Secure communication method, and apparatus

Abstract

The present application relates to the technical field of communications, and particularly relates to a secure communication method, and an apparatus, which aim to realize secure communication without increasing additional power and resource overheads. The method comprises: a first communication apparatus encoding N data blocks on the basis of an encoding matrix, so as to obtain N encoded data blocks, wherein N is an integer greater than or equal to 2; for an i-th encoded data block among the N encoded data blocks, on the basis of a spatial pattern selection parameter corresponding to the i-th encoded data block, determining, from among K spatial patterns corresponding to a RIS, a target spatial pattern corresponding to the i-th encoded data block, wherein i is 1, 2, ..., N, and K is an integer greater than or equal to 2; and sending the i-th encoded data block to a second communication apparatus by means of the target spatial pattern corresponding to the i-th encoded data block.

Description

A secure communication method and device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411187544.3, filed on August 27, 2024, entitled "A Secure Communication Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a secure communication method and apparatus. Background Technology

[0004] A reconfigurable intelligent surface (RIS) is a reflective surface composed of a series of passive reflective elements. Each passive reflective element can add a specific phase to the received electromagnetic wave before reflecting it back. Since the added phase of the reflective element can be designed and controlled according to certain rules, the electromagnetic waves reflected by the RIS may achieve coherent superposition after phase design, thereby enhancing the energy of the electromagnetic wave received by the receiver.

[0005] The working principle of a Resonant Radiation System (RIS) is somewhat similar to beamforming in a multi-antenna system. After phase design, RIS can form several physical beams in a specific direction in space, thereby achieving directional energy transmission. Based on RIS's ability to achieve directional energy transmission, it can realize the directional distribution of electromagnetic wave energy in space. Therefore, RIS has the potential for application in secure communication scenarios. For example, when the approximate location of a third-party user (also known as an unauthorized user) is known on the legitimate link, the legitimate link transmitter can transmit artificial noise signals to the RIS. Simultaneously, the legitimate link controls the RIS to aim the beam reflecting the artificial noise signal at the approximate location of the third-party user, thereby reducing its received signal-to-noise ratio and preventing it from correctly demodulating the legitimate signal.

[0006] However, under the constraint of constant total power of the legitimate link, the security mechanism based on reducing the signal-to-noise ratio received by third-party users will occupy part of the legitimate link's transmit power. In addition, in order for the RIS to reflect artificial noise signals to third-party users, the legitimate link needs to know the approximate spatial location of the third-party users in advance, which will also bring additional resource overhead. Summary of the Invention

[0007] This application provides a secure communication method and apparatus, aiming to achieve secure communication without increasing additional power or resource overhead.

[0008] In a first aspect, embodiments of this application provide a secure communication method, which can be executed by a first communication device. The method includes: encoding N data blocks according to an encoding matrix to obtain N encoded data blocks, where N is an integer greater than or equal to 2; for the i-th encoded data block among the N encoded data blocks, determining the target spatial mode corresponding to the i-th encoded data block from among K spatial modes corresponding to RIS according to the spatial mode selection parameter corresponding to the i-th encoded data block, where i is 1, 2, ..., N, and K is an integer greater than or equal to 2; and sending the i-th encoded data block to a second communication device through the target spatial mode corresponding to the i-th encoded data block.

[0009] In the aforementioned secure communication method, the first communication device and the second communication device are different communication devices. The first communication device (or the second communication device) can be a terminal device, a component of a terminal device (e.g., a processor, chip, or chip system), or a device used in conjunction with a terminal device. It can also be a network device, a component of a network device (e.g., a processor, chip, or chip system), or a device used in conjunction with a network device. For example: the first communication device can be a network device, and the second communication device can be a terminal device; or the first communication device can be a terminal device, and the second communication device can be another terminal device; or the first communication device can be a network device, and the second communication device can be another network device, etc.

[0010] Using the above method, when the first communication device and the second communication device communicate, the first communication device can encode the original N data blocks. When transmitting each encoded data block, a spatial mode is selected from K spatial modes for the transmission of the encoded data block. In this way, a third-party user can only correctly receive the encoded data block and demodulate part of the original data block if they correctly determine which spatial mode each encoded data block was transmitted through. This increases the security of communication between the first communication device and the second communication device without increasing additional power or resource overhead.

[0011] In one possible design, transmitting the i-th coded data block to the second communication device via the target space mode corresponding to the i-th coded data block includes: determining the transmission rate based on the channel quality of the target space mode corresponding to the i-th coded data block; and transmitting the i-th coded data block to the second communication device via the target space mode corresponding to the i-th coded data block based on the transmission rate.

[0012] The above design allows the transmission rate to be determined based on channel quality (such as signal-to-noise ratio or channel capacity), making the transmission rate more compatible with the channel and improving the efficiency and reliability of data transmission. When the channel quality is good, a higher transmission rate can be used, further increasing the difficulty for third-party users to receive encoded data blocks and reducing the probability of information leakage.

[0013] In one possible design, the spatial mode selection parameters include a key. Based on the spatial mode selection parameters corresponding to the i-th encoded data block, the target spatial mode corresponding to the i-th encoded data block is determined from among the K spatial modes corresponding to RIS. This includes: determining the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes based on the key in the key stream corresponding to the i-th encoded data block, wherein the key stream is derived from the root key used for communication with the second communication device.

[0014] The above design allows for the reuse of existing key derivation processes between the first and second communication devices, protecting the communication security of legitimate links between the first and second communication devices without incurring additional security overhead.

[0015] In one possible design, the spatial mode selection parameters include a spatial mode index. Before determining the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block, the method further includes: sending pilot signals to the second communication device through the K spatial modes respectively; receiving the spatial mode index from the second communication device, the spatial mode index being determined based on the channel parameters of the second communication device receiving the pilot signals through the K spatial modes respectively, and the spatial mode index being used to identify the target spatial mode corresponding to the i-th coded data block.

[0016] The above design allows for the selection of the target spatial mode for transmitting coded data blocks based on channel estimation results, which helps improve the reliability of coded data block transmission.

[0017] In one possible design, the method further includes: receiving channel parameters and / or channel capacity of a spatial mode corresponding to a spatial mode index from a second communication device, wherein the channel parameters and / or channel capacity are used to determine the channel quality of the spatial mode corresponding to the spatial mode index.

[0018] The above design facilitates the first communication device in obtaining the channel quality of the target spatial pattern of the transmitted coded data block, and in adjusting the transmission rate based on the channel quality, thereby improving the reliability of the coded data block transmission.

