A physical layer security control method, system, medium, device and terminal

Abstract

The present invention belongs to the field of physical layer security technology, and discloses a physical layer security control method, system, medium, device and terminal. Under the condition of simultaneous analysis of eavesdropping at the source node and the relay, a near user node is designed to be a relay node to forward information to the far user node, and a two-step relay selection scheme is designed. The optimal solution of the system confidentiality interruption probability is obtained through the two-step relay selection scheme. Under the condition of simultaneous consideration of eavesdropping at the source node and the relay, the present invention designs a near user node as a relay node to forward information to the far user node, and a two-step relay selection scheme is designed. While ensuring the reliable transmission of far user information, the data rate of near user information transmission is maximized. The physical layer security control method of the present invention can obtain better confidentiality and security performance, and the optimal solution of the system confidentiality interruption probability is obtained through the two-step relay selection scheme, which can obtain better confidentiality and security performance compared with the traditional random relay selection scheme.

Description

Technical Field

[0001] The present invention belongs to the field of physical layer security technology, and in particular relates to a physical layer security control method, system, medium, equipment and terminal. Background Art

[0002] At present, mobile communications are constantly reforming and updating to develop into the fifth generation of mobile communications. With the development of technologies such as microelectronics, users' access terminals are becoming more diversified, and users' requirements for service quality are also increasing. Faced with the explosive growth of user access devices and the diversification of users' needs for network communications, the scarcity of spectrum resources and the reduction of communication delays have become urgent issues to be solved in future communications. At the same time, the advent of the information age has made human work and life digitalized, and people have begun to frequently exchange private information through the Internet, which has brought information security to a new level. Ensuring the security of user privacy information has become an important research direction.

[0003] As one of the important development directions of information technology, the Internet of Things aims to connect everything. Connecting objects to the core network as a separate terminal can facilitate people's management of objects and form an intelligent and convenient management system, thereby greatly liberating manpower. However, the Internet of Things also increases the access pressure of the core network. In order to effectively meet the information exchange needs of each access terminal, the reliable access of all users must be guaranteed first. Users establish a connection with the base station through multiple access technology. This access technology divides different signal dimension resources such as spectrum and time slot into channels and then allocates them to users according to certain rules to ensure that multiple users can connect to the base station and exchange data at the same time. Multiple access methods are currently divided into two categories: orthogonal multiple access (OMA) and non-orthogonal multiple access. Since the first generation of wireless mobile communications, the technology for users to access the core network is OMA technology, and the channels in the OMA system have a mutually orthogonal relationship. Orthogonal multiple access technology only occupies a channel at the same time. When the communication resources remain unchanged, OMA makes the system capacity always fixed, which is difficult to meet the increasing access needs of users. In fact, the research on non-orthogonal multiple access technology has started since 2013, and since it can greatly improve spectrum efficiency and increase system capacity, it has received widespread attention from researchers since it was proposed. Currently proposed non-orthogonal multiple access technologies include power domain non-orthogonal multiple access (hereinafter referred to as power domain NOMA), sparse code multiple access (SCMA), multi-user shared access (MUSA), etc. The basic principle of non-orthogonal multiple access technology is to design different user access schemes in different dimensions, generate multi-user aliasing signals at the transmitter and transmit them into the air, and decode the desired message from the aliased messages of multiple users at the receiver through a specific decoding method.

[0004] There are many user devices in large-scale networks. Due to the obstruction of obstacles or shadow fading caused by long-distance transmission, there will be no direct transmission link between some base stations and users, which will make the user experience of some users at the edge of the cellular cell extremely poor and unable to obtain messages immediately, which may lead to some irreversible losses. Cooperative transmission technology is an effective way to solve this kind of problem. The principle of cooperative transmission technology is to establish a new transmission path independent of the direct transmission link between the source node and the destination node by introducing a relay channel, and to assist the communication of the source node. The use of cooperative transmission technology can re-establish the relay to the destination node link when the direct transmission link between the source node and the destination node is not available, and assist in completing the information exchange between the source node and the destination node. It can be seen that the use of cooperative transmission technology can improve the effectiveness of edge users. The combination of cooperative transmission technology and other technologies can achieve a significant increase in system capacity. For example, the introduction of cooperative transmission technology on the basis of the NOMA system constitutes a cooperative NOMA (Cooperative-NOMA, C-NOMA) system. The C-NOMA network allows multiple nodes to share resources, which has a very considerable effect in improving spectrum efficiency, increasing the number of user accesses and improving user fairness.

