Channel state information feedback method and communication apparatus

Abstract

The present application provides a channel state information feedback method and a communication apparatus, capable of reducing the feedback overhead of channel state information and being applied to a communication system. The method comprises: a first device receives a reference signal, and sends first indication information to a second device on the basis of the reference signal. The first indication information is determined on the basis of the reference signal, and the first indication information is used for indicating a plurality of first spatial domain basis vectors. The plurality of first spatial domain basis vectors are some or all of spatial domain basis vectors in first spatial domain bases. The first spatial domain bases comprise: spatial domain bases that undergo zero-padding extension of second spatial domain bases of which the dimensions are less than the number of antenna ports of the second device among a plurality of second spatial domain bases such that the dimensions are equal to the number of antenna ports of the second device, and spatial domain bases of which the dimensions are equal to the number of antenna ports of the second device among the plurality of second spatial domain bases. The plurality of second spatial domain bases comprise some of spatial domain bases among spatial domain bases corresponding to the number of antenna ports of the second device.

Description

Channel state information feedback method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 5, 2023, with application number 202311658068.4 and application name “Channel State Information Feedback Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a channel state information feedback method and a communication device. Background Art

[0003] For spatially non-stationary channels, there may be signal propagation paths, such as scattering paths and / or direct paths, that are visible to local antenna ports in the antenna array. In order to reduce energy leakage during signal transmission, some possible implementation schemes can construct a spatial basis corresponding to the channel, that is, a spatial codebook, based on the antenna array corresponding to the network device. In this case, the spatial basis corresponding to the channel includes the spatial basis corresponding to the transmitting antenna array, and the spatial basis corresponding to the subarray of the antenna array is padded with zeros and expanded to the spatial basis corresponding to the number of antenna ports of the transmitting antenna array. The spatial basis vector selected by the receiving end is selected from the spatial basis vectors of all spatial basis vectors corresponding to the channel. Since the number of spatial basis vectors corresponding to the channel is large, the feedback overhead of the information used to indicate the spatial basis vector selected by the receiving end is too large. Summary of the Invention

[0004] Embodiments of the present application provide a channel state information feedback method and a communication device, which can reduce the feedback overhead of the channel state information.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, a channel state information feedback method is provided. The channel state information feedback method includes: a first device receives a reference signal from a second device. The first device sends first indication information to the second device. The first indication information is determined based on the reference signal. The first indication information is used to indicate multiple first spatial basis vectors. The multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis. The first spatial basis includes: each second spatial basis in a plurality of second spatial basis bases whose dimension is less than the number of antenna ports of the second device is padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in a plurality of second spatial basis bases whose dimension is equal to the number of antenna ports of the second device. The multiple second spatial basis bases include some of the spatial basis bases in the spatial basis bases corresponding to the number of antenna ports of the second device.

[0007] Based on the method provided in the first aspect, the first device can receive a reference signal from the second device and send a first indication information determined according to the reference signal to the second device, and the multiple first spatial basis vectors indicated by the first information are part or all of the first spatial basis. Since the first spatial basis includes each second spatial basis in the multiple second spatial basis whose dimension is less than the number of antenna ports of the second device, padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and the spatial basis in the multiple second spatial basis whose dimension is equal to the number of antenna ports of the second device, that is, the number of spatial basis vectors in the first spatial basis is the same as the number of spatial basis vectors in the multiple second spatial basis, and the multiple second spatial basis includes some spatial basis in the spatial basis corresponding to the number of antenna ports of the second device. It can be seen that the number of spatial basis vectors in the first spatial basis is less than the number of spatial basis vectors in the spatial basis corresponding to the number of antenna ports of the second device, so that the feedback overhead can be reduced.

[0008] It should be understood that the first device may be a terminal, and the second device may be a network device. Alternatively, the first device may be a network device, and the second device may be a terminal.

[0009] In one possible implementation, multiple second spatial basis bases are determined based on first information. The first information includes: division information of the second device's antenna array, the number of antenna ports of the second device's antenna array in a first direction, the number of antenna ports of the second device's antenna array in a second direction, and angular domain sampling information. The first direction is perpendicular to the second direction. This allows for flexible configuration of the codebook's spatial basis, effectively reducing codebook space and feedback information.

[0010] In one possible implementation scheme, the division information of the antenna array of the second device is used to indicate: the division method of each level of antenna subarrays in the antenna array of the second device. The division method includes horizontal division or vertical division. Alternatively, the division information of the antenna array of the second device is used to indicate: the array number of the minimum antenna subarrays in an antenna array in the antenna array of the second device. Alternatively, the division information of the antenna array of the second device is used to indicate: the total number of antenna arrays in the antenna array of the second device. The number of antenna ports of the antenna arrays at the same level is the same. Among the multiple second spatial basis, each second spatial basis corresponds to an antenna array in the antenna array after the antenna array of the second device is divided, that is, each second spatial basis corresponds to an antenna array in the antenna array of each level of the second device. In this way, the spatial basis of the codebook can be flexibly configured and the indication overhead can be reduced by using as little indication information as possible to indicate the antenna array division method.

[0011] In one possible implementation, the first information further includes distance domain sampling information. In this way, spatial basis vectors can be set for different distances so that the spatial basis vectors match the distances, thereby further improving the accuracy of the spatial basis vectors.

[0012] In one possible implementation, the distance-domain sampling information includes one or more of the following: maximum sampling distance, minimum sampling distance, and sampling accuracy. This allows for flexible selection of spatial sampling accuracy based on actual scenarios, balancing channel distance-domain quantization accuracy with quantization channel storage and / or computational overhead.

[0013] In one possible implementation, the method provided in the first aspect may further include: the first device receiving second indication information from the second device. The second indication information is used to indicate the first information. In other words, the second device can indicate the first information. This, on the one hand, reduces the computing overhead of the first device, and on the other hand, allows the second device to centrally and rationally allocate communication resources.

[0014] In one possible implementation, the multiple second spatial basis bases include Q second spatial basis bases of different dimensions. The antenna ports corresponding to all second spatial basis bases of the same dimension include all antenna ports of the second device, and Q is a positive integer. Thus, the spatial basis bases included in the codebooks of different levels may include spatial basis bases corresponding to visible subarrays or antenna ports of all scattering paths.

[0015] In one possible implementation, the type of the spatial basis vector corresponding to each of the multiple second spatial basis bases is related to the equivalent aperture of the antenna subarray corresponding to the second spatial basis. This allows the antenna array to be matched to the type of the spatial basis vector, thereby reducing energy leakage during signal transmission and improving transmission performance.

[0016] In one possible implementation, if the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to a phase difference threshold, the second spatial basis is a spatial basis vector that includes angle information. If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, the second spatial basis is a spatial basis vector that includes both distance and angle information. In this way, a basis vector whose type matches the phase difference can be selected based on the phase difference between antenna ports in the antenna array, further improving the accuracy of the spatial basis vector.

[0017] In one possible implementation, the first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the index, phase, and amplitude of the multiple first spatial basis vectors. In this way, the channel can be accurately quantized by indicating the amplitude and phase information of the spatial basis vectors corresponding to different angles.

[0018] In one possible implementation, the first indication information is used to indicate the indexes of the plurality of first spatial basis vectors, including the first indication information being used to indicate the spatial angle corresponding to each of the plurality of first spatial basis vectors. In this way, spatial information in the channel angle domain can be accurately quantified.

[0019] In one possible implementation, the first indication information used to indicate the index of the plurality of first spatial basis vectors includes the first indication information used to indicate the spatial angle and distance corresponding to each of the plurality of first spatial basis vectors. In this way, spatial information in the channel range-angle domain can be accurately quantified.

[0020] In one possible implementation, the first indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis bases. In this way, the spatial basis vector can be indicated by the first indication information, reducing the processing complexity of the first device.

[0021] In one possible implementation, the second indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis. In this way, the first device can independently determine the type of the spatial basis vector in the second spatial basis, so that the type of the spatial basis vector in the second spatial basis better matches the actual channel.

[0022] In a second aspect, a channel state information feedback method is provided. The channel state information feedback method includes: a second device sends a reference signal to a first device. The second device receives first indication information from the first device. The first indication information is determined based on the reference signal, and the first indication information is used to indicate multiple first spatial basis vectors. Among them, the multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis. The first spatial basis includes: each second spatial basis in the multiple second spatial basis bases whose dimension is smaller than the number of antenna ports of the second device is padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in the multiple second spatial basis bases whose dimension is equal to the number of antenna ports of the second device. The multiple second spatial basis bases include some of the spatial basis bases in the spatial basis bases corresponding to the number of antenna ports of the second device.

[0023] In one possible implementation, multiple second spatial basis bases are determined based on first information, where the first information includes: division information of the antenna array of the second device, the number of antenna ports of the antenna array of the second device in a first direction, the number of antenna ports of the antenna array of the second device in a second direction, and angular domain sampling information. The first direction is perpendicular to the second direction.

[0024] In one possible implementation scheme, the division information of the antenna array of the second device is used to indicate: the division method of each level of antenna subarrays in the antenna array of the second device. The division method includes horizontal division or vertical division. Alternatively, the division information of the antenna array of the second device is used to indicate: the minimum number of antenna subarrays in an antenna array in the antenna array of the second device. Alternatively, the division information of the antenna array of the second device is used to indicate: the total number of antenna array levels in the antenna array of the second device. The number of antenna ports of the antenna arrays at the same level is the same. Among the multiple second spatial domain bases, each second spatial domain base corresponds to an antenna array in the antenna array after the antenna array of the second device is divided, that is, each second spatial domain base corresponds to an antenna array in the antenna arrays of each level of the second device.

[0025] In a possible implementation, the first information further includes: distance domain sampling information.

[0026] In a possible implementation, the distance domain sampling information includes one or more of the following: a maximum sampling distance, a minimum sampling distance, and a sampling accuracy.

[0027] In a possible implementation, the method provided in the second aspect may further include: the second device sending second indication information to the first device, wherein the second indication information is used to indicate the first information.

[0028] In one possible implementation, the multiple second spatial basis bases include Q second spatial basis bases of different dimensions, wherein the antenna ports corresponding to all second spatial basis bases of the same dimension include all antenna ports of the second device, and Q is a positive integer.

[0029] In a possible implementation, the type of the spatial basis vector corresponding to each second spatial basis of the multiple second spatial basis is related to the equivalent aperture in the antenna subarray corresponding to the second spatial basis.

