Simultaneous Wireless Information Power Transfer for MISO Secrecy Channel

TL;DR

This paper explores secure wireless information and power transfer in MISO channels, proposing optimization algorithms for beamforming with and without artificial noise, considering channel uncertainties and ensuring rank-one solutions.

Contribution

It introduces novel optimization frameworks for SWIPT in MISO secrecy channels, including robust schemes and analysis of rank relaxation tightness, advancing secure energy transfer methods.

Findings

Proposed algorithms effectively optimize secrecy rate and harvested energy.

Robust schemes handle channel uncertainties with two-level optimization.

Simulation results validate the performance and optimality of the algorithms.

Abstract

This paper investigates simultaneous wireless information and power transfer (SWIPT) for multiuser multiple-input-single-output (MISO) secrecy channel. First, transmit beamfoming without artificial noise (AN) design is considered, where two secrecy rate optimization frameworks (i.e., secrecy rate maximization and harvested energy maximization) are investigated. These two optimization problems are not convex, and cannot be solved directly. For secrecy rate maximization problem, we employ bisection method to optimize the associated power minimization problem, and first-order Taylor series expansion is consider to approximate the energy harvesting (EH) constraint and the harvested energy maximization problem. Moreover, we extend our proposed algorithm to the associated robust schemes by incorporating with channel uncertainties, where two-level method is proposed for the harvested energy maximization problem. Then, transmit beamforming with AN design is studied for the same secrecy rate maximization problem, which are reformulated into semidefinite programming (SDP) based on one-dimensional search and successive convex approximation (SCA), respectively. Moreover, tightness analysis of rank relaxation is provided to show the optimal transmit covariance matrix exactly returns rank-one. Simulation results is provided to validate the performance of the proposed algorithm.