[0005] From the perspective of information security, due to the broadcast nature of wireless communication, all users within the signal receiving range will receive the message. If there are malicious users within the receiving range who receive and decode the message at the same time, user information may be leaked, thereby threatening the security of user information in the wireless communication network. For information encryption, traditional encryption methods are generally based on cryptography and perform encryption above the network layer. The key is that the two communicating parties need to establish a key channel in advance and share the key between the source and the destination. The two communicating parties decode the message with the key, and the eavesdropper cannot successfully decode the user message without the key. The secure transmission achieved by this type of encryption technology often authenticates the user identity multiple times before transmitting the information. The key is to continuously increase the amount of calculation required for key cracking. Generally, the higher the encryption level, the more constraints the encryption technology will have, and the additional costs such as transmission delay and key management costs will also rise sharply. However, wireless communication is developing towards ultra-high connection density and ultra-high data traffic. At this time, if confidential communication is added, the amount of encryption calculation will increase exponentially with the increase in the number of access devices, and the key management and identity authentication will become more complicated. In addition, the use of key encryption is based on the assumption that the eavesdropper's computing power is limited, and computing equipment is developing very rapidly. If quantum computers are successfully developed, it is only a matter of time before the key is cracked.

[0006] In order to ensure the security of user messages, information encryption has always been developed along with the development of communication technology. In addition to traditional upper-layer encryption, experts and scholars have also proposed the concept of physical layer security. Physical layer security takes the physical layer as the entry point, applies the basis of information theory to analyze the channel capacity, and increases the capacity of the legal link to deteriorate the eavesdropping link, thereby ensuring that the system has a positive confidentiality rate and obtaining a strategy for confidential transmission. There are several advantages to using physical layer security technology to encrypt messages. First, it can ensure higher security. The encryption capability of physical layer security technology does not depend on computing power. Even if the eavesdropping device has powerful computing power, it cannot decode the message, which can ensure the safe transmission of user information. Second, physical layer security technology directly realizes confidential transmission during data transmission, and can adjust the transmission strategy and parameters at any time during transmission to adapt to changes in the channel. It can be seen that physical layer security can effectively make up for the shortcomings of traditional encryption technology, reduce encryption costs, but achieve absolute security.

[0007] Therefore, in order to improve the capacity of the communication system, reduce communication latency, and ensure reliable communication of all access devices, studying the confidential transmission strategy of the collaborative NOMA system is an enduring hot issue.

[0008] Through the above analysis, the problems and defects of the prior art are as follows:

[0009] (1) Traditional encryption methods will continuously increase the amount of computation required to crack the key in the process of achieving secure transmission. The higher the degree of encryption, the higher the additional costs such as transmission delay and key management costs.

[0010] (2) Most existing studies focus on the case where the eavesdropper only eavesdrops on the source node sending messages or relaying messages, and few studies consider the case where the eavesdropper simultaneously eavesdrops on both stages of information transmission.

[0011] (3) There is little research in the existing literature on the physical layer security of systems in scenarios where nearby users act as relays to forward information to distant users. Summary of the invention

[0012] In response to the problems existing in the prior art, the present invention provides a physical layer security control method, system, medium, device and terminal, and in particular, relates to a physical layer security control method, system, medium, device and terminal based on a NOMA system.

