Communication method and apparatus

Abstract

The present application relates to the technical field of communications, and provides a communication method and apparatus, which can save resources of a terminal. In the method, a terminal receives a first reference signal from a network device by means of a first device. The terminal sends first indication information on the basis of the first reference signal, the first indication information being used for indicating a channel measurement state of the terminal. The channel measurement state of the terminal comprises a non-channel acquisition state or a channel acquisition state. The channel acquisition state indicates that the terminal performs measurement on a channel (referred to as a first channel) between the network device and the terminal and through the first device, and the non-channel acquisition state indicates that the terminal does not perform measurement on the first channel. When the channel measurement state of the terminal is the non-channel acquisition state, the terminal may not perform measurement on the first channel, thereby saving resources of the terminal.

Description

Communication method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 8, 2024, with application number 202410178338.X and application name “Communication Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0003] Multiple-input multiple-output (MIMO) technology is an important communication technology that uses multiple transmitting antennas at the transmitting end and multiple receiving antennas at the receiving end to transmit and receive signals respectively, achieving multiple transmissions and multiple receptions, thereby improving communication quality.

[0004] In MIMO technology, base stations and terminals need to measure the channel between them to achieve optimal communication. For example, the base station sends a channel state information reference signal (CSI-RS) to the terminal. After measuring the CSI-RS, the terminal sends the channel state information to the base station. The base station then determines a precoding codebook based on the channel state information, precodes the data using the precoding codebook, and then sends the precoded data to the terminal.

[0005] How to consume less resources in the process of measuring the channel between the base station and the terminal is an urgent problem to be solved. Summary of the Invention

[0006] The present application provides a communication method and apparatus that can reduce air interface resource overhead.

[0007] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions:

[0008] In a first aspect, a communication method is provided. The method may be executed by a terminal; alternatively, the method may be executed by a module implemented in the terminal, such as a chip, a chip system, or a circuit; alternatively, the method may be implemented by a logic module or software capable of implementing all or part of the terminal's functions, without limitation. For example, the method may be a communication module in the terminal, or a circuit or chip in the terminal responsible for communication functions (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core). For ease of description, the following description uses execution by a terminal as an example.

[0009] The method includes: a terminal receives a first reference signal from a network device through a first device; based on the first reference signal, first indication information is sent, where the first indication information is used to indicate a channel measurement state of the terminal; the channel measurement state of the terminal includes a non-channel acquisition state or a channel acquisition state, where the channel acquisition state indicates that the terminal measures a first channel, and the non-channel acquisition state indicates that the terminal does not measure the first channel, where the first channel is a channel between the network device and the terminal via the first device.

[0010] With this solution, after receiving the first reference signal, the terminal sends first indication information based on the first reference signal. When the first indication information indicates that the terminal's channel measurement state is a non-channel acquisition state, the terminal does not need to measure the first channel, thereby saving resources consumed by the terminal in measuring the first channel.

[0011] With reference to the first aspect, in a possible implementation manner, the channel measurement state of the terminal is a non-channel acquisition state, and the terminal does not send channel state information of the first channel to the network device.

[0012] With this solution, in the non-channel acquisition state, the terminal does not need to measure the first channel or send the channel state information of the first channel to the network device, thereby saving air interface resources occupied by the channel state information of the first channel.

[0013] In combination with the first aspect, in a possible implementation manner, the channel measurement status of the terminal is indicated by S bits, where S is a positive integer and S is less than the number of bits occupied by the channel status information indicating the first channel.

[0014] With reference to the first aspect, in a possible implementation, the channel measurement status of the terminal is indicated by one bit.

[0015] With this method, since only 1 bit is required for the first indication information to indicate the channel measurement state of the terminal, fewer bits are needed. Therefore, compared with the terminal feeding back the channel state information of the first channel to the network device after receiving the first reference signal, this application can reduce the consumption of radio interface resources by sending the first indication information. In addition, the resources consumed by the first device for forwarding the channel state information of the first channel are reduced.

[0016] Combined with the first aspect, in a possible implementation, 0 represents the non-channel acquisition state, and 1 represents the channel acquisition state.

[0017] Combined with the first aspect, in a possible implementation, when the channel measurement state of the terminal is the channel acquisition state, after sending the first indication information, the method further includes: the terminal receives a second reference signal from the network device through the first device; the terminal measures the first channel, including: the terminal measures the second reference signal to obtain the channel state information of the first channel; the method further includes: sending the channel state information of the first channel.

[0018] Through this solution, when the channel measurement state of the terminal is the channel acquisition state, the network device sends the second reference signal, and the terminal can measure the channel state information according to the second reference signal and then feedback it to the network device.

[0019] Combined with the first aspect, in a possible implementation, when the channel measurement state of the terminal is the channel acquisition state, the method further includes: the terminal measures the first reference signal and the second reference signal to obtain the channel state information of the first channel.

[0020] For example, when both the first reference signal and the second reference signal are channel state information reference signals, the terminal needs M reference signals to measure the channel state information. The number of first reference signals sent by the network device is N, where M and N are positive integers and N < M. The network device can send M - N second reference signals, and the terminal determines the channel state information based on N first reference signals and M - N second reference signals, so that the network device does not need to send M second reference signals, that is, it sends N fewer second reference signals, thus saving radio interface resources.

[0021] Combined with the first aspect, in a possible implementation, after receiving the first reference signal from the network device through the first device, it further includes: the terminal measures the first reference signal, and the channel measurement state of the terminal is determined according to the measurement result of the first reference signal.

[0022] In combination with the first aspect, in one possible implementation method, measuring the first reference signal includes: the terminal measuring at least one of the following indicators of the first reference signal: reference signal received power RSRP, signal-to-noise ratio SNR, reference signal received quality RSRQ, reference signal received intensity RSSI or delay power spectrum.

[0023] In combination with the first aspect, in a possible implementation manner, the channel measurement state of the terminal is a channel acquisition state. After sending the first indication information, the method further includes: the terminal sending an uplink reference signal to the network device through the first device.

[0024] With this solution, the network device can measure the channel state information of the first channel based on the uplink reference signal sent by the terminal, thereby quickly obtaining the channel state information of the first channel. This eliminates the need for the network device to wait for the terminal to feedback the channel state information after sending the reference signal to the terminal via the first device. This solution can reduce latency and achieve better communication between the network device and the terminal.

[0025] With reference to the first aspect, in a possible implementation manner, a configuration of the second reference signal is the same as a configuration of the first reference signal.

[0026] In combination with the first aspect, in a possible implementation manner, the configuration of the second reference signal is different from the configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and the pattern of the reference signal.

[0027] In combination with the first aspect, in one possible implementation, the configuration of the second reference signal is different from the configuration of the first reference signal and includes one or more of the following: the number of the second reference signals is greater than the number of the first reference signals, and the pattern of the second reference signal is different from the pattern of the first reference signal.

[0028] With this solution, the number of second reference signals is greater than the number of first reference signals. This allows the network device to obtain channel state information based on the first indication information of the terminal by transmitting a relatively small number of first reference signals when not in the channel acquisition state. This reduces the air interface resources occupied by the network device to obtain a large number of second reference signals transmitted over the channel between the first device and the terminal.

[0029] In combination with the first aspect, in a possible implementation, there are multiple first reference signals, and the multiple first reference signals meet the following conditions, then the channel measurement state of the terminal is a non-channel acquisition state: there is a third reference signal among the multiple first reference signals, and the difference between the measured value of the indicator of the third reference signal and the measured value of the indicator of each first reference signal other than the third reference signal in the multiple first reference signals is greater than a first threshold; if the multiple first reference signals meet the following conditions, then the channel measurement state of the terminal is a channel acquisition state: the third reference signal does not exist among the multiple first reference signals.

[0030] Through this solution, the terminal measures the channel measurement status of the terminal, which consumes fewer resources than measuring the channel status information of the first channel, thereby saving resources of the terminal.

[0031] In combination with the first aspect, in one possible implementation, the channel through which the first reference signal passes from the first device to the terminal is a line-of-sight LOS channel, and the channel measurement state of the terminal is a non-channel acquisition state; the channel through which the first reference signal passes from the first device to the terminal is a non-line-of-sight NLOS channel, and the channel measurement state of the terminal is a channel acquisition state.

[0032] Through this solution, when the channel from the first device to the terminal is a LOS channel, the terminal's channel measurement state is set to a non-channel acquisition state. This allows the network device to calculate a precoding codebook with higher spectral efficiency, resulting in better communication between the network device and the terminal through the first device.

[0033] In combination with the first aspect, in a possible implementation, the method further includes: the terminal sending second indication information, the second indication information indicating an identifier of a fourth reference signal, the fourth reference signal being a reference signal with the best quality among the multiple first reference signals.

[0034] In conjunction with the first aspect, in one possible implementation, the second indication information includes one or more of the following information: an identifier of the first beam, a time slot of the first beam, a frequency domain position of the first beam, and an identifier of a fourth reference signal. The first beam is a beam carrying the fourth reference signal.

[0035] A second aspect provides a communication method. This method can be executed by a network device; alternatively, it can be executed by a module implemented in the network device, such as a chip, chip system, or circuit; alternatively, it can be implemented by a logic module, logic node, or software that implements all or part of the network device's functions, without limitation. For ease of description, the following description uses execution by a network device as an example.

[0036] The method includes: a network device sends a first reference signal to a first terminal through a first device; receives first indication information, the first indication information is used to indicate a channel measurement state of the first terminal; the channel measurement state of the first terminal includes a non-channel acquisition state or a channel acquisition state, the channel acquisition state instructs the network device to send a second reference signal, the non-channel acquisition state instructs the network device not to send the second reference signal, the second reference signal is used by the first terminal to measure a first channel, the first channel is a channel between the network device and the first terminal through the first device.

[0037] In combination with the second aspect, in a possible implementation manner, the channel measurement status of the first terminal is indicated by one bit.

[0038] In combination with the second aspect, in a possible implementation, the channel measurement state of the first terminal is a channel acquisition state, and the method also includes: the network device sends a second reference signal to the first terminal through the first device; and receives channel state information of the first channel.

[0039] In combination with the second aspect, in a possible implementation manner, the method further includes: the network device determines a precoding matrix according to the channel state information of the first channel.

[0040] In combination with the second aspect, in a possible implementation, the channel measurement state of the terminal is a channel acquisition state. After receiving the first indication information, the method further includes: the network device receives an uplink reference signal sent by the first terminal through the first device.

[0041] With reference to the second aspect, in a possible implementation manner, a configuration of the second reference signal is the same as a configuration of the first reference signal.

[0042] In conjunction with the second aspect, in a possible implementation manner, the configuration of the second reference signal is different from the configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and a pattern of the reference signal.

[0043] In combination with the second aspect, in one possible implementation, the configuration of the second reference signal is different from the configuration of the first reference signal and includes one or more of the following: the number of the second reference signals is greater than the number of the first reference signals, and the pattern of the second reference signal is different from the pattern of the first reference signal.