[0030] In one possible implementation, if the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to a phase difference threshold, the second spatial basis is a spatial basis vector including angle information. If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, the second spatial basis is a spatial basis vector including distance information and angle information.

[0031] In a possible implementation, the first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the index, phase, and amplitude of the multiple first spatial basis vectors.

[0032] In a possible implementation, the first indication information is used to indicate the indexes of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle corresponding to each spatial basis vector in the multiple first spatial basis vectors.

[0033] In a possible implementation, the first indication information is used to indicate the index of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle and distance corresponding to each spatial basis vector in the multiple first spatial basis vectors.

[0034] In a possible implementation, the first indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis.

[0035] In a possible implementation, the second indication information is further used to indicate the type of the spatial basis vector in each second spatial basis in multiple second spatial basis.

[0036] In a possible implementation, the method provided in the second aspect may further include: the second device precoding the downlink data according to the first indication information.

[0037] In addition, the technical effects of the method described in the second aspect can refer to the technical effects of the method described in the first aspect, and will not be repeated here.

[0038] In a third aspect, a communication device is provided, which is configured to execute the channel state information feedback method according to any one of the implementations of the first and second aspects.

[0039] In the present application, the communication device described in the third aspect can be a terminal network device, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0040] It should be understood that the communication device described in the third aspect includes a module, unit, or means corresponding to the channel state information feedback method described in any one of the first and second aspects. The module, unit, or means can be implemented through hardware, software, or hardware executing the corresponding software implementation. The hardware or software includes one or more modules or units for performing the functions involved in the channel state information feedback method.

[0041] In a fourth aspect, a communication device is provided, including a processor configured to execute the channel state information feedback method according to any one of the possible implementations of the first and second aspects.

[0042] In one possible implementation, the communication device described in the fourth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fourth aspect to communicate with other communication devices.

[0043] In one possible implementation, the communication device described in the fourth aspect may further include a memory. The memory may be integrated with the processor or provided separately. The memory may be used to store computer programs and / or data related to the channel state information feedback method described in either the first aspect or the second aspect.

[0044] In the present application, the communication device described in the fourth aspect can be a terminal network device, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0045] In a fifth aspect, a communication device is provided. The communication device includes: a processor coupled to a memory, the processor configured to execute a computer program stored in the memory, so that the communication device performs the channel state information feedback method described in any possible implementation of the first and second aspects.

[0046] In one possible implementation, the communication device described in the fifth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fifth aspect to communicate with other communication devices.

[0047] In the present application, the communication device described in the fifth aspect can be a terminal network device, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0048] In the sixth aspect, a communication device is provided, comprising: a processor and a memory; the memory is used to store a computer program, and when the processor executes the computer program, the communication device executes the channel state information feedback method described in any one of the implementation methods of the first and second aspects.

[0049] In one possible implementation, the communication device described in the sixth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the sixth aspect to communicate with other communication devices.

[0050] In the present application, the communication device described in the sixth aspect can be a terminal network device, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0051] In the seventh aspect, a communication device is provided, comprising: a processor; the processor is used to couple with a memory, and after reading a computer program in the memory, execute the channel state information feedback method as described in any one of the implementation methods of the first aspect and the second aspect according to the computer program.

[0052] In one possible implementation, the communication device described in the seventh aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the seventh aspect to communicate with other communication devices.

[0053] In the present application, the communication device described in the seventh aspect can be a terminal network device, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0054] In an eighth aspect, a processor is provided, wherein the processor is configured to execute the channel state information feedback method described in any possible implementation of the first aspect and the second aspect.

[0055] In a ninth aspect, a communication system is provided, which includes one or more terminals and one or more network devices.

[0056] In the tenth aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are run on a computer, the computer is enabled to execute the channel state information feedback method described in any possible implementation of the first aspect and the second aspect.

[0057] In the eleventh aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed on a computer, enables the computer to execute the channel state information feedback method described in any one of the possible implementations of the first and second aspects.

[0058] In addition, the technical effects of the communication devices described in the third to eleventh aspects above can refer to the technical effects of the channel state information feedback methods described in the first and second aspects above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG1 is a schematic diagram of a CSI reporting process according to an embodiment of the present application;

[0060] FIG2 is a schematic diagram of the relationship between the scatterer and the antenna array provided in an embodiment of the present application;

[0061] FIG3 is a schematic diagram of a wavefront provided in an embodiment of the present application;

[0062] FIG4 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0063] FIG5 is a schematic diagram of a protocol architecture between a network device and a terminal according to an embodiment of the present application;

[0064] FIG6 is a schematic diagram of a flow chart of a channel state information feedback method provided in an embodiment of the present application;

[0065] FIG7 is a schematic diagram of antenna arrays of different levels provided in an embodiment of the present application;

[0066] FIG8 is a schematic diagram of elements of the spatial basis corresponding to each level of antenna array provided in an embodiment of the present application;

[0067] FIG9 is a schematic diagram of azimuth and elevation angles provided in an embodiment of the present application;

[0068] FIG10 is a first structural diagram of a communication device provided in an embodiment of the present application;

[0069] FIG11 is a second structural diagram of the communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0070] The technical terms and related technical solutions in this application will be described below in conjunction with the accompanying drawings.

[0071] In a communication system using multiple input multiple output (MIMO) technology, a transmitting device may precode data before transmitting. The transmitting device may precode the data based on channel state information (CSI) reported by a receiving device. For ease of understanding, the embodiments of this application are described with the transmitting device being a network device, such as an access network device, and the receiving device being a terminal, and further description will be omitted. It should be understood that in some possible implementations, the transmitting end may be a terminal and the receiving end may be a network device.

[0072] The following first introduces the CSI reporting process provided by the embodiment of the present application.

[0073] Please refer to Figure 1, which is a flowchart of CSI reporting provided by an embodiment of the present application. As shown in Figure 1, the CSI reporting process includes the following steps S101 to S104:

[0074] S101: A network device sends channel measurement configuration information to a terminal.

[0075] The channel measurement configuration information is used to indicate channel measurement and configuration parameters for the channel measurement, such as parameters for configuring time domain resources and frequency domain resources. For example, the channel measurement configuration information may indicate resources used to carry channel state information reference signals (CSI-RS), i.e., CSI-RS resources.

[0076] S102: The network device sends a CSI-RS to the terminal on the CSI-RS resource. Correspondingly, the terminal receives the CSI-RS from the network device on the CSI-RS resource.

[0077] In a communication system, such as a new radio (NR) system, a network device sends a CSI-RS on a CSI-RS resource for a terminal to detect a downlink channel, and the terminal receives the CSI-RS on a pre-configured CSI-RS resource to perform channel estimation.

[0078] S103: The terminal obtains CSI according to the CSI-RS.

[0079] The CSI carries information for indicating the spatial basis vector selected by the terminal from the spatial basis, that is, the codebook.

[0080] For the implementation principle of S103, reference may be made to the related method for obtaining CSI in the prior art, which will not be repeated here.

[0081] S104: The terminal reports the CSI to the network device.

[0082] In one possible implementation, when the antenna array is relatively small, the scattered path and / or direct path in the signal propagation path (referred to as the signal path) between the network device and the terminal are visible relative to all antenna ports of the network device. In other words, the visible area of ​​each propagation path includes the entire antenna array area. In other words, the channel between the network device and the terminal is a stationary channel. In this case, the spatial basis shown in S103 above is constructed for a spatially stationary channel.

[0083] However, in some communication systems with large antenna arrays, such as extremely large antenna array (ELAA) communication systems, the distribution of terminals and scatterers in the signal propagation environment, as well as the relative position relationship of the scatterers with respect to the antenna array of the network device, will cause the scattering path corresponding to some scatterers to be visible to local antenna ports in the antenna array (such as antenna ports corresponding to subarrays of the antenna array of the network device). In other words, the visible area of ​​some scatterers includes the area where some antenna ports in the antenna array are located, that is, the channel of the communication system exhibits non-stationary characteristics in the airspace, or in other words, the channel of the communication system is a non-stationary channel. For ease of understanding, the relationship between the visible area of ​​the antenna port and the scatterer in the ELAA communication system is illustrated below in conjunction with Figure 2. Taking a linear array as an example, as shown in Figure 2, the antenna array of a network device includes multiple antenna ports. There are four scatterers between the network device and the terminal. Scatterer 1's visible area includes visible areas 1 through 4, scatterer 2's visible area includes visible areas 1 and 2, scatterer 3's visible area includes visible area 3, and scatterer 4's visible area includes visible area 4. Each visible area includes some of the antenna ports in the antenna array. Therefore, scatterers 2 through 4 are visible only to some of the antenna ports.

[0084] For spatially non-stationary channels, assuming the existence of signal paths, such as scattering paths and / or visibility to local antenna ports in the antenna array, if a spatial basis constructed for spatially stationary channels is used, energy leakage will occur when sending signals.

[0085] In order to reduce energy leakage when sending signals, in some possible implementation schemes, the spatial basis corresponding to the channel, that is, the spatial codebook, can be constructed based on the antenna array corresponding to the network device. For example, the spatial basis (that is, the spatial codebook space) can be determined based on antenna arrays with different starting points and different dimensions in the transmitting antenna array, and the spatial basis vector can be selected from the spatial basis according to the actual channel state. In this case, the spatial basis corresponding to the channel includes the spatial basis corresponding to all antenna ports of the antenna array, and the spatial basis corresponding to the subarray of the antenna array is padded with zeros and expanded to the spatial basis corresponding to the number of antenna ports of the antenna array. The antenna array corresponding to the network device includes antenna arrays with different antenna port dimensions and different starting positions.

[0086] Taking the antenna array of a network device including 8 antenna ports, that is, a linear array of antenna port 0 to antenna port 7 as an example, the spatial basis corresponding to the channel includes all spatial basis whose dimensions are less than 8, the number of antenna ports of the network device, wherein different spatial basis correspond to different antenna arrays. The number of antenna ports corresponding to the antenna array, the antenna array, the antenna ports corresponding to the antenna array, the number of spatial basis corresponding to the antenna array, and the spatial basis corresponding to the antenna array are shown in Table 1 below. Among them, the antenna array corresponding to the spatial basis whose dimension is less than the number of antenna ports of the network device is a subarray of the antenna array of the second device. That is to say, antenna array 0 includes all antenna ports of the network device, antenna array 1 to antenna array 35 are all subarrays of antenna array 0, and antenna array 1 to antenna array 35 all include all antenna ports of the network device.

