Communication method and device

Abstract

The invention provides a communication method and device, which are used for improving the channel estimation efficiency of STAR RIS. According to the method, the RIS may obtain information of a first precoding matrix, information of a second precoding matrix, information of a first time unit, and information of a second time unit. Therefore, the RIS can learn the precoding matrix used by the RIS array used for transmitting the signal in the first time unit and the precoding matrix used by the RIS array used for reflecting the signal in the second time unit so as to transmit the signal in the first time unit and / or reflect the signal in the second time unit. Transmission side channel measurement and reflection side channel measurement can be respectively realized based on the transmission signal and the reflection signal, so that efficient channel estimation of the STAR RIS is realized.

Description

Communication method and device Technical Field

[0001] The present application relates to the field of mobile communication technologies, and in particular to a communication method and device. Background Art

[0002] Reconfigurable intelligent meta-surfaces (RIS)-assisted networking, which utilizes reconfigurable intelligent meta-surfaces (RIS) to control channel characteristics, is considered a key enabling technology for expanding wireless communication network coverage. With advances in metamaterials, research is moving beyond purely reflective or transmissive RIS to include arrays that support simultaneous reflection and transmission to improve channel performance. This type of RIS is known as simultaneously transmitting and reflecting (STAR) RIS.

[0003] Currently, the efficiency of channel estimation for STAR RIS needs to be improved.

[0004] Summary of the Invention

[0005] The present application provides a communication method and apparatus for improving the channel estimation efficiency of STAR RIS.

[0006] In a first aspect, a communication method is provided. This method can be implemented by a reconfigurable smart surface. The reconfigurable smart surface can be a reconfigurable smart surface device or a component of a reconfigurable smart surface device. The RIS can be a STAR RIS, i.e., a RIS that supports both reflection and transmission. The components in this application can include, for example, at least one of a chip, a chip system, a processor, a transceiver, a processing unit, or a transceiver unit. For example, the execution entity is a RIS, and the method can be implemented by the following steps:

[0007] The RIS obtains information about a first precoding matrix, information about a second precoding matrix, information about a first time unit, and information about a second time unit. The RIS includes at least one RIS element, each RIS element is used to transmit and / or reflect signals, the first time unit is a signal transmission time unit, the second time unit is a signal reflection time unit, the first precoding matrix is ​​one or more precoding matrices used by the RIS element for transmitting signals in the first time unit, and the second precoding matrix is ​​one or more precoding matrices used by the RIS element for reflecting signals in the second time unit.

[0008] Based on the first aspect, RIS can obtain the precoding matrix used by the RIS array for transmitting signals in the first time unit and the precoding matrix used by the RIS array for reflecting signals in the second time unit, so as to transmit the signal in the first time unit and / or reflect the signal in the second time unit. Based on the transmitted signal and the reflected signal, the transmitted side channel measurement and the reflected side channel measurement can be respectively realized, thereby realizing efficient channel estimation of STAR RIS.

[0009] In a possible implementation, the RIS may also send a first signal to the first communication device in the first time unit through the RIS array for transmitting signals, and / or send a second signal to the first communication device in the second time unit through the RIS array for reflecting signals.

[0010] In one possible implementation, the RIS may receive at least one of the first precoding matrix information, the second precoding matrix information, the first time unit information, and the second time unit information. For example, the at least one of the first precoding matrix information, the second precoding matrix information, the first time unit information, and the second time unit information may be sent by a network device or a terminal device.

[0011] In one possible implementation, if the RIS is an energy-dispersive STAR RIS, i.e., at least one RIS element in the RIS is used for both transmitting and reflecting signals in the first time unit and for both transmitting and reflecting signals in the second time unit, the RIS may also receive power allocation information indicating the power allocation ratio between the transmitted and reflected signals of the at least one RIS element. Therefore, the energy-dispersive STAR RIS can use the same power allocation information in the first and second time units, avoiding measurement inaccuracies caused by variations in the power allocation ratio, thereby improving channel estimation performance.

[0012] In a possible implementation, the first time unit and the second time unit are both time unit 1, and the RIS can also obtain information about a third precoding matrix, information about a fourth precoding matrix, information about the third time unit, and information about the fourth time unit. The third time unit is a signal transmission time unit, and the fourth time unit is a signal reflection time unit. The third precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the third time unit. The fourth precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the fourth time unit. The third time unit and the fourth time unit are both time unit 2. The time unit 1 and the time unit 2 do not overlap. At least one RIS array is used for transmitting signals and reflecting signals in the time unit 1 and the time unit 2. The first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition. Based on this implementation method, the sum of the transmission side channel and the reflection side channel in time unit 1 can be estimated, and the sum of the transmission side channel and the reflection side channel in time unit 2 can be estimated. Then, the estimation results of the transmission side channel and the estimation results of the reflection side channel in each time unit are analyzed. This can improve the power utilization of RIS and thus improve the reliability of channel estimation.

[0013] In one possible implementation, the RIS may also send a third signal to the first communication device in the third time unit through the RIS array for transmitting signals, and / or send a fourth signal to the first communication device in the fourth time unit through the RIS array for reflecting signals.

[0014] In a possible implementation, the RIS may further receive position information of the RIS array for transmitting signals and / or position information of the RIS array for reflecting signals from the network device.

[0015] In a second aspect, a communication method is provided. The method can be implemented by a first communication device, wherein the first communication device can be a network device, a component in a network device, a terminal device, or a component of a terminal device. The component in this application can include, for example, at least one of a chip, a chip system, a processor, a transceiver, a processing unit, or a transceiver unit. Taking the first communication device as an example, the method can be implemented by the following steps: the first communication device sends information about a first precoding matrix, information about a second precoding matrix, information about a first time unit, and information about a second time unit to a RIS, wherein the RIS includes at least one RIS element, each RIS element being used to transmit and / or reflect signals, the first time unit being a signal transmission time unit, the second time unit being a signal reflection time unit, the first precoding matrix being one or more precoding matrices used by the RIS element for transmitting signals in the first time unit, and the second precoding matrix being one or more precoding matrices used by the RIS element for reflecting signals in the second time unit.

[0016] In a possible implementation manner, the first communication device may further receive a first signal from the RIS during the first time unit, or send a first signal to the RIS during the first time unit.

[0017] In a possible implementation, the first communication device may further receive a second signal from the RIS during the second time unit, or send a second signal to the RIS during the second time unit.

[0018] In one possible implementation, the first communication device may further transmit information about the first time unit to terminal devices in the first set of terminal devices, and / or transmit information about the second time unit to terminal devices in the second set of terminal devices. Therefore, when the first communication device functions as a network device, it may be configured to transmit information about the time unit corresponding to the reference signal to the terminal devices.

[0019] In one possible implementation, the first communication device may also receive information about the first time unit and / or information about the second time unit. Therefore, when the first communication device functions as a network device, it may be configured to send information about the time unit corresponding to the reference signal to the terminal device.

[0020] In one possible implementation, the first communications device may further obtain first channel estimation information of at least one terminal device when the RIS is disabled and second channel estimation information of the at least one terminal device when the RIS array for transmitting signals is enabled. Based on the first and second channel estimation information, the first communications device may determine, from the at least one terminal device, terminal devices in the first terminal device set whose corresponding second channel estimation information is superior to the first channel estimation information. Therefore, the first communications device may accurately determine the first terminal device set based on the first and second channel estimation information.

[0021] In one possible implementation, the first communications device may further obtain first channel estimation information of at least one terminal device when the RIS is disabled and third channel estimation information of the at least one terminal device when the RIS array for signal reflection is enabled. Based on the first and third channel estimation information, the first communications device may determine, from the at least one terminal device, terminal devices in the second set of terminal devices, where the third channel estimation information corresponding to the terminal devices in the second set of terminal devices is superior to the first channel information. Therefore, the first communications device may accurately determine the second set of terminal devices based on the first and third channel estimation information.

[0022] In one possible implementation, at least one of the RIS arrays is used for transmitting signals and reflecting signals in the first time unit, and for transmitting signals and reflecting signals in the second time unit. The first communication device may further send power allocation information to the RIS, where the power allocation information is used to indicate a power allocation ratio between the transmitted signal and the reflected signal of the at least one RIS array.

[0023] In a possible implementation, the first time unit and the second time unit are both time unit 1. The first communication device may further send information of a third precoding matrix, information of a fourth precoding matrix, information of the third time unit, and information of a fourth time unit to the RIS. The third time unit is a signal transmission time unit, and the fourth time unit is a signal reflection time unit. The third precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the third time unit. The fourth precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the fourth time unit. The third time unit and the fourth time unit are both time unit 2. The time unit 1 and the time unit 2 do not overlap. At least one RIS array is used for transmitting signals and reflecting signals in the time unit 1 and the time unit 2. The first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition.

[0024] In a possible implementation manner, the first communication device may be further configured to receive a third signal from the RIS in the third time unit, or send a third signal to the RIS in the third time unit.

[0025] In a possible implementation, the first communication device may be further configured to receive a fourth signal from the RIS during the fourth time unit, or to send a fourth signal to the RIS during the fourth time unit.

[0026] In a possible implementation, the first communication device may be further configured to send position information of a RIS element for transmitting a signal and / or position information of a RIS element for reflecting a signal to the RIS.

[0027] In a possible implementation of the first aspect or the second aspect, any two precoding matrices in the first precoding matrix are orthogonal, and / or any two precoding matrices in the second precoding matrix are orthogonal. Therefore, interference between different precoding matrices can be reduced to improve channel estimation reliability.

[0028] In a possible implementation of the first or second aspect, any two precoding matrices in the first precoding matrix correspond to different sub-time units within the first time unit, and / or any two precoding matrices in the second precoding matrix correspond to different sub-time units within the second time unit. Therefore, different precoding matrices can be used in different sub-time units within the first time unit and / or the second time unit, and scanning of the precoding matrix can be achieved, thereby increasing the probability of using a precoding matrix with better performance for channel estimation and further improving the reliability of channel estimation.

[0029] In a possible implementation of the first or second aspect, the first time unit and the second time unit do not overlap, so that the transmission side channel and the reflection side channel can be measured separately in a time division manner, reducing signal processing complexity.

[0030] In a possible implementation manner of the first aspect or the second aspect, the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy:

[0031] or,

[0032] in, They represent the first precoding matrix, the third precoding matrix, the second precoding matrix, and the fourth precoding matrix respectively.

[0033] Based on this implementation, channel interference when performing joint channel estimation in multiple time units can be improved, thereby further improving channel estimation reliability.

[0034] In a possible implementation of the first or second aspect, at least one RIS element is used to transmit or reflect a signal within the first time unit and to transmit or reflect a signal within the second time unit. The second time unit includes the first time unit, and the length of the second time unit is greater than the length of the first time unit. Based on this implementation, the sum of the transmitted and reflected side channels within the first time unit can be estimated, and the reflected side channel within the second time unit can be estimated. The estimated results of the transmitted and reflected side channels are then analyzed, thereby improving RIS power utilization and channel estimation reliability. Alternatively, the first time unit can include the second time unit, and the length of the first time unit can be greater than the length of the second time unit, achieving the same technical effect.

[0035] In a possible implementation manner of the first aspect or the second aspect, the first time unit and the second time unit belong to the same coherent time.

[0036] In a third aspect, a communication device is provided. The device can implement the method described in any possible design of the first or second aspects. The device has the functions of the RIS or the first communication device described above. The device can be, for example, a terminal device, a functional module in a terminal device, a network device, or a functional module in a network device.