[0044] In combination with the second aspect, in one possible implementation, a first precoding matrix is ​​determined by first channel information or second channel information, the first precoding matrix is ​​the precoding matrix used by the network device to send data to the first terminal through the first device, the first channel information is the left singular vector matrix obtained after the autocorrelation matrix SVD decomposition of the channel matrix of the second channel, the second channel information is the left singular vector matrix obtained after the autocorrelation matrix SVD decomposition of the product of the channel matrix of the third channel and the channel matrix of the second channel, the second channel is the channel between the network device and the first device, and the third channel is the channel between the first device and the first terminal.

[0045] Through this method, a network device can determine a precoding matrix for sending data to a first terminal based on the first channel information or the second channel information. This allows the network device to determine the precoding matrix for the first channel, even if the terminal does not send the channel state information of the first channel to the network device, thereby sending data to the first terminal via the first channel. This method conserves air interface resources consumed by the terminal indicating the channel state information of the first channel. It also conserves resources occupied by the network device sending a reference signal (such as a second reference signal) used to measure the channel state information of the first channel.

[0046] In combination with the second aspect, in one possible implementation, the channel measurement state of the first terminal is a non-channel acquisition state, and the method also includes: the network device sends data to the first terminal through a third precoding matrix; the third precoding matrix is ​​determined based on the first precoding matrix and the second precoding matrix, and the second precoding matrix is ​​the precoding matrix used by the network device to send data to the first terminal.

[0047] Through this solution, the network device can send data to the first terminal using the third precoding matrix, thereby increasing the spectrum efficiency of communication between the network device and the terminal. Through this solution, the network device separately determines the first precoding matrix and the second precoding matrix, so that when the network device transmits data with multiple terminals through the first device, the first precoding matrix can be reused. This eliminates the need to obtain channel state information for each terminal when communicating with the network device through the first device, reduces the number of reference signals sent for measuring the channel between the first device and the terminal, and conserves air interface resources.

[0048] In combination with the second aspect, in one possible implementation, the channel measurement state of the second terminal is a non-channel acquisition state, and the method also includes: sending data to the second terminal through a fifth precoding matrix; the fifth precoding matrix is ​​determined based on the first precoding matrix and the fourth precoding matrix, and the fourth precoding matrix is ​​the precoding matrix used by the network device to send data to the second terminal through the first device.

[0049] Through this solution, the network device reuses the first precoding matrix, and there is no need to send a reference signal to the second terminal through the first device, thus saving air interface resources.

[0050] In combination with the second aspect, in a possible implementation, the method further includes: the network device receives second indication information, the second indication information indicates an identifier of a fourth reference signal, and the fourth reference signal is a reference signal with the best quality among the multiple first reference signals.

[0051] In conjunction with the second aspect, in one possible implementation, the second indication information includes one or more of the following information: an identifier of the first beam, a time slot of the first beam, a frequency domain position of the first beam, and an identifier of a fourth reference signal. The first beam is a beam carrying the fourth reference signal.

[0052] A third aspect provides a communication method. This method can be executed by a network device; alternatively, it can be executed by a module implemented in the network device, such as a chip, chip system, or circuit; alternatively, it can be implemented by a logic module or software that implements all or part of the network device's functions, without limitation. For ease of description, the following description uses execution by a network device as an example.

[0053] The method includes: sending a first reference signal to a first terminal through a first device; receiving first indication information, wherein the first indication information is used to indicate a channel measurement state of the first terminal; the channel measurement state of the terminal includes a non-channel acquisition state or a channel acquisition state, wherein the channel acquisition state indicates that the network device receives channel state information obtained by the terminal for measuring the first channel based on the first reference signal, and the non-channel acquisition state indicates that the network device does not receive channel state information obtained by the terminal for measuring the first channel based on the first reference signal, the second reference signal is used by the first terminal to measure a first channel, and the first channel is a channel between the network device and the first terminal through the first device.

[0054] Through this solution, the network device may not receive the channel state information of the first channel when the channel measurement state of the terminal is the non-channel acquisition state, thereby saving air interface resources consumed by transmitting the first channel information.

[0055] In combination with the third aspect, reference may be made to possible implementation methods of the second aspect.

[0056] In a fourth aspect, a communication system is provided, comprising a first device and a second device, wherein the second device is used to transmit data between the first device and a third device, the first device executes the method described in the second aspect and any one of its implementations, and the third device executes the method described in the first aspect and any one of its implementations.

[0057] In combination with the fourth aspect, in a possible implementation, the system further includes: a third device.

[0058] In a fifth aspect, a communication device is provided, comprising a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the computer instructions execute the method described in the first aspect and any one of its implementations, or the computer instructions execute the method described in the second aspect and any one of its implementations.

[0059] In a sixth aspect, a chip system is provided, comprising a processor configured to support a communication device in implementing the functions described in the first aspect and any one of its implementations, or in implementing the functions described in the second aspect and any one of its implementations. In one possible design, the chip system further comprises a memory configured to store program instructions and data necessary for the communication device. The chip system may consist of a chip alone, or may include a chip and other discrete components.

[0060] In a seventh aspect, the technical solution of the present application provides a communication device, comprising: a processor, configured to execute any method of any design in any of the above aspects.

[0061] Optionally, the device further includes the memory and / or communication interface.

[0062] The communication interface is coupled to the processor, and is used to receive and / or send signals.

[0063] The memory is used to store computer programs, and the processor is configured to execute the method described in the first aspect and any one of its implementations, which can be implemented as: executing the computer program stored in the memory to execute the method described in the first aspect and any one of its implementations.

[0064] Alternatively, the processor may be a hardware-implemented circuit, such as an artificial intelligence (AI) processor, to increase operating speed. This application does not limit the specific implementation of the processor.

[0065] Optionally, the communication device may be a complete device, or a module in the device, such as a chip.

[0066] In an eighth aspect, a communication device is provided, wherein the communication device has the functionality to implement the method described in the first aspect and any one of its implementations, or has the functionality to implement the method described in the second aspect and any one of its implementations. The functionality may be implemented via hardware or via hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the aforementioned functionality.

[0067] In the ninth aspect, a communication device is provided, comprising: a processor; the processor is used to couple with a memory, and after reading instructions in the memory, execute the method as described in the first aspect and any one of its implementations according to the instructions, or execute the method as described in the second aspect and any one of its implementations according to the instructions.

[0068] In the tenth aspect, a computer-readable storage medium is provided, in which instructions are stored. When the instructions are executed on a communication device, the communication device executes the method described in the first aspect and any one of its implementations, or the communication device executes the method described in the second aspect and any one of its implementations.

[0069] In the eleventh aspect, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the method described in the first aspect and any one of its implementations, or implements the method described in the second aspect and any one of its implementations.

[0070] It can be understood that the beneficial effects that can be achieved by the methods, communication systems, communication devices, computer-readable storage media, computer program products, etc. provided in the second to tenth aspects above can refer to the beneficial effects in the first aspect and any possible implementation method provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] FIG1 is a schematic diagram of the architecture of a communication system used in an embodiment of the present application;

[0072] FIG2 is a schematic diagram of the architecture of another communication system used in an embodiment of the present application;

[0073] FIG3 is a schematic diagram of a process for a base station to obtain a precoding matrix for sending downlink data to a terminal in the related art;

[0074] FIG4 is a flow chart of a communication method according to an embodiment of the present application;

[0075] FIG5 is a flow chart of another communication method according to an embodiment of the present application;

[0076] FIG6A is a schematic diagram of a pattern of a first reference signal according to an embodiment of the present application;

[0077] FIG6B is a schematic diagram of a second reference signal pattern according to an embodiment of the present application;

[0078] FIG6C is a schematic diagram of measuring a time delay power spectrum according to an embodiment of the present application;

[0079] FIG6D is a schematic diagram of a base station sending a beam to a terminal through a RIS according to an embodiment of the present application;

[0080] FIG7A is a schematic diagram of the correlation of precoding matrices according to an embodiment of the present application;

[0081] FIG7B is a schematic diagram of a simulation of a rank in a single-user scenario according to an embodiment of the present application;

[0082] FIG7C is a schematic diagram of a simulation of a rank in a multi-user scenario according to an embodiment of the present application;

[0083] FIG7D is a simulation diagram of spectrum efficiency in a multi-user scenario according to an embodiment of the present application;

[0084] FIG8 is a flow chart of another communication method according to an embodiment of the present application;

[0085] FIG9 is a flow chart of another communication method according to an embodiment of the present application;

[0086] FIG10 is a flow chart of another communication method according to an embodiment of the present application;

[0087] FIG11 is a schematic diagram of a communication device provided in an embodiment of the present application;

[0088] FIG12 is a schematic diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0089] In the description of this 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; "and / or" in this application is merely a description of 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, where A and B can be singular or plural.

[0090] In the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0091] In addition, 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" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0092] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0093] It will be understood that the “embodiment” mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It will be understood that in the various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0094] It can be understood that in this application, "when" and "if" both mean that corresponding processing will be taken under certain objective circumstances, and do not limit the time, nor do they require any judgment action when implementing, nor do they mean that there are other limitations.

[0095] It is understood that some optional features in the embodiments of the present application may, in certain scenarios, be implemented independently of other features, such as the solution on which they are currently based, to solve corresponding technical problems and achieve corresponding effects. They may also be combined with other features in certain scenarios as needed. Accordingly, the devices provided in the embodiments of the present application may also implement these features or functions accordingly, which will not be described in detail here.

[0096] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments in this application, and the various implementation methods / implementation methods / implementation methods in each embodiment, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments and the various implementation methods / implementation methods / implementation methods in each embodiment are consistent and can be referenced to each other. The technical features in different embodiments and the various implementation methods / implementation methods / implementation methods in each embodiment can be combined to form new embodiments, implementation methods, implementation methods, or implementation methods according to their inherent logical relationships. The implementation methods of this application described below do not constitute a limitation on the scope of protection of this application.

[0097] The wireless communication systems mentioned in the solution of the present invention include but are not limited to: narrowband Internet of Things (NB-IoT), global system for mobile communications (GSM), enhanced data rate for GSM evolution (EDGE), wideband code division multiple access (WCDMA), code division multiple access 2000 (CDMA2000), time division-synchronization code division multiple access (TD-SCDMA), long term evolution (LTE), fifth generation (5G), sixth generation (6G) and seventh generation (7G) mobile communication systems.

[0098] FIG1 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of the present application. As shown in FIG1 , the communication system includes a radio access network (RAN) 100 and a core network 200. Optionally, the communication system 1000 may also include the Internet 300. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG1 , collectively referred to as 110), at least one terminal (e.g., 120a-120i in FIG1 , collectively referred to as 120), and at least one first device (e.g., 130 in FIG1 ). The RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG1 ). The terminal 120 is wirelessly connected to the RAN node 110, for example, terminal 120a is directly connected to the RAN node 110, or terminals 120a to 120c are indirectly connected to the RAN node 110 via the first device 130. The RAN node 110 is connected to the core network 200 wirelessly or wiredly. The core network devices in the core network 200 and the RAN nodes 110 in the RAN 100 may be independent and distinct physical devices, or they may be a single physical device that integrates the logical functions of the core network devices and the logical functions of the RAN nodes. Terminals and RAN nodes may be connected to each other via wired or wireless means.