[0013] The present invention is implemented as follows: a physical layer security control method, the physical layer security control method comprising:

[0014] In the case of eavesdropping at the source node and the relay, the design uses the near user node as a relay node to forward information to the far user node. Because different users require different QoS, this scheme designs a two-step relay selection scheme based on the different QoS requirements between the two users. Near users may transmit information with a higher data rate such as video, which requires higher performance requirements, while far users transmit information with a lower data rate such as text. Different QoS requirements are met by designing corresponding two-step relay selection schemes for different users, and the optimal solution for the probability of system confidentiality interruption is obtained through the two-step relay selection scheme.

[0015] Furthermore, the physical layer security control method comprises the following steps:

[0016] Step 1: Build a system model and improve the overall system transmission reliability by designing nearby users to act as relays to send information to distant users.

[0017] Step 2: Determine the transmission process based on the system model, and use the DF protocol as the relay forwarding protocol. This protocol will not amplify the noise at the node and has better performance.

[0018] Step 3: Design a two-step relay selection scheme TRS to perform step-by-step relay selection according to the QoS requirements of different users, thereby obtaining the optimal solution for the system confidentiality interruption probability.

[0019] Furthermore, the system model in step 1 includes a source node BS, N trusted DF relay nodes R1…R N , a remote user node D, and an illegal eavesdropper Eve. n Nodes and D-nodes have different data rate requirements. n The node needs a higher data rate to complete the transmission of confidential messages with large data volume, such as videos, while the D node needs a lower data rate to complete the transmission of confidential messages with small data volume, such as simple text. n , D's QoS requirements, R n , D are divided into near users and far users respectively. All nodes in the model are equipped with a single antenna, and relays R1…R N It works in half-duplex and DF mode. Considering the deep fading or obstacles caused by long-distance transmission, there is no direct link between the source node and the remote user node, and normal communication can only be completed through relay-assisted forwarding. The eavesdropper is located between the source node and the destination node and can eavesdrop on the messages sent by the source node and the relay at the same time.

[0020] make Represents BS to R n , R n to D, BS to Eve, R nTo Eve's channel coefficient. All channels obey complex Gaussian distribution, The noise at all nodes in the model is additive white Gaussian noise.

[0021] Furthermore, the transmission process in step 2 is divided into two stages, specifically including:

[0022] In the first stage, the source node S sends the superposition message of x1 and x2 in the form of NOMA. In the first stage, in the relay R1…R N , the messages Eve receives are:

[0023]

[0024]

[0025] Among them, P S is the power of the signal sent by the source node, α1 and α2 are NOMA power allocation factors and satisfy α1>α2, α1+α2=1. n SE are the AWGN at the relay and the eavesdropper, respectively, with a mean of 0 and a variance of

[0026] The serial interference cancellation technology in NOMA technology is used to decode information x1 and x2 respectively. The relay first uses information x2 as interference to decode information x1 and then decodes its own information:

[0027]

[0028]

[0029] Under the system model, when Eve has multi-user detection capability, parallel interference elimination PIC is used to decode aliased signals at the Eve node. Therefore, the signal-to-noise ratios of x1 and x2 decoded at Eve in the first stage are:

[0030]

[0031]

[0032] In the second stage, a relay is selected as a cooperative forwarding node and the DF protocol is used for forwarding. The signal received by the remote user is:

[0033]

[0034] Among them, P R is the transmit power of the relay node. is the noise at the relay node, with a mean of 0 and a variance of Then the SINR of the decoded information x1 at the far user D is:

[0035]

[0036] in, At the same time, the SINR of the decoded information x1 at the eavesdropper is:

[0037]

[0038] in,

[0039] Combining the two stages, the capacity of information x1 and x2 is obtained according to the calculation formula of safety capacity:

[0040]

[0041]

[0042] in, is the spectral efficiency factor.