[0019] In one possible design, the spatial mode selection parameters include channel parameters. Based on the spatial mode selection parameters corresponding to the i-th coded data block, the target spatial mode corresponding to the i-th coded data block is determined from among the K spatial modes corresponding to RIS. This includes: determining the channel parameters corresponding to each of the K spatial modes; and determining the target spatial mode corresponding to the i-th coded data block from among the K spatial modes based on the channel parameters corresponding to each of the K spatial modes.

[0020] The above design allows the target spatial mode for transmitting coded data blocks to be determined based on the channel parameters of K spatial modes. This can protect the communication security of the legitimate link between the first and second communication devices without adding extra security overhead.

[0021] In one possible design, the encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

[0022] Through the above design, the vector group consisting of any N-2 row vectors and any 1 unit vector in the coding matrix is ​​linearly independent, which means that a third-party user must correctly receive N-1 coded data blocks (i.e. demodulate at least N-1 coded data blocks from the received signal) in order to decode at least one original data block.

[0023] In one possible design, K is determined based on the number of RIS R and the number of available spatial beam directions D for each RIS configuration, for example, K = R * D.

[0024] The above design allows for the accurate determination of the number of spatial patterns existing in the communication environment of the first and second communication devices.

[0025] Secondly, embodiments of this application provide a secure communication method, which can be executed by a second communication device. The method includes: for the i-th coded data block among N coded data blocks, determining the target spatial mode corresponding to the i-th coded data block from among K spatial modes corresponding to RIS according to the spatial mode selection parameter corresponding to the i-th coded data block, where i is 1, 2, ..., N, and N and K are integers greater than or equal to 2; receiving the i-th coded data block from a first communication device through the target spatial mode corresponding to the i-th coded data block; and decoding the N coded data blocks according to the encoding matrix to obtain N data blocks.

[0026] In the aforementioned secure communication method, the first communication device and the second communication device are different communication devices. The first communication device (or the second communication device) can be a terminal device, a component of a terminal device (e.g., a processor, chip, or chip system), or a device used in conjunction with a terminal device. It can also be a network device, a component of a network device (e.g., a processor, chip, or chip system), or a device used in conjunction with a network device. For example: the first communication device can be a network device, and the second communication device can be a terminal device; or the first communication device can be a terminal device, and the second communication device can be another terminal device; or the first communication device can be a network device, and the second communication device can be another network device, etc.

[0027] In one possible design, receiving the i-th coded data block from the first communication device via the target space pattern corresponding to the i-th coded data block includes: aligning the receiving antenna with the RIS beam direction corresponding to the target space pattern to receive the i-th coded data block from the first communication device.

[0028] In one possible design, the spatial mode selection parameters include a key. Based on the spatial mode selection parameters corresponding to the i-th encoded data block, the target spatial mode corresponding to the i-th encoded data block is determined from among the K spatial modes corresponding to RIS. This includes: determining the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes based on the key corresponding to the i-th encoded data block in the key stream, wherein the key stream is derived from the root key used for communication with the first communication device.

[0029] In one possible design, the spatial mode selection parameter includes a spatial mode index, and the method further includes: receiving pilot signals from the first communication device through K spatial modes respectively; determining the spatial mode index according to the channel parameters of the pilot signals received through the K spatial modes respectively, wherein the spatial mode index is used to identify the target spatial mode corresponding to the i-th coded data block; and sending the spatial mode index to the first communication device.

[0030] In one possible design, the method further includes sending channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index to the first communication device.

[0031] In one possible design, the spatial mode selection parameters include channel parameters. Based on the spatial mode selection parameters corresponding to the i-th coded data block, the target spatial mode corresponding to the i-th coded data block is determined from among the K spatial modes corresponding to RIS. This includes: determining the channel parameters corresponding to each of the K spatial modes; and determining the target spatial mode corresponding to the i-th coded data block from among the K spatial modes based on the channel parameters corresponding to each of the K spatial modes.

[0032] In one possible design, the encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

[0033] In one possible design, K is determined based on the number of RIS R and the number of available spatial beam directions D for each RIS configuration.

[0034] Thirdly, embodiments of this application provide a communication device that has the function of implementing the methods described in the first or second aspect above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions, such as an interface unit and a processing unit.

[0035] In one possible design, the device can be a chip or an integrated circuit.

[0036] In one possible design, the device includes a memory and a processor, the memory for storing instructions executed by the processor, and when the instructions are executed by the processor, the device can perform the method of the first aspect or the second aspect.

[0037] Fourthly, embodiments of this application provide a communication device, which includes an interface circuit and a processor, with the processor and the interface circuit coupled to each other. The interface circuit is used for inputting and / or outputting signals, and the processor uses logic circuits or executing instructions to implement the methods of the first or second aspect described above. It is understood that the interface circuit can be a transceiver, a transceiver device, or an input / output interface.

[0038] Optionally, the communication device may also include a memory for storing instructions executed by the processor, or storing input data required by the processor to execute instructions, or storing data generated after the processor executes instructions. The memory may be a physically independent unit, or it may be coupled to the processor, or the processor may include the memory (i.e., the processor and the memory are integrated together).

[0039] In one possible implementation, the communication device is a chip.

[0040] Fifthly, embodiments of this application provide a communication system, which includes a first communication device and a second communication device. The first communication device can be used to implement the method described in the first aspect; the second communication device can be used to implement the method described in the second aspect.

[0041] In a sixth aspect, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions, which, when executed by a processor, can implement the methods described in the first or second aspect.

[0042] In a seventh aspect, embodiments of this application also provide a computer program product, including a computer program or instructions, which, when executed by a processor, can implement the methods described in the first or second aspect.

[0043] Eighthly, embodiments of this application also provide a chip system including a processor, the processor being coupled to a memory, the memory being used to store programs or instructions, and when the program or instructions are executed by the processor, the methods of the first or second aspect described above can be implemented.

[0044] The technical effects achievable by aspects two through eight above are similar to those achievable by aspect one above, and will not be repeated here. Attached Figure Description

[0045] Figure 1 is a schematic diagram of the architecture of the communication system provided in an embodiment of this application;

[0046] Figure 2 is a schematic diagram of RIS-based communication provided in an embodiment of this application;

[0047] Figure 3 is a schematic diagram of the application scenario provided in the embodiments of this application;

[0048] Figure 4 is a schematic diagram of a secure communication method provided in an embodiment of this application;

[0049] Figure 5 is a schematic diagram showing the relationship between the probability of information leakage and the number of spatial patterns provided in the embodiments of this application;

[0050] Figure 6 is a schematic diagram illustrating the relationship between the probability of information leakage and the number of data blocks provided in the embodiments of this application;

[0051] Figures 7 and 8 are schematic diagrams of the communication device provided in the embodiments of this application. Detailed Implementation

[0052] The technical solutions of this application can be applied to various communication systems, such as: Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, Universal Mobile Telecommunications System (UMTS), 5th Generation (5G) mobile communication systems, Beyond 5G (B5G) mobile communication systems, or 6th Generation (6G) and other communication systems evolved after 5G. The communication system can also be a device-to-device (D2D) network, a WiFi network, a machine-to-machine (M2M) network, an Internet of Things (IoT) network, or other networks.

