Communication method, device and system, chip, chip module and storage medium

Abstract

The invention discloses a communication method, device and system, a chip, a chip module and a storage medium. A network device pairs a plurality of terminals according to weight vectors corresponding to main transmission directions of the plurality of terminals, configures a group of shared reference signal weight matrixes for paired terminals, and sends reference signals to the paired terminals at a reference signal port group at a plurality of moments based on the reference signal weight matrixes. The channel measurement of the NTN network can be realized, and the robustness of the channel measurement is improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method, device, system, chip, chip module and storage medium. Background Art

[0002] Non-terrestrial networks (NTN) can serve multiple terminals simultaneously, and the satellites move fast, the transmission delay is large, and the satellite channel has significant time-varying phenomenon.

[0003] In the new radio (NR) ground system, the base station obtains channel information by sending a channel state information-reference signal (CSI-RS) to the terminal. The terminal performs channel measurement based on the CSI-RS and feeds back a precoding matrix indicator (PMI) that matches the channel state to the base station. However, the PMI feedback in the NR scenario is mainly designed for single-user channels and does not involve channel feedback in multi-user scenarios. In addition, the PMI feedback in the NR scenario is mainly based on the assumption of dual-polarized antennas at the base station end, but in the NTN scenario, satellites generally use left-handed or right-handed single polarization, so the NR codebook is not suitable for the NTN scenario. And because the satellite moves quickly and has a large transmission delay, the NR weight feedback lacks robustness when applied to the NTN scenario.

[0004] In order to improve resource utilization, satellite system beams generally use space division multiplexing. The interference between beams will gradually become more significant as the number of users increases, and the number of beams that meet the inter-beam isolation requirements in the space division beam group will also be limited, resulting in the overall capacity of the satellite being limited and unable to grow linearly with the number of beams.

[0005] Therefore, in the NTN scenario, how to perform channel measurement and improve the robustness of channel measurement is an urgent problem to be solved. Summary of the invention

[0006] The present application provides a communication method, device, system, chip, chip module and storage medium to implement channel measurement of an NTN network and improve the robustness of the channel measurement.

[0007] In a first aspect, a communication method is provided. The method can be implemented by a first terminal or a chip or circuit used for the first terminal.

[0008] The method includes: receiving reference signals at the reference signal port group at multiple times according to the reference signal weight matrix corresponding to the reference signal port group, wherein the first terminal belongs to any one of the K terminals, and according to the weight vectors corresponding to the main transmission directions of the K terminals, the K terminals are divided into the same group, and the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2, and the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and less than or equal to K. By adopting this method, the channel measurement of the NTN network can be realized, and the robustness of the channel measurement can be improved; the scheduling terminal is paired in advance through the network equipment, and the form of the reference signal weight matrix is ​​designed for the paired terminal, so that the terminal can simultaneously measure its own target channel state and the interference channel state of other terminals.

[0009] In combination with the first aspect, in a possible implementation, the method further includes: sending a channel measurement result, wherein the channel measurement result is based on a statistical average of equivalent channels at the multiple moments, wherein the equivalent channel is a channel estimated based on the reference signal. With this implementation, the terminal performs statistical averaging on the reference signal receiving channel at multiple moments and calculates the covariance matrix, so that the network device can design more robust and high-capacity low-interference transmission weights for multiple terminals.

[0010] In a second aspect, a communication method is provided, which can be implemented by a network device or a chip or circuit used for a network device.

[0011] The method includes: dividing the K terminals into the same group according to the weight vectors corresponding to the main transmission directions of the K terminals, wherein the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2; obtaining the reference signal weight matrix corresponding to the reference signal port group, wherein the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and less than or equal to K; and the network device sends reference signals to the K terminals at the reference signal port group at multiple times according to the reference signal weight matrix. By adopting this method, channel measurement of the NTN network can be realized and the robustness of channel measurement can be improved.

[0012] In combination with the second aspect, in a possible implementation, the method further includes: receiving channel measurement results from the K terminals.

[0013] In combination with the first aspect or the second aspect, in another possible implementation, the correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or the isolation of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or the interval of the transmission angles of the main transmission directions of the K terminals is greater than or equal to a third threshold.

[0014] In combination with the first aspect or the second aspect, in another possible implementation, the equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and the array steering vector corresponding to the transmission direction, and the first parameter remains unchanged during the multiple moments.

[0015] In combination with the first aspect or the second aspect, in another possible implementation, the statistical average is a covariance matrix, and the channel measurement result includes the amplitude and phase of multiple elements in the covariance matrix, and the amplitude of the multiple elements is greater than or equal to a fourth threshold. With this implementation, the terminal performs statistical averaging on the reference signal receiving channel at multiple times, calculates the covariance matrix, and feeds back some elements with higher amplitudes in the covariance matrix, so that the base station can simultaneously obtain the transmission direction and directional weight of the target channel and the interference channel at a lower feedback overhead, which is convenient for the satellite to design more robust and low-interference transmission weights of multiple terminals with better capacity.

[0016] In combination with the first aspect or the second aspect, in another possible implementation, the statistical average is a covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein the l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix. With this implementation, the terminal performs statistical averaging on the CSI-RS receiving channel at multiple times, calculates the covariance matrix, and feeds back the first several columns of the unitary matrix after the characteristic decomposition of the covariance matrix. In the case of maximizing the reuse of the NR standard design, the network equipment is enabled to simultaneously obtain the transmission direction of the target channel and the interference channel, so that the satellite can design more robust multi-terminal low-interference transmission weights, thereby improving the single-satellite capacity compared to traditional satellite solutions.

[0017] In a third aspect, a communication device is provided for implementing the communication method in the first aspect or any one of the implementations of the first aspect. The device may be a terminal, or a module applied to a terminal (such as a processor, a chip, or a chip system, etc.), or a logical node, a logical module, or software that can implement all or part of the terminal functions. In one implementation, the communication device may include a sending unit, a receiving unit, and may also include a processing unit. The sending unit and the receiving unit may be independent or combined together (which may be referred to as a "transceiver unit").

[0018] In a possible implementation manner, the communication device includes a module for respectively executing the method in the above-mentioned first aspect or any one of the implementations of the first aspect.

[0019] The transceiver unit is used to receive reference signals at the reference signal port group at multiple times according to the reference signal weight matrix corresponding to the reference signal port group, wherein the first terminal belongs to any one of the K terminals, and according to the weight vectors corresponding to the main transmission directions of the K terminals, the K terminals are divided into the same group, and the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2. The reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and is less than or equal to K.

[0020] Optionally, the transceiver unit is further used to send a channel measurement result, where the channel measurement result is based on a statistical average of equivalent channels at the multiple time moments, and the equivalent channel is a channel estimated based on the reference signal.

[0021] In a fourth aspect, a communication device is provided for implementing the communication method in the second aspect or any one of the implementations of the second aspect. The device may be a network device, or a module (such as a processor, a chip, or a chip system, etc.) applied to a network device, or a logical node, a logical module, or software that can implement all or part of the functions of a network device. In one implementation, the communication device may include a sending unit, a receiving unit, and may also include a processing unit. The sending unit and the receiving unit may be independent or combined together (which may be referred to as a "transceiver unit").

[0022] In a possible implementation manner, the communication device includes a module for respectively executing the method in the above-mentioned second aspect or any one of the implementations of the second aspect.

[0023] The processing unit is used to divide the K terminals into the same group according to the weight vectors corresponding to the main transmission directions of the K terminals, wherein the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2; the processing unit is also used to obtain a reference signal weight matrix corresponding to the reference signal port group, wherein the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and less than or equal to K; and the transceiver unit is used to send reference signals to the K terminals in the reference signal port group at multiple times according to the reference signal weight matrix.