[0043] Furthermore, for the eavesdropping link, the eavesdropper combines the signals of the two stages and obtains the capacities of the information x1 and x2 at the eavesdropping link as follows:

[0044]

[0045]

[0046] Then the confidentiality capacity of information x1 and x2 is:

[0047]

[0048]

[0049] Where [x] + =max{x,0}.

[0050] Furthermore, in the step three, a two-step relay selection scheme TRS is designed as the analysis content, and the optimal relay selection scheme ORS and the random relay selection scheme RRS are given as comparison schemes.

[0051] The two-step relay selection scheme includes two stages, which are used to ensure the successful transmission of the base station-far user link while maximizing the confidentiality rate of the base station-near user link.

[0052] In the first stage, a relay subset Sr is selected, in which all relays can guarantee the successful transmission of the remote user, which is expressed as follows:

[0053]

[0054] in, is the target rate of far user D.

[0055] Select a relay from Sr to maximize the confidentiality capacity of the near user information x2:

[0056]

[0057] Another object of the present invention is to provide a physical layer security control system using the physical layer security control method, the physical layer security control system comprising:

[0058] System model building module, used to build system model;

[0059] A transmission process determination module, used for determining the transmission process based on the system model;

[0060] The optimal solution determination module is used to design a two-step relay selection scheme TRS and obtain the optimal solution of the system confidentiality interruption probability through the two-step relay selection scheme.

[0061] Another object of the present invention is to provide a computer device, the computer device comprising a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0062] In the case of eavesdropping at the source node and the relay, a design is made to use the near user node as a relay node to forward information to the far user node, and a two-step relay selection scheme is designed. Through the two-step relay selection scheme, the optimal solution for the system confidentiality interruption probability is obtained.

[0063] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the following steps:

[0064] In the case of eavesdropping at the source node and the relay, a design is made to use the near user node as a relay node to forward information to the far user node, and a two-step relay selection scheme is designed. Through the two-step relay selection scheme, the optimal solution for the system confidentiality interruption probability is obtained.

[0065] Another object of the present invention is to provide an information data processing terminal, which is used to implement the physical layer security control system.

[0066] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0067] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving the problems, the technical solutions to be protected by the present invention and the results and data during the research and development process are closely combined to analyze in detail and deeply how the technical solutions of the present invention solve the technical problems, and some creative technical effects brought about after solving the problems. The specific description is as follows:

[0068] The present invention takes physical layer security as the starting point, studies the confidentiality transmission scheme of the relay cooperative communication system, and explores feasible methods to improve the reliable communication of the system.

[0069] The present invention considers the eavesdropping of the source node and the relay at the same time, designs a two-step relay selection scheme to use the near user node as a relay node to forward information to the far user node, and maximizes the data rate of the near user information transmission while ensuring the reliable transmission of the far user information.

[0070] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0071] The physical layer security control method provided by the present invention can obtain better confidentiality and security performance, and obtains the optimal solution of the system confidentiality interruption probability through a two-step relay selection scheme. Compared with the traditional random relay selection scheme, better confidentiality and security performance can be obtained.

[0072] Third, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0073] The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0074] It fills the research gap of physical layer security performance in the scenario where the nearby user acts as a relay, and studies the confidentiality interruption probability performance in this scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0076] Figure 1 It is a flow chart of the physical layer security control method provided by an embodiment of the present invention.

[0077] Figure 2 It is a structural block diagram of a physical layer security control system provided by an embodiment of the present invention.

[0078] Figure 3It is a schematic diagram of a system model provided by an embodiment of the present invention.

[0079] Figure 4 It is a SOP comparison diagram of NOMA-TRS, NOMA-RRS and OMA-RRS provided in an embodiment of the present invention.

[0080] Figure 5 It is a SOP comparison diagram of NOMA-TRS and NOMA-RRS when N=2, 3, and 4 provided in an embodiment of the present invention.

[0081] Figure 6 It is a SOP comparison diagram of NOMA-TRS when the values ​​of R1 and R2 provided in the embodiment of the present invention are different.