[0087] Table 1

[0088] From Table 1 above, we can see that the number of spatial bases corresponding to the channels is 8*1+7*2+6*3+5*4+4*5+3*6+2*7+1*8=100. When the antenna array is larger, the number of spatial bases in the spatial base corresponding to the channels is greater.

[0089] Thus, when a terminal selects a spatial basis vector, it must select from all spatial basis vectors corresponding to the channel. The information indicating the spatial basis vector selected by the terminal must indicate which of all spatial basis vectors corresponding to the channel the spatial basis vector represents. Because the number of spatial basis vectors corresponding to the channel is large, this leads to high feedback overhead for the information indicating the selected spatial basis vector.

[0090] Furthermore, in communication systems with smaller antenna arrays, signals sent from antenna ports at different locations on a network device have similar phase differences when they arrive at the terminal. Under the same carrier, the wavefronts of signals sent from antenna ports at different locations can satisfy the plane wave assumption. As shown in Figure 3(a), for a plane wave, the transmission paths of signals sent from antenna ports at different locations are parallel to each other. The transmission distance of signals sent from antenna ports at different locations is related to the angle between the signal's transmission path and the antenna array plane. Therefore, the phase change of the signal at the terminal can be represented by the angle between the signal's transmission path and the antenna array plane. In this case, the spatial basis vectors in the spatial basis can be discrete Fourier transform (DFT) basis vectors. Alternatively, the spatial basis is a DFT basis. In ELAA communication systems, due to the expansion of the physical aperture of the antenna (for example, increasing the number of antennas or changing the antenna arrangement, such as relocating or sparsely arranging antennas), the phase differences of signals sent from two adjacent antenna ports in the network device's antenna array when arriving at the terminal are different. Under the same carrier, the wavefront of the signal satisfies the spherical wavefront assumption. As shown in (b) of Figure 3, for spherical waves, the angles between the signals sent at different positions and the antenna array are different, and the transmission distances of the signals sent at different positions are also different. The signals at different positions need to be represented by the angles between the signal transmission path and the antenna array and the transmission distance.

[0091] In the plane wave scenario, the DFT basis (i.e., DFT codebook) used is designed for plane waves and does not take into account the differences in propagation distances and emission angles of signals sent from antenna ports at different locations. Therefore, if the DFT basis is applied to the spherical wave scenario, it will cause a mismatch between the DFT basis and the channel. In other words, the signal sent by the network device will not achieve the coherence effect in the plane wave scenario when it reaches the terminal.

[0092] It is understandable that in the above solution, the network device can be replaced by other sending ends, and the terminal can be replaced by other receiving ends.

[0093] The technical solution in this application will be described below with reference to the accompanying drawings.

[0094] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as wireless fidelity (WiFi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, 4th generation (4G) mobile communication systems, such as long term evolution (LTE) systems, world-wide interoperability for microwave access (WiMAX) communication systems, fifth generation (5G) mobile communication systems, such as new radio (NR) systems, and future communication systems, such as sixth generation (6G) mobile communication systems.

[0095] This application will present various aspects, embodiments, or features in the context of systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. Furthermore, combinations of these aspects may also be used.

[0096] Additionally, in the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as an "exemplary" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner.

[0097] First, in this application, "used to indicate" can include being used for direct indication and being used for indirect indication. When describing a certain "information" as being used to indicate A, it can include whether the information directly indicates A or indirectly indicates A, but it does not necessarily mean that the information contains A.

[0098] The information indicated by a message is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, where there is an association between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

[0099] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of the various indication methods can be referred to the prior art and will not be repeated herein. As can be seen from the above, for example, when it is necessary to indicate multiple information of the same type, there may be a situation where the indication methods for different information are different. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0100] The information to be indicated can be sent as a whole, or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in this application. Among them, the sending period and / or sending time of these sub-information can be predefined, for example, predefined according to the protocol, or configured by the transmitting device by sending configuration information to the receiving device. Among them, the configuration information can, for example, but not limited to, include one or a combination of at least two of radio resource control (RRC) signaling, medium access control (MAC) layer signaling and physical layer signaling. Among them, MAC layer signaling, for example, includes MAC control element (CE); physical (PHY) layer signaling, for example, includes downlink control information (DCI).

[0101] Second, in the embodiments shown below, the first, second, and various numerical numbers are only used for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0102] Third, “pre-set”, or “pre-defined”, or “pre-configured” can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including a terminal and a network device), or can be pre-specified in a protocol, and this application does not limit its specific implementation method. Among them, “saving” can mean saving in one or more memories. The one or more memories can be set separately, or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories can also be partially set separately, and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, and this application does not limit it.

[0103] Fourth, the “protocol” involved in the embodiments of the present application may refer to a standard protocol in the field of communications, for example, it may include 3GPP’s LTE protocol (such as technical specification (TS) 36, i.e., TS36 series technical specifications), NR protocol (such as TS38 series technical specifications) and related protocols used in future communication systems. This application does not limit this.

[0104] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0105] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0106] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail using the communication system shown in Figure 4 as an example. For example, Figure 4 is a schematic diagram of the architecture of a communication system applicable to the method provided in the embodiments of the present application.

[0107] As shown in FIG4 , the communication system includes network equipment and terminals.

[0108] For example, the network devices may include network devices 401a to 401c, and the terminals may include terminals 402a to 402f. The terminals may be connected to the network devices wirelessly, and the network may be connected to the core network (not shown in FIG4 ) via wired or wireless means.

[0109] Among them, network devices and terminal devices can interact with each other.

[0110] A terminal may be a terminal with transceiver functions, or may be a chip or chip system provided in the terminal. The terminal may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station (MS), mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal in the embodiments of the present application can be a mobile phone, a cellular phone, a smart phone, a tablet computer, a wireless data card, a personal digital assistant (PDA), a wireless modem, a handheld device (handset), a laptop computer, a machine type communication (MTC) terminal, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a smart home device (for example, a refrigerator, a television, an air conditioner, an electric meter, etc.), an intelligent robot, a robotic arm, a workshop equipment, a wireless terminal in unmanned driving, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a vehicle-mounted terminal, a roadside unit with terminal function, a roadside control unit (ROU), ... unit, RSU), etc., flying equipment (for example, intelligent robots, hot air balloons, drones, airplanes), etc. The terminal of the present application may also be an on-board module, on-board module, on-board component, on-board chip or on-board unit that is built into the vehicle as one or more components or units. The terminal may also be other devices with terminal functions. For example, the terminal may also be a device that serves as a terminal function in D2D communication. The embodiments of the present application do not limit the device form of the terminal. The device for realizing the function of the terminal may be a terminal; it may also be a device that can support the terminal to realize the function, such as a chip system. The device can be installed in the terminal or used in combination with the terminal. In the embodiments of the present application, the chip system may be composed of chips, or may include chips and other discrete devices.

[0111] The network device may be a device with wireless transceiver functions, or may be a chip or chip system provided in the device, located in the access network (AN) of the communication system, and used to provide access services to the terminal. For example, the network device may be referred to as a radio access network (RAN) device, and may specifically be a next-generation mobile communication system, such as a 6G access network device, such as a 6G base station. Alternatively, in the next-generation mobile communication system, the network device may also have other naming methods, all of which are covered within the scope of protection of the embodiments of this application, and this application does not impose any limitation on this. Alternatively, the network device may include 5G, such as a gNB in ​​a new radio (NR) system, or one or a group of antenna panels (including multiple antenna panels) of a base station in 5G, or a network node constituting a gNB, a transmission and reception point (TRP or TP), or a transmission measurement function (TMF), such as a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), a radio unit (RU), an RSU with base station functions, a wired access gateway, or a 5G core network element. Alternatively, the network device may include an access point (AP) in a wireless fidelity (WiFi) system, a wireless relay node, a wireless backhaul node, various types of macro base stations, micro base stations (also known as small cells), relay stations, access points, wearable devices, vehicle-mounted devices, and the like.

[0112] Among them, the CU and DU can be set separately, or can also be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU) or a remote radio head (RRH). It can be understood that the network device can be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the access network RAN, or the CU can be divided into a network device in the core network CN, which is not limited here. In different systems, CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, the CU can also be called O-CU (Open CU), the DU can also be called O-DU, the CU-CP can also be called O-CU-CP, the CU-UP can also be called O-CU-UP, and the RU can also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. In the embodiment of the present application, the form of the network device is not limited. The device for implementing the function of the network device can be a network device; it can also be a device that can support the network device to implement the function, such as a chip system. The device can be installed in the network device or used in combination with the network device.

[0113] As shown in Figure 5 , the network device includes an RRC signaling interaction module (RRC in Figure 5 ), a MAC signaling interaction module (MAC in Figure 5 ), and a PHY signaling and data interaction module (PHY in Figure 5 ). The terminal also includes an RRC signaling interaction module, a MAC signaling interaction module, and a PHY signaling and data interaction module.

[0114] The network device and the terminal can exchange RRC signaling through the RRC signaling interaction module. The network device and the terminal can exchange media access control element (MAC CE) signaling through the MAC signaling interaction module. The network device and the terminal can exchange one or more of the following through the PHY interaction module: uplink control signaling, downlink control signaling (such as DCI), uplink data, and downlink data.

[0115] It should be noted that the channel state information feedback method provided in the embodiment of the present application can be applied between the nodes shown in Figure 4. For specific implementation, please refer to the following method embodiment, which will not be repeated here.

[0116] It should be noted that the solutions in the embodiments of the present application can also be applied to other communication systems, and the corresponding names can also be replaced by the names of corresponding functions in other communication systems.

[0117] It should be understood that FIG4 is only a simplified schematic diagram for ease of understanding, and the communication system may also include other network devices and / or other terminals, which are not shown in FIG4 .

[0118] Based on the communication system provided in Figure 4, an embodiment of the present application provides a channel state information feedback method. The channel state information feedback method includes: a first device receives a reference signal from a second device, and sends a first indication information generated according to the reference signal to the second device. The first indication information indicates a plurality of first spatial basis vectors, and the plurality of first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis. And the first spatial basis includes a part of the spatial basis corresponding to the antenna port of the second device, which is padded with zeros and expanded to a spatial basis with the same dimension as the antenna port of the second device. In this way, the number of spatial basis vectors included in the first spatial basis can be reduced, thereby reducing the feedback overhead.

[0119] The channel state information feedback method provided in the embodiment of the present application will be described in detail below with reference to FIG. 6 to FIG. 8 .

