Method for friendly interference assisted information transmission in omni-directional reconfigurable intelligent surface network

Abstract

A kind of simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) network friendly interference assisted information transmission method is composed of steps of constructing transmission signal model, establishing channel model, deducing average minimum detection error probability, analyzing transmission interruption probability and hidden throughput, determining secret interruption probability. The present application adopts the reflection and transmission dual functions of STAR-RIS, combined with the construction of transmission architecture for non-orthogonal multiple access of friendly interference technology, and proposes a friendly interference assisted information transmission method. The method constructs independent transmission channels for hidden users and secure users through STAR-RIS, and cooperates with the friendly interference mechanism to improve the detection error probability of the monitor, effectively avoiding the communication process from being identified. By determining the secret interruption probability, the risk of intercepting information by the eavesdropper is reduced, and the confidentiality of data is ensured. At the same time, with the help of power allocation strategy, the channel differences of multiple users are balanced, the transmission interruption probability is controlled within the preset threshold, and the transmission stability and hidden throughput are significantly improved. The present application has the advantages of reasonable transmission design, easy implementation, excellent concealment performance, good security effect, reliable transmission and high throughput, and can be used in the field of wireless communication technology.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a joint covert communication and physical layer secure transmission technology with friendly interference assistance in omnidirectional reconfigurable smart surface networks. It is applicable to scenarios in next-generation wireless communication networks where there are high requirements for the covertness, confidentiality and reliability of information transmission. Background Technology

[0002] In recent years, with the rapid development of 6G wireless systems and the Internet of Things (IoT), next-generation communication networks need to support unprecedented connectivity demands while significantly improving spectrum efficiency. Non-Orthogonal Multiple Access (NOMA) technology, as a key enabling technology for next-generation communication, utilizes the core principles of superposition coding at the transmitter and successive interference cancellation (SIC) at the receiver to provide services to multiple users simultaneously. Compared to traditional orthogonal transmission schemes, it boasts superior spectrum efficiency and massive connectivity capabilities, and has become a core foundation supporting the development of 6G networks.

[0003] Reconfigurable Intelligent Surfaces (RIS), a revolutionary technology for 6G networks, can significantly improve channel conditions by dynamically adjusting the wireless propagation environment through software-controlled metasurfaces. However, most existing studies assume that the transmitter and receiver must be located on the same side of the RIS, a geographical limitation that severely restricts the flexibility and effectiveness of RIS deployment. To overcome this coverage bottleneck, STAR-RIS has emerged, which can simultaneously provide services to users on both the same and opposite sides of the source end by reflecting and refracting signals, greatly expanding application scenarios.

[0004] With the rapid development of wireless communication, information security and privacy protection have become core requirements that cannot be ignored. Physical layer security technology utilizes the fading characteristics and noise uncertainty of wireless channels to resist illegal interception by eavesdroppers without relying on encryption protocols; while covert communication technology further hides the transmitted signal in environmental noise or regular communication traffic by designing effective transmission mechanisms, avoiding detection of the communication behavior itself by the monitor, and providing a deeper level of protection for communication privacy.

[0005] However, existing technologies still have many problems that urgently need to be solved: On the one hand, in systems combining STAR-RIS and NOMA, there is a lack of design for joint covert communication and physical layer security. Most solutions only focus on one of the performance aspects, making it difficult to simultaneously meet the requirements of covertness and confidentiality. On the other hand, friendly interference, as a key means of enhancing covertness, has not been effectively integrated into the STAR-RIS-assisted NOMA framework, making it difficult to effectively suppress the detection accuracy of the monitor. In addition, existing research either uses a simplified RIS model or ignores the complexity of multi-user scenarios, lacking a comprehensive design that simultaneously ensures the system's covertness, confidentiality, and reliability under actual transmission protocols.