[0082] Figure 7 It is a SOP comparison chart of NOMA-TRS and NOMA-RRS when a1 values ​​provided in an embodiment of the present invention are different.

[0083] In the figure: 1. System model building module; 2. Transmission process determination module; 3. Optimal solution determination module. DETAILED DESCRIPTION

[0084] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0085] In view of the problems existing in the prior art, the present invention provides a physical layer security control method, system, medium, device and terminal. The present invention is described in detail below with reference to the accompanying drawings.

[0086] 1. Explanatory Examples In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an illustrative example that expands and describes the technical solution of the claims.

[0087] like Figure 1 As shown, the physical layer security control method provided by the embodiment of the present invention includes the following steps:

[0088] S101, build system model;

[0089] S102, determining a transmission process based on the system model;

[0090] S103, designing a two-step relay selection scheme TRS, and obtaining an optimal solution for the system confidentiality interruption probability through the two-step relay selection scheme.

[0091] like Figure 2 As shown, the physical layer security control system provided by the embodiment of the present invention includes:

[0092] System model building module 1, used to build a system model;

[0093] A transmission process determination module 2, used to determine the transmission process based on the system model;

[0094] The optimal solution determination module 3 is used to design a two-step relay selection scheme TRS, and obtain the optimal solution of the system confidentiality interruption probability through the two-step relay selection scheme.

[0095] The physical layer security technology based on the collaborative NOMA system provided by the embodiment of the present invention is based on Figure 3 As shown, it includes a source node BS, N trusted DF relay nodes R1…R N , a remote user node D, and an illegal eavesdropper Eve. n Nodes and D-nodes have different data rate requirements. n The node needs a higher data rate to complete the transmission of confidential messages with large data volume, such as videos, while the D node needs a lower data rate to complete the transmission of confidential messages with small data volume, such as simple text. n , D's QoS requirements, R n , D are divided into near users and far users respectively. All nodes in the model are equipped with a single antenna, and relays R1…R N It works in half-duplex and DF mode. Considering the deep fading or obstacles caused by long-distance transmission, there is no direct link between the source node and the remote user node, and normal communication can only be completed through relay-assisted forwarding. The eavesdropper is located between the source node and the destination node and can eavesdrop on the messages sent by the source node and the relay at the same time.

[0096] make Represents BS to R n , R n to D, BS to Eve, R n To Eve's channel coefficient. All channels obey the complex Gaussian distribution, that is The noise at all nodes in the model is additive white Gaussian noise.

[0097] like Figure 3 In the model shown, the transmission process is divided into two stages. In the first stage, the source node S sends the superposition message of x1 and x2 in the form of NOMA. In the first stage, the relay R1…R N , the messages Eve receives are:

[0098]

[0099]

[0100] Among them, P S is the power of the signal sent by the source node, α1 and α2 are NOMA power allocation factors and satisfy α1>α2, α1+α2=1. n SE are the AWGN at the relay and the eavesdropper, respectively, with a mean of 0 and a variance of

[0101] The serial interference cancellation technology in NOMA technology is used to decode information x1 and x2 respectively. Because the relay has a better channel gain, the relay first uses information x2 as interference to decode information x1 and then decodes its own information:

[0102]

[0103]

[0104] Under this model, considering the worst case, it is assumed that Eve has multi-user detection capability, that is, parallel interference cancellation (PIC) can be used at the Eve node to decode the aliased signal. Therefore, the signal-to-noise ratios of x1 and x2 decoded at Eve in the first stage are:

[0105]

[0106]

[0107] In the second stage, a relay will be selected as a cooperative forwarding node, and the DF protocol will be used for forwarding. The signal received by the remote user is:

[0108]

[0109] Among them, P R is the transmit power of the relay node. is the noise at the relay node, with a mean of 0 and a variance of Then the SINR of the decoded information x1 at the far user D is:

[0110]

[0111] in, At the same time, the SINR of the decoded information x1 at the eavesdropper is:

[0112]

[0113] in,

[0114] Combining the above two stages, according to the calculation formula of safety capacity, the capacity of information x1 and x2 can be obtained as follows:

[0115]

[0116]

[0117] in, is the spectral efficiency factor.