[0120] For example, Figure 6 is a flow chart of a channel state information feedback method according to an embodiment of the present application. The channel state information feedback method may be applicable to the communication between the two devices shown in Figure 4 .

[0121] As shown in FIG6 , the channel state information feedback method includes the following steps:

[0122] S601: A second device sends a reference signal to a first device. Correspondingly, the first device receives the reference signal from the second device.

[0123] The first device is a device that needs to receive data, and the second device is a device that needs to send data. The first device may be a terminal or a network device in the communication system provided in FIG4 , and the second device may be a terminal or a network device in the communication system provided in FIG4 . For example, in a downlink transmission scenario, the first device may be a terminal, and the second device may be a network device. For another example, in an uplink transmission scenario, the first device may be a network device, and the second device may be a terminal. For the implementation of the terminal and network device, please refer to the relevant introduction in the communication system provided in FIG4 , and will not be repeated here.

[0124] In a possible implementation, if the first device is a terminal and the second device is a network device, the reference signal in S601 may be a CSI-RS. It is understood that the reference signal may also be other possible reference signals, which will not be described in detail here.

[0125] For the implementation principle of S601, please refer to the relevant introduction in S102, which will not be repeated here.

[0126] S602: The first device determines first indication information according to a reference signal.

[0127] That is, the first indication information is determined according to the reference signal.

[0128] The first indication information is used to indicate multiple first spatial basis vectors. The multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis. The first spatial basis includes: each second spatial basis in the multiple second spatial basis whose dimension is smaller than the number of antenna ports of the second device is padded with zero and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in the multiple second spatial basis whose dimension is equal to the number of antenna ports of the second device. The multiple second spatial basis includes some of the spatial basis in the spatial basis corresponding to the number of antenna ports of the second device.

[0129] It should be understood that a spatial basis (such as the first spatial basis or the second spatial basis) may include one or more spatial basis vectors.

[0130] The spatial basis corresponding to the number of antenna ports of the second device includes: all spatial basis corresponding to the antenna arrays of different dimensions and different starting positions of the second device, that is, all antenna arrays corresponding to the second device. Among them, the antenna arrays of different dimensions and different starting positions of the second device include: the antenna array formed by arranging all antenna elements corresponding to all antenna ports of the second device, and all sub-arrays of the antenna array formed by arranging all antenna elements corresponding to all antenna ports of the second device. Taking the antenna array of the second device as a linear array, and the number of antenna ports of the second device as 8, such as antenna port 0 to antenna port 7 as an example, combined with the above Table 1, the antenna arrays of different dimensions and different starting positions of the second device include antenna array 0 to antenna array 35. The spatial basis corresponding to the number of antenna ports of the second device includes spatial basis 0 to spatial basis 35.

[0131] The multiple second spatial basis bases are partial spatial basis bases in the spatial basis bases corresponding to the number of antenna ports of the second device. The antenna array corresponding to each second spatial basis base is one of all antenna arrays corresponding to the second device. Each second spatial basis base in the multiple second spatial basis bases is a spatial basis base in the spatial basis bases corresponding to the number of antenna ports of the second device. For example, the spatial basis base corresponding to the number of antenna ports of the second device includes spatial basis bases 0 to 35. The second spatial basis base may be one of spatial basis bases 0 to 35, and the multiple second spatial basis bases may be multiple spatial basis bases from 0 to 35. For example, the multiple second spatial basis bases may include spatial basis base 0, 10, 14, 21, 22, 26, and 27. It is understood that the multiple second spatial basis bases are used for example only. In actual implementation, the multiple second spatial basis bases may include any portion of the spatial basis bases corresponding to the number of antenna ports of the second device, and this description is omitted.

[0132] It should be understood that in the second spatial basis, the number of spatial basis vectors and the number of elements in the spatial basis vectors may be the same as the number of antenna ports in the antenna array corresponding to the second spatial basis.

[0133] In the embodiment of the present application, the antenna ports of the second device include 8 antenna ports for example only. In actual implementation, the antenna ports of the second device can be 128, or 256 or more, which will not be repeated here.

[0134] In a possible implementation, the multiple second spatial basis bases include Q second spatial basis bases of different dimensions, where Q is a positive integer.

[0135] It will be understood that in the embodiments of the present application, the antenna arrays corresponding to the second spatial basis of different dimensions in the Q different-dimensional second spatial basis have different levels. That is, the antenna arrays corresponding to all second spatial basis in the multiple second spatial basis may include antenna arrays of multiple different levels. In other words, each second spatial basis of different dimensions corresponds to a first-level antenna array. Antenna arrays of different levels may have different numbers of rows or columns of antenna ports. Thus, the spatial basis included in the codebooks of different levels may include spatial basis corresponding to visible subarrays or antenna ports of all scattering paths.

[0136] Among them, the antenna ports corresponding to all second spatial basis of the same dimension in the Q different dimensional second spatial basis include all antenna ports of the second device. As shown in Figure 7, the following example uses the second device's antenna ports including antenna port 0 to antenna port 7, and the antenna array formed by antenna ports 0 to antenna port 7 is an 8*1 linear array. Assuming that the antenna array of the second device includes a primary antenna array, a secondary antenna array, and a tertiary antenna array, the primary antenna array includes antenna port 0 to antenna port 7. The first secondary antenna array includes antenna port 0 to antenna port 3, and the second secondary antenna array includes antenna port 4 to antenna port 7. The first tertiary antenna array includes antenna port 0 and antenna port 1, the second tertiary antenna array includes antenna port 2 and antenna port 3, the third tertiary antenna array includes antenna port 4 and antenna port 5, and the fourth tertiary antenna array includes antenna port 6 and antenna port 7. It can be seen that all antenna arrays corresponding to the second spatial basis with the same dimension are obtained by dividing all antenna ports of the second device, that is, by dividing the antenna array composed of all antenna elements of the first device.

[0137] It should be understood that the antenna port corresponding to a spatial basis refers to the antenna port in the antenna array corresponding to the spatial basis.

[0138] In one possible implementation, multiple second spatial bases are determined based on the first information. If the second device's antenna array is a planar array, the first information may include: division information of the second device's antenna array, the number of antenna ports of the second device's antenna array in a first direction, the number of antenna ports of the second device's antenna array in a second direction, and angular domain sampling information. The first direction is perpendicular to the second direction. This allows for flexible configuration of the codebook's spatial base, effectively reducing codebook space and feedback information.

[0139] In some possible implementations, if the antenna array has the same number of antenna ports in different directions, then in this case, the first information may include the division information of the antenna array of the second device, the number of antenna ports of the antenna array in one arrangement direction, and the angle domain sampling information. When the antenna array of the second device is distributed in both horizontal and vertical directions, the first direction may be the horizontal direction, and the second direction may be the vertical direction. Alternatively, the first direction may be the vertical direction, and the second direction may be the horizontal direction. Here, the first direction and the second direction are used for example only. In actual implementation, the first direction and the second direction may also be other possible directions.

[0140] When the antenna array of the second device is a linear array, the first information may include: division information of the antenna array of the second device, the number of antenna ports of the antenna array of the second device in the first direction, and angle domain sampling information.

[0141] The division information of the antenna array of the second device is information that can be used to determine the dimensions of the antenna port corresponding to each second spatial basis, or, in other words, the division information of the antenna array of the second device can be used to indicate the division method of the antenna array of the second device.

[0142] For ease of understanding, the division information of the antenna array of the second device is respectively described below in combination with Cases 1 to 3.

[0143] In case 1, the division information of the antenna array of the second device is used to indicate: a division method of each level of antenna subarray in the antenna array of the second device, wherein the division method includes horizontal division or vertical division.

[0144] Optionally, the division information of the antenna array of the second device may include a correspondence between different levels of antenna subarrays of the second device and the division method. For example, if the antenna array of the second device is divided into three levels of antenna arrays, the division information of the antenna array of the second device may include the correspondence shown in Table 2 below.

[0145] Table 2

[0146] The following example uses an antenna array with 8 rows and 16 columns. Assuming the antenna array division method shown in Table 2, the primary antenna array is an 8-row, 16-column antenna array. The resulting secondary antenna arrays are 4*16 antenna arrays (two in total), and the resulting tertiary antenna arrays are 4*8 antenna arrays (four in total). The first secondary antenna array includes antenna ports from rows 1 to 4 and columns 1 to 16, and the second secondary antenna array includes antenna ports from rows 5 to 8 and columns 1 to 16. The first tertiary antenna array includes antenna ports from rows 1 to 4 and columns 1 to 8. The second tertiary antenna array includes antenna ports from rows 1 to 4 and columns 1 to 8. The third tertiary antenna array includes antenna ports from rows 5 to 8 and columns 1 to 8. The fourth tertiary antenna array includes antenna ports from rows 5 to 8 and columns 9 to 16.

[0147] It is understandable that the correspondence between the number of antenna array levels and the division method shown in Table 2 is only for example. In actual implementation, there may be other correspondences between the number of antenna array levels and the division method, which will not be repeated here.

[0148] Case 2: the division information of the antenna array of the second device is used to indicate: in the antenna array of the second device, the minimum number of antenna sub-arrays in one antenna array.

[0149] It can be understood that in case 2, the division method of the antenna array of the second device can be agreed upon through a protocol. For example, taking a linear array as an example, assuming that the antenna array corresponding to the second device is an 8*1 linear array, including antenna port 0 to antenna port 7, and the minimum number of antenna subarrays in an antenna array is 2, then the primary antenna array can be an 8*1 linear array; the secondary antenna array can include two subarrays, namely, a subarray including antenna port 0 to antenna port 3, and a subarray including antenna port 4 to antenna port 7; the secondary antenna array can include four antenna ports, namely, a subarray including antenna port 0 and antenna port 1, a subarray including antenna port 2 and antenna port 3, a subarray including antenna port 4 and antenna port 5, and a subarray including antenna port 6 and antenna port 7.

[0150] Case 3: the division information of the antenna array of the second device is used to indicate: the total number of antenna array levels in the antenna array of the second device.

[0151] Among them, among the multiple second spatial basis, each second spatial basis corresponds to an antenna array in the antenna array after the antenna array of the second device is divided, that is, each second spatial basis corresponds to an antenna array in each level of antenna array of the second device.

[0152] In a possible implementation, the division method of each level of antenna array in Case 3 can be agreed upon through a protocol.

[0153] Based on cases 1 to 3, the antenna array division mode can be indicated by using as little indication information as possible, thereby flexibly configuring the spatial basis of the codebook and reducing indication overhead.

