Channel state information reporting method and related product

Abstract

A channel state information reporting method and a related product. The method comprises: receiving a first reference signal; and sending first information on the basis of the received first reference signal, wherein the first information comprises indication information of at least one first spatial domain base vector corresponding to a first precoding matrix, the first precoding matrix is obtained on the basis of the at least one first spatial domain base vector and at least one second spatial domain base vector, and the at least one second spatial domain base vector is obtained on the basis of n second precoding matrices. A terminal device determines some of the spatial domain base vectors on the basis of a historical measurement result, and only needs to report the indication information of the remaining spatial domain base vectors corresponding to the precoding matrices, so that a network device can perform recovering to obtain the precoding matrices on the basis of the indication information of the spatial domain base vectors reported by the terminal device and some of the spatial domain base vectors determined by the terminal device on the basis of the historical measurement result, thereby saving the reporting overhead of the channel state information.

Description

Channel state information reporting method and related products

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 26, 2023, with application number 202311812897.3 and invention name “Channel State Information Reporting Method and Related Products”, 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 (CSI) reporting method and related products. Background Art

[0003] In frequency division duplex (FDD) mode, the terminal device is required to report the CSI of the downlink channel to the network device. The CSI includes the precoding matrix indicator (PMI). The network device determines the precoding of the data transmitted to the terminal device based on the PMI reported by the terminal device.

[0004] PMI reporting is determined and reported based on a set of codebooks. The design of the FDD CSI codebook is the fifth generation (5 th generation, 5G) and future communication systems is a fundamental and important issue.

[0005] The PMI reporting method supported by the existing protocol is real-time reporting for each measurement. Considering the high-precision codebook, the reporting overhead is relatively large.

[0006] In view of this, how to reduce the CSI reporting overhead is an urgent problem to be solved. Summary of the Invention

[0007] The present application provides a channel state information reporting method and related products to reduce the reporting overhead of CSI.

[0008] In a first aspect, a channel state information acquisition method is provided, which can be implemented by a terminal device, or a chip or circuit used for the terminal device.

[0009] The method includes: receiving a first reference signal; and sending first information based on the first reference signal, wherein the first information includes indication information of at least one first spatial basis vector corresponding to a first precoding matrix, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and at least one second spatial basis vector, and the at least one second spatial basis vector is obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1.

[0010] In this aspect, the terminal device determines part of the spatial basis vectors based on historical measurement results, and only needs to report the indication information of the remaining part of the spatial basis vectors corresponding to the precoding matrix, so that the network device can recover the precoding matrix based on the indication information of the spatial basis vectors reported by the terminal device and the part of the spatial basis vectors determined by the historical measurement results; taking into account the slowly changing characteristics of the channel in the spatial domain, the part of the spatial basis vectors determined according to the historical measurement results can better reflect the spatial characteristics of the precoding matrix to be reported, and only a small number of additional spatial basis vectors need to be indicated to correct the spatial beam direction, thereby saving the reporting overhead of the channel state information.

[0011] The at least one first spatial basis vector and the at least one second spatial basis vector are both used to characterize the spatial characteristics of the first precoding matrix. The at least one first spatial basis vector can be understood as being used to correct the spatial beam direction of the at least one second spatial basis vector, so that the set of spatial basis vectors consisting of the at least one first spatial basis vector and the at least one second spatial basis vector can better characterize the spatial characteristics of the first precoding matrix with as few spatial basis vectors as possible.

[0012] In a possible implementation, before receiving the first reference signal, the method further includes: receiving a second reference signal n times; and sending indication information of the n second precoding matrices respectively based on the second reference signals received n times.

[0013] In this implementation, the indication information of the n second precoding matrices is used to obtain at least one second spatial basis vector. The n second precoding matrices are precoding matrices obtained through historical measurement and reporting relative to the first precoding matrix.

[0014] In another possible implementation, the at least one second spatial basis vector is obtained based on precoding vectors corresponding to the x transmission layers of the first frequency domain unit in the n second precoding matrices.

[0015] In this implementation, since the spatial domain characteristics change slowly, the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices can be extracted to obtain at least one second spatial domain basis vector for characterizing the spatial domain characteristics of the first precoding matrix.

[0016] In yet another possible implementation, n=1, and X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

[0017] In this implementation, the precoding vectors corresponding to the X transmission layers of the first frequency domain unit of the second precoding matrix reported in the last measurement may be extracted to obtain at least one second spatial domain basis vector.

[0018] In another possible implementation, n is greater than 1, and the at least one second spatial basis vector is obtained based on an average value of precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0019] In this implementation, the average value of the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices is extracted to obtain at least one second spatial basis vector, which can improve the accuracy of the first precoding matrix with limited overhead or reduce the reporting overhead with the same reporting accuracy.

[0020] In another possible implementation, the n is greater than 1, and the at least one second spatial basis vector is obtained based on the singular value decomposition value of the covariance matrix obtained from the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0021] In this implementation, the singular value decomposition value of the covariance matrix obtained by extracting the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices is obtained to obtain at least one second spatial basis vector, which can improve the accuracy of the first precoding matrix.

[0022] In yet another possible implementation, X is less than or equal to a minimum value of the number of transmission layers corresponding to the n second precoding matrices.

[0023] In another possible implementation, the first frequency domain units are the same k frequency domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponds to K frequency domain units, and 1≤k≤K.

[0024] In another possible implementation, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and the at least one second spatial basis vector, including: the first precoding matrix is ​​obtained based on the orthogonalization result of the at least one first spatial basis vector and the at least one second spatial basis vector.

[0025] In this implementation, by orthogonalizing at least one first spatial basis vector and at least one second spatial basis vector, the set of spatial basis vectors obtained after orthogonalization can more accurately characterize the spatial characteristics of the first spatial basis vector with as few spatial basis vectors as possible, thereby improving the accuracy of the first precoding matrix under limited overhead or reducing the reporting overhead under the same reporting accuracy.

[0026] In a second aspect, a method for acquiring channel state information is provided. The method can be implemented by a network device, or a chip or circuit used for a network device.

[0027] The method includes: sending a first reference signal; receiving first information, the first information including indication information of at least one first spatial basis vector corresponding to a first precoding matrix, the first precoding matrix being obtained based on the at least one first spatial basis vector and at least one second spatial basis vector, the at least one second spatial basis vector being obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1; and obtaining the first precoding matrix based on the first information.

[0028] In this aspect, the network device receives the indication information of the spatial basis vectors corresponding to the precoding matrix reported by the terminal device. The network device can recover the precoding matrix based on the indication information of the spatial basis vectors reported by the terminal device and the historical measurement results; taking into account the slowly changing characteristics of the channel in the spatial domain, the partial spatial basis vectors determined according to the historical measurement results can better reflect the spatial characteristics of the precoding matrix to be reported, and only a small number of additional spatial basis vectors need to be indicated to correct the spatial beam direction, thereby saving the reporting overhead of the channel state information.

[0029] The at least one first spatial basis vector and the at least one second spatial basis vector are both used to characterize the spatial characteristics of the first precoding matrix. The at least one first spatial basis vector can be understood as being used to correct the spatial beam direction of the at least one second spatial basis vector, so that the set of spatial basis vectors consisting of the at least one first spatial basis vector and the at least one second spatial basis vector can better characterize the spatial characteristics of the first precoding matrix with as few spatial basis vectors as possible.

[0030] In a possible implementation, before sending the first reference signal, the method further includes: sending a second reference signal n times; and receiving indication information of the n second precoding matrices respectively based on the second reference signals sent n times.

[0031] In this implementation, the indication information of the n second precoding matrices is used to obtain at least one second spatial basis vector. The n second precoding matrices are precoding matrices obtained through historical measurement and reporting relative to the first precoding matrix.

[0032] In another possible implementation, the at least one second spatial basis vector is obtained based on precoding vectors corresponding to the x transmission layers of the first frequency domain unit in the n second precoding matrices.

[0033] In this implementation, since the spatial domain characteristics change slowly, at least one second spatial basis vector is obtained based on the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices, and is used to characterize the spatial domain characteristics of the first precoding matrix.

[0034] In yet another possible implementation, n=1, and X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

[0035] In this implementation, at least one second spatial basis vector is obtained based on the precoding vectors corresponding to the X transmission layers of the first frequency domain unit of the second precoding matrix reported in the last measurement.

[0036] In another possible implementation, n is greater than 1, and the at least one second spatial basis vector is obtained based on an average value of precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0037] In this implementation, at least one second spatial basis vector is obtained based on the average value of the precoding vectors corresponding to x transmission layers of the first frequency domain units of n second precoding matrices, which can improve the accuracy of the first precoding matrix with limited overhead or reduce the reporting overhead with the same reporting accuracy.

[0038] In another possible implementation, the n is greater than 1, and the at least one second spatial basis vector is obtained based on the singular value decomposition value of the covariance matrix obtained from the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0039] In this implementation, at least one second spatial basis vector is obtained based on the singular value decomposition value of the covariance matrix obtained from the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices, which can improve the accuracy of the first precoding matrix.

[0040] In yet another possible implementation, X is less than or equal to a minimum value of the number of transmission layers corresponding to the n second precoding matrices.

[0041] In another possible implementation, the first frequency domain units are the same k frequency domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponds to K frequency domain units, and 1≤k≤K.

