Interferer-assisted hidden rate splitting multiple access communication transmission performance calculation method

Abstract

The invention discloses a jammer-assisted hidden rate splitting multiple access communication transmission performance calculation method, which comprises the following steps of: firstly, constructing a downlink jammer-assisted hidden rate splitting multiple access communication network system, and pre-coding public messages and private messages by a transmitting end by adopting weighted maximum ratio transmission and a zero-forcing algorithm to obtain a pre-coding matrix; secondly, acquiring signal-to-interference-plus-noise ratios of K user channels, and calculating an average transmission rate of public messages and private messages in combination with the precoding matrix; finally, the average receiving power of the eavesdropping end is obtained, the sum of the false alarm probability and the false alarm probability is calculated, and the detection error probability DEP and the minimum detection error probability are obtained; and calculating a closed expression of an average minimum detection error probability under Rayleigh fading by combining channel state information. According to the method, a concealed rate splitting multiple access communication architecture is designed, the detection capability of an attack eavesdropper is limited, and the concealment of the system is verified by designing a calculation system with transmission performance.

Description

Technical Field

[0001] The invention belongs to the field of communication security, and in particular relates to a jammer-assisted concealed rate splitting multiple access communication transmission performance calculation method. Background Art

[0002] Covert communication is a wireless communication technology that can achieve a low detection probability of wireless signals at the physical layer, that is, it can achieve hidden information transmission between the communicating parties to prevent the communication signal from being discovered by malicious eavesdroppers. The shelter for hiding the signal is generally background noise or interference signals. If malicious users cannot confirm the existence of the signal, it is difficult to carry out further illegal activities. Covert communication and physical layer security technology are both effective means to ensure communication security at the physical layer, but physical layer security protects private communication content, while covert wireless communication protects more basic communication behaviors.

[0003] The characteristic of rate split multiple access (RSMA) communication is that the information of each user is split into public messages and private messages at the transmitter. The public messages of all users are combined and encoded together, while the private messages of each user are encoded independently and can only be decoded by the corresponding user. The transmitter pre-encodes the public messages and private messages and sends them to the users in the system. The user uses continuous interference cancellation technology to process the received messages, first treating all private messages as interference and decoding the public messages. After obtaining the desired public message, the user deletes the public information on the basis of the original received message, treats the private information corresponding to other users as noise, and decodes the user's own private information. It can be found that RSMA soft bridges the two extremes of fully decoding interference and treating interference completely as noise by partially decoding interference and treating part of the interference as noise. It is considered to be a bridge connecting non-orthogonal multiple access (NOMA) technology and space division multiple access (SDMA) technology. In RSMA communication, public messages can not only transmit useful data for users, but also act as interference signals to confuse eavesdroppers and improve the confidentiality of wireless communication systems. At the same time, RSMA can utilize the collaboration between base stations, user equipment or relay equipment to send and receive data through multi-path transmission, avoid multiple users competing for the same resource at the same time, improve the capacity and reliability of the system, and achieve flexible interference control.

[0004] At present, there are some scientific research results on covert NOMA communication, but covert RSMA communication has not been fully studied. Without a calculation method for the transmission performance of covert RSMA communication, it is impossible to judge the security and effectiveness of its communication network. Summary of the invention

[0005] In view of the above problems, the present invention provides a jammer-assisted concealed rate splitting multiple access communication transmission performance calculation method to meet the requirements of emerging applications such as the Internet of Vehicles for secure communication, high data rate, low latency, high reliability and wide connection. Multi-antenna information transmission requires a precoding step, and channel state information is obtained through a feedback mechanism or estimation technology. A suitable precoding algorithm is selected in combination with system requirements and a precoding matrix is ​​calculated. The transmitted signal is precoded using the precoding matrix. The receiving end performs signal processing and decoding based on the received signal and the known precoding matrix. After the precoding is completed, the transmission rate calculation can be performed. The average transmission rate of the message is calculated by obtaining the signal to interference plus noise ratio (SINR) of different channels. The calculation of the average minimum detection error probability (AMDEP) requires first obtaining the precoding matrix and channel statistical characteristics. The concealed RSMA communication system judges the transmission performance of the communication network by the average transmission rate and the average minimum detection error probability.