[0154] The antenna arrays at the same level have the same number of antenna ports.

[0155] In an embodiment of the present application, the second device can determine each level of antenna arrays based on the first information, and determine a second spatial basis based on each antenna array in each level of antenna arrays, thereby obtaining multiple second spatial basis. For the multiple second spatial basis, the spatial basis with a dimension less than the number of antenna ports of the second device is padded with zeros and expanded to a dimension equal to the number of antenna ports of the second device. In this way, based on the spatial basis with a dimension equal to the number of antenna ports of the second device in the multiple spatial basis, and the second spatial basis in the multiple second spatial basis is padded with zeros and expanded to a spatial basis with a dimension equal to the number of antenna ports of the second device, multiple first spatial basis can be obtained.

[0156] It should be understood that zero-padding expansion refers to adding "0" elements to positions in the second spatial basis vector corresponding to the antenna ports of the second device where no elements exist. Taking the three-level antenna array shown in Figure 8 as an example, as shown in Figure 8, for the first-level antenna array, there are non-zero elements at the positions corresponding to each antenna port, so zero-padding expansion is not required. For the first secondary antenna array, since its corresponding second spatial basis is determined based on the 0th to 3rd antenna ports, only elements corresponding to the 0th to 3rd antenna ports exist. Therefore, for the positions corresponding to the 0th to 3rd antenna ports, "0" elements can be added to expand, thereby obtaining a spatial basis in which each spatial basis includes 8 elements after zero-padding expansion. Similarly, the second spatial basis vectors corresponding to the second secondary antenna array, the first tertiary antenna array, and the fourth tertiary antenna array can be zero-padding expanded, which will not be repeated here. It can be understood that zero-padding expansion is relative to all antenna ports corresponding to the antenna array.

[0157] For ease of understanding, the first spatial basis is further explained below with reference to specific formulas.

[0158] Assume that the antenna arrays corresponding to the multiple second spatial bases are L levels in total, and the antenna array of level l includes K l antenna arrays, the kth antenna array in the lth level l The second spatial basis corresponding to the antenna array may include M l Spatial bases are 1,…,m l ,…,M l Among them, l, L, K l 、k l 、M l and m l are all positive integers, 1≤l≤L, 1≤k l ≤K l , 1≤m l ≤M l .

[0159] Then, the multiple second spatial domain bases corresponding to the l-th level antenna array after zero-filling expansion can be expressed by the following formula (1):

[0160] It can be understood that when l is greater than 1, It is zero-padded and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device.

[0161] The first spatial basis can be expressed by the following formula (2): W = [W1, ..., W l ,...,W L ]; (2)

[0162] In one possible implementation, the type of the spatial basis vector corresponding to each of the multiple second spatial basis bases is related to the equivalent aperture of the antenna subarray corresponding to the second spatial basis. In other words, the type of the spatial basis vector corresponding to each of the multiple second spatial basis bases is related to the propagation mode of the signal on the antenna array corresponding to the second spatial basis, where the signal propagation mode may include near-field propagation or far-field propagation.

[0163] In a possible implementation, the first indication information may also be used to indicate the type of the spatial basis vector in each of the multiple second spatial basis. That is, the second device indicates the type of the spatial basis vector in each of the second spatial basis.

[0164] In another possible design, the first device may independently determine the type of the spatial basis vector in each of the multiple second spatial basis.

[0165] The type of spatial basis vector may include spatial basis vectors of angle information. For example, in a scenario where the antenna array is for far-field transmission, the spatial basis vectors in the second spatial basis corresponding to the antenna array may be DFT basis vectors. Alternatively, the type of spatial basis vector may include spatial basis vectors of distance information and angle information. For example, in a scenario where the antenna array is for near-field transmission, the spatial basis vectors in the second spatial basis corresponding to the antenna array may be a near-field polar sampling basis.

[0166] Angle information refers to information used to indicate the angle of the signal path relative to different antenna ports. Each element in the channel matrix describes the signal attenuation amplitude and phase change corresponding to a pair of transmitters and receivers. If channel normalization is considered, only the phase change is described. The quantization of the channel matrix is ​​based on different basis vectors and specific angle information to determine a complex vector (the amplitude and phase of the complex vector represent the attenuation amplitude and phase change of the signal, respectively) to approximately describe the channel. In other words, each antenna port in the spatially stationary subarray has an angle corresponding to the received and transmitted signal in one direction or the angle of the received and transmitted signal in several directions. Based on this angle and the spacing between the antenna elements, the phase difference of the received and / or transmitted signal at each antenna port can be calculated, so that the channel matrix can be quantitatively restored.

[0167] In one possible design solution, near-field propagation or far-field propagation may be determined based on a phase difference between antenna ports in an antenna array.

[0168] In a possible implementation, if the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to a phase difference threshold, the second spatial basis is a spatial basis vector including angle information.

[0169] If the phase difference between the antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, the second spatial basis is a spatial basis vector including distance information and angle information.

[0170] Distance information refers to the physical distance between the signal transmission location and the signal reception location, which indicates the signal path. In near-field scenarios, the phase difference between antenna ports is also affected by both distance and angle.

[0171] In some possible design solutions, the signal propagation mode may also be related to the carrier wavelength, the signal propagation distance, and the size of the antenna array (e.g., the distance between the two antenna ports that are farthest apart in the antenna array). For example, the signal propagation mode can be determined according to the following formula (3).

[0172] Where r is the distance the signal propagates, D is the size of the antenna array, and λ is the wavelength of the carrier.

[0173] If r is greater than or equal to the distance threshold, the signal sent by the antenna array is far-field propagation; if r is less than the distance threshold, the signal sent by the antenna array is near-field propagation. It should be understood that the distance threshold can be determined based on the actual propagation distance of the signal and the wavelength of the carrier. Combined with formula (3), it can be seen that when the wavelength of the carrier is the same, the larger the area of ​​the antenna array, the greater the phase difference of the signals sent from different positions of the antenna array when they arrive at the first device, and the wavefront of the signal is closer to a spherical wave. The smaller the area of ​​the antenna array, the smaller the phase difference of the signals sent from different positions of the antenna array when they arrive at the first device, and the closer it is to a plane wave. Therefore, when the area of ​​the antenna array is greater than the area threshold, the second spatial basis is a spatial basis vector including angle information. When the area of ​​the antenna array is less than or equal to the area threshold, the second spatial basis is a spatial basis vector including distance information and angle information. Among them, the area threshold can be determined according to the actual scenario and will not be repeated here.

[0174] The spatial basis vector may also be called the spatial basis vector or other possible names, which will not be repeated here.

[0175] The following describes the first spatial basis in far-field transmission by taking the antenna array of the second device as a linear array and a planar array.

[0176] If the antenna array of the second device is a linear array and the antenna array is divided into three levels, that is, L = 3, then the second spatial basis (first-level codebook) corresponding to the first-level antenna array can be expressed by the following formula (4). In this case, the dimension of the spatial basis vector in the second spatial basis corresponding to the first-level antenna array is the same as the number of antenna ports of the second device: W1 = W N,DFT ; (4)

[0177] Among them, W1 is the second spatial basis corresponding to the first-level antenna array, W N,DFT is the DFT basis with dimension N*N, W N,DFT The matrix includes N DFT basis vectors of length N. N is the number of antenna ports of the second device.

[0178] The second spatial basis corresponding to each antenna array in the secondary antenna array is Right now By performing zero-filling expansion on the second spatial basis corresponding to each antenna array in the secondary antenna array, the spatial basis W2 after zero-filling expansion of the second spatial basis corresponding to each of the two secondary antenna arrays can be obtained, that is, the secondary codebook, which can be expressed by the following formula (5):

[0179] in, Indicates length The spatial basis composed of the DFT basis vectors, express The transpose of Indicates the dimension The zero matrix of .

[0180] Similarly, the spatial basis W3 corresponding to the second spatial basis of each of the four three-level antenna arrays after zero-filling expansion can be obtained, that is, the three-level codebook can be expressed by the following formula (6):

[0181] in, Indicates length The spatial basis composed of the DFT basis vectors, express The transpose of Indicates the dimension The zero matrix of Indicates the dimension The zero matrix of Indicates the dimension The zero matrix of .

[0182] It should be understood that the first spatial basis includes all spatial basis vectors in the first-level codebook to the third-level codebook.

[0183] The antenna array of the second device is a planar array, such as N v *N h In the scenario of the array, it is assumed that the antenna array is divided into three levels, where the dimension of the first-level antenna array is N v *N h , the dimension of the secondary antenna array is The dimensions of the three-level antenna array are

[0184] Assume that the sampling distance in each direction of the l-level antenna array is S, or in other words, then the sampling distance of the s-th distance sampling point satisfies the following formula (7):

[0185] Among them, r s is the distance of the sth sampling point in the l-level antenna array, s=0,1,2,…,S, S is the total number of sampling points of the l-level antenna array in one direction, r s,min is the minimum distance corresponding to S sampling points, r s,max is the maximum distance corresponding to S sampling points.

[0186] Then, the first spatial basis W can satisfy the relationship shown in the following formula (8):

[0187] in, is the n′th antenna array of the lth level l Azimuth, mth l The spatial basis vectors corresponding to the elevation angles are padded with zeros to expand to the same dimension as the number of antenna ports of the terminal, 1≤n′ l ≤N′,1≤m l ≤M, M and N' are both positive integers, The relationship shown in the following formula (9) is satisfied:

[0188] in, represents the nth ' of the l-level antenna array l Azimuth mth l Pitch angle The distance r from the sth sampling point s The corresponding spatial basis vector.

[0189] The following description is given with reference to the antenna array shown in FIG9 .

[0190] Assume that the antenna array is as shown in Figure 9, and the pitch angle corresponding to the antenna array to the i-th spatial basis vector is θ i , the azimuth angle from the antenna array to the i-th spatial basis vector is φ i , then the spatial basis vector of the channel corresponding to the signal path between the second device and the first device passing through the i-th scatterer is The following relationships shown in formulas (10) to (12) can be satisfied:

[0191] in, represents the Hadamard product, w Dis the basis vector in the distance domain, w A is the basis vector in the angle domain, i is the index of the basis in the spatial domain, 0 < i ≤ M * N′ * S, i is a positive integer, d h is the horizontal element spacing, d v is the vertical element spacing, r i represents the sampling distance corresponding to the i-th basis vector in the spatial domain, λ is the wavelength, n v represents the n v th horizontal antenna port, n h represents the n h th vertical antenna element, N v is the number of antenna ports in the horizontal direction, N h is the number of antenna ports in the vertical direction.

