs to be transmitted, the processor performs baseband processing on the data to be transmitted and outputs a baseband signal to the radio frequency (RF) circuit. The RF circuit then processes the baseband signal and transmits it outwards as electromagnetic waves via an antenna. When data is sent to the terminal, the RF circuit receives the RF signal through the antenna. The RF circuit converts the RF signal back into a baseband signal and outputs it to the processor. The processor converts the baseband signal back into data and processes that data.

[0373] For ease of explanation, Figure 7 shows only one memory, processor, and transceiver. In actual terminal products, there may be one or more processors and one or more memories. Memory may also be called storage medium or storage device, etc. Memory may be set up independently of the processor or integrated with the processor; this application embodiment does not impose any limitations on this.

[0374] In the embodiments of this application, the antenna and radio frequency circuit with transceiver functions can be regarded as the interface unit of the terminal, and the processor with processing functions can be regarded as the processing unit of the terminal.

[0375] As shown in Figure 7, the terminal includes a processor 710, a memory 720, and a transceiver 730. The processor 710 may also be referred to as a processing board, processing module, or processing device. The transceiver 730 may also be referred to as an interface circuit, transceiver, or transceiver device. The processor 710 is used to execute the processing operations on the first device side in the above method embodiments. The transceiver 730 is used to execute the transmit and receive operations on the first device side in the above method embodiments.

[0376] Optionally, the device in transceiver 730 used for receiving functions can be considered a receiver, and the device in transceiver 730 used for transmitting functions can be considered a transmitter; that is, transceiver 730 includes a receiver 732 and a transmitter 731. A receiver may also be called a receiver module, a receiving circuit, etc. A transmitter may also be called a transmitter, a transmitting module, or a transmitting circuit, etc. The receiver is used to perform the receiving operation on the first device side in the above method embodiments. The transmitter is used to perform the transmitting operation on the first device side in the above method embodiments.

[0377] It should be understood that Figure 7 is merely an example and not a limitation, and the terminal may not depend on the structure shown in Figure 7.

[0378] When the communication device 700 is a chip, the chip includes a processor and a transceiver. The transceiver can be an input / output circuit or a communication interface. The processor can be a processing module integrated on the chip, a microprocessor, or an integrated circuit. In the above method embodiments, the transmitting operation of the first device can be understood as the chip's output, and the receiving operation of the first device in the above method embodiments can be understood as the chip's input.

[0379] The communication device 700 may also include a memory, which may be a memory built into the chip or an external memory.

[0380] This application also provides a communication device 800, which can be an access network device or a chip. The communication device 800 can be used to perform the operations performed by the second device in the above method embodiments.

[0381] When the communication device 800 is an access network device, such as a base station, Figure 8 shows a schematic diagram of the structure of an access network device. The access network device includes parts 810, 820, and 830.

[0382] The 810 section is mainly used for baseband processing and controlling access network equipment; the 810 section is usually the control center of the base station, which can be called a processor, and is used to control the access network equipment to perform the processing operations on the second device side in the above method embodiment.

[0383] The 820 section is primarily used to store computer program code and data.

[0384] The 830 section is primarily used for transmitting and receiving radio frequency (RF) signals, as well as converting RF signals to baseband signals. The 830 section is commonly referred to as a transceiver module, transceiver, transceiver circuit, interface circuit, or transceiver unit. The 830 section may include an antenna 833 and RF circuitry (not shown in the figure), where the RF circuitry is mainly used for RF processing. The 830 section can be used to perform the transmit and receive operations on the second device side in the above method embodiments.

[0385] Optionally, the device used to implement the receiving function in part 830 can be regarded as a receiver, and the device used to implement the transmitting function can be regarded as a transmitter; that is, part 830 includes receiver 832 and transmitter 831. The receiver can also be called a receiving module, receiver circuit, etc., and the transmitter can be called a transmitting module, transmitter, or transmitting circuit, etc. The receiver is used to perform the receiving operation on the second device side in the above method embodiments. The transmitter is used to perform the transmitting operation on the second device side in the above method embodiments.

