Secrecy Wireless Information and Power Transfer in Fading Wiretap Channel

TL;DR

This paper proposes an artificial noise aided scheme for secure wireless information and power transfer in fading channels, optimizing power allocation to enhance secrecy and energy harvesting while addressing non-convex challenges.

Contribution

It introduces a novel AN-assisted transmission scheme with optimized power splitting and allocation for secure SWIPT in fading channels, including optimal and suboptimal solutions.

Findings

Proposed schemes outperform benchmarks in secrecy and energy transfer trade-offs.

Optimized power allocation reduces secrecy outage probability.

Schemes adapt to fading channel conditions for improved performance.

Abstract

Simultaneous wireless information and power transfer (SWIPT) has recently drawn significant interests for its dual use of radio signals to provide wireless data and energy access at the same time. However, a challenging secrecy communication issue arises as the messages sent to the information receivers (IRs) may be eavesdropped by the energy receivers (ERs), which are presumed to harvest energy only from the received signals. To tackle this problem, we propose in this paper an artificial noise (AN) aided transmission scheme to facilitate the secrecy information transmission to IRs and yet meet the energy harvesting requirement for ERs, under the assumption that the AN can be cancelled at IRs but not at ERs. Specifically, the proposed scheme splits the transmit power into two parts, to send the confidential message to the IR and an AN to interfere with the ER, respectively. Under a simplified three-node wiretap channel setup, the transmit power allocations and power splitting ratios over fading channels are jointly optimized to minimize the outage probability for delay-limited secrecy information transmission, or to maximize the average rate for no-delay-limited secrecy information transmission, subject to a combination of average and peak power constraints at the transmitter as well as an average energy harvesting constraint at the ER. Both the secrecy outage probability minimization and average rate maximization problems are shown to be non-convex, for each of which we propose the optimal solution based on the dual decomposition as well as suboptimal solution based on the alternating optimization. Furthermore, two benchmark schemes are introduced for comparison. Finally, the performances of proposed schemes are evaluated by simulations in terms of various trade-offs for wireless (secrecy) information versus energy transmissions.