[0037] In an optional implementation, the device may include a module that performs the method / operation / step / action described in the first aspect or the second aspect. The module may be a hardware circuit, software, or a combination of a hardware circuit and software. In an optional implementation, the device includes a processing unit (sometimes also referred to as a processing module) and a communication unit (sometimes also referred to as a transceiver module, a communication module, etc.). The transceiver unit can implement a sending function and a receiving function. When the transceiver unit implements the sending function, it can be called a sending unit (sometimes also referred to as a sending module). When the transceiver unit implements the receiving function, it can be called a receiving unit (sometimes also referred to as a receiving module). The sending unit and the receiving unit can be the same functional module, which is called a transceiver unit, and the functional module can implement a sending function and a receiving function; or, the sending unit and the receiving unit can be different functional modules, and the transceiver unit is a general term for these functional modules.

[0038] Exemplarily, when the apparatus is used to execute the method described in the first aspect or the second aspect, the apparatus may include a communication unit and a processing unit.

[0039] In a fourth aspect, an embodiment of the present application also provides a communication device, comprising a processor for executing a computer program (or computer-executable instructions) stored in a memory. When the computer program (or computer-executable instructions) is executed, the device executes the method in the first aspect or the second aspect and its various possible implementations.

[0040] In a possible implementation, the communication device includes the memory, and the processor and the memory may be integrated together;

[0041] In another possible implementation, the memory is located outside the communication device.

[0042] The communication device also includes a communication interface, which is used for the communication device to communicate with other devices, such as sending or receiving data and / or signals. Exemplarily, the communication interface can be a transceiver, circuit, bus, module or other type of communication interface.

[0043] In a fifth aspect, a computer-readable storage medium is provided, which is used to store computer programs or instructions, which, when executed, enables the method shown in the first aspect or the second aspect and any possible implementation thereof to be implemented.

[0044] In a sixth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the method shown in the first aspect or the second aspect and any possible implementation thereof to be implemented.

[0045] In the seventh aspect, an embodiment of the present application also provides a communication device for executing the methods in the above-mentioned first aspect or second aspect and various possible implementations thereof.

[0046] In an eighth aspect, a chip system is provided, which includes a logic circuit (or it can be understood that the chip system includes a processor, and the processor may include a logic circuit, etc.), and may also include an input and output interface. The input and output interface can be used to input messages or to output messages. The input and output interfaces may be the same interface, that is, the same interface can implement both the sending function (which can be called the output function) and the receiving function (which can be called the input function); or, the input and output interface includes an input interface and an output interface, the input interface is used to implement the receiving function, that is, for receiving messages (which can be called input messages); the output interface is used to implement the sending function, that is, for sending messages (which can be called output messages). The logic circuit can be used to perform operations other than the sending and receiving functions in the method shown in the first aspect or the second aspect and any possible implementation thereof; the logic circuit can also be used to transmit messages to the input and output interface, or receive messages from other communication devices from the input and output interface. The chip system can be used to implement the method shown in the first aspect or the second aspect and any possible implementation thereof. The chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0047] Optionally, the chip system may further include a memory, which may be used to store instructions, and the logic circuit may call the instructions stored in the memory to implement corresponding functions.

[0048] In a ninth aspect, a communication system is provided, which may include a RIS and a first communication device, wherein the RIS can be used to implement the method in the first aspect and any possible implementation thereof, and the first communication device can be used to implement the method in the above-mentioned second aspect and any possible implementation thereof.

[0049] The technical effects brought about by the above second to ninth aspects can be found in the description of the above first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG1 is a schematic diagram of the architecture of a wireless communication system provided in an embodiment of the present application;

[0051] FIG2 is a schematic diagram of the working principle of a RIS provided in an embodiment of the present application;

[0052] FIG3 is a schematic diagram of another working principle of a RIS provided in an embodiment of the present application;

[0053] FIG4 is a schematic diagram of the classification of a STAR RIS provided in an embodiment of the present application;

[0054] FIG5 is a flow chart of a communication method provided in an embodiment of the present application;

[0055] FIG6 is a schematic diagram of the relationship between a time unit and a sub-time unit provided in an embodiment of the present application;

[0056] FIG7 is a schematic diagram of a process for determining terminal device grouping according to an embodiment of the present application;

[0057] FIG8 is a schematic diagram of a scenario and flow of a communication method provided in an embodiment of the present application;

[0058] FIG9 is a schematic diagram of a scenario and flow chart of another communication method provided in an embodiment of the present application;

[0059] FIG10 is a schematic diagram of a scenario and flow chart of another communication method provided in an embodiment of the present application;

[0060] FIG11 is a schematic diagram of a positional relationship between a first time unit and a second time unit provided in an embodiment of the present application;

[0061] FIG12 is a schematic diagram of the positional relationship between a first time unit, a second time unit, a third time unit, and a fourth time unit provided in an embodiment of the present application;

[0062] FIG13 is a schematic diagram of another positional relationship between a first time unit and a second time unit provided in an embodiment of the present application;

[0063] FIG14 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0064] FIG15 is a schematic structural diagram of another communication device provided in an embodiment of the present application;

[0065] FIG16 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] The present application provides a communication method and apparatus. The method and apparatus are based on the same inventive concept. Since the method and apparatus solve similar problems, the implementation of the apparatus and method can refer to each other, and the repetitive parts will not be repeated.

[0067] In the description of this application, words such as "first" and "second" are used solely for descriptive purposes and should not be construed as indicating or implying relative importance or order. It should be noted that this application does not limit the order of appearance of "first," "second," etc. For example, "second" may appear before "first," and this is not a limitation in this application.

[0068] In the description of this application, "at least one (kind)" refers to one (kind) or more (kinds), and more (kinds) refers to two (kinds) or more than two (kinds). "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 represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple. In the description of this application, " / " means "or", for example, a / b means a or b.

[0069] The data transmission method provided in the embodiment of the present application can be applied to a fourth generation (4G) communication system, such as a long term evolution (LTE) communication system, and can also be applied to a fifth generation (5G) communication system, such as a 5G new radio (NR) communication system, or to various future communication systems, such as a sixth generation (6G) communication system. The method provided in the embodiment of the present application can also be applied to a Bluetooth system, a wireless fidelity (Wifi) system, a long range radio (LoRa) system, or a vehicle networking system. The method provided in the embodiment of the present application can also be applied to a satellite communication system, wherein the satellite communication system can be integrated with the above-mentioned communication system.

[0070] To facilitate understanding of the embodiments of the present application, the application scenarios used in the present application are described using the communication system architecture shown in Figure 1 as an example. Referring to Figure 1, a communication system 100 includes a network device 101 and a terminal device 102. The apparatus provided in the embodiments of the present application can be applied to the network device 101 or to the terminal device 102. It will be understood that Figure 1 only illustrates one possible communication system architecture that can be applied in the embodiments of the present application. In other possible scenarios, the communication system architecture may also include other devices.

[0071] The network device 101 is a node in a radio access network (RAN), which may also be referred to as a base station or a RAN node (or device). Currently, some examples of radio access network devices include: a next-generation base station (gNodeB / gNB / NR-NB), a transmission reception point (TRP), an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved NodeB, or home Node B, HNB), a base band unit (BBU), or a wireless fidelity (Wifi) access point (AP), satellite equipment, or network equipment in a 5G communication system, or network equipment in a possible future communication system. The network device 101 may also be another device having network device functions. For example, the network device 101 may also be a device that functions as a network device in device-to-device (D2D) communication, Internet of Vehicles (IoV) communication, or machine communication. The network device 101 may also be a network device in a possible future communication system.

[0072] In some deployments, a gNB may include a centralized unit (CU) and a distributed unit (DU). The gNB may also include a radio unit (RU). The CU implements some gNB functions, while the DU implements some gNB functions. For example, the CU implements radio resource control (RRC) and packet data convergence protocol (PDCP) layer functions, while the DU implements radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. Because RRC layer information ultimately becomes PHY layer information, or is converted from PHY layer information, in this architecture, higher-layer signaling, such as RRC layer signaling or PDCP layer signaling, can also be considered to be sent by the DU, or by both the DU and the RU. It is understood that a network device can be a CU node, a DU node, or a device that includes both a CU node and a DU node. In addition, the CU can be divided into a network device in the access network RAN, and the CU can also be divided into a network device in the core network CN, which is not limited here.

[0073] Terminal device 102, also known as user equipment (UE), mobile station (MS), or mobile terminal (MT), provides voice or data connectivity to users and may also be an IoT device. For example, terminal devices include handheld devices and vehicle-mounted devices with wireless connectivity. At present, terminal devices can be: mobile phones, tablet computers, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smart watches, smart bracelets, pedometers, etc.), vehicle-mounted devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed railways, etc.), virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, smart home devices (such as refrigerators, TVs, air conditioners, electric meters, etc.), intelligent robots, workshop equipment, wireless terminals in unmanned driving, wireless terminals in remote surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, flight equipment (such as intelligent robots, hot air balloons, drones, airplanes), etc. The terminal device can also be other devices with terminal functions. For example, the terminal device can also be a device that serves as a terminal function in D2D communication. In this application, terminal devices with wireless transceiver functions and chips that can be set in the aforementioned terminal devices are collectively referred to as terminal devices.

[0074] To facilitate understanding of the method provided in this application, the following explanations are first made.

[0075] First, the "sending" and "receiving" in the embodiments of the present application indicate the direction of signal transmission. For example, "sending information to XX" can be understood as the destination of the information being XX, which can include direct sending through the air interface, as well as indirect sending through the air interface by other units or modules. "Receiving information from XX" can be understood as the source of the information being XX, which can include direct receiving from XX through the air interface, as well as indirect receiving from XX through the air interface from other units or modules. "Sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface. In other words, sending and receiving can be performed between devices or within a device, for example, between components, modules, chips, software modules, or hardware modules within the device through a bus, trace, or interface. It is understandable that the information may undergo necessary processing, such as encoding, modulation, etc., between the source and destination of the information, but the destination can understand the valid information from the source. Similar expressions in this application can be understood similarly and will not be repeated here.

[0076] Second, the "information of the first precoding matrix", "information of the second precoding matrix", "information of the first time unit" and "information of the second time unit" sent in the embodiment of the present application can be understood as the content information of the "first precoding matrix", "second precoding matrix", "first time unit" and "second time unit" themselves, and can also be understood as indication information, used to indicate the "first precoding matrix", "second precoding matrix", "first time unit" and "second time unit", so that the receiving end knows the content to be indicated.

[0077] The following is an introduction to the technical terms that may be involved in the embodiments of this application.

[0078] (1) Codebook refers to a set of precoding matrices defined by the protocol. There are two ways for network devices to obtain the precoding matrix V:

[0079] Method 1: Network equipment estimates the downlink channel matrix H based on uplink sounding reference signal (SRS) measurements and the reciprocity of the uplink and downlink channels, thereby obtaining V. However, this method is applicable only in time division duplex (TDD) systems. Method 1 is also known as SRS-based precoding.

[0080] Method 2: The terminal device estimates the channel matrix H based on downlink reference signal measurements, and then obtains V, which is then fed back to the network device. Method 2 is also known as precoding matrix indication (PMI)-based precoding.

[0081] For the second method, to reduce implementation complexity and feedback overhead, the current 3rd Generation Partnership Project (3GPP) protocol defines a finite number of quantized precoding matrices, V. This finite set of precoding matrices is called a codebook. The precoding matrices in the codebook are numbered, and the terminal device only needs to feedback the relevant codebook numbers or parameters to indicate the precoding matrix.

[0082] Table 1 shows the codebook for 2 antenna ports.

[0083] Table 1

[0084] From the transmitter's perspective, after layer mapping and antenna port mapping, the network device weights the data of each stream using the precoding matrix (also called weights or codebook weights) in the codebook. The orthogonal frequency division multiplexing (OFDM) signal generator then forms a directional beam at the antenna port, thus achieving layer-to-beam domain conversion. That is, the data stream of each layer is carried on these beams and transmitted in space.