[0386] Sections 810 and 820 may include one or more boards, each board may include one or more processors and one or more memories. The processor is used to read and execute programs in the memory to implement baseband processing functions and control access network devices. If multiple boards exist, they can be interconnected to enhance processing capabilities. As an optional implementation, multiple boards may share one or more processors, multiple boards may share one or more memories, or multiple boards may simultaneously share one or more processors.

[0387] It should be understood that Figure 8 is merely an example and not a limitation, and access network devices may not depend on the structure shown in Figure 8.

[0388] When the communication device 800 is a chip, the chip includes a transceiver and a processor. The transceiver can be an input / output circuit or a communication interface; the processor can be a processor integrated on the chip, a microprocessor, or an integrated circuit. In the above method embodiments, the transmitting operation of the second device can be understood as the chip's output, and the receiving operation of the second device in the above method embodiments can be understood as the chip's input.

[0389] The communication device 800 may also include a memory, which may be a memory built into the chip or an external memory.

[0390] Based on the above embodiments, this application also provides a computer program product including computer-executable instructions, which, when run, causes the methods provided in the above embodiments to be executed.

[0391] Based on the above embodiments, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a computer, causes the computer to perform the methods provided in the above embodiments.

[0392] The storage medium can be any available medium that a computer can access. For example, but not limited to, a computer-readable medium can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0393] Based on the above embodiments, this application also provides a chip for reading a computer program stored in a memory to implement the method provided in the above embodiments.

[0394] Based on the above embodiments, this application provides a chip system including a processor for supporting a computer device in implementing the functions involved in the devices in the above embodiments. In one possible design, the chip system further includes a memory for storing necessary programs and data of the computer device. The chip system may be composed of chips or may include chips and other discrete components.

[0395] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0396] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0397] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0398] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0399] In this application, the terms "system" and "network" are used interchangeably. "At least one item" refers to one or more items, and "more than one item" refers to two or more items. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. In the textual description of this application, the character " / " generally indicates that the objects before and after it are in an "or" relationship. For example, A / B can mean A or B, where A and B can be singular or plural.

[0400] Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that "first" and "second" are not necessarily different. Additionally, the numbering of steps in the various embodiments described in this application is only for distinguishing different steps and is not intended to limit the order of steps.

[0401] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0402] In this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of this application, unless otherwise specified or there is a logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships. The following descriptions of the embodiments of this application do not constitute a limitation on the scope of protection of this application.

[0403] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process does not imply 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 this application.

[0404] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0405] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, Applied to the first device, comprising: Send a reference signal; Receive first information, the first information being used to indicate at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix including the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; Receive second information, the second information being used to indicate at least one stream combination, each of the at least one stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrix corresponding to each of the subbands respectively.

2. The method as described in claim 1, characterized in that, Also includes: Receive first indication information, which is used to instruct the interpolation of the precoding matrix of a portion of the subbands in all the subbands.

3. The method as described in claim 1 or 2, characterized in that, Also includes: Receive second indication information, the second indication information being used to indicate at least one of the following: the at least one sub-band, or the number of sub-bands in the at least one sub-band.

4. The method according to any one of claims 1 to 3, characterized in that, Also includes: Receive third information, the third information being used to indicate one or more stream combinations, each of the one or more stream combinations comprising one or more streams, the one or more stream combinations being combinations of streams corresponding to the at least one precoding matrix.

5. A communication method, characterized in that, Applied to a second device, comprising: Receive reference signal; Send first information, the first information being used to indicate at least one precoding matrix, the at least one precoding matrix being determined based on the reference signal, the at least one precoding matrix comprising the precoding matrix of each subband in at least one subband, the at least one subband being a portion of all subbands occupied by the reference signal; Send a second message, the second message being used to indicate at least one stream combination, each of the at least one stream combination including at least one stream, the at least one precoding matrix being used to interpolate at the granularity of each of the at least one stream combination to obtain the precoding matrix corresponding to each of the subbands respectively.