[0042] In another possible implementation, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and the at least one second spatial basis vector, including: the first precoding matrix is ​​obtained based on the orthogonalization result of the at least one first spatial basis vector and the at least one second spatial basis vector.

[0043] In this implementation, by orthogonalizing at least one first spatial basis vector and at least one second spatial basis vector, the set of spatial basis vectors obtained after orthogonalization can more accurately characterize the spatial characteristics of the first spatial basis vector with as few spatial basis vectors as possible, thereby improving the accuracy of the first precoding matrix under limited overhead or reducing the reporting overhead under the same reporting accuracy.

[0044] In another possible implementation, obtaining the first precoding matrix based on the first information includes: obtaining the at least one second spatial basis vector based on the indication information of the n second precoding matrices; and obtaining the first precoding matrix based on the at least one first spatial basis vector and the at least one second spatial basis vector.

[0045] In this implementation, before the current measurement is reported, the network device has received indication information of n second precoding matrices. Therefore, based on the indication information of the n second precoding matrices, at least one second spatial basis vector can be obtained, and after receiving indication information of at least one first spatial basis vector, the first precoding matrix can be restored based on at least one first spatial basis vector and at least one second spatial basis vector.

[0046] In a third aspect, a communication device is provided. The communication device can implement the method of the first aspect or any implementation of the first aspect. For example, the communication device can be a chip or a terminal device. The method can be implemented through software, hardware, or hardware executing corresponding software.

[0047] In one possible implementation, the device includes: a transceiver unit and a processing unit; wherein: the transceiver unit is used to receive a first reference signal; the processing unit is used to generate first information based on the first reference signal, the first information including indication information of at least one first spatial basis vector corresponding to a first precoding matrix, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and at least one second spatial basis vector, the at least one second spatial basis vector is obtained based on n second precoding matrices, and n is a positive integer greater than or equal to 1; and the transceiver unit is also used to send the first information.

[0048] Optionally, the transceiver unit is further used to receive a second reference signal n times before receiving the first reference signal; and the transceiver unit is further used to send indication information of the n second precoding matrices respectively based on the second reference signals received n times.

[0049] Optionally, the at least one second spatial basis vector is obtained based on precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0050] Optionally, n=1, and X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

[0051] Optionally, n is greater than 1, and the at least one second spatial basis vector is obtained based on an average value of precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0052] Optionally, n is greater than 1, and the at least one second spatial basis vector is obtained based on the singular value decomposition value of the covariance matrix obtained from the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0053] Optionally, X is less than or equal to a minimum value of the number of transmission layers corresponding to the n second precoding matrices.

[0054] Optionally, the first frequency domain units are the same k frequency domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponds to K frequency domain units, and 1≤k≤K.

[0055] Optionally, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and the at least one second spatial basis vector, including: the first precoding matrix is ​​obtained based on the orthogonalization result of the at least one first spatial basis vector and the at least one second spatial basis vector.

[0056] For further features and beneficial effects, please refer to the relevant description in the first aspect.

[0057] In a fourth aspect, a communication device is provided. The communication device can implement the method of the second aspect or any implementation of the second aspect. For example, the communication device can be a chip or a network device. The method can be implemented through software, hardware, or hardware executing corresponding software.

[0058] In one possible implementation, the device includes: a transceiver unit and a processing unit; wherein: the transceiver unit is used to send a first reference signal; the transceiver unit is also used to receive first information, the first information including indication information of at least one first spatial basis vector corresponding to a first precoding matrix, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and at least one second spatial basis vector, the at least one second spatial basis vector is obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1; and the processing unit is used to obtain the first precoding matrix based on the first information.

[0059] Optionally, the transceiver unit is further used to send a second reference signal n times before sending the first reference signal; the transceiver unit is further used to receive indication information of the n second precoding matrices respectively based on the second reference signal sent n times.

[0060] Optionally, the at least one second spatial basis vector is obtained based on precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0061] Optionally, n=1, and X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

[0062] Optionally, n is greater than 1, and the at least one second spatial basis vector is obtained based on an average value of precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0063] Optionally, n is greater than 1, and the at least one second spatial basis vector is obtained based on the singular value decomposition value of the covariance matrix obtained from the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the n second precoding matrices.

[0064] Optionally, X is less than or equal to a minimum value of the number of transmission layers corresponding to the n second precoding matrices.

[0065] Optionally, the first frequency domain units are the same k frequency domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponds to K frequency domain units, and 1≤k≤K.

[0066] Optionally, the first precoding matrix is ​​obtained based on the at least one first spatial basis vector and the at least one second spatial basis vector, including: the first precoding matrix is ​​obtained based on the orthogonalization result of the at least one first spatial basis vector and the at least one second spatial basis vector.

[0067] Optionally, the processing unit is further used to obtain the at least one second spatial basis vector based on the indication information of the n second precoding matrices; and the processing unit is further used to obtain the first precoding matrix based on the at least one first spatial basis vector and the at least one second spatial basis vector.

[0068] For further features and beneficial effects, please refer to the relevant description in the second aspect.

[0069] In another possible implementation, the communication device in the third to fourth aspects above includes a processor coupled to a memory; the processor is configured to support the device in performing the corresponding functions in the above-mentioned channel state information reporting method. The memory is used to couple with the processor, which stores the necessary computer programs (or computer executable instructions) and / or data for the device. Optionally, the communication device may further include a communication interface for supporting communication between the device and other network elements, such as sending or receiving data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module or other type of communication interface. Optionally, the memory may be located inside the communication device and integrated with the processor; it may also be located outside the communication device.

[0070] In another possible implementation, the communication device in the third to fourth aspects includes a processor and a transceiver, the processor being coupled to the transceiver, and the processor being used to execute a computer program or instruction to control the transceiver to receive and send information; when the processor executes the computer program or instruction, the processor is also used to implement the above method through a logic circuit or executing code instructions. The transceiver may be a transceiver, a transceiver circuit, or an input / output interface, configured to receive signals from other communication devices other than the communication device and transmit them to the processor, or to send signals from the processor to other communication devices other than the communication device. When the communication device is a chip, the transceiver is a transceiver circuit or an input / output interface.

[0071] When the communication device in the third and fourth aspects above is a chip, the sending unit may be an output unit, such as an output circuit or a communication interface; the receiving unit may be an input unit, such as an input circuit or a communication interface. When the communication device is a terminal device, the sending unit may be a transmitter or a transmitter; and the receiving unit may be a receiver or a receiver.

[0072] In a fifth aspect, a communication system is provided, comprising the communication device as described in the third aspect or any one implementation of the third aspect, and the communication device as described in the fourth aspect or any one implementation of the fourth aspect.

[0073] In a sixth aspect, a computer-readable storage medium is provided, on which a computer program or instruction is stored. When the program or instruction is executed by a processor, it implements the method described in the first aspect or any one of the implementations of the first aspect, or implements the method described in the second aspect or any one of the implementations of the second aspect.

[0074] In a seventh aspect, a computer program product is provided, which, when executed on a computing device, implements the method described in the first aspect or any one of the implementations of the first aspect, or implements the method described in the second aspect or any one of the implementations of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] FIG1 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of the present application;

[0076] 2A to 2D are schematic diagrams of network architectures provided in embodiments of the present application;

[0077] FIG3 is a schematic diagram of a basic process of CSI estimation performed by a network device and a terminal device;

[0078] FIG4 is a schematic diagram of the structure of an existing PMI codebook;

[0079] FIG5 is a flow chart of a channel state information reporting method provided in an embodiment of the present application;

[0080] FIG6 is a schematic diagram of the structure of a PMI codebook provided in an embodiment of the present application;

[0081] FIG7 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0082] FIG8 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0083] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0084] The technical solution provided in this application can be applied to various communication systems, for example, it can be applied to 5G communication systems, future evolution systems or multiple communication convergence systems, etc., and can also be applied to existing communication systems, etc. The application scenarios of the technical solution provided in this application may include a variety of scenarios, such as machine to machine (M2M), macro and micro communications, enhanced mobile broadband (eMBB), ultra-high reliability and ultra-low latency communication (ultra-reliable&low latency communication, uRLLC) and massive machine type communication (mMTC). These scenarios may include but are not limited to: communication scenarios between terminal devices and terminal devices, communication scenarios between network devices and network devices, and communication scenarios between network devices and terminal devices. Among them, network devices include network devices and core network devices. The following description is based on the scenario of application to communication between network devices and terminal devices as an example.

[0085] Figure 1 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of the present application. As shown in Figure 1 , the communication system includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 may also include the Internet 300. The wireless access network 100 may include at least one network device (such as 110a and 110b in Figure 1 ) and at least one terminal device (such as 120a-120j in Figure 1 ). The terminal device is wirelessly connected to the network device, and the network device is wirelessly or wiredly connected to the core network. The core network device and the network device may be independent, distinct physical devices, or the core network device's functions and the network device's logical functions may be integrated into the same physical device, or a single physical device may integrate some of the core network device's functions and some of the network device's functions. Terminal devices and network devices may be interconnected via wired or wireless connections. Figure 1 is merely a schematic diagram. The communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1 .

