Signal transmission method and device

Abstract

The present application provides a signal transmission method and device. In the method, K communication signal streams are mapped into N communication signal streams by means of an encryption function, thereby implementing encryption of physical layer communication signals with low implementation complexity. The K first communication signal streams can be independent signal streams and can be used for carrying information, that is, information can be transmitted by means of communication signals, so that the communication process of a communication link will not be changed, thereby reducing the impact on communication services; moreover, when users conduct communication, unauthorized users cannot obtain the initial K communication signals, thereby protecting perception privacy of a target in a scenario where users conduct communication services, improving the effect of protecting perception privacy.

Description

Signal transmission method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 26, 2023, with application number 202311819196.2 and application name “Method and Device for Transmitting Signals”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0003] Perception uses wireless signals to measure channels and infer information related to the environment or perceived objects (for example, people or objects in the environment) based on the measurement results. However, the measurement signals used for perception have a public signal structure and may be eavesdropped by attackers, resulting in the leakage of perception privacy.

[0004] Existing technologies for protecting perceptual privacy primarily consider scenarios where attackers exploit measurement signals exposed by communication links to obtain information about a target while users are performing perceptual services. Therefore, existing technologies aim to prevent attackers from exploiting perceptual signals to gain access to perceptual privacy. However, these scenarios are limited and their effectiveness in protecting perceptual privacy is limited. Summary of the Invention

[0005] The embodiments of the present application provide a method and apparatus for transmitting signals, which can prevent attackers from using communication signals of a communication link to obtain perceived privacy, thereby improving the protection effect of perceived privacy.

[0006] In a first aspect, a method for transmitting a signal is provided. The method can be performed by a first communication device, which can be a terminal, a device including a terminal, or a chip or logic module within the terminal. Alternatively, the first communication device can also be a network device, a device including a network device, or a chip or logic module within the network device. For ease of description, the following description takes the method of the first aspect performed by the first communication device as an example. The method includes: obtaining K first communication signal streams; mapping the K first communication signal streams into N communication signal streams according to a first encryption function to obtain a mapped signal, the N communication signal streams corresponding to N antenna ports and / or the N communication signal streams corresponding to N layers, K and N being positive integers, and K being less than N; and transmitting the mapped signal.

[0007] Based on the method of the first aspect, it can be seen that K communication signal streams are mapped into N communication signal streams through an encryption function, thereby achieving encryption of the physical layer communication signal, with low implementation complexity. The K first communication signal streams can be independent signal streams that can be used to carry information, that is, information can be transmitted through communication signals without changing the communication process of the communication link, thereby reducing the impact on communication services. Moreover, when a user is communicating, even if an unauthorized user may obtain N communication signal streams, they cannot obtain the initial K communication signals. This can protect the target's perceived privacy in scenarios where the user is conducting communication services, thereby improving the protection of perceived privacy.

[0008] In one possible implementation, a first linear mapping transformation is performed on the K first communication signal streams according to the first encryption function to obtain N mapped communication signal streams. The first linear mapping transformation includes:

[0009] in, is the first encryption function, x1,x2,...,x K are K first communication signal streams, t i is the current time or the sampling time of the first encryption function, x′1, x′2,…, x′ N There are N communication signal flows.

[0010] It can be understood that encryption of the K first communication signal streams is achieved by linearly combining them. The coefficients of the linear combination can be the time-sampled values ​​of the first encryption function, where the first encryption function is encrypted and shared by the sending node and the receiving node, and the receiving node can demodulate the K first communication signal streams based on the first encryption function. This linear mapping transformation encryption method does not require the participation of additional equipment and has low implementation complexity. It can protect the target's perceived privacy in scenarios where users are conducting communication services, thereby improving the protection of perceived privacy.

[0011] In one possible implementation, the first encryption function may include a second encryption function and a power allocation factor for each of the K first communication signal streams. Based on the second encryption function and the power allocation factor, the K first communication signal streams are mapped into N communication signal streams to obtain mapped signals.

[0012] It can be seen that the power allocation factor of each communication signal flow represents the power allocation requirement of each communication signal flow. The power allocation requirement can be determined according to the communication service requirement. The first encryption function can be composed of the second encryption function and the power allocation factor. That is to say, the first encryption function can be determined by the communication service requirement of the communication link, which reduces the impact on the communication performance while encrypting the communication signal.

[0013] Optionally, the N communication signal streams may include K second communication signal streams and NK third communication signal streams, wherein the K second communication signal streams are obtained by mapping the K first communication signal streams according to a power allocation factor, and the NK third communication signal streams are obtained by mapping the K first communication signal streams according to a second encryption function. It can be understood that using the power allocation factor to map the K first communication signal streams meets the communication service requirements, and using the NK communication signal streams for privacy protection provides a feasible solution for encrypted mapping of communication signal streams.

[0014] Among them, according to the second encryption function, a second linear mapping transformation is performed on K1 first communication signal streams in the K first communication signal streams, and according to the first coefficient, a second linear mapping transformation is performed on K-K1 first communication signal streams other than the K1 first communication signal streams in the K first communication signal streams, and a second linear mapping transformation is performed on the K first communication signal streams according to the power allocation factor to obtain N mapped communication signal streams, and the second linear mapping transformation includes:

[0015] Among them, α 1,1 (t i ),α 1,2 (t i ),…,α N-K,K1 (t i ) is the second encryption function, β 1,K1+1 ,β 1,K1+2 ,…,β N-K,K is the first coefficient, P1(t i ),P2(t i ),...,P K (t i ) is the power allocation factor of each communication signal flow in the K first communication signal flows, x1, x2, ..., x K are K first communication signal streams, t i is the current time or the sampling time of the second encryption function, x′1, x′2, ..., x′ N There are N communication signal flows.

[0016] It is understood that a portion of the K first communication signal streams can be encrypted using the second encryption function, namely K1 first communication signal streams. The remaining K-K1 first communication signal streams can be linearly mapped and transformed according to the first coefficient, where the first coefficient can have any value, thereby increasing the flexibility of signal stream encryption. By linearly combining the K first communication signal streams using the second encryption function and the power allocation factor, power allocation requirements are met while also encrypting the communication signal streams, thereby improving the protection of perceived privacy.

[0017] In one possible implementation, transmitting the mapped signal may include: transmitting K second communication signal streams and NK third communication signal streams; wherein the singular value corresponding to the channel for transmitting the K second communication signal streams is greater than the singular value corresponding to the channel for transmitting the NK third communication signal streams, and the singular value is obtained by performing singular value decomposition of the channel matrix.

[0018] It can be understood that before transmitting the communication signal, the channel matrix is ​​subjected to singular value decomposition to obtain multiple singular values, and K independent communication signal streams are transmitted on the channels corresponding to the larger singular values ​​among the multiple singular values ​​(for example, the channels corresponding to the first K largest singular values), and privacy protection is achieved using the channels corresponding to the smaller singular values ​​(for example, the channels corresponding to the singular values ​​other than the first K largest singular values). In this way, the rate loss of the transmitted signal is small and the impact on the communication performance is low.

[0019] In one possible implementation, the signal transmission method may further include: obtaining K pilot symbols before transmitting the K second communication signal streams and the NK third communication signal streams; mapping the K pilot symbols into N pilot symbols according to a third encryption function to obtain mapped pilot symbols, wherein the mapped pilot symbols are used for channel estimation; transmitting the mapped pilot symbols, and receiving a channel matrix obtained by the channel estimation.

[0020] It can be understood that before the sender and receiver communicate, channel estimation is performed based on the pilot symbols. The encryption mapping method for the pilot symbols based on the third encryption function can refer to the encryption mapping method for the K first communication signals. The third encryption function is encrypted and shared by the sending node and the receiving node, and the receiving node performs channel estimation based on the third encryption function and the K pilot symbols. In this way, sending the mapped pilot symbols during the channel estimation phase can prevent unauthorized users from perceiving the pilot symbols through monitoring, thereby enhancing the protection of user perception privacy.

[0021] Among them, the third encryption function can be the same as the first encryption function, that is, the first encryption function is reused to reduce the implementation complexity. The third encryption function can also be different from the first encryption function, that is, it is decoupled from the implementation of the above-mentioned first encryption function, and the implementation method can be more flexible.

[0022] Optionally, the first encryption function can be a time-varying function with a low-pass characteristic, that is, the spectrum of the first encryption function has at least one low-frequency component, and the frequency of this low-frequency component is close to the frequency characteristics of the perceived target, wherein the frequency characteristics of the perceived target can be frequency characteristics of the perceived target with periodic motion characteristics, such as heart rate, breathing frequency, walking frequency, etc. For example, in the scenario of perceiving the target's breathing frequency, the frequency of the low-frequency component of the spectrum of the first encryption function should be close to the target's breathing frequency. In this way, when the communication signal is encrypted, the target's frequency characteristics are masked in the power spectrum of the signal received by unauthorized users, thereby protecting the target's perceived privacy.