[0006] Therefore, in STAR-RIS-assisted NOMA systems, how to integrate friendly jamming techniques, design a transmission scheme that combines covert communication and physical layer security, and simultaneously meet the quality of service requirements of multiple users has become a pressing technical challenge in the field of wireless communication. Summary of the Invention

[0007] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies, such as the difficulty in coordinating covert communication and physical layer security, significant interference in multi-user transmission, and insufficient transmission reliability due to channel fading. This invention provides a method for information transmission in omnidirectional reconfigurable smart surface networks with friendly interference assistance. This method leverages the signal reflection gain enhancement capability of STAR-RIS, combined with friendly interference strategies and NOMA multi-user scheduling mechanisms, to achieve a transmission effect that meets concealment requirements, controllable security performance, high system throughput, and strong robustness. It also features a simple transmission process, ease of engineering implementation, and adaptability to complex wireless channel environments.

[0008] The technical solution adopted to solve the above technical problems consists of the following steps: (1) Constructing a transmission signal model The transmission system model consists of one transmitter (Alice), one friendly jammer (Jammer), one STAR-RIS, one monitor (Willie), one eavesdropper (Eve), one covert user (Bob), and one secure user (Carl). STAR-RIS includes... Each reflective element and Each of the transmitter, user, monitor, and eavesdropper is equipped with a single antenna, which serves as a transmission element. The transmitter establishes a communication link with the covert user through the reflection function of STAR-RIS and with the confidential user through the transmission function. Friendly jammers are deployed near the transmitter, thus completing the transmission system model.

[0009] (2) Establish a channel model Friendly jammers emit artificial noise; jamming power obey The probability density function of the uniform distribution in the interval is: (1) in, This is the maximum power given by the jammer, with a value of 10dBm.

[0010] All wireless channels exhibit Rayleigh fading characteristics, and the channel coefficients of each link (i.e., Alice / Jammer→STAR-RIS and STAR-RIS→Bob / Willie / Carl / Eve links) follow a complex Gaussian distribution with a mean of 0 and a variance of 1. ,in .

[0011] (3) Derive the average minimum detection error probability The average minimum detection error probability of the monitor is derived according to equation (2): (2) in, It is the distance from the transmitter to STAR-RIS. This refers to the distance from the jammer to STAR-RIS; both values ​​are set to 100m. It is the path loss function. This is the path loss factor, with a value of 2.5. This is the transmit power that Alice, the transmitter, allocates to the covert user Bob, with a value of 10 dBm.

[0012] (4) Analyze user interruption probability and hidden throughput Determine the interruption probability of the covert user Bob according to formula (3): (3)

[0013]

[0014] in, It is the signal-to-interference-plus-noise ratio (SIR) of decoding the signal from the secure user Carl at the location of the covert user Bob. It is the signal-to-interference-plus-noise ratio (SIR) of the covert user Bob decoding his own signal. and These are the preset data transmission rates from the transmitter to users Bob and Carl, respectively, with values ​​of 0.2 bit / s / Hz and 0.1 bit / s / Hz. This is the reflection matrix of STAR-RIS, where , , This is the transmit power allocated by the transmitter to the secure user Carl, with a value of 40 dBm. This is the distance from STAR-RIS to the concealed user Bob, with a value of 50m. and These are the noise power at the covert user Bob and the secure user Carl, respectively, with a value of -40dBm.

[0015] The transmission interruption probability of the secure user Carl is determined according to equation (4): (4)

[0016] in, It is the signal-to-interference-plus-noise ratio (SIR) of the user Carl decoding his own signal. It is the STAR-RIS transmission matrix, and has , .

[0017] Determine the system's hidden throughput according to equation (5): (5) Determine the probability of security breach. Determine the probability of confidentiality breach for secure user Carl using equation (6): (6)

[0018] in, It refers to the signal-to-interference-plus-noise ratio (SIR) of the signal eavesdropping on the secure user Carl's signal from Eve's location. yes The corresponding probability density function, yes The corresponding cumulative distribution function, This is the noise power at Eve, the eavesdropper, with a value of -40dBm.