[0086] Optionally, in actual applications, the wireless communication system may include multiple network devices (also called access network devices) and multiple terminal devices at the same time. A network device can serve one or more terminal devices at the same time. A terminal device can also access one or more network devices at the same time. The embodiments of the present application do not limit the number of terminal devices and network devices included in the wireless communication system.

[0087] The network device may be an entity on the network side for transmitting or receiving signals. The network device may be an access device for a terminal device to access the wireless communication system in a wireless manner, such as a base station. The base station can broadly cover various names as follows, or be replaced with the following names, such as: radio access network (RAN) node, NodeB, evolved NodeB (eNB), next generation NodeB (gNB), access network equipment in open radio access network (O-RAN), relay station, access point, transmission point (TRP), transmitting point (TP), master eNB (MeNB), secondary eNB (SeNB), multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, building baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), centralized unit (CU), distributed unit (DRU), etc. The network device may also refer to a mobile switching center and a device that performs base station functions in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, a network-side device in a 6G network, or a device that performs base station functions in future communication systems. The network device may support networks with the same or different access technologies.The embodiments of the present application do not limit the specific technology and specific device form adopted by the network device.

[0088] Network devices can be fixed or mobile. For example, base stations 110a and 110b are stationary and are responsible for wireless transmission and reception in one or more cells from terminal device 120. The helicopter or drone 120i shown in Figure 1 can be configured to act as a mobile base station, and one or more cells can move according to the location of the mobile base station 120i. In other examples, the helicopter or drone (120i) can be configured to act as a terminal device communicating with base station 110b.

[0089] In this application, the communication device used to implement the above-mentioned access network function can be an access network device, a network device having some of the access network functions, or a device capable of supporting the implementation of the access network function, such as a chip system, a hardware circuit, a software module, or a hardware circuit and a software module. The device can be installed in the access network device or used in combination with the access network device. In the method of this application, the communication device used to implement the access network device function is described as an access network device.

[0090] A terminal device may be an entity on the user side for receiving or transmitting signals, such as a mobile phone. The terminal device may be used to connect people, objects, and machines. The terminal device may communicate with one or more core networks through a network device. The terminal device includes a handheld device with wireless connection capabilities, other processing devices connected to a wireless modem, or a vehicle-mounted device. The terminal device may be a portable, pocket-sized, handheld, computer-built-in, or vehicle-mounted mobile device. The terminal device 120 may be widely used in various scenarios, such as cellular communication, D2D, V2X, point-to-point (P2P), machine-to-machine (M2M), machine type communication (MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, drones, robots, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery and mobility, etc.Some examples of the terminal device 120 include: user equipment (UE) of the 3GPP standard, fixed equipment, mobile equipment, handheld equipment, wearable equipment, cellular phones, smart phones, session initiated protocol (SIP) phones, laptops, personal computers, smart books, vehicles, satellites, global positioning system (GPS) equipment, target tracking equipment, drones, helicopters, aircraft, ships, remote control equipment, smart home equipment, industrial equipment, personal communication service (PCS) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), wireless network cameras, tablet computers, handheld computers, mobile internet devices (MIDs), wearable devices such as smart watches, VR devices, AR devices, wireless terminals in industrial control, terminals in vehicle networking systems, wireless terminals in self-driving, wireless terminals in smart grids, wireless terminals in transportation safety, and smart cities. The terminal device 120 may be a wireless terminal in the above various scenarios or a device for being set up in a wireless device, for example, a communication module, a modem or a chip in the above device. The terminal device may also be referred to as a terminal, a terminal device, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc. The terminal device may also be a terminal device in a future wireless communication system. The terminal device may be used in a dedicated network device or a general device. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal device.

[0091] Alternatively, a terminal device can function as a base station. For example, a UE can act as a dispatching entity, providing sidelink signals between UEs in V2X, D2D, or P2P scenarios. As shown in Figure 1, a cell phone 120a and a car 120b communicate with each other using sidelink signals. Cell phone 120a and smart home device 120e communicate without relaying the communication signals through base station 110b.

[0092] In this application, the communication device used to implement the functions of the terminal device can be a terminal device, or a terminal device with some of the functions of the above terminal devices, or a device that can support the implementation of the functions of the above terminal devices, such as a chip system, which can be installed in the terminal device or used in combination with the terminal device. In this application, the chip system can be composed of chips, or it can include chips and other discrete devices. In the technical solution provided in this application, the communication device is described as a terminal device or UE as an example.

[0093] Optionally, a wireless communication system is typically composed of cells, with base stations providing cell management and communication services to multiple mobile stations (MS) in the cell. The base station includes a baseband unit (BBU) and a remote radio unit (RRU). The BBU and RRU can be placed in different locations, for example: the RRU is remote and placed in an area with high traffic volume, while the BBU is placed in a central computer room. The BBU and RRU can also be placed in the same computer room. The BBU and RRU can also be different components under the same rack. Optionally, a cell can correspond to a carrier or component carrier.

[0094] In some deployments, the network devices mentioned in the embodiments of the present application may include a CU, a DU, or both a CU and a DU, or a control plane CU node (central unit-control plane (CU-CP)), a user plane CU node (central unit-user plane (CU-UP)), and a DU node. For example, the network devices may include a gNB-CU-CP, a gNB-CU-UP, and a gNB-DU.

[0095] In some deployments, multiple RAN nodes collaborate to assist terminals in achieving wireless access, with different RAN nodes implementing portions of the base station's functionality. For example, a RAN node can be a CU, DU, CU-CP, CU-UP, or RU. The CU and DU can be separate or included in the same network element, such as the BBU. The RU can be included in a radio frequency device or radio unit, such as an RRU, AAU, or RRH.

[0096] The RAN node may support one or more types of fronthaul interfaces, with different fronthaul interfaces corresponding to DUs and RUs with different functions. If the fronthaul interface between the DU and the RU is a common public radio interface (CPRI), the DU is configured to implement one or more baseband functions, and the RU is configured to implement one or more radio frequency functions. If the fronthaul interface between the DU and the RU is another type of interface, relative to the CPRI, some of the downlink and / or uplink baseband functions, such as precoding, digital beamforming (BF), or one or more of inverse fast Fourier transform (IFFT) / cyclic prefix (CP) for downlink, are moved from the DU to the RU for implementation; and for uplink, one or more of digital beamforming (BF), or fast Fourier transform (IFFT) / cyclic prefix (CP) removal, are moved from the DU to the RU for implementation. In one possible implementation, the interface may be an enhanced common public radio interface (eCPRI). In the eCPRI architecture, the division between the DU and RU is different, corresponding to different types (category, Cat) of eCPRI, such as eCPRI Cat A, B, C, D, E, and F.

[0097] Taking eCPRI Cat A as an example, for downlink transmission, based on layer mapping, the DU is configured to implement layer mapping and one or more functions preceding it (i.e., one or more of coding, rate matching, scrambling, modulation, and layer mapping). Other functions after layer mapping (e.g., RE mapping, digital beamforming (BF), or one or more of inverse fast Fourier transform (IFFT) / cyclic prefix (CP) addition) are moved to the RU for implementation. For uplink transmission, based on RE demapping, the DU is configured to implement demapping and one or more functions preceding it (i.e., one or more of decoding, rate matching, descrambling, demodulation, inverse discrete Fourier transform (IDFT), channel equalization, and RE demapping). Other functions after demapping (e.g., one or more of digital BF or fast Fourier transform (FFT) / CP removal) are moved to the RU for implementation. It is understandable that for the functional description of DU and RU corresponding to various types of eCPRI, reference can be made to the eCPRI protocol, which will not be described in detail here.

[0098] In one possible design, the processing unit for implementing baseband functions in the BBU is called a baseband high layer (BBH) unit, and the processing unit for implementing baseband functions in the RRU / AAU / RRH is called a baseband low layer (BBL) unit.

[0099] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. Any unit of 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.

[0100] In the embodiments of the present application, the device for implementing the functions of the network device can be a network device; it can also be a device that can support the network device to implement the functions, such as a chip system, a hardware circuit, a software module, or a hardware circuit and a software module. The device can be installed in the network device or used in conjunction with the network device. In the embodiments of the present application, only the device for implementing the functions of the network device is used as an example to illustrate, and does not constitute a limitation on the solutions of the embodiments of the present application.

[0101] It is understandable that the present application can be applied between network devices and terminal devices.

[0102] The communication between the network device and the terminal device follows a certain protocol layer structure. The protocol layer structure may include a control plane protocol layer structure and a user plane protocol layer structure. For example, the control plane protocol layer structure may include the functions of the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the medium access control (MAC) layer, and the physical layer. For example, the user plane protocol layer structure may include the functions of the PDCP layer, the RLC layer, the MAC layer, and the physical layer. In one possible implementation, a service data adaptation protocol (SDAP) layer may also be included above the PDCP layer.

[0103] Optionally, the protocol layer structure between the network device and the terminal device may further include an artificial intelligence (AI) layer for transmitting data related to AI functions.