[0023] Optionally, the third encryption function may be a time-varying function with a low-pass characteristic, and may refer to the first encryption function.

[0024] In one possible implementation, a first sampled value of a first encryption function is used in mapping K first communication signal streams into N communication signal streams. The first sampled value is obtained by sampling the first encryption function at a first moment. A second sampled value of a third encryption function is used in mapping K pilot symbols into N pilot symbols. The second sampled value is obtained by sampling the third encryption function at a second moment. When the first and third encryption functions are the same, the interval between the first and second moments is within a preset time period, and the first and second sampled values ​​are the same during the preset time period.

[0025] It can be understood that if the first and third encryption functions are the same, the sampled values ​​of the encryption functions used in the channel estimation and communication stages are the same. This allows the channel estimation stage to only estimate the equivalent channel, and the communication stage to achieve demodulation using the equivalent channel and the third encryption function, thereby reducing communication overhead. Reference can be made to the method of the second aspect. This ensures that the receiving node can correctly demodulate, achieving communication performance while also protecting user-perceived privacy.

[0026] In a second aspect, a method for transmitting a signal is provided, which can be performed by a second communication device, which can be a terminal, a device including a terminal, or a chip or logic module in the terminal. Alternatively, the second communication device can also be a network device, a device including a network device, or a chip or logic module in the network device. For the convenience of expression, the following description takes the method of the second aspect performed by the second communication device as an example. The method may include: obtaining a mapped signal, the mapped signal including N communication signal streams, the N communication signal streams being obtained based on K first communication signal streams and a first encryption function, the N communication signal streams corresponding to N antenna ports of the sending node and / or the N communication signal streams corresponding to N layers. Demodulate the mapped signal according to the first encryption function to obtain K first communication signal streams.

[0027] In one possible implementation, the N communication signal streams are obtained by performing a first linear mapping transformation on the K first communication signal streams based on the first encryption function. The first linear mapping transformation includes:

[0028] in, is the first encryption function, x1,x2,...,x K are K first communication signal streams, t i is the current time or the sampling time of the first encryption function, x′1, x′2, ..., x′ N There are N communication signal flows.

[0029] In one possible implementation, the first encryption function may include a second encryption function and a power allocation factor of each communication signal stream in the K first communication signal streams, and the N communication signal streams are obtained based on the mapping of the K first communication signal streams, the second encryption function and the power allocation factor.

[0030] Optionally, the N communication signal streams include K second communication signal streams and NK third communication signal streams, wherein the K second communication signal streams are obtained by mapping the K first communication signal streams according to the power allocation factor, and the NK third communication signal streams are obtained by mapping the K first communication signal streams according to the second encryption function.

[0031] The N communication signal streams are obtained by performing a second linear mapping transformation on K1 first communication signal streams among the K first communication signal streams based on a second encryption function, performing a second linear mapping transformation on K-K1 first communication signal streams among the K first communication signal streams except the K1 first communication signal streams by the first coefficient, and performing a second linear mapping transformation on the K first communication signal streams based on a power allocation factor. The second linear mapping transformation includes:

[0032] Among them, α 1,1 (t i ),α 1,2 (t i ),...,α N-K,K1 (t i ) is the second encryption function, β 1,K1+1 ,β 1,K1+2 ,...,β N-K,K is the first coefficient, P1(t i ),P2(t i ),...,P K (t i ) is the power allocation factor of each communication signal flow in the K first communication signal flows, x1, x2, ..., x Kare K first communication signal streams, t i is the current time or the sampling time of the second encryption function, x′1, x′2, ..., x′ N There are N communication signal flows.

[0033] Optionally, K first communication signal streams are obtained according to the first encryption function and the signal after channel demodulation mapping.

[0034] In one possible implementation, the signal transmission method may further include: before demodulating the mapped signal according to the first encryption function and the channel to obtain K first communication signal streams, obtaining mapped pilot symbols, the mapped pilot symbols being obtained based on mapping the K pilot symbols and a third encryption function. Channel estimation is performed based on the mapped pilot symbols and the third encryption function to obtain a channel.

[0035] Optionally, the first encryption function and the third encryption function are the same, or the first encryption function and the third encryption function are different.

[0036] In one possible implementation, a first sampled value of a first encryption function is used in mapping K first communication signal streams into N communication signal streams. The first sampled value is obtained by sampling the first encryption function at a first moment. A second sampled value of a third encryption function is used in mapping K pilot symbols into N pilot symbols. The second sampled value is obtained by sampling the third encryption function at a second moment. When the first and third encryption functions are the same, the interval between the first and second moments is within a preset time period, and the first and second sampled values ​​are the same during the preset time period.

[0037] In one possible implementation, the signal transmission method may further include: when the first encryption function and the third encryption function are the same, performing channel estimation based on the mapped pilot symbol and the third encryption function to obtain an equivalent channel, and the equivalent channel has a corresponding relationship with the channel. Demodulating the mapped signal according to the first encryption function and the equivalent channel to obtain K first communication signal streams. It can be understood that if the first encryption function and the third encryption function are the same, then when performing channel estimation, only the equivalent channel needs to be estimated, and the corresponding relationship between the equivalent channel and the channel can be a linear mapping relationship, and the channel can be calculated based on the third encryption function and the equivalent channel. In the communication stage, demodulation can be achieved through the equivalent channel and the third encryption function, thereby reducing the overhead during the communication process.

[0038] Optionally, the third encryption function is encrypted and shared by the sending node and the receiving node.

[0039] Optionally, the third encryption function is a time-varying function with a low-pass characteristic.

[0040] It can be understood that the relevant technical effects of the method of the second aspect mentioned above can also refer to the relevant introduction of the first aspect mentioned above, and will not be repeated here.

[0041] In a third aspect, a communication device is provided. The communication device includes: a module for executing the method described in any one of aspects 1 to 2, such as a transceiver module and a processing module. For example, the transceiver module is configured to indicate the transceiver function of the communication device, and the processing module is configured to perform functions of the communication device other than the transceiver function.

[0042] Optionally, the transceiver module may include a sending module and a receiving module, wherein the sending module is used to implement the sending function of the communication device described in the third aspect, and the receiving module is used to implement the receiving function of the communication device described in the third aspect.

[0043] Optionally, the communication device described in the third aspect may further include a storage module, wherein the storage module stores a program or instruction. When the processing module executes the program or instruction, the communication device may execute the method described in any one of the first aspect to the second aspect.

[0044] It can be understood that the communication device described in the third aspect can be a terminal or a network device, or a chip (system) or other parts or components that can be set in a terminal or a network device, or a device that includes a terminal or a network device. This application does not limit this.

[0045] In addition, the technical effects of the communication device described in the third aspect can refer to the technical effects of the first aspect mentioned above, and will not be repeated here.

[0046] In a fourth aspect, a communication device is provided, comprising: a processor configured to execute the method described in any one of the first to second aspects.

[0047] In one possible implementation, the communication device described in the fourth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the fourth aspect to communicate with other communication devices.

[0048] In one possible implementation, the communication device described in the fourth aspect may further include a memory. The memory may be integrated with the processor or provided separately. The memory may be used to store the computer program and / or data involved in the method described in any one of the first and second aspects.

[0049] In an embodiment of the present application, the communication device described in the fourth aspect can be the terminal or network device described in any one of the first to second aspects, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0050] In addition, the technical effects of the communication device described in the fourth aspect can refer to the technical effects of the methods described in any one of the first aspect to the second aspect, and will not be repeated here.

[0051] In a fifth aspect, a communication device is provided, comprising: a processor coupled to a memory, the processor configured to execute a computer program or instruction stored in the memory, so that the communication device performs the method described in any one of the first to second aspects.

[0052] In one possible implementation, the communication device may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device to communicate with other communication devices.

[0053] In a possible implementation, the communication device further includes the memory for storing the above-mentioned computer program or instruction. Optionally, the memory and the processor are integrated together.

[0054] In an embodiment of the present application, the communication device described in the fifth aspect can be the terminal or network device described in any one of the first to second aspects, or a chip (system) or other parts or components that can be set in the terminal or network device, or a device that includes the terminal or network device.

[0055] In addition, the technical effects of the communication device described in the fifth aspect can refer to the technical effects of the methods described in any one of the first aspect to the second aspect, and will not be repeated here.

[0056] In a sixth aspect, a communication system is provided, comprising: a first communication device for executing the method described in the first aspect, and a second communication device for executing the method described in the second aspect.

[0057] In a seventh aspect, a computer-readable storage medium is provided, comprising: a computer program or instructions; when the computer program or instructions are executed on a computer, the method described in any one of the first to second aspects above is implemented.