[0099] RAN100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, or a future radio access system defined in the 3rd Generation Partnership Project (3GPP), or a WiFi system. RAN100 can also include two or more of the aforementioned different radio access systems. RAN100 can also be an open RAN (O-RAN).

[0100] A RAN node, also known as a radio access network device, RAN entity, or access node, is used to help terminals access the communication system wirelessly. In one application scenario, a RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. A RAN node can be a macro base station (such as 110a in Figure 1), a micro base station, an indoor station (such as 110b in Figure 1), a relay node, or a donor node.

[0101] In another application scenario, multiple RAN nodes can collaborate to help terminals achieve wireless access, with different RAN nodes implementing portions of the base station's functions. For example, a RAN node can be a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). The CU implements the base station's radio resource control protocol and packet data convergence protocol (PDCP) functions, as well as the service data adaptation protocol (SDAP) functions. The DU implements the base station's radio link control layer and medium access control (MAC) layer functions, as well as some or all of the physical layer functions. For detailed descriptions of each of the above protocol layers, please refer to the relevant 3GPP technical specifications. The RU can be used to implement the transmission and reception of radio frequency signals. The CU and DU can be two independent RAN nodes, or they can be integrated into the same RAN node, such as in a baseband unit (BBU). The RU can be included in radio frequency equipment, such as a remote radio unit (RRU) or an active antenna unit (AAU). The CU can be further divided into two types of RAN nodes: CU-control plane and CU-user plane.

[0102] In different systems, RAN nodes may have different names. For example, in an O-RAN system, a CU may be called an open CU (O-CU), a DU may be called an open DU (O-DU), and a RU may be called an open RU (O-RU). The RAN node in the embodiments of the present application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. For example, the RAN node may be a server loaded with the corresponding software module. The embodiments of the present application do not limit the specific technology and specific device form adopted by the RAN node. For ease of description, the following description takes a base station as an example of a RAN node.

[0103] A terminal is a device with wireless transceiver capabilities that can send signals to a base station or receive signals from a base station. A terminal may also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. A terminal can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle, airplane, ship, robot, robotic arm, smart home device, etc. The embodiments of this application do not limit the specific technology and specific device form adopted by the terminal.

[0104] The first device 130 is a surface composed of a large number of passive components that can adjust their phase and amplitude to change the propagation characteristics of the signal, thereby expanding the coverage of the wireless communication network. The first device 130 can be a reconfigurable intelligent surface (RIS), an intelligent reflecting surface (IRS), an antenna array, a network controlled repeater (NCR), etc.

[0105] The first device 130 can be installed on a large plane (such as a wall or ceiling indoors, a building or sign outdoors) to reflect the surrounding signals. For scenarios where there is no signal transmission path between a communication source (such as a base station) and a target (such as a terminal), for example, between the base station 110a and the terminal 120b, the first device 130 can establish a transmission path for the signal between the communication source and the target, so that the communication source and the target can communicate. For scenarios where there is a signal transmission path between the communication source and the target, for example, between the base station 110a and the terminal 120a, the first device can establish a transmission path for the signal between the communication source and the target, increase the spectrum efficiency (referred to as spectrum efficiency) of the signal transmitted between the communication source and the target, and improve communication performance. For ease of description, RIS is used as an example of the first device below. RIS in the following description can also be replaced by IRS, NCR, etc. This application does not limit the specific form of the first device.

[0106] The base station, first device, and terminal can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the base station and terminal.

[0107] The roles of base stations and terminals can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile base station. To terminals 120e accessing the wireless access network 100 via 120i, terminal 120i is a base station. However, to base station 110a, 120i is a terminal, meaning that communication between 110a and 120i occurs via a wireless air interface protocol. Of course, communication between 110a and 120i can also occur via a base station-to-base station interface protocol. In this case, 120i is also a base station relative to 110a. Therefore, base stations and terminals can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be referred to as communication devices with base station functionality, while 120a-120i in Figure 1 can be referred to as communication devices with terminal functionality.

[0108] Communication between base stations and terminals, between base stations, and between terminals can be carried out through authorized spectrum, unauthorized spectrum, or both; communication can be carried out through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or spectrum below 6 GHz and spectrum above 6 GHz. The embodiments of the present application do not limit the spectrum resources used for wireless communication.

[0109] In the embodiments of the present application, the functions of the base station may also be performed by a module (such as a chip) in the base station, or by a control subsystem that includes the base station functions. The control subsystem that includes the base station functions here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal may also be performed by a module (such as a chip or modem) in the terminal, or by a device that includes the terminal functions.

[0110] In this application, a base station sends downlink signals or downlink information to a terminal, and the downlink information is carried on a downlink channel; the terminal sends uplink signals or uplink information to the base station, and the uplink information is carried on an uplink channel. In order to communicate with the base station, the terminal needs to establish a wireless connection with the cell controlled by the base station. The cell with which the terminal has established a wireless connection is called the serving cell of the terminal. When the terminal communicates with the serving cell, it will also be subject to interference from signals in neighboring cells.

[0111] In the embodiments of the present application, the time domain symbols may be orthogonal frequency division multiplexing (OFDM) symbols or discrete Fourier transform spread OFDM (DFT-s-OFDM) symbols. Unless otherwise specified, the symbols in the embodiments of the present application refer to time domain symbols.

[0112] In the embodiments of the present application, the functions of the base station may also be performed by a module (such as a chip) in the base station, or by a control subsystem that includes the base station functions. The control subsystem that includes the base station functions here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal may also be performed by a module (such as a chip or a modem) in the terminal, or by a device that includes the terminal functions. The functions of the RIS may also be performed by a module (such as a chip or a modem) in the RIS, or by a device that includes the RIS functions.

[0113] Referring to Figure 2, another system architecture diagram is shown. The channel between base station 110a and terminal 120a via RIS130 is channel 1, the channel between base station 110a and RIS130 is channel 2, the channel between base station 110a and terminal 120a is channel 3, the channel between RIS130 and terminal 120a is channel 4, the channel between RIS130 and terminal 120b is channel 5, the channel between RIS130 and terminal 120c is channel 6, the channel between base station 110a and terminal 120b via RIS130 is channel 7, the channel between base station 110a and terminal 120c via RIS130 is channel 8, and the channel between base station 110a and terminal 120b is channel 9. In the embodiment of the present application, the channels between two devices (such as channels 1 to 9) are physical transmission channels, rather than logical channels such as physical downlink control channels (PDCCHs) and physical downlink shared channels (PDSCHs).

[0114] 3 , in the related art, in a system using RIS to transmit signals between a base station and a terminal, the base station and the terminal perform steps S1 to S4 so that the base station obtains a precoding matrix for sending downlink data to the terminal.

[0115] S1. The base station sends a reference signal to the terminal.

[0116] S2. The terminal determines the channel state information of channel a based on the received reference signal.

[0117] S3. The terminal sends the channel state information of channel a and the request to increase the channel rank to the base station.

[0118] S4. The base station sends a reference signal to the terminal via RIS.

[0119] S5. The terminal determines the channel state information of channel b according to the received reference signal.

[0120] S6. The terminal sends the channel state information of channel b to the base station.

[0121] S7. The base station determines a precoding matrix based on the channel state information of channel a and the channel state information of channel b. The base station can determine the channel matrix of the channel based on the channel state information.

[0122] The base station can optimize the precoding matrix of the RIS and the precoding matrix on the base station side using the following formula 1 to obtain the maximum spectrum efficiency, or in other words, the maximum channel rank (rank for short).

[0123] Among them, H l,k =HBU l,k +αHBR l,k ΨHRU l,k W represents the precoding matrix of the base station, Ψ represents the precoding matrix of RIS, H l,k represents the channel matrix between the base station and the terminal and between the base station and the terminal through the RIS, l represents the index of the carrier carrying the reference signal, k represents the index of the terminal, HBU l,k Represents the channel matrix directly connected between the base station and the terminal, HBR l,k represents the channel matrix between the base station and RIS, HRU l,k represents the channel matrix between the RIS and the terminal, α represents the ratio of the large-scale fading of the signal from the base station to the terminal to the signal from the base station through the RIS to the terminal, and n represents the noise. α can be obtained from the following formula 2.

[0124] Referring to Figure 2 , it can be seen from Formula 1 above that, taking communication between base station 110a and terminal 120a as an example, to improve the system's spectral efficiency, it is necessary to know the channel matrix of channel 3 and the channel matrix of channel 1, or it is necessary to know the channel matrix of channel 3, the channel matrix of channel 2, and the channel matrix of channel 4. The channel matrix of channel 3 can be obtained using existing technologies, but the channel matrix of channel 1, or the channel matrices of channels 2 and 4, requires the base station to send a reference signal to the terminal via RIS to obtain it, resulting in additional overhead for estimating the channel matrix of channel 1, or estimating the channel matrices of channels 2 and 4.

[0125] To address the above issues, the present application proposes a communication method. Referring to Figure 4 , in this method, a terminal calculates its channel measurement status based on a first reference signal sent to the terminal by a base station via a RIS, and feeds back the terminal's channel measurement status to the base station. This allows the base station to determine whether it can independently determine the precoding matrix for the channel based on the terminal's channel measurement status. If the channel measurement status is a non-channel acquisition state, the base station can independently determine the precoding matrix for the channel. The terminal does not need to measure and report the channel state information for the channel to the base station, thereby reducing the energy consumption of the terminal used to measure the channel state information.

[0126] The following describes the communication method provided by the embodiment of the present application using FIG2 as an example. Referring to FIG5 , the process includes the following steps:

[0127] S501: A base station sends a first reference signal to a terminal via a RIS. Correspondingly, the terminal receives the first reference signal from the base station via the RIS.

[0128] The first reference signal can be a signal used to measure channels. For example, using Figure 2 as an example, base station 110a sends a first reference signal to terminal 120a via RIS 130. The first reference signal is a reference signal used to measure whether channel 4 is a line of sight (LOS) channel (or LOS path). The method for measuring whether channel 4 is an LOS channel can be described below. For another example, the first reference signal is a reference signal used to measure the channel state of a first channel. The terminal can measure the first reference signal to obtain channel state information of the first channel. The first channel is the channel between the base station and the terminal via the RIS. Referring to Figure 2, channel 1 can be the first channel mentioned above.

[0129] Exemplarily, the first reference signal may be at least one of the following downlink reference signals: a positioning reference signal (PRS), a channel state information reference signal (CSI-RS), or a demodulation reference signal (DMRS).

[0130] S502: The terminal sends first indication information to the base station according to the first reference signal. Correspondingly, the base station receives the first indication information from the terminal.

[0131] The first indication information is used to indicate a channel measurement state of the terminal. The channel measurement state of the terminal includes a non-channel acquisition state or a channel acquisition state.

[0132] In some embodiments, the terminal may determine the terminal's channel measurement status based on the relationship between the measurement result of the first reference signal and the first threshold. For specific implementation procedures, reference may be made to the descriptions of the subsequent related embodiments. The terminal may send first indication information indicating the terminal's channel measurement status to the base station.

[0133] In some embodiments, the first indication information may be carried in one or more of the following signaling: uplink control information (UCI), medium access control-command element (MAC-CE), and radio resource control (RRC).