[0104] Taking data transmission between network devices and terminal devices as an example, data transmission needs to pass through the user plane protocol layers, such as the SDAP layer, PDCP layer, RLC layer, MAC layer, and physical layer. The SDAP layer, PDCP layer, RLC layer, MAC layer, and physical layer can also be collectively referred to as the access layer. Data transmission is divided into sending or receiving based on the direction of transmission, and each of these layers is further divided into a sending part and a receiving part. Taking downlink data transmission as an example, after the PDCP layer obtains data from the upper layer, it transmits the data to the RLC layer and MAC layer. The MAC layer then generates a transport block, which is then wirelessly transmitted through the physical layer. Data is encapsulated accordingly in each layer. For example, data received by a layer from the layer above it is considered a service data unit (SDU) of that layer. After encapsulation by that layer, it becomes a protocol data unit (PDU) and is then passed to the next layer.

[0105] For example, a terminal device may also include an application layer and a non-access layer. The application layer can be used to provide services to applications installed in the terminal device. For example, downlink data received by the terminal device can be sequentially transmitted from the physical layer to the application layer, which then provides it to the application. For another example, the application layer can obtain data generated by the application and sequentially transmit the data to the physical layer for transmission to other communication devices. The non-access layer can be used to forward user data, such as forwarding uplink data received from the application layer to the SDAP layer, or forwarding downlink data received from the SDAP layer to the application layer.

[0106] In order to support AI technology in wireless networks, AI nodes may also be introduced into the network.

[0107] Optionally, the AI ​​node can be deployed in one or more of the following locations in the communication system: access network equipment, terminal equipment, or core network equipment. Alternatively, the AI ​​node can be deployed separately, for example, in a location other than any of the above devices, such as a host or cloud server in an over-the-top (OTT) system. The AI ​​node can communicate with other devices in the communication system, such as one or more of the following: network equipment, terminal equipment, or network elements of the core network.

[0108] It is understood that this application does not limit the number of AI nodes. For example, when there are multiple AI nodes, the multiple AI nodes can be divided based on function, such as different AI nodes are responsible for different functions.

[0109] It can also be understood that AI nodes can be independent devices, or they can be integrated into the same device to implement different functions, or they can be network elements in hardware devices, or they can be software functions running on dedicated hardware, or they can be virtualized functions instantiated on a platform (for example, a cloud platform). This application does not limit the specific form of the above-mentioned AI nodes.

[0110] An AI node can be an AI network element or an AI module.

[0111] One or more AI modules are provided in one or more of these network element nodes, such as core network equipment, access network nodes (RAN nodes), terminals or OAM devices. The access network node can be a separate RAN node, or it can include multiple RAN nodes, for example, including CU and DU. The CU and / or DU can also be provided with one or more AI modules. Optionally, the CU can also be split into CU-CP and CU-UP. One or more AI models are provided in the CU-CP and / or CU-UP.

[0112] The AI ​​module is used to implement the corresponding AI function. The AI ​​modules deployed in different network elements can be the same or different. The model of the AI ​​module can implement different functions according to different parameter configurations. The model of the AI ​​module can be configured based on one or more of the following parameters: structural parameters (such as the number of neural network layers, the width of the neural network, the connection relationship between layers, the weight of the neuron, the activation function of the neuron, or at least one of the bias in the activation function), input parameters (such as the type of input parameters and / or the dimension of the input parameters), or output parameters (such as the type of output parameters and / or the dimension of the output parameters). Among them, the bias in the activation function can also be called the bias of the neural network.

[0113] An AI module can have one or more models. A model can infer an output, which includes one or more parameters. The learning, training, or inference processes of different models can be deployed on different nodes or devices, or on the same node or device.

[0114] The communication system includes a RAN intelligent controller (RIC). For example, the RIC can be the above-mentioned AI module, which is used to implement AI-related functions. The RIC includes a near-real-time RIC (near-real time RIC, near-RT RIC) and a non-real-time RIC (non-real time RIC, Non-RT RIC). Among them, the non-real-time RIC mainly processes non-real-time information, such as data that is not sensitive to delay, and the delay of the data can be in the order of seconds. The real-time RIC mainly processes near-real-time information, such as data that is relatively sensitive to delay, and the delay of the data is in the order of tens of milliseconds.

[0115] Near real-time RIC is used for model training and reasoning. For example, it is used to train an AI model and use the AI ​​model for reasoning. Near real-time RIC can obtain network-side and / or terminal-side information from RAN nodes (e.g., CU, CU-CP, CU-UP, DU, and / or RU) and / or terminals. This information can be used as training data or reasoning data. Optionally, near real-time RIC can deliver the reasoning results to the RAN node and / or terminal. Optionally, the reasoning results can be exchanged between the CU and DU, and / or between the DU and RU. For example, the near real-time RIC delivers the reasoning results to the DU, and the DU sends it to the RU.

[0116] Non-real-time RIC is also used for model training and reasoning. For example, it is used to train AI models and use the models for reasoning. Non-real-time RIC can obtain network-side and / or terminal-side information from RAN nodes (such as CU, CU-CP, CU-UP, DU and / or RU) and / or terminals. This information can be used as training data or reasoning data, and the reasoning results can be submitted to the RAN node and / or terminal. Optionally, the reasoning results can be exchanged between the CU and DU, and / or between the DU and RU. For example, the non-real-time RIC submits the reasoning results to the DU, and the DU sends it to the RU.

[0117] The near-real-time RIC and non-real-time RIC can also be set up as separate network elements. Optionally, the near-real-time RIC and non-real-time RIC can also be part of other devices. For example, the near-real-time RIC is set up in a RAN node (e.g., a CU or DU), while the non-real-time RIC is set up in an OAM, a cloud server, a core network device, or other network devices.

[0118] For example, the configuration of near real-time RIC and non-real-time RIC in the network architecture may be as shown in FIG. 2A to FIG. 2D :

[0119] As shown in (a) of FIG. 2A , in a first possible implementation, the access network device includes a near real-time RIC module for performing model learning and / or reasoning.

[0120] As shown in (b) of FIG2A , in a second possible implementation, in a communication system, a non-real-time RIC may be included outside the access network device. Optionally, the non-real-time RIC may be located in the OAM or in the core network device.

[0121] As shown in (c) of Figure 2A, in a third possible implementation, the access network device includes a near real-time RIC, and a non-real-time RIC is also included outside the access network device. Optionally, the non-real-time RIC can be located in the OAM or core network device.

[0122] Compared to (c) in Figure 2A, the CU is separated into CU-CP and CU-UP in Figure 2B. The settings of near-real-time RIC and non-real-time RIC are the same as those in (c) in Figure 2A.

[0123] As shown in Figure 2C, optionally, the access network device includes one or more AI entities, and the function of the AI ​​entity is similar to the above-mentioned near real-time RIC. Optionally, the OAM includes one or more AI entities, and the function of the AI ​​entity is similar to the above-mentioned non-real-time RIC. Optionally, the core network device includes one or more AI entities, and the function of the AI ​​entity is similar to the above-mentioned non-real-time RIC. When both the OAM and the core network device include AI entities, the models trained by their respective AI entities are different, and / or the models used for reasoning are different. In the present application, the difference in models may include at least one of the following differences: structural parameters of the model (such as the number of layers and / or weights of the model), input parameters of the model, or output parameters of the model.

[0124] Relative to Figure 2C, the access network device in Figure 2D is separated into CU and DU. Optionally, the CU may include an AI entity, and the function of the AI ​​entity is similar to the above-mentioned near real-time RIC. Optionally, the DU may include an AI entity, and the function of the AI ​​entity is similar to the above-mentioned near real-time RIC. When both the CU and the DU include AI entities, the models trained by their respective AI entities are different, and / or the models used for reasoning are different. Optionally, the CU in Figure 2D can be further split into CU-CP and CU-UP. Optionally, one or more AI models can be deployed in the CU-CP. And / or, one or more AI models can be deployed in the CU-UP. Optionally, in Figure 2C or Figure 2D, the OAM of the access network device and the OAM of the core network device can be deployed separately and independently.

[0125] It should be understood that the number and type of each device in the communication system shown in Figure 1 are for illustration only, and the present application is not limited to this. In actual applications, the communication system may also include more terminal devices, more access network devices, and other network elements, such as core network devices, and / or network elements for implementing artificial intelligence functions.

[0126] It is understandable that all or part of the functions implemented by one or more of the terminal equipment, access network equipment, core network equipment, or network elements for implementing artificial intelligence functions can be virtualized, that is, implemented by one or more of the proprietary processors or general-purpose processors and the corresponding software modules. Among them, since the terminal equipment and the access network equipment involve interfaces for air interface transmission, the transceiver functions of the interfaces can be implemented by hardware. Core network equipment, such as operation administration and maintenance (OAM) network elements, can be virtualized. Optionally, one or more functions of the virtualized terminal equipment, access network equipment, core network equipment, or network elements for implementing artificial intelligence functions can be implemented by cloud devices, such as cloud devices in over the top (OTT) systems.

[0127] Taking 5G communication systems as an example, 5G communication systems have higher requirements for system capacity and spectral efficiency. In 5G communication systems, the application of massive multiple-input multiple-output (MIMO) technology plays a crucial role in improving the system's spectral efficiency. When using multiple-input multiple-output (MIMO) technology, network equipment needs to precode data before sending it to terminal devices. The method of precoding depends on the downlink channel CSI reported by the terminal device to the network equipment. Therefore, accurate CSI information is a key factor affecting system performance.

[0128] In a time division duplexing (TDD) system, uplink and downlink channels transmit signals on different time resources within the same frequency domain. Within a relatively short period of time (the coherence time of channel propagation), the signals on the uplink and downlink channels can be assumed to experience the same channel fading, thus demonstrating reciprocity. The base station can leverage this channel reciprocity to obtain the downlink CSI from the uplink channel for precoding.