[0118] For the eavesdropping link, the eavesdropper combines the signals of the two stages and can obtain the capacities of information x1 and x2 at the eavesdropping link respectively:

[0119]

[0120]

[0121] Then the confidentiality capacity of information x1 and x2 is:

[0122]

[0123]

[0124] Where [x] + =max{x,0}.

[0125] According to the above results, the present invention designs a two-stage relay selection scheme (Two-Stage Relay Selection, TRS) as the research content, and provides an optimal relay selection scheme (Optimal Relay Selection, ORS) and a random relay selection scheme (Random Selection, RRS) as comparison schemes.

[0126] The two-step relay selection scheme consists of two stages, aiming to ensure the successful transmission of the base station-far user link while maximizing the confidentiality rate of the base station-near user link. In the first stage, a relay subset Sr is selected, in which all relays can guarantee the successful transmission of the far user. The specific expression is as follows:

[0127]

[0128] in, is the target rate of far user D.

[0129] Next, a relay is selected in Sr to maximize the confidentiality capacity of the near user information x2:

[0130]

[0131] Figure 4 The confidentiality outage probabilities under three schemes are included, namely NOMA-TRS, NOMA-RRS, and OMA-RRS. and The curve distribution represents the simulated values ​​of outage probabilities of OMA-RRS and NOMA-RRS. and The curves are the theoretical values ​​and simulation values ​​under the NOMA-RRS scheme. In this figure, the present invention first observes the exact match between the analytical expression of the exact SOP and the simulation, which proves the correctness of the precise analysis of the present invention. Secondly, it can be seen that under the same signal-to-noise ratio, the confidentiality interruption probability of the NOMA-RRS scheme is less than that of NOMA-RRS and OMA-RRS, and the confidentiality performance is better than the two schemes.

[0132] Figure 5 The main purpose is to compare the impact of the number of relays on the probability of confidentiality interruption in the multi-relay NOMA system. It can be seen that the probability of confidentiality interruption decreases significantly when the number of relays increases. This is because when the number of relays increases, the subset of optional relays in the system becomes larger, and the probability of secure message transmission becomes greater, which causes the probability of confidentiality interruption to decrease. It is not difficult to infer that when the number of relays is large enough, the probability of confidentiality interruption will be very small, and the confidentiality performance of the entire multi-relay NOMA system will get better and better. For the random relay selection scheme, the change in the number of relays has no effect on the probability of confidentiality interruption in the system, and the same result is always maintained.

[0133] Figure 6 The main purpose is to compare the impact of R1 and R2 values ​​on the probability of confidentiality interruption in multi-relay NOMA systems. and When the value becomes smaller, the probability of system confidentiality interruption will also decrease significantly. As the target rate value decreases, these two solutions provide better interruption performance.

[0134] Figure 7 The SOP of TRS and RRS schemes under α1 = 0.9 and α2 = 0.1 are better than those under α1 = 0.8 and α2 = 0.2, respectively. Therefore, the power distribution coefficient has a great impact on the security performance. It is worth noting that the SOP is saturated in high SNR, and the target confidentiality rate of the legitimate user D1 can determine its lower performance. The main reason for this phenomenon is that the NOMA protocol limits the available data rate of the weak user D1.

[0135] 2. Application Examples: In order to prove the creativity and technical value of the technical solution of the present invention, this section provides application examples of the technical solution of the claims on specific products or related technologies.

[0136] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0137] 3. Evidence of the effects of the embodiments. The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the prior art. The following content is described in conjunction with the data, charts, etc. of the test process.