[0192] When the value of r i tends to ∞, w D [[ID=2 / 7]]becomes [1, 1, …, 1] T At this time At this time, is the basis vector in the spatial domain of the far field. That is to say, the basis vector in the spatial domain of the far field spatial basis is In this case, 0 < i ≤ M * N′.

[0193] Similarly, the spatial basis corresponding to the secondary antenna array can be obtained; zero-padding is performed on the positions of the non-selected sub-arrays in the spatial basis corresponding to the secondary antenna array, that is, the dimension of the spatial basis corresponding to the secondary antenna array is zero-padded and extended to the same as the number of antenna ports of the second device, and the basis after zero-padding and extension for each antenna array in the secondary antenna array can be obtained.

[0194] Similarly, the spatial basis corresponding to the tertiary antenna array can be obtained; zero-padding is performed on the positions of the non-selected sub-arrays in the spatial basis corresponding to the tertiary antenna array, that is, the dimension of the spatial basis corresponding to the tertiary antenna array is zero-padded and extended to the same as the number of antenna ports of the second device, and the basis after zero-padding and extension for each antenna array in the tertiary antenna array can be obtained.

[0195] is the azimuth angle, such as the angle between the projection of the signal and the antenna column on the horizontal plane. is the elevation angle, such as the angle between the projection of the signal and the antenna array in the vertical direction.

[0196] If both the secondary antenna array and the tertiary antenna array satisfy near-field transmission, then, the secondary codebook can refer to the principle shown in formulas (10) and (12) above, and the tertiary codebook can refer to the principle shown in formulas (10) and (12) above.

[0197] The angle domain sampling information may be used to indicate the direction of the beam and may include a quantized number of angles. Furthermore, the angle domain sampling information may include information indicating whether oversampling is required. If the angle domain sampling information indicates that oversampling is required, the angle domain sampling information may also include the number of angle domain oversamplings.

[0198] In a possible implementation, the first information further includes: distance domain sampling information.

[0199] In a possible implementation, the distance domain sampling information includes one or more of the following: a maximum sampling distance, a minimum sampling distance, and a sampling accuracy.

[0200] In this way, the spatial domain sampling accuracy can be flexibly selected according to the actual scenario, balancing the channel distance domain quantization accuracy and the quantization channel storage and / or computation overhead.

[0201] It can be understood that in the embodiment of the present application, determining the type of spatial basis vector based on the phase difference between antenna ports in the antenna array is only for example. In actual implementation, other possible methods can also be used to determine the type of spatial basis vector.

[0202] The first spatial basis composed of multiple first spatial basis vectors can also be called a codebook or a codebook space. The number of first spatial basis vectors in the multiple first spatial basis vectors is the size of the codebook space of the solution provided in the embodiment of the present application.

[0203] The multiple first spatial basis vectors, that is, at least some of the spatial basis vectors in the first spatial basis, are spatial basis vectors selected by the first device from the first spatial basis according to the measurement result of the reference signal, such as CSI-RS.

[0204] In one possible design scheme, multiple first spatial basis vectors may include spatial basis vectors corresponding to antenna arrays of each dimension, that is, spatial basis vectors in the spatial basis corresponding to the number of antenna ports of each dimension are padded with zeros and expanded to the same number of antenna ports as the second device.

[0205] In a possible implementation, the first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the indexes of multiple first spatial basis vectors, that is, the first indication information is used to indicate the index of each first spatial basis vector.

[0206] Optionally, the first indication information may also be used to indicate the phase and amplitude of multiple first spatial basis vectors, that is, the first indication information may also be used to indicate the phase and amplitude of each first spatial basis vector. In this way, the channel can be accurately quantized by indicating the amplitude and phase information of the spatial basis vectors corresponding to different angles.

[0207] In one possible implementation, the first indication information is used to indicate the indexes of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle corresponding to each first spatial basis vector in the multiple first spatial basis vectors. The spatial angle corresponding to the first spatial basis vector is the direction of the beam corresponding to the first spatial basis vector. In this way, spatial information in the channel angle domain can be accurately quantified.

[0208] In one possible design, the spatial angle corresponding to each first spatial basis vector can be represented by a spatial angle index. It is understood that representing the spatial angle using the spatial angle index is merely an example. In actual implementation, the spatial angle can also be represented by other possible methods, which are not further described here.

[0209] In one possible implementation, the first indication information is used to indicate the index of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle and distance corresponding to each first spatial basis vector in the multiple first spatial basis vectors. In this embodiment of the present application, the distance corresponding to the spatial basis vector refers to the distance parameter corresponding to the first spatial basis vector.

[0210] In one possible design, the distance corresponding to the spatial basis vector can be represented by a distance index. It is understood that the distance represented by the distance index is only for example. In actual implementation, the distance can also be represented by other possible methods, which will not be repeated here.

[0211] It should be understood that the scheme for determining the type of spatial basis vector in the embodiment of the present application is only for example. In actual implementation, other possible methods can also be used to determine the type of spatial basis, which will not be repeated here.

[0212] In S602, the second device may measure and obtain a channel state according to the received reference signal, and select a plurality of first spatial basis according to the channel state, thereby obtaining the first indication information.

[0213] S603: The first device sends first indication information to the second device. Correspondingly, the second device receives the first indication information from the first device.

[0214] The first indication information may be carried in RRC signaling or MAC CE, or may be carried on a physical uplink control channel (PUCCH).

[0215] In addition, the method provided in FIG. 6 may also have the following design solutions.

[0216] In one possible implementation, the method provided in the first aspect may further include: the second device sending second indication information to the first device. Correspondingly, the first device receiving the second indication information from the second device, wherein the second indication information is used to indicate the first information.

[0217] That is, the first information can be indicated by the second device, so that, on the one hand, the computing overhead of the first device can be saved, and on the other hand, the second device can reasonably allocate communication resources in a centralized manner.

[0218] In a possible design solution, the first information may be agreed upon by a protocol, or may be pre-stored in the second device.

[0219] In one possible implementation, the second indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis bases. For example, if the first indication information does not indicate the type of the spatial basis vector in each of the multiple second spatial basis bases, the second indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis bases.

[0220] In a possible implementation, the method provided in the second aspect may further include: the second device precoding the downlink data according to the first indication information.

[0221] The second device may first determine a precoding vector according to the first indication information, and then precode the downlink data according to the precoding vector. The following example illustrates how the second device determines the precoding vector.

[0222] In a possible design, it is assumed that in the first indication information, the basis vector of the reported level l codebook is b l , with an amplitude of a l , phase is c l , then the precoding vector used by the second device to send downlink data to the first device satisfies the relationship shown in the following formula (13):

[0223] The following further illustrates the above formula (21) with the help of the three-level codebook. It is assumed that the multiple first spatial bases selected by the second device include the spatial base and The energy selection coefficients corresponding to each first spatial basis are: ρ 1,1 ,ρ 2,1 ,ρ 3,2 and ρ 3,3 , that is, the first indication information indicates that: the multiple first spatial bases include the spatial base and The energy selection coefficients corresponding to each first spatial basis are: ρ1,1 ,ρ 2,1 ,ρ 3,2 and ρ 3,3 , then the precoding vector corresponding to the transmit beam of the second device can be expressed as shown in the following formula (14):

[0224] in, It is the spatial basis with index I1 corresponding to the first antenna array of the first level antenna array, that is, the spatial basis with index I1 in W1. It is the spatial basis with index I2 corresponding to the first antenna array of the second-level antenna array, that is, the spatial basis with index I2 in W2. It is the spatial basis with index I3 corresponding to the second antenna array of the third-level antenna array, that is, the spatial basis with index I3 in W3. It is the spatial basis with index I4 corresponding to the third antenna array of the third-level antenna array, that is, the spatial basis with index I4 in W3. 1,1 yes The corresponding beam combining coefficient, ρ 2,1 yes The corresponding beam combining coefficient, ρ 3,2 yes The corresponding beam combining coefficient, ρ 3,3 yes In this case, the first indication information indicates index I1, index I2, index I3 and index I4, and ρ 1,1 , ρ 2,1 , ρ 3,2 and ρ 3,3 .

[0225] It should be understood that I1, I2, I3, and I4 can be index identifiers or numerical values. If I1, I2, I3, and I4 are all numerical values, then any two of I1, I2, I3, and I4 can be continuous or discontinuous, and this embodiment of the present application does not limit this. Regarding the principle of precoding downlink data, reference can be made to the implementation principle of precoding in the existing technology, which will not be repeated here.

[0226] In one possible design, the method provided in FIG6 may further include: the second device sending precoded downlink data to the first device. Correspondingly, the first device receives the downlink data from the second device.

[0227] Based on the method provided in FIG6 , the first device can receive a reference signal from the second device and send first indication information determined based on the reference signal to the second device, where the multiple first spatial basis vectors indicated by the first information are part or all of the first spatial basis. Since the first spatial basis includes each second spatial basis in the multiple second spatial basis whose dimension is less than the number of antenna ports of the second device, padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and the spatial basis in the multiple second spatial basis whose dimension is equal to the number of antenna ports of the second device, that is, the number of spatial basis vectors in the first spatial basis is the same as the number of spatial basis vectors in the multiple second spatial basis, and the multiple second spatial basis includes some spatial basis vectors in the spatial basis corresponding to the number of antenna ports of the second device, it can be seen that the number of spatial basis vectors in the first spatial basis is less than the number of spatial basis vectors in the spatial basis corresponding to the number of antenna ports of the second device, thereby reducing the feedback overhead.

[0228] It should be understood that the first device in the method provided in Figure 6 may be a terminal, and the second device may be a network device. In some possible scenarios, the first device may also be a network device, and the second device may be a terminal.

[0229] The channel state information feedback method provided by the embodiment of the present application is described in detail above with reference to Figures 6 to 9. The communication device for executing the channel state information feedback method provided by the embodiment of the present application is described in detail below with reference to Figures 10 and 11.

[0230] For example, Figure 10 is a structural diagram of a communication device according to an embodiment of the present application. As shown in Figure 10 , the communication device 1000 includes a processing module 1001 and a transceiver module 1002. For ease of illustration, Figure 10 only shows the main components of the communication device 1000.

[0231] In some embodiments, the communication apparatus 1000 may be applicable to the communication system shown in FIG. 4 , and perform the function of the first device in the channel state information feedback method shown in FIG. 6 .