6. The method as described in claim 5, characterized in that, Also includes: Send a first indication message, which is used to instruct the interpolation of the precoding matrix of a portion of the subbands in all the subbands.

7. The method as described in claim 5 or 6, characterized in that, Also includes: Send a second indication message, the second indication message being used to indicate at least one of the following: the at least one sub-band, or the number of sub-bands in the at least one sub-band.

8. The method according to any one of claims 5 to 7, characterized in that, Also includes: Send a third message, the third message being used to indicate one or more stream combinations, each of the one or more stream combinations comprising one or more streams, the one or more stream combinations being combinations of streams corresponding to the at least one precoding matrix.

9. The method as described in claim 4 or 8, characterized in that, The third information is used to indicate one or more stream combinations, including at least one of the following: The third information is used to indicate O, where O is the number of streams included in each of the one or more stream combinations, and O is a positive integer. The q-th stream combination in the one or more stream combinations includes the 1+(q-1)*O to the 0+(q-1)*O streams in the stream corresponding to the data transmission, and q is a positive integer. or The fourth stream combination is any one of the one or more stream combinations, and the third information includes the index of each stream in the fourth stream combination.

10. The method according to any one of claims 4, 8, and 9, characterized in that, The first flow combination is any flow combination among the at least one flow combination, and all flows of the first flow combination belong to one of the one or more flow combinations.

11. The method according to any one of claims 1 to 10, characterized in that, The number of flows included in different flow combinations in the at least one flow combination may be the same or different.

12. The method according to any one of claims 1 to 11, characterized in that, The second information is used to indicate at least one stream combination, including at least one of the following: The second information is used to indicate N, where N is the number of streams included in each of the at least one stream combination, and N is a positive integer. The m-th stream combination in the at least one stream combination includes the 1+(m-1)*N to N+(m-1)*N streams in the stream corresponding to the data transmission, where m is a positive integer; or The first stream combination is any one of the at least one stream combination, and the second information includes the index of each stream in the first stream combination.

13. The method according to any one of claims 1 to 12, characterized in that, The at least one stream combination includes a second stream combination, the first stream being any stream in the second stream combination, and the at least one precoding matrix is ​​used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands, including: The first and second precoding vectors are used to obtain the third precoding vector through interpolation; Wherein, the first precoding vector is the precoding vector corresponding to the first stream in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first sub-band among the at least one sub-band; the second precoding vector is the precoding vector corresponding to the first stream in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second sub-band among the at least one sub-band; the third precoding vector is the precoding vector corresponding to the first stream in the third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third sub-band, and the third sub-band is the sub-band other than the at least one sub-band among all the sub-bands.

14. The method according to any one of claims 1 to 13, characterized in that, The at least one stream combination includes a third stream combination, the third stream combination includes multiple streams, and the at least one precoding matrix is ​​used to interpolate at the granularity of each stream combination in the at least one stream combination to obtain the precoding matrices corresponding to each of the subbands, including: The first and second matrices are used to obtain the third matrix through interpolation; Wherein, the first matrix includes precoding vectors corresponding to the plurality of streams in the first precoding matrix, and the first precoding matrix is ​​the precoding matrix of the first sub-band among the at least one sub-band; the second matrix includes precoding vectors corresponding to the plurality of streams in the second precoding matrix, and the second precoding matrix is ​​the precoding matrix of the second sub-band among the at least one sub-band; the third matrix includes precoding vectors corresponding to the plurality of streams in the third precoding matrix, and the third precoding matrix is ​​the precoding matrix of the third sub-band, and the third sub-band is the sub-band other than the at least one sub-band among all the sub-bands.

15. A communication device, characterized in that, Includes a unit for performing the method as described in any one of claims 1-14.

16. A communication device, characterized in that, Includes a processor for executing computer programs or instructions that cause the apparatus to perform the method as described in any one of claims 1-14.

17. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions, which, when executed, implement the method as described in any one of claims 1-14.

18. A computer program product, characterized in that, The computer program product includes: computer program code, which, when the computer program code is run, implements the method as described in any one of claims 1-14.

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