[0053] The architecture of the communication system used in this embodiment is shown in Figure 1. The communication system 1000 includes a radio access network (RAN) 100 and a core network (CN) 200. Optionally, the communication system 1000 may also include an Internet 300. The RAN 100 includes at least one network device (110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal device (120a-120j in Figure 1, collectively referred to as 120). The RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). The terminal device 120 is wirelessly connected to the network device 110. The network device 110 is wirelessly or wiredly connected to the core network 200. The core network device in the core network 200 and the network device 110 in the RAN 100 may be different physical devices, or they may be the same physical device integrating core network logical functions and radio access network logical functions.

[0054] RAN 100 can be a cellular system related to the 3rd Generation Partnership Project (3GPP), such as 4G, 5G, or evolution systems beyond 5G (i.e., future mobile communication systems). RAN 100 can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a WiFi system. RAN 100 can also be a communication system that integrates two or more of the above systems.

[0055] The apparatus provided in this application embodiment can be applied to network device 110 or terminal device 120. It is understood that Figure 1 only illustrates one possible communication system architecture applicable to this application embodiment; in other possible scenarios, the communication system architecture may also include other devices.

[0056] Network device 110 is a node in the radio access network (RAN), also known as an access network device or an RAN node (or device). Network device 110 assists terminal devices in achieving wireless access. Multiple network devices 110 in the communication system 1000 can be nodes of the same type or different types. In some scenarios, the roles of network device 110 and terminal device 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminal devices 120j accessing RAN 100 through network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal device. Network device 110 and terminal device 120 are sometimes referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functions, and network elements 120a-120j can be understood as communication devices with terminal device functions.

[0057] In one possible scenario, network equipment can be a base station (BS), an evolved NodeB (eNodeB), a transmitting and receiving point (TRP), a transmitting point (TP), a next-generation NodeB (gNB), a base station in a future mobile communication system, a satellite, or an access point (AP) in a WiFi system, an integrated access and backhaul (IAB) node, or network equipment in a mobile switching center non-terrestrial network (NTN) communication system, i.e., it can be deployed on a high-altitude platform or satellite, etc. Network equipment can be a macro base station (as shown in Figure 1, 110a), a micro base station or indoor station (as shown in Figure 1, 110b), a relay node or donor node, or a radio controller in a CRAN scenario. Network equipment can also act as a base station in device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, drone communication, and machine-to-machine (M2M) communication. Optionally, network equipment can also be a server, wearable device, vehicle, or in-vehicle equipment, etc. For example, the access network equipment in vehicle-to-everything (V2X) technology can be a roadside unit (RSU).

[0058] In another possible scenario, multiple network devices collaborate to assist terminal devices in achieving wireless access, with each network device performing a portion of the base station's functions. For example, network devices can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs). CUs and DUs can be separate entities or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio equipment or radio units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). It is understood that network devices can be CU nodes, DU nodes, or devices comprising both CU and DU nodes. Furthermore, CUs can be classified as network devices in the access network (RAN) or the core network (CN), without limitation.

[0059] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an ORAN system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules.

[0060] In this embodiment, the form of the network device is not limited. The device used to implement the function of the network device can be the network device itself, or it can be a device that supports the network device in implementing the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device.

[0061] Terminal equipment 120, also known as terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), etc., is a device used to provide voice or data connectivity to users. It can also be an Internet of Things (IoT) device or a station (STA) in a WiFi system. For example, terminal equipment includes handheld devices with wireless connectivity, vehicle-mounted devices, etc. Currently, terminal devices can include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices (such as smartwatches, smart bracelets, pedometers, smart glasses, etc.), in-vehicle equipment (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), wireless terminals in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminals in autonomous driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, and flying equipment (such as smart robots, hot air balloons, drones, airplanes), etc. Terminal devices can also be other devices with terminal functions; for example, a terminal device can also be a device that performs terminal functions in D2D communication.

[0062] The embodiments of this application do not limit the device form of the terminal device. The device used to implement the function of the terminal device can be the terminal device itself; it can also be a device that supports the terminal device in implementing the function, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In the embodiments of this application, the chip system can be composed of chips or can include chips and other discrete components.

[0063] Reconfigurable intelligent surfaces (RIS) are a candidate technology for next-generation communication systems. They are also known as reconfigurable intelligent meta-surfaces, reconfigurable reflective surfaces, reflective surfaces, or reflective units. A RIS is a reflective surface composed of a series of passive reflective units. Each passive reflective unit can add a specific phase to the received electromagnetic wave before reflecting it. Because the added phase of the reflective units can be designed and controlled according to certain rules, the electromagnetic waves reflected by the RIS may achieve coherent superposition after phase design, thereby enhancing the energy of the electromagnetic waves received by the receiver. The introduction of RIS can enhance communication performance and expand the coverage of wireless networks. For example, Figure 2 shows a communication schematic based on a RIS, where the communication source is a terminal device and the target is a network device. RIS can create a virtual line-of-sight (LoS) propagation path between the communication source and the target, avoiding interference from obstacles between them.

[0064] The working principle of reconfigurable smart surfaces is somewhat similar to beamforming in multi-antenna systems. After phase design, reconfigurable smart surfaces can form several physical beams in specific directions in space, thereby achieving directional energy transmission. Based on the characteristic of reconfigurable smart surfaces to achieve directional energy transmission, the directional distribution of electromagnetic wave energy in space can be realized. Therefore, reconfigurable smart surfaces have the potential to be applied in secure communication scenarios.

[0065] One approach is to control a reconfigurable smart surface to align the beam direction with the legitimate link receiver when its location is known. This concentrates electromagnetic energy in the direction of the legitimate link receiver, minimizing electromagnetic energy leakage to third-party users (also known as unauthorized users) and thus reducing the signal-to-noise ratio (SNR) of the received signal. However, this approach only worsens the SNR of the received signal for the third-party user. If the third-party user's receiving capability is strong enough, the channel conditions are good enough, or the communication system uses low-order modulation, the third-party user may still demodulate part of the signal and obtain some data, making it insecure.

[0066] Another approach is that, when the approximate location of the third-party user is known on the legitimate link, the legitimate link transmitter can transmit artificial noise signals to the RIS in addition to transmitting normal signals. Simultaneously, besides controlling the RIS to reflect normal signals to the legitimate link receiver, the legitimate link can also control the RIS to aim the beam of the reflected artificial noise signal (i.e., jamming signal) at the approximate location of the third-party user, causing the third-party user to receive the artificial noise signal, thereby reducing its received signal-to-noise ratio and preventing it from correctly demodulating the legitimate signal.