[0085] Taking Table 1 as an example, when the number of transmission layers is 1, the precoding matrix corresponding to index 0 is

[0086] (2) RIS is a digitally reconfigurable artificial electromagnetic surface, an artificial composite structure formed by a large number of subwavelength digitally reconfigurable artificial electromagnetic units arranged in a certain macroscopic manner (periodic or aperiodic). Depending on the specific materials of the reflective or transmissive elements, RIS can be divided into antenna array-based structures and metamaterial-based structures. By adjusting the phase shift of all reflective or transmissive elements, the reflected or transmitted signals can be configured to propagate in their desired direction.

[0087] Furthermore, due to the rapid development of metamaterials, the reflection or transmission coefficient of any element can be configured in real time to adapt to the dynamically fluctuating wireless propagation environment.

[0088] The following description takes the reflective element as an example.

[0089] Because the basic units and arrangements of RIS can be arbitrarily designed, they can overcome the limitations of traditional materials, which are difficult to precisely manipulate at the atomic or molecular level. This allows the construction of extraordinary media parameters unattainable with traditional materials and technologies, such as those with both positive and negative permittivity. Materials with extraordinary media parameters are referred to as metamaterials. Because they control electromagnetic waves by varying the spatial arrangement of digitally encoded units—that is, by altering the state distribution of the basic units, the properties of the electromagnetic field at a specific spatial location can be controlled—in some embodiments, metamaterials can also be referred to as digital electromagnetic metamaterials or electromagnetically coded metamaterials.

[0090] As shown in Figure 3, RIS can be used to create a virtual line of sight (LoS) path between a communication source and a target, preventing interference from obstacles between them. In Figure 3, the source is a user equipment (UE) and the target is a network device. For example, RIS can be installed on large surfaces such as indoor walls or ceilings, or outdoor buildings or signs, to reflect radio frequency (RF) energy away from obstacles.

[0091] For example, see Figure 2, which is a schematic diagram illustrating the operating principle of the RIS module. As shown in Figure 2, the RIS module includes multiple RIS units, each connected via diodes such as PIN diodes and varactor diodes. In this application, a RIS unit may also be referred to as a RIS array. The RIS can reflect received radio waves. It should be understood that when radio waves propagate from one medium to another with a different refractive index, they undergo not only reflection but also refraction. Therefore, the RIS can change the reflection phase difference of the radio waves. It can also be understood that the RIS causes radio waves to follow the generalized Snell's law at reflective or refractive interfaces. In other words, the RIS can cause the reflection angle of a radio wave to differ from the incident angle. Compared to a traditional surface (where the reflection angle of a radio wave is reflection angle 1), the reflection angle of a radio wave can be changed to reflection angle 2. In other words, compared to traditional surfaces, the RIS has the ability to shape radio waves according to the generalized Snell's law.

[0092] Specifically, by controlling the RIS units to adjust the amplitude and / or phase of received signals, the reflection coefficient of any RIS unit can be controlled. Adjusting the amplitude and / or phase of a received signal by a RIS unit can also be considered adjusting the amplitude and / or phase of the RIS unit. It should be understood that if the reflection coefficients of any two RIS units differ, the reflection angles of the radio waves from these two RIS units will also differ. Alternatively, if the transmission coefficients of any two RIS units differ, the refraction angles of the radio waves from these two RIS units will also differ. Therefore, by controlling multiple RIS units to adjust the amplitude and / or phase of received signals, the reflection angle or refraction angle of the radio waves from these RIS units can be adjusted, thereby collaboratively achieving sophisticated three-dimensional (3D) passive beamforming for directional signal enhancement or nulling.

[0093] In some embodiments, the RIS unit can be controlled to adjust the amplitude and / or phase of a received signal by controlling the on / off state of a PIN diode connected to the RIS unit. Controlling the on / off state of the PIN diode refers to controlling the PIN diode to be either on or off, with the on state corresponding to the "on" state and the off state corresponding to the "off" state. For example, by applying different bias voltages to the PIN diode, the PIN diode is turned on or off, thereby also turning the RIS unit connected to the PIN diode on or off. The different states of the multiple RIS units within the RIS result in different amplitude and / or phase adjustments to the received signal, resulting in different reflection coefficients. Therefore, by controlling the states of the RIS units, the amplitude and / or phase adjustments of the received signal by the RIS module can be controlled. For example, the reflection phase of the RIS for radio waves differs by 180°, thereby controlling the reflection coefficient of the RIS, i.e., the phase and / or amplitude of the RIS. This allows the reflection angle of the RIS for radio waves to differ from the incident angle, thus achieving directional beamforming. This can improve wireless network coverage and system capacity, making the RIS widely applicable in communication systems. For example, in embodiments of the present application, RIS can be configured in the source node and / or the cooperating node to implement cooperative communication. Different RIS reflection coefficients result in different reflection angles for radio waves, leading to different beam directions. Therefore, the RIS reflection coefficient can be used to adjust the RIS beam direction. From this perspective, the RIS reflection coefficient can also be referred to as the RIS beamforming parameter (this example will be used below).

[0094] Optionally, the RIS can use an intelligent controller, such as a field programmable gate array (FPGA), to control the on / off state of the PIN diode. In a typical scenario, the workflow can be as follows: the network device calculates the optimal reflection coefficient for the RIS and then sends it to the RIS controller via a dedicated feedback link. The design of the reflection coefficient depends on the channel state information (CSI), which is updated only when the CSI changes, and its duration is much longer than the data symbol duration. For example, each reflective element in the RIS panel is embedded with a PIN photodiode. By controlling the voltage on the bias line, the PIN photodiode can be switched between "on" and "off" modes, thereby achieving a phase shift difference of π radians.

[0095] By adjusting the phase shift of the RIS's reflective elements, the reflected signal can be superimposed with the signal from the direct path (or direct link, i.e., a path not reflected by the RIS) to enhance the desired signal power, or destructively combine to mitigate the harmful effects of multi-user interference. RIS thus provides an additional degree of freedom to further improve system performance, particularly for millimeter-wave (mmWave) communications. Typically, mmWave transmission suffers from high penetration losses, which cannot be easily addressed using large antenna arrays. RIS can also be deployed to create auxiliary transmission links when direct links are blocked.

[0096] It will be appreciated that the amplitude and / or phase of the RIS units can be adjusted based on instructions from the network device. For example, the RIS's adjustments to the signal's amplitude and / or phase can be mapped to multiple precoding matrices in the RIS's codebook. The network device can indicate the index of the precoding matrix in the codebook to the RIS. Based on the network device's instructions, the RIS can determine the precoding matrix with that index and use the amplitude and / or phase corresponding to that precoding matrix to control the reflection coefficients of the RIS units, so that the RIS units achieve signal reflection according to the network device's instructions. Similarly, the network device can indicate the index of the precoding matrix in the codebook to the RIS. Based on the network device's instructions, the RIS can determine the precoding matrix with that index and use the amplitude and / or phase corresponding to that precoding matrix to control the transmission coefficients (or refractive coefficients) of the RIS units, so that the RIS units achieve signal transmission according to the network device's instructions. The codebook can be pre-set or configured by the network device for the RIS. In this application, pre-set can refer to pre-defined, for example, pre-defined through factory configuration or defined by relevant protocols such as 3GPP. The network device configuration may be configured by the network device through messages or information such as RRC messages, MAC control element (CE) or downlink control information (DCI).

[0097] (3) STAR RIS is a RIS that supports both simultaneous reflection and transmission. Generally speaking, RIS is considered a passive reflector. Furthermore, in RIS-MIMO systems, since the number of RIS elements is usually large (possibly up to thousands), directly estimating the RIS channel matrix requires a number of pilots on the same order as the number of RIS elements, resulting in a bottleneck in overhead. With the advancement of metamaterial technology, purely reflective and purely transmissive RIS are no longer able to meet the requirements of use. Therefore, a RIS that supports both simultaneous reflection and transmission, namely STAR RIS, has been proposed.

[0098] Currently, STAR-RS can be divided into three types, as shown in FIG4 , including energy splitting STAR-RIS, mode switching STAR-RIS, and time switching STAR-RIS.

[0099] Each or at least one array on an energy-dispersing STAR-RIS has both transmission and reflection functions (or modes), and the effects of transmission and reflection are determined by the energy distribution across the array. In this application, transmission can also be referred to as refraction. Each array on a mode-switching STAR-RIS has either transmission or reflection functions, but the position of the array used to transmit the signal is uncertain, and / or the position of the array used to reflect the signal is uncertain. Each array on a time-switching STAR-RIS has both transmission and reflection functions, but each array can only have one of these functions at a time, requiring switching based on demand.

[0100] Currently, existing RIS channel estimation methods and processes are mainly aimed at RIS in which all arrays are reflective arrays or transmissive arrays, that is, non-STAR RIS. There is a lack of efficient channel estimation methods for STAR RIS, so the channel estimation efficiency for STAR RIS needs to be improved.

[0101] The present application provides a communication method that can improve the performance of channel estimation for STAR RIS.

[0102] In one possible implementation, the communication method provided herein may be performed by a RIS and a first communication device. The RIS may be configured to receive signals and / or transmit signals to a receiving end via RIS arrays. The RIS arrays may be configured to reflect and / or transmit signals. In other words, the signals transmitted by the RIS to the receiving end may be signals reflected and / or transmitted by the RIS arrays. The signals may originate from the first communication device or the second communication device, where signals may be transmitted between the second communication device and the first communication device via the RIS. Alternatively, the signals may be transmitted to the first communication device or the second communication device. For example, the first communication device may be a network device, and the second communication device may be a terminal device. In another example, the first communication device may be a terminal device, and the second communication device may be a network device. A network device may be, for example, an access network device or a component within an access network device, and a terminal device may be, for example, a terminal device or a component within a terminal device. Components herein may include, for example, at least one of a chip, a chip system, a processor, a transceiver, a processing unit, or a transceiver unit. Furthermore, this application does not preclude the possibility that both the first and second communication devices are terminal devices.

[0103] In this application, a terminal device may be a first terminal device or a second terminal device. The first terminal device belongs to a first terminal device set, and the terminal devices in the first terminal device set may be referred to as transmission-side terminal devices, and the first terminal device set may also be referred to as a transmission-side terminal device set. The second terminal device belongs to a second terminal device set, and the terminal devices in the second terminal device set may be referred to as reflection-side terminal devices, and the second terminal device set may also be referred to as a reflection-side terminal device set.

[0104] It is understood that when the RIS enables the transmission function, the channel between the first terminal device and the network device is enhanced. When the RIS enables the reflection function, the channel between the second terminal device and the network device is enhanced. The following examples will describe how to determine the first and second terminal devices, which will not be elaborated here.

[0105] For example, the RIS may include one or more RIS elements, at least one of which can be used to reflect and / or transmit signals. For example, the RIS can change the transmission coefficient of the RIS element by changing the precoding matrix used by the transmitting-side RIS element, thereby changing the power and / or transmission direction of the transmitted signal. Furthermore, the RIS can change the reflection coefficient of the RIS element by changing the precoding matrix used by the reflecting-side RIS element, thereby changing the power and / or reflection direction of the reflected signal.

[0106] In various embodiments of the communication method, the RIS may be a STAR RIS, for example, an energy-dispersive STAR-RIS, a mode-switching STAR-RIS, or a time-switching STAR-RIS.

[0107] It can be understood that in downlink communication, the network device sends a signal to at least one terminal device via the RIS, and in uplink communication, at least one terminal device may send a signal to the network device via the RIS.

