Joint Power Splitting and Secure Beamforming Design in the Multiple Non-Regenerative Wireless-Powered Relay Networks

Abstract

The physical-layer security issue in the multiple non-regenerative wireless-powered relay (WPR) networks is investigated in this letter, where the idle relay is treated as a potential eavesdropper. To guarantee secure communication, the destination-based artificial noise is sent to degrade the receptions of eavesdroppers, and it also becomes a new source of energy powering relays to forward the information with power splitting (PS) technique. We propose an efficient algorithm ground on block-wise penalty function method to jointly optimize PS ratio and beamforming to maximize the secrecy rate. Despite the nonconvexity of the considered problem, the proposed algorithm is numerically efficient and is proved to converge to the local optimal solution. Simulation results demonstrate that the proposed algorithm outperforms the benchmark method.Index Terms-Energy harvesting, non-regenerative relaying, power splitting (PS), beamforming, multiple wireless-powered relays, physical-layer security, artificial noise.

Wireless powered large-scale multi-antenna AF relaying for cooperative jamming-aided secrecy

“…Plugging into (24) (14) and (17), the approximate expression for r (inst) sec when the number of relay antennas N tends to be very large is thus obtained. Considering the no-delay-limited secrecy information transmission to the destination, ESR is a relevant metric that is given by [22] …”

“…WEH-enabled amplify-and-forward (AF) relays have been early investigated in [13]. Later their receiver (Rx) structure was further optimized for purely cooperative beamforming (CB), and joint CB and CJ in [14] and [15], respectively. Secret transmission assisted by a wireless powered massive MIMO relay through WPT from the source was considered in [16], where explicit expressions of secrecy outage capacity were derived under the assumption of imperfect legitimate CSI and no eavesdropper's CSI to show that the challenging "long transfer distance" issue has been well addressed.…”

Wireless Powered Cooperative Jamming for Secrecy Multi-AF Relaying Networks

“…We consider the use of the dynamic power splitting (DPS) receiver architecture, initially proposed for SWIPT in [22], which divides the received power with an adjustable ratio for energy harvesting (EH) and information receiving (IR). WEHenabled relays using DPS receivers have also been considered in [23][24][25] and [26,27,29], without (w/o) and with secrecy consideration, respectively. Note that there is also interest in addressing the threat that WEH receivers may attempt to intercept the confidential messages in SWIPT-enabled networks [28][29][30][31].…”

“…1 In this paper, we assume that there is no direct link between the source and destination nodes, and perfect global channel state information (CSI) is available for the case of centralized optimization.It is worth pointing out that although our setting may look similar to [20], their optimal CB-CJ design is not applicable to ours due to the multiplicative nature in beamforming weights incurred by the power splitting (PS) ratios that intrinsically poses more intractability to our optimization problem. Further, our work also differs from [27] where an efficient algorithm was proposed to maximize the secrecy rate for the optimization of the PS ratios and AF relay beamforming. The difference is twofold.…”

“…The difference is twofold. First, AN was not considered in the second transmission phase in [27] and in addition, their algorithm only converged to a local optimum, as opposed to our work that gives the global optimal solutions for CB.The rest of the paper is organized as follows. Section II describes two types of WEH-enabled Rx architecture for the AF relays and defines the secrecy rate region of the relay wiretap channel.…”