Robust secrecy beamforming for wireless information and power transfer in multiuser MISO communication system

Wei Wu,Baoyun Wang

doi:10.1186/s13638-015-0378-2

Abstract

In this paper, we study the max-min fairness for robust secrecy beamforming design in a multiuser MISO communication system with simultaneous wireless information and power transfer (SWIPT). In particular, the imperfect channel state information (CSI) and power splitting information receiver (IR) are taken into account. We model the design as an optimization problem which maximizes the minimum harvested energy among the multi-antenna energy receivers (ERs). Besides, both the secure communication requirement and the lowest electrical energy storage threshold at IR must be guaranteed in our formulated optimization problem. The considered max-min problem is non-convex and hard to tackle. By introducing the technique of semidefinite relaxation (SDR), we prove the tightness of this relaxation and obtain the global optimal solution of our original optimization problem. Moreover, a suboptimal beamforming design scheme is proposed with low computational complexity. Simulation results show that our proposed robust schemes are more efficient than other schemes in terms of energy harvesting and transmit power saving.

Highlights

The rapid growth of wireless communication requirement brings abundant energy consumption, which leads to the conventional battery-powered wireless communication devices encountering a bottleneck in providing sufficient power
We studied the problem of fair energy harvesting among all energy receivers (ERs) by considering imperfect channel state information (CSI) and power splitting information receiver (IR) in the multiuser MISO communication system
5 Conclusions An optimal robust secrecy beamforming design for MISO communication system with simultaneous wireless information and power transfer (SWIPT) was investigated in this paper

Summary

Introduction

The rapid growth of wireless communication requirement brings abundant energy consumption, which leads to the conventional battery-powered wireless communication devices encountering a bottleneck in providing sufficient power. Two kinds of suboptimal solutions are proposed to achieve the lower bound of robust secrecy rate since the optimal solution is hard to acquire in [7] Both the system with perfect and imperfect CSIs are studied in [8], where the optimal power allocation scheme. We concentrate on the optimal secrecy beamforming design for SWIPT in a multiuser MISO communication system with multiple multi-antenna ERs. The CSIs between transmitter and ERs are assumed to be imperfect. We studied the problem of fair energy harvesting among all ERs by considering imperfect CSI and power splitting IR in the multiuser MISO communication system. IN denotes the N × N identity matrix; CN×M and HN+ denote the N ×M complex matrices and N ×N Hermitian matrices, respectively. · 2 means the Euclidean norm of a vector while · F means the Frobenius norm of a matrix; null (·) denotes the null space of a vector or matrix