[0058] In an eighth aspect, a computer program product is provided, comprising a computer program or instructions, which, when executed on a computer, enables the method described in any one of the first to second aspects to be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG1 is a schematic diagram of the architecture of a communication system according to an embodiment of the present application;

[0060] FIG2 is a second schematic diagram of the architecture of the communication system provided in an embodiment of the present application;

[0061] FIG3 is a schematic diagram of an application scenario provided in an embodiment of the present application;

[0062] FIG4 is a schematic diagram of a signal transmission process according to an embodiment of the present application;

[0063] FIG5 is a schematic structural diagram of a wireless communication system provided in an embodiment of the present application;

[0064] FIG6 is a second schematic diagram of an application scenario provided by an embodiment of the present application;

[0065] FIG7 is a third schematic diagram of an application scenario provided by an embodiment of the present application;

[0066] FIG8 is a first structural diagram of a communication device provided in an embodiment of the present application;

[0067] FIG9 is a second structural diagram of the communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] Perception is a key application in mobile communication systems evolving beyond the fifth generation (5G), such as the sixth generation (6G), and next-generation Wireless Fidelity (Wi-Fi) systems. The basic principle of perception is to use wireless signals to measure the channel, obtain channel state information (CSI) or channel impulse response (CIR) from the measurement results, and infer information about the environment or the perceived object (such as people or objects in the environment) from the CSI or CIR.

[0069] Wireless systems can perform sensing through special "measurement" signals, such as pilot signals. However, these signals have a public signal structure. By measuring these measurement signals, attackers can potentially perceive the physical environment and infer user location, trajectory, and behavioral characteristics, potentially exposing privacy. The attackers in this case can be unauthorized users. Therefore, mechanisms are needed to prevent unauthorized users from inferring sensitive information based on sensing measurement data, thereby protecting the privacy of authorized users.

[0070] Existing perception privacy protection technologies all consider scenarios where attackers exploit the public measurement signals (such as pilot signals) of the communication link to obtain the target's privacy while the user is performing perception services. For this scenario, encryption algorithms, signal processing, protocol design, and other methods are usually used to prevent unauthorized users from obtaining correct channel state information through channel estimation. Consequently, they are unable to obtain information related to the environment or the perceived object through wireless perception algorithms, such as whether the perception object exists in the environment, the perception object's motion trajectory, breathing rate, heart rate, and other information, in order to protect user privacy. The goal of existing perception privacy protection technologies is to prevent unauthorized users from performing perception services while legitimate users are performing perception services, that is, to prevent unauthorized users from using perception signals to obtain perception privacy.

[0071] However, while a user is engaging in communication services, even though an attacker may not be interested in the user's communication data, they can still exploit the communication signals along the communication link for perception, thereby inferring environmental characteristics and obtaining the target's perceived privacy. In other words, an attacker can still exploit the communication signals along the communication link to obtain perceived privacy. Therefore, considering only the scenario where the user is engaging in perception services only prevents attackers from exploiting perception signals to obtain perceived privacy. This scenario is limited and cannot effectively protect perceived privacy when both parties on the communication link are engaging in communication services.

[0072] In response to the above technical problems, the embodiments of the present application propose the following technical solutions.

[0073] The technical solution in this application will be described below with reference to the accompanying drawings.

[0074] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as wireless network (Wi-Fi) systems, vehicle to everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, fourth generation (4G) mobile communication systems, such as long term evolution (LTE) systems, 5G, such as new radio (NR) systems, and communication systems evolved after 5G such as 6G.

[0075] In the embodiment of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the first indication information, the second indication information, or the third indication information below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, where there is an association between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

[0076] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. As can be seen from the above, for example, when it is necessary to indicate multiple pieces of information of the same type, different indication methods may be used for different pieces of information. During the specific implementation process, the desired indication method can be selected according to specific needs. The embodiments of the present application do not limit the selected indication method. As such, the indication methods involved in the embodiments of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0077] It should be understood that the information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in the embodiments of this application. Among them, the sending period and / or sending time of these sub-information can be predefined, for example, predefined according to a protocol, or can be configured by the sending node device by sending configuration information to the receiving node device.

[0078] "Pre-definition" or "pre-configuration" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in the device, and the embodiments of the present application do not limit the specific implementation method. Among them, "saving" can mean saving in one or more memories. The one or more memories can be set separately or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories can also be partially set separately and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, and the embodiments of the present application do not limit this.

[0079] The "protocol" involved in the embodiments of the present application may refer to a protocol family in the communication field, a standard protocol with a similar protocol family frame structure, or a related protocol used in future communication systems. The embodiments of the present application do not make specific limitations on this.

[0080] In the embodiments of the present application, descriptions such as "when...", "in the case of...", "if" and "if" all mean that the device will perform corresponding processing under certain objective circumstances. It does not limit the time, nor does it require the device to perform judgment actions when implemented, nor does it mean that there are other limitations.

[0081] In the description of the embodiments of the present application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship. For example, A / B can represent A or B. "And / or" in the embodiments of the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, in the description of the embodiments of the present application, unless otherwise specified, "multiple" refers to two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with basically the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. At the same time, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or implementation described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or implementations. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0082] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0083] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail using the communication system shown in Figure 1 as an example. For example, Figure 1 is a schematic diagram of the architecture of a communication system applicable to the method provided in the embodiments of the present application.

[0084] The communication system may include: a first communication device and a second communication device. The first communication device may serve as a sending node of a legitimate communication link in the embodiment of the present application, and the second communication device may serve as a receiver of the legitimate communication link in the embodiment of the present application.

[0085] The communication device can be a terminal or a network device, such as the first communication device terminal is a terminal and the second communication device is a network device, or the first communication device terminal is a network device and the second communication device is a terminal. Of course, communication between terminals or between network devices can also be carried out.

[0086] In a specific example, as shown in FIG1 , the communication system mainly includes at least one of the following: a terminal, and a network device, such as an access network device.

[0087] For example, a possible, non-limiting architecture of the communication system can be shown in FIG2 . As shown in FIG2 , the communication system 10 includes a radio access network (RAN) 100, a core network (CN) 200, and the Internet 300. RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG2 , collectively referred to as 110) and at least one terminal (e.g., 120a-120j in FIG2 , collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in FIG2 ). Terminal 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wiredly connected to core network 200. The core network devices in core network 200 and RAN node 110 in RAN 100 can be separate physical devices, or they can be the same physical device that integrates core network logical functions and radio access network logical functions.

[0088] The RAN 100 may be a 3GPP-related cellular system, such as a 4G or 5G mobile communication system, or a future-oriented evolutionary system (such as a 6G mobile communication system). The RAN 100 may also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a Wi-Fi system. The RAN 100 may also be a communication system that integrates two or more of the above systems.

[0089] RAN node 110, sometimes also referred to as access network equipment, RAN entity, or access node, constitutes part of the communication system and facilitates wireless access for terminals. Multiple RAN nodes 110 in the communication system 10 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal 120 are relative. For example, network element 120i in Figure 2 can be a helicopter or drone, which can be configured as a mobile base station. For terminal 120j accessing the RAN 100 via network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal. RAN node 110 and terminal 120 are sometimes referred to as communication devices. For example, network elements 110a and 110b in Figure 2 can be understood as communication devices with base station functionality, and network elements 120a-120j can be understood as communication devices with terminal functionality.

[0090] In one possible scenario, a RAN node may be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB), a next generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access point (AP) in a Wi-Fi system. A RAN node may be a macro base station (such as 110a in FIG2 ), a micro base station or an indoor station (such as 110b in FIG2 ), a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, a RAN node may also be a server, a wearable device, a vehicle or an onboard device. For example, an access network device in vehicle to everything (V2X) technology may be a road side unit (RSU). All or part of the functions of a RAN node in this application may also be implemented by software functions running on hardware, or by virtualized functions instantiated on a platform (such as a cloud platform). A RAN node in this application may also be a logical node, a logical module, or software that can implement all or part of the functions of a RAN node.

[0091] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes respectively implement part of the functions of the base station. For example, the RAN node can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0092] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0093] It is understood that the above-mentioned RAN node can be a newly defined name, and RAN node can also be expressed in different ways, such as access node, network device, wireless access node, etc., without limitation. Unless otherwise specified in this application, network device is used to express it.

[0094] Terminals can also be referred to as terminal devices, user equipment (UE), mobile stations, or mobile terminals. They can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), smart point-of-sale (POS), customer-premises equipment (CPE), virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables (such as smart watches, smart bracelets, pedometers, and smart glasses), smart transportation, and smart cities. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicle devices (such as complete vehicle devices, vehicle-mounted modules, vehicle-mounted chips, on-board units (OBUs), or telematics boxes (T-BOXs)), drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, and satellite terminals. The embodiments of the present application do not limit the device form of the terminal.