[0129] In FDD systems, however, because the separation between the uplink and downlink frequency bands is greater than the bandwidth, there is no complete reciprocity between the uplink and downlink channels. In traditional FDD systems, uplink and downlink channel reciprocity cannot be utilized, and the terminal device is required to report the CSI of the downlink channel to the network device. Figure 3 shows a basic flow chart of CSI estimation between the network device and the terminal device. The flow includes the following steps: S301. The network device must first send channel measurement configuration information to the terminal device. This configuration information is used to configure the channel measurement, notifying the terminal device of the timing and behavior of the channel measurement, that is, telling the terminal device which resource to measure the channel state information-reference signal (CSI-RS); S302. The network device sends the CSI-RS to the terminal device for channel measurement; S303. The terminal device performs measurements based on the CSI-RS sent by the network device, calculates the final CSI reporting value, and reports the CSI to the network device; and S304. The network device then sends data based on the CSI reported by the terminal device. Among them, the network device is used to determine the number of streams for transmitting data to the terminal device based on the channel rank indicator (RI) reported by the terminal device; the network device is used to determine the modulation order and channel coding code rate for transmitting data to the terminal device based on the channel quality indicator (CQI) reported by the terminal device; the network device is used to determine the precoding of data transmitted to the terminal device based on the PMI reported by the terminal device.

[0130] PMI reporting is determined and reported based on a set of codebooks. The design of the FDD CSI codebook is a basic and important issue in the 5G communication system.

[0131] In the current standard protocol of new radio (NR), FDD CSI reporting uses base station side information as a reference for channel quantization, and the PMI reported by the UE is determined based on at least one main channel eigenvector with the base station side as the transmitter. The first codebook adopts the idea of ​​spatial (angle) compression, and represents multiple main eigenvectors (i.e., the precoding matrix of a single user) with a linear combination of several discrete Fourier transform (DFT) basis vectors in the spatial domain. The second codebook, based on the first codebook, further compresses the frequency domain (time delay) by utilizing the frequency domain correlation of the amplitude and phase coefficients of different sub-bands, and represents the main eigenvector with a bilinear combination of several spatial DFT basis vectors and several frequency domain DFT basis vectors. As shown in Figure 4, it is a structural diagram of the existing PMI codebook of NR standard protocol version 16 (R16) type IIT (type II). The codebook structure of the second codebook is PMI is the precoding of one or more transmission layers in multiple frequency domain units, where the number of transmission layers R is determined by the value reported by RI; the frequency domain unit can be the number of subbands or the number of resource blocks (RBs). W in the codebook structure is a precoding matrix of space-frequency dimension composed of the precoding vectors (dimension P×1) to be reported for the N3 frequency domain units corresponding to each transmission layer in the R transmission layers. The dimension is P×N3, where P is the number of ports on the base station side. Considering polarization, P=2N1*N2, where N1 and N2 are the number of horizontal and vertical ports respectively, and N3 is the number of frequency domain units; W1 is the selected set of spatial DFT basis vectors, are L orthogonal DFT basis vectors of dimension N1*N2×1 corresponding to two polarizations; W f The conjugate transposed matrix of is the selected frequency domain DFT basis vector set, are M orthogonal DFT basis vectors of dimension N3×1; The UE reports 2L spatial basis vectors and M frequency basis vectors, which correspond to 2LM linear combination coefficients. The UE only needs to select a number of non-zero coefficients to report, and the non-zero coefficients to be reported are indicated by a bitmap. The UE's PMI reporting includes information indicating the spatial basis vectors, frequency basis vectors, the amplitude and phase of the non-zero linear combination coefficients, and a bitmap indicating the location of the non-zero coefficients. The base station recovers the precoding matrix based on the UE's reporting.

[0132] Based on the codebook, the UE uses the currently measured channel characteristics to report the corresponding PMI in real time, which results in significant reporting overhead. The inventors discovered that the spatial characteristics of the channel change slowly over time. It is worthwhile to explore how to leverage these slowly varying spatial characteristics of the channel to reduce the CSI reporting overhead.

[0133] To address the problem of high CSI reporting overhead, the present application provides a CSI reporting solution, in which the terminal device determines part of the spatial basis vectors based on historical measurement results, and only needs to report the indication information of the remaining part of the spatial basis vectors corresponding to the precoding matrix, so that the network device can determine part of the spatial basis vectors based on the indication information of the spatial basis vectors reported by the terminal device and the historical measurement results, and recover the precoding matrix; taking into account the slowly varying characteristics of the channel in the spatial domain, the part of the spatial basis vectors determined according to the historical measurement results can better reflect the spatial characteristics of the precoding matrix to be reported, and only a small number of additional spatial basis vectors need to be indicated to correct the spatial beam direction, thereby saving the reporting overhead of the channel state information.

[0134] The following describes in detail the channel state information reporting method provided by the embodiment of the present application with reference to the accompanying drawings:

[0135] FIG5 is a flow chart of a method for reporting channel state information provided in an embodiment of the present application. Exemplarily, the method may include the following steps:

[0136] S501. The terminal device sends indication information of n second precoding matrices based on the second reference signals received n times. Correspondingly, the network device receives the indication information of the n second precoding matrices.

[0137] The network device can send a reference signal to the terminal device periodically or based on event triggering, and the terminal device measures the reference signal sent by the network device each time, generates indication information of the second precoding matrix, and reports the indication information of the second precoding matrix to the network device.

[0138] In this embodiment, the network device sends the second reference signal n times, and the terminal device sends indication information of n second precoding matrices to the network device, where n is a positive integer greater than or equal to 1.

[0139] Exemplarily, the terminal device can use an existing method (for example, based on the first codebook or the second codebook mentioned above) to send indication information of n second precoding matrices, that is, the indication information of each second precoding matrix includes indication information for representing all spatial basis vectors corresponding to the second precoding matrix; it can also send indication information of n second precoding matrices based on the scheme of the present application, that is, for each second precoding matrix, the set of spatial basis vectors corresponding to the second precoding matrix includes two parts of spatial basis vectors, one part of the spatial basis vectors is determined according to the precoding matrix obtained by several measurements before the measurement corresponding to the second precoding matrix, and the other part of the spatial basis vectors is selected from a predefined set of spatial basis vectors. At this time, only the indication information of the other part of the spatial basis vectors is sent.

[0140] The embodiments of the present application mainly describe the reporting of spatial channel state information. In fact, the indication information of the second precoding matrix may also include indication information of frequency domain basis vectors, amplitude and phase indication information of non-zero linear combination coefficients, and a bitmap indicating the position of non-zero coefficients.

[0141] It is understandable that the network device may also obtain the indication information of the n second precoding matrices in other ways. Therefore, this step is optional and is indicated by a dotted line in the figure.

[0142] Exemplarily, the second reference signal may be a channel state information-reference signal (CSI-RS) or a demodulation reference signal (DMRS), etc. The embodiment of the present application does not limit the type of the second reference signal.

[0143] S502: The network device sends a first reference signal to the terminal device. Correspondingly, the terminal device receives the first reference signal.

[0144] In step S501, the network device sends the second reference signal to the terminal device n times. Compared with this step, this is a historical behavior, which is a behavior before the current CSI measurement and reporting in terms of time.

[0145] In this step, the network device may send a first reference signal to the terminal device again. The first reference signal may be the same as or different from the second reference signal sent n times by the network device in step S501.

[0146] S503: The terminal device sends first information to the network device based on the first reference signal. Correspondingly, the network device receives the first information.

[0147] After receiving the first reference signal, the terminal device measures the first reference signal and determines a first precoding matrix based on the measurement result and the codebook structure shown in FIG6 :

[0148] in, is the precoding matrix of the space-frequency dimension for this measurement (the tth measurement). Its dimension is P*N3, that is, N3 precoding vectors of dimension P*1 are combined into a space-frequency matrix. For example, t≥n+1.

[0149] in, W S is a set of spatial basis vectors used to determine the first precoding matrix, W S It consists of two parts, where W0 contains at least one second spatial basis vector with a dimension of P*X, and contains X second spatial basis vectors, which are obtained based on the precoding vectors corresponding to the X transmission layers of the first frequency domain unit of the second precoding matrix reported based on n historical measurements. 2L′ (two polarization directions, each with the same L′ polarization) first spatial basis vectors selected from a preconfigured or predefined set of spatial basis vectors, determined based on this measurement. It should be understood that if there is only one polarization direction, 2L′ is replaced by L′ below.

[0150] There are (X+2L′)M linear combination coefficients corresponding to (X+2L′) spatial basis vectors and M frequency domain basis vectors. The terminal device only needs to select several non-zero coefficients to report, and the non-zero coefficients that need to be reported are indicated by a bitmap.

[0151] W f The conjugate transposed matrix of is the selected frequency domain DFT basis vector set, are M orthogonal DFT basis vectors of dimension N3×1.

[0152] In this embodiment, the terminal device sends first information to the network device, where the first information includes indication information of at least one first spatial basis vector corresponding to the first precoding matrix, that is, indication information of the 2L′ spatial DFT basis vectors selected above. Exemplarily, the first information may include indices of the same L′ spatial DFT basis vectors selected for two polarization directions.