[0006] The technical solution adopted by this patent application to solve its technical problem is:

[0007] In order to solve the above technical problems, the present invention provides a jammer-assisted concealed rate splitting multiple access communication transmission performance calculation method. The performance calculation method comprises the following steps:

[0008] Step 1: Construct a downlink jammer-assisted concealed rate splitting multiple access communication network system model. The communication network includes a jammer, a t A transmitter with 1 antenna, K users and an eavesdropper. To ensure normal communication, the number of users does not exceed the number of antennas on the transmitter. The transmitter sends a public message and K private messages to K users in a wireless communication environment. The eavesdropper needs to detect whether there is any private message transmission between the transmitter and the user. The jammer continues to send jamming messages to the eavesdropper. Since the jammer is controllable, it can be assumed that the jammer has no jamming effect on the user. At the same time, the transmitter will continue to send public messages to increase the probability of detection errors on the eavesdropper.

[0009] Step 2: Precoding step at the transmitting end: The transmitting end uses the weighted maximum ratio transmission technology (Maximum Ratio Transmission) and the zero forcing algorithm (zero forcing) to precode the public message and the private message to obtain a precoding matrix. The processing steps are as follows:

[0010] Step 2.1: Use weighted maximum ratio transmission technology to precode the public message, that is, p c =h A , where p c represents the precoding of the public message, h A is the sum of the fading coefficient vectors of all user channels.

[0011] Step 2.2: Use the zero-forcing algorithm to precode the private message to obtain H T P p =I. Among them, H T H = [h1, h2, ... h K ]The transpose of the matrix, h1, h2, ...h K are the K channels between the transmitter and K users; P p =[p1, p2, .., p K ] is H T The right Moore-Penrose pseudo-inverse matrix, p1, p2, .., p K denote the precoding on K channels respectively; I is the unit matrix; the precoding matrix P = [p c , p1, p2, …, p K ].

[0012] Step 3: Obtain the signal to interference plus noise ratio SINR of K user channels, and calculate the average transmission rate of public messages and private messages in combination with the precoding matrix. In a wireless communication environment, the channel is changing all the time. Generally, after obtaining the channel state information (CSI) through channel estimation, the channel statistical characteristics are extracted to describe the fading characteristics of the channel. For the convenience of explanation, the present invention assumes that all channels experience Rayleigh fading.

[0013] The signal to interference plus noise ratio (SINR) of K channels is obtained, and the average transmission rate of public messages and private messages is calculated in combination with the precoding matrix. The processing steps are as follows:

[0014] Step 3.1: The SINR of the public message at user k is:

[0015]

[0016] The SINR of the private message at user k is:

[0017] Among them, α c and α k denote the power allocation coefficients allocated to public messages and private messages at user k respectively; α j represents the power allocation coefficient on the channel between user j and the transmitter; P A Indicates the transmit power of the transmitter; are the path losses between user k and the transmitter, and between the user and the jammer, respectively; α j represents the power allocation coefficient on the channel between user j and the transmitter; p c and p k They represent the codes of public and private messages of user k respectively; pj represents the coding on the channel between user j and the transmitter; is the fading coefficient vector between the transmitter and user k; represents the fading coefficient vector on the channel between user j and the transmitter; is the noise variance; j is the count variable.

[0018] Step 3.2: Set the SINR of the public message to the minimum SINR among K users, that is, the SINR of the public message is Combined with the precoding matrix, the average transmission rates of public messages and private messages at user k are expressed as: and Where B is the bandwidth, Represents the mathematical expectation calculation function. The average transmission rate can be obtained as a performance indicator for evaluating the effectiveness of communication network transmission. Under the condition of ensuring the normal communication behavior of users (the transmission rate of private messages is not lower than the set range), the transmission power allocated to public messages is increased to improve the communication security of private messages.

[0019] Step 4: Calculation of the average minimum detection error probability. Obtain the average received power of the eavesdropping end to calculate the sum of the false alarm probability and the false alarm probability to obtain the detection error probability DEP; then minimize the detection threshold of DEP to obtain the minimum detection error probability MDEP; finally, combine the channel state information obtained from the channel statistical characteristics to calculate the closed-form expression of the average minimum detection error probability AMDEP under Rayleigh fading. The processing steps are as follows:

[0020] Step 4.1: Evaluate two hypotheses to determine whether the transmitter is sending a message to the user. Set the null hypothesis H0 to indicate that the transmitter is not sending private information to the user, and the alternative hypothesis H1 to indicate that the transmitter is sending private information to the user. The average received power P of the eavesdropper under the two hypotheses is W They are: and Where P J is the transmit power of the jammer, represents additive white Gaussian noise, and are the path losses between the eavesdropping end and the jammer / transmitter, respectively. JW and Represent the fading coefficient / vector between the eavesdropping end and the jammer / transmitter respectively.