[0067] However, under the constraint of constant total power of the legitimate link, the security mechanism based on reducing the signal-to-noise ratio received by third-party users will occupy part of the legitimate link's transmit power. In addition, in order for the RIS to reflect artificial noise signals to third-party users, the legitimate link needs to know the approximate spatial location of the third-party users in advance, which will bring additional resource overhead, and it is difficult to determine the spatial location of third-party users in practical application scenarios.

[0068] Based on this, this application provides a secure communication method and apparatus. Considering that there can be R RIS in the environment, and each RIS can be configured with D available spatial beam directions, then the RIS in the environment corresponds to K = R × D available RIS beam directions, and the legitimate link has K available RIS beam directions, where each RIS beam direction can be called a spatial mode. When transmitting each data block, the legitimate link can select one from the K spatial modes to transmit the data block, thereby enhancing the signal-to-noise ratio of the legitimate link and preventing all legitimate link data blocks from being transmitted through the same spatial mode. This forces third-party users to guess the spatial mode (i.e., the RIS beam direction corresponding to the data block) when obtaining legitimate link data blocks, and the third-party user's link channel capacity needs to be higher than the legitimate link channel capacity to correctly demodulate the legitimate link data blocks, so as to achieve secure communication without increasing additional power and resource overhead. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0069] Figure 3 is a schematic diagram of a possible application scenario provided by an embodiment of this application. The environment includes multiple RIS (Reference Provider Identifiers). The first communication device (taking a network device as an example in Figure 3) can execute the secure communication method provided by this embodiment of the application to send data blocks (also referred to as signals, data, or information) to the second communication device (taking terminal device 1 as an example in Figure 3) through the RIS, so as to avoid the data carried in the data blocks from being leaked to third-party users (taking terminal device 2 as an example in Figure 3). It is understood that the first communication device, the second communication device, etc. (or the transmitter or receiver of the first communication device, the second communication device, etc.) can be equipped with a single antenna or multiple antennas, and this application does not limit this.

[0070] Furthermore, it should be understood that the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects, and are not used to limit the size, content, order, timing, priority, or importance of the multiple objects. For example, "first communication device" and "second communication device" do not indicate a difference in priority or importance between the two communication devices.

[0071] In this application embodiment, the number of nouns, unless otherwise specified, refers to "singular nouns or plural nouns," that is, "one or more." "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0072] The secure communication method provided in this application can be executed by a first communication device and a second communication device, wherein the first communication device and the second communication device are different communication devices. The first communication device (or the second communication device) can be a terminal device, a component of a terminal device (e.g., a processor, chip, or chip system), or a device used in conjunction with a terminal device. It can also be a network device, a component of a network device (e.g., a processor, chip, or chip system), or a device used in conjunction with a network device. For example: the first communication device can be a network device and the second communication device can be a terminal device; or the first communication device can be a terminal device and the second communication device can be another terminal device; or the first communication device can be a network device and the second communication device can be another network device, etc.

[0073] Figure 4 is a schematic diagram of a secure communication method provided in an embodiment of this application. The method includes:

[0074] S401: The first communication device encodes N data blocks according to the encoding matrix to obtain N encoded data blocks. Wherein, N is an integer greater than or equal to 2.

[0075] In this embodiment of the application, to prevent data blocks from being directly obtained by third-party users and to improve the security of data block transmission, the first communication device can encode the N data blocks according to the encoding matrix before sending N data blocks, resulting in N encoded data blocks. Thus, even if a third-party user receives some encoded data blocks (or a signal modulated or carrying some encoded data blocks), because the encoded data blocks have undergone encoding processing, the third-party user cannot directly obtain the original data blocks, thereby improving the security of data block transmission.

[0076] The size of the data block and the encoding matrix used can be pre-configured in the first and second communication devices, for example, by predefining them through protocols and configuring them in the first and second communication devices; alternatively, they can be determined through negotiation between the first and second communication devices, for example, by the first communication device and then sent to the second communication device. This application does not limit the size of the data block, the encoding matrix used, or the method by which the first and second communication devices determine the size of the data block and the encoding matrix.

[0077] As an example: N data blocks can be represented as M = (m1, m2, ..., m N ) T Where m1, m2, ..., m N Let m1 represent the first data block (or the data block with index or number 1) of the N data blocks, m2 represent the second data block (or the data block with index or number 2) of the N data blocks, ..., m N Let X represent the Nth data block (or the data block with index or number N) out of N data blocks, and M represent the matrix corresponding to the N data blocks. Let the encoding matrix be A. The N encoded data blocks after encoding by the encoding matrix A can be represented as: X = (x1, x2, ..., x...). N ) T =AM, where x1,x2,…,x N Let x1 represent the first coded data block (or the coded data block with index or number 1) and x2 represent the second coded data block (or the coded data block with index or number 2) and so on. N Let X represent the Nth encoded data block (or the encoded data block with index or number N) out of N encoded data blocks, and let X represent the matrix corresponding to the N encoded data blocks.

[0078] In one possible implementation, the encoding matrix A is invertible, so that the receiver of the legitimate link (such as a second communication device) can correctly decode the original N data blocks M = A after receiving N encoded data blocks. -1 X.

[0079] In one possible implementation, the encoding matrix A is an N*N matrix. Any N-2 row vectors and any one unit vector in the encoding matrix A form a linearly independent vector group. Therefore, a third-party user must correctly receive N-1 encoded data blocks (i.e., demodulate at least N-1 encoded data blocks from the received signal) to decode at least one original data block, thereby improving data transmission security. This is because when a third-party user demodulates N-2 encoded data blocks from the received signal, since the vector group formed by any N-2 row vectors and any one unit vector in the encoding matrix A is linearly independent, the third-party user cannot obtain any single unit vector by linearly combining these N-2 encoded data blocks with arbitrary coefficients. That is, the third-party user can only obtain linear combinations of several original data blocks in the form of m1+m2+…, but cannot obtain any single original data block m1,m2,… and thus cannot decode at least one original data block.

[0080] Taking N=6 as an example, the encoding matrix A can be as follows: any N-2 row vectors and any 1 unit vector of the encoding matrix A form a vector group that is linearly independent.

[0081] S402A: For the i-th coded data block among N coded data blocks, the first communication device determines the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block.

[0082] S402B: For the i-th coded data block among N coded data blocks, the second communication device determines the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block.

[0083] Where i is 1, 2, ..., N, and N and K are integers greater than or equal to 2.

