The two-stage physical layer security transmission scheme based on Simultaneous Wireless Information and Power Transfer and friendly jamming signals aided is proposed to solve the energy-constrained problem of signal processing and secure transmission issues of confidential information upon the multi-antenna relay systems. First, a multi-antenna relay system model based on the amplify-and-forward protocol is established. Then, Considering the scenario of multiple eavesdroppers and non-collusion eavesdropping, Analyzing the transmission process of system energy and information, the optimal transmission antenna selection strategy and the optimal jamming antenna selection strategy are respectively proposed in order to maximize the secrecy performance of the system. Next, the closed-form expressions of the system secrecy outage probability are derived. Finally, the Monte Carlo simulation method is applied to verify the correctness of the theoretical derivation, and the influence of parameters such as the transmit signal-to-noise ratio, power splitting factor and power allocation coefficient on the secrecy performance of the system is analyzed. The simulation results show that the proposed transmission scheme outperforms compared with the existing security transmission scheme.
The two-stage physical layer security transmission scheme based on Simultaneous Wireless Information and Power Transfer and friendly jamming signals aided is proposed to solve the energy-constrained problem of signal processing and secure transmission issues of confidential information upon the multi-antenna relay systems. First, a multi-antenna relay system model based on the amplify-and-forward protocol is established. Then, Considering the scenario of multiple eavesdroppers and non-collusion eavesdropping, Analyzing the transmission process of system energy and information, the optimal transmission antenna selection strategy and the optimal jamming antenna selection strategy are respectively proposed in order to maximize the secrecy performance of the system. Next, the closed-form expressions of the system secrecy outage probability are derived. Finally, the Monte Carlo simulation method is applied to verify the correctness of the theoretical derivation, and the influence of parameters such as the transmit signal-to-noise ratio, power splitting factor and power allocation coefficient on the secrecy performance of the system is analyzed. The simulation results show that the proposed transmission scheme outperforms compared with the existing security transmission scheme.
This paper investigates secure communications of energy harvesting untrusted relay networks, where the destination assists jamming signal to prevent the untrusted relay from eavesdropping and to improve the forwarding ability of the energy constrained relay. Firstly, the source and the destination transmit the signals to the relay with maximal ratio transmission (MRT) technique or transmit antenna selection (TAS) technique. Then, the destination utilizes maximal ratio combining (MRC) technique or receive antenna selection (RAS) technique to receive the forwarded information. Therefore, four transmission and reception schemes are considered. For each scheme, the closed-form expressions of the secrecy outage probability (SOP) and the connection outage probability (COP) are derived. Besides, the effective secrecy throughput (EST) metric is analyzed to achieve a good tradeoff between security and reliability. In addition, the asymptotic performance of EST is also considered at the high signal-to-noise ratio (SNR). Finally, simulation results illustrate that: (1) the EST of the system with MRT and MRC scheme are superior to other schemes, however, in the high SNR regime, the EST of the system with MRT scheme is inferior to TAS; and (2) for the source node, there exists an optimal number of antennas to maximize the EST of the proposed schemes.
This paper studies a scheme of optimal relay selection with cooperative jamming and optimal power allocation factor between forwarding relay and jammer.The traditional optimal relay selection scheme selects an optimal relay node to assist forward source information.Based on legitimate user and eavesdropper instantaneous channel state information, the proposed scheme selects two relay nodes to increase security against eavesdropper.The first relays to forward source information as traditional scheme.The second relays to send artificial noise as a friendly jammer.The relay operates in Decode-and-Forward strategy.The closed form expression of secrecy outage probability is derived.In addition, the optimal power allocation factor is given when the total relay transmit power is constrained.The simulation results verify that the proposed scheme can significantly improve system security performance compared with the traditional scheme.,
In this paper, the physical-layer security of a cooperative wireless system with multi-antenna full-duplex (FD) destination is examined. More specifically, we consider a cooperative transmission scenario in which a source communicates with a destination through a relay in the presence of an eavesdropper. In order to degrade the wiretap channel, the FD destination simultaneously transmits an interference signal towards the eavesdropper, while receiving information from the relay. A joint transmit and receive beamformer design is proposed to maximize the signal-to-interference-plus-noise ratio (SINR) at the destination, while guaranteeing that the SINR at the eavesdropper is below a certain threshold. We reformulate the optimization problem as a semidefinite relaxation problem in terms of a transmit beamforming matrix. To balance the performance and system complexity, we investigate suboptimum beamforming designs based on zero-forcing criterion. We derive exact closed-form expressions for the average secrecy rates of the proposed suboptimum designs. Our results reveal that optimum and suboptimum beamforming schemes along with friendly jamming significantly improve the secrecy performance. Moreover, simulation results demonstrate that the optimum scheme outperforms suboptimum schemes, especially in high transmit power regimes.
In this paper, the secrecy outage performance of a three-node amplify-and-forward relay network with an untrustworthy relay is investigated. To enable a secure transmission, we consider a destination-based jamming technique to prevent the relay from successfully decoding the secret messages between the source and the destination. In addition, the relay is assumed to be an energy-constrained device, thus being first energized by the source in order to be able to retransmit the information to the destination. In doing so, a time switching-based simultaneous wireless information and power transfer scheme is used. A closed-form asymptotic expression for the secrecy outage probability is derived in order to obtain a tight approximation at medium-to-high signal-to-noise ratio. The accuracy of the performed analysis is corroborated by Monte Carlo simulations through different illustrative cases. Numerical results show the impact of key system parameters on the secrecy performance, such as the time allocation factor between the energy harvesting and information transmission phases, the power allocation factor between source and destination for cooperative jamming, and the relay position, so as to provide insights on the design criteria for energy efficient and secure networks.
We study a relay and user selection scheme to improve the secrecy performance of cooperative multi-user multiple amplify-and-forward (AF) relay network. Nevertheless, relay transmission is highly susceptible to eavesdropping since confidential information is broadcasted twice, i.e., by the source and the relay. In particular, we propose a cooperative jamming aided secure transmission through the relay path. Furthermore, with the presence of the direct path, a transmission mode selection scheme is elaborated in such a way to reduce the amount of information leaked to non-selected users in the system, who may overhear the source message as eavesdroppers. Specifically, the selected relay is only activated when it has better secrecy performance than the source. We study the impact of outdated channel state information (CSI) on the system by deriving a closed-form lower bound for the secrecy outage probability (SOP). By investigating the effect of the jamming power level and the correlation coefficients imbalance, a comparison reveals that the proposed scheme outperforms the fixed transmission modes and its signal-to-noise ratio based counterpart. It is shown that the secrecy outage probability can be decreased as the number of destinations grows unless the number of relays is small. Importantly, optimal relay location and jamming power allocation significantly enhance the secrecy performance.
To improve physical (PHY) layer security of a wireless relay system in the presence of an eavesdropper, a two-phase cooperative relaying scheme is investigated in this paper. In phase I, the source transmits confidential message, simultaneously, it cooperates with the friendly jammers and destination to create jamming signal at the eavesdropper without affecting the forwarding relay which is preselected. In phase II, the forwarding relay retransmits the decoded signal, meanwhile, the particular relay cooperates with the friendly jammers to create jamming signal at the eavesdropper without affecting the destination. We focus on the investigation of optimal power allocation for maximizing achievable secrecy rate subject to a total power constraint. Optimal relay selection and suboptimal relay selection schemes are also proposed. It is shown that as the number of relays increases, both secrecy rate and the performance of suboptimal relay selection scheme improve significantly. Numerical results are presented to validate the derived analytical results and compare them to existing work.