[0095] Figure 3 is a schematic diagram of an application scenario of a communication system according to an embodiment of the present application. As shown in Figure 3, the communication system may include a sending node (i.e., a first communication device) and a receiving node (i.e., a second communication device) of a legal communication link. Based on the above communication system, the sending node and the receiving node may be a base station, an AP, a user terminal, or other equipment with wireless radio frequency signal transceiver capabilities. Since the sending node needs to send multiple communication signal streams (greater than or equal to 2), the encryption of the communication signal stream can be achieved through one or more transmitters and one or more receivers. If the number of transmitters is one, the transmitter needs to be equipped with multiple antennas (the number of antennas is greater than or equal to 2, and 2 antennas are used as an example in Figure 3); if the number of transmitters is multiple (the number of transmitters is greater than or equal to 2), these transmitters can be equipped with a single antenna or multiple antennas. The receiver can be equipped with a single antenna or multiple antennas (2 antennas are used as an example in Figure 3). In addition, assuming that there is an unauthorized user in the environment, the embodiment of the present application is applicable to the scenario where the unauthorized user is configured with any number of antennas (taking 2 antennas as an example in Figure 3), the location of the unauthorized user is unknown, and the unauthorized user attempts to achieve perception by receiving the transmission signal of the sending node.

[0096] In this communication system, a first communication device uses an encryption function to map K communication signal streams into N communication signal streams, thereby encrypting the physical layer communication signals with low implementation complexity. The K first communication signal streams can be independent signal streams that can be used to carry information, i.e., information can be transmitted via communication signals without changing the communication process of the communication link, thus reducing the impact on communication services. Furthermore, when a user is communicating, unauthorized users receive the N communication signal streams rather than the initial K communication signals. This can protect the perceived privacy of the target in scenarios where the user is conducting communication services, thereby improving the protection of perceived privacy.

[0097] The embodiments of this application do not limit the device form factor of the network device. The device used to implement the function of the network device can be a network device; it can also be a device that supports the network device to implement the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device. In the embodiments of this application, the chip system can be composed of chips or can include chips and other discrete components.

[0098] The following will specifically describe the interaction process between each network element / device in the above communication system through a method embodiment in conjunction with Figure 4. The signal transmission method provided in the embodiment of the present application can be applied to the above communication system and specifically applied to various scenarios / processes mentioned in the above communication system, which are described in detail below.

[0099] Figure 4 is a flow chart of a method for transmitting a signal provided in an embodiment of the present application. The method for transmitting a signal is applicable to the above-mentioned communication system, and mainly involves interaction between a first communication device and a second communication device.

[0100] As shown in FIG4 , the flow of the signal transmission method is as follows:

[0101] S401: A first communication device obtains K first communication signal streams.

[0102] Wherein, K is an integer greater than or equal to 1, and the K first communication signal streams can be K modulation symbol streams into which the first communication device maps the bit stream. The modulation symbol corresponds to the energy of the communication signal. The modulation symbol can be a symbol formed by combining bit mapping through modulation technology. The modulation symbol can carry a certain number of bits of information. A modulation symbol contains at least one bit of information, which is specifically determined by the modulation method. The modulation symbol stream can specifically be a series of continuous modulation symbols. The K first communication signal streams are used to carry information, and the signals on each subcarrier in the K first communication signal streams can be constellation points x1, x2, ..., x taken from a fixed signal set. KFor example, they can be constellation points taken from a 64QAM (quadrature amplitude modulation) constellation diagram, or they can be random constellation points with a constant modulus. There are multiple ways for the first communication device to obtain the K first communication signal streams. For example, they can be issued by a higher layer, obtained based on a trigger condition (such as the need to establish a service or transmit service data), or obtained according to a protocol definition, and there are no specific limitations on this.

[0103] It can be understood that the communication signal flow in the embodiments of the present application can be replaced by expressions such as data flow, codeword, etc.

[0104] S402: The first communication device maps K first communication signal streams into N communication signal streams according to a first encryption function to obtain mapped signals.

[0105] Among them, N communication signal streams correspond to N antenna ports and / or N communication signal streams correspond to N layers, N is a positive integer, and N is greater than K.

[0106] S403: The first communication device transmits the mapped signal.

[0107] S404: The second communication device obtains the mapped signal.

[0108] The mapped signal can reach the second communication device through the channel, and the second communication device can receive the mapped signal through M antennas equipped therewith, where M is a positive integer. The mapped signal may include N communication signal streams, for example, it may be a linear combination of N communication signal streams, and the coefficients of the linear combination are the values ​​of the channels transmitting the N communication signal streams. The N communication signal streams are obtained based on the mapping of the K first communication signal streams and the first encryption function, and the N communication signal streams correspond to the N antenna ports of the sending node and / or the N communication signal streams correspond to the N layers of the sending node. The sending node here is the first communication device.

[0109] S405: The second communication device demodulates the mapped signal according to the first encryption function to obtain K first communication signal streams.

[0110] In summary, an encryption function is used to map K communication signal streams into N communication signal streams, thereby achieving encryption of the physical layer communication signals with low implementation complexity. The K first communication signal streams can be independent signal streams that can be used to carry information, i.e., information can be transmitted via communication signals without changing the communication process of the communication link, thus reducing the impact on communication services. Furthermore, when a user is communicating, an unauthorized user receives the N communication signal streams rather than the initial K communication signals. This can protect the target's perceived privacy in scenarios where the user is conducting communication services, thereby improving the protection of perceived privacy.

[0111] S402 is introduced in detail below.

[0112] The N communication signal streams can be a linear combination of the K first communication signal streams. Therefore, relative to the N communication signal streams, the K first communication signal streams are independent communication signal streams used to carry information, while the N communication signal streams are not independent communication signal streams and do not carry additional information. That is, the N communication signal streams do not carry information other than that carried by the K first communication signal streams. N is an integer greater than or equal to 2, and K is a positive integer less than N.

[0113] In one possible implementation, the value of N can be determined based on the number of antennas equipped by the sending node (i.e., the first communication device), where N is less than or equal to the number of antennas equipped by the first communication device. For example, the first communication device is equipped with Y antennas, and Y is greater than or equal to N. Correspondingly, the maximum number of antenna ports of the first communication device is Y. The N communication signal streams can be communication signal streams of N antenna ports, and the corresponding maximum number of layers in the layer mapping stage is Y. Therefore, the N communication signal streams can also be communication signal streams of N layers.

[0114] Optionally, N may be the maximum number of spatial signal streams that a legal communication link can carry, N is greater than or equal to 2, and K is less than N, that is, K is greater than or equal to 1.

[0115] In one possible implementation, the value of K can be determined based on the channel quality of the signal transmitted by the sending node (i.e., the first communication device). Optionally, K is the number of channels that can independently transmit communication signal streams. For example, the channel matrix is ​​subjected to singular value decomposition. The larger the singular value, the better the quality of the corresponding channel. The number of non-zero singular values ​​represents the number of channels that can independently transmit communication signal streams. Therefore, K is determined based on the number of non-zero singular values. Of course, K can also be any positive integer that is less than or equal to the number of channels that can independently transmit communication signal streams.

[0116] Optionally, as shown in Figure 5, the encryption mapping method for the communication signal stream in the embodiment of the present application can be implemented by adding a signal encryption module before the layer mapping module. After the first communication device maps the bit stream into K modulation symbol streams (communication signal streams), it maps the K communication signal streams into N communication signal streams according to the encryption mapping method described in the embodiment of the present application, and then transmits them through subsequent processing modules such as layer mapping, antenna port mapping, beamforming, resource mapping, and orthogonal frequency division multiplexing (OFDM).

[0117] Optionally, the encryption mapping method for the communication signal stream (codeword) in the embodiment of the present application can also be implemented based on the layer mapping module, which can be achieved by redefining the layer mapping rules. A possible layer mapping rule is shown in Table 1:

[0118] Table 1: Layer mapping rules

[0119] It can be seen that 1, 2, 3, ..., N correspond to the N layers of the layer mapping module, x′1, x′2, ..., x′ N To map N-layer communication signal streams on N layers, the first communication device maps the bit stream into K modulation symbol streams, and the layer mapping module maps the K modulation symbol streams into N-layer communication signal streams.

[0120] Optionally, the encryption mapping method for the communication signal stream (codeword) in the embodiment of the present application can also be implemented based on the antenna port mapping module, which can be achieved by redefining the antenna port mapping rules. A possible antenna port mapping rule is shown in Table 2:

[0121] Table 2: Antenna port mapping rules

[0122] It can be seen that y1,y,...,y N Corresponding to the N antenna ports of the antenna port mapping module, when the communication signal stream encryption is implemented based on the antenna port mapping module, the antenna port mapping module receives the K layers of communication signal streams x1, x2, ..., x corresponding to the K layers of the layer mapping module. K The antenna port mapping module maps the K-layer communication signal stream to the communication signal streams x′1, x′2,…, x′ of N antenna ports. N .