[0084] It should be noted that step S402B can be executed before step S401A, after step S402A, or simultaneously with step S402A. This application limits the order in which the first communication device executes step S402A and the second communication device executes step S402B.

[0085] In the communication environment of the first communication device and the second communication device, there can be R RIS. Each RIS can be configured with D available spatial beam directions. Then, there are K = R × D available RIS beam directions in the environment. Each RIS beam direction can be called a spatial mode. That is to say, there are K spatial modes corresponding to RIS.

[0086] The information such as the number of RIS K, the number of available spatial beam directions D configured for each RIS, the location of each RIS, the index of the K spatial modes, and the configuration information of the RIS beams corresponding to the K spatial modes (such as RIS beam directions) can be pre-configured in the first and second communication devices, or can be determined interactively by the first and second communication devices through signaling such as radio resource control (RRC) reconfiguration, downlink control information (DCI), and media access control (MAC) control element (MAC CE). This application does not limit this.

[0087] When transmitting each coded data block, the first communication device can determine a target spatial pattern from K spatial patterns as the target spatial pattern corresponding to that coded data block. Taking the coded data block as the i-th coded data block among N coded data blocks, the first communication device can determine the target spatial pattern corresponding to the i-th coded data block from the K spatial patterns in the following manner.

[0088] Method A: The spatial selection parameters include a key. The first communication device determines the target spatial pattern corresponding to the i-th encoded data block from among K spatial patterns based on the key corresponding to the i-th encoded data block in the key stream. The key stream can be derived from the root key used by the first communication device and the second communication device for communication.

[0089] As an example: After the first and second communication devices negotiate the root key for communication, the first communication device can derive a keystream based on the root key. Each key in the keystream can be used to determine the target space pattern corresponding to an encoded data block. For example, the (P+i)th key in the keystream is used to determine the target space pattern corresponding to the ith encoded data block, etc., where P is an integer greater than or equal to 0. The key derivation algorithm can be a pseudo-random number generator (PRNG), a password-based key derivation function 2 (PBKDF2), etc.

[0090] In one possible implementation, at least b = [logK] bits are needed to determine the target spatial pattern corresponding to the i-th coded data block for K spatial patterns. For example, if K = 10, then b = 4, and the target spatial pattern corresponding to the i-th coded data block can be determined using 4 bits in the key.

[0091] For example, the first communication device can use the first 4 bits, the last 4 bits, or the 4n+1 (n = 0, 1, 2, 3) bits of the key corresponding to the i-th coded data block in the key stream to determine the target spatial pattern corresponding to the i-th coded data block. Taking the indices of K (K = 10) spatial patterns as 1, 2, 3, ..., K as an example, if 4 bits are 0001, the first communication device can determine that the target spatial pattern corresponding to the i-th coded data block is the spatial pattern with index 1; if 4 bits are 0010, the first communication device can determine that the target spatial pattern corresponding to the i-th coded data block is the spatial pattern with index 2; if 4 bits are 0011, the first communication device can determine that the target spatial pattern corresponding to the i-th coded data block is the spatial pattern with index 3, and so on.

[0092] Furthermore, the key stream for the first and second communication devices can be obtained by reusing existing key derivation architectures. For example, the first and second communication devices can reuse the signaling plane and user plane key stream derivation architectures, and the key stream can be a key (K) applied to RRC integrity protection. RRCint The key stream of , etc.

[0093] The implementation of the second communication device in determining the target space mode corresponding to the i-th coded data block can be referred to the implementation of the first communication device in determining the target space mode corresponding to the i-th coded data block, and will not be elaborated further.

[0094] It is also understandable that the aforementioned root key can be replaced with a string agreed upon (or negotiated and determined) by the first and second communication devices, or a random number, etc.

[0095] Method B: The spatial selection parameters include the current time. Based on the current time, the first communication device determines the target spatial mode corresponding to the i-th coded data block from among K spatial modes.

[0096] As an example: the first communication device can generate a sequence based on the current time using a set hash algorithm or message digest algorithm, and determine the target space pattern corresponding to the i-th encoded data block based on a set number of bits in the sequence (e.g., b = [logK] bits). Similarly, the second communication device, which is time-synchronized with the first communication device, can also generate a sequence based on the current time using a set hash algorithm or message digest algorithm, and determine the target space pattern corresponding to the i-th encoded data block based on a set number of bits in the sequence (e.g., b = [logK] bits).

[0097] Method C: The spatial mode selection parameter includes the spatial mode index. The first communication device can determine the target spatial mode corresponding to the i-th coded data block from among K spatial modes based on the spatial mode index corresponding to the i-th coded data block.

[0098] As an example: Before sending the i-th coded data block, the first communication device can send pilot signals (also called pilots or reference signals) to the second communication device through K spatial modes. The second communication device can receive the pilot signals from the first communication device through the K spatial modes to obtain the channel parameters of the pilot signals received by the K spatial modes respectively. The channel parameters may include one or more of the following: signal received power, signal-to-noise ratio, etc. The second communication device can determine the target spatial mode corresponding to the i-th coded data block based on the channel parameters of the pilot signals received by the K spatial modes (for example, the spatial mode with the largest corresponding channel parameters (such as signal received power or signal-to-noise ratio) among the K spatial modes is taken as the target spatial mode), and send the spatial mode index corresponding to the target spatial mode to the first communication device. The first communication device can determine the target spatial mode corresponding to the i-th coded data block based on the spatial mode index.

[0099] In one possible implementation, to improve communication security, the spatial pattern index can be encrypted by the second communication device using an encryption key and then sent to the first communication device. Upon receiving the encrypted spatial pattern index, the first communication device can decrypt it using a decryption key. The encryption and decryption keys can be symmetric or asymmetric keys, and can be determined through negotiation between the first and second communication devices.

[0100] In some implementations, the second communication device may also send the channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index to the first communication device. These channel parameters and / or channel capacity can be used by the first communication device to determine the transmission rate, etc.

[0101] Method D: The spatial mode selection parameters include channel parameters. The first communication device can determine the channel parameters corresponding to each of the K spatial modes. Based on the channel parameters corresponding to each of the K spatial modes, the target spatial mode corresponding to the i-th coded data block is determined among the K spatial modes.

[0102] As an example: Before sending the i-th coded data block, the first communication device can receive signals (such as pilot signals or data signals) from the second communication device through K spatial modes respectively, and obtain the channel parameters h1, h2, ..., h corresponding to the K spatial modes respectively. K Based on the channel parameters corresponding to the K spatial modes, and according to a set selection method (such as selecting the spatial mode with the largest corresponding channel parameter value or the spatial mode with the largest corresponding channel parameter modulus, etc.), the target spatial mode corresponding to the i-th coded data block is selected from the K spatial modes. For example, the first communication device can select the target spatial mode corresponding to the channel parameters h1, h2, ..., h1 of the K spatial modes respectively. K Sort by modulo values, when the sorting result is |h1|>|h2|>…>|h K-1 |>|h K When |, the first communication device can select the spatial mode corresponding to h1 as the target spatial mode corresponding to the i-th coded data block.