[0232] The transceiver module 1002 is configured to receive a reference signal from a second device.

[0233] The processing module 1001 is configured to determine first indication information according to a reference signal.

[0234] The first indication information is used to indicate multiple first spatial basis vectors. The multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis. The first spatial basis includes: each second spatial basis in the multiple second spatial basis has a dimension less than the number of antenna ports of the communication device 1000, padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the communication device 1000, and a spatial basis in the multiple second spatial basis has a dimension equal to the number of antenna ports of the communication device 1000. The multiple second spatial basis includes some of the spatial basis corresponding to the number of antenna ports of the communication device 1000.

[0235] The transceiver module 1002 is further configured to send first indication information to the second device.

[0236] In one possible implementation, multiple second spatial basis bases are determined based on first information, where the first information includes: division information of the antenna array of the second device, the number of antenna ports of the antenna array of the second device in a first direction, the number of antenna ports of the antenna array of the second device in a second direction, and angular domain sampling information. The first direction is perpendicular to the second direction.

[0237] In one possible implementation, the division information of the antenna array of the second device is used to indicate: a division method of each level of antenna subarrays in the antenna array of the second device. The division method includes horizontal division or vertical division. Alternatively, the division information of the antenna array of the second device is used to indicate: a minimum number of antenna subarrays in an antenna array in the antenna array of the second device. Alternatively, the division information of the antenna array of the second device is used to indicate: a total number of antenna array levels in the antenna array of the second device. Antenna arrays of the same level have the same number of antenna ports. Among the multiple second spatial basis, each second spatial basis corresponds to an antenna array in the antenna array after the antenna array of the second device is divided.

[0238] In a possible implementation, the first information may further include: distance domain sampling information.

[0239] In a possible implementation, the distance domain sampling information includes one or more of the following: a maximum sampling distance, a minimum sampling distance, and a sampling accuracy.

[0240] In a possible implementation, the transceiver module 1002 is further configured to receive second indication information from a second device, wherein the second indication information is used to indicate the first information.

[0241] In one possible implementation, the multiple second spatial basis bases include Q second spatial basis bases of different dimensions, wherein the antenna ports corresponding to all second spatial basis bases of the same dimension include all antenna ports of the second device, and Q is a positive integer.

[0242] In a possible implementation, the type of the spatial basis vector corresponding to each second spatial basis of the multiple second spatial basis is related to the equivalent aperture in the antenna subarray corresponding to the second spatial basis.

[0243] In one possible implementation, if the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to a phase difference threshold, the second spatial basis is a spatial basis vector including angle information. If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, the second spatial basis is a spatial basis vector including distance information and angle information.

[0244] In a possible implementation, the first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the index, phase, and amplitude of the multiple first spatial basis vectors.

[0245] In a possible implementation, the first indication information is used to indicate the indexes of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle corresponding to each spatial basis vector in the multiple first spatial basis vectors.

[0246] In a possible implementation, the first indication information is used to indicate the index of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle and distance corresponding to each spatial basis vector in the multiple first spatial basis vectors.

[0247] In a possible implementation, the first indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis.

[0248] In a possible implementation, the second indication information is further used to indicate the type of the spatial basis vector in each second spatial basis in multiple second spatial basis.

[0249] Optionally, the transceiver module 1002 may include a receiving module and a sending module (not shown in FIG10 ). The transceiver module 1002 is used to implement the sending function and the receiving function of the communication device 1000 .

[0250] Optionally, the communication apparatus 1000 may further include a storage module (not shown in FIG10 ) storing a program or instruction. When the processing module 1001 executes the program or instruction, the communication apparatus 1000 may perform the functions of the first device in the channel state information feedback method shown in FIG6 .

[0251] It should be understood that the processing module 1001 involved in the communication device 1000 can be implemented by a processor or a processor-related circuit component, which can be a processor or a processing unit; the transceiver module 1002 can be implemented by a transceiver or a transceiver-related circuit component, which can be a transceiver or a transceiver unit.

[0252] It should be noted that the communication device 1000 can be a terminal or a network device, or a chip (system) or other parts or components that can be set in a terminal or a network device, or a device that includes a terminal or a network device. This application does not limit this.

[0253] In addition, the technical effects of the communication device 1000 can refer to the technical effects of the channel state information feedback method shown in Figure 6, which will not be repeated here.

[0254] In some other embodiments, the communication apparatus 1000 may be applicable to the communication system shown in FIG. 4 , and perform the function of the second device in the channel state information feedback method shown in FIG. 6 .

[0255] The processing module 1001 is configured to generate a reference signal, and the transceiver module 1002 is configured to send the reference signal to the first device.

[0256] The transceiver module 1002 is also used to receive first indication information from the first device. The first indication information is determined based on the reference signal. The first indication information is used to indicate multiple first spatial basis. Among them, each spatial basis in the multiple first spatial basis is a spatial basis in the first spatial basis. The first spatial basis includes: each second spatial basis in the multiple second spatial basis with a dimension less than the number of antenna ports of the second device is padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in the multiple second spatial basis with a dimension equal to the number of antenna ports of the second device. The multiple second spatial basis includes some spatial basis in the spatial basis corresponding to the number of antenna ports of the second device.

[0257] In one possible implementation, multiple second spatial basis bases are determined based on first information, where the first information includes: division information of the antenna array of the communication device 1000, the number of antenna ports of the antenna array of the communication device 1000 in a first direction, the number of antenna ports of the antenna array of the communication device 1000 in a second direction, and angle domain sampling information. The first direction is perpendicular to the second direction.

[0258] In one possible implementation, the division information of the antenna array of the communication device 1000 is used to indicate the division method of each level of antenna subarrays in the antenna array of the communication device 1000. The division method includes horizontal division or vertical division. Alternatively, the division information of the antenna array of the communication device 1000 is used to indicate the minimum number of antenna subarrays in an antenna array of the communication device 1000. Alternatively, the division information of the antenna array of the communication device 1000 is used to indicate the total number of antenna array levels in the antenna array of the communication device 1000. Antenna arrays of the same level have the same number of antenna ports. Each of the multiple second spatial basis bases corresponds to an antenna array in the antenna array after the antenna array of the communication device 1000 is divided.

[0259] In a possible implementation, the first information further includes: distance domain sampling information.

[0260] In a possible implementation, the distance domain sampling information includes one or more of the following: a maximum sampling distance, a minimum sampling distance, and a sampling accuracy.

[0261] In a possible implementation, the transceiver module 1002 is further configured to send second indication information to the first device, wherein the second indication information is used to indicate the first information.

[0262] In one possible implementation, the multiple second spatial basis bases include Q second spatial basis bases of different dimensions, wherein the antenna ports corresponding to all second spatial basis bases of the same dimension include all antenna ports of the communication device 1000 .

[0263] In a possible implementation, the type of the spatial domain basis corresponding to each second spatial domain basis of the multiple second spatial domain basis is related to the equivalent aperture in the antenna subarray corresponding to the second spatial domain basis.

[0264] In one possible implementation, if the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to a phase difference threshold, the second spatial basis is a spatial basis vector including angle information. If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, the second spatial basis is a spatial basis vector including distance information and angle information.

[0265] In a possible implementation, the first indication information is used to indicate multiple first spatial bases, including: the first indication information is used to indicate the index, phase and amplitude of the multiple first spatial bases.

[0266] In a possible implementation, the first indication information is used to indicate the indexes of multiple first spatial bases, including: the first indication information is used to indicate the spatial angle corresponding to each spatial base in the multiple first spatial bases.

[0267] In a possible implementation, the first indication information is used to indicate the indexes of the multiple first spatial bases, including: the first indication information is used to indicate the spatial angle and distance corresponding to each spatial base in the multiple first spatial bases.

[0268] In a possible implementation, the first indication information is further used to indicate the type of the spatial basis vector in each of the multiple second spatial basis.

[0269] In a possible implementation, the second indication information is further used to indicate the type of the spatial basis vector in each second spatial basis in multiple second spatial basis.

[0270] In a possible implementation, the processing module 1001 is further configured to precode the downlink data according to the first indication information.

[0271] Optionally, the transceiver module 1002 may include a receiving module and a sending module (not shown in FIG10 ). The transceiver module 1002 is used to implement the sending function and the receiving function of the communication device 1000 .

[0272] Optionally, the communication apparatus 1000 may further include a storage module (not shown in FIG10 ) storing a program or instruction. When the processing module 1001 executes the program or instruction, the communication apparatus 1000 may perform the function of the second device in the channel state information feedback method shown in FIG6 .

[0273] It should be understood that the processing module 1001 involved in the communication device 1000 can be implemented by a processor or a processor-related circuit component, which can be a processor or a processing unit; the transceiver module 1002 can be implemented by a transceiver or a transceiver-related circuit component, which can be a transceiver or a transceiver unit.

[0274] It should be noted that the communication device 1000 can be a terminal or a network device, or a chip (system) or other parts or components that can be set in a terminal or a network device, or a device that includes a terminal or a network device. This application does not limit this.

[0275] In addition, the technical effects of the communication device 1000 can refer to the technical effects of the channel state information feedback method shown in Figure 6, which will not be repeated here.

[0276] For example, FIG11 is a second structural diagram of a communication device provided in an embodiment of the present application. The communication device may be a terminal device or a network device, or a chip (system) or other component or assembly that can be provided in a terminal or a network device. As shown in FIG11 , the communication device 1100 may include a processor 1101. Optionally, the communication device 1100 may further include a memory 1102 and / or a transceiver 1103. The processor 1101 is coupled to the memory 1102 and the transceiver 1103, such as by a communication bus.

[0277] The following is a detailed introduction to the various components of the communication device 1100 with reference to FIG11 :

[0278] The processor 1101 is the control center of the communication device 1100 and can be a single processor or a collective term for multiple processing elements. For example, the processor 1101 can be one or more central processing units (CPUs), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more digital signal processors (DSPs) or one or more field programmable gate arrays (FPGAs).

[0279] Optionally, the processor 1101 may execute various functions of the communication device 1100 by running or executing a software program stored in the memory 1102 and calling data stored in the memory 1102 .

[0280] In a specific implementation, as an embodiment, the processor 1101 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG11 .