[0123] In this way, the target's perceived privacy can be protected based on the existing wireless communication system structure.

[0124] Two possible implementations of S402 are described below.

[0125] In one possible implementation, the first communication device performs a first linear mapping transformation on the K first communication signal streams according to the first encryption function to obtain N mapped communication signal streams. The first linear mapping transformation may include:

[0126] in, is the first encryption function, x1,x2,…,x K are K first communication signal streams, t i is the current time or the sampling time of sampling the first encryption function, t iThe time unit can be a moment, such as a second, millisecond, etc., or it can be a sequence number such as a symbol, time slot, subframe, or frame in the time domain. N There are N communication signal flows.

[0127] It can be seen that the above is a method for determining the first encryption function. The K first communication signal streams are linearly combined through the first communication device to realize the encryption of the K first communication signal streams. The coefficients of the linear combination can be the sampling values ​​of the first encryption function in time, wherein the first encryption function can be a function matrix composed of multiple sub-functions, and the sampling values ​​of the first encryption function can include the sampling values ​​of multiple sub-functions at the current moment or the sampling moment.

[0128] Optionally, the first encryption function can be a time-varying function with a low-pass characteristic, that is, the spectrum of the first encryption function has at least one low-frequency component, and the frequency of the low-frequency component is close to the frequency characteristics of the perceived target, wherein the frequency characteristics of the perceived target can be frequency characteristics of the perceived target with periodic motion characteristics, such as heart rate, breathing frequency, walking frequency, etc. For example, in the scenario of perceiving the target's breathing frequency, the frequency of the low-frequency component of the spectrum of the first encryption function should be close to the target's breathing frequency. In this way, when the communication signal is encrypted, the target's breathing frequency is masked in the power spectrum of the signal measured by unauthorized users, thereby protecting the target's perceived privacy.

[0129] Optionally, the first encryption function is encrypted and shared by the sending node and the receiving node. The sending node here can be a first communication device, and the receiving node can be a second communication device. Encryption sharing can refer to the first encryption function being encrypting by a key by a high layer, and sending the encrypted first encryption function to the sending node and the receiving node. For example, the first encryption function can be encrypted by a key during the stage of sending a radio resource control protocol (RRC) reconfiguration message (RRC-Reconfiguration) by the high layer, and then the first encryption function is shared and exchanged. Encryption sharing can also be the first communication device and the second communication device interacting and sharing the first encryption function in an encrypted manner in advance. The encrypted shared information may include the function type and parameters of the first encryption function. In this way, it can be ensured that the second communication device can correctly demodulate the K first communication signal streams according to the first encryption function.

[0130] For example, taking K=2 and N=3 as an example, when the sending node of the communication link communicates with the receiver, the signals of the two independent communication signal streams transmitted by the sending node are x1 and x2 respectively. If the current time is t i, the sending node uses the first linear mapping transformation to map the two independent communication signal streams into three communication signal streams to achieve signal encryption. The specific formula is as follows:

[0131] The sending node sends the encrypted signals x′1, x′2, x′3, and the signals y1 and y2 received by each antenna of the receiver are as follows: y1 = h 11 x′1+h 12 x′2+h 13 x′3 = (α 11 (t i )h 11 +α 21 (t i )h 12 +α 31 (t i )h 13 )x1+(α 12 (t i )h 11 +α 22 (t i )h 12 +α 32 (t i )h 13 )x2, y2=h 21 x′1+h 22 x′2+h 23 x′3 = (α 11 (t i )h 21 +α 21 (t i )h 22 +α 31 (t i )h 23 )x1+(α 12 (t i )h 21 +α 22 (t i )h 22 +α 32 (t i )h 23 )x2

[0132] Since the sending node and the receiver encrypt and share the encryption function α in advance 11 (t i ),α 12 (t i ),α 21 (t i ),α 22 (t i ),α 31(t i ),α 32 (t i ) function type and parameters, and the receiver has estimated the channel h in advance 11 ,h 12 ,h 13 ,h 21 ,h 22 ,h 23 , so the receiver can correctly demodulate the signals x1, x2.

[0133] In another possible implementation, the first encryption function may include a second encryption function and a power allocation factor for each of the K first communication signal streams. The first communication device maps the K first communication signal streams into N communication signal streams based on the second encryption function and the power allocation factor to obtain a mapped signal.

[0134] The power allocation factor of each of the K first communication signal streams represents the power allocation requirement of each communication signal stream. The power allocation requirement here can be determined based on communication service requirements, which can be determined based on historical channel estimation results and the perceived privacy that needs to be protected. The first encryption function can be composed of the second encryption function and the power allocation factor. In other words, the first encryption function can be determined by the communication service requirements of the communication link.

[0135] Optionally, the N communication signal streams may include K second communication signal streams and NK third communication signal streams, wherein the K second communication signal streams are obtained by mapping the K first communication signal streams according to the power allocation factor, and the NK third communication signal streams are obtained by mapping the K first communication signal streams according to the second encryption function.

[0136] The first communication device performs a second linear mapping transformation on K1 first communication signal streams among the K first communication signal streams according to the second encryption function, performs a second linear mapping transformation on K-K1 first communication signal streams other than the K1 first communication signal streams among the K first communication signal streams according to the first coefficient, and performs a second linear mapping transformation on the K first communication signal streams according to the power allocation factor to obtain N mapped communication signal streams. The second linear mapping transformation may include:

[0137] Among them, α 1,1 (t i ),α 1,2 (t i ),…,α N-K,K1 (t i ) is the second encryption function, β 1,K1+1 ,β 1,K1+2 ,...,β N-K,Kis the first coefficient, P1(t i ),P2(t i ),...,P K (t i ) is the power allocation factor of each communication signal flow in the K first communication signal flows, x1, x2, ..., x K are K first communication signal streams, t i is the current time or the sampling time of sampling the second encryption function, t i The time unit can refer to the description of the first encryption function above, x′1, x′2, ..., x′ N There are N communication signal flows.

[0138] It can be understood that the K1 first communication signal streams may be part or all of the K first communication signal streams, for example, x1, x2, ..., x K1 ,x K1+1 …,x K The first K1 communication signal streams x1, x2, ..., x K1 That is, a second linear mapping transformation can be performed on some independent signal streams according to the second encryption function. For example, the first K1=1 first communication signal streams out of K=2 first communication signal streams can be subjected to the second linear mapping transformation, and the remaining K-K1=1 communication signal streams can be subjected to the second linear mapping transformation according to the first coefficient, wherein the first coefficient can be any value, that is, any constant, and is not limited here. The first coefficient is encrypted and shared by the sending node and the receiving node, that is, encrypted and shared by the first communication device and the second communication device. The encryption sharing method of the first coefficient can refer to the first encryption function. Therefore, the second communication device can demodulate K first communication signal streams according to the second encryption function and the first coefficient. By encrypting and mapping K1 communication signal streams out of the K first communication signal streams and mapping the remaining communication signal streams using the first coefficient, K1 second encryption functions and K-K1 constants can be exchanged during the encryption sharing process, which can reduce the interaction overhead and storage overhead.

[0139] It can be seen that N communication signal streams x′1, x′2, ..., x′ N It can be divided into the first K second communication signal streams and the last NK third communication signal streams, that is, x′1, x′2,…, x′ K ,x′ K+1 ,…,x′ N , where the first K second communication signal streams x′1, x′2,…, x′ K , is obtained by mapping the K first communication signal streams according to the power allocation factor, and the subsequent NK communication signal streams x′ K+1 ,x′ K+2 ,…,x′N The K first communication signal streams are mapped according to the second encryption function and the first coefficient. The K first communication signal streams are mapped according to the power allocation factor and the second encryption function, respectively, to achieve the power allocation requirement while also encrypting the communication signal stream. Since unauthorized users cannot receive the partial signal streams x′1, x′2, …, x′ mapped by the power allocation factor separately. K , and the signal stream received by the unauthorized user is x′1,x′2,…,x′ N , that is, N communication signal streams encrypted by the second encryption function, so that unauthorized users cannot obtain perception information through the received signal streams.

[0140] In the case of K=K1, the first communication device performs a second linear mapping transformation on the K first communication signal streams according to the second encryption function, and performs a second linear mapping transformation on the K first communication signal streams according to the power allocation factor to obtain N mapped communication signal streams. The second linear mapping transformation may include:

[0141] Among them, α 1,1 (t i ),α 1,2 (t i ),…,α N-K,K (t i ) is the second encryption function, P1(t i ),P2(t i ),…,P K (t i ) is the power allocation factor of each communication signal flow in the K first communication signal flows, x1, x2, ..., x K are K first communication signal streams, t i is the current time or the sampling time of sampling the second encryption function, t i The time unit can refer to the description of the first encryption function above, x′1, x′2, ..., x′ N There are N communication signal flows.