[0021] Step 4.2: DEP is used to evaluate the effectiveness of the Willy hypothesis test. The performance of DEP can be expressed by the sum of the false alarm probability and the false alarm probability. The false alarm probability represents the probability that the eavesdropper judges that there is a private message communication behavior but there is no such behavior in reality, and the false alarm probability represents the probability that the eavesdropper judges that there is no private message communication behavior but there is such behavior in reality. Then the false alarm probability can be obtained from the null hypothesis and the alternative hypothesis and false alarm probability They are:

[0022] Where τ is the detection threshold and Pr(·) represents the probability calculation function.

[0023] Step 4.3: The jammer power is generally variable, and its probability distribution can be controlled to increase the probability of false detection by the eavesdropping end while reducing the impact on normal communication. The internal distribution is uniform, where is the maximum interference power.

[0024] Step 4.4: The minimum DEP (MDEP) of the eavesdropping end needs to be discussed in different situations. Greater than When MDEP is In other cases, MDEP is 0.

[0025] Step 4.5: Control the jammer power within the range The internal distribution is uniform, where is the maximum interference power, when Greater than When MDEP is In other cases, MDEP is 0;

[0026] Step 4.4: The average minimum DEP of the eavesdropping end is AMDEP. When MDEP is 0, AMDEP is 0; when MDEP is not zero, AMDEP is expressed as: That is, the product of probability and mathematical expectation, where Calculated in, N t is the number of transmitting antennas; similarly Using the Chebyshev-Gauss quadrature method, we get Where n is the number of nodes of the Chebyshev-Gauss quadrature method, is the weight, but Thus, the average minimum detection error probability of the eavesdropping end can be obtained as a performance indicator for verifying the concealment of the covert rate splitting multiple access communication network system. The larger the average minimum detection error probability of the eavesdropping end, the more secure the communication system is.

[0027] Advantages or beneficial effects of this application:

[0028] Based on the above, the present invention applies covert communication to a rate split multiple access (RSMA) network, in which the authorized sender sends public and private messages to the user. At the same time, the eavesdropper aims to identify the transmission of private messages. We exploit the properties of RSMA to allocate higher power to public messages, hide the existence of private message transmissions from the eavesdropper, and use friendly jammers to further limit the detection ability of the attacking eavesdropper. At the same time, the performance of the system is evaluated and a closed-form expression for the minimum probability of detection error is derived, which verifies the correctness of the theory and proves the concealment of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 for the invention flow chart;

[0030] Figure 2 This is a model diagram of the urban intelligent transportation scenario;

[0031] FIG3( a ) is a graph showing the relationship between AMDEP and transmit power;

[0032] FIG3( b ) is a graph showing the relationship between AMDEP and interference power;

[0033] Figure 4 is the relationship diagram between ergodic rate and transmission power;

[0034] Figure 5(a) is an experimental diagram of the relationship between AMDEP and total power;

[0035] Figure 5(b) is an experimental diagram of the relationship between ergodic rate and total power. DETAILED DESCRIPTION

[0036] The following is a detailed description of a method for calculating the transmission performance of a jammer-assisted concealed rate splitting multiple access communication in conjunction with the accompanying drawings. The specific process is as follows: Figure 1 shown.

[0037] In the scenario of urban intelligent transportation, a downlink jammer-assisted concealed rate splitting multiple access communication network is constructed. The communication network includes a jammer, a transmitter, three users and an attacker. The base station sends public messages and private messages to the user. The attacker focuses on whether there is any private message transmission between the base station and the user, and does not pay attention to the transmission and content of public messages. The jammer is friendly and controllable, that is, the jammer only considers the interference to the attack channel, and does not consider the interference of the jammer to the user. Figure 2The following is a model diagram of the urban intelligent transportation scenario. A downlink jammer-assisted concealed rate split multiple access communication network is constructed in the urban intelligent transportation scenario, including a transmitter, three users, and a friendly and controllable jammer located near the transmitter. The transmitter sends messages to the users through the channel, including one public message and three private messages. The attacker aims to detect the transmission of any private message between the transmitter and the user by monitoring the signal. In addition to using the transmission of public messages to hide the transmission of private messages, a jammer is also used to send interference signals to the attacker to reduce the probability of successful interception.