[0108] It is also understood that any signal transmitted between the first communication device and the second communication device, such as the first signal, second signal, third signal, and fourth signal mentioned below, can be used for channel estimation between the first communication device and the second communication device, and / or can be used to determine an optimal precoding matrix for RIS through codebook scanning. The specific uses of these signals will be described below and will not be elaborated here.

[0109] As shown in FIG5 , the communication method provided in the embodiment of the present application may include the following steps:

[0110] S101: A first communication device sends information about a first precoding matrix, information about a second precoding matrix, information about a first time unit, and information about a second time unit to a RIS.

[0111] The RIS may include at least one RIS element, each of which is configured to transmit and / or reflect signals. That is, any RIS element may only reflect or transmit signals at the same time, or any RIS element may both transmit and reflect signals at the same time.

[0112] The following describes the information of the first time unit and the information of the second time unit.

[0113] (1) The information of the first time unit may be used to indicate or determine the time domain position of the first time unit. For example, the information of the first time unit may include the time domain position index of the first time unit. In another example, the information of the first time unit may be periodic information of a RIS array for transmitting a signal to turn on and / or turn off a signal transmission function, where the periodic information includes, for example, the starting time domain position and / or period length of the periodic turning on and / or turning off the signal transmission function.

[0114] It is understood that turning on the transmission function means that the RIS turns on the RIS array for transmitting signals and / or transmits signals through the RIS array for transmitting signals. Turning off the transmission function means that the RIS turns off the RIS array for transmitting signals and / or does not transmit signals through the RIS array for transmitting signals.

[0115] The first time unit is a signal transmission time unit, that is, the RIS element for transmission of the RIS enables the transmission function within the first time unit. The length of the first time unit can be one or more time slots, or one or more OFDM symbols.

[0116] For example, Ta represents the time domain index of the first time unit, which can be expressed as bits indicate Ta.

[0117] (2) The information of the second time unit may be used to indicate or determine the time domain position of the second time unit. For example, the information of the second time unit may include a time domain position index of the second time unit. In another example, the information of the second time unit may include periodic information of turning on and / or off a signal reflection function of a RIS array for reflecting a signal. The periodic information may include, for example, the actual time domain position and / or period length of the periodic turning on and / or off of the signal reflection function.

[0118] It is understood that turning on the reflection function means that the RIS turns on the RIS elements used to reflect signals and / or reflects signals through the RIS elements used to reflect signals. Turning off the reflection function means that the RIS turns off the RIS elements used to reflect signals and / or does not reflect signals through the RIS elements used to reflect signals.

[0119] The second time unit is a signal reflection time unit, that is, the RIS transducer for reflection of the RIS enables the reflection function within the second time unit. The length of the second time unit can be one or more time slots, or one or more OFDM symbols.

[0120] For example, Tb represents the time domain index of the first time unit, which can be used bits indicate Tb.

[0121] The length of the first time unit and / or the length of the second time unit may be predefined or configured by a network device, and is not specifically limited in this application. If configured by a network device, information indicating the length of the first time unit and / or the length of the second time unit may be carried in a message or information such as an RRC message, a MAC CE, or a DCI.

[0122] As a possible implementation, the time unit information can be sent together with the information indicating transmission or reflection. For example, if the information is carried in the same message, the information indicating transmission or reflection can be used to determine whether the time unit information sent together with it is the information of the first time unit or the information of the second time unit. Therefore, it can also be said that the information of the first time unit can include the information of the time unit and the information indicating transmission, and the second time unit can include the information of the second time unit and the information indicating reflection. For example, when the information of the time unit is sent together with the information indicating transmission, the information of the time unit is the information of the first time unit. For another example, when the information of the time unit is sent together with the information indicating reflection, the information of the time unit is the information of the second time unit.

[0123] As an example, information indicating transmission and information indicating reflection may be indicated by 2 bits, for example, 00 indicates turning off RIS, ie, turning off reflection and transmission, 01 indicates reflection, 10 indicates transmission, and 11 indicates reflection + transmission.

[0124] As another possible implementation, the reflective and transmissive functions of the RIS or RIS arrays can be switched between according to a cycle of a set length. This can be understood as the RIS or RIS arrays switching between the transmissive and reflective functions. In this implementation, the information of the first time unit and the information of the second time unit can be information about the time when the RIS array switches between the transmissive and reflective functions, such as the switching period and / or the starting time domain position of the period. Therefore, in this implementation, the first communication device can transmit the switching period and the starting time location information. The switching period and the starting time location information can serve as the information of the first time unit and the information of the second time unit. For example, starting at time t0, one or more RIS arrays of the RIS switch between the transmissive and reflective functions with a switching period of one time slot. In this case, the length of the first time unit and the second time unit are both one time slot. The time domain position of the first time unit and the time domain position of the second time unit can be determined based on the starting time t0 of the periodic switching and the switching period. That is, the information of the first time unit and the second time unit can include the switching period information of one time slot and the position information at time t0.

[0125] It is understood that the RIS arrays used for transmitting signals and the RIS arrays used for reflecting signals can overlap, that is, there can be at least one RIS array used for both transmitting and reflecting signals. Furthermore, this application does not limit the order of the first time unit and the second time unit; the first time unit can precede the second time unit, or the second time unit can precede the first time unit.

[0126] Optionally, the order of the first time unit and the second time unit can be determined based on the grouping of the terminal devices with the best channel quality. For example, if the terminal device with the best channel quality is the first terminal device, the first time unit can precede the second time unit, so that the channel of the terminal device with better channel quality can be measured first. For another example, if the terminal device with the best channel quality is the second terminal device, the second time unit can precede the first time unit, so that the channel of the terminal device with better channel quality can be measured first.

[0127] The information of the first precoding matrix and the information of the second precoding matrix are introduced below.

[0128] (1) The information of the first precoding matrix may be an index of the first precoding matrix. For example, the index may be used to indicate the first precoding matrix from a codebook in which the precoding matrix is ​​located.

[0129] The first precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the first time unit. If the first precoding matrix includes multiple precoding matrices, the RIS array for transmitting signals can use different precoding matrices in multiple sub-time units within the first time unit.

[0130] Optionally, the multiple precoding matrices included in the first precoding matrix are orthogonal to each other.

[0131] As shown in FIG6 , the first time unit is, for example, a time slot. The first time unit may include multiple OFDM symbols, and one or more OFDM symbols may serve as a sub-time unit.

[0132] Exemplarily, the first precoding matrix can be expressed as W R , Where C represents a complex matrix, N×T1 represents the dimension of the complex matrix, N is the number of RIS elements in the RIS used for the transmission signal, and T1 is the number of sub-time units contained in the first time unit. Different sub-time units correspond to different precoding matrices. In this example, the information of the first precoding matrix may include (1+X1) bits. Among them, one bit is used to indicate transmission, for example, 0 indicates transmission and 1 indicates reflection; X1 bits can indicate the transmission-side precoding matrix or its index in the codebook (or quantized precoding matrix), for example, X1 bits are the binary value of the index of the first precoding matrix.

[0133] (2) The information of the second precoding matrix may be an index of the second precoding matrix.

[0134] The second precoding matrix is ​​one or more precoding matrices used by the RIS element for reflecting the signal in the second time unit. If the second precoding matrix includes multiple precoding matrices, the RIS element for reflecting the signal may use different precoding matrices in multiple sub-time units within the second time unit.

[0135] Optionally, the multiple precoding matrices included in the second precoding matrix are orthogonal to each other.

[0136] Still taking FIG. 6 as an example, the second time unit is, for example, a time slot, the first time unit may include multiple OFDM symbols, and one or more OFDM symbols may serve as a sub-time unit.

[0137] Exemplarily, the second precoding matrix can be expressed as W T , Where N is the number of RIS elements in the RIS used for reflected signals, and T2 is the number of sub-time units contained in the second time unit. Different sub-time units correspond to different precoding matrices. In this example, the information about the second precoding matrix may include (1 + X2) bits. One bit indicates transmission, for example, 0 for transmission and 1 for reflection. The X2 bits may indicate the reflection-side precoding matrix or its index in the codebook, for example, the X2 bits are the binary value of the index of the second precoding matrix.

[0138] In one possible embodiment, the RIS for the transmitted signal and the RIS for the reflected signal may be configured with different codebooks, referred to as the transmitted-side codebook and the reflected-side codebook, respectively. The first precoding matrix may be one or more precoding matrices in the transmitted-side codebook, and the second precoding matrix may be one or more precoding matrices in the reflected-side codebook.

[0139] Taking determining the first precoding matrix as an example, the first precoding matrix can be determined based on the prior channel estimation result corresponding to the transmitted signal. For example, RIS uses multiple precoding matrices in the transmission side codebook to transmit the signal between the first communication device and the second communication device in a scanning manner, so that the first communication device and / or the second communication device performs channel estimation based on the received signal, and determines one or more precoding matrices with the best channel quality as the first precoding matrix.

[0140] In another possible embodiment, the first precoding matrix may be a fixed orthogonal matrix. For example, the first precoding matrix may be the product of a discrete Fourier transform (DFT) matrix or a Hadamard matrix and the elements at corresponding positions in a spatial orthogonal matrix. The spatial orthogonal matrix may be a matrix that satisfies spatial orthogonality conditions. The following text will describe how to determine this precoding matrix in conjunction with the spatial orthogonality relationship, which will not be expanded upon here.

[0141] The inner product of any two columns or rows in a spatial orthogonal matrix is ​​0.

[0142] In addition, it is not excluded that one or more precoding matrices are determined as the first precoding matrix from the transmission side codebook by random selection or in descending order of index or in descending order of index.

[0143] The method for determining the second precoding matrix may refer to the method for determining the first precoding matrix, and will not be described in detail.

[0144] As a possible implementation method, if the first communication device is a network device, the information of the first precoding matrix and / or the information of the second precoding matrix can be carried in an RRC message, a MAC CE or a DCI. In addition, the information of the first precoding matrix and / or the information of the second precoding matrix, or the RRC message, MAC CE or DCI carrying the information of the first precoding matrix and / or the information of the second precoding matrix can be carried in a PDCCH or a PDSCH. If the first communication device is a terminal device, the information of the first precoding matrix and / or the information of the second precoding matrix can be carried in uplink control information (UCI). Optionally, the UCI can be carried in a PUCCH or a PUSCH.

[0145] As a possible implementation method, if the first communication device is a network device, the information of the first time unit and / or the information of the second time unit can be carried in an RRC message, MAC CE or DCI. In addition, the information of the first precoding matrix and / or the information of the second precoding matrix, or the RRC message, MAC CE or DCI carrying the information of the first precoding matrix and / or the information of the second precoding matrix can be carried in PDCCH or PDSCH. If the first communication device is a terminal device, the information of the first time unit and / or the information of the second time unit can be carried in UCI. Optionally, UCI can be carried in PUCCH or PUSCH.

[0146] Optionally, the first communication device may further indicate the position of the RIS array for transmitting the signal and / or the position of the RIS array for reflecting the signal in the RIS. For example, the first communication device may send the row index and / or column index of the RIS array in the RIS template to the RIS.

[0147] S102: The RIS obtains information about the first precoding matrix, information about the second precoding matrix, information about the first time unit, and information about the second time unit.

[0148] Based on S102, the RIS can obtain the precoding matrix used by the RIS array for transmitting the signal in the first time unit and the precoding matrix used by the RIS array for reflecting the signal in the second time unit, so as to transmit the signal in the first time unit and / or reflect the signal in the second time unit. Based on the transmitted signal and the reflected signal, the transmission side channel measurement and the reflection side channel measurement can be respectively performed to achieve efficient channel estimation of the STAR RIS, thereby improving the channel estimation efficiency of the STAR RIS.