[0142] It can be seen that when K=K1, the first K second communication signal streams among the N communication signal streams are obtained by mapping the K first communication signal streams according to the power allocation factor, and the last NK communication signal streams are obtained by mapping the K first communication signal streams according to the second encryption function.

[0143] S403 is introduced in detail below.

[0144] The first communication device transmits K second communication signal streams and NK third communication signal streams, wherein a singular value corresponding to a channel transmitting the K second communication signal streams is greater than a singular value corresponding to a channel transmitting the NK third communication signal streams, and the singular value may be obtained by performing singular value decomposition on a channel matrix.

[0145] Before transmitting the communication signal, the first communication device and the second communication device perform channel estimation. For details, please refer to the process of channel estimation based on pilot symbols below. The second communication device estimates the channel matrix and feeds it back to the first communication device. The first communication device performs singular value decomposition on the channel matrix to obtain N singular values. The N singular values ​​are arranged in order from large to small. For example, the N singular values ​​are arranged in order from large to small, respectively, σ1, σ2, ..., σ K ,σ K+1 ,...,σ N , among the N singular values, the first K largest singular values ​​σ1,σ2,...,σ K K second communication signal streams are transmitted on the corresponding channel, and the largest singular value σ is used. K+1 ,σ K+2 ,...,σ N The corresponding channels transmit NK third communication signal streams to achieve privacy protection. The channels corresponding to larger singular values ​​are used to transmit independent communication signal streams used to carry information. This minimizes signal transmission rate loss and has a lower impact on communication performance. It can be understood that the larger the singular value after performing singular value decomposition on the channel matrix, the faster the signal transmission rate of the channel corresponding to the singular value, the lower the bit error rate, and thus the better the transmission performance.

[0146] In one possible implementation, the signal transmission method may further include: before transmitting the K second communication signal streams and the NK third communication signal streams, the first communication device obtains K pilot symbols. The first communication device maps the K pilot symbols into N pilot symbols according to a third encryption function to obtain mapped pilot symbols, and the mapped pilot symbols are used for channel estimation. The first communication device transmits the mapped pilot symbols and receives a channel matrix obtained through channel estimation.

[0147] It can be understood that before the sender and receiver communicate, the first communication device and the second communication device first perform channel estimation, specifically based on the pilot symbol. For example, the sending node (first communication device) sends a signal to the second communication device through three antenna ports, and the receiver (second communication device) receives the signal of the first communication device through two antennas. Assume that the pilot symbols transmitted by each antenna of the sending node are p1, p2, and p3 respectively. In one transmission time slot, the signals received by each antenna of the receiver are: y1 = h 11 p1+h 12 p2+h13 p3, y2=h 21 p1+h 22 p2+h 23 p3,

[0148] The receiver can estimate the channel h based on the pilot symbols sent by the sending node in multiple time slots. 11 ,h 12 ,h 13 ,h 21 ,h 22 ,h 23 .

[0149] Based on the above channel estimation process, the pilot symbols are encrypted according to the third encryption function. The encryption mapping method of the pilot symbols according to the third encryption function can refer to the encryption mapping method of the K first communication signals.

[0150] Optionally, the third encryption function may be the same as the first encryption function, or may be different from the first encryption function.

[0151] When the third encryption function is different from the first encryption function, the encryption mapping method for the pilot symbols according to the third encryption function can refer to the encryption mapping method for the K first communication signals. For example, in the channel estimation phase, the first communication device transmits a signal to the second communication device via three antenna ports, and the second communication device receives the signal from the first communication device via two antennas. Assuming that the original pilot symbols of the first communication device are p1 and p2, the pilot symbols are encrypted using the following method before transmission:

[0152] in, is the third encryption function, t i is the current time or the sampling time of sampling the third encryption function, t i The time unit can refer to the above description of the first encryption function, and p′1, p′2, and p′3 are three pilot symbols after encryption mapping.

[0153] In one transmission time slot, the signal received by each antenna of the second communication device is:

[0154] The third encryption function is encrypted and shared by the sending node and the receiving node, that is, The function type and parameters of the first communication device and the second communication device are encrypted and shared. The encryption sharing method of the third encryption function can refer to the first encryption function. Therefore, the second communication device can estimate the equivalent channel h′ based on the pilot symbol. 11 ,h′ 12 ,h′ 21 ,h′ 22, and then demodulate the channel h according to the third encryption function 11 ,h 12 ,h 13 ,h 21 ,h 22 ,h 23 .

[0155] Afterwards, the first communication device and the second communication device begin to communicate. Assume that the first communication device transmits K = 2 independent communication signal streams, x1 and x2 respectively. The second communication device then uses the following method to map the two independent communication signal streams into N = 3 communication signal streams to achieve signal encryption:

[0156] The first communication device sends an encrypted signal, and the signals received by each antenna of the second communication device are as follows:

[0157] Since the first communication device and the second communication device encrypt and share the encryption function in advance The function type and parameters and other information, and the second communication device has estimated the channel h in advance 11 ,h 12 ,h 13 ,h 21 ,h 22 ,h 23 , so the receiver can correctly demodulate the signals x1, x2.

[0158] In this way, sending the mapped pilot symbols in the channel estimation phase can prevent unauthorized users from achieving perception by measuring the pilot symbols, thereby enhancing the protection of user perception privacy.

[0159] If the third encryption function is the same as the first encryption function, that is, the pilot symbol and the K first communication signals are encrypted using the same encryption function, the third encryption function may be a time-varying function with a low-pass characteristic, and may refer to the first encryption function.

[0160] In one possible implementation, a first sampled value of a first encryption function is used in mapping K first communication signal streams into N communication signal streams. The first sampled value is obtained by sampling the first encryption function at a first moment. A second sampled value of a third encryption function is used in mapping K pilot symbols into N pilot symbols. The second sampled value is obtained by sampling the third encryption function at a second moment. When the first and third encryption functions are the same, the interval between the first and second moments is within a preset time period, and the first and second sampled values ​​are the same during the preset time period.

[0161] It can be understood that the preset time period can be a time interval that ensures that the first sampling value is the same as the second sampling value. If the first encryption function and the third encryption function are the same, then in order to ensure that the second communication device can correctly demodulate, the sampling values ​​of the encryption functions of the pilot symbols and the communication signals need to remain unchanged within one frame or multiple frames, that is, the sampling values ​​of the encryption functions used in the two stages of channel estimation and communication are the same, so that the channel estimation stage only needs to estimate the equivalent channel, and the communication stage can achieve demodulation through the equivalent channel and the third encryption function, thereby reducing the overhead in the channel estimation process.

[0162] For example, in the channel estimation stage, assuming that the original pilot symbols of the first communication device are p1, p2, and the communication frame number is T i , the current communication frame number is T1, and the pilot symbol is transmitted after being encrypted in the following manner:

[0163] in, is the first sampling value of the third encryption function that is the same as the first encryption function at the first time (T1), and p′1, p′2, and p′3 are three pilot symbols after encryption mapping.

[0164] In one transmission time slot, the signal received by each antenna of the second communication device is:

[0165] The second communication device can estimate the equivalent channel h′ based on the pilot symbol 11 ,h′ 12 ,h′ 21 ,h′ 22 .

[0166] Afterwards, the first communication device and the second communication device begin communicating. Assuming the first communication device transmits K = 2 independent communication signal streams, x1 and x2, respectively, and the current communication frame number is T2, the second communication device then uses the following method to map the two independent communication signal streams into N = 3 communication signal streams to achieve signal encryption:

[0167] in, is the second sampling value of the first encryption function at the second time (T2), and x′1, x′2, and x′3 are the three communication signal streams after encryption mapping.

[0168] The first communication device sends the mapped signal, and the signals received by each antenna of the second communication device are as follows: y1 = h 11 x′1+h 12 x′2+h 13 x′3 = (α 11 (T2)h 11 +α 21(T2)h 12 +α 31 (T2)h 13 )x1 +(α 12 (T2)h 11 +α 22 (T2)h 12 +α 32 (T2)h 13 )x2=h′ 11 x1+h′ 12 x2 y2=h 21 x′1+h 22 x′2+h 23 x′3 = (α 11 (T2)h 21 +α 21 (T2)h 22 +α 31 (T2)h 23 )x1+(α 12 (T2)h 21 +α 22 (T2)h 22 +α 32 (T2)h 23 )x2 =h′ 21 x1+h′ 22 x2

[0169] Since the first communication device and the second communication device encrypt and share the encryption function α in advance 11 (t i ),α 12 (t i ),α 21 (t i ),α 22 (t i ),α 31 (t i ),α 32 (t i ), and the interval between the first moment and the second moment is within the preset time period, the first sampling value of the first encryption function at the first moment is the same as the second sampling value of the third encryption function at the second moment, and the second communication device calculates the equivalent channel h′ according to the pre-estimated equivalent channel h′. 11 ,h′ 12 ,h′ 21 ,h′ 22 The signals x1 and x2 can be demodulated correctly, reducing the overhead in the channel estimation process.