[0019] A method for information transmission with friendly interference assistance in omnidirectional reconfigurable smart surface networks was developed.

[0020] In step (2) of the present invention, the channel model is established. It is the maximum power given by the jammer, with a value of 10dBm. The wireless channels all follow a complex Gaussian distribution with a mean of 0 and a variance of 1.

[0021] In step (3) of the present invention, the formula (2) is described as follows: It is the path loss factor, and the optimal value is 2.5.

[0022] In formula (3) of step (4) of the present invention, and These are the preset data transmission rates for transmitter Alice to covert user Bob and secure user Carl, respectively, with values ​​of 0.2 bit / s / Hz and 0.1 bit / s / Hz. and These are the noise power at the covert user Bob and the secure user Carl, respectively, with a value of -40dBm.

[0023] In step (5) of the present invention, determining the probability of security breach, the aforementioned This is the noise power at Eve, the eavesdropper's location; the optimal value is -40dBm.

[0024] This invention employs a STAR-RIS-assisted NOMA multi-user transmission architecture, combining friendly interference strategies with physical layer security design to establish a transmission signal model that balances concealment and security. It proposes a method for information transmission that integrates covert communication and physical layer security. Under limited spectrum resources, this method enhances the quality of useful links and suppresses the impact of interfering links through the signal reflection gain of STAR-RIS. Combined with the NOMA multi-user scheduling mechanism, it achieves synergistic optimization of concealment and security performance. Compared with existing technologies, when the number of STAR-RIS reflection units is 10 and the interference power is 10 dBm, the system's covert throughput is more than 1.5 times higher than traditional transmission methods without STAR-RIS assistance. With reasonable adjustment of the friendly interference power, the system's covert throughput and secure transmission reliability are further improved. This invention has advantages such as simple transmission process, ease of engineering implementation, satisfactory concealment, controllable security performance, and strong robustness, making it suitable for covert transmission and physical layer security protection in wireless communication. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention.

[0026] Figure 2 This is the curve showing the effect of the transmitter's transmission power on the average minimum detection error probability of the monitor. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but is not limited to the following embodiments.

[0028] Example 1 exist Figure 1 In this embodiment, the information transmission method with friendly interference assistance in an omnidirectional reconfigurable smart surface network consists of the following steps: (1) Constructing a transmission signal model The transmission system model consists of one transmitter (Alice), one friendly jammer (Jammer), one STAR-RIS, one monitor (Willie), one eavesdropper (Eve), one covert user (Bob), and one secure user (Carl). STAR-RIS includes... Each reflective element and Each of the transmitter, user, monitor, and eavesdropper is equipped with a single antenna, which serves as a transmission element. The transmitter establishes a communication link with the covert user through the reflection function of STAR-RIS and with the confidential user through the transmission function. Friendly jammers are deployed near the transmitter, thus completing the transmission system model.

[0029] (2) Establish a channel model Friendly jammers emit artificial noise; jamming power obey The probability density function of the uniform distribution in the interval is: (1) in, This is the maximum power given by the jammer, with a value of 10dBm.

[0030] All wireless channels exhibit Rayleigh fading characteristics, and the channel coefficients of each link (i.e., Alice / Jammer→STAR-RIS and STAR-RIS→Bob / Willie / Carl / Eve links) follow a complex Gaussian distribution with a mean of 0 and a variance of 1. ,in .

[0031] (3) Derive the average minimum detection error probability The average minimum detection error probability of the monitor is derived according to equation (2): (2) in, It is the distance from the transmitter to STAR-RIS. This refers to the distance from the jammer to STAR-RIS; both values ​​are set to 100m. It is the path loss function. This is the path loss factor, with a value of 2.5. This is the transmit power that Alice, the transmitter, allocates to the covert user Bob, with a value of 10 dBm.