[0103] Because the uplink and downlink channels are distinct, the second communication device can obtain the channel parameters corresponding to the K spatial modes by receiving signals (such as pilot signals or data signals) from the first communication device through K spatial modes respectively. The channel parameters corresponding to the K spatial modes obtained by the second communication device are the same as or similar to the channel parameters corresponding to the K spatial modes obtained by the first communication device by receiving signals from the second device through K spatial modes respectively. Therefore, after obtaining the channel parameters corresponding to the K spatial modes, the second communication device can also select the target spatial mode corresponding to the i-th coded data block from the K spatial modes according to the same selection method as the first communication device.

[0104] S403: The first communication device sends the i-th coded data block to the second communication device through the target space mode corresponding to the i-th coded data block. Correspondingly, the second communication device receives the i-th coded data block from the first communication device through the target space mode corresponding to the i-th coded data block.

[0105] As an example: For the i-th coded data block out of N coded data blocks, the first communication device can select the target spatial mode corresponding to the i-th coded data block from among K spatial modes and transmit the i-th coded data block. For instance, the first communication device can send a signal modulated or carrying the i-th coded data block to the RIS corresponding to the target spatial mode, and control the RIS to reflect the signal modulated or carrying the i-th coded data block according to the RIS beam direction corresponding to the target spatial mode.

[0106] For a second communication device that knows the target spatial pattern corresponding to the i-th coded data block, the receiving antenna can be aligned with the RIS beam direction corresponding to the target spatial pattern to receive the i-th coded data block. For example, it can receive signals modulated or carrying the i-th coded data block.

[0107] The transmission rate can be pre-configured, determined through negotiation between the first and second communication devices, or determined by the first communication device according to a set transmission mechanism (such as a congestion mechanism). This application does not limit the method by which the first communication device determines the transmission rate.

[0108] In one possible implementation, in order to improve the reliability and efficiency of data transmission, the first communication device can determine the transmission rate based on the channel quality of the target spatial pattern corresponding to the i-th coded data block; and based on the transmission rate, send the i-th coded data block to the second communication device through the target spatial pattern corresponding to the i-th coded data block.

[0109] Channel quality can include one or more of the following: channel parameters such as signal received power or signal-to-noise ratio (SNR), and channel capacity. Channel capacity is an important indicator of a channel's ability to transmit information; it represents the maximum average information rate when the channel transmits information without errors. The size of the channel capacity depends on the characteristics of the channel, including its bandwidth, SNR, and signal processing methods.

[0110] As an example, different channel quality intervals can be configured with different transmission rates. For instance, channel quality interval 1 can be configured with a transmission rate of 1, channel quality interval 2 with a transmission rate of 2, and so on, with channel quality interval X corresponding to a transmission rate X. After the first communication device obtains the channel quality of the target spatial mode, it can determine the transmission rate based on the channel quality interval in which the target spatial mode's channel quality falls, and the mapping relationship between different channel quality intervals and different transmission rates. For example, if the channel quality interval in which the target spatial mode's channel quality falls is channel quality interval 2, the transmission rate determined by the first communication device is transmission rate 2.

[0111] The channel quality of the target space mode can be determined by the first communication device based on the pilot signal (also called pilot or reference signal) received from the second communication device in the target space mode, or it can be determined by the second communication device after receiving the pilot signal from the first communication device in the target space mode and then sending it to the first communication device. This application does not limit the method by which the first communication device determines the channel quality of the target space mode.

[0112] S404: The second communication device decodes the N encoded data blocks according to the encoding matrix to obtain N data blocks.

[0113] Because the second communication device knows the target space pattern corresponding to each of the N coded data blocks, it can correctly receive each coded data block (e.g., demodulate each coded data block from the received signal). After receiving the N coded data blocks, it can decode them according to the coding matrix to obtain the original N data blocks. For example, by using M=A -1 X decodes the original N data blocks.

[0114] With the secure communication method of this application, for each coded data block (e.g., the i-th coded data block) sent by the first communication device, since the third-party user does not know which spatial mode the coded data is transmitted through, the third-party user can only randomly guess one from K spatial modes and align the antenna with the RIS beam direction of the corresponding spatial mode. Due to the existence of the coding matrix, the third-party user can only successfully decode at least one original data block if they correctly guess which spatial mode at least N-1 coded data blocks are transmitted through, and the link channel capacity is not less than the legal link channel capacity between the first and second communication devices. This greatly reduces the probability of information leakage.

[0115] Referring to Figure 5, which illustrates the relationship between the probability of information leakage and the number of spatial patterns, the horizontal axis in Figure 5 represents the number of spatial patterns (K), and the vertical axis represents the probability of information leakage (P). Figure 5 illustrates the probability of information leakage under different numbers of spatial patterns when the number of data blocks (N) is 15 and 20, respectively. As can be seen from Figure 5, as the number of spatial patterns increases, the probability of information leakage decreases rapidly, and the probability of a third-party user obtaining data blocks transmitted through the legitimate link between the first and second communication devices decreases rapidly.

[0116] Referring to Figure 6, which illustrates the relationship between the probability of information leakage and the number of data blocks, the horizontal axis represents the number of data blocks (N), and the vertical axis represents the probability of information leakage (P). Figure 6 illustrates the probability of information leakage under different numbers of data blocks when the number of spatial patterns (K) is 5 and 10, respectively. As can be seen from Figure 6, as the number of data blocks increases, the probability of information leakage decreases rapidly, and the probability of a third-party user obtaining data blocks transmitted through the legitimate link between the first and second communication devices decreases rapidly.

[0117] The communication device provided in the embodiments of this application is described below. Please refer to FIG7, which is a schematic structural diagram of the communication device in the embodiments of this application. The communication device may include units or modules corresponding to all or part of the steps in the above method embodiments, and can be used to execute the steps executed by the first communication device or the second communication device in the above embodiments. For details, please refer to the relevant descriptions in the above method embodiments.

[0118] As shown in Figure 7, the communication device 700 includes a processing unit 710 and an interface unit 720. The processing unit 710 can be a processor or a processing circuit, and the interface unit 720 can be a transceiver unit or an input / output interface. The communication device 700 can be used to implement the steps performed by the first communication device in the above embodiments.

