This paper investigates the secrecy performance of a full-duplex relaying (FDR) system with a full-duplex (FD) receiver. A novel cooperative jamming protocol is proposed to improve physical layer security, where the FD receiver sends interference to the eavesdropper to degrade its received signal-to-noise ratio when receiving signals from the relay and the source. Taking the residual self-interference (RSI) at both the relay and the FD receiver into consideration, the expressions of secrecy outage probability of the system are derived, where two independent behaviors of the relay toward the jamming signal are considered, 1) the jamming signal from the FD receiver is recognized as an interference at the relay; and 2) the jamming signal is priori known at the relay. Simulation results verified the correctness of the derived expressions and the effectiveness of the proposed protocol. It is demonstrated that the secrecy performance of the system can be significantly enhanced and the gain in terms of the decreased secrecy outage probability becomes more evident in case that the RSI is somewhat low when the proposed protocol is used.
This paper investigates the secrecy performance of a full-duplex relaying (FDR) system with a full-duplex (FD) receiver. A novel cooperative jamming protocol is proposed to improve physical layer security, where the FD receiver sends interference to the eavesdropper to degrade its received signal-to-noise ratio when receiving signals from the relay and the source. Taking the residual self-interference (RSI) at both the relay and the FD receiver into consideration, the expressions of secrecy outage probability of the system are derived, where two independent behaviors of the relay toward the jamming signal are considered, 1) the jamming signal from the FD receiver is recognized as an interference at the relay; and 2) the jamming signal is priori known at the relay. Simulation results verified the correctness of the derived expressions and the effectiveness of the proposed protocol. It is demonstrated that the secrecy performance of the system can be significantly enhanced and the gain in terms of the decreased secrecy outage probability becomes more evident in case that the RSI is somewhat low when the proposed protocol is used.
This paper investigates how to improve the physical-layer security for two-way relay systems with the help of a full-duplex relay (FDR). Based on the particularity of two-way relay, a novel FDR-based half-jamming protocol is proposed. In the first time slot, the relay splits a portion of its power to transmit jamming noise against eavesdropping attacks, while simultaneously receiving the sources' signal by operating in FD mode. In the second time slot, the relay operates in half-duplex mode for broadcasting the overlapped signals from the two sources. Closed-form expression of sum secrecy rate is given. Simulation results has shown that considerable performance gain is achieved compared with no jamming protocol.
This letter studies secure communications in a full-duplex relay (FDR) network when an eavesdropper overhears communications between legitimate parties. In a FDR network, both the amplify-and-forward relay and the destination operate in full-duplex for the purpose of achieving a higher secrecy rate and/or improving security. In particular, the destination is capable of receiving the relayed signal and simultaneously emitting a cooperative jamming signal. This work is motivated by an intriguing question: how much residual self-interference (SI) in a FDR network is allowed to achieve a superiority of secrecy performance over conventional half-duplex relay (HDR) networks? To answer the question, the secrecy outage probability (SOP) of the FDR network is derived as a function of residual SI. The analytic results enable us to compare the SOPs of existing HDR networks and the FDR network at various levels of residual SI. In addition, this work allows one to opportunistically select either FD or HD, which leads to a significant performance improvement.
This paper studies the secrecy outage probability of full-duplex (FD) relay networks in the presence of external eavesdropper and residual self-interference, where the FD relay can forward message or transmit jamming signal. Different with the existing researches which consider the full-duplex relay employs decode-and-forward (DF) protocol, we study the situation that the FD relay uses amplify-and-forward (AF) protocol, and propose a destination aided jamming scheme to further improve the secrecy performance when the FD relay transmits jamming. Furthermore, we compare the secrecy outage probability of four different schemes (i.e., AF forwarding scheme, AF destination- aided jamming scheme, DF forwarding scheme and DF jamming scheme), and give the answer that which mode the FD relay should employ with different system parameters.
In this paper, we examine the use of a friendly full-duplex (FD) relay to increase the secrecy rate over a fading channel between the legitimate source and the destination in the presence of residual self-interference (SI) and eavesdropper. In particular, we consider two different protocols based on the FD capability of relay: 1) FD transmission (FDT), in which the FD-Relay receives and sends data concurrently; 2) FD-Relay with jamming (FDJ), where first, the FD-Relay simultaneously receives data and sends jamming to the eavesdropper; then, it forwards the data, while the source jams the eavesdropper. We first develop the secrecy rate expressions for half-duplex transmission (HDT), half-duplex with jamming (HDJ), FDT, and FDJ relaying protocols, and then use them to derive their performance properties in terms of the channel gains between nodes, eavesdropper types, and more importantly, the SI level in FD-Relay. We further investigate the non-convex power allocation problems for the developed FDT and FDJ to maximize the secrecy rate under the power constraints. In particular, we develop an efficient iterative algorithm based on the difference-of-two-concave-functions programming. Analytical and simulation results show the strong influence of SI level on the achieved secrecy rate of the FDT and the FDJ. For sufficiently low SI, FDT achieves a much higher secrecy rate than FDJ, HDJ, and HDT. However, for higher SI, FDJ becomes more effective in enhancing the achieved secrecy rate. The results also indicate that adaptive power allocation can significantly improve the performance and confirm that the proposed FDT and FDJ outperform the HDT and the HDJ.
This paper proposes a jointly cooperative relay and jamming protocol based on full-duplex (FD) capable relay to increase the source-destination secrecy rate in the presence of different types of eavesdroppers. In this so called FD-Relay with jamming (FDJ) protocol, the FD-Relay, first, simultaneously receives data and sends jamming to the eavesdropper, and, then, forwards the data, while the source jams the eavesdropper. Achievable secrecy rates of the proposed FDJ in the presence of different eavesdropper types and self-interference (SI) are derived and compared with those of the traditional half-duplex (HD) relay. The adaptive power allocation for secrecy rate maximization in a multi-carrier scenario for both proposed FDJ and HD-Relay is formulated as a non-convex optimization problem and corresponding iterative solution algorithm is developed using the difference-of-two-concave-functions (DC) programming technique. The simulation results confirm that FDJ offers significant improvements in the secrecy rate over the HD-Relay.
This paper investigates the secrecy performance of full-duplex relay (FDR) networks. The resulting analysis shows that FDR networks have better secrecy performance than half duplex relay networks, if the self-interference can be well suppressed. We also propose a full duplex jamming relay network, in which the relay node transmits jamming signals while receiving the data from the source. While the full duplex jamming scheme has the same data rate as the half duplex scheme, the secrecy performance can be significantly improved, making it an attractive scheme when the network secrecy is a primary concern. A mathematic model is developed to analyze secrecy outage probabilities for the half duplex, the full duplex and full duplex jamming schemes, and the simulation results are also presented to verify the analysis.