[0134] In some embodiments, the channel acquisition state indicates that the terminal performs measurement on the first channel, and the non-channel acquisition state indicates that the terminal does not perform measurement on the first channel.

[0135] The terminal measuring the first channel may also be described as measuring the first channel, and the terminal not measuring the first channel may also be described as not measuring the first channel. For example, the terminal measuring the first channel may mean that the terminal determines the channel state information of the first channel based on a reference signal (such as the first reference signal and the second reference signal described below) transmitted via the first channel and sent by the base station. The terminal not measuring the first channel may mean that the terminal does not determine the channel state information of the first channel.

[0136] Exemplarily, the terminal sends first indication information to the base station, and the base station receives the first indication information. When the first indication information indicates that the channel measurement state of the terminal is the channel acquisition state, the channel acquisition state instructs the base station to send a second reference signal, and the base station can send the second reference signal to the terminal through the RIS. The terminal can measure the first channel based on the second reference signal, obtain the channel matrix of the first channel, and obtain the channel state information of the first channel based on the channel matrix of the first channel. The terminal sends the channel state information of the first channel to the base station. Accordingly, the base station receives the channel state information of the first channel from the terminal, determines the channel matrix of the first channel based on the channel state information of the first channel, and determines the precoding matrix of the first channel based on the channel matrix of the first channel.

[0137] In some embodiments, the base station may further send a second reference signal to the terminal via a direct channel with the terminal (such as channel 3 in Figure 2). After the terminal receives the second reference signal sent by the base station via channel 3, the terminal may determine the channel state information of the first channel based on the second reference signal transmitted via channel 3 and the second reference signal transmitted via the first channel.

[0138] The second reference signal is used by the terminal to determine channel state information of channel 1. For example, the second reference signal may be a CSI-RS.

[0139] When the first indication information indicates that the channel measurement state of the terminal is the non-channel acquisition state, the non-channel acquisition state indicates that the base station does not send the second reference signal to the terminal, and the base station may not send the second reference signal to the terminal. The terminal may not measure the first channel.

[0140] As another example, the channel acquisition state may further instruct the base station to receive channel state information obtained by the terminal measuring the first channel based on the first reference signal. As another example, the non-channel acquisition state may further instruct the base station not to receive channel state information obtained by the terminal measuring the first channel based on the first reference signal.

[0141] For example, the first reference signal is a CSI-RS. The terminal can determine channel state information of the first channel based on the first reference signal. When the terminal's channel measurement state is a channel acquisition state, the terminal can send the channel state information obtained by measuring the first channel based on the first reference signal to the base station. Correspondingly, the base station receives the channel state information obtained by the terminal by measuring the first channel based on the first reference signal.

[0142] The channel state information may include at least one of the following information: a precoding matrix indicator (PMI), a channel quality indicator (CQI), or a rank indication (RI).

[0143] It should be noted that the terminal may send the channel state information of the first channel through a direct connection channel with the base station (such as channel 3 in FIG2 ), or may send the channel state information of the first channel through the first channel.

[0144] Through the solution provided in the embodiments of the present application, when a terminal can measure the channel state information of a first channel based on a first reference signal, after receiving the first reference signal, the terminal sends first indication information based on the first reference signal. When the first indication information indicates that the channel measurement state of the terminal is a non-channel acquisition state, the base station can independently determine the precoding matrix of the channel, and the terminal does not need to measure the first channel, thereby saving resources consumed by the terminal in measuring the first channel.

[0145] In some cases, the terminal may not measure the channel state information of the first channel according to the first reference signal, for example, in the following cases 1 to 3.

[0146] Case 1: The first reference signal is a CSI-RS, and the number of first reference signals is insufficient for the terminal to determine the channel state information of the first channel based on the first reference signal. Exemplarily, the terminal requires at least M reference signals to measure and obtain the channel state information of the first channel, where M is a positive integer. The number of first reference signals sent by the base station is N, where N is less than M and is a positive integer.

[0147] For example, if the base station antenna has 64 transmit antenna elements and the frequency domain bandwidth used for measurement is 20 RBs (resource blocks), at least 64*20=1280 second reference signals need to be sent. The number of first reference signals is independent of the antennas and frequency domain bandwidth, but only depends on the number of beams scanned by the RIS. If the RIS has only 128 beams, the number of first reference signals is 128, which is much smaller than the number of second reference signals. In this case, M=1280 and N=128.

[0148] Case 2: The first reference signal is a reference signal such as PRS and DMRS.

[0149] Case 3: The first reference signal satisfies the terminal's requirements for measuring channel 1, but the terminal does not use the first reference signal to measure the channel state information of the first channel. For example, referring to Case 1, the first reference signal is a CSI-RS, where N is greater than or equal to M. In this case, the first reference signal satisfies the terminal's requirements for measuring the channel state information of the first channel, but the terminal only measures the first channel after providing feedback on the terminal's channel measurement status.

[0150] Through the solution provided by the embodiment of the present application, when the terminal does not determine the channel state information of the first channel based on the first reference signal, the terminal sends the first indication information based on the first reference signal after receiving the first reference signal. When the first indication information indicates that the channel measurement state of the terminal is a non-channel acquisition state, the base station can determine the precoding matrix of the first channel by itself, and the terminal does not need to measure the first channel, thereby saving the resources consumed by the terminal to measure the first channel. In addition, the base station no longer sends the second reference signal for measuring the channel state information of the first channel to the terminal through the RIS. For cases 1 and 2, when the number of first reference signals is less than the number of second reference signals, the occupation of air interface resources by the reference signal can be reduced. For case 2, when the first reference signal is a reference signal such as PRS, DMRS, etc., the base station can also determine the precoding matrix of the first channel, thereby increasing the scenario in which the base station determines the precoding matrix of the first channel and shortening the time for the base station to determine the precoding matrix of the first channel.

[0151] Furthermore, to achieve higher array gain, large-scale RIS arrays, such as those consisting of 1024 or more elements, are often used in practical scenarios. To achieve more precise phase control, common RIS architectures typically incorporate phase shifters behind each element. Since phase shifters require power, the RIS forwarding reference signals consumes significant power, which is a significant issue. By employing the methods of the present invention, the RIS no longer needs to forward the second reference signal, thereby reducing RIS energy consumption.

[0152] It should be noted that in the above embodiment, after measuring the first reference signal, the terminal reports the terminal's channel measurement status. In other embodiments, after measuring the first reference signal to obtain the terminal's channel measurement status, if the channel state information indicates a non-channel acquisition state, the terminal reports first indication information to the base station. If the channel state information indicates a channel acquisition state, the terminal does not report the first indication information to the base station. In this case, the first indication information indicates that the channel state information is in a non-channel acquisition state. Upon receiving the non-channel acquisition state, the base station may determine a precoding matrix for transmitting data to the terminal according to the method in the above embodiment. If the base station does not receive the first indication information, it may transmit a second reference signal for measuring channel state information and receive channel state information fed back by the terminal. Alternatively, it may receive a reference signal for measuring channel state information sent by the terminal and measure the channel state information. The base station then determines a precoding matrix for transmitting downlink data to the terminal based on the received channel state information. Consequently, when the terminal's channel state information indicates a channel acquisition state, the base station can obtain the terminal's channel state information without transmitting indication information to the base station, thereby conserving air interface resources.

[0153] In some embodiments, the first reference signal is a CSI-RS. The terminal can measure the first reference signal and the second reference signal to obtain channel state information for channel 1. For example, the terminal requires at least M reference signals to measure and obtain the channel state information of the first channel, where M is a positive integer. The number of first reference signals transmitted by the base station is N, where N is less than M. The number of second reference signals transmitted by the base station is Q, where Q is a positive integer and M−N ≤ Q ≤ M. Consequently, the base station no longer needs to transmit M reference signals to the terminal via the RIS, reducing the number of second reference signals transmitted by the base station and conserving air interface resources.

[0154] In some embodiments, the channel measurement status of the terminal is indicated by 1 bit. For example, 0 indicates a non-channel acquisition state, and 1 indicates a channel acquisition state. Through this solution, 1 bit is used to indicate the channel measurement status of the terminal, which occupies fewer bits than the channel status information sent by the terminal, and can save a large amount of air interface resources. Through this method, since the first indication information only needs to use 1 bit to indicate the channel measurement status of the terminal, fewer bits are required. Therefore, compared to the terminal feeding back the channel status information of the first channel to the network device after receiving multiple first reference signals, the present application can reduce the consumption of air interface resources by sending the first indication information. In addition, the resources consumed by the RIS due to forwarding the channel status information of the first channel are reduced.

[0155] In other embodiments, the terminal's channel measurement status is indicated using S bits, where S is a positive integer and is less than the number of bits occupied by the channel status information indicating the first channel. For example, 00 indicates a non-channel acquisition state, and 11 indicates a channel acquisition state. In this embodiment, indicating the terminal's channel measurement status using S bits can also conserve air interface resources.

[0156] It should be noted that the first reference signal and the second reference signal are reference signals used for measurement, and these two reference signals may also be referred to as pilot signals (pilot symbols).

[0157] In some embodiments, a configuration of the second reference signal is different from a configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and a pattern of the reference signal.

[0158] Exemplarily, the configuration of the second reference signal is different from the configuration of the first reference signal, including one or more of the following: the number of second reference signals is greater than the number of first reference signals, and the pattern of the second reference signal is different from the pattern of the first reference signal. Exemplarily, Figure 6A is a schematic diagram of the pattern of the first reference signal. Figure 6B is a schematic diagram of the pattern of the second reference signal. The horizontal axis is the time domain, and the unit is the transmission time interval (TTI). The vertical axis is the frequency domain, and the unit is the carrier. Each box represents a resource unit with a time domain of 1 TTI and a frequency domain of one carrier. The filled boxes in Figures 6A and 6B indicate that the first reference signal is transmitted on the resource unit. Figure 6B shows that the base station uses 4 antenna ports to send the second reference signal. The second reference signal sent by each antenna port uses a different filling pattern in the box.

[0159] The following describes how the terminal determines the channel measurement state of the terminal by measuring the first reference signal.

[0160] In some embodiments, after the above S501, the method further includes: the terminal measuring the first reference signal.

[0161] The channel measurement state of the terminal is determined according to the measurement result of the first reference signal.

[0162] In some embodiments, the terminal measures the first reference signal including: measuring at least one of the following indicators of the first reference signal: reference signal received power (RSRP), signal-to-noise ratio (SNR), reference signal received quality (RSRQ), reference signal received strength (RSSI), or delay power spectrum.

[0163] Exemplarily, there are multiple first reference signals, and the multiple first reference signals meet the following conditions, then the channel measurement state of the terminal is a non-channel acquisition state: there is a third reference signal among the multiple first reference signals, and the difference between the measured value of the indicator of the third reference signal and the measured value of the indicator of each first reference signal other than the third reference signal in the multiple first reference signals is greater than the first threshold.

[0164] Exemplarily, if the multiple first reference signals meet the following conditions, the channel measurement state of the terminal is the channel acquisition state: the third reference signal does not exist in the multiple first reference signals.