[0038] The message to be sent by the sender is set to s(l) = [s c (l),s1(l),...,s K (l)] T , where the public message is s c (l), and user U k The private message is encoded as s k (l), and Weighted Maximum Ratio Transmission (MRT) and ZF (Zero Forcing) are used to precode public and private messages. The precoding matrix P' obtained after normalization is used to precode the message at the sender: in represents the power matrix, α c =0.95 and denote the power allocation coefficients allocated to public messages and private messages, respectively.

[0039] Assuming that all channels experience Rayleigh fading, user U k The average transmission rate of public messages is expressed as: The average transmission rate of private messages is expressed as: For the convenience of demonstration, the bandwidth is set to B = 1MHz; P A and P J Represent the transmission power of the transmitter and the jammer respectively; are the path losses between the user and the transmitter / jammer, respectively, and is the fading coefficient vector between the transmitter and the user, h s is the sum of all user channels; represents the noise variance. k ′ is the normalized user U k The corresponding precoding vector. Change the transmit power P of the transmitter A , observe P A Average transfer rate and The relationship between them can be used to determine the transmission effectiveness of the communication network.

[0040] The experiment was simulated using MATLAB. The curve values ​​are theoretical values, and the circles are simulated values. A There is a positive correlation between them. Figure 3(a) shows the relationship between AMDEP and the transmit power of the transmitter, where the fixed transmit power limit of the jammer is 10dBm. Figure 3(b) shows the relationship between AMDEP and the transmit power of the jammer, where the fixed transmit power of the transmitter is 10dBm. A Decrease, when P A As P approaches infinity, it approaches 0, as shown in Figure 3(a). J As increases, AMDEP rises and approaches 1 at infinity, as shown in Figure 3(b). The above phenomenon is reasonable because the higher the ratio of interference power to public signal transmission power, the greater the uncertainty of the attacker. In addition, in both sub-figures, it can be noticed that the simulation values ​​are close to the theoretical values, which is caused by the normal error introduced by Chebyshev-Gauss quadrature.

[0041] The average minimum detection error probability (AMDEP) is Among them, N t is the number of antennas, n is the number of nodes in the Chebyshev-Gauss quadrature method, is the weight, Change the transmit power P of the transmitter A / Maximum jammer power observe The relationship between the average minimum detection error probability and the security of the communication network is judged.

[0042] Figure 4 The relationship between the ergodic rate and the transmission power is shown in Figure 1. The experiment was simulated using MATLAB, and the graph depicts the relationship between the average transmission rate (ergodic rate) of public and private messages and the transmission power of the transmitter. The average transmission rate of public messages increases with the transmission power P. A increases with the increase of P and eventually converges to a certain value. On the other hand, the average transmission of private messages increases with the increase of P A This also shows that the transmission of private messages is more worthy of protection and concealment.

[0043] The experiment was simulated using MATLAB. Figure 5(a) and Figure 5(b) show the total power AMDEP and ergodic rate under this condition, the transmit power is numerically equal to the interference power It is noteworthy that AMDEP is not affected by P AJThe influence of , which affects the individual and overall traversal rates. In addition, in this case, the approximation error of AMDEP is negligible, and AMDEP can reach 85%, indicating that the covert communication effect is good and the communication system has strong security.

Claims

1. A jammer-assisted concealed rate splitting multiple access communication transmission performance calculation method, characterized in that: The following steps are involved: Step 1: Construct a downlink jammer-assisted concealed rate split multiple access communication network system, which includes a jammer, a t A transmitter with root antennas, K users and an eavesdropper; Step 2: The transmitter uses weighted maximum ratio transmission technology and zero forcing algorithm to precode the public message and the private message to obtain a precoding matrix; Step 3: Obtain the signal to interference plus noise ratio (SINR) of K user channels, calculate the average transmission rate of public messages and private messages in combination with the precoding matrix, and evaluate the transmission performance of the communication network; Step 4: Obtain the average receiving power of the eavesdropping end and calculate the sum of the false alarm probability and the false alarm probability to obtain the detection error probability DEP; then minimize the detection threshold of DEP to obtain the minimum detection error probability MDEP; finally, combine the channel state information obtained from the channel statistical characteristics to calculate the closed-form expression of the average minimum detection error probability AMDEP under Rayleigh fading to verify the concealment of the concealed rate splitting multiple access communication network system.