[0032] (4) Analyze user interruption probability and hidden throughput The probability of the hidden user Bob being interrupted is analyzed according to equation (3): (3)

[0033]

[0034] in, It is the signal-to-interference-plus-noise ratio (SIR) of decoding the signal from the secure user Carl at the location of the covert user Bob. It is the signal-to-interference-plus-noise ratio (SIR) of the covert user Bob decoding his own signal. and These are the preset data transmission rates from transmitter Alice to users Bob and Carl, with values ​​of 0.2 bit / s / Hz and 0.1 bit / s / Hz respectively. This is the reflection matrix of STAR-RIS, where , , This is the transmit power that transmitter Alice allocates to the secure user Carl, with a value of 10 dBm. This is the distance from STAR-RIS to the concealed user Bob, with a value of 50m. and These are the noise power at the covert user Bob and the secure user Carl, respectively, with a value of -40dBm.

[0035] The transmission interruption probability of the secure user Carl is determined according to equation (4): (4)

[0036] in, It is the signal-to-interference-plus-noise ratio (SIR) of the user Carl decoding his own signal. It is the STAR-RIS transmission matrix, and has , .

[0037] Determine the system's hidden throughput according to equation (5): (5) Determine the probability of security breach. Determine the probability of confidentiality breach for secure user Carl using equation (6): (6)

[0038] in, It refers to the signal-to-interference-plus-noise ratio (SIR) of the signal eavesdropping on the secure user Carl's signal from Eve's location. yes The corresponding probability density function, yes The corresponding cumulative distribution function, This is the noise power at Eve, the eavesdropper, with a value of -40dBm.

[0039] Because this embodiment employs a STAR-RIS-assisted NOMA multi-user transmission architecture, combined with friendly interference strategies and physical layer security design, a transmission signal model that balances concealment and security is established. A method for information transmission that integrates covert communication and physical layer security is proposed. Under limited spectrum resources, this method significantly improves the system's concealment, confidentiality, and transmission reliability through the dual reflection and transmission functions of STAR-RIS, coupled with a power allocation strategy.

[0040] To verify the beneficial effects of this invention, the inventors used the friendly interference-assisted information transmission method in the omnidirectional reconfigurable smart surface network of Embodiment 1 of this invention and conducted a comparative simulation experiment with the existing covert communication method of STAR-RIS-aided NOMA networks, "Covert communication of STAR-RIS aided NOMA networks," IEEE Transactions on Vehicular Technology, vol. 73, no. 6, pp. 9055–9060, Jun. 2024. The experimental results are shown in Figure 2. Figure 2 shows the influence curve of the transmitter's transmit power on the average minimum detection error probability of the monitor when the maximum interference power is set to 10 dBm. As shown in Figure 2, compared with the comparative experimental method, the method in Example 1 improved the average minimum detection error probability of the monitor by 0.1 to 0.4 in the range of -20dBm to 20dBm, significantly enhancing the system's stealth. In particular, when the transmission power is 5dBm, the average minimum detection error probability is improved by more than 0.4 compared with the comparative experimental method, fully verifying the optimization effect of the combination of friendly interference and STAR-RIS on the system's stealth, and further confirming the superiority of this method in improving communication stealth performance.