[0170] The above, combined with Figures 4 and 5, illustrates the overall process of the signal transmission method provided by the embodiments of the present application. To prevent unauthorized users from dividing the received signals from multiple antennas in an attempt to remove the influence of the encryption function and thereby achieve perceived privacy, the first encryption function can take a specific form in specific scenarios. The following, combined with Figures 6 and 7, details the possible forms that the first encryption function provided by the embodiments of the present application can take in specific scenarios.

[0171] Scenario 1:

[0172] Continuing with the above example where a sending node transmits signals through three antenna ports and a receiving node receives signals through two antenna ports, let's assume the unauthorized user is equipped with two antennas. The embodiments of this application are also applicable to scenarios where the unauthorized user is equipped with multiple antennas. For example, if the unauthorized user obtains the breathing frequency of the perceived target, if the communication signal is not encrypted, as shown in Figure 6, the unauthorized user may be able to identify the spectral peak of the actual breathing signal from the power spectrum of the received signal.

[0173] At this time, the first encryption function can take the following form (or other valid forms): α 11(t) =α 12 (t) = α 21 (t) = α 22 (t)=1

[0174] Where, θ(t)=πcos(2πF a t) is a time-varying function with low-pass characteristics, and its frequency F a The breathing frequency of the target is close to that of the target. As shown in FIG7 , when the first encryption function takes the above form, a false spectral peak can be generated in the power spectrum of the signal received by the unauthorized user, and the intensity of the false spectral peak is much higher than the spectral peak of the real breathing signal. The unauthorized user cannot identify the real frequency characteristics, thereby achieving the effect of privacy protection.

[0175] Scenario 2:

[0176] Continuing with the above example where the sending node transmits signals through three antenna ports and the receiving node receives signals through two antenna ports, it is assumed that the unauthorized user is equipped with two antennas. The embodiments of the present application are also applicable to scenarios where the unauthorized user is equipped with multiple antennas. For example, if the unauthorized user obtains the gestures, gait, and other motion behaviors of the perceived target, the first encryption function can take the following form (other valid forms may also be taken): α 11(t) =α 12 (t) = α 21 (t) = α 22 (t)=1

[0177] Where θ(t)=sinc(2πF b t) is a time-varying function with low-pass characteristics, Parameter F of θ(t) b This is comparable to the maximum Doppler shift caused by the target's motion.

[0178] When the first encryption function takes the above form, a false spectrum peak can be generated in the power spectrum of the signal received by the unauthorized user, thereby achieving the effect of privacy protection.

[0179] The method provided by the embodiment of the present application is described in detail above with reference to Figures 4 to 7. The communication device for executing the signal transmission method provided by the embodiment of the present application is described in detail below with reference to Figures 8 to 9.

[0180] Figure 8 is a structural diagram of a communication device according to an embodiment of the present application. As shown in Figure 8 , the communication device 800 includes a transceiver module 801 and a processing module 802. For ease of illustration, Figure 8 only shows the main components of the communication device.

[0181] The transceiver module 801 is used to perform the transceiver function of the method shown in FIG. 4 , and the processing module 802 is used to perform other functions of the method shown in FIG. 4 except the transceiver function.

[0182] Optionally, the transceiver module 801 may include a sending module (not shown in FIG8 ) and a receiving module (not shown in FIG8 ). The sending module is used to implement the sending function of the communication device 800 , and the receiving module is used to implement the receiving function of the communication device 800 .

[0183] Optionally, the communication device 800 may further include a storage module (not shown in FIG8 ) that stores a program or instruction. When the processing module 802 executes the program or instruction, the communication device 800 may perform the functions of the terminal or network device in the method shown in FIG4 in the above method.

[0184] It can be understood that the communication device 800 can be a terminal or a network device, or a chip (system) or other parts or components that can be set in a terminal or a network device, or a device that includes a terminal or a network device. This application does not limit this.

[0185] In addition, the technical effects of the communication device 800 can refer to the technical effects of the signal transmission method shown in Figures 4 and 5, and will not be repeated here.

[0186] Figure 9 is a second structural diagram of a communication device provided in an embodiment of the present application. Exemplarily, the communication device may be a terminal, or a chip (system) or other component or assembly that can be set in a terminal. As shown in Figure 9, the communication device 900 may include a processor 901. Optionally, the communication device 900 may further include a memory 902 and / or a transceiver 903. The processor 901 is coupled to the memory 902 and / or the transceiver 903, such as by connecting via a communication bus, by connecting via an interface within the chip, or by connecting via other communication lines. Optionally, the memory 902 may be integrated with the processor 901.

[0187] The following is a detailed introduction to the various components of the communication device 900 in conjunction with FIG9 :

[0188] The processor 901 is the control center of the communication device 900 and can be a single processor or a collective term for multiple processing elements. For example, the processor 901 can be one or more central processing units (CPUs), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more digital signal processors (DSPs) or one or more field programmable gate arrays (FPGAs).

[0189] Optionally, the processor 901 may execute various functions of the communication device 900 , such as executing the signal transmission method shown in FIG. 4 , by running or executing a software program stored in the memory 902 and calling data stored in the memory 902 .

[0190] In a specific implementation, as an embodiment, the processor 901 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 9 .

[0191] In a specific implementation, as an embodiment, the communication device 900 may also include multiple processors, such as the processor 901 and the processor 904 shown in FIG9 . Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0192] The memory 902 is used to store the software program for executing the solution of the present application, and the execution is controlled by the processor 901. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0193] Optionally, the memory 902 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 902 can be integrated with the processor 901 or exist independently and be coupled to the processor 901 through the interface circuit of the communication device 900 (not shown in Figure 9). This embodiment of the present application does not specifically limit this.

[0194] Transceiver 903 is used for communication with other communication devices. For example, if communication device 900 is a terminal, transceiver 903 can be used to communicate with a network device or another terminal device. For another example, if communication device 900 is a network device, transceiver 903 can be used to communicate with a terminal or another network device.

[0195] Optionally, the transceiver 903 may include a receiver and a transmitter (not shown separately in FIG9 ), wherein the receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

[0196] Optionally, the transceiver 903 may be integrated with the processor 901 or exist independently and be coupled to the processor 901 through an interface circuit (not shown in FIG. 9 ) of the communication device 900 . This embodiment of the present application does not specifically limit this.

[0197] It is understandable that the structure of the communication device 900 shown in FIG9 does not constitute a limitation on the communication device, and an actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0198] In addition, the technical effects of the communication device 900 can refer to the technical effects of the methods described in the above method embodiments, and will not be repeated here.

[0199] It should be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), and the processor may also be other general-purpose processors, DSPs, ASICs, FPGAs or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0200] It should also be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a ROM, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an EEPROM, or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0201] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (such as 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 contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0202] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0203] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0204] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0205] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0206] 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.

[0207] 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 the units is merely 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.

[0208] The units described as separate components may or may not be physically separate, and the 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.

[0209] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0210] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes the various possible memories mentioned above.

Claims

1. A method for transmitting a signal, characterized in that, Including: Obtaining K first communication signal streams; Mapping the K first communication signal streams into N communication signal streams according to a first encryption function to obtain the mapped signals, where the N communication signal streams correspond to N antenna ports and / or the N communication signal streams correspond to N layers, and K and N are positive integers, and K is less than N; Transmitting the mapped signals.

2. The method according to claim 1, wherein Mapping the K first communication signal streams into N communication signal streams according to a first encryption function to obtain the mapped signals, including: Performing a first linear mapping transformation on the K first communication signal streams according to the first encryption function to obtain the mapped N communication signal streams.

3. The method according to claim 2, characterized in that, The first linear mapping transformation includes: Among them, is the first encryption function, x1, x2... x K are the K first communication signal streams, t i is the current time or the sampling time for sampling the first encryption function, x′1, x′2... x′ N are the N communication signal streams.

4. The method according to claim 1, wherein The first encryption function includes a second encryption function and power distribution factors of each communication signal stream in the K first communication signal streams. Mapping the K first communication signal streams into N communication signal streams according to the first encryption function to obtain the mapped signals further includes: Mapping the K first communication signal streams into N communication signal streams according to the second encryption function and the power distribution factors to obtain the mapped signals.