[0165] For example, referring to Figure 6C, the base station sends multiple first reference signals, reference signal 1 to reference signal 4, to the terminal via RIS. The terminal measures the delay power spectrum of reference signals 1 to 4, and obtains that the power peak of the delay power spectrum of reference signal 1 is the largest, with a power value of R watts, and the power peak of the delay power spectrum of reference signal 2 is the second largest, with a power value of S watts. The difference between the power peaks of the delay power spectrum of reference signal 1 and the delay power spectrum of reference signal 2 is RS, which is equal to T watts. Assuming that the first threshold is U watts, then T is greater than U, and the channel measurement state of the terminal is the non-channel acquisition state. Assuming that the first threshold is V watts, then T is less than V, and the channel measurement state of the terminal is the channel acquisition state. Wherein, R, S, T, U, and V are non-negative numbers. For example, R = 20, S = 8, T = 12, U = 10, and V = 15.

[0166] For another example, referring to FIG6D , base station 110a in FIG2 transmits beams 1 to 4 to terminal 120a via RIS 130. Beams 1 to 4 carry reference signals 1 to 4, respectively. The terminal measures RSRP for reference signals 1 to 4, and obtains the results shown in Table 1.

[0167] Table 1

[0168] Example 1: Assume that the RSRP value of Reference Signal 1 corresponding to Beam 1 is -130dBm, the RSRP value of Reference Signal 2 corresponding to Beam 2 is -100dBm, the RSRP value of Reference Signal 3 corresponding to Beam 3 is -128dBm, and the RSRP value of Reference Signal 4 corresponding to Beam 4 is -125dBm. Reference Signal 2 has the highest RSRP value, Reference Signal 4 has the second highest RSRP value, and the RSRP value of Reference Signal 4 differs by 25dB from the RSRP value of Reference Signal 2. Assuming the first threshold is 20dB, 25 is greater than 20, and the terminal's channel measurement state is non-channel acquisition.

[0169] Example 2: Assume that the RSRP value of Reference Signal 1 corresponding to Beam 1 is -100dBm, the RSRP value of Reference Signal 2 corresponding to Beam 2 is -130dBm, the RSRP value of Reference Signal 3 corresponding to Beam 3 is -128dBm, and the RSRP value of Reference Signal 4 corresponding to Beam 4 is -115dBm. Reference Signal 1 has the highest RSRP value, Reference Signal 4 has the second highest RSRP value, and the RSRP value of Reference Signal 4 differs by 15dB from the RSRP value of Reference Signal 2. Assuming the first threshold is 20dB, then 15 is greater than 20, and the terminal's channel measurement state is Channel Acquisition.

[0170] For another example, the terminal measures the SNRs of reference signals 1 to 4 and finds that reference signal 1 has the largest SNR value, WdB, and reference signal 2 has the second largest SNR value, XdB. The difference between the SNR values ​​of reference signal 1 and reference signal 2 is WX, which is equal to YdB. Assuming the first threshold is ZdB, then Y is greater than Z, and the terminal's channel measurement state is a non-channel acquisition state. Assuming the first threshold is AdB, then Y is less than A, and the terminal's channel measurement state is a channel acquisition state. Where W, X, Y, Z, and A are non-negative numbers. For example, W = 30, X = 5, Y = 25, Z = 20, and A = 29.

[0171] In some embodiments, the channel through which the first reference signal is transmitted from the RIS to the terminal is a Loss of Sight (LOS) channel, and the terminal's channel measurement state is a non-channel acquisition state; the channel through which the first reference signal is transmitted from the RIS to the terminal is a non-line of sight (NLOS) channel, and the terminal's channel measurement state is a channel acquisition state. For example, in the examples in Table 1 above, in Example 1, the channel from the RIS to the terminal is a Loss of Sight (LOS) channel. In Example 2, the channel from the RIS to the terminal is a NLOS channel.

[0172] For example, the terminal can determine whether the third reference signal exists among the multiple first reference signals using the above example to determine whether the channel through which the first reference signal is transmitted to the terminal via the RIS is a LOS channel or an NLOS channel. For example, if the third reference signal exists among the multiple first reference signals, the channel through which the first reference signal is transmitted to the terminal via the RIS is a LOS channel. For another example, if the third reference signal does not exist among the multiple first reference signals, the channel through which the first reference signal is transmitted to the terminal via the RIS is a NLOS channel.

[0173] In some embodiments, in addition to receiving channel state information of the first channel from the terminal and determining the precoding matrix (referred to as the first precoding matrix) used to send data through the first channel based on the channel state information, the base station can also calculate the precoding matrix used to send data through the first channel by other means. Examples of methods 1 and 2 are given below.

[0174] Mode 1: The base station determines the first precoding matrix through the first channel information.

[0175] The first precoding matrix is ​​the precoding matrix used by the base station to send data to the terminal via the RIS. The first channel information is the left singular vector matrix obtained by performing singular value decomposition (SVD) of the autocorrelation matrix of the second channel's channel matrix. The second channel is the channel between the base station and the RIS. Referring to Figure 2 , taking base station 110a and terminal 120a as an example, the second channel is channel 2.

[0176] Illustratively, a precoding matrix (referred to as precoding matrix 2 for short) used for sending data through the second channel can be obtained by performing SVD decomposition on the second channel, as shown in Formula 3.

[0177] Among them, H BS-RIS represents the channel matrix of the second channel, H BS-RIS H represents the transpose of the channel matrix of the second channel, U BS-RIS Indicates the first channel information, S BS-RIS is a diagonal matrix, The right singular vector matrix obtained after the autocorrelation matrix SVD of the channel matrix of the second channel is represented.

[0178] The first precoding matrix can be obtained by performing SVD decomposition on the first channel, as shown in Formula 4.

[0179] Among them, H BS-RIS represents the channel matrix of the second channel, M represents the number of antenna elements of the RIS, and N represents the number of antenna elements of the base station, that is, diag(H UE-RIS H UE-RIS H ) is the middle term, representing the vector H UE-RIS H UE-RIS H Diagonalize the matrix H. UE-RIS is the channel matrix between the terminal and the RIS, from a single antenna port of the terminal to the RIS, H UE-RIS A vector belonging to M rows and 1 column, that is H BS-RIS H U represents the transpose of the channel matrix of the second channel. BS-RIS Indicates the first channel information, S BS-RIS is a diagonal matrix, The right singular vector matrix obtained after the autocorrelation matrix SVD of the channel matrix of the second channel is represented.

[0180] From formula 3 and formula 4, we can see that if the middle term diag(H UE-RIS H UE-RIS H ) is a unit matrix with constant coefficients, then the first precoding matrix does not depend on the change of the third channel, where the third channel is the channel between the RIS and the terminal (channel 4 as shown in Figure 2). As shown in Formula 5: diag(H UE-RIS H UE-RIS H )=aI Formula 5

[0181] Where a is a constant and I is the unit matrix.

[0182] Therefore, when the channel between the RIS and the terminal is a Loss of Sight (LOS) channel, the base station can determine the first precoding matrix based on the first channel information. For example, base station 110a communicating with terminal 120a via RIS 130, as shown in Figure 2, is shown in Figure 7A. This shows the correlation of precoding matrix U for base stations using channels 2 and 1. The horizontal axis represents the correlation of the precoding matrices, and the vertical axis represents the cumulative distribution function (CDF) of the correlation. It can be seen that when channel 4 is a Loss of Sight (LOS) channel, the correlation between channels 2 and 1 is above 97%, close to 1. When channel 4 is an NLOS path, the correlation between channels 2 and 1 is above 70%.

[0183] With the above solution, the base station can determine the precoding matrix used by base station 110a to transmit signals to terminal 120a via the RIS using the left singular vector matrix obtained after SVD decomposition of the channel matrix for channel 2. This eliminates the need for the base station to transmit a large number of second reference signals to terminal 120a via the RIS to measure the precoding matrix for channel 1, thereby conserving air interface resources occupied by the second reference signals. Furthermore, this reduces the energy consumed by the RIS in forwarding the second reference signals.

[0184] In other embodiments, when the base station receives a signal indicating that the terminal's channel measurement state is in the channel acquisition state, the base station also uses the first or third precoding matrix to transmit data. Referring to Figure 7A , when the terminal's channel measurement state is in the channel acquisition state, or when channel 4 from the RIS to the terminal is an NLOS channel, the correlation between channel 2 and channel 1 is greater than 70%. While this channel correlation is low, it still exhibits a certain degree of correlation. This saves air interface resources consumed by transmitting the second reference signal.

[0185] Mode 2: The base station determines the first precoding matrix through the second channel information.

[0186] The second channel information is a left singular vector matrix obtained by performing SVD decomposition of the autocorrelation matrix of the product of the channel matrix of the third channel and the channel matrix of the second channel. The third channel is a channel between the RIS and the terminal.

[0187] The product G of the channel matrix of the third channel and the channel matrix of the second channel can be expressed as G=H BS-RIS diag(H UE-RIS ), where H BS-RIS represents the channel matrix of the second channel, diag(H UE-RIS ) represents the vector H UE-RISDiagonalize the matrix of GG. H =H BS-RIS diag(H UE-RIS )(H BS-RIS diag(H UE-RIS )) H Formula 6

[0188] Perform SVD decomposition on GGH, as shown in Formula 7. svd(GG H )=U G ,S G ,V G Formula 7

[0189] According to formula 5 and formula 7, we can get U G ≈U BS-RIS .

[0190] Therefore, it can be seen that, similar to method 1, when channel 4 is a LOS channel, the base station can determine the second channel information by the product G of the channel matrix of the third channel and the channel matrix of the second channel, and thus determine the first precoding matrix based on the second channel information.

[0191] In this way, the base station can determine the base station precoding matrix required for signal propagation along the path without sending a reference signal to the terminal via the RIS. This saves air interface resources consumed by sending reference signals and reduces the delay in obtaining the precoding matrix.

[0192] In addition, in a scenario where there is only one communication path between the base station and the terminal, that is, there is no direct channel between the base station and the terminal, the base station can directly use the first precoding matrix to precode the data sent to the terminal, that is, send data to the terminal through the first precoding matrix.

[0193] For example, in Figure 2, base station 110a and terminal 120b communicate with terminal 120c via channel 8 (or, alternatively, channel 2 and channel 6). Base station 110a can determine a first precoding matrix based on first channel information or second channel information. In this case, the base station only needs to send a small amount of reference signal to determine the precoding matrix for RIS 130, adjust the RIS, forward data to terminal 120c, and transmit data to terminal 120b using the first precoding matrix.

[0194] In some embodiments, a communication path exists between the base station and the terminal that does not require a RIS, such as channels 3 and 9 shown in Figure 2. In this case, the precoding matrix used by the base station to transmit data to the terminal may also consider a path where the base station directly transmits data to the terminal. Based on this, and referring to Figure 8 , an embodiment of the present application further provides a communication method, including steps S801 to S803.

[0195] S801: A base station sends a first reference signal to a first terminal via a RIS. Correspondingly, the first terminal receives the first reference signal from the base station via the RIS.

[0196] S802: The first terminal sends first indication information to the base station according to the first reference signal. Correspondingly, the base station receives the first indication information from the first terminal.

