Robust beamforming and cooperative jamming for secure transmission in DF relay systems

Abstract

In this paper, we study robust joint beamforming and cooperative jamming (CJ) in a secure decode-and-forward (DF) relay system in the presence of multiple eavesdroppers, in which a multi-antenna DF relay employs transmit beamforming to help the source deliver information to the destination and simultaneously generates Gaussian artificial noise to confuse these eavesdroppers. We assume that all the channel state information (CSI) is imperfectly known at the relay subject to norm-bounded CSI errors. Our objective is to maximize the achievable secrecy rate at the destination by jointly optimizing the transmit beamforming vector of information signals and the covariance matrix of jamming signals at the relay subject to its total transmit power constraint. Although this problem is non-convex and in general difficult to be solved, we obtain its optimal solution via the technique of semi-definite relaxation (SDR) together with a one-dimensional (1-D) search. Specifically, we prove that the SDR is tight for the problem of our interest. Finally, numerical results are provided to validate our proposed scheme.

Individual secrecy of fading homogeneous multiple access wiretap channel with successive interference cancellation

“…By observing (16), it is easy to find that U(k, θ) is a decreasing function of θ and/or k. Particularly, U(k, θ) → 0 as k or θ →∞. Since the term I 2 in (13) is a non-negative linear combination of the decreasing function U(k, θ), it decreases with n or R s increasing by fixing the other arguments.…”

“…A great deal of research work addressed how to improve secrecy performance, some from the perspective of precoding and beamforming [7][8][9][10], some via the utilization of artificial noise or jamming [11][12][13][14], and some jointly applying these approaches [15][16][17][18]. Overall, the purpose of exploiting these techniques is to enlarge the capacity difference between main and eavesdropper channels.…”

Joint distributed beamforming and jamming schemes in decode-and-forward relay networks for physical layer secrecy

“…Observe (25) and (11), we can also apply Algorithm 1 to solve the problem (25). Then, we can obtain the optimal jamming vector w J for a given P j .…”

“…., L so that the problem (12) will be operated L times. According to [25] and [36], the computational complexity of an inner level optimization (12) is O (N + 1) 0.5 (2(N + 1) 3 + 4(N + 1) 2 + 8) log(1/ ) in which is the accuracy of solving the SDP. Please note that in Algorithm 1, running L times of problem (12) is activated after τ min and τ max are determined.…”

“…If there exists the direct link from the source to the destination, cooperative jamming (CJ) and transmission switching between CB and CJ were also proposed to improve the system secrecy [23,24]. Moreover, joint CB and CJ schemes in co-located multi-antenna scenarios were also investigated in [25] and [26]. In [27], we have investigated the optimal joint CB and CJ scheme for the DF relay networks with direct links from the source to destination and eavesdropper.…”