Claims

1. A method for information transmission with friendly interference assistance in an omnidirectional reconfigurable smart surface network, characterized in that... It consists of the following steps: (1) Constructing a transmission signal model The transmission system model consists of one transmitter (Alice), one friendly jammer (Jammer), one omnidirectional reconfigurable smart surface (STAR-RIS), one monitor (Willie), one eavesdropper (Eve), one covert user (Bob), and one secure user (Carl). STAR-RIS includes... Each reflective element and Each of the transmitter, user, monitor, and eavesdropper is equipped with a single antenna, which serves as a transmission element. The transmitter establishes a communication link with the covert user through the reflection function of STAR-RIS and with the confidential user through the transmission function. Friendly jammers are deployed near the transmitter, thus completing the transmission system model. (2) Establish a channel model Friendly jammers emit artificial noise; jamming power obey The probability density function of the uniform distribution in the interval is: （1） in, The maximum power given to the jammer is 10 dBm. All wireless channels exhibit Rayleigh fading characteristics, and the channel coefficients of each link (i.e., Alice / Jammer→STAR-RIS and STAR-RIS→Bob / Willie / Carl / Eve links) follow a complex Gaussian distribution with a mean of 0 and a variance of 1. ,in . (3) Derive the average minimum detection error probability The average minimum detection error probability of the monitor is derived according to equation (2): （2） in, It is the distance from the transmitter to STAR-RIS. This refers to the distance from the jammer to STAR-RIS; both values ​​are set to 100m. This is the path loss function. This is the path loss factor, with a value of 2.

5. This is the transmit power that Alice, the transmitter, allocates to the covert user Bob, with a value of 10 dBm. (4) Analyze the transmission interruption probability and the hidden throughput. The transmission interruption probability of the covert user Bob is determined according to equation (3): （3） in, It is the signal-to-interference-plus-noise ratio (SIR) of decoding the signal from the secure user Carl at the location of the covert user Bob. It is the signal-to-interference-plus-noise ratio (SIR) of the covert user Bob decoding his own signal. and These are the preset data transmission rates from the transmitter to users Bob and Carl, respectively, with values ​​of 0.2 bit / s / Hz and 0.1 bit / s / Hz. This is the reflection matrix of STAR-RIS, where , , This is the transmit power allocated by the transmitter to the secure user Carl, with a value of 40 dBm. This is the distance from STAR-RIS to the concealed user Bob, with a value of 50m. and These are the noise power at the covert user Bob and the secure user Carl, respectively, with a value of -40dBm. The transmission interruption probability of the secure user Carl is determined according to equation (4): （4） in, It is the signal-to-interference-plus-noise ratio (SIR) of the user Carl decoding his own signal. It is the STAR-RIS transmission matrix, and has , . Determine the system's hidden throughput according to equation (5): (5) Determine the probability of security breach. Determine the probability of confidentiality breach for secure user Carl using equation (6): （6） in, It refers to the signal-to-interference-plus-noise ratio (SIR) of the signal eavesdropping on the secure user Carl's signal from Eve's location. yes The corresponding probability density function, yes The corresponding cumulative distribution function, This is the noise power at Eve, the eavesdropper, with a value of -40dBm. A method for information transmission with friendly interference assistance in omnidirectional reconfigurable smart surface networks was developed.

2. The information transmission method with friendly interference assistance in an omnidirectional reconfigurable smart surface network according to claim 1, characterized in that: In (2) establishing the channel model, It is the maximum transmit power given by the jammer, with a value of 10dBm. The wireless channels all follow a complex Gaussian distribution with a mean of 0 and a variance of 1.

3. The information transmission method with friendly interference assistance in an omnidirectional reconfigurable smart surface network according to claim 1, characterized in that: In step (3) of equation (2), the said It is the path loss factor, with a value of 2.

5.

4. The information transmission method with friendly interference assistance in an omnidirectional reconfigurable smart surface network according to claim 1, characterized in that: In equation (3) of step (4), and These are the preset data transmission rates for transmitter Alice to covert user Bob and secure user Carl, respectively, with values ​​of 0.2 bit / s / Hz and 0.1 bit / s / Hz. and These are the noise power at the covert user Bob and the secure user Carl, respectively, with a value of -40dBm.

5. The information transmission method with friendly interference assistance in an omnidirectional reconfigurable smart surface network according to claim 1, characterized in that: In (5) determining the probability of a security breach, the aforementioned This is the noise power at Eve, the eavesdropper, with a value of -40dBm.

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