[0197] In some embodiments, if the first indication information indicates that the channel measurement state of the first terminal is a non-channel acquisition state, the base station may obtain the first precoding matrix according to the above example.

[0198] In some embodiments, if the first indication information indicates that the channel measurement state of the first terminal is a channel acquisition state, the base station may send a second reference signal. The first terminal measures the second reference signal to obtain channel state information. The first terminal sends the channel state information to the base station. The base station receives the channel state information. The base station determines a first precoding matrix based on the channel state information.

[0199] It should be noted that the relevant descriptions of S801 and S802 can refer to the above-mentioned S501 and S502 and are not repeated here.

[0200] S803. The base station sends data to the first terminal using a third precoding matrix.

[0201] The third precoding matrix is ​​determined based on the first precoding matrix and the second precoding matrix. The first precoding matrix is ​​the precoding matrix used by the base station to send data to the first terminal via the RIS. The second precoding matrix is ​​the precoding matrix used by the base station to send data to the first terminal via a direct channel with the first terminal.

[0202] For example, referring to Figure 2 , base station 110a uses the third precoding matrix to transmit data to terminal 120a. Base station 110a can transmit data to terminal 120a using the following two links: a direct link (or a direct channel) between base station 110a and terminal 120a, and a link between base station 110a and terminal 120a via RIS 130. Referring to Formulas 8 and 9, base station 110a can determine the precoding matrix used by the base station to simultaneously transmit data to terminal 120a using both links by respectively obtaining the precoding matrices corresponding to the two links (the first precoding matrix and the second precoding matrix).

[0203] in, represents obtaining a second precoding matrix for transmitting data via a direct channel between the base station and the first terminal, W dir represents the second precoding matrix. represents obtaining a first precoding matrix for transmitting data using a cascade link between the base station and the first terminal via the RIS, W ris represents the first precoding matrix, Ψ represents the precoding matrix of RIS, l represents the index of the carrier carrying the reference signal, k represents the index of the first terminal, HBU l,k represents the channel matrix directly connected between the base station and the first terminal, HBR l,k represents the channel matrix between the base station and RIS, HRU l,k represents the channel matrix between the RIS and the first terminal, and n1 and n2 represent noise.

[0204] W is obtained by the above formula 8 and formula 9 ris and W dir After that, the base station can eliminate W by using methods such as zero forcing algorithm, null space projection algorithm, alternating direction method of multipliers (ADMM), etc. ris and W dir The interference in the two links is obtained to obtain the precoding matrix W used to send data to the first terminal simultaneously. For example, using the zero-forcing algorithm as an example, W can be obtained by referring to Formula 10. W = [W dir W ris ]([W dir W ris ] H [W dir W ris ]) -1 Formula 10

[0205] in,[] HIndicates transposition, () -1 Represents the inverse matrix.

[0206] When the precoding matrix of the cascaded links between the base station and multiple terminals through the same RIS is the same, W ris It can represent the precoding matrix of the cascade link between the base station and the above-mentioned multiple terminals through the RIS. For example, referring to Figure 2, W ris It may represent a precoding matrix between the base station 110a and the terminal 120a via the RIS 130, a precoding matrix between the base station 110a and the terminal 120b via the RIS 130, or a precoding matrix between the base station 110a and the terminal 120c via the RIS 130.

[0207] Therefore, the third precoding matrix W1 between the base station 110a and the terminal 120a can refer to formula 11, and the fifth precoding matrix W2 between the base station 110a and the terminal 120b can refer to formula 12. dir,1 W ris ]([W dir,1 W ris ] H [W dir,1 W ris ]) -1 Formula 11 W2=[W dir,2 W ris ]([W dir,2 W ris ] H [W dir,2 W ris ]) -1 Formula 12

[0208] Among them, W dir,1 represents the second precoding matrix of the direct link between the base station 110a and the terminal 120a, W dir,2 represents a fourth precoding matrix for the direct link between the base station 110a and the terminal 120b.

[0209] In some embodiments, the channel measurement state of the second terminal is a non-channel acquisition state, and the above method further includes S804.

[0210] S804. The base station sends data to the second terminal using the fifth precoding matrix.

[0211] The fifth precoding matrix is ​​determined based on the first precoding matrix and the fourth precoding matrix. The fourth precoding matrix is ​​a precoding matrix used by the base station to send data to the second terminal through the first device. Exemplarily, the second terminal is terminal 120b in Figure 2.

[0212] When the precoding matrix for the cascaded links between a base station and multiple terminals via RIS is the same, the base station can determine the precoding matrix for the cascaded link between the base station and the terminal via RIS based on the precoding matrix already obtained for the cascaded links between the base station and the other terminals via RIS or a predefined precoding matrix. Consequently, the base station no longer needs to calculate the second precoding matrix for each terminal's link with the base station via RIS. Instead, it only needs to calculate the second precoding matrix for the direct link between the terminal and the base station. This reduces the base station's energy consumption when calculating the total precoding matrix W for the link between the terminal and the base station. Furthermore, the base station does not need to send the second reference signal used to calculate the second precoding matrix to the terminal via RIS, consuming fewer air interface resources.

[0213] It should be noted that in the above embodiments, when the channel measurement state of the terminal is in the non-channel acquisition state, the base station can determine the first precoding matrix based on the first channel information or the second channel information, and send data to the terminal using the first precoding matrix. Alternatively, the base station can further determine the third precoding matrix based on the first precoding matrix and the second precoding matrix, and send data to the terminal using the third precoding matrix. In other embodiments, the base station may not receive the channel measurement state of the terminal and directly use the first precoding matrix or the third precoding matrix to send data.

[0214] Refer to Figures 7B and 7C. Figure 7B is a simulation diagram of rank improvement in a single-user (SU) scenario. Figure 7C is a simulation diagram of rank improvement in a multi-user (MU) scenario. It can be seen that in the SU scenario: under 0dB noise, the rank of the terminal increases from 2 streams to 4 streams using the method provided in the embodiment of the present application. Under 10dB noise, the rank of the terminal increases from 5 streams to 6 streams using the method provided in the embodiment of the present application. Under 20dB noise, the rank of the terminal remains at 6 streams. In the MU scenario: under 10dB noise, the rank of 3 terminals increases from 12 streams to 15 streams using the method provided in the embodiment of the present application. Under 20dB noise, the rank of the 3 terminals does not change.

[0215] Referring to Figure 7D, which is a simulation diagram of spectrum efficiency in the MU scenario, it can be seen that compared with the traditional solution of using RIS to improve spectrum efficiency, the communication method provided in the embodiment of the present application has a 3%-10% loss in spectrum efficiency of the obtained precoding codebook, but it saves a large amount of air interface resources.

[0216] The air interface overhead gain of the communication method provided in the embodiment of the present application is as follows: Assuming that there are B terminals served by the same RIS, the air interface resource overhead of the CSI measurement of a single terminal is K, and the UE ratio of the LOS path among all UEs is P, then the air interface gain O compared to the traditional solution can refer to Formula 13.

[0217] In some embodiments, the embodiment of the present application further includes: the terminal sends second indication information, and correspondingly, the base station receives the second indication information.

[0218] The second indication information indicates an identifier of the fourth reference signal.

[0219] Exemplarily, the fourth reference signal is a reference signal with the best index among the plurality of first reference signals. The number of the fourth reference signals may be one or more.

[0220] For example, when the number of fourth reference signals is one, the fourth reference signal may be a signal with a maximum RSRP value, a signal with a maximum SNR, a signal with a maximum RSRQ, or a signal with a maximum RSSI. For another example, referring to Table 1, an example of the fourth reference signal may be reference signal 2 corresponding to beam 2 in Example 1 above, or reference signal 1 corresponding to beam 1 in Example 2 above.

[0221] It can be understood that when the channel measurement state of the terminal is a non-channel acquisition state, the third reference signal can be used as the fourth reference signal.

[0222] For another example, when there are multiple fourth reference signals, the multiple fourth reference signals may be multiple reference signals with the best performance among the first reference signals. For example, when there are two fourth reference signals, referring to Table 1, an example of the fourth reference signal may be reference signal 2 corresponding to beam 2 and reference signal 4 corresponding to beam 4 in Example 1, or reference signal 1 corresponding to beam 1 and reference signal 4 corresponding to beam 4 in Example 2.

[0223] In some embodiments, the second indication information includes one or more of the following information: an identifier of the first beam, a time slot of the first beam, a frequency domain position of the first beam, an identifier of the fourth reference signal, or an identifier of the precoding of the first beam, wherein the first beam is a beam carrying the fourth reference signal.

[0224] Exemplarily, before sending a beam to the terminal, the base station may pre-configure the scanning order of the beam, the scanning time slot of the beam, the frequency domain position of the beam (referring to the carrier on which the signal is sent), etc. to the terminal. When the terminal receives the reference signal, the terminal can determine the beam corresponding to the reference signal based on one or more information such as the order in which the reference signal is received, the time slot in which the reference signal is received, or the frequency domain position in which the reference signal is received, thereby indicating it to the base station in the second indication information. For example, the base station scans beams 1 to 4 in sequence. Among the four reference signals received by the terminal, the third reference signal is the reference signal with the best indicator, that is, the fourth reference signal mentioned above. The terminal can determine that the reference signal is the reference signal carried on beam 3 based on the order in which the reference signal is received. The identifier of beam 3 is sent in the second indication information.

[0225] The identifier can be identified by an index. For example, the identifier of the first beam can be determined by the index of the first beam. For another example, the identifier of the fourth reference signal can be determined by the index of the fourth reference signal.

[0226] With this solution, the terminal sends the identifier of the fourth reference signal to the base station. The base station can use the identifier of the fourth reference signal to determine the direction in which the RIS forwards data to the terminal, thereby determining Ψ in Formula 9. This improves communication between the base station and the terminal. When the RIS forwards data to different terminals, the base station can determine the beam direction of the RIS when forwarding data to the terminal based on the second indication information fed back by the terminal.

[0227] It should be noted that, similar to the terminal sending the first indication information, the terminal can send the second indication information to the base station through RIS, or directly to the base station without RIS, or through both paths.

[0228] 9 , which is an example of a communication method provided in an embodiment of the present application, the method includes S901 - S908 .

[0229] S901. A base station calculates a sixth precoding matrix according to a channel between the base station and a RIS or a channel between the base station and a fourth terminal through the RIS.

[0230] Exemplarily, the base station may calculate the sixth precoding matrix using the solution of the above embodiment, such as the method 1 and method 2 provided in the example in which the base station calculates the precoding matrix of the first channel using other methods. The channel between the fourth terminal and the RIS is a LOS channel.

[0231] As another example, the base station may determine the sixth precoding matrix through sensing technology and artificial intelligence (AI) technology.

[0232] S902: The base station sends a fifth reference signal to the first terminal. Correspondingly, the first terminal receives the fifth reference signal from the base station.

[0233] Exemplarily, the fifth reference signal is a CSI-RS. The fifth reference signal is used to measure a channel between the base station and the first terminal. For example, referring to FIG2 , the base station 110a sends the fifth reference signal to the terminal 120a to measure channel 3.