[0024] Optionally, the transceiver unit is further used to receive channel measurement results from the K terminals.

[0025] In combination with the third aspect or the fourth aspect, in an example, the correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or the isolation of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or the interval of the transmission angles of the main transmission directions of the K terminals is greater than or equal to a third threshold.

[0026] In combination with the third aspect or the fourth aspect, in another example, the equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and the array steering vector corresponding to the transmission direction, and the first parameter remains unchanged during the multiple moments.

[0027] In combination with the third aspect or the fourth aspect, in yet another example, the statistical average is a covariance matrix, the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

[0028] In combination with the third aspect or the fourth aspect, in another example, the statistical average is a covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

[0029] In another possible implementation, the communication device in the third aspect to the fourth aspect includes a processor coupled to a memory; the processor is configured to enable the device to perform the corresponding functions in the above communication method. The memory is used to couple with the processor, which stores the necessary programs (instructions) and / or data for the device. Optionally, the communication device may also include a communication interface for implementing communication between the device and other network elements. Optionally, the memory may be located inside the communication device or outside the communication device.

[0030] In another possible implementation, the communication device in the third to fourth aspects includes a processor and a transceiver, the processor is coupled to the transceiver, and the processor is 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 execute code instructions. The transceiver may be a transceiver, a transceiver circuit or an input-output interface, which is used to receive signals from other communication devices other than the communication device and transmit them to the processor or 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.

[0031] When the communication device in the third to fourth aspects 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, the sending unit may be a transmitter or a transmitter; the receiving unit may be a receiver or a receiver.

[0032] In a fifth aspect, a computer-readable storage medium is provided, in which a computer program or instruction is stored. When the computer program or instruction is executed, the methods described in the above aspects are implemented.

[0033] According to a sixth aspect, a computer program product comprising instructions is provided. When the instructions are executed on a communication device, the communication device executes the methods described in the above aspects.

[0034] In a seventh aspect, a communication system is provided, which includes the communication device described in the third aspect and the communication device described in the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A simplified schematic diagram of a wireless communication system provided by an embodiment of the present application;

[0036] Figure 2A The schematic diagram of NTN scenario based on transparent load;

[0037] Figure 2B Schematic diagram of NTN scenario based on regenerative load;

[0038] Figure 3 It is a schematic diagram of communication between a satellite base station and a terminal;

[0039] Figure 4 This is a schematic diagram of satellite channels;

[0040] Figure 5 A schematic diagram of the flow chart for designing transmission weights for multiple terminals in the ground system;

[0041] Figure 6 It is a schematic diagram of frequency division multiplexing;

[0042] Figure 7 A flow chart of a communication method provided in an embodiment of the present application;

[0043] Figure 8 A schematic diagram for pairing terminals;

[0044] Fig. 9 A schematic diagram of the interaction flow between a network device and a terminal over time provided in an embodiment of the present application;

[0045] Fig.10 A schematic diagram of a process of performing terminal pairing based on angle prior information according to an embodiment of the present application;

[0046] Fig.11 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0047] Fig.12 A schematic diagram of the structure of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0049] The at least one (item) involved in the present application as follows indicates one (item) or more (items). More than one (item) refers to two (items) or more than two (items). "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. In addition, it should be understood that although the terms first, second, etc. may be used to describe each object in the present application, these objects should not be limited to these terms. These terms are only used to distinguish each object from each other.

[0050] The terms "including" and "having" and any variations thereof mentioned in the following description of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes other steps or units that are not listed, or optionally includes other steps or units that are inherent to these processes, methods, products or devices. It should be noted that in the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any method or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other methods or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way.

[0051] The technology provided by the present application can be applied to various communication systems. For example, the communication system can be a fourth generation (4 th generation, 4G) communication systems (such as long term evolution (LTE) systems), fifth generation (5 th The 5G communication system may also be referred to as a new radio (NR) system.

[0052] A network element in a communication system can send a signal to another network element or receive a signal from another network element. The signal may include information, signaling, or data, etc. The network element may also be replaced by an entity, a network entity, a device, a terminal, a communication module, a node, a communication node, etc. The network element is used as an example for description in this application. For example, a communication system may include at least one terminal and at least one access network device. The access network device may send a downlink signal to the terminal, and / or the terminal may send an uplink signal to the access network device. In addition, it can be understood that if a plurality of terminals are included in the communication system, the plurality of terminals may also send signals to each other, that is, the signal sending network element and the signal receiving network element may both be terminals.

[0053] The communication method provided in the embodiment of the present application can be applied to wireless communication systems such as 5G, 6G, satellite communication, etc. Figure 1 , Figure 1 A simplified schematic diagram of a wireless communication system provided in an embodiment of the present application. Figure 1As shown, the wireless communication system includes a wireless access network 100. The wireless access network 100 may be a next generation (e.g., 6G or higher) wireless access network, or a traditional (e.g., 5G, 4G) wireless access network. One or more terminals (120a-120g, collectively referred to as 120) may be connected to each other, or to one or more network devices (110a-110c, collectively referred to as 110) in the wireless access network 100, and the connection mode may be wired or wireless. Optionally, Figure 1 This is just a schematic diagram. The wireless communication system may also include other devices, such as core network devices, wireless relay devices and / or wireless backhaul devices. Figure 1 Not drawn in.

[0054] Optionally, in practical applications, the wireless communication system may include multiple network devices (also referred to as access network devices) at the same time, and may also include multiple terminals at the same time. A network device may serve one or more terminals at the same time. A terminal may also access one or more network devices at the same time. The embodiment of the present application does not limit the number of terminals and network devices included in the wireless communication system.

[0055] 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 to access the wireless communication system in a wireless manner, such as a base station. The base station can broadly cover the following various names, or be replaced with the following names, such as: 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 (transmitting and receiving point, TRP), transmission point (transmitting point, TP), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), centralized unit (CU), distributed unit (DU), radio unit (RU), centralized unit control plane (CU The base station may be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The network device may also refer to a communication module, a modem or a chip that is arranged in the aforementioned device or apparatus. The network device may also be a mobile switching center and a device that performs the base station function in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, a network side device in a 6G network, and a device that performs the base station function 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.

[0056] The network equipment may be fixed or mobile. For example, base stations 110 b and 110 c are stationary and are responsible for wireless transmission and reception in one or more cells from terminal 120 . Figure 1 The helicopter or drone 120c shown in the figure 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 120c. In other examples, the helicopter or drone (120c) can be configured to be used as a terminal for communicating with the satellite base station 110a.

[0057] In the present application, the communication device used to implement the above access network function can be an access network device, or a network device with some functions of accessing the network, 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 plus a software module, which can be installed in the access network device or used in combination with the access network device. In the method of the present application, the communication device used to implement the access network device function is an access network device for example.