[0149] Therefore, the RIS may transmit the signal through the RIS elements used for transmitting the signal within the first time unit based on the information of the first time unit, wherein the elements use the first precoding matrix within the first time unit. And / or, the RIS may reflect the signal through the RIS elements used for reflecting the signal within the second time unit based on the information of the second time unit, wherein the elements use the first precoding matrix within the second time unit.

[0150] It can be understood that although the RIS is configured with information about the first precoding matrix, information about the second precoding matrix, information about the first time unit, and information about the second time unit, the RIS does not necessarily transmit the signal through the RIS array for transmitting the signal within the first time unit, and does not necessarily reflect the signal through the RIS array for reflecting the signal within the second time unit.

[0151] As a possible implementation, the first communication device may be a network device, and correspondingly, the second communication device may be a terminal device. As described in this application, the terminal device may belong to a first terminal device set or a second terminal device set. If the terminal device belongs to the first terminal device set, i.e., the terminal device belongs to a transmission-side terminal device, then the channel between the network device and the transmission-side terminal device or the selection of the RIS precoding matrix can be implemented based on the forwarding of signals by the RIS. If the terminal device belongs to the second terminal device set, i.e., the terminal device belongs to a reflection-side terminal device, then the channel between the network device and the reflection-side terminal device or the selection of the RIS precoding matrix can be implemented based on the forwarding of signals by the RIS.

[0152] This application also provides another communication method that can be used to accurately determine the first terminal device set and the second terminal device set, improve the efficiency of terminal device grouping, and ensure accurate grouping. This method is described below with reference to FIG7 . It is understood that the processes of FIG5 and FIG7 can be implemented in combination. For example, the process shown in FIG7 can be executed before the process shown in FIG5 . Furthermore, the processes of FIG5 and FIG7 can also be implemented separately. For example, the process shown in FIG7 can be implemented independently of the process shown in FIG5 .

[0153] As shown in FIG7 , the communication method provided in the embodiment of the present application may include S201 to S203, or S201, S204 to S205, or the steps shown in S201 to S205:

[0154] S201: A first communication device obtains first channel estimation information of at least one terminal device when RIS is turned off.

[0155] In the present application, the channel estimation information may include at least one of the following: channel quality indication (CQI), reference signal receiving power (RSRP) or signal to interference plus noise ratio (SINR) or other parameters or indicators used to characterize the channel estimation results.

[0156] The first channel estimation information is channel estimation information of at least one terminal device collected when RIS is turned off.

[0157] As shown in Figure 8, taking the first communication device as a network device as an example, the network device can instruct the RIS to disable the reflection function and the transmission function, or in other words, to disable the RIS. During the time unit in which the RIS is disabled, one or more terminal devices (e.g., all terminal devices) within one or more cells (e.g., all cells) of the network device send reference signals to the network device, and the network device measures the reference signals sent by each terminal device to obtain first channel estimation information. In the above process, the network device can indicate the time to disable the RIS (e.g., indicating the index of the time unit), and / or the network device can send reference signal configuration information to one or more terminal devices within the cell, so that the terminal devices send reference signals to the network device during the RIS shutdown time.

[0158] Optionally, the reference signal may be any type of uplink reference signal, such as SRS, etc. The configuration information of the reference signal is used to configure parameters such as the type, time-frequency resources, or power of the reference signal.

[0159] As an example, the first communication device may use two bits to indicate that the RIS is off, that the transmission function is on and the reflection function is off, that the reflection function is on and the transmission function is off, or that the transmission and reflection functions are on. For example, the two bits may be 00, 01, 10, and 11, where 00 indicates that the RIS is off, i.e., both reflection and transmission are off; 01 indicates that both reflection and transmission are on; 10 indicates that both transmission and reflection are on; and 11 indicates that both reflection and transmission are on.

[0160] S202: The first communication device obtains second channel estimation information of at least one terminal device when the RIS turns on the RIS element for transmitting the signal.

[0161] The second channel estimation information may be channel estimation information of the terminal device when only the RIS arrays used for transmitting signals among all RIS arrays are enabled, or channel estimation information of the terminal device when only the transmission function is enabled and the reflection function is not enabled. The type of the first channel estimation information and the type of the second channel estimation information are the same, for example, both are RSRP or both are SINR.

[0162] As shown in Figure 9, the network device can instruct the RIS to enable the transmission function and disable the reflection function. During the time period when the RIS enables the transmission function, one or more terminal devices (e.g., all terminal devices) within one or more cells (e.g., all cells) of the network device transmit reference signals to the network device. The reference signals are transmitted by the RIS and reach the network device. The network device measures the reference signals transmitted by each terminal device to obtain second channel estimation information. During the above process, the network device can indicate the time to enable the transmission function to the RIS and / or send reference signal configuration information to one or more terminal devices within the cell, so that the terminal devices transmit reference signals to the network device during the time period when the RIS enables the transmission function.

[0163] Optionally, the reference signal may be any type of uplink reference signal, such as SRS, etc. The configuration information of the reference signal is used to configure parameters such as the type, time-frequency resources, or power of the reference signal.

[0164] It will be appreciated that the reference signal transmitted by the terminal device during the time unit in which the RIS is disabled is identical to the reference signal transmitted by the terminal device during the time unit in which the RIS transmission function is enabled, so that the network device can identify the degree of change between the first channel estimation information and the second channel estimation information and then determine the terminal device grouping based on the degree of change, as specifically shown in S202. For example, the reference signal transmitted by the same terminal device during the time unit in which the RIS is disabled and the time unit in which the RIS transmission function is enabled may have the same signal type, transmit power, frequency domain location, and transmit antenna port.

[0165] S203: The first communication device determines a terminal device in the first terminal device set from at least one terminal device based on the first channel estimation information and the second channel estimation information, wherein the second channel estimation information corresponding to the terminal device in the first terminal device set is better than the first channel estimation information.

[0166] Specifically, the first communication device can determine whether any terminal device belongs to the first terminal device set based on the first channel estimation information and the second channel estimation information of any terminal device. Therefore, by traversing all terminal devices and determining whether all terminal devices belong to the first terminal device set, all terminal devices in the first terminal device set can be determined.

[0167] Still taking the example of the first communication device being a network device, if the network device determines that the second channel estimation information of a certain terminal device does not change much compared to the first channel estimation information of the same terminal device, or that the channel estimation result is not significantly enhanced, it means that enabling the transmission function of RIS has not enhanced the channel between the terminal device and the network device. Therefore, the network device can determine that the terminal device does not belong to the transmission-side terminal device, that is, determines that the terminal device does not belong to the first terminal device set.

[0168] It can be understood that based on S201 to S203, the terminal devices whose channels are enhanced when the transmission function of the RIS is turned on can be efficiently and accurately determined. Determining the channels when the transmission function of the RIS is turned on based on these terminal devices can improve the measurement accuracy of the transmission side channel of the RIS.

[0169] S204: The first terminal device obtains third channel estimation information of at least one terminal device when the RIS array for reflecting signals is turned on.

[0170] The third channel estimation information may be channel estimation information of the terminal device when only the RIS array used for signal reflection among all RIS arrays is enabled, or channel estimation information of the terminal device when only the reflection function is enabled and the transmission function is not enabled. The type of the first channel estimation information and the third channel estimation information is the same, for example, both are RSRP or both are SINR.

[0171] As shown in Figure 10, the network device can instruct the RIS to enable the reflection function and disable the transmission function. During the time period when the RIS enables the reflection function, one or more terminal devices (e.g., all terminal devices) within one or more cells (e.g., all cells) of the network device transmit reference signals to the network device. The reference signals pass through the RIS and reach the network device. The network device measures the reference signals transmitted by each terminal device to obtain third channel estimation information. During the above process, the network device can instruct the RIS to enable the reflection function, and / or the network device can transmit reference signal configuration information to one or more terminal devices within the cell, so that the terminal devices transmit reference signals to the network device during the time period when the RIS enables the reflection function.

[0172] Optionally, the reference signal may be any type of uplink reference signal, such as SRS, etc. The configuration information of the reference signal is used to configure parameters such as the type, time-frequency resources, or power of the reference signal.

[0173] It will be appreciated that the reference signal transmitted by the terminal device during the RIS-off time unit is identical to the reference signal transmitted by the terminal device during the RIS-reflection function-on time unit, allowing the network device to identify the degree of change between the first channel estimation information and the third channel estimation information and then determine the terminal device grouping based on the degree of change, as specifically shown in S204. For example, the reference signal transmitted by the same terminal device during the RIS-off time unit and the RIS-reflection function-on time unit may have the same signal type, transmit power, frequency domain location, and transmit antenna port.

[0174] It can also be understood that the present application does not limit the execution sequence between the above S201, S202 and S204, that is, the time unit for turning off the RIS, the time unit for turning on the transmission function of the RIS and turning off the reflection function of the RIS, and the time unit for turning on the reflection function of the RIS and turning off the transmission function of the RIS, that is, the execution order between any two or three is not limited.

[0175] S205: The first communication device determines a terminal device in the second terminal device set from at least one terminal device based on the first channel estimation information and the third channel estimation information, where the third channel estimation information corresponding to the terminal device in the second terminal device set is better than the first channel estimation information.

[0176] Specifically, the first communication device can determine whether any terminal device belongs to the second terminal device set based on the first channel estimation information and the third channel estimation information of the terminal device. Therefore, by traversing all terminal devices and determining whether all terminal devices belong to the second terminal device set, all terminal devices in the second terminal device set can be determined.

[0177] Still taking the example of the first communication device being a network device, if the network device determines that the third channel estimation information of a certain terminal device has not changed much compared to the first channel estimation information of the same terminal device, or the channel estimation result has not been significantly enhanced, it means that turning on the reflection function of RIS has not enhanced the channel between the terminal device and the network device. Therefore, the network device can determine that the terminal device does not belong to the reflection side terminal device, that is, determines that the terminal device does not belong to the second terminal device set.

[0178] It can be understood that based on S201, S204 to S205, the terminal devices whose channels are enhanced when the reflection function of the RIS is enabled can be efficiently and accurately determined. By determining the channel when the reflection function of the RIS is enabled based on these terminal devices, the reflection side channel measurement accuracy of the RIS can be improved.

[0179] It can be understood that the actions performed by the first communication device in FIG. 7 may also be implemented by other communication devices, for example, by replacing the execution subject in FIG. 7 with a RIS or other network element.

[0180] Figures 8 to 10 above illustrate the method for determining the set of first terminal devices, using the example of a first communication device being a network device. It will be appreciated that when the first communication device is a terminal device with a terminal device grouping function, as described with reference to Figures 8 to 10 , one or more terminal devices within the cell of the network device transmit reference signals to the network device when the RIS (Reflection Function) is disabled and the RIS (Transmittance Function) is enabled, respectively. The network device then transmits first channel estimation information and second channel estimation information for each of the plurality of terminal devices to the terminal devices with the terminal device grouping function, thereby implementing S201 and / or S202. The terminal devices with the terminal device grouping function then execute the terminal device grouping method shown in S203. Alternatively, one or more terminal devices within the cell of the network device may transmit reference signals to the network device when the RIS (Reflection Function) is disabled and the RIS (Reflection Function) is enabled, respectively. The network device then transmits first channel estimation information and third channel estimation information for each of the plurality of terminal devices to the terminal devices with the terminal device grouping function, thereby implementing S201 and / or S204. The terminal devices with the terminal device grouping function then execute the terminal device grouping method shown in S205.

[0181] The terminal device with the terminal device grouping function may be one or more terminal devices within a cell of the network device. For example, the network device may designate one terminal device from the one or more terminal devices as a terminal device with the terminal device grouping function.