[0234] S903: The first terminal sends channel state information and / or spectrum efficiency enhancement requirements to the base station. Correspondingly, the base station receives the channel state information and / or spectrum efficiency enhancement requirements from the first terminal.

[0235] Exemplarily, the first terminal measures the fourth reference signal to obtain channel state information of channel 9, and sends the channel state information of channel 9. The first terminal may determine that the spectral efficiency needs to be enhanced by 20% based on the measured channel state information of channel 9.

[0236] It should be noted that the first terminal can realize the transmission spectrum efficiency enhancement requirement by sending the channel rank enhancement requirement to the base station.

[0237] For example, the first terminal may send the level of the channel rank enhancement requirement (e.g., level 1, level 2, level 3, etc.) to the base station, so that the base station allocates different numbers of RISs to the first terminal based on the level of the channel rank enhancement requirement. For example, if the channel rank enhancement requirement is level 1, one RIS is allocated to the terminal, and the subsequent terminal uses this RIS to forward data to the first terminal. If the channel rank enhancement requirement is level 2, three RISs are allocated to the terminal. If the channel rank enhancement requirement is level 3, five RISs are allocated to the terminal.

[0238] As another example, the channel rank enhancement request sent by the first terminal to the base station is an amount by which the channel rank needs to be increased. For example, the channel rank enhancement request sent by the first terminal to the base station is an amount by which the channel rank needs to be increased by 2. The base station may determine the number of RISs to allocate to the first terminal based on the amount by which the channel rank needs to be increased and / or determine the selected RIS based on the position of the RIS.

[0239] S904: The base station sends a first reference signal to the first terminal via the RIS. Correspondingly, the first terminal receives the first reference signal via the RIS.

[0240] For example, S904 may refer to the relevant description of S501.

[0241] In some embodiments, the base station may determine whether to send the first reference signal to the first terminal based on the channel state information and / or the spectrum efficiency enhancement requirement. For example, if there is a spectrum efficiency enhancement requirement, S904 is executed.

[0242] S905: The first terminal measures a first reference signal, and determines a channel measurement state of the first terminal according to the first reference signal.

[0243] S905 may refer to the above description of the terminal measuring the first reference signal.

[0244] S906: The first terminal sends first indication information and second indication information to the base station. Correspondingly, the base station receives the first indication information and second indication information from the first terminal.

[0245] For the related description of S906 , reference may be made to the related description of the terminal sending the first indication information and the terminal sending the second indication information.

[0246] S907. The base station determines a precoding matrix for sending data to the first terminal according to the first indication information and the second indication information.

[0247] The base station performs precoding configuration for communicating with the first device through the RIS according to the seventh precoding matrix and the beam indicated by the second indication information.

[0248] Exemplarily, the first indication information indicates that the channel measurement state of the first terminal is non-channel acquisition state, and the base station can use the sixth precoding matrix determined in S901 as the seventh precoding matrix for transmitting data between the base station and the first terminal through the RIS.

[0249] As another example, the first indication information indicates that the channel measurement state of the first terminal is a channel acquisition state. The base station may refer to the step of sending the second reference signal to the terminal via the RIS in the above embodiment. After sending the second reference signal to the first terminal via the RIS, the base station receives channel state information sent by the first terminal, and determines, based on the received channel state information, a seventh precoding matrix for transmitting data between the RIS and the first terminal.

[0250] As another example, the first indication information indicates that the channel measurement state of the first terminal is a channel acquisition state. The first terminal may send an uplink reference signal to the base station for measuring the channel state information transmitted via the RIS to the base station. The base station receives and measures the uplink reference signal to obtain channel state information. The seventh precoding matrix is ​​then determined based on the channel state information.

[0251] Exemplarily, the uplink reference signal may be a sounding reference signal (SRS).

[0252] S908: The base station sends downlink data to the first terminal. Correspondingly, the first terminal receives the downlink data sent by the base station.

[0253] The base station sends downlink data to the first terminal using the precoding configuration determined in S907.

[0254] With this solution, a first terminal can determine its own channel measurement status by measuring the first reference signal and report the channel measurement status. When the channel measurement status is not in the channel acquisition state, the base station may not send the second reference signal used to measure channel state information to the terminal, thereby reducing the air interface resources and latency overhead consumed by measuring the second reference signal and improving system performance.

[0255] When a base station transmits signals to multiple terminals via the same RIS, if the channel measurement states of the multiple terminals are all in a non-channel measurement state, the base station can reuse the precoding matrices of the links used by the multiple terminals to communicate with the base station via the RIS, eliminating the need to calculate a separate precoding matrix for each terminal, thereby reducing the computational overhead of the base station. Referring to FIG10 , FIG10 is another example of a communication method provided in an embodiment of the present application, the method comprising the following steps.

[0256] S1001. A base station calculates a sixth precoding matrix according to a channel between the base station and a RIS or a channel between the base station and a fourth terminal through the RIS.

[0257] The specific implementation of S1001 may refer to S901.

[0258] S1002: The base station sends a fifth reference signal to the first terminal. Correspondingly, the first terminal receives the fifth reference signal from the base station.

[0259] S1012: The base station sends a sixth reference signal to the second terminal. Correspondingly, the second terminal receives the sixth reference signal from the base station.

[0260] The specific implementation of S1002 and S1012 may refer to S902.

[0261] S1003: The first terminal sends its channel state information and / or spectrum efficiency enhancement requirement to the base station. Correspondingly, the base station receives its channel state information and / or spectrum efficiency enhancement requirement from the first terminal.

[0262] S1013: The second terminal sends its channel state information and / or spectrum efficiency enhancement requirement to the base station. Correspondingly, the base station receives its channel state information and / or spectrum efficiency enhancement requirement from the second terminal.

[0263] The specific implementation of S1003 and S1013 may refer to S903.

[0264] S1004: The base station sends a first reference signal to the first terminal via the RIS. Correspondingly, the first terminal receives the first reference signal via the RIS.

[0265] S1014: The base station sends a first reference signal to the second terminal via the RIS. Correspondingly, the second terminal receives the first reference signal via the RIS.

[0266] The specific implementation of S1004 and S1014 may refer to S904.

[0267] S1005: The first terminal measures a first reference signal, and determines a channel measurement state of the first terminal according to the first reference signal.

[0268] S1015. The second terminal measures the first reference signal, and determines a channel measurement state of the second terminal according to the first reference signal.

[0269] The specific implementation of S1005 and S1015 may refer to S905.

[0270] S1006: The first terminal sends first indication information and second indication information to the base station. Correspondingly, the base station receives the first indication information and second indication information from the first terminal.

[0271] S1016: The second terminal sends first indication information and second indication information to the base station. Correspondingly, the base station receives the first indication information and second indication information from the second terminal.

[0272] The specific implementation of S1006 and S1016 may refer to S906.

[0273] S1007. The base station determines a precoding matrix for sending data to the first terminal according to the first indication information and the second indication information from the first terminal.

[0274] S1017. The base station determines a precoding matrix for sending data to the second terminal according to the first indication information and the second indication information from the second terminal.

[0275] The specific implementation of S1007 and S1017 may refer to S907.

[0276] S1008: The base station sends downlink data to the first terminal in the first time slot. Correspondingly, the first terminal receives the downlink data sent by the base station.

[0277] S1018: The base station sends downlink data to the second terminal in the second time slot. Correspondingly, the second terminal receives the downlink data sent by the base station.

[0278] The specific implementation of S1008 and S1018 may refer to S908.

[0279] In some embodiments, the first time slot and the second time slot are different.

[0280] In the various embodiments of the present application, unless otherwise specified or logically conflicting, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships. For example, the above-mentioned multiple embodiments can be combined, and the combined scheme can be implemented. Optionally, some operations in the process of each method embodiment are optionally combined, and / or the order of some operations is optionally changed. In addition, the execution order between the steps of each process is only exemplary and does not constitute a limitation on the execution order between the steps. Other execution orders can also be used between the steps. It is not intended to indicate that the execution order is the only order in which these operations can be performed. Ordinary technicians in this field will think of various ways to reorder the operations in this article. In addition, it should be noted that the process details involved in a certain embodiment of this article are also applicable to other embodiments in a similar manner, or different embodiments can be used in combination.

[0281] It is understood that, in order to implement the functions in the above embodiments, the base station and the terminal include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in conjunction with the units and method steps of the various examples described in the embodiments disclosed in this application, this application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0282] Figures 11 and 12 are schematic diagrams of the structures of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal or base station in the above method embodiments, and thus can also achieve the beneficial effects possessed by the above method embodiments. In the embodiments of the present application, the communication device can be the terminal 120 as shown in Figure 1, or the base station 110 as shown in Figure 1, or a module (such as a chip) applied to a terminal or base station.

[0283] As shown in Figure 11, the communication device 1300 includes a processing unit 1310 and a transceiver unit 1320. The communication device 1300 is used to implement the functions of the terminal or base station in the method embodiments shown in Figures 5, 8, 9 or 10 above.

[0284] When the communication device 1300 is used to implement the functions of the terminal in the method embodiment shown in Figure 5: the transceiver unit 1320 is used to receive the first reference signal sent by the base station through the RIS and send first indication information to the base station based on the first reference signal; the processing unit 1310 is used to perform processing-related functions.

[0285] When the communication device 1300 is used to implement the functions of the base station in the method embodiment shown in FIG5 , the transceiver unit 1320 is used to send the first reference signal to the terminal and receive the first indication information through the RIS; the processing unit 1310 is used to perform processing-related functions.

[0286] When the communication device 1300 is used to implement the functions of the base station in the method embodiment shown in Figure 8: the transceiver unit 1320 is further used to send data to the terminal through the third precoding matrix; and the processing unit 1310 is used to perform processing-related functions.

[0287] For a more detailed description of the processing unit 1310 and the transceiver unit 1320 , please refer to the relevant description in the method embodiments shown in FIG. 5 , FIG. 8 , FIG. 9 or FIG. 10 .

[0288] As shown in Figure 12, communication device 1400 includes a processor 1410 and an interface circuit 1420. Processor 1410 and interface circuit 1420 are coupled to each other. It is understood that interface circuit 1420 can be a transceiver or an input / output interface. Optionally, communication device 1400 may also include a memory 1430 for storing instructions executed by processor 1410, input data required by processor 1410 to execute instructions, or data generated after processor 1410 executes instructions.

[0289] When the communication device 1400 is used to implement the method shown in FIG. 5 , the processor 1410 is used to implement the functions of the processing unit 1310 , and the interface circuit 1420 is used to implement the functions of the transceiver unit 1320 .

[0290] When the above-mentioned communication device is a chip applied to a terminal, the terminal chip implements the functions of the terminal in the above-mentioned method embodiment. When the terminal chip receives information from the base station, it can be understood that the information is first received by other modules in the terminal (such as a radio frequency module or antenna) and then sent to the terminal chip by these modules. When the terminal chip sends information to the base station, it can be understood that the information is first sent to other modules in the terminal (such as a radio frequency module or antenna) and then sent to the base station by these modules.