[0058] The terminal can be an entity on the user side for receiving or transmitting signals, such as a mobile phone. The terminal can be used to connect people, objects and machines. The terminal can communicate with one or more core networks through network devices. The terminal includes a handheld device with a wireless connection function, other processing devices connected to a wireless modem, or a vehicle-mounted device. The terminal can be a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device. The terminal 120 can 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 wear, smart transportation, smart city, drone, robot, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery and mobility, etc.Some examples of the terminal 120 are: user equipment (UE) of 3GPP standard, fixed equipment, mobile equipment, handheld equipment, wearable equipment, cellular phone, smart phone, session initiated protocol (SIP) phone, laptop computer, personal computer, smart book, vehicle, satellite, global positioning system (GPS) equipment, target tracking equipment, drone, helicopter, aircraft, ship, remote control equipment, smart home equipment, industrial equipment, personal communication service (PCS) phone, wireless local loop (WLL) station, personal digital assistant (PDA), wireless network camera, tablet computer, PDA, mobile internet device (MID), wearable equipment such as smart watch, VR equipment, AR equipment, wireless terminal in industrial control, terminal in vehicle networking system, wireless terminal in self driving, wireless terminal in smart grid, wireless terminal in transportation safety, smart city, etc. The terminal 120 may be a wireless terminal in a smart city, such as a smart gas pump, a terminal on a high-speed rail, and a wireless terminal in a smart home, such as a smart speaker, a smart coffee machine, a smart printer, etc. The terminal 120 may be a wireless device in the above various scenarios or a device used to be set in a wireless device, for example, a communication module, a modem or a chip in the above device. The terminal may also be referred to as a terminal device, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc. The terminal may also be a terminal in a future wireless communication system. The terminal 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.

[0059] Optionally, the terminal may be used to act as a base station. For example, the UE may act as a scheduling entity that provides sidelink signals between UEs in V2X, D2D, or P2P, etc. Figure 1 As shown, the cell phone 120a and the car 120b communicate with each other using a sidelink signal. The cell phone 120a and the smart home device 120e communicate with each other without relaying the communication signal through the base station 110b.

[0060] In the present application, the communication device for realizing the terminal function may be a terminal, or a terminal having some functions of the above terminal, or a device capable of supporting the realization of the functions of the above terminal, such as a chip system, which may be installed in the terminal or used in combination with the terminal. In the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices. In the technical solution provided in the present application, the communication device is described as a terminal or UE as an example.

[0061] Optionally, a wireless communication system is usually composed of cells, and the base station provides management of the cell. The base station provides 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 places, for example: the RRU is remote and placed in an area with high traffic volume, and 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 one rack. Optionally, a cell can correspond to a carrier or a component carrier.

[0062] In some deployments, the network device mentioned in the embodiments of the present application may be a device including a CU, or a DU, or a device including a CU and a DU, or a control plane CU node (central unit control plane (central unit-control plane, CU-CP)) and a user plane CU node (central unit user plane (central unit-user plane, CU-UP)) and a DU node. For example, the network device may include a gNB-CU-CP, a gNB-CU-UP, and a gNB-DU.

[0063] In some deployments, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes implement part of the functions of the base station. For example, the RAN node can be a CU, DU, CU-CP, CU-UP, or RU. The CU and DU can be set separately, or can also be included in the same network element, such as a BBU. The RU can be included in a radio frequency device or a radio frequency unit, such as an RRU, AAU, or RRH.

[0064] The RAN node may support one or more types of fronthaul interfaces, and different fronthaul interfaces correspond 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 interface, relative to the CPRI, part of the downlink and / or uplink baseband functions, such as, for downlink, one or more of precoding, digital beamforming (BF), or inverse fast Fourier transform (IFFT) / adding cyclic prefix (CP), 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) / removing cyclic prefix (CP), are moved from the DU to the RU for implementation. In a possible implementation, the interface may be an enhanced common public radio interface (eCPRI). In the eCPRI architecture, the division between DU and RU is different, corresponding to different types (category, Cat) of eCPRI, such as eCPRI Cat A, B, C, D, E, F.

[0065] 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 before it (i.e., one or more functions of coding, rate matching, scrambling, modulation, and layer mapping), while other functions after layer mapping (e.g., RE mapping, digital beamforming (BF), or one or more functions of inverse fast Fourier transform (IFFT) / adding cyclic prefix (CP)) are moved to the RU for implementation. For uplink transmission, based on de-RE mapping, the DU is configured to implement de-mapping and one or more functions before it (i.e., one or more functions of decoding, de-rate matching, de-scrambling, demodulation, inverse discrete Fourier transform (IDFT), channel equalization, and de-RE mapping), while other functions after de-mapping (e.g., one or more functions of digital BF or fast Fourier transform (FFT) / removing CP) are moved to the RU for implementation. It can be understood that for the functional description of DU and RU corresponding to various types of eCPRI, reference can be made to the eCPRI protocol and will not be repeated here.

[0066] In one possible design, the processing unit for implementing the baseband function in the BBU is called a baseband high layer (BBH) unit, and the processing unit for implementing the baseband function in the RRU / AAU / RRH is called a baseband low layer (BBL) unit.

[0067] 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 in the CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0068] In the embodiments of the present application, the device for realizing the function of the network device may be a network device; or it may be a device capable of supporting the network device to realize the function, such as a chip system, a hardware circuit, a software module, or a hardware circuit plus a software module. The device may be installed in the network device or used in combination with the network device. In the embodiments of the present application, only the device for realizing the function of the network device is a network device as an example for explanation, and the scheme of the embodiments of the present application is not limited.

[0069] It can be understood that the present application can be applied between network devices and terminals.

[0070] The communication between the network device and the terminal 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 protocol layers such as 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 protocol layers such as the PDCP layer, the RLC layer, the MAC layer and the physical layer. In a possible implementation, the service data adaptation protocol (SDAP) layer may also be included above the PDCP layer.

[0071] Optionally, the protocol layer structure between the network device and the terminal may also include an artificial intelligence (AI) layer for transmitting data related to AI functions.

[0072] Taking data transmission between network devices and terminals as an example, data transmission needs to pass through the user plane protocol layer, such as the SDAP layer, PDCP layer, RLC layer, MAC layer, and physical layer. Among them, the SDAP layer, PDCP layer, RLC layer, MAC layer, and physical layer can also be collectively referred to as the access layer. According to the transmission direction of the data, it is divided into sending or receiving, and each of the above layers is 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 the MAC layer, and then the MAC layer generates a transmission block, and then transmits it wirelessly through the physical layer. The data is encapsulated accordingly in each layer. For example, the data received by a layer from the upper layer of the layer is regarded as the service data unit (SDU) of the layer, which becomes a protocol data unit (PDU) after being encapsulated by the layer, and then passed to the next layer.

[0073] Exemplarily, the terminal may also have an application layer and a non-access layer. The application layer may be used to provide services to applications installed in the terminal. For example, downlink data received by the terminal may be sequentially transmitted from the physical layer to the application layer, and then provided to the application by the application layer; for another example, the application layer may obtain data generated by the application, and sequentially transmit the data to the physical layer and send it to other communication devices. The non-access layer may 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.

[0074] It should be understood that Figure 1 The number and type of each device in the communication system shown are for illustration only, and the present application is not limited thereto. In actual applications, the communication system may also include more terminals, more access network devices, and other network elements, such as core network devices, and / or network elements for implementing artificial intelligence functions.

[0075] It is understandable that all or part of the functions implemented by one or more of the terminals, access network devices, core network devices, or network elements used to implement 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 and the access network device involve the interface of air interface transmission, the transceiver function of the interface 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, access network equipment, core network equipment, or network elements used to implement artificial intelligence functions can be implemented by cloud devices, such as cloud devices in over the top (OTT) systems.

