The utilization of other devices as relays in cooperative device-to-device (D2D) communication systems does not fully guarantee the security of confidential information from being intentionally or unintentionally accessed by eavesdroppers. Therefore, the implementation of a method to enhance the security performance of information is highly necessary. This paper proposes the application of relay selection mechanisms in a communication system with three relay protocols: Amplify-and-Forward (AF), Decode-and-Forward (DF), and Quantize-and-Forward (QF). The research method employs a mathematical modeling approach and simulations. The simulation results demonstrate an improvement in the level of information security in cooperative D2D communication systems using the proposed method in multiple relay protocols. The relay selection method has been evaluated and compared based on the Secrecy Outage Probability (SOP), which is one of the parameters for information security in the communication system. The SOP achieved is smaller with the implementation of the Max-Min relay selection technique in multi-relay cooperative communication networks. Considering the presence or absence of eavesdroppers, the SOP of the DF relay is smaller compared to other protocols. The impact of distance on secrecy capacity also indicates that the DF protocol utilizing multiple relays achieves higher results compared to other protocols, and the increased usage of relays also affects the simulation outcomes.
The utilization of other devices as relays in cooperative device-to-device (D2D) communication systems does not fully guarantee the security of confidential information from being intentionally or unintentionally accessed by eavesdroppers. Therefore, the implementation of a method to enhance the security performance of information is highly necessary. This paper proposes the application of relay selection mechanisms in a communication system with three relay protocols: Amplify-and-Forward (AF), Decode-and-Forward (DF), and Quantize-and-Forward (QF). The research method employs a mathematical modeling approach and simulations. The simulation results demonstrate an improvement in the level of information security in cooperative D2D communication systems using the proposed method in multiple relay protocols. The relay selection method has been evaluated and compared based on the Secrecy Outage Probability (SOP), which is one of the parameters for information security in the communication system. The SOP achieved is smaller with the implementation of the Max-Min relay selection technique in multi-relay cooperative communication networks. Considering the presence or absence of eavesdroppers, the SOP of the DF relay is smaller compared to other protocols. The impact of distance on secrecy capacity also indicates that the DF protocol utilizing multiple relays achieves higher results compared to other protocols, and the increased usage of relays also affects the simulation outcomes.
With increasing the demand for transmitting secure information in wireless networks, device-to-device (D2D) communication has great potential to improve system performance. As a well-known security risk is eavesdropping in D2D communication, ensuring information security is quite challenging. In this paper, we first obtain the closed-forms of the secrecy outage probability (SOP) and the secrecy ergodic capacity (SEC) for direct and decode- and-forward (DF) relay modes. Numerical results are presented to verify the theoretical results, and these results show the cases that the DF relay mode improves security performance compared to the direct mode at long distances between the transmitter and receiver nodes. Further, we look into the optimization problems of secure resource allocation in D2D communication to maximize the SEC and to minimize the SOP by considering the strictly positive secrecy capacity constraint as a mixed-integer non-linear programming (MINLP) problem. In the continue, we convert the MINLP to convex optimization. Finally, we solve this program with a dual method and obtain an optimal solution in the direct and DF relay modes.
In this paper, we consider a cooperative relay network consisting of a source, a destination, and multiple decode-and-forward (DF) relays in the presence of multiple eavesdroppers, which intend to tap confidential messages transmitted by both the source and the relays. We propose a so-called secrecy maximization oriented relay selection (SMORS) scheme to improve the physical-layer security of wireless communications. In the SMORS scheme, a relay with the maximal secrecy rate is selected among all the DF relays to forward the source signal. We analyze the intercept probability of the proposed SMORS scheme as well as the traditional max-min relay selection scheme. Numerical results show that the proposed SMORS scheme outperforms the conventional max-min relay selection scheme in terms of the intercept probability. Additionally, it is shown that with an increasing number of eavesdroppers, the intercept performance of wireless communications degrades, which can be well addressed using the proposed SMORS scheme through increasing the number of relays. By contrast, increasing the number of relays has little impact on the intercept probability for the conventional max-min relay selection scheme, especially when the number of relays is sufficiently high (e.g., exceeding 20 relays).