[0153] In this embodiment, the protocol needs to specify, or the network device and the terminal device need to negotiate, the design of the spatial basis vectors, so that at least one second spatial basis vector representing the first precoding matrix can be determined based on the n second precoding matrices obtained from historical measurements. Exemplarily, W0 is obtained based on the precoding vectors corresponding to the x transmission layers of the first frequency domain unit in the n second precoding matrices.

[0154] Furthermore, W0 can be obtained in the following ways:

[0155] One implementation manner is that n=1, and W0 is obtained based on the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the second precoding matrix obtained in the last measurement.

[0156] The first frequency domain unit is the same k frequency domain units corresponding to the second precoding matrix obtained in the last measurement (t-1th measurement). Each second precoding matrix in the second precoding matrix obtained in the last measurement corresponds to K frequency domain units, 1≤k≤K.

[0157] For example, based on the second precoding matrix obtained in the last measurement, the precoding vectors corresponding to the first X transmission layers of a frequency domain unit (which can be any frequency domain unit among K frequency domain units, such as the j-th frequency domain unit, 1≤j≤K) can be extracted as W0. W0 satisfies the following formula 1:

[0158] in, Represents R on the jth frequency domain unit t-1The precoding matrix consists of the precoding vectors corresponding to the transmission layers, and the dimension is P*R t-1 ; Indicates taking the first X column vectors of the matrix.

[0159] For another example, the average value of the precoding vectors corresponding to the first X transmission layers of the k frequency domain units may be extracted according to the second precoding matrix obtained in the last measurement as W0, where W0 satisfies the following formula 2:

[0160] Here, k can be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0161] in, It represents an index set of k frequency domain units extracted from K frequency domain units. Which k frequency domain units are extracted from the K frequency domain units may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0162] Here, X may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0163] For example, if X is predefined by the protocol, then X is equal to the number of transmission layers R corresponding to the second precoding matrix obtained in the last measurement. t-1 .

[0164] Exemplarily, if X is configured by the network device or reported by the terminal device, then X is less than or equal to the number of transmission layers R corresponding to the second precoding matrix obtained in the last measurement. t-1 .

[0165] In this implementation, the precoding vectors corresponding to the X transmission layers of the first frequency domain unit of the second precoding matrix reported in the last measurement may be extracted to obtain at least one second spatial basis vector.

[0166] In another implementation, n is greater than 1, and W0 is obtained based on the average value of the precoding vectors corresponding to the x transmission layers of the first frequency domain elements in the n second precoding matrices, and W0 satisfies the following formula 3:

[0167] in, Represents R on the jth frequency domain unit t-i The precoding matrix consists of the precoding vectors corresponding to the transmission layers, and the dimension is P*R t-i .

[0168] The first frequency domain unit is the same k frequency domain units corresponding to the second precoding matrix obtained in the last measurement (t-1th measurement). Each second precoding matrix in the second precoding matrix obtained in the last measurement corresponds to K frequency domain units, 1≤k≤K.

[0169] In Formula 3, the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in each of the n second precoding matrices are first obtained, and then the average value of the n precoding vectors is obtained.

[0170] The value of n may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0171] Here, k can be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0172] in, It represents an index set of k frequency domain units extracted from K frequency domain units. Which k frequency domain units are extracted from the K frequency domain units may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0173] Here, X may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0174] For example, if X is predefined by the protocol, then X is equal to the minimum value of the number of transmission layers corresponding to the n second precoding matrices, that is, X=min{R t-i |i=1,…,n}.

[0175] Exemplarily, if X is configured by the network device or reported by the terminal device, then X is less than or equal to the minimum value of the number of transmission layers corresponding to the n second precoding matrices, that is, X≤min{R t-i |i=1,…,n}.

[0176] In this implementation, the average value of the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices is extracted to obtain at least one second spatial basis vector, which can improve the accuracy of the first precoding matrix with limited overhead or reduce the reporting overhead with the same reporting accuracy.

[0177] Another implementation is that n is greater than 1, and W0 is the covariance matrix obtained based on the precoding vectors corresponding to the X transmission layers of the first frequency domain unit in the n second precoding matrices The singular value decomposition (SVD) result is obtained, W0 is the covariance matrix The first X column vectors corresponding to the decomposed right unitary matrix are: Satisfies the following formula 4:

[0178] in, Represents R on the kth frequency domain unit t-i The precoding matrix consists of the precoding vectors corresponding to the transmission layers, and the dimension is P*R t-i . for The conjugate transposed matrix of .

[0179] The first frequency domain unit is the same k frequency domain units corresponding to the second precoding matrix obtained in the last measurement (t-1th measurement). Each second precoding matrix in the second precoding matrix obtained in the last measurement corresponds to K frequency domain units, 1≤k≤K.

[0180] The value of n may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0181] Here, k can be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0182] in, It represents an index set of k frequency domain units extracted from K frequency domain units. Which k frequency domain units are extracted from the K frequency domain units may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0183] Here, X may be predefined by the protocol, configured by the network device, or reported by the terminal device.

[0184] For example, if X is predefined by the protocol, then X is equal to the minimum value of the number of transmission layers corresponding to the n second precoding matrices, that is, X=min{R t-i |i=1,…,n}.

[0185] Exemplarily, if X is configured by the network device or reported by the terminal device, then X is less than or equal to the minimum value of the number of transmission layers corresponding to the n second precoding matrices, that is, X≤min{R t-i |i=1,…,n}.

[0186] In this implementation, the singular value decomposition value of the covariance matrix obtained by extracting the precoding vectors corresponding to the X transmission layers of the first frequency domain units of the n second precoding matrices is obtained to obtain at least one second spatial basis vector, which can improve the accuracy of the first precoding matrix.

[0187] It can be seen that this embodiment proposes a spatial differential CSI reporting scheme, which uses at least one spatial basis vector (i.e., W0) determined based on n second precoding matrices as part of the spatial basis, and combines it with several selected DFT basis vectors (here, 2L′ spatial DFT basis vectors) to form a spatial basis for spatial compression. Therefore, it can be understood that the first precoding matrix is ​​obtained based on at least one first spatial basis vector and at least one second spatial basis vector.

[0188] It can be understood that the at least one first spatial basis vector and the at least one second spatial basis vector are both used to characterize the spatial characteristics of the first precoding matrix. The at least one first spatial basis vector can be understood to be used to correct the spatial beam direction of the at least one second spatial basis vector, so that the spatial basis vector set consisting of the at least one first spatial basis vector and the at least one second spatial basis vector can better characterize the spatial characteristics of the first precoding matrix using as few spatial basis vectors as possible.

[0189] In order to further save reporting overhead, the first precoding matrix may also be obtained based on an orthogonalization result of at least one first spatial basis vector and at least one second spatial basis vector, that is: This application does not limit the orthogonalization method. For example, the Gram-Schmidt orthogonalization method or the Householder transform can be used to perform the orthogonalization operation on the basis vectors. In this implementation, by orthogonalizing at least one first spatial basis vector and at least one second spatial basis vector, the set of spatial basis vectors obtained after orthogonalization can more accurately characterize the spatial characteristics of the first spatial basis vector with as few spatial basis vectors as possible, thereby improving the accuracy of the first precoding matrix under limited overhead or reducing the reporting overhead under the same reporting accuracy.

[0190] The embodiment of the present application mainly describes the reporting of spatial channel state information. In fact, the first information may also include frequency domain basis vectors (i.e., the above ) indication information, non-zero linear combination coefficients (i.e. the above )'s amplitude and phase indication information and a bitmap indicating the positions of non-zero coefficients.

[0191] S504. The network device obtains a first precoding matrix based on the first information.

[0192] After receiving the first information, the network device may parse and obtain information indicating at least one first spatial basis vector of the first precoding matrix. Furthermore, the network device may obtain at least one second spatial basis vector based on the information indicating the n second precoding matrices received in step S501. The network device then restores the first precoding matrix based on the at least one first spatial basis vector and the at least one second spatial basis vector.

[0193] The network device may obtain at least one second spatial basis vector based on the indication information of the n second precoding matrices in the same manner as the terminal device obtains at least one second spatial basis vector.

[0194] It should be noted that if the above-mentioned first precoding matrix can also be obtained based on the orthogonalization result of at least one first spatial basis vector and at least one second spatial basis vector, the network device, after obtaining the at least one first spatial basis vector and the at least one second spatial basis vector, first performs orthogonalization processing on the at least one first spatial basis vector and the at least one second spatial basis vector, and then obtains W S , and finally based on W S Restore the first precoding matrix.

[0195] Thus, the network device can perform data transmission with the terminal device based on the first precoding matrix.

[0196] In this embodiment, the terminal device and the network device obtain at least one second spatial basis vector in the same way and construct the spatial basis in the same way. Therefore, after receiving the indication information of at least one first spatial basis vector of the first precoding matrix reported by the terminal device, the network device can restore the first precoding matrix.