[0119] When the communication device 700 is used to implement the steps performed by the first communication device in the above embodiments:

[0120] Processing unit 710 is used to encode N data blocks according to the encoding matrix to obtain N encoded data blocks, where N is an integer greater than or equal to 2; and for the i-th encoded data block among the N encoded data blocks, to determine the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes corresponding to RIS according to the spatial mode selection parameter corresponding to the i-th encoded data block, where i is 1, 2, ..., N, and K is an integer greater than or equal to 2; interface unit 720 is used to send the i-th encoded data block to the second communication device through the target spatial mode corresponding to the i-th encoded data block.

[0121] In one possible design, when the interface unit 720 sends the i-th coded data block to the second communication device through the target space mode corresponding to the i-th coded data block, it is specifically used to determine the transmission rate based on the channel quality of the target space mode corresponding to the i-th coded data block; and according to the transmission rate, send the i-th coded data block to the second communication device through the target space mode corresponding to the i-th coded data block.

[0122] In one possible design, the spatial mode selection parameters include a key. When the processing unit 710 determines the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th encoded data block, it is specifically used to determine the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes based on the key corresponding to the i-th encoded data block in the key stream, wherein the key stream is derived from the root key used for communication with the second communication device.

[0123] In one possible design, the spatial mode selection parameters include a spatial mode index. Before the processing unit 710 determines the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block, the interface unit 720 is also used to send pilot signals to the second communication device through the K spatial modes respectively; and to receive the spatial mode index from the second communication device. The spatial mode index is determined based on the channel parameters of the second communication device receiving pilot signals through the K spatial modes respectively. The spatial mode index is used to identify the target spatial mode corresponding to the i-th coded data block.

[0124] In one possible design, the interface unit 720 is further configured to receive channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index from the second communication device, wherein the channel parameters and / or channel capacity are used to determine the channel quality of the spatial mode corresponding to the spatial mode index.

[0125] In one possible design, the spatial mode selection parameters include channel parameters. When the processing unit 710 determines the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block, it is specifically used to determine the channel parameters corresponding to the K spatial modes respectively; and to determine the target spatial mode corresponding to the i-th coded data block from among the K spatial modes based on the channel parameters corresponding to the K spatial modes respectively.

[0126] In one possible design, the encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

[0127] In one possible design, K is determined based on the number of RIS R and the number of available spatial beam directions D for each RIS configuration.

[0128] When the communication device 700 is used to implement the steps performed by the second communication device in the above embodiments:

[0129] Processing unit 710 is used to determine the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes corresponding to RIS, based on the spatial mode selection parameters corresponding to the i-th encoded data block. Here, i is 1, 2, ..., N, and N and K are integers greater than or equal to 2. Interface unit 720 is used to receive the i-th encoded data block from the first communication device through the target spatial mode corresponding to the i-th encoded data block. Processing unit 710 is also used to decode the N encoded data blocks according to the encoding matrix to obtain N data blocks.

[0130] In one possible design, when the interface unit 720 receives the i-th coded data block from the first communication device through the target space mode corresponding to the i-th coded data block, it is specifically used to align the receiving antenna with the RIS beam direction corresponding to the target space mode to receive the i-th coded data block from the first communication device.

[0131] In one possible design, the spatial mode selection parameters include a key. When the processing unit 710 determines the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th encoded data block, it is specifically used to determine the target spatial mode corresponding to the i-th encoded data block from among the K spatial modes based on the key corresponding to the i-th encoded data block in the key stream, wherein the key stream is derived from the root key used for communication with the first communication device.

[0132] In one possible design, the spatial mode selection parameters include a spatial mode index. The interface unit 720 is also used to receive pilot signals from the first communication device through K spatial modes respectively. The processing unit 710 is also used to determine the spatial mode index according to the channel parameters of the pilot signals received through the K spatial modes respectively. The spatial mode index is used to identify the target spatial mode corresponding to the i-th coded data block. The interface unit 720 is also used to send the spatial mode index to the first communication device.

[0133] In one possible design, the interface unit 720 is also used to send the channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index to the first communication device.

[0134] In one possible design, the spatial mode selection parameters include channel parameters. When the processing unit 710 determines the target spatial mode corresponding to the i-th coded data block from among the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block, it is specifically used to determine the channel parameters corresponding to the K spatial modes respectively; and to determine the target spatial mode corresponding to the i-th coded data block from among the K spatial modes based on the channel parameters corresponding to the K spatial modes respectively.

[0135] In one possible design, the encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

[0136] In one possible design, K is determined based on the number of RIS R and the number of available spatial beam directions D for each RIS configuration.

[0137] As shown in Figure 8, this application also provides a communication device 800, including a processor 810 and potentially a communication interface 820. The processor 810 and the communication interface 820 are coupled to each other. It is understood that the communication interface 820 can be a transceiver, input / output interface, input interface, output interface, interface circuit, etc. Optionally, the communication device 800 may further include a memory 830 for storing instructions executed by the processor 810, or storing input data required by the processor 810 to execute instructions, or storing data generated after the processor 810 executes instructions. The memory 830 can be a physically independent unit, or it can be coupled to the processor 810, or the processor 810 may include the memory 830.

[0138] When the communication device 800 is used to implement the steps performed by the first communication device or the second communication device in the above embodiments, the processor 810 can be used to implement the function of the processing unit 710, and the communication interface 820 can be used to implement the function of the interface unit 720.

[0139] In this application embodiment, the processor (e.g., processor 810) can be one or more central processing units (CPUs). If the processor is a CPU, it can be a single-core CPU or a multi-core CPU. The processor can also be one or a combination of several of the following: CPU, general-purpose processor, application-specific integrated circuit (ASIC), digital signal processor (DSP), microprocessor unit (MPU), microcontroller unit (MCU), graphics processing unit (GPU), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, artificial intelligence processor (AI processor), or neural processing unit (NPU). The processor can implement or execute the methods, steps, and logic block diagrams disclosed in this application embodiment. The steps of the methods disclosed in this application embodiment can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0140] In this embodiment, the memory (e.g., memory 830) may include, but is not limited to, cache, read-only memory (ROM), random access memory (RAM), synchronous dynamic random access memory (SDRAM), hard disk drive (HDD) or solid-state drive (SSD), erasable programmable read-only memory (EPROM), or compact disc read-only memory (CD-ROM), etc. Memory is any other medium capable of carrying or storing desired program code having an instruction or data structure form and accessible by a computer, but is not limited thereto. The memory in this embodiment may also be a circuit or any other device capable of implementing storage functions for storing computer programs or instructions, and / or data.

[0141] It is understood that the method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network device or a terminal device. Alternatively, the processor and storage medium can exist as discrete components in the network device or terminal device.

[0142] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one network device, terminal, computer, server, or data center to another network device, terminal, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0143] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0144] In the embodiments of this application, the term "exemplary" is used to indicate that it is an example, illustration, or description. Any embodiment or design that is described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of the term "exemplary" is intended to present the concept in a specific manner.