[0076] The following first introduces the NTN network involved in this application:

[0077] NTN refers to a network that uses radio frequency resources on satellite platforms (including low earth orbit (LEO), medium earth orbit (MEO), geostationary earth orbit (GEO)), unmanned aerial vehicle (UAV) platforms, or HAPS platforms to provide communication services. th Compared with the terrestrial network (5G) and 5G mobile communications), the NTN network has the characteristics of wide coverage, low latency, broadband and low cost. As a supplement and extension of the ground network, the NTN network can achieve wide-area seamless coverage that neither the wired telephone network nor the ground mobile communication network can achieve, effectively solving the problem of Internet access in areas with insufficient communication infrastructure. A large number of satellites are deployed in low-Earth orbit, and the round-trip transmission delay of data between satellites and ground terminals is greatly reduced, reaching a low latency of tens of milliseconds. The use of technologies such as high-frequency bands, multi-spot beams and frequency reuse has significantly improved the communication capabilities of satellites, reduced the unit broadband cost, and can meet the needs of high-information rate services. Compared with communication infrastructure such as ground 5G base stations and submarine optical fiber cables, NTN has significant cost advantages. Modern small satellites have low R&D and manufacturing costs, and software-defined technology can further extend the service life of satellites in orbit. The NTN network can be used in scenarios such as global coverage (such as remote areas, ocean-going ships, etc.), emergency rescue (such as disaster monitoring, emergency communications), the Internet of Everything, and high-speed mobility (such as high-speed rail and airplanes).

[0078] Typical scenarios for NTN network to provide terminal access include transparent payload and regenerative payload. Figure 2A The NTN scenario diagram based on transparent load is shown in the figure. The transparent load is a load that changes the frequency carrier of the uplink RF signal and filters and amplifies it before downlink transmission. This load only has a RF processing unit and no baseband demodulation, decoding and other processing. Therefore, the signal waveform is unchanged and is repeated. Figure 2B The schematic diagram of the NTN scenario based on the regenerative load shown is a load that transforms and amplifies the uplink radio frequency (RF) signal before downlink transmission. The signal transformation refers to digital processing, which may include demodulation, decoding, re-encoding, re-modulation and / or filtering. This is actually equivalent to having all or part of the base station functions on the satellite (or UAS platform).

[0079] The above-mentioned NTN network usually has the following elements:

[0080] (1) There are one or more gateways connecting the NTN network and the common data network.

[0081] (2) Feeder link: The wireless link between the gateway and the satellite (or UAS platform).

[0082] (3) Service link: The wireless link between the terminal and the satellite (or UAS platform).

[0083] (4) Satellites (or UAS platforms) can realize transparent payloads and regenerative payloads.

[0084] (5) Whether the satellite constellation has an inter-satellite link (ISL) is optional. An ISL requires the satellite to be a regenerative payload (i.e., if there is an ISL, the satellite must be a regenerative payload). ISLs can operate in RF frequencies or optical bands.

[0085] (6) The terminal is served by a satellite (or UAS platform) within the target service area.

[0086] like Figure 3As shown in the figure, it is a schematic diagram of the communication between the satellite base station and the terminal. In the NTN scenario, due to the long transmission distance from the satellite to the ground and the large loss, the satellite base station will use a high-gain narrow beam to point directionally to the service terminal to ensure the link service performance. The satellite side can obtain the location of the terminal and calculate the straight-line transmission direction between the satellite and the ground terminal based on its own ephemeris and the location of the terminal. Figure 4 As shown in the figure, it is a schematic diagram of the satellite channel. Considering that the overall scattering environment of the satellite channel is relatively simple, mainly line-of-sight (LoS), and the scatterers are mostly concentrated on the terminal side, the transmission direction calculated based on the position can be considered as the transmission direction of the narrow beam. In addition, the satellite can also obtain the narrow beam transmission direction that is most suitable for the terminal through narrow beam-level beam management. It should be noted that whether it is a narrow beam direction calculated based on the position or a narrow beam direction obtained based on beam management, the goal is to optimize the service quality of a single terminal, and does not consider the scenario where other terminals exist.

[0087] On the other hand, compared with ground systems, satellites move faster and have longer transmission delays, which makes the satellite channel time-varying phenomenon more significant. Satellite systems mostly use frequency division duplexing (FDD) and need to use channel state information-reference signal (CSI-RS) to measure channels and feedback to obtain channel-related information (e.g., channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), etc.). In this case, high round-trip delay and long channel measurement cycle will make it impossible for channel feedback information to match the rapidly changing channel state in time, that is, it will be significantly affected by channel aging, resulting in a significant decrease in data transmission performance.

[0088] In the NR ground system, the base station obtains channel information by sending CSI-RS to the terminal. The terminal performs channel measurement based on CSI-RS and feeds back the PMI that matches the channel state to the base station. The base station can perform weighted processing on the CSI-RS through weight design, thereby forming a number of CSI-RS ports that is less than the number of base station transmit antennas. The terminal notifies the base station of the precoding results in the form of PMI codebook feedback based on the channels on multiple CSI-RS ports. Generally, the terminal will perform eigendecomposition on the covariance matrix of the estimated downlink channel, that is,

[0089] R=H H H=UΛUH

[0090] in, represents the downlink channel from the base station to the terminal, N R is the number of terminal receiving antennas, and P is the number of CSI-RS ports. U is the unitary matrix after the decomposition of the covariance matrix R. The L-layer PMI fed back by the terminal usually contains the main spatial transmission direction of the channel, that is, the 1st to L columns of the U matrix, but does not contain the weight information of each transmission direction, that is, the first L diagonal elements of the Λ matrix.

[0091] There are three main types of PMI codebooks, namely Type I, Type II and Type II PS codebooks. Among them, Type I codebook mainly uses one or more columns of DFT vectors to match one or more strong paths in the multipath channel transmission space (columns 1 to L of the U matrix); Type II codebook mainly uses several columns of discrete Fourier transform (DFT) vectors to perform linear combination to match multiple strong paths in the channel transmission space; and Type IIPS codebook mainly transmits CSI-RS by weighting the base station side, and the terminal selects some ports from multiple CSI-RS ports for linear combination, indicating that the base station side uses multiple columns of CSI-RS weights for linear combination to match multiple strong paths in the channel space. The form of the first column of the PMI matrix corresponding to various codebook types can be summarized as shown in Table 1 below:

[0092] Table 1

[0093]

[0094] in, v l represents a column of DFT vectors, is the rotation phase, is the port indicator matrix, w l represents the combination coefficient between ports. Since the PMI codebook in the NR protocol is mainly designed based on the MIMO array form, and the base station side uses dual linear polarization antennas for transmission by default, f l and All match this codebook feature. For example, the number of CSI-RS ports is 4 and the PS codebook selects ports 2 and 3.

[0095]

[0096] During the channel measurement process, the base station mainly obtains PMI feedback or designs CSI-RS weights for a single terminal. For a single terminal scenario, the weight of data transmission can be expressed as W PDSCH =W CSI WPMI . For multiple terminal scenarios, based on the channel feedback results of multiple terminals, the base station calculates the correlation between the terminal data weights, determines which terminals can be paired into a group for spatial division transmission, and designs multi-terminal weights for these paired terminals. Usually, the base station will adopt a linear precoding design method, such as a multi-terminal zero forcing scheme, to calculate the weights used in actual transmission. During data transmission, the zero forcing scheme can eliminate interference between terminals, but to a certain extent, it will cause a significant decrease in the performance of a single terminal. The transmission weight design process for multiple terminals in the ground system is as follows: Figure 5 shown.

[0097] However, the above codebook is mainly designed for SU channels and dual-polarized antennas, and is not robust enough to fast time-varying channel environments. Specifically, it mainly includes the following problems:

[0098] (1) The NR standard PMI is mainly designed for single-terminal channels. The channels on each antenna port belong to the terminal. Therefore, except for the PS codebook, other codebooks do not have a focus on port feedback, that is, they are not suitable for feedback in scenarios where some ports are target channels and some ports are interference channels. In addition, PMI only feeds back the transmission direction characteristics of the terminal, and does not contain the weight information of the transmission direction.