[0182] It is understood that the present application does not limit the execution order between any two or more processes in Figures 8 to 10. For example, the processes may be executed in descending order or in ascending order, or in a random order. In actual applications, the execution order between any two or more processes in Figures 8 to 10 may be determined by the first communication device or the network device.

[0183] It can also be understood that the processes shown in Figures 8 to 10 are an illustration of a method for determining a first terminal device and / or a second terminal device, in which the network device acts as a first communication device to determine channel estimation information based on a reference signal sent by the terminal device, and determines the set to which the terminal device belongs based on the channel estimation information.

[0184] Similarly, the network device may also transmit reference signals when the RIS is disabled, when the RIS's reflection function is enabled and the RIS's transmission function is disabled, and when the RIS's transmission function is enabled and the RIS's reflection function is disabled. One or more terminal devices in one or more cells of the network device may perform measurements based on the received reference signals to obtain the first channel estimation information in S201, the second channel estimation information in S202, and the third channel estimation information in S204. In this embodiment, the terminal device may perform measurements based on reference signals received during time periods when the RIS is disabled to obtain the first channel estimation information; the terminal device may also perform measurements based on reference signals received during time periods when the RIS's transmission function is enabled and the RIS's reflection function is disabled to obtain the second channel estimation information; and the terminal device may also perform measurements based on reference signals received during time periods when the RIS's reflection function is enabled and the RIS's transmission function is disabled to obtain the third channel estimation information. The manner in which the network device instructs the RIS to disable the RIS, enable the RIS's reflection function and disable the RIS's transmission function, and enable the RIS's transmission function and disable the RIS's reflection function is described with reference to FIG. 7 and will not be repeated here.

[0185] In addition, in this embodiment, the terminal device may further transmit at least one of the first channel estimation information, the second channel estimation information, and the third channel estimation information to the network device, so that the network device determines the group to which each terminal device belongs based on the received channel estimation information. For example, in S202, the terminal device may transmit the first channel estimation information and the second channel estimation information, so that the network device may determine whether the terminal device belongs to the first terminal device set based on the first channel estimation information and the second channel estimation information of the same terminal device; in S205, the terminal device may transmit the first channel estimation information and the third channel estimation information, so that the network device may determine whether the terminal device belongs to the second terminal device set based on the first channel estimation information and the third channel estimation information of the same terminal device.

[0186] Optionally, the reference signal sent by the network device in this embodiment may be a channel state information reference signal (CSI reference signal, CSI-RS). In addition, the first channel estimation information, the second channel estimation information, and the third channel estimation information in this embodiment may be CSI, for example, including indicators such as CQI, SINR, or RSRP.

[0187] Optionally, in this embodiment, the terminal device may determine the first channel estimation information and send the first channel estimation information to the network device within the time unit in which the RIS is turned off, or may send the first channel estimation information after the time unit in which the RIS is turned off. In addition, the terminal device may determine the second channel estimation information and send the second channel estimation information to the network device within the time unit in which the transmission function of the RIS is turned on and the reflection function of the RIS is turned off, or may send the second channel estimation information after the time unit. The terminal device may determine the second channel estimation information and send the second channel estimation information to the network device within the time unit in which the reflection function of the RIS is turned on and the transmission function of the RIS is turned off, or may send the second channel estimation information after the time unit. In addition, the terminal device may also send at least two of the first channel estimation information, the second channel estimation information, and the third channel estimation information within the same time unit based on the scheduling information of the network device. For example, at least two of the first channel estimation information, the second channel estimation information, and the third channel estimation information may be present in the same information and / or signaling.

[0188] As a possible implementation of this embodiment, the network device uses the same signal type, transmission power, frequency domain position of the reference signal, and transmitting antenna port to send the reference signal within the time unit in which the RIS is turned off, the time unit in which the transmission function of the RIS is turned on and the reflection function of the RIS is turned off, and the time unit in which the reflection function of the RIS is turned on and the transmission function of the RIS is turned off.

[0189] In another possible implementation, the first terminal device and / or the second terminal device may be determined based on the locations of the network device, the RIS, and the terminal device. For example, if the terminal device and the network device are both located on the same side of the RIS front, or the terminal device is located on the reflection side of the RIS, and signals can be transmitted between the terminal device and the network device via reflection from the RIS, then the terminal device is a reflection-side terminal device. Alternatively, if the terminal device and the network device are both located on different sides of the RIS front, or the terminal device is located on the transmission side of the RIS, and signals can be transmitted between the terminal device and the network device via transmission from the RIS, then the terminal device is a transmission-side terminal device.

[0190] In addition, the first terminal device set and / or the second terminal device set may be determined using integrated sensing and communication (ISAC) technology. The first terminal device set and / or the second terminal device set may be determined by a network device and / or a core network element based on the ISAC technology. Furthermore, in embodiments where the network device does not serve as the first communication device, the network device may send identifiers of terminal devices in the first terminal device set and / or identifiers of terminal devices in the second terminal device set to the first communication device. In embodiments where the first terminal device set and / or the second terminal device set are determined by a core network element based on the ISAC technology, the core network element may also send identifiers of terminal devices in the first terminal device set and / or identifiers of terminal devices in the second terminal device set to the first communication device. For example, where the first communication device is a network device, the identifiers of terminal devices in the first terminal device set and / or identifiers of terminal devices in the second terminal device set may be carried in a terminal device identifier table sent by the core network element to the network device.

[0191] In one possible embodiment, in ISAC technology, a network device and / or core network element can determine the location of a terminal device based on relevant processes and methods related to perception and / or positioning. The network device, RIS, and terminal device can then be used to infer whether the terminal device is located on the transmission side or the reflection side of the RIS by calculating the geometric positional relationship among the three. If a terminal device is on the transmission side of the RIS, it can be considered a terminal device in a first set of terminal devices; if it is on the reflection side of the RIS, it can be considered a terminal device in a second set of terminal devices. For example, if the terminal device and the network device are both located on the same side of the RIS front, i.e., the terminal device is on the reflection side of the RIS, then the terminal device is a reflection-side terminal device. Alternatively, if the terminal device and the network device are both located on different sides of the RIS front, i.e., the terminal device is on the transmission side of the RIS, then the terminal device is a transmission-side terminal device.

[0192] The following describes an embodiment of the communication method shown in FIG5 when the first time unit and the second time unit do not overlap, and an embodiment of the communication method shown in FIG5 when the first time unit and the second time unit overlap.

[0193] In Example 1, the first time unit and the second time unit can be located at different time domain locations, that is, the first time unit and the second time unit do not overlap. In this application, non-overlapping time units means that multiple time units do not contain the same time domain location. The RIS in Example 1 is, for example, an energy-dispersive STAR RIS, a mode-switching STAR RIS, or a time-switching STAR RIS.

[0194] As shown in Figure 11, the first time unit and the second time unit are time slot 1 and time slot 2, respectively, and time slot 1 and time slot 2 are different. Therefore, the RIS can use the first precoding matrix as the precoding matrix for the RIS array for transmitting signals in time slot 1, and / or use the second precoding matrix as the precoding matrix for the RIS array for reflecting signals in time slot 2. In addition, time slot 1 and time slot 2 can be two consecutive time slots or two discontinuous time slots, which is not required by this application.

[0195] Furthermore, in Example 1, the first terminal device may transmit a first reference signal in time slot 1, and the second terminal device may transmit a second reference signal in time slot 2. Therefore, the network device can receive the first reference signal transmitted by the first terminal device via the RIS in time slot 1 to perform channel estimation for the first terminal device on the transmission side. Furthermore, the network device can receive the second reference signal transmitted by the second terminal device via the RIS in time slot 2 to perform channel estimation for the second terminal device on the reflection layer.

[0196] In embodiment 1, the first communication device may also send information about the first precoding matrix, information about the second precoding matrix, information about the first time unit, and information about the second time unit to the RIS. The first communication device may be a first terminal device, a second terminal device, or a network device.

[0197] Furthermore, if the RIS is an energy-dispersive STAR RIS, the first communication device may also transmit power allocation information for each RIS element to the RIS. This power allocation information may be used to indicate the power allocation ratios for the transmitted and reflected signals of the RIS elements used for transmitting and reflecting signals. Optionally, any RIS element used for transmitting and reflecting signals may use the same power allocation information in both the first and second time units.

[0198] If the RIS element is a mode-switched STAR RIS, the first communication device may further send position information of the RIS element for transmitting the signal and / or position information of the RIS element for reflecting the signal to the RIS.

[0199] Based on Example 1, the transmission side reference signal and the reflection side reference signal can be sent respectively in different time units in a time division manner, so that the transmission side channel and the reflection side channel can be estimated respectively, which can reduce the complexity of signal processing.

[0200] In Example 2, the first time unit and the second time unit can be located at the same time domain location, that is, the first time unit and the second time unit completely overlap, or the first time unit and the second time unit are the same time unit, hereinafter referred to as time unit 1. Therefore, the RIS can simultaneously transmit the first reference signal and reflect the second reference signal within time unit 1. In this application, time unit 1 can be one or more time slots, or one or more OFDM symbols.

[0201] The first terminal device may transmit a first reference signal in time unit 1, and the second terminal device may transmit a second reference signal in time unit 1. Therefore, the network device may estimate the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device in time unit 1. For example, the network device may estimate the reference signals received in time unit 1, and the estimation result may be the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device.

[0202] Furthermore, in embodiment 2, the first terminal device may further transmit a third reference signal in a third time unit, and the second terminal device may further transmit a fourth reference signal in a fourth time unit. The RIS may further transmit the third reference signal in the third time unit through the RIS transducer for signal transmission, and reflect the fourth reference signal in the fourth time unit through the RIS transducer for signal reflection. In the third time unit, the precoding matrix used by the RIS transducer for signal transmission is the third precoding matrix, and in the fourth time unit, the precoding matrix used by the RIS transducer for signal reflection is the fourth precoding matrix. The third precoding matrix may include one or more precoding matrices, and the fourth precoding matrix may include one or more precoding matrices. The third precoding matrix may refer to the description of the first precoding matrix, except that the corresponding time units are different: the first time unit and the third time unit, respectively. The fourth precoding matrix may refer to the description of the second precoding matrix, except that the corresponding time units are different: the second time unit and the fourth time unit, respectively. Furthermore, the third precoding matrix may be the same as or different from the first precoding matrix, and the second precoding matrix may be the same as or different from the fourth precoding matrix.

[0203] The RIS in Example 2 is, for example, an energy-dispersive STAR RIS.

[0204] As a possible implementation, as shown in Figure 12, the third time unit and the fourth time unit are the same time unit, hereinafter referred to as time unit 2. Time unit 2 can be one or more time slots, or one or more OFDM symbols. Among them, time unit 1 and time unit 2 can be two consecutive time units, or they can be discontinuous. In addition, in the time domain, time unit 1 can be located before time unit 2, or time unit 2 can be located before time unit 1. In this implementation, the network device can obtain the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device based on the reference signal received in time unit 2, and determine the channel estimation result corresponding to the first terminal device and the channel estimation result corresponding to the second terminal device in combination with the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device obtained by estimating the received signal in time unit 1.

[0205] In this implementation, the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy the spatial orthogonality condition. As described above, the inner product of any two columns or rows in a matrix that satisfies the spatial orthogonality condition is 0.

[0206] The network device can specifically determine the channel estimation result corresponding to the first terminal device and the channel estimation result corresponding to the second terminal device based on the spatial orthogonality condition, the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device estimated in time unit 1, and the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device estimated in time unit 2.

[0207] Exemplarily, the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy:

[0208] or,

[0209] in, represent the first precoding matrix, the third precoding matrix, the second precoding matrix and the fourth precoding matrix respectively.