2. According to claim 1, a jammer-assisted concealed rate splitting multiple access communication transmission performance calculation method is characterized in that: The number of users in the concealed rate splitting multiple access communication network system does not exceed the number of antennas at the transmitting end; the transmitting end sends a public message and K private messages to K users in a wireless communication environment; the eavesdropping end detects whether there is a transmission of private messages between the transmitting end and the user; The jammer continuously sends jamming messages to the eavesdropping end; the jammer is controllable, and does not produce jamming effects on users. The transmitting end continuously sends public messages, increasing the probability of detection errors of the eavesdropping end.

3. The method for calculating the transmission performance of a jammer-assisted concealed rate splitting multiple access communication according to claim 2, characterized in that: The specific implementation process of step 2 is as follows: Step 2.1: Use weighted maximum ratio transmission technology to precode the public message, that is, p c =h A , where p c represents the precoding of the public message, h A is the sum of the fading coefficient vectors of all user channels; Step 2.2: Use the zero-forcing algorithm to precode the private message to obtain H T P p =I; where H T H = [h1, h2, ... h K ]The transpose of the matrix, h1,h2,…h K are the fading coefficient vectors of the K channels between the transmitter and the K users; P p =[p1,p2,…,p K ] is H T The right Moore-Penrose pseudo-inverse matrix, p1,p2,…,p K denote the precoding on K channels respectively; I is the unit matrix; thus, the precoding matrix P = [p c , p1, p2, …, p K ].

4. The method for calculating the transmission performance of a jammer-assisted concealed rate splitting multiple access communication according to claim 3, characterized in that: The specific implementation process of step 3 is as follows: Step 3.1: The SINR of the public message at user k is: The SINR of the private message at user k is: Among them, α c and α k denote the power allocation coefficients allocated to public messages and private messages at user k respectively; α j represents the power allocation coefficient on the channel between user j and the transmitter; P A Indicates the transmit power of the transmitter; are the path losses between user k and the transmitter, and between the user and the jammer, respectively; α j represents the power allocation coefficient on the channel between user j and the transmitter; p c and p k They represent the codes of public and private messages of user k respectively; p j represents the coding on the channel between user j and the transmitter; is the fading coefficient vector between the transmitter and user k; represents the fading coefficient vector on the channel between user j and the transmitter; is the noise variance; j is the count variable; Step 3.2: Set the SINR of the public message to the minimum SINR among K users, that is, the SINR of the public message is Combined with the precoding matrix P, the average transmission rates of public messages and private messages at user k are expressed as: and Where B is the bandwidth, Represents the mathematical expectation calculation function.

5. The method for calculating the transmission performance of a jammer-assisted concealed rate splitting multiple access communication according to claim 4, characterized in that: The specific implementation process of step 4 is as follows: Step 4.1: Set the null hypothesis H0 to indicate that the transmitter does not send private information to the user, and the alternative hypothesis H1 to indicate that the transmitter sends private information to the user; the average received power P of the eavesdropper under the two hypotheses is W They are and P J is the transmit power of the jammer; represents additive white Gaussian noise, and are the path losses between the eavesdropping end and the jammer / transmitter respectively; h JW and Represent the fading coefficient / vector between the eavesdropping end and the jammer / transmitter respectively; Step 4.2: The performance of DEP is represented by the sum of the false alarm probability and the false alarm probability; the false alarm probability is obtained from the null hypothesis and the alternative hypothesis and false alarm probability They are: Among them, τ is the detection threshold, Pr(·) represents the probability calculation function; Step 4.3: Control the jammer power within the range The internal distribution is uniform, where is the maximum interference power, when Greater than When MDEP is In other cases, MDEP is 0; Step 4.4: The average minimum DEP of the eavesdropping end is AMDEP. When MDEP is 0, AMDEP is 0; when MDEP is not zero, AMDEP is expressed as: That is, the product of probability and mathematical expectation, where Calculated in, N t is the number of transmitting antennas; similarly Using the Chebyshev-Gauss quadrature method, we get Where n is the number of nodes of the Chebyshev-Gauss quadrature method, is the weight, but

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