[0099] (2) The PMI of the NR standard is mainly based on the assumption of dual-polarized antennas at the base station end, that is, the first half and the second half of the codebook belong to different polarization directions, but the beam or port indicator vectors used are exactly the same, with only differences in phase or coefficient. However, in the NTN scenario, satellites generally use left-hand or right-hand single polarization, which makes the first half of the CSI-RS port and the second half of the port have no relationship between the beam directions, so the NR codebook is not suitable for the NTN scenario.

[0100] (3) In the NR standard, regardless of periodic CSI-RS, semi-constant CSI-RS or aperiodic CSI-RS, the PMI fed back by the terminal is the channel weight at the current measurement time. In the NTN scenario, due to the high satellite movement speed and large transmission delay, when the PMI at the measurement time is fed back to the satellite base station, the amplitude and phase of the channel may have changed significantly, resulting in the lack of robustness of NR weight feedback applied to NTN.

[0101] In the satellite system, the satellite base station uses a directional narrow beam to serve the target terminal. Considering that the satellite channel is LoS-biased and can usually only support single-stream transmission, the satellite can use the beam direction as the CSI-RS weight according to the transmission direction to the terminal, form a single-port channel measurement (no need to feedback PMI), and limit the terminal to only feedback CQI. In fact, because CQI only reflects channel quality information and has a coarse granularity, it is not sensitive to channel time variation, so it has a more robust transmission performance for the scenario of a single terminal. For scenarios with multiple terminals, the satellite can use the beam in the corresponding direction for each terminal, but in order to avoid mutual interference between beams, the satellite base station needs to perform space division multiplexing on some beams and frequency division or time division multiplexing on some beams. Among them, space division multiplexing means that beams in different directions with correlation between beams less than a certain threshold can be sent at the same time and the same frequency band, while frequency division or time division multiplexing means that multiple beams need to be sent at different frequency bands or different times. For example, common frequency division multiplexing includes four-color multiplexing (different filled shapes in the figure represent different frequency bands or times), and beams with adjacent directions are sent simultaneously on four different frequency bands, such as Figure 6 shown.

[0102] Space division multiplexing can make the most effective use of time and frequency resources, but it has a correlation requirement (also known as isolation) for beam groups that can be spaced simultaneously, especially since beams in adjacent directions are usually difficult to allocate in the same space group. Frequency division or time division multiplexing has no requirements for the correlation between beams and can be flexibly selected, but it will lead to a significant decrease in spectrum efficiency. Therefore, for multi-terminal transmission, it is necessary to consider both resource utilization and the performance impact caused by interference between terminals.

[0103] For the current satellite system, if frequency division or time division multiplexing is used between beams, the spectrum efficiency will be significantly reduced, and the resource utilization rate will not be as high as that of full frequency multiplexing; if space division multiplexing is used, the interference between beams will gradually become more significant as the number of terminals increases, and the number of beams that meet the isolation requirements between beams in the space division beam group will also be limited, resulting in the overall capacity of the satellite being limited and unable to grow linearly with the number of beams.

[0104] To this end, the present application provides a communication solution to solve the problem that in the NTN system, when the terminal only feeds back CQI, the satellite cannot obtain complete channel information and is difficult to handle multi-beam interference, thereby limiting the system capacity improvement; and when the terminal adopts the NR protocol PMI feedback process, the feedback codebook used does not match the satellite scenario and is not robust to time-varying channels, thereby limiting the system capacity improvement.

[0105] The following is based on Figure 1 The communication system shown describes the communication method provided by the present application:

[0106] In this application, "sending information to... (for example, a terminal)" or the related illustrations in the accompanying drawings can be understood as the destination end of the information is the terminal. It can include sending information to the terminal directly or indirectly. "Receiving information from... (for example, a terminal)" or "receiving information from... (for example, a terminal)", or the related illustrations in the accompanying drawings can be understood as the source end of the information is the terminal, which can include receiving information from the terminal 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.

[0107] The communication method provided by the embodiment of the present application is described in detail below. It can be understood that the present application uses the terminal and the server as the execution subject of the interactive schematic as an example for illustration, but the present application does not limit the execution subject of the interactive schematic. For example, the terminal in the method provided by the present application may also be a chip, a chip system, or a processor applied to the terminal, or a logical node, a logical module, or software that can implement all or part of the terminal; the server in the method provided by the present application may also be a chip, a chip system, or a processor applied to the server, or a logical node, a logical module, or software that can implement all or part of the server function.

[0108] like Figure 7 FIG. 1 is a flow chart of a communication method provided in an embodiment of the present application. Exemplarily, the method may include the following steps:

[0109] S701. The network device divides K terminals into the same group according to the weight vectors corresponding to the main transmission directions of the K terminals, wherein the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2.

[0110] Exemplarily, the network device in this embodiment may be a satellite base station. The satellite base station determines the main transmission direction from the satellite to the i-th terminal based on the location information reported by the i-th terminal or based on the beam management result. Wherein, i is a positive integer and is less than or equal to K. Assuming that the satellite base station uses a uniform planar array (UPA) antenna, the main transmission direction of the i-th terminal is determined as in, is the horizontal angle, is the vertical angle, then the weight vector corresponding to its main transmission direction can be expressed as in, Indicates the transmission direction is When , the corresponding array steering vector. From the formula, It can be expressed as

[0111]

[0112]

[0113]

[0114] Among them, N x and N y are the number of antenna elements in the horizontal and vertical directions, d x and d y are the antenna array spacing in the horizontal and vertical directions respectively, and λ represents the wavelength of the carrier center frequency.

[0115] Satellite base station based on multiple terminals A total of K terminals are selected for pre-pairing. The pairing criteria may be that the correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to the first threshold; or, the isolation of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to the second threshold; or, the interval of the transmission angles of the main transmission directions of the K terminals is greater than or equal to the third threshold, etc. The first threshold, the second threshold, and the third threshold may be predefined by the protocol, or obtained through negotiation between the network device and the terminal.

[0116] S702. The network device obtains a reference signal weight matrix corresponding to the reference signal port group.

[0117] In this embodiment, the reference signal is described by taking CSI-RS as an example. Of course, it may also be other reference signals used for channel measurement.

[0118] The satellite base station configures a set of shared CSI-RS port numbers for the K paired terminals, that is, the number of CSI-RS ports for each terminal is K, and the satellite uses the same CSI-RS weight vector for these K terminals. Among them, on the i-th port, the CSI-RS weight vector is equal to the weight vector corresponding to the transmission direction of the i-th terminal That is, the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal.

[0119] like Figure 8 As shown in FIG. 1 , it is a schematic diagram of terminal pairing. Taking K=4 terminal pairing as an example, the four paired terminals are all assigned CSI-RS ports 0 to 3, and the CSI-RS weight matrix W CSI The i-th column of is:

[0120]

[0121] in, Express Take the conjugate.

[0122] It can be seen that for the ith terminal, among the channels to be measured after the CSI-RS weight, only the ith port is the target channel of the main transmission direction of the terminal, and the remaining ports are interference channels caused by the main transmission direction of the paired terminal. CSI The corresponding channels after weighting are measured and fed back for designing multi-terminal data transmission weights on the satellite side.

[0123] S703. The network device sends reference signals to the K terminals at the reference signal port group at multiple times according to the reference signal weight matrix. Correspondingly, the K terminals receive the reference signals from the network device respectively.

[0124] The network device groups the terminals, and the terminals in the same group use the same reference signal port number group. After obtaining the reference signal weight matrix corresponding to the reference signal port group, the network device sends reference signals to K terminals in the reference signal port group at multiple times according to the reference signal weight matrix, so that the K terminals can measure the received reference signals respectively.