[0210] In one possible embodiment, the above spatial orthogonal relationship can be indicated by a precoding matrix, which can be called a spatial orthogonal matrix, or a fifth precoding matrix. As described above, the inner product of any two columns or rows in the spatial orthogonal matrix is ​​0. For example, for N_UE terminal devices, the spatial orthogonal matrix can be expressed as W air , W air ∈C N_UE×N_UEY bits may be used to indicate the spatial orthogonal matrix. For example, Y bits are used to indicate the index of the spatial orthogonal matrix in a preset codebook.

[0211] or,

[0212] For example, when Y bits indicate a spatial orthogonal matrix as shown in formula (1), it means that the first precoding matrix, the third precoding matrix, the second precoding matrix and the fourth precoding matrix satisfy the spatial orthogonal relationship shown in formula (1).

[0213] The following describes the method for determining the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix in the present application in conjunction with the spatial orthogonal matrix.

[0214] Assume that the first precoding matrix is The second precoding matrix, the third precoding matrix and the fourth precoding matrix may be based on And the spatial orthogonal matrix W air middle The product of the corresponding element values ​​is determined, where It can be a DFT matrix or a Hadamard matrix.

[0215] With the above W air Taking the relevant formula (1) as an example, The corresponding element is The value corresponding to this element is 1, that is, Similarly, the third precoding matrix

[0216] As a possible embodiment, time unit 1 and time unit 2 may each include multiple sub-time units. Each time unit may correspond to a precoding matrix. For example, as shown in FIG12 , different sub-time units (e.g., different OFDM symbols) in time slot 1 correspond to different precoding matrices in the first precoding matrix, and different sub-time units (e.g., different OFDM symbols) in time slot 2 correspond to different precoding matrices in the second precoding matrix. Therefore, in time slot 1, the RIS may use different precoding matrices in different sub-time units to transmit the reference signal, and in time slot 2, the RIS may use different precoding matrices in different sub-time units to reflect the reference signal. This allows scanning of the precoding matrix, increases the probability of using a precoding matrix with better performance to send the reference signal, and improves channel estimation reliability.

[0217] For example, assume that the first terminal device set and the second terminal device set include the same number of terminal devices, the terminal devices in the first terminal device set are labeled UE 1 to UE K / 2, and the terminal devices in the second terminal device set are labeled UE K / 2 to UE K. Each sub-time unit may correspond to the same UE. For example, for time slot 1, UE 1 to UE K / 2 transmit reference signals in each sub-time unit, and the precoding matrix used for the RIS transmitted reference signal may be different in each sub-time unit. For another example, for time slot 2, UE K / 2 to UE K transmit reference signals in each sub-time unit, and the precoding matrix used for the RIS reflected reference signal may be different in each sub-time unit.

[0218] In embodiment 2, both time unit 1 and time unit 2 can be used for RIS reflection and transmission of reference signals, thereby improving the power utilization of RIS and reducing power loss, thereby improving the channel estimation accuracy.

[0219] In embodiment 3, the second time unit includes the first time unit, and the length of the second time unit is greater than the length of the first time unit; or, the first time unit includes the second time unit, and the length of the first time unit is greater than the length of the second time unit, that is, the first time unit and the second time unit partially overlap.

[0220] Embodiment 3 is described below with reference to Fig. 13. In Fig. 13, time unit 1 and time unit 2 are, for example, time slot 1 and time slot 2, respectively.

[0221] For example, in the example shown by reference number a in FIG13 , the first time unit is located in time unit 1, and the second time unit is located in time unit 1 and time unit 2. Therefore, the second time unit includes the first time unit. Therefore, the RIS can transmit the first reference signal within time unit 1 and reflect the second reference signal. Furthermore, the RIS can also reflect the second reference signal within time unit 2. The description of time unit 2, the first reference signal, and the second reference signal can be found in Example 2 and will not be repeated here.

[0222] Based on this example, the network device can estimate the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device based on the signals received during time unit 1. The network device can also estimate the channels of the terminal devices in the second terminal device set based on the signals received during time unit 2. Furthermore, the channel estimation results for the terminal devices in the second terminal device set can be subtracted from the estimated result of the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device to obtain the channel estimation results for the terminal devices in the first terminal device set. Therefore, the channel estimation results for the first terminal device set and the second terminal device set can be accurately and efficiently obtained.

[0223] For another example, in the example shown by reference number b in FIG13 , the first time unit is located in time unit 1 and time unit 2, and the second time unit is located in time unit 1. Therefore, the first time unit includes the second time unit. Therefore, the RIS can transmit the first reference signal within time unit 1 and reflect the second reference signal. Furthermore, the RIS can also transmit the first reference signal within time unit 2. The description of time unit 2, the first reference signal, and the second reference signal can be found in Example 2 and will not be repeated here.

[0224] Based on this example, the network device can estimate the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device based on the signals received during time unit 1. The network device can also estimate the channels of the terminal devices in the first terminal device set based on the signals received during time unit 2. Therefore, the channel estimation results for the terminal devices in the first terminal device set can be obtained by subtracting the channel estimation results for the terminal devices in the first terminal device set from the estimation result of the sum of the channel corresponding to the first terminal device and the channel corresponding to the second terminal device. Therefore, the channel estimation results for the first terminal device set and the second terminal device set can be accurately and efficiently obtained.

[0225] In embodiment 3, time unit 1 can be used for RIS reflection and transmission of reference signals, thereby improving the power utilization of RIS and reducing power loss, thereby improving the channel estimation accuracy.

[0226] Based on the same concept, an embodiment of the present application also provides a communication device. The communication device may include hardware structures and / or software modules corresponding to the functions shown in the above method. Those skilled in the art should easily appreciate that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0227] Figures 14 to 16 are schematic diagrams of the structure of a possible communication device provided in an embodiment of the present application. This communication device can be used to implement the functions of the RIS and / or the first communication device in the above-mentioned method embodiment, thereby also achieving the beneficial effects of the above-mentioned method embodiment. In one possible implementation, the first communication device can be a terminal device or network device as shown in Figure 1. For relevant details and effects, please refer to the description of the above-mentioned embodiment.

[0228] As shown in Figure 14, communication device 1400 includes a processing unit 1410 and a communication unit 1420. Communication unit 1420 can implement corresponding communication functions, and processing unit 1410 is used to process data. Communication unit 1420 can also be a transceiver unit or an input / output interface. Communication device 1400 can be used to implement the functions of the RIS and / or the first communication device in the method embodiments shown in any of Figures 5, 7, or 8 to 10.

[0229] For example, when implementing the RIS function, the processing unit 1410 and / or the communication unit 1420 may be configured to obtain information about the first precoding matrix, information about the second precoding matrix, information about the first time unit, and information about the second time unit.

[0230] Optionally, the communication unit 1420 may further send a first signal to the first communication device in the first time unit via a RIS array for transmitting signals, and / or send a second signal to the second communication device in the second time unit via a RIS array for reflecting signals.

[0231] Optionally, the communication unit 1420 may specifically receive at least one of the first precoding matrix information, the second precoding matrix information, the first time unit information, and the second time unit information.

[0232] Optionally, the communication unit 1420 may also receive power allocation information.

[0233] Optionally, the processing unit 1410 and / or the communication unit 1420 may further obtain information about the third precoding matrix, information about the fourth precoding matrix, information about the third time unit, and information about the fourth time unit.

[0234] Optionally, the communication unit 1420 may further send a third signal to the first communication device in the third time unit via the RIS array for transmitting signals, and / or send a fourth signal to the second communication device in the fourth time unit via the RIS array for reflecting signals.

[0235] For another example, when implementing the function of the first communication device, the communication unit 1420 may be configured to send information of the first precoding matrix, information of the second precoding matrix, information of the first time unit, and information of the second time unit.

[0236] Optionally, the communication unit 1420 may further receive a first signal from the RIS during the first time unit, or send a first signal to the RIS during the first time unit.

[0237] Optionally, the communication unit 1420 may further receive a second signal from the RIS during the second time unit, or send a second signal to the RIS during the second time unit.

[0238] Optionally, the communication unit 1420 may further send the information of the first time unit to the terminal devices in the first terminal device set, and / or send the information of the second time unit to the terminal devices in the second terminal device set.

[0239] Optionally, the communication unit 1420 may also receive information of the first time unit and / or receive information of the second time unit.

[0240] Optionally, the communication unit 1420 may further obtain first channel estimation information of at least one terminal device when the RIS is disabled, and second channel estimation information of the at least one terminal device when the RIS array for transmitting signals is enabled. The processing unit 1410 may further determine, from the at least one terminal device, a terminal device in the first terminal device set based on the first channel estimation information and the second channel estimation information.

[0241] [Corrected 03.07.2023 according to Rule 91] Optionally, the communication unit 1420 may further obtain first channel estimation information of the at least one terminal device when the RIS is disabled, and third channel estimation information of the at least one terminal device when the RIS array for reflecting signals is enabled. The processing unit 1410 may further determine, from the at least one terminal device, a terminal device in the first terminal device set based on the first channel estimation information and the third channel estimation information.

[0242] Optionally, the communication unit 1420 may further send power allocation information to the RIS.

[0243] Optionally, the communication unit 1420 may further send information about the third precoding matrix, information about the fourth precoding matrix, information about the third time unit, and information about the fourth time unit to the RIS.

[0244] Optionally, the communication unit 1420 may further receive a third signal from the RIS in the third time unit, or send a third signal to the RIS in the third time unit.

[0245] Optionally, the communication unit 1420 may further receive a fourth signal from the RIS in the fourth time unit, or send a fourth signal to the RIS in the fourth time unit.

[0246] Optionally, the communication unit 1420 may further send the position information of the RIS array for transmitting the signal and / or the position information of the RIS array for reflecting the signal to the RIS.

[0247] The meanings of the above technologies can be found in the description of the method embodiment section and will not be repeated here.

[0248] It is understood that the division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0249] As shown in Figure 15, a communication device 1500 provided in an embodiment of the present application is used to implement the communication method provided in the present application. The communication device 1500 can be a communication device that applies the communication method, or a component in a communication device, or a device that can be used in conjunction with the communication device. The communication device 1500 can be a network device and / or a terminal device. Specifically, the communication device 1500 can be a chip system or a chip. In the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. The communication device 1500 includes at least one processor 1520 for implementing the communication method provided in the embodiment of the present application. The communication device 1500 can also include an input / output interface 1510, which can include an input interface and / or an output interface. In the embodiment of the present application, the input / output interface 1510 can be used to communicate with other devices via a transmission medium, and its functions may include sending and / or receiving. For example, when the communication device 1500 is a chip, it transmits to other chips or devices via the input / output interface 1510. The processor 1520 can be used to implement the method shown in any of the method embodiments of Figures 5, 7, or 8 to 10.

[0250] Exemplarily, the processor 1520 may be used to execute actions executed by the processing unit 1410 , and the input / output interface 1510 may be used to execute actions executed by the communication unit 1420 , which will not be described in detail.

[0251] Optionally, the communication device 1500 may further include at least one memory 1530 for storing program instructions and / or data. The memory 1530 is coupled to the processor 1520. The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which may be electrical, mechanical, or other forms, and is used for information exchange between devices, units, or modules. The processor 1520 may operate in conjunction with the memory 1530. The processor 1520 may execute program instructions stored in the memory 1530. At least one of the at least one memory may be integrated with the processor.

[0252] In an embodiment of the present application, the memory 1530 may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., or a volatile memory (volatile memory), such as a random-access memory (RAM). A memory is any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto. The memory in the embodiment of the present application may also be a circuit or any other device that can implement a storage function, for storing program instructions and / or data.

