Secure the cooperative transmission is studied for an automatic repeat request (ARQ)-based wireless network against a jamming-aided eavesdropper. The eavesdropper utilizes the jamming attack to assist its eavesdropping by forcing the legitimate transmitter to retransmit its confidential messages under poor wiretap channel quality. Then, utilizing these retransmission opportunities, the eavesdropper will eavesdrop the confidential message under good wiretap channel quality. To address the threat from the jamming-aided eavesdropper in the ARQ-based wireless network, we propose an adaptive cooperative relaying and jamming secure transmission scheme to protect the confidential messages. In the proposed scheme, the legitimate receiver adopts the energy detection method to detect the jamming-aided eavesdropper's action and a cooperative node will aid the secure transmission through cooperative relaying under jamming attack or cooperative jamming under eavesdropping attack. By taking into account of the detection errors, we investigate the transmission outage probability and the secrecy outage probability, and derive their closed-form expressions for both one retransmission and multiple retransmissions scenarios. Numerical results are presented to verify the derived analytical results and demonstrate the performance superiority of the proposed scheme in terms of the secrecy outage probability.
Secure the cooperative transmission is studied for an automatic repeat request (ARQ)-based wireless network against a jamming-aided eavesdropper. The eavesdropper utilizes the jamming attack to assist its eavesdropping by forcing the legitimate transmitter to retransmit its confidential messages under poor wiretap channel quality. Then, utilizing these retransmission opportunities, the eavesdropper will eavesdrop the confidential message under good wiretap channel quality. To address the threat from the jamming-aided eavesdropper in the ARQ-based wireless network, we propose an adaptive cooperative relaying and jamming secure transmission scheme to protect the confidential messages. In the proposed scheme, the legitimate receiver adopts the energy detection method to detect the jamming-aided eavesdropper's action and a cooperative node will aid the secure transmission through cooperative relaying under jamming attack or cooperative jamming under eavesdropping attack. By taking into account of the detection errors, we investigate the transmission outage probability and the secrecy outage probability, and derive their closed-form expressions for both one retransmission and multiple retransmissions scenarios. Numerical results are presented to verify the derived analytical results and demonstrate the performance superiority of the proposed scheme in terms of the secrecy outage probability.
This paper investigates cooperative security in wireless networks, where a source (Alice) intends to transmit a confidential message to a legitimate destination (Bob), with the help of a cooperative jammer (Charlie), coexisting with multiple passive eavesdroppers (Eves). In particular, by assuming knowledge of Bob's perfect channel state information (CSI) but only Eves’ statistical CSIs, secrecy beamforming with artificial noise (AN) is utilized for secure transmission, and cooperative jamming (CJ) is explored to further enhance secrecy. We first derive an accurate closed-form expression for the secrecy outage probability (SOP), and establish the condition under which positive secrecy rate is achievable. Then, we provide a secure transmit design for maximizing the SOP constrained secrecy rate. Moreover, based on a strict mathematical analysis, we characterize the impact of the main channel quality and the number of Eves on transmit design and secrecy performance. Specifically, optimal power allocation ratio between the information-bearing signal and the AN signal increases as the main channel quality improves, and decreases with the number of Eves. Numerical results confirm that our design achieves performance improvement in terms of both secrecy rate and secure energy efficiency, as compared to the approach without CJ.
Physical layer security is an emerging technique to improve the wireless communication security and the corresponding techniques under practical scenarios especially with imperfect channel state information (CSI) need to be taken into consideration. In this paper, we investigate the robust secure transmission for cooperative decode-and-forward (DF) automatic-repeat-request (ARQ) in multiple-input-single-output (MISO) relaying wiretap channels with channel estimation errors. Firstly, the robust transmit covariance matrices and the optimal beamforming weights are obtained using the semi-definite relaxation (SDR) approach to maximize the secrecy rate under power constraint and channel uncertainties. Besides, we further propose a robust design scheme from the secrecy outage-based characterizations for minimizing the secrecy outage probability of legitimate destination. Moreover, a non-robust scheme, in which the designed beamformer refers to the generalized eigenvectors of the channels' matrix pencil, is also considered as a benchmark. Simulation results verify the robustness of the proposed schemes against the estimation errors and shows that the robust design schemes can significantly improve the security performance of the network.
We investigate the physical layer security in cooperative wireless networks where a source (Alice) transmits a confidential message to a destination (Bob) with the help of a cooperative node (Charlie), in the presence of an eavesdropper (Eve). Cooperative transmission is explored to secure communication between Alice and Bob, while ensuring the desired quality of service (QoS) at Charlie’s receiver. We provide a transmit design for outage constrained secrecy rate maximization, taking both security and QoS constraints into account. Unlike the conventional cooperative security that adopts a fixed transmission scheme, we propose a mechanism for transmit strategy adaptation with security protection. Specifically, the proposed cooperative transmission is replaced by a cooperative jamming scheme if either security or QoS constraint is not satisfied. Numerical results confirm that our design enables dynamic transmission, and thus is flexible and environment-adaptive.
Optimal relay selection is investigated for secure cooperative communications against an adaptive eavesdropper that can perform eavesdropping if the eavesdropping link has good channel quality or perform jamming otherwise. A number of decode-and-forward relays are available for legitimate communications, among which one relay can be selected to help. For legitimate communications, three cases for availability of the eavesdropping channel information are considered: full channel knowledge, partial channel knowledge, and statistical channel knowledge. An optimal relay selection scheme is proposed for each case. For the first and third cases, exact secrecy outage probability expressions in closed form are derived, and for the second case, an approximate secrecy outage probability is derived, which is tight in the high main-to-eavesdropper ratio regime. Moreover, secrecy diversity order for the proposed relay selection scheme in each case is also derived, which is shown to be a full secrecy diversity. Finally, numerical results are given to verify the theoretical analysis derived in this paper.
An adaptive cooperative scheme is proposed to improve the security of a wireless-powered relay network. A source node sends data to a destination node in the presence of an amplify-and-forward untrusted relay node and an alien eavesdropper where both are assumed to attempt to decode the source’s information signal. The source uses a fraction of its transmit power to send a jamming signal to keep its information confidential. To save energy, the energy-harvesting relay node transmits with the minimum power level that ensures secure transmissions. We derive a closed-form upper bound on the system’s secrecy outage probability. The proposed cooperative scheme is more efficient than the conventional scheme, where once the relay has accumulated sufficient energy, it assists the source’s information transmission.
In this paper, we investigate cooperative security in wireless networks, where a source (Alice) intends to transmit a confidential message to a legitimate destination (Bob), with the help of a cooperative node (Charlie), in the presence of multiple independent eavesdroppers (Eves). In particular, cooperative jamming (CJ) is explored to enhance secure communication between Alice and Bob. We provide a transmit design to maximize the secrecy rate, subject to a secrecy outage probability (SOP) constraint. Specifically, we establish a condition under which positive secrecy rate can be guaranteed. In addition to secrecy rate performance, we also pay attention to the secure energy efficiency, defined as the ratio of secrecy rate to total power consumption. Numerical results validate the effectiveness and energy efficiency of our proposed CJ scheme.