[0281] In a specific implementation, as an embodiment, the communication device 1100 may also include multiple processors, such as the processor 1101 and the processor 1104 shown in FIG11 . Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0282] Among them, the memory 1102 is used to store the software program for executing the solution of this application, and the execution is controlled by the processor 1101. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0283] Alternatively, the memory 1102 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 1102 may be integrated with the processor 1101 or exist independently and be coupled to the processor 1101 via an interface circuit (not shown in FIG. 11 ) of the communication device 1100, which is not specifically limited in this embodiment of the present application.

[0284] Transceiver 1103 is used for communication with other communication devices. For example, if communication device 1100 is a terminal, transceiver 1103 can be used to communicate with a network device or another terminal. For another example, if communication device 1100 is a network device, transceiver 1103 can be used to communicate with a terminal or another network device.

[0285] Optionally, the transceiver 1103 may include a receiver and a transmitter (not shown separately in FIG11 ), wherein the receiver is used to implement a receiving function, and the transmitter is used to implement a transmitting function.

[0286] Optionally, the transceiver 1103 may be integrated with the processor 1101 or exist independently and be coupled to the processor 1101 through an interface circuit (not shown in FIG. 11 ) of the communication device 1100 . This embodiment of the present application does not specifically limit this.

[0287] It should be noted that the structure of the communication device 1100 shown in FIG11 does not constitute a limitation on the communication device. An actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0288] In addition, the technical effects of the communication device 1100 can refer to the technical effects of the channel state information feedback method described in the above method embodiment, and will not be repeated here.

[0289] It should be understood that the processor in the embodiments of the present application may be a CPU, but may also be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0290] It should also be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a ROM, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an EEPROM, or a flash memory. The volatile memory can be a 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 link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0291] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (such as infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0292] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0293] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0294] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0295] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0296] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0297] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0298] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0299] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0300] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0301] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A channel state information feedback method, characterized in that: The method comprises: The first device receives a reference signal from the second device; The first device sends first indication information to the second device; the first indication information is determined based on the reference signal; the first indication information is used to indicate multiple first spatial basis vectors; wherein the multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis; the first spatial basis includes: each second spatial basis in the multiple second spatial basis with a dimension smaller than the number of antenna ports of the second device is padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in the multiple second spatial basis with a dimension equal to the number of antenna ports of the second device; the multiple second spatial basis includes some spatial basis in the spatial basis corresponding to the number of antenna ports of the second device.

2. The method according to claim 1, characterized in that: The multiple second spatial domain bases are determined based on first information, wherein the first information includes: division information of the antenna array of the second device, the number of antenna ports of the antenna array of the second device in the first direction, the number of antenna ports of the antenna array of the second device in the second direction, and angle domain sampling information; the first direction is perpendicular to the second direction.

3. The method according to claim 2, characterized in that The division information of the antenna array of the second device is used to indicate: a division method of each level of antenna subarray in the antenna array of the second device; wherein the division method includes horizontal division or vertical division; or, The division information of the antenna array of the second device is used to indicate: the minimum number of antenna subarrays in one antenna array in the antenna array of the second device; or, The division information of the antenna array of the second device is used to indicate: the total number of levels of antenna arrays in the antenna array of the second device; wherein the number of antenna ports of antenna arrays at the same level is the same; Among the multiple second spatial domain bases, each second spatial domain base corresponds to an antenna array among the antenna arrays after the antenna array of the second device is divided.

4. The method according to claim 2 or 3, characterized in that: The first information also includes: distance domain sampling information.

5. The method according to claim 4, characterized in that The distance domain sampling information includes one or more of the following: maximum sampling distance, minimum sampling distance and sampling accuracy.

6. The method according to any one of claims 2 to 5, characterized in that: The method further comprises: The first device receives second indication information from the second device; wherein the second indication information is used to indicate the first information.

7. The method according to any one of claims 1 to 6, characterized in that The multiple second spatial domain bases include Q second spatial domain bases of different dimensions; wherein the antenna ports corresponding to all second spatial domain bases of the same dimension include all antenna ports of the second device, and Q is a positive integer.

8. The method according to any one of claims 1 to 7, characterized in that The type of the spatial basis vector corresponding to each second spatial basis of the multiple second spatial basis is related to the equivalent aperture of the antenna subarray corresponding to the second spatial basis.

9. The method according to claim 8, characterized in that If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to the phase difference threshold, then the second spatial basis is a spatial basis vector including angle information; If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than the phase difference threshold, then the second spatial basis is a spatial basis vector including distance information and angle information.

10. The method according to any one of claims 1 to 9, characterized in that The first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the index, phase and amplitude of the multiple first spatial basis vectors.

11. The method according to claim 10, characterized in that The first indication information is used to indicate the index of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle corresponding to each spatial basis vector in the multiple first spatial basis vectors.

12. The method according to claim 10, characterized in that The first indication information is used to indicate the index of the multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle and distance corresponding to each spatial basis vector in the multiple first spatial basis vectors.

13. The method according to any one of claims 1 to 12, characterized in that The first indication information is also used to indicate the type of the spatial basis vector in each second spatial basis among the multiple second spatial basis.

14. The method according to claim 6, characterized in that The second indication information is also used to indicate the type of the spatial basis vector in each second spatial basis among the multiple second spatial basis.

15. A channel state information feedback method, characterized in that: The method comprises: The second device sends a reference signal to the first device; The second device receives first indication information from the first device; the first indication information is determined based on the reference signal; the first indication information is used to indicate multiple first spatial basis vectors; wherein the multiple first spatial basis vectors are part or all of the spatial basis vectors in the first spatial basis; the first spatial basis includes: each second spatial basis in the multiple second spatial basis with a dimension less than the number of antenna ports of the second device is padded with zeros and expanded to a spatial basis with the same dimension as the number of antenna ports of the second device, and a spatial basis in the multiple second spatial basis with a dimension equal to the number of antenna ports of the second device; the multiple second spatial basis includes some of the spatial basis in the spatial basis corresponding to the number of antenna ports of the second device.

16. The method according to claim 15, characterized in that The multiple second spatial domain bases are determined based on first information, wherein the first information includes: division information of the antenna array of the second device, the number of antenna ports of the antenna array of the second device in the first direction, the number of antenna ports of the antenna array of the second device in the second direction, and angle domain sampling information; the first direction is perpendicular to the second direction.

17. The method according to claim 16, characterized in that The division information of the antenna array of the second device is used to indicate: a division method of each level of antenna subarray in the antenna array of the second device; wherein the division method includes horizontal division or vertical division; or, The division information of the antenna array of the second device is used to indicate: the minimum number of antenna subarrays in one antenna array in the antenna array of the second device; or, The division information of the antenna array of the second device is used to indicate: the total number of levels of antenna arrays in the antenna array of the second device; wherein the number of antenna ports of antenna arrays at the same level is the same; Among the multiple second spatial domain bases, each second spatial domain base corresponds to an antenna array among the antenna arrays after the antenna array of the second device is divided.

18. The method according to claim 16 or 17, characterized in that The first information also includes: distance domain sampling information.

19. The method according to claim 18, characterized in that The distance domain sampling information includes one or more of the following: maximum sampling distance, minimum sampling distance and sampling accuracy.

20. The method according to any one of claims 16 to 19, characterized in that The method further comprises: The second device sends second indication information to the first device; wherein the second indication information is used to indicate the first information.

21. The method according to any one of claims 15 to 20, characterized in that The multiple second spatial domain bases include Q second spatial domain bases of different dimensions; wherein the antenna ports corresponding to all second spatial domain bases of the same dimension include all antenna ports of the second device, and Q is a positive integer.

22. The method according to any one of claims 15 to 21, characterized in that The type of the spatial basis vector corresponding to each second spatial basis of the multiple second spatial basis is related to the antenna port in the antenna array corresponding to the second spatial basis.

23. The method according to claim 22, characterized in that If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is less than or equal to the phase difference threshold, then the second spatial basis is a spatial basis vector including angle information; If the phase difference between antenna ports in the antenna array corresponding to the second spatial basis is greater than a phase difference threshold, the second spatial basis is a spatial basis vector including distance information and angle information.

24. The method according to any one of claims 15 to 23, characterized in that The first indication information is used to indicate multiple first spatial basis vectors, including: the first indication information is used to indicate the index, phase and amplitude of the multiple first spatial basis vectors.

25. The method according to claim 24, characterized in that The first indication information is used to indicate the index of multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle corresponding to each spatial basis vector in the multiple first spatial basis vectors.

26. The method according to claim 24, characterized in that The first indication information is used to indicate the index of the multiple first spatial basis vectors, including: the first indication information is used to indicate the spatial angle and distance corresponding to each spatial basis vector in the multiple first spatial basis vectors.

27. The method according to any one of claims 16 to 26, characterized in that The first indication information is also used to indicate the type of the spatial basis vector in each second spatial basis among the multiple second spatial basis.

28. The method according to claim 20, characterized in that The second indication information is also used to indicate the type of the spatial basis vector in each second spatial basis among the multiple second spatial basis.

29. The method according to any one of claims 15 to 28, characterized in that The method further comprises: The second device precodes the downlink data according to the first indication information.

30. A communication device, characterized in that: The communication device is used to execute the channel state information feedback method according to any one of claims 1 to 14, or the communication device is used to execute the channel state information feedback method according to any one of claims 15 to 29.

31. A communication device, characterized in that: include: Processor and memory; The memory is used to store computer instructions. When the processor executes the instructions, the communication device executes the channel state information feedback method as described in any one of claims 1-14, or executes the channel state information feedback method as described in any one of claims 15-29.

32. A communication device, characterized in that: include: processor and interface circuit; wherein, The interface circuit is used to receive code instructions and transmit them to the processor; The processor is used to run the code instructions to execute the channel state information feedback method according to any one of claims 1-14, or to execute the channel state information feedback method according to any one of claims 15-29.

33. A communication device, characterized in that: The communication device includes a processor and a transceiver, the transceiver is used to exchange information between the communication device and other communication devices, and the processor executes program instructions to execute the channel state information feedback method described in any one of claims 1-14, or executes the channel state information feedback method described in any one of claims 15-29.

34. The communication device according to any one of claims 30 to 33, characterized in that: The communication device is a chip.

35. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a computer program or instructions, and when the computer program or instructions are executed on a computer, the computer executes the channel state information feedback method as described in any one of claims 1 to 14, or executes the channel state information feedback method as described in any one of claims 15 to 29.

36. A computer program product, characterized in that The computer program product includes: a computer program or instructions, which, when executed on a computer, enables the computer to execute the channel state information feedback method as described in any one of claims 1 to 14, or to execute the channel state information feedback method as described in any one of claims 15 to 29.

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