5. The method according to claim 4, wherein The N communication signal streams include K second communication signal streams and N-K third communication signal streams, where the K second communication signal streams are mapped from the K first communication signal streams according to the power distribution factors, and the N-K third communication signal streams are mapped from the K first communication signal streams according to the second encryption function.

6. The method according to claim 4 or 5, characterized in that Mapping the K first communication signal streams into N communication signal streams according to the second encryption function and the power distribution factors to obtain the mapped signals, including: Perform a second linear mapping transformation on K1 of the K first communication signal streams according to the second encryption function, perform a second linear mapping transformation on the K - K1 first communication signal streams other than the K1 first communication signal streams among the K first communication signal streams according to the first coefficient, and perform a second linear mapping transformation on the K first communication signal streams according to the power distribution factor to obtain N mapped communication signal streams, where the second linear mapping transformation includes: Among them, α 1,1 (t i ), α 1,2 (t i ),..., α N-K,K1 (t i ) are the second encryption functions, β 1,K1+1 , β 1,K1+2 ,..., β N-K,K are the first coefficients, P1(t i ), P2(t i ),..., P K (t i ) are the power distribution factors of each communication signal flow in the K first communication signal flows, x1, x2,..., x K are the K first communication signal flows, t i is the current moment or the sampling moment for sampling the second encryption function, x′1, x′2,..., x′ N are the N communication signal flows.

7. The method according to claim 5 or 6, characterized in that, The transmitting the mapped signals includes: Transmitting the K second communication signal streams and the N-K third communication signal streams; where the singular value corresponding to the channel for transmitting the K second communication signal streams is greater than the singular value corresponding to the channel for transmitting the N-K third communication signal streams, and the singular value is obtained by performing singular value decomposition on the channel matrix.

8. The method according to claim 7, characterized in that, Before transmitting the K second communication signal streams and the N-K third communication signal streams, the method further includes: Obtaining K pilot symbols; Mapping the K pilot symbols into N pilot symbols according to a third encryption function to obtain the mapped pilot symbols, where the mapped pilot symbols are used for channel estimation; Sending the mapped pilot symbols and receiving the channel matrix obtained through channel estimation.

9. The method according to claim 8, wherein The first encryption function and the third encryption function are the same, or the first encryption function and the third encryption function are different.

10. The method according to claim 9, wherein During the process of mapping the K first communication signal streams into N communication signal streams, the first sampling value of the first encryption function is used, and the first sampling value is obtained by sampling the first encryption function at the first moment; during the process of mapping the K pilot symbols into N pilot symbols, the second sampling value of the third encryption function is used, and the second sampling value is obtained by sampling the third encryption function at the second moment; When the first encryption function is the same as the third encryption function, the interval between the first moment and the second moment is within a preset time period, and the first sampling value is the same as the second sampling value within the preset time period.

11. The method according to any one of claims 8 to 10, characterized in that, The third encryption function is encrypted and shared by the sending node and the receiving node.

12. The method according to any one of claims 8 to 11, characterized in that, The third encryption function is a time-varying function with a low-pass characteristic.

13. A method for transmitting a signal, characterized in that, Including: Obtain the mapped signal, where the mapped signal includes N communication signal streams, and the N communication signal streams are mapped based on K first communication signal streams and a first encryption function, and the N communication signal streams correspond to N antenna ports of the sending node and / or the N communication signal streams correspond to N layers of the sending node; Demodulate the mapped signal according to the first encryption function to obtain the K first communication signal streams.

14. The method according to claim 13, wherein The N communication signal streams are obtained by performing a first linear mapping transformation on the K first communication signal streams according to the first encryption function.

15. The method according to claim 14, wherein The first linear mapping transformation includes: Among them, is the first encryption function, x1, x2,..., x K are the K first communication signal streams, t i is the current time or the sampling time for sampling the first encryption function, x′1, x′2,..., x′ N are the N communication signal streams.

16. The method according to claim 13, wherein The first encryption function includes a second encryption function and a power distribution factor of each communication signal stream among the K first communication signal streams, and the N communication signal streams are mapped based on the K1 first communication signal streams, the second encryption function, and the power distribution factor.

17. The method according to claim 16, wherein The N communication signal streams include K second communication signal streams and N-K third communication signal streams, where the K second communication signal streams are mapped from the K first communication signal streams according to the power distribution factor, and the N-K third communication signal streams are mapped from the K first communication signal streams according to the second encryption function.

18. The method according to claim 16 or 17, characterized in that, The N communication signal streams are obtained by performing a second linear mapping transformation on K1 of the K first communication signal streams among the K first communication signal streams based on the second encryption function, performing a second linear mapping transformation on the K - K1 first communication signal streams other than the K1 first communication signal streams among the K first communication signal streams by a first coefficient, and performing a second linear mapping transformation on the K first communication signal streams based on the power distribution factor. The second linear mapping transformation includes: Among them, α 1,1 (t i ), α 1,2 (t i ),..., α N-K,K1 (t i ) is the second encryption function, β 1,K1+1 , β 1,K1+2 ,..., β N-K,K are the first coefficients, P1(t i ), P2(t i ),..., P K (t i ) are the power distribution factors of each communication signal flow in the K first communication signal flows, x1, x2,..., x K are the K first communication signal flows, t i is the current time or the sampling time for sampling the second encryption function, x′1, x′2,..., x′ N are the N communication signal flows.

19. The method according to claim 13, wherein Demodulating the mapped signal according to the first encryption function to obtain the K first communication signal streams includes: Demodulating the mapped signal according to the first encryption function and the channel to obtain the K first communication signal streams.

20. The method according to claim 19, wherein Before demodulating the mapped signal according to the first encryption function and the channel to obtain the K first communication signal streams, the method further includes: Obtain the mapped pilot symbol, where the mapped pilot symbol is mapped based on K pilot symbols and a third encryption function; Perform channel estimation according to the mapped pilot symbol and the third encryption function to obtain the channel.

21. The method according to claim 20, wherein The first encryption function is the same as the third encryption function, or the first encryption function is different from the third encryption function.

22. The method according to claim 21, wherein The first sampling value of the first encryption function is used in the process of mapping the K first communication signal streams to N communication signal streams, and the first sampling value is obtained by sampling the first encryption function at the first moment; the second sampling value of the third encryption function is used in the process of mapping K pilot symbols to N pilot symbols, and the second sampling value is obtained by sampling the third encryption function at the second moment; When the first encryption function is the same as the third encryption function, the interval between the first moment and the second moment is within a preset time period, and the first sampling value is the same as the second sampling value within the preset time period.

23. The method according to claim 21 or 22, characterized in that, When the first encryption function is the same as the third encryption function, the method further includes: Channel estimation is performed according to the mapped pilot symbols and the third encryption function to obtain an equivalent channel, and the equivalent channel has a corresponding relationship with the channel; The mapped signal is demodulated according to the first encryption function and the equivalent channel to obtain the K first communication signal streams.

24. The method according to any one of claims 20 to 23, characterized in that The third encryption function is encrypted and shared by the sending node and the receiving node.

25. The method according to any one of claims 20 to 24, characterized in that, The third encryption function is a time-varying function with low-pass characteristics.

26. The method according to any one of claims 1 to 25, characterized in that, The first encryption function is encrypted and shared by the sending node and the receiving node.

27. The method according to any one of claims 1 to 26, characterized in that, The first encryption function is a time-varying function with low-pass characteristics.

28. A communication device, characterized in that, The device includes a module for performing the method according to any one of claims 1-12, 26-27.

29. A communication device, characterized in that, The communication device includes a processor; the processor is configured to cause the communication device to perform the method according to any one of claims 1-12, 26-27 by executing a computer program (or computer-executable instructions) stored in a memory, and / or by a logic circuit.

30. The communication device according to claim 29, wherein, The communication device further includes the memory.

31. The communication device according to claim 30, characterized in that, The processor and the memory are integrated together.

32. The communication device according to any one of claims 29 to 31, characterized in that, The communication device further includes a communication interface for the communication device to communicate with other devices.

33. A communication device, characterized in that, The device includes a module for performing the method according to any one of claims 13-27.

34. A communication device, characterized in that, The communication device includes a processor; the processor is configured to cause the communication device to perform the method according to any one of claims 13-27 by executing a computer program (or computer-executable instructions) stored in a memory, and / or by a logic circuit.

35. The communication device according to claim 34, characterized in that, The communication device further includes the memory.

36. The communication device according to claim 35, wherein The processor and the memory are integrated together.

37. The communication device according to any one of claims 34 to 36, characterized in that, The communication device further includes a communication interface for the communication device to communicate with other devices.

38. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a computer program or instructions, and when the computer program or instructions run on a computer, the method according to any one of claims 1-27 is implemented.

39. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, the method according to any one of claims 1-27 is implemented.

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