Relay Selection for Enhancing Wireless Secrecy Against Eavesdropping

Jovana Božović, Enis Kočan

Physical Layer Security (PLS) provides a promising complementary approach to cryptographic methods for protecting wireless communications from eavesdropping. This paper investigates secrecy enhancement through cooperative relaying and jamming in a wireless network with two legitimate users, one eavesdropper, and five potential relay nodes operating in amplify-and-forward mode. Three relay–jammer selection strategies are considered: random relay and jammer selection, best-SNR (signal-to-noise ratio) relay with random jammer selection, and best-SNR relay with a jammer chosen based on the strongest channel toward the eavesdropper. The secrecy performance of these strategies are evaluated in terms of secrecy rate and secrecy outage probability. The results demonstrate that intelligent relay and jammer selection can significantly improve PLS compared to random selection, highlighting the benefits of cooperation in secure wireless systems.

Enyu Li, Zanyang Liang, Ye Wang +1 more

Van Phu Tuan, Hyung Yun Kong

Tin Tran Phu

Security is one of the most important issues in wireless communication.Because using wireless channels entails broadcasting data transmissions, malicious nodes can eavesdrop on wireless transmission, which leads to insecure data transmission.Traditional security methods are based on cryptography.Recently, physical-layer security (PLS) has gained much attention as an efficient method of obtaining secure information without using cryptography.PLS protocols employ the physical characteristics of wireless channels such as channel state information (CSI) and the distances between connection links in order to enhance secrecy performances in wireless systems.To enhance secrecy performances, the dual-hop/multi-hop relay protocols can be used efficiently.However, according to my best knowledge, there are few published works considering the impact of hardware impairments on secrecy performances for the wireless relaying networks.Hence, this dissertation examines the diversity-based relay protocols for wireless communication networks in order to improve secrecy performances in presence of hardware imperfections.First, new dual-hop and multi-hop cooperative relaying schemes with various relay selection methods are proposed in order to obtain improved secrecy performance compared with the existing schemes.Second, new joint relay and jammer selection protocols are also considered in order to improve the channel capacity for data links while reducing the channel capacity of eavesdropping links.Finally, this dissertation proposes harvest-to-transmit and harvest-to-jam protocols, where the relay and jammer nodes harvest energy from the radio frequency signal for use in the data transmission and the jamming process, respectively.To evaluate the performance of the proposed protocols over fading channels, this dissertation focuses on deriving the closed-form expressions for secrecy performances.Then, the derived expressions are verified by Monte Carlo simulations, which also present the advantages of the proposed protocols.

Weijia Lei, Lijie Zuo, Jiang Xue +1 more

Zhixiang Deng, Qian Sang, Yuan Gao +1 more

In this paper, we exploit the potential benefits of machine learning in enhancing physical layer security in cooperative wireless networks. We focus on the case where multiple relays adopt amplify-and-forward (AF) relaying to forward information from the source to the destination. It is assumed that the global channel state information (CSI) of the legitimate links and wiretap links is available to the source. The optimal relay is selected to improve physical layer security against eavesdropping. By modeling the problem of the relay selection as a multi-class classification problem, a neural network (NN) based scheme is proposed to select the optimal relay which guarantees the perfect secrecy performance of the relay cooperative communication system. Compared with the conventional relay selection scheme, the simulation results show that our proposed scheme not only achieves almost the same secrecy performance, but also has advantage of relatively small feedback overhead. The work presented here provides insights into the new design of relay selection based on machine learning.