[0138] The two-step relay selection scheme designed in the above scheme can greatly improve the confidentiality interruption performance of the system, and has a lower confidentiality interruption probability than the traditional random relay selection scheme. Compared with the optimal relay selection scheme, the confidentiality interruption performance is almost the same, but the above scheme can achieve the required confidentiality interruption performance for users with different QoS requirements.

[0139] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A physical layer security control method, characterized in that: The following steps are involved: Step 1: Build a system model; Step 2: determining a transmission process based on the system model; Step 3: Design a two-step relay selection scheme TRS, and obtain the optimal solution of the system confidentiality interruption probability through the two-step relay selection scheme; The system model in step 1 includes a source node BS, N trusted DF relay nodes R1…R N , a remote user node D, and an illegal eavesdropper Eve; R n Nodes and D-nodes have different data rate requirements. n The node needs a higher data rate to complete the transmission of confidential messages with large data volume, and the D node needs a lower data rate to complete the transmission of confidential messages with small data volume. n , D's QoS requirements, R n , D are divided into near users and far users respectively; all nodes in the model are equipped with a single antenna, and relays R1…R N Works in half-duplex, DF mode; Considering the deep fading or obstacles caused by long-distance transmission, there is no direct link between the source node and the remote user node, and normal communication can only be completed through relay-assisted forwarding; the eavesdropper is located between the source node and the destination node and can eavesdrop on the messages sent by the source node and the relay at the same time; make h SE , Represents BS to R n , R n to D, BS to Eve, R n to Eve’s channel coefficients; all channels obey complex Gaussian distribution, The noise at all nodes in the model is additive Gaussian white noise; The transmission process in step 2 is divided into two stages, specifically including: In the first stage, the source node S sends the superposition message of x1 and x2 in the form of NOMA. In the first stage, in the relay R1…R N , the messages Eve receives are: Among them, P S is the power of the signal sent by the source node, a1 and a2 are NOMA power allocation factors and satisfy a1>a2, a1+a2=1; n SE They are AWGN at the relay and the eavesdropper respectively; The serial interference cancellation technology in NOMA technology is used to decode information x1 and x2 respectively. The relay first uses information x2 as interference to decode information x1 and then decodes its own information: Under the system model, when Eve has multi-user detection capability, parallel interference elimination PIC is used to decode aliased signals at the Eve node. Therefore, the signal-to-noise ratios of x1 and x2 decoded at Eve in the first stage are: In the second stage, a relay is selected as a cooperative forwarding node and the DF protocol is used for forwarding. The signal received by the remote user is: Among them, P R is the transmit power of the relay node; is the noise at the relay node, with a mean of 0 and a variance of Then the SINR of the decoded information x1 at the far user D is: in, The SINR of the decoded information x1 at the eavesdropper is: in, Combining the two stages, the capacity of information x1 and x2 is obtained according to the calculation formula of safety capacity: in, is the spectrum efficiency factor; For the eavesdropping link, the eavesdropper combines the signals of the two stages and obtains the capacities of information x1 and x2 at the eavesdropping link respectively: Then the confidentiality capacity of information x1 and x2 is: Where [x] + =max{x,0}; In step 3, a two-step relay selection scheme TRS is designed as the analysis content. The two-step relay selection scheme includes two stages, which are used to ensure the successful transmission of the base station-far user link while maximizing the confidentiality rate of the base station-near user link; In the first stage, a relay subset Sr is selected, in which all relays can guarantee the successful transmission of the remote user, which is expressed as follows: in, is the target rate of far user D; In the second stage, a relay is selected from Sr to maximize the confidentiality capacity of the near user information x2:

2. A physical layer security control system using the physical layer security control method according to claim 1, characterized in that: The physical layer security control system comprises: System model building module, used to build system model; A transmission process determination module, used for determining the transmission process based on the system model; The optimal solution determination module is used to design a two-step relay selection scheme TRS and obtain the optimal solution of the system confidentiality interruption probability through the two-step relay selection scheme.

3. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the physical layer security control method according to claim 1.

4. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the physical layer security control method according to claim 1.

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