[0197] According to a channel state information reporting method provided by an embodiment of the present application, a terminal device determines part of the spatial basis vectors based on historical measurement results, and only needs to report the indication information of the remaining part of the spatial basis vectors corresponding to the precoding matrix, so that the network device can determine part of the spatial basis vectors based on the indication information of the spatial basis vectors reported by the terminal device and the historical measurement results, and recover the precoding matrix; taking into account the slowly varying characteristics of the channel in the spatial domain, the part of the spatial basis vectors determined according to the historical measurement results can better reflect the spatial characteristics of the precoding matrix to be reported, and only a small number of additional spatial basis vectors need to be indicated to correct the spatial beam direction, thereby saving the reporting overhead of the channel state information.

[0198] In this application, "sending information to... (e.g., a terminal device)" or the related illustrations in the accompanying drawings can be understood as the destination end of the information being the terminal device. This can include sending information to the terminal device directly or indirectly. "Receiving information from... (e.g., a terminal device)" or "receiving information from... (e.g., a terminal device)", or the related illustrations in the accompanying drawings can be understood as the source end of the information being the terminal device, which can include receiving information from the terminal device directly or indirectly. The information may be processed as necessary between the source end and the destination end of the information transmission, such as format changes, etc., but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood similarly and will not be repeated here.

[0199] It is understandable that this application uses terminal devices and network devices as examples of the execution entities of the interaction diagram, but this application does not limit the execution entities of the interaction diagram. For example, the terminal device in the method provided by this application can also be a chip, chip system, or processor applied to the terminal device, or a logical node, logical module, or software that can implement all or part of the terminal device; the network device in the method provided by this application can also be a chip, chip system, or processor applied to the network device, or a logical node, logical module, or software that can implement all or part of the network device functions.

[0200] It is understood that in order to implement the functions in the above embodiments, the network devices and terminal devices include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0201] Figures 7 and 8 are schematic diagrams of the structures of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or network device in the above-mentioned method embodiments, thereby also achieving the beneficial effects possessed by the above-mentioned method embodiments. In the embodiments of the present application, the communication device can be one of the terminal devices 120a-120j shown in Figure 1, or it can be the network device 110a or 110b shown in Figure 1, or it can be a module (such as a chip) applied to the terminal device or network device.

[0202] As shown in Figure 7 , a communication device 700 includes a processing unit 710 and a transceiver unit 720. The communication device 700 is used to implement the functions of the terminal device or network device in the method embodiment shown in Figure 5 above.

[0203] When the communication apparatus 700 is used to implement the functions of the terminal device in the method embodiment shown in FIG5 : the transceiver unit 720 is used to implement the functions of the terminal device in steps S501 to S503 in the embodiment shown in FIG5 .

[0204] When the communication device 700 is used to implement the functions of the network device in the method embodiment shown in Figure 5: the transceiver unit 720 is used to implement the functions of the network device in steps S501 to S503 in the embodiment shown in Figure 5, and the processing unit 710 is used to implement step S504 in the embodiment shown in Figure 5. For example, the transceiver unit 720 can be deployed on the DU or RU in Figures 2A and 2B, and the processing unit 710 can be deployed on the DU in Figures 2A and 2B; or the functions of the processing unit 710 can be partially deployed on the DU in Figures 2A and 2B and partially deployed on the CU. For another example, the transceiver unit 720 and the processing unit 710 can both be deployed on the DU in Figure 2D.

[0205] A more detailed description of the processing unit 710 and the transceiver unit 720 can be directly obtained by referring to the relevant description in the method embodiment shown in FIG5 , and is not repeated here.

[0206] When the communication device is a chip used in a terminal device, the terminal device chip implements the functions of the terminal device in the above method embodiments. The terminal device chip receives information from other modules in the terminal device (such as a radio frequency module or antenna), and the information is sent by the network device to the terminal device; or the terminal device chip sends information to other modules in the terminal device (such as a radio frequency module or antenna), and the information is sent by the terminal device to the network device.

[0207] When the communication device is a chip used in a network device, the network device chip implements the network device functions of the above method embodiments. The network device chip receives information from other modules in the network device (such as a radio frequency module or antenna), and the information is sent by the terminal device to the network device; or the network device chip sends information to other modules in the network device (such as a radio frequency module or antenna), and the information is sent by the network device to the terminal device.

[0208] In addition, it should be noted that the aforementioned transceiver unit and / or processing unit may be implemented through virtual modules, for example, the processing unit may be implemented through a software function unit or a virtual device, and the transceiver unit may be implemented through a software function or a virtual device. Alternatively, the processing unit or transceiver unit may also be implemented through a physical device, for example, if the device is implemented using a chip / chip circuit, the transceiver unit may be an input / output circuit and / or a communication interface, performing input operations (corresponding to the aforementioned receiving operations) and output operations (corresponding to the aforementioned sending operations); the processing unit may be an integrated processor, microprocessor, or integrated circuit.

[0209] As shown in Figure 8, the communication device 800 includes a processor 810 and may also include an interface circuit 820. The processor 810 and the interface circuit 820 are coupled to each other. It will be understood that the interface circuit 820 may be a transceiver or an input / output interface. Optionally, the communication device 800 may also include a memory 830 (indicated by a dotted line in the figure) for storing instructions executed by the processor 810, or storing input data required by the processor 810 to execute instructions, or storing data generated after the processor 810 executes instructions.

[0210] When the communication apparatus 800 is used to implement the functions of the terminal device in the method embodiment shown in FIG5 : the interface circuit 820 is used to implement the functions of the terminal device in steps S501 to S503 in the embodiment shown in FIG5 .

[0211] When the communication device 800 is used to implement the functions of the network device in the method embodiment shown in Figure 5: the interface circuit 820 is used to implement the functions of the network device in steps S501 to S503 in the embodiment shown in Figure 5, and the processor 810 is used to implement step S504 in the embodiment shown in Figure 5.

[0212] A more detailed description of the processor 810 and the interface circuit 820 can be directly obtained by referring to the relevant description in the method embodiment shown in FIG5 , and is not repeated here.

[0213] The division of modules in this application is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the examples of this application may be integrated into a single processor, exist physically as separate modules, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in either hardware or software functional modules.

[0214] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0215] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program or instruction is stored. When the computer program or instruction is executed, the method in the above embodiment is implemented.

[0216] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method in the above embodiment.

[0217] An embodiment of the present application also provides a communication system, including the above-mentioned communication device.

[0218] The present application also provides a circuit, which is coupled to a memory and is used to execute the method shown in the above embodiment. The circuit may include a chip circuit.

[0219] When the above-mentioned communication device is a module applied to a network device, the network device module implements the functions of the network device in the above-mentioned method embodiment. The network device module receives information from other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the UE to the network device; or, the network device module sends information to other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the network device to the UE. The network device module here can be a baseband chip of the network device, or a CU, DU or other module, or a device under the open radio access network (O-RAN) architecture, such as an open CU, open DU and other devices.

[0220] It should be noted that the above units or one or more of the units can be implemented by software, hardware, or a combination of the two. When any of the above units or units is implemented by software, the software exists in the form of computer program instructions and is stored in a memory, and a processor can be used to execute the program instructions and implement the above method flow.

[0221] In this application, a processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or all or part of the circuitry in the aforementioned devices used to implement processing functions, which may implement or execute the various methods, steps, and logic block diagrams disclosed in this application. A general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the methods disclosed in this application may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0222] When the above units or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a digital signal processing (DSP) chip, a microcontroller unit (MCU), an artificial intelligence processor, an ASIC, a SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator or a non-integrated discrete device, which can run the necessary software or not rely on the software to execute the above method flow.

[0223] Optionally, an embodiment of the present application further provides a chip system, comprising: at least one processor and an interface, wherein the at least one processor is coupled to a memory via the interface, and when the at least one processor executes a computer program or instruction in the memory, the chip system executes the method in any of the above method embodiments. Optionally, the chip system may be composed of a chip, or may include a chip and other discrete devices, which is not specifically limited in the embodiments of the present application.

[0224] The memory in the present application may also be a circuit or any other device capable of implementing a storage function for storing program instructions and / or data. A memory is any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto. For example, the memory may be a non-volatile memory, such as a digital versatile disc (DVD), a hard disk drive (HDD), or a solid-state drive (SSD), or a volatile memory, such as a random-access memory (RAM).

[0225] It should be understood that in the description of this application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship. For example, A / B can mean A or B; where A and B can be singular or plural. Also, in the description of this application, unless otherwise specified, "multiple" means two or more than two. "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. In addition, to facilitate the clear description of the technical solutions of the embodiments of this application, in the embodiments of this application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity or execution order, and words such as "first" and "second" do not necessarily mean different. At the same time, in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0226] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it 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. When the computer program instructions are loaded and 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 wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0227] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art can understand and implement other changes to the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0228] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

[0229] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0230] The components in the device of the embodiment of the present application can be merged, divided, or deleted according to actual needs. Those skilled in the art can combine or combine the different embodiments and features of the different embodiments described in this specification.

[0231] In this application, under the premise of no logical contradiction, the examples can reference each other, for example, the methods and / or terms between method embodiments can reference each other, for example, the functions and / or terms between device embodiments can reference each other, for example, the functions and / or terms between device examples and method examples can reference each other.

Claims

1. A method for reporting channel state information, characterized in that The method includes: Receiving a first reference signal; Based on the first reference signal, sending first information, the first information including indication information of at least one first spatial domain basis vector corresponding to a first precoding matrix, the first precoding matrix being obtained based on the at least one first spatial domain basis vector and at least one second spatial domain basis vector, the at least one second spatial domain basis vector being obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1.