[0253] In the embodiments of the present application, the processor 1520 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of the present application may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0254] As shown in Figure 16, a communication device 1600 provided in an embodiment of the present application is used to implement the communication method provided in the present application. The communication device 1600 can be a communication device that applies the communication method shown in the embodiment of the present application, or it can be a component in a communication device, or it can be a device that can be used in combination with a communication device. The communication device 1600 can be a RIS and / or a first communication device. Among them, the communication device 1600 can be a chip system or a chip. In the embodiment of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices. Part or all of the communication methods provided in the above embodiments can be implemented by hardware or by software. When implemented by hardware, the communication device 1600 may include: an input interface circuit 1601, a logic circuit 1602, and an output interface circuit 1603.

[0255] Optionally, taking the device being used to implement the function of the receiving end as an example, the input interface circuit 1601 can be used to execute the above-mentioned receiving action performed by the communication unit 1420, the output interface circuit 1603 can be used to execute the above-mentioned sending action performed by the communication unit 1420, and the logic circuit 1602 can be used to execute the above-mentioned action performed by the processing unit 1410, which will not be repeated.

[0256] Optionally, the communication device 1600 may be a chip or an integrated circuit in specific implementation.

[0257] Part or all of the operations and functions performed by the communication device described in the above method embodiments of the present application can be completed using a chip or an integrated circuit.

[0258] An embodiment of the present application provides a computer-readable storage medium storing a computer program, wherein the computer program includes instructions for executing the above method embodiment.

[0259] An embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the above method embodiment.

[0260] An embodiment of the present application provides a communication system, which includes a first communication device and a RIS, and is used to implement any one of the methods shown in FIG. 5 , FIG. 7 , or FIG. 8 to FIG. 10 .

[0261] 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.

[0262] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, an SSD).

[0263] Note: A portion of this patent application contains material which is subject to copyright protection. The copyright owner reserves all rights reserved except for copies of the materials in the patent file or patent record in the Patent Office.

[0264] The communication devices in the aforementioned apparatus embodiments and the RIS in the method embodiments correspond to the first communication device, with corresponding modules or units performing corresponding steps. For example, the communication unit (transceiver) performs the receiving or sending steps in the method embodiments, while all other steps besides sending and receiving may be performed by the processing unit (processor). The functions of the specific units can be found in the corresponding method embodiments. There may be one or more processors.

[0265] As used in this specification, the terms "component," "module," "system," and the like are used to refer to computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. By way of illustration, both an application running on a computing device and a computing device can be a component. One or more components can reside in a process and / or an execution thread, and a component can be located on one computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable media having various data structures stored thereon. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component across a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0266] Those skilled in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0267] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0268] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0269] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0270] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. If the functions are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable storage medium.

[0271] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: include: The reconfigurable intelligent surface RIS obtains information of a first precoding matrix, information of a second precoding matrix, information of a first time unit, and information of a second time unit, wherein the RIS includes at least one RIS array, each of which is used to transmit signals and / or reflect signals, the first time unit is a signal transmission time unit, the second time unit is a signal reflection time unit, the first precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the first time unit, and the second precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the second time unit.

2. The method according to claim 1, characterized in that The method further comprises: The RIS transmits a first signal to a first communication device in the first time unit through the RIS element for transmitting a signal, and / or transmits a second signal to the first communication device in the second time unit through the RIS element for reflecting a signal.

3. The method according to claim 1, characterized in that Any two precoding matrices in the first precoding matrices are orthogonal, and / or any two precoding matrices in the second precoding matrices are orthogonal.

4. The method according to any one of claims 1 to 3, characterized in that: Any two precoding matrices in the first precoding matrix correspond to different sub-time units in the first time unit, and / or any two precoding matrices in the second precoding matrix correspond to different sub-time units in the second time unit.

5. The method according to any one of claims 1 to 4, characterized in that: The method further comprises: The RIS receives at least one of the first precoding matrix information, the second precoding matrix information, the information of the first time unit, and the information of the second time unit.

6. The method according to any one of claims 1 to 5, characterized in that: The first time unit does not overlap with the second time unit.

7. The method according to any one of claims 1 to 6, characterized in that: At least one of the RIS arrays is used to transmit signals and reflect signals in the first time unit, and is used to transmit signals and reflect signals in the second time unit, and the method further includes: The RIS receives power allocation information, where the power allocation information is used to indicate a power allocation ratio of a transmission signal and a reflection signal of the at least one RIS array.

8. The method according to any one of claims 1 to 5, characterized in that: The first time unit and the second time unit are both time unit 1; The method further comprises: The RIS obtains information about a third precoding matrix, information about a fourth precoding matrix, information about a third time unit, and information about a fourth time unit, wherein the third time unit is a signal transmission time unit, and the fourth time unit is a signal reflection time unit, the third precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the third time unit, and the fourth precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the fourth time unit, the third time unit and the fourth time unit are both time unit 2, the time unit 1 and the time unit 2 do not overlap, at least one RIS array is used for transmitting signals and reflecting signals in the time unit 1 and the time unit 2, and the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition.

9. The method according to claim 8, characterized in that The method further comprises: The RIS transmits a third signal to the first communication device in the third time unit through the RIS element for transmitting a signal, and / or transmits a fourth signal to the first communication device in the fourth time unit through the RIS element for reflecting a signal.

10. The method according to claim 8 or 9, characterized in that The first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition, including: The first precoding matrix, the second precoding matrix, the third precoding matrix and the fourth precoding matrix satisfy: or, in, They respectively represent the first precoding matrix, the third precoding matrix, the second precoding matrix and the fourth precoding matrix.

11. The method according to any one of claims 1 to 5, characterized in that: At least one of the RIS arrays is used to transmit or reflect signals in the first time unit, and is used to transmit or reflect signals in the second time unit, the second time unit includes the first time unit, and the length of the second time unit is greater than the length of the first time unit.

12. The method according to any one of claims 1 to 11, characterized in that: The first time unit and the second time unit belong to the same coherent time.

13. The method according to any one of claims 1 to 12, characterized in that: The method further comprises: The position information of the RIS array for transmitting signals and / or the position information of the RIS array for reflecting signals are received from the network device.

14. A communication method, characterized in that: include: Sending information of a first precoding matrix, information of a second precoding matrix, information of a first time unit, and information of a second time unit to a RIS, wherein the RIS includes at least one RIS array, each of the RIS arrays is used to transmit signals and / or reflect signals, the first time unit is a signal transmission time unit, the second time unit is a signal reflection time unit, the first precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the first time unit, and the second precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the second time unit.

15. The method according to claim 14, characterized in that The method further comprises: receiving a first signal from the RIS during the first time unit, or, A first signal is sent to the RIS during the first time unit.

16. The method according to claim 14 or 15, characterized in that The method further comprises: receiving a second signal from the RIS at the second time unit, or, A second signal is sent to the RIS during the second time unit.

17. The method according to any one of claims 14 to 16, characterized in that: The method further comprises: Sending information of the first time unit to terminal devices in the first terminal device set; and / or, The information of the second time unit is sent to terminal devices in the second terminal device set.

18. The method according to any one of claims 14 to 17, characterized in that: The method further comprises: receiving information of the first time unit; and / or, Receive information about the second time unit.

19. The method according to claim 17, characterized in that The method further comprises: Acquire first channel estimation information of at least one terminal device when the RIS is turned off, and second channel estimation information of the at least one terminal device when the RIS array for transmitting signals is turned on; A terminal device in the first terminal device set is determined from the at least one terminal device according to the first channel estimation information and the second channel estimation information, and the second channel estimation information corresponding to the terminal device in the first terminal device set is better than the first channel estimation information.

20. The method according to claim 17 or 19, characterized in that The method further comprises: Acquire first channel estimation information of at least one terminal device when the RIS is turned off, and third channel estimation information of the at least one terminal device when the RIS array for reflecting signals is turned on; A terminal device in the second terminal device set is determined from the at least one terminal device according to the first channel estimation information and the third channel estimation information, and the third channel estimation information corresponding to the terminal device in the second terminal device set is better than the first channel information.

21. The method according to any one of claims 14 to 20, characterized in that: Any two precoding matrices in the first precoding matrices are orthogonal, and / or any two precoding matrices in the second precoding matrices are orthogonal.

22. The method according to any one of claims 14 to 21, characterized in that: Any two precoding matrices in the first precoding matrix correspond to different sub-time units in the first time unit, and / or any two precoding matrices in the second precoding matrix correspond to different sub-time units in the second time unit.

23. The method according to any one of claims 14 to 22, characterized in that: The first time unit does not overlap with the second time unit.

24. The method according to any one of claims 14 to 23, characterized in that: At least one of the RIS arrays is used to transmit signals and reflect signals in the first time unit, and is used to transmit signals and reflect signals in the second time unit, and the method further includes: Power allocation information is sent to the RIS, where the power allocation information is used to indicate a power allocation ratio of a transmission signal and a reflection signal of the at least one RIS array.

25. The method according to any one of claims 14 to 24, characterized in that: The first time unit and the second time unit are both time unit 1; The method further comprises: Send information of a third precoding matrix, information of a fourth precoding matrix, information of a third time unit, and information of a fourth time unit to the RIS, wherein the third time unit is a signal transmission time unit, and the fourth time unit is a signal reflection time unit, the third precoding matrix is ​​one or more precoding matrices used by the RIS array for transmitting signals in the third time unit, the fourth precoding matrix is ​​one or more precoding matrices used by the RIS array for reflecting signals in the fourth time unit, the third time unit and the fourth time unit are both time unit 2, the time unit 1 and the time unit 2 do not overlap, at least one RIS array is used for transmitting signals and reflecting signals in the time unit 1 and the time unit 2, and the first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition.

26. The method of claim 25, wherein: The method further comprises: receiving a third signal from the RIS at the third time unit, or, A third signal is sent to the RIS at the third time unit.

27. The method according to claim 25 or 26, characterized in that The method further comprises: receiving a fourth signal from the RIS at the fourth time unit, or, A fourth signal is sent to the RIS at the fourth time unit.

28. The method according to any one of claims 25 to 27, characterized in that: The first precoding matrix, the second precoding matrix, the third precoding matrix, and the fourth precoding matrix satisfy a spatial orthogonality condition, including: The first precoding matrix, the second precoding matrix, the third precoding matrix and the fourth precoding matrix satisfy: or, in, They respectively represent the first precoding matrix, the third precoding matrix, the second precoding matrix and the fourth precoding matrix.

29. The method according to any one of claims 14 to 22, characterized in that: At least one of the RIS arrays is used to transmit or reflect signals in the first time unit, and is used to transmit or reflect signals in the second time unit, the second time unit includes the first time unit, and the length of the second time unit is greater than the length of the first time unit.

30. The method according to any one of claims 14 to 29, characterized in that: The first time unit and the second time unit belong to the same coherent time.

31. The method according to any one of claims 14 to 30, characterized in that: The method further comprises: The position information of the RIS array for transmitting signals and / or the position information of the RIS array for reflecting signals are sent to the RIS.

32. A processing device, characterized in that: The method comprises a processor configured to execute a computer program or instructions to implement the method according to any one of claims 1 to 31.

33. The device according to claim 32, characterized in that The device further comprises a memory and / or a transceiver, wherein the memory is used to store the computer program or instructions, and the transceiver is used for the device to communicate.

34. A communication device, characterized in that: Comprising modules for executing the method as claimed in any one of claims 1 to 31.

35. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or instruction. When the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 31 is implemented.

36. A computer program product, characterized in that The method comprises a computer program or an instruction, which, when executed by a computer, causes the computer to implement the method according to any one of claims 1 to 31.

37. A communication system, characterized in that: Comprising a communication device for executing the method as claimed in any one of claims 1 to 13, and a communication device for executing the method as claimed in any one of claims 14 to 31.

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