[0291] When the above-mentioned communication device is a chip applied to a base station, the base station chip implements the functions of the base station in the above-mentioned method embodiment. When the base station chip receives information from the terminal, it can be understood that the information is first received by other modules in the base station (such as a radio frequency module or antenna) and then sent to the base station chip by these modules. When the base station chip sends information to the terminal, it can be understood that the information is sent to other modules in the base station (such as a radio frequency module or antenna) and then sent to the terminal by these modules.

[0292] In this application, when entity A sends information to entity B, it can be done directly from A to B or indirectly through another entity. Similarly, when entity B receives information from entity A, it can be done directly from entity B or indirectly through another entity. Entities A and B herein can be RAN nodes or terminals, or modules within a RAN node or terminal. The sending and receiving of information can be information exchange between a RAN node and a terminal, for example, between a base station and a terminal; the sending and receiving of information can also be information exchange between two RAN nodes, for example, between a CU and a DU; the sending and receiving of information can also be information exchange between different modules within a device, for example, between a terminal chip and other modules in the terminal, or between a base station chip and other modules within the base station.

[0293] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0294] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and storage medium can also exist in a base station or a terminal as discrete components.

[0295] Optionally, the present application also provides a computer program product. All or part of the processes in the above method embodiments may be completed by a computer program instructing related hardware. The program may be stored in the above computer program product, and when executed, the program may include the processes in the above method embodiments.

[0296] Optionally, the present application also provides a computer instruction. All or part of the process in the above method embodiment can be completed by the computer instruction to instruct the relevant hardware (such as a computer, processor, wireless relay device, terminal or RAN node, etc.). The program can be stored in the above computer-readable storage medium or in the above computer program product.

[0297] Optionally, the present application also provides a communication system, including: the RAN node and IRS in the above embodiment.

[0298] Optionally, the system also includes the terminal in the above practical example.

[0299] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

Claims

1. A communication method, characterized in that: include: receiving, by the first device, a first reference signal from a network device; According to the first reference signal, first indication information is sent, where the first indication information is used to indicate a channel measurement status of the terminal; the channel measurement status of the terminal includes a non-channel acquisition state or a channel acquisition state, the channel acquisition state indicates that the terminal measures a first channel, and the non-channel acquisition state indicates that the terminal does not measure the first channel, where the first channel is a channel between the network device and the terminal through the first device.

2. The method according to claim 1, characterized in that The channel measurement status of the terminal is indicated by 1 bit.

3. The method according to claim 1 or 2, characterized in that The channel measurement state of the terminal is a channel acquisition state. After sending the first indication information, the method further includes: receiving, by the first device, a second reference signal from the network device; The terminal measures the first channel, including: the terminal measures the second reference signal to obtain channel state information of the first channel; the method further includes: sending the channel state information of the first channel.

4. The method according to claim 3, characterized in that The configuration of the second reference signal is different from the configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and a pattern of the reference signal.

5. The method according to claim 4, characterized in that The configuration of the second reference signal is different from that of the first reference signal, including one or more of the following: the number of the second reference signals is greater than the number of the first reference signals, and the pattern of the second reference signal is different from that of the first reference signal.

6. The method according to any one of claims 1 to 5, characterized in that After receiving the first reference signal from the network device through the first device, the method further includes: The first reference signal is measured, and a channel measurement state of the terminal is determined according to a measurement result of the first reference signal.

7. The method according to claim 6, characterized in that The measuring of the first reference signal includes: measuring at least one of the following indicators of the first reference signal: reference signal received power RSRP, signal-to-noise ratio SNR, reference signal received quality RSRQ, reference signal received intensity RSSI or delay power spectrum.

8. The method according to any one of claims 1 to 7, characterized in that There are multiple first reference signals, and the multiple first reference signals meet the following conditions, then the channel measurement state of the terminal is a non-channel acquisition state: there is a third reference signal among the multiple first reference signals, and a difference between a measured value of an indicator of the third reference signal and a measured value of an indicator of each first reference signal other than the third reference signal in the multiple first reference signals is greater than a first threshold; If the multiple first reference signals meet the following condition, the channel measurement state of the terminal is a channel acquisition state: the third reference signal does not exist in the multiple first reference signals.

9. The method according to any one of claims 1 to 8, characterized in that The channel through which the first reference signal passes from the first device to the terminal is a line-of-sight LOS channel, and the channel measurement state of the terminal is a non-channel acquisition state; the channel through which the first reference signal passes from the first device to the terminal is a non-line-of-sight NLOS channel, and the channel measurement state of the terminal is a channel acquisition state.

10. A communication method, characterized in that: include: Sending a first reference signal to the first terminal through the first device; Receive first indication information, where the first indication information is used to indicate a channel measurement status of the first terminal; the channel measurement status of the first terminal includes a non-channel acquisition state or a channel acquisition state, where the channel acquisition state indicates that the network device sends a second reference signal, and the non-channel acquisition state indicates that the network device does not send the second reference signal, where the second reference signal is used by the first terminal to measure a first channel, where the first channel is a channel between the network device and the first terminal through the first device.

11. The method according to claim 10, characterized in that The channel measurement status of the first terminal is indicated by one bit.

12. The method according to claim 10 or 11, characterized in that The channel measurement state of the first terminal is a channel acquisition state, and the method further includes: Sending a second reference signal to the first terminal through the first device; Channel state information of the first channel is received.

13. The method according to claim 12, characterized in that The configuration of the second reference signal is different from the configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and a pattern of the reference signal.

14. The method according to claim 13, characterized in that The configuration of the second reference signal is different from that of the first reference signal, including one or more of the following: the number of the second reference signals is greater than the number of the first reference signals, and the pattern of the second reference signal is different from that of the first reference signal.

15. The method according to any one of claims 10 to 14, characterized in that: The channel measurement state of the first terminal is a non-channel acquisition state, and the method further includes: A first precoding matrix is determined through first channel information or second channel information, where the first precoding matrix is a precoding matrix used by the network device to send data to the first terminal through the first device, the first channel information is a left singular vector matrix obtained by SVD decomposition of the autocorrelation matrix of the channel matrix of the second channel, and the second channel information is a left singular vector matrix obtained by SVD decomposition of the autocorrelation matrix of the product of the channel matrix of the third channel and the channel matrix of the second channel, the second channel is a channel between the network device and the first device, and the third channel is a channel between the first device and the first terminal.

16. The method according to claim 15, characterized in that The channel measurement state of the first terminal is a non-channel acquisition state, and the method further includes: Data is sent to the first terminal through a third precoding matrix; the third precoding matrix is determined based on the first precoding matrix and the second precoding matrix, and the second precoding matrix is the precoding matrix used by the network device to send data to the first terminal.

17. The method according to claim 15 or 16, characterized in that The method further comprises: Data is sent to the second terminal through the fifth precoding matrix; the channel measurement state of the second terminal is a non-channel acquisition state, the fifth precoding matrix is determined based on the first precoding matrix and the fourth precoding matrix, and the fourth precoding matrix is the precoding matrix used by the network device to send data to the second terminal through the first device.

18. A communication method, characterized in that: include: Sending a first reference signal to the first terminal through the first device; Receive first indication information, where the first indication information is used to indicate a channel measurement status of a first terminal; the channel measurement status of the first terminal includes a non-channel acquisition state or a channel acquisition state, where the channel acquisition state indicates that the network device receives channel status information obtained by the first terminal measuring the first channel for a first reference signal, and the non-channel acquisition state indicates that the network device does not receive channel status information obtained by the first terminal measuring the first channel for a first reference signal, where the first channel is a channel between the network device and the first terminal through the first device.

19. The method according to claim 18, characterized in that The channel measurement status of the first terminal is indicated by one bit.

20. The method according to claim 18 or 19, characterized in that The channel measurement state of the first terminal is a channel acquisition state, and the method further includes: sending, by the first device, a second reference signal to the first terminal, where the second reference signal is used by the first terminal to measure the first channel; Channel state information of the first channel is received.

21. The method according to claim 20, characterized in that The configuration of the second reference signal is different from the configuration of the first reference signal, and the configuration of the reference signal includes one or more of the following: the number of reference signals and a pattern of the reference signal.

22. The method according to claim 21, characterized in that The configuration of the second reference signal is different from that of the first reference signal, including one or more of the following: the number of the second reference signals is greater than the number of the first reference signals, and the pattern of the second reference signal is different from that of the first reference signal.

23. The method according to any one of claims 18 to 22, characterized in that The channel measurement state of the first terminal is a non-channel acquisition state, and the method further includes: A first precoding matrix is determined through first channel information or second channel information, where the first precoding matrix is a precoding matrix used by the network device to send data to the first terminal through the first device, the first channel information is a left singular vector matrix obtained by SVD decomposition of the autocorrelation matrix of the channel matrix of the second channel, and the second channel information is a left singular vector matrix obtained by SVD decomposition of the autocorrelation matrix of the product of the channel matrix of the third channel and the channel matrix of the second channel, the second channel is a channel between the network device and the first device, and the third channel is a channel between the first device and the first terminal.

24. The method according to claim 23, wherein The channel measurement state of the first terminal is a non-channel acquisition state, and the method further includes: Data is sent to the first terminal through a third precoding matrix; the third precoding matrix is determined based on the first precoding matrix and the second precoding matrix, and the second precoding matrix is the precoding matrix used by the network device to send data to the first terminal.

25. The method according to claim 23 or 24, characterized in that The method further comprises: Data is sent to the second terminal through the fifth precoding matrix; the channel measurement state of the second terminal is a non-channel acquisition state, the fifth precoding matrix is determined based on the first precoding matrix and the fourth precoding matrix, and the fourth precoding matrix is the precoding matrix used by the network device to send data to the second terminal through the first device.

26. A communication system, characterized in that: The device comprises a first device and a second device, wherein the second device is used to transmit data between the first device and a third device, the first device executes the method as claimed in any one of claims 10 to 17, or the first device executes the method as claimed in any one of claims 18 to 25, and the third device executes the method as claimed in any one of claims 1 to 9.

27. A communication device, characterized in that: The invention comprises a processor and a memory; the memory is used to store computer instructions, and when the processor executes the instructions, the computer instructions execute the method according to any one of claims 1 to 9, or the computer instructions execute the method according to any one of claims 10 to 17, or the computer instructions execute the method according to any one of claims 18 to 25.

28. A communication device, characterized in that: The method comprises a unit or module for executing the method according to any one of claims 1 to 9, or a unit or module for executing the method according to any one of claims 10 to 17, or a unit or module for executing the method according to any one of claims 18 to 25.

29. A communication device, characterized in that: include: A communication interface and at least one processor, the communication interface being used to receive and / or send signals, the processor being configured to enable the method of any one of claims 1 to 9 to be executed, or the processor being configured to enable the method of any one of claims 10 to 17 to be executed, or the processor being configured to enable the method of any one of claims 18 to 25 to be executed.

30. A computer-readable storage medium having instructions stored therein, characterized in that: When the instruction is executed on a communication device, the communication device is caused to execute the method according to any one of claims 1 to 9, or the method according to any one of claims 10 to 17, or the method according to any one of claims 18 to 25.

31. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the computer program implements the method according to any one of claims 1 to 9, or the method according to any one of claims 10 to 17, or the method according to any one of claims 18 to 25.

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