2. The method according to claim 1, wherein Before receiving the first reference signal, the method further includes: Receiving the second reference signal n times; Based on the second reference signals received n times, respectively sending indication information of the n second precoding matrices.

3. The method according to claim 1 or 2, characterized in that The at least one second spatial domain basis vector is obtained based on precoding vectors corresponding to X transmission layers of a first frequency domain unit among the n second precoding matrices.

4. The method according to claim 3, wherein When n = 1, X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

5. The method according to claim 3, characterized in that When n is greater than 1, the at least one second spatial domain basis vector is obtained based on the average value of precoding vectors corresponding to X transmission layers of a first frequency domain unit among the n second precoding matrices.

6. The method according to claim 3, wherein When n is greater than 1, the at least one second spatial domain basis vector is obtained based on the singular value decomposition values of the covariance matrix obtained based on precoding vectors corresponding to X transmission layers of a first frequency domain unit among the n second precoding matrices.

7. The method according to claim 5 or 6, characterized in that X is less than or equal to the minimum value of the numbers of transmission layers corresponding to the n second precoding matrices respectively.

8. The method according to any one of claims 3-7, characterized in that, The first frequency domain unit is the same k frequency domain units corresponding to the n second precoding matrices, and each of the n second precoding matrices corresponds to K frequency domain units, where 1 ≤ k ≤ K.

9. The method according to any one of claims 1-8, characterized in that, The first precoding matrix is obtained based on the at least one first spatial domain basis vector and at least one second spatial domain basis vector, including: The first precoding matrix is obtained based on the orthogonality result of the at least one first spatial domain basis vector and at least one second spatial domain basis vector.

10. A method for reporting channel state information, characterized in that, The method includes: Sending a first reference signal; Receiving first information, the first information including indication information of at least one first spatial domain basis vector corresponding to a first precoding matrix, the first precoding matrix being obtained based on the at least one first spatial domain basis vector and at least one second spatial domain basis vector, the at least one second spatial domain basis vector being obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1; Obtaining the first precoding matrix based on the first information.

11. The method according to claim 10, wherein Before sending the first reference signal, the method further includes: Sending the second reference signal n times; Based on the second reference signals sent n times, respectively receiving indication information of the n second precoding matrices.

12. The method according to claim 10 or 11, characterized in that, The at least one second spatial domain basis vector is obtained based on precoding vectors corresponding to X transmission layers of a first frequency domain unit among the n second precoding matrices.

13. The method according to claim 12, wherein When n = 1, X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

14. The method according to claim 12, wherein n is greater than 1, and the at least one second spatial domain basis vector is obtained based on the average value of the precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

15. The method according to claim 12, wherein n is greater than 1, and the at least one second spatial domain basis vector is obtained based on the singular value decomposition values of the covariance matrix obtained from the precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

16. The method according to claim 14 or 15, characterized in that, X is less than or equal to the minimum value among the numbers of transmission layers corresponding to the n second precoding matrices respectively.

17. The method according to any one of claims 12-16, characterized in that, The first frequency domain unit is the same k frequency domain units corresponding to the n second precoding matrices, and each of the n second precoding matrices corresponds to K frequency domain units, where 1 ≤ k ≤ K.

18. The method according to any one of claims 10-17, characterized in that, The first precoding matrix is obtained based on the at least one first spatial domain basis vector and the at least one second spatial domain basis vector, including: The first precoding matrix is obtained based on the orthonormalization result of the at least one first spatial domain basis vector and the at least one second spatial domain basis vector.

19. The method according to any one of claims 11-18, characterized in that, Obtaining the first precoding matrix based on the first information includes: Obtaining the at least one second spatial domain basis vector based on the indication information of the n second precoding matrices; Obtaining the first precoding matrix based on the at least one first spatial domain basis vector and the at least one second spatial domain basis vector.

20. A communication device, characterized in that, The apparatus includes: a transceiver unit and a processing unit; wherein: The transceiver unit is configured to receive a first reference signal; The processing unit is configured to generate first information based on the first reference signal, where the first information includes indication information of at least one first spatial domain basis vector corresponding to a first precoding matrix, the first precoding matrix is obtained based on the at least one first spatial domain basis vector and the at least one second spatial domain basis vector, the at least one second spatial domain basis vector is obtained based on n second precoding matrices, and n is a positive integer greater than or equal to 1; The transceiver unit is further configured to send the first information.

21. The device according to claim 20, characterized in that, Before receiving the first reference signal, the transceiver unit further receives the second reference signal n times; and the transceiver unit is further configured to send the indication information of the n second precoding matrices respectively based on the n received second reference signals.

22. The device according to claim 20 or 21, characterized in that, The at least one second spatial domain basis vector is obtained based on the precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

23. The device according to claim 22, characterized in that, n = 1, and X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

24. The device according to claim 22, characterized in that, n is greater than 1, and the at least one second spatial domain basis vector is obtained based on the average value of the precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

25. The device according to claim 22, characterized in that, n is greater than 1, and the at least one second spatial domain basis vector is obtained based on the singular value decomposition values of the covariance matrix obtained from the precoding vectors corresponding to X transmission layers of the first frequency domain unit in the n second precoding matrices.

26. The device according to claim 24 or 25, characterized in that, X is less than or equal to the minimum value among the numbers of transmission layers corresponding to the n second precoding matrices respectively.

27. The device according to any one of claims 22-26, characterized in that, The first frequency-domain unit is the same k frequency-domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponding to K frequency-domain units, where 1 ≤ k ≤ K.

28. The device according to any one of claims 20-27, characterized in that, The first precoding matrix is obtained based on the at least one first spatial-domain basis vector and at least one second spatial-domain basis vector, including: The first precoding matrix is obtained based on the orthonormalization result of the at least one first spatial-domain basis vector and at least one second spatial-domain basis vector.

29. A communication device, characterized in that, The apparatus includes: a transceiver unit and a processing unit; wherein: The transceiver unit is configured to send a first reference signal. The transceiver unit is further configured to receive first information, the first information including indication information of at least one first spatial-domain basis vector corresponding to a first precoding matrix, the first precoding matrix being obtained based on the at least one first spatial-domain basis vector and at least one second spatial-domain basis vector, the at least one second spatial-domain basis vector being obtained based on n second precoding matrices, where n is a positive integer greater than or equal to 1. The processing unit is configured to obtain the first precoding matrix based on the first information.

30. The device according to claim 29, characterized in that, The transceiver unit is further configured to send a second reference signal n times before sending the first reference signal; and the transceiver unit is further configured to receive indication information of the n second precoding matrices respectively based on the n times of sending the second reference signal.

31. The device according to claim 29 or 30, characterized in that, The at least one second spatial-domain basis vector is obtained based on precoding vectors corresponding to X transmission layers of a first frequency-domain unit in the n second precoding matrices.

32. The device according to claim 31, wherein When n = 1, X is less than or equal to the number of transmission layers corresponding to the second precoding matrix.

33. The device according to claim 31, characterized in that, When n > 1, the at least one second spatial-domain basis vector is obtained based on the average value of precoding vectors corresponding to X transmission layers of a first frequency-domain unit in the n second precoding matrices.

34. The device according to claim 31, characterized in that, When n > 1, the at least one second spatial-domain basis vector is obtained based on the singular value decomposition values of the covariance matrix obtained from precoding vectors corresponding to X transmission layers of a first frequency-domain unit in the n second precoding matrices.

35. The device according to claim 33 or 34, characterized in that, X is less than or equal to the minimum value of the numbers of transmission layers corresponding to the n second precoding matrices respectively.

36. The device according to any one of claims 31 to 35, characterized in that, The first frequency-domain unit is the same k frequency-domain units corresponding to the n second precoding matrices, each of the n second precoding matrices corresponding to K frequency-domain units, where 1 ≤ k ≤ K.

37. The device according to any one of claims 29-36, characterized in that, The first precoding matrix is obtained based on the at least one first spatial-domain basis vector and at least one second spatial-domain basis vector, including: The first precoding matrix is obtained based on the orthonormalization result of the at least one first spatial-domain basis vector and at least one second spatial-domain basis vector.

38. The apparatus according to any one of claims 29-37, wherein: The processing unit is further configured to obtain the at least one second spatial-domain basis vector based on the indication information of the n second precoding matrices. The processing unit is further configured to obtain the first precoding matrix based on the at least one first spatial-domain basis vector and the at least one second spatial-domain basis vector.

39. A communication system, characterized in that, The system includes a first communication device and a second communication device. The first communication device is configured to implement the method according to any one of claims 1-9, and the second communication device is configured to implement the method according to any one of claims 10-19.

40. A communication device, characterized in that, It includes a processor and an interface circuit. The interface circuit is configured to receive signals from other communication devices outside the communication device and transmit them to the processor, or send signals from the processor to other communication devices outside the communication device. The processor is configured to implement the method according to any one of claims 1-9 or the method according to any one of claims 10-19 through logic circuits or by executing code instructions.

41. The communication device according to claim 40, wherein, The communication device is a chip.

42. A chip module, characterized in that, It includes a transceiver component and a chip. The chip is configured to execute the method according to any one of claims 1-9 or the method according to any one of claims 10-19.

43. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method according to any one of claims 1-9 or the method according to any one of claims 10-19.

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