In this paper, a confidential communication scenario is considered through selection decode-and-forward cooperative relay networks over Rayleigh fading channel in which a source communicates with a destination via multiple relays. A best relay is selected using selection combining technique which communicates with the destination. An eavesdropper observes their communication and tries to decode confidential information. In this situation, an interest is given to ensure secure communication between the best relay and the destination so that eavesdropper is unable to decode any information from the main channel (i.e. channel between relay and destination). The performance of the proposed model is analyzed based on the closed-form analytical expressions of the ergodic secrecy capacity and the secure outage probability taking into account the distances of relays from the source, destination and the eavesdropper. Analytical results show that the additional diversity provided by the best relay situated in a strategic location significantly improves the secure outage performance of the selection decode-and-forward relay networks.
In the last decade, multi-hop cooperation has evolved bringing several advantages including coverage improvement, more reliability of wireless links, and power consumption reduction. Still, its application has raised several challenges, such as the need for secure transmission at each hop, algorithms to perform relay selection and the accurate models to facilitate performance analysis. This paper addresses the problem of physical layer (PHY) security in a multi-hop wireless cooperative network, where communication at each hop is assisted by multiple relays forming a cluster, each cluster being surrounded by multiple eavesdroppers which together may tap transmissions from both the source and the relays. The main focus of the study is on analyzing the benefits of various relay selection schemes for protecting the source-destination transmission against the eavesdroppers, which can collude and combine information via diversity combining techniques. To be specific, four relay selection schemes, which differ in the way they employ available measures link quality, are considered to deliver the source information to the destination via a decode-and-forward (DF) strategy. To evaluate the security performance of the multi-hop cooperative link in the presence of colluding eavesdroppers, we derive novel closed-form analytical expressions for the secrecy outage probability (SOP) with consideration of special cases of practical interest.
In the last decade, multi-hop cooperation has evolved bringing several advantages including coverage improvement, more reliability of wireless links, and power consumption reduction. Still, its application has raised several challenges, such as the need for secure transmission at each hop, algorithms to perform relay selection and the accurate models to facilitate performance analysis. This paper addresses the problem of physical layer (PHY) security in a multi-hop wireless cooperative network, where communication at each hop is assisted by multiple relays forming a cluster, each cluster being surrounded by multiple eavesdroppers which together may tap transmissions from both the source and the relays. The main focus of the study is on analyzing the benefits of various relay selection schemes for protecting the source-destination transmission against the eavesdroppers, which can collude and combine information via diversity combining techniques. To be specific, four relay selection schemes, which differ in the way they employ available measures link quality, are considered to deliver the source information to the destination via a decode-and-forward (DF) strategy. To evaluate the security performance of the multi-hop cooperative link in the presence of colluding eavesdroppers, we derive novel closed-form analytical expressions for the secrecy outage probability (SOP) with consideration of special cases of practical interest.
Cooperative communication in wireless relay systems can improve the physical layer security, and the relay selection has great impacts on the security performances. In this paper the relay selection in Amplify-and-Forward (AF) cooperative networks is investigated. The system model constitutes of a source, an eavesdropper, a destination, and a number of intermediate nodes with secrecy constraints. The proposed optimal selection (OS) algorithm is based on the instantaneous channel state information (CSI) of two hops, jointly protects the target destination against eavesdropping and interference. To simplify the complexity of OS, the suboptimal selection (SS) algorithm is also presented, which is based on the instantaneous of the first hop and the statistical CSI of the second hop respectively. The secrecy capacity and secrecy outage probability of these two relay selection algorithms are analyzed. Simulation results of OS and SS validate our theoretical analysis and show enhancement in the secrecy rate over the direct transmission.