[0145] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A secure communication method, characterized in that, include: Based on the encoding matrix, N data blocks are encoded to obtain N encoded data blocks, where N is an integer greater than or equal to 2; For the i-th coded data block among the N coded data blocks, the target spatial mode corresponding to the i-th coded data block is determined from the K spatial modes corresponding to the reconfigurable smart surface RIS according to the spatial mode selection parameters corresponding to the i-th coded data block, where i is 1, 2, ..., N in sequence, and K is an integer greater than or equal to 2. The i-th encoded data block is sent to the second communication device using the target space pattern corresponding to the i-th encoded data block.

2. The method as described in claim 1, characterized in that, The step of sending the i-th encoded data block to the second communication device through the target space pattern corresponding to the i-th encoded data block includes: The transmission rate is determined based on the channel quality of the target spatial mode corresponding to the i-th coded data block; According to the transmission rate, the i-th coded data block is transmitted to the second communication device through the target space mode corresponding to the i-th coded data block.

3. The method as described in claim 1 or 2, characterized in that, The spatial mode selection parameters include a key. The step of determining the target spatial mode corresponding to the i-th encoded data block from the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th encoded data block includes: Based on the key corresponding to the i-th encoded data block in the key stream, the target spatial mode corresponding to the i-th encoded data block is determined among the K spatial modes, wherein the key stream is derived based on the root key used for communication with the second communication device.

4. The method as described in claim 1 or 2, characterized in that, The spatial mode selection parameter includes a spatial mode index. Before determining the target spatial mode corresponding to the i-th encoded data block from the K spatial modes corresponding to RIS based on the spatial mode selection parameter corresponding to the i-th encoded data block, the method further includes: Pilot signals are sent to the second communication device through the K spatial patterns respectively; The spatial pattern index is received from the second communication device. The spatial pattern index is determined based on the channel parameters of the pilot signals received by the second communication device through the K spatial patterns respectively. The spatial pattern index is used to identify the target spatial pattern corresponding to the i-th coded data block.

5. The method as described in claim 4, characterized in that, The method further includes: The system receives channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index from the second communication device, wherein the channel parameters and / or channel capacity are used to determine the channel quality of the spatial mode corresponding to the spatial mode index.

6. The method as described in claim 1, characterized in that, The spatial mode selection parameters include channel parameters. The step of determining the target spatial mode corresponding to the i-th coded data block from the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block includes: Determine the channel parameters corresponding to the K spatial patterns respectively; Based on the channel parameters corresponding to the K spatial modes, the target spatial mode corresponding to the i-th coded data block is determined from the K spatial modes.

7. The method according to any one of claims 1-6, characterized in that, The encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

8. The method according to any one of claims 1-7, characterized in that, The K is determined based on the number R of the RIS and the number D of available spatial beam directions configured for each RIS.

9. A secure communication method, characterized in that, include: For the i-th coded data block among N coded data blocks, the target spatial mode corresponding to the i-th coded data block is determined from the K spatial modes corresponding to the reconfigurable smart surface RIS according to the spatial mode selection parameters corresponding to the i-th coded data block, where i is 1, 2, ..., N, and N and K are integers greater than or equal to 2. The i-th encoded data block is received from the first communication device through the target space pattern corresponding to the i-th encoded data block; Based on the encoding matrix, the N encoded data blocks are decoded to obtain N data blocks.

10. The method as described in claim 9, characterized in that, Receiving the i-th encoded data block from the first communication device through the target space pattern corresponding to the i-th encoded data block includes: The receiving antenna is aligned with the RIS beam direction corresponding to the target spatial pattern to receive the i-th coded data block from the first communication device.

11. The method as described in claim 9 or 10, characterized in that, The spatial mode selection parameters include a key. The step of determining the target spatial mode corresponding to the i-th encoded data block from the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th encoded data block includes: Based on the key corresponding to the i-th encoded data block in the key stream, the target spatial mode corresponding to the i-th encoded data block is determined among the K spatial modes, wherein the key stream is derived based on the root key used for communication with the first communication device.

12. The method as described in claim 9 or 10, characterized in that, The spatial pattern selection parameters include a spatial pattern index, and the method further includes: Pilot signals from the first communication device are received through the K spatial modes respectively; Based on the channel parameters of the pilot signals received according to the K spatial modes, the spatial mode index is determined, and the spatial mode index is used to identify the target spatial mode corresponding to the i-th coded data block; The spatial pattern index is sent to the first communication device.

13. The method as described in claim 12, characterized in that, The method further includes: Send the channel parameters and / or channel capacity of the spatial mode corresponding to the spatial mode index to the first communication device.

14. The method as described in claim 9 or 10, characterized in that, The spatial mode selection parameters include channel parameters. The step of determining the target spatial mode corresponding to the i-th coded data block from the K spatial modes corresponding to RIS based on the spatial mode selection parameters corresponding to the i-th coded data block includes: Determine the channel parameters corresponding to the K spatial patterns respectively; Based on the channel parameters corresponding to the K spatial modes, the target spatial mode corresponding to the i-th coded data block is determined from the K spatial modes.

15. The method according to any one of claims 9-14, characterized in that, The encoding matrix is ​​an N*N matrix, and the vector group consisting of any N-2 row vectors and any 1 unit vector of the encoding matrix is ​​linearly independent.

16. The method according to any one of claims 9-15, characterized in that, The K is determined based on the number R of the RIS and the number D of available spatial beam directions configured for each RIS.

17. A communication device, characterized in that, It includes modules or units for performing the method as described in any one of claims 1-8; or, it includes modules or units for performing the method as described in any one of claims 9-16.

18. A communication device, characterized in that, It includes a processor and an interface circuit, the interface circuit being used to input and / or output signals, and the processor being used to implement the method as described in any one of claims 1-8 through logic circuits or execution instructions; or, to implement the method as described in any one of claims 9-16.

19. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a processor, cause the method as described in any one of claims 1-8 to be implemented; or cause the method as described in any one of claims 9-16 to be implemented.

20. A chip system, characterized in that, The chip system includes a processor for coupling with a memory for storing computer programs or instructions that, when executed by the processor, implement the method as described in any one of claims 1-8; or, implement the method as described in any one of claims 9-16.

21. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions that, when executed by a processor, cause the method as described in any one of claims 1-8 to be implemented; or cause the method as described in any one of claims 9-16 to be implemented.

22. A communication system, characterized in that, The communication system includes a first communication device and a second communication device; The first communication device is configured to perform the method as described in any one of claims 1-8; The second communication device is used to perform the method as described in any one of claims 9-16.

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