[0125] The network side pairs the scheduled terminals in advance and designs the CSI-RS weight vector for the paired terminals, so that the terminals can simultaneously measure their own target channel states and other users' interference channel states.

[0126] Furthermore, the method may also include the following steps (indicated by dotted lines in the figure):

[0127] S704. The K terminals send channel measurement results to the network device respectively, and correspondingly, the network device receives the channel measurement results from the K terminals.

[0128] Assume that at time t, the channel of the i-th terminal is It can be expressed as

[0129]

[0130] in, Characterizes the time-varying channel coefficient and obeys the complex Gaussian distribution, that is, It only contains the steering vector related to the actual transmission angle, and it can be considered to remain unchanged within a period of time T (for example, within 1 second); L is the number of transmission paths of the channel. According to the above measurement phase, the multi-port CSI-RS weight of the paired terminal is a vector:

[0131]

[0132] Then the CSI-RS equivalent channel received by the i-th terminal can be expressed as:

[0133]

[0134] It can be seen that the equivalent channel of the i-th terminal is Furthermore, the first parameter and the reference signal weight matrix W CSI , and the array steering vector corresponding to the transmission direction Association, where the first parameter It can be considered to remain unchanged during time T.

[0135] In order to eliminate the impact of time-varying channels, the terminal only feeds back Related information, the terminal can be 0≤t1 within the time from 0 to T <t2<…<t N ≤T / 2, these N channels sending CSI-RS are statistically averaged to extract The terminal can calculate:

[0136]

[0137] And Provide feedback according to a certain rule.

[0138] That is, the channel measurement result of this embodiment is based on the statistical average value of equivalent channels at multiple moments, and the equivalent channel is a channel estimated based on the reference signal.

[0139] This embodiment illustrates two implementation methods of the terminal feeding back the channel measurement result:

[0140] In a first implementation manner, the statistical average value is a covariance matrix, and the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

[0141] Considering that for the i-th terminal, only the channel on the i-th port is the target channel, and the channels on the remaining ports come from the interference of other terminals, and:

[0142]

[0143] From this we can conclude that The i-th column element represents the inner product of the CSI-RS weight vector corresponding to each channel path of the terminal and the transmission direction of the terminal, so it has the highest amplitude; while the other column elements are the inner products of the CSI-RS weights corresponding to the terminal channel and the transmission directions of the other terminals, and the amplitude is relatively low. Thus, the covariance matrix It can be expressed as:

[0144]

[0145] Among them, a T represents transpose, a * Indicates conjugation.

[0146]

[0147] The average power of the lth channel path is ρ l , and there is as well as

[0148]

[0149] It can be seen that Each element of is actually the weighted correlation between the ports of the i-th terminal receiving channel. Therefore, The element in row i and column i of The autocorrelation of channel port i is the highest, while the other elements are the cross-correlations between ports, with relatively low amplitudes. is the conjugate transposed matrix, then the terminal can be The amplitude is used as the reference, and only the amplitude and phase of the elements in the upper half matrix whose amplitude is higher than a certain threshold are fed back. The kth column of the matrix is ​​only from the (K-k+1) elements in the upper half of the matrix, for the values ​​with amplitude greater than The elements are quantized and fed back, where η≤1 is the preset amplitude ratio threshold. The quantization method of the elements can be to use a limited number of bits to quantize the amplitude and phase of the elements respectively, and feed back the corresponding bits, which is the same as the coefficient quantization method in the current NR standard and will not be repeated here. Through this feedback method, the satellite base station can obtain complete multi-terminal channel covariance information with limited feedback overhead, which includes both the main transmission direction characteristics of the channel and the weights of each direction.

[0150] The satellite base station can restore the channel covariance matrix of each terminal based on the channel information fed back by K terminals. Based on these covariance matrices, multi-terminal precoding is designed and optimized. Common precoding design methods include:

[0151] (1) The goal is to maximize the average signal-to-interference-plus-noise ratio (SINR) of each terminal, that is,

[0152]

[0153] Among them, ASINR i represents the long-term statistical average signal-to-noise ratio of the i-th user, W PMIis the precoding matrix to be solved, the i-th column of which represents the precoding vector used for the i-th user data transmission, σ 2 Represents the Gaussian noise variance after normalization by transmit power.

[0154] Solving for W PMI After that, the data transmission weight of the i-th terminal can be expressed as

[0155] W PDSCH,i =W CSI W PMI [:,i]

[0156] (2) The goal is to maximize the average signal-to-leakage-plus-noise ratio (SLNR) of each terminal, that is,

[0157]

[0158] Solving for W PMI After that, the data transmission weight of the i-th terminal can be expressed as

[0159] W PDSCH,i =W CSI W PMI [:,i]

[0160] like Fig. 9 As shown, it is a schematic diagram of the interaction process between a network device and a terminal over time provided by an embodiment of the present application, and the process includes: S901. The network device determines the paired terminal according to the angle prior information; S902. The network device calculates the CSI-RS weight vector of the paired terminal; S903. The network device calculates the CSI-RS weight vector of the paired terminal at multiple times (t1, t2, ...t N ) sends CSI-RS to the terminal; S904. The terminal measures the CSI-RS and calculates the statistical covariance; S905. The terminal feeds back the statistical covariance to the network device; S906. The network device calculates the weights of multiple terminals; and S907. The network device and the terminal transmit data based on the calculated weights of multiple terminals.

[0161] It should be noted that although this implementation is mainly described for multiple terminal scenarios, this implementation can also be used for channel measurement and feedback in a single terminal scenario, and improve the transmission rate of a single terminal. Unlike the scenario of multiple terminals, in the scenario of a single terminal, the satellite base station needs to determine several transmission angle directions in advance to form the CSI-RS weights. These angle directions can be directions close to the main transmission direction, so that the satellite can perform joint transmission through multiple channel paths, improve channel quality, and use diversity gain to increase the transmission rate.

[0162] The scheduling terminals are paired in advance through network equipment, and the CSI-RS weights are designed for the paired terminals, so that the terminals can simultaneously measure their own target channel states and the interference channel states of other terminals. In addition, the terminals perform statistical averaging of the CSI-RS receiving channels at multiple times, calculate the covariance matrix, and feed back some elements with higher amplitudes in the covariance matrix. With low feedback overhead, the base station can simultaneously obtain the transmission direction and directional weights of the target channel and the interference channel, which facilitates the satellite to design more robust and high-capacity low-interference transmission weights for multiple terminals.

[0163] like Fig.10 As shown in FIG. 1 , it is a schematic diagram of the process of performing terminal pairing based on angle prior information in an embodiment of the present application. In this embodiment, the satellite base station first determines the pairing information of the scheduled terminal, and then designs robust multi-terminal weights based on the channel covariance matrix feedback of each terminal. Figure 5 The improvements of the process shown are: (1) based on the prior information of the transmission angle, the interference situation between the multi-terminal beams is determined in advance, and the CSI-RS weight is designed to enable the terminal to perform deterministic measurements on the target channel and the interference channel at the same time; (2) based on the CSI-RS weight configuration and satellite channel characteristics, the terminal provides feedback on some elements of the statistically averaged channel covariance matrix. While avoiding excessive feedback overhead, it can eliminate the impact of the time-varying channel and simultaneously provide feedback on the transmission direction and directional weight of the channel, which facilitates the satellite base station to design more robust data weights that can reduce interference between terminals.

[0164] In the second implementation method, the statistical average is the covariance matrix, and the channel measurement results include the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, where l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

[0165] Similar to the first implementation, the satellite base station pairs the scheduled terminals in advance based on the angle prior information and calculates the CSI-RS weights according to the main transmission direction of the paired terminals. The terminal calculates the channel covariance matrix based on the statistical average of the measured CSI-RS equivalent channel. Different from the first implementation, in this implementation, the terminal does not directly feed back multiple elements of the covariance matrix, but performs eigendecomposition on the covariance matrix to obtain the first l′ column vectors of the characteristic unitary matrix. That is,

[0166]

[0167] Among them, Λ i,ant is a diagonal matrix whose diagonal elements are The terminal feedback matrix U i,ant [:,1:l′], and for each column, the port indicator vector and the quantized port coefficient are fed back, where the port indicator vector has The first element is 1, the rest are 0, and the position of element 1 indicates the port of the coefficient to be fed back. This feedback method is similar to the Type II PS codebook in the NR standard, but the multiplexing relationship between the first half of the ports and the second half of the ports is no longer limited.

[0168] The satellite base station recovers the And further design multi-terminal low interference weights. Common precoding design methods include:

[0169] (1) Zero-forcing criterion: the satellite base station first Arranged in terminal order:

[0170]

[0171] Then the W of all terminals PMI Should be:

[0172]

[0173] This scheme requires that each terminal has l′=1

[0174] (2) Maximize the SINR or SLNR of each terminal, and the optimization problem is:

[0175]

[0176] or

[0177]

[0178] Please refer to the above description for the meaning of each parameter in this formula.

[0179] The interaction process between the network device and the terminal over time is the same as that of the first implementation method and will not be repeated here.

[0180] This implementation method pairs the scheduling terminals in advance through network equipment, and designs the form of CSI-RS weights for the paired terminals, enabling the terminals to simultaneously measure their own target channel states and the interference channel states of other terminals. In addition, the terminal performs statistical averaging of the CSI-RS receiving channels at multiple times, calculates the covariance matrix, and feeds back the first several columns of the unitary matrix after the characteristic decomposition of the covariance matrix. In the case of maximizing the reuse of the NR standard design, the network equipment is enabled to simultaneously obtain the transmission directions of the target channel and the interference channel, which facilitates the satellite to design more robust multi-terminal low-interference transmission weights, thereby increasing the single-satellite capacity compared to traditional satellite solutions.

[0181] This implementation maximizes the reuse of the NR standard process and Type II codebook design, but cancels the multiplexing relationship between the first half of the ports and the second half of the ports in the NR codebook, so that the terminal can flexibly select the feedback port according to the actual port coefficient situation, which is more in line with the design scheme and NTN channel environment.

[0182] According to a communication method provided in an embodiment of the present application, a network device pairs multiple terminals according to weight vectors corresponding to the main transmission directions of the multiple terminals, configures a set of shared reference signal weight matrices for the paired terminals, and sends reference signals to the paired terminals at a reference signal port group at multiple times based on the reference signal weight matrix, thereby realizing channel measurement of the NTN network and improving the robustness of the channel measurement.

[0183] It can be understood that in the above embodiments, the methods and / or steps implemented by the terminal can also be implemented by components (such as chips or circuits) that can be used for the terminal; the methods and / or steps implemented by the network device can also be implemented by components (such as chips or circuits) that can be used for the network device.

[0184] The above mainly introduces the scheme provided by the embodiment of the present application from the perspective of interaction between various nodes. Accordingly, the embodiment of the present application also provides a communication device, which is used to implement the above various methods. The communication device can be a terminal in the above method embodiment, or a component that can be used for the terminal; or, the communication device can be a network device in the above method embodiment, or a component that can be used for the network device. It can be understood that in order to implement the above functions, the communication device includes a hardware structure and / or software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiment disclosed herein, 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 the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0185] The embodiment of the present application can divide the functional modules of the communication device according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0186] Based on the same concept of the above communication method, the present application also provides the following communication device:

[0187] like Fig.11 , which is a schematic diagram of the structure of a communication device provided in an embodiment of the present application, the communication device 1100 includes a transceiver unit 1101 and a processing unit 1102; wherein:

[0188] When the communication device is used to implement the function of the terminal in the above method embodiment, the transceiver unit 1101 is used to execute the following steps: Figure 7 The operations of the terminal in S703 and S704 in the illustrated embodiment.

[0189] When the communication device is used to implement the function of the network device in the above method embodiment, the transceiver unit 1101 is used to execute the following steps: Figure 7 In the embodiment shown, the operation of the network device in S703 and S704, and the processing unit 1102 are used to perform the following steps: Figure 7 The operations of S701 and S702 in the illustrated embodiment.

[0190] For the specific implementation of the above-mentioned transceiver unit 1101 and the processing unit 1102, reference may be made to the description in the above-mentioned method embodiment.

[0191] like Fig.12 As shown, it is a schematic diagram of the structure of another communication device provided in an embodiment of the present application, and the communication device 1200 includes one or more processors 1201 (one processor is illustrated in the figure). Optionally, the communication device 1200 may also include a memory 1203 (indicated by a dotted line in the figure). The memory 1203 is used to store instructions executed by the processor 1201, or to store input data required for the processor 1201 to run instructions, or to store data generated after the processor 1201 runs instructions. Optionally, the communication device 1200 may also include an interface circuit 1202 (indicated by a dotted line in the figure), and the processor 1201 and the interface circuit 1202 are coupled to each other. It can be understood that the interface circuit 1202 can be a transceiver or an input-output interface. Among them, the processor 1201 is used to implement the above Fig.11 The functions of the processing unit 1102 in the embodiment shown; and the interface circuit 1202 are used to implement the above Fig.11 The functions of the transceiver unit 1101 in the illustrated embodiment.

[0192] When the above communication device is a chip applied to a terminal, the chip implements the functions of the terminal in the above method embodiment. The chip receives information from other modules in the terminal (such as a radio frequency module or an antenna), and the information is sent by the network device to the terminal; or the chip sends information to other modules in the terminal (such as a radio frequency module or an antenna), and the information is sent by the terminal to the network device.

[0193] When the above communication device is a chip applied to a network device, the chip implements the function of the network device in the above method embodiment. The chip 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 terminal to the network device; or the chip 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 terminal.

[0194] In addition, it should be noted that the aforementioned transceiver unit and / or processing unit can be implemented through a virtual module, for example, the processing unit can be implemented through a software function unit or a virtual device, and the transceiver unit can be implemented through a software function or a virtual device. Alternatively, the processing unit or the transceiver unit can also be implemented through a physical device, for example, if the device is implemented using a chip / chip circuit, the transceiver unit can 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 is an integrated processor or microprocessor or integrated circuit.

[0195] The division of modules in this application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each example of this application may be integrated into one processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0196] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or 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.

[0197] 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.

[0198] The embodiments of the present application also provide a computer program product including instructions, which, when executed on a computer, enables the computer to execute the method in the above embodiments.

[0199] An embodiment of the present application also provides a communication system, including the above-mentioned communication device.

[0200] The embodiment of 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.

[0201] When the above-mentioned communication device is a module applied to a base station, the base station module implements the functions of the base station in the above-mentioned method embodiment. The base station module receives information from other modules in the base station (such as a radio frequency module or an antenna), and the information is sent by the terminal to the base station; or, the base station module sends information to other modules in the base station (such as a radio frequency module or an antenna), and the information is sent by the base station to the terminal. The base station module here can be a baseband chip of a base station, or a CU, DU or other module, or a device under an open radio access network (O-RAN) architecture, such as an open CU, an open DU and other devices.

[0202] 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.

[0203] In this application, the 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 circuits in the aforementioned devices for implementing processing functions, which may implement or execute the 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 method disclosed in this application may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0204] 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.

[0205] Optionally, the embodiment of the present application further provides a chip system, including: at least one processor and an interface, the at least one processor is coupled to a memory via the interface, and when the at least one processor runs a computer program or instruction in the memory, the chip system executes a 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 embodiment of the present application.

[0206] The memory in the present application may also be a circuit or any other device capable of realizing a storage function, for storing program instructions and / or data. The 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), etc., or a volatile memory (volatile memory), such as a random-access memory (RAM).

[0207] It should be understood that in the description of the present application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship, for example, A / B can represent A or B; wherein A and B can be singular or plural. Also, in the description of the present application, unless otherwise specified, "multiple" refers to 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 items or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, wherein a, b, c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same items or similar items with substantially the same functions and effects. Those skilled in the art can understand that the words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not limit them to be necessarily different. Meanwhile, in the embodiments of the present 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 the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete manner for ease of understanding.

[0208] 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 may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may 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 may be transmitted from a website site, a computer, a network device or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, network device or data center.

[0209] 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 may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in a claim. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0210] It is understood that the various numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic.

[0211] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0212] The components in the device of the embodiment of the present application can be merged, divided and 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.

[0213] In the present application, under the premise of no logical contradiction, the examples may reference each other, for example, the methods and / or terms between method embodiments may reference each other, for example, the functions and / or terms between device embodiments may reference each other, for example, the functions and / or terms between device examples and method examples may reference each other.

Claims

1. A communication method, characterized in that: The method is applied to a first terminal or a chip in the first terminal, and includes: According to a reference signal weight matrix corresponding to a reference signal port group, a reference signal is received at the reference signal port group at multiple time points, wherein the first terminal belongs to any one of K terminals, and according to weight vectors corresponding to main transmission directions of the K terminals, the K terminals are divided into the same group, and the K terminals use the same reference signal port number group, wherein K is a positive integer greater than or equal to 2, and the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and is less than or equal to K.

2. The method according to claim 1, characterized in that The method also includes: the first terminal sending a channel measurement result, where the channel measurement result is based on a statistical average of equivalent channels at the multiple time moments, and the equivalent channel is a channel estimated based on the reference signal.

3. The method according to claim 1 or 2, characterized in that The correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or The isolation degree of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or An interval between transmission angles of main transmission directions of the K terminals is greater than or equal to a third threshold.

4. The method according to any one of claims 1 to 3, characterized in that The equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and an array steering vector corresponding to a transmission direction, and the first parameter remains unchanged during the multiple time moments.

5. The method according to any one of claims 1 to 4, characterized in that The statistical average is a covariance matrix, the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

6. The method according to any one of claims 1 to 5, characterized in that The statistical average is the covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

7. A communication method, characterized in that: The method applied to a network device or a chip in the network device comprises: According to the weight vectors corresponding to the main transmission directions of the K terminals, the K terminals are divided into the same group, wherein the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2; Acquire a reference signal weight matrix corresponding to the reference signal port group, wherein the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and is less than or equal to K; According to the reference signal weight matrix, reference signals are sent to the K terminals at the reference signal port group at multiple time instants.

8. The method according to claim 7, characterized in that The method further includes: the network device receiving channel measurement results from the K terminals.

9. The method according to claim 7 or 8, characterized in that The correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or The isolation degree of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or An interval between transmission angles of main transmission directions of the K terminals is greater than or equal to a third threshold.

10. The method according to any one of claims 7 to 9, characterized in that The equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and an array steering vector corresponding to a transmission direction, and the first parameter remains unchanged during the multiple time moments.

11. The method according to any one of claims 7 to 10, characterized in that: The statistical average is a covariance matrix, the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

12. The method according to any one of claims 7 to 11, characterized in that The statistical average is the covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

13. A communication device, characterized in that: The device comprises: a transceiver unit; wherein: The transceiver unit is used to receive reference signals at the reference signal port group at multiple times according to the reference signal weight matrix corresponding to the reference signal port group, wherein the first terminal belongs to any one of K terminals, and according to the weight vectors corresponding to the main transmission directions of the K terminals, the K terminals are divided into the same group, and the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2. The reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, and the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and is less than or equal to K.

14. The device according to claim 13, characterized in that The transceiver unit is further used to send a channel measurement result, where the channel measurement result is based on a statistical average value of equivalent channels at the multiple time moments, and the equivalent channel is a channel estimated based on the reference signal.

15. The device according to claim 13 or 14, characterized in that The correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or The isolation degree of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or An interval between transmission angles of main transmission directions of the K terminals is greater than or equal to a third threshold.

16. The device according to any one of claims 13 to 15, characterized in that The equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and an array steering vector corresponding to a transmission direction, and the first parameter remains unchanged during the multiple time moments.

17. The device according to any one of claims 13 to 16, characterized in that The statistical average is a covariance matrix, the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

18. The device according to any one of claims 13 to 17, characterized in that The statistical average is the covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

19. A communication device, characterized in that: The device comprises: a processing unit and a transceiver unit; wherein: The processing unit is configured to divide the K terminals into the same group according to the weight vectors corresponding to the main transmission directions of the K terminals, wherein the K terminals use the same reference signal port number group, and K is a positive integer greater than or equal to 2; The processing unit is further used to obtain a reference signal weight matrix corresponding to the reference signal port group, wherein the reference signal weight matrix includes K reference signal weight vectors, each reference signal port corresponds to a reference signal weight vector, the reference signal weight vector corresponding to the i-th reference signal port is equal to the weight vector corresponding to the main transmission direction of the i-th terminal, and i is a positive integer and is less than or equal to K; The transceiver unit is configured to send reference signals to the K terminals at the reference signal port group at multiple times according to the reference signal weight matrix.

20. The device according to claim 19, characterized in that The transceiver unit is further used to receive channel measurement results from the K terminals.

21. The device according to claim 19 or 20, characterized in that The correlation of the weight vectors corresponding to the main transmission directions of the K terminals is less than or equal to a first threshold; and / or The isolation degree of the weight vectors corresponding to the main transmission directions of the K terminals is greater than or equal to a second threshold; and / or An interval between transmission angles of main transmission directions of the K terminals is greater than or equal to a third threshold.

22. The device according to any one of claims 19 to 21, characterized in that The equivalent channel of the i-th terminal is associated with a first parameter, the first parameter is associated with the reference signal weight matrix and an array steering vector corresponding to a transmission direction, and the first parameter remains unchanged during the multiple time moments.

23. The device according to any one of claims 19 to 22, characterized in that The statistical average is a covariance matrix, the channel measurement result includes amplitudes and phases of multiple elements in the covariance matrix, and the amplitudes of the multiple elements are greater than or equal to a fourth threshold.

24. The device according to any one of claims 19 to 23, characterized in that The statistical average is the covariance matrix, and the channel measurement result includes the first l′ column vectors of the characteristic unitary matrix of the covariance matrix, the port indicator vector of each column vector in the l′ column vectors, and the quantized port coefficients, wherein l′ is the number of layers of the precoding matrix used for downlink transmission, and the number of layers is less than or equal to the rank of the covariance matrix.

25. A communication device, characterized in that: The method comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 12 when executing the computer program.

26. A communication system, characterized in that: The method comprises a first communication device and a second communication device, wherein the first communication device is used to execute the method according to any one of claims 1 to 6, and the second communication device is used to execute the method according to any one of claims 7 to 12.

27. A chip, characterized in that: The chip is used to execute the method according to any one of claims 1 to 12.

28. A chip module, characterized in that: The invention comprises an interface component and a chip, wherein the chip is used to execute the method according to any one of claims 1 to 12.

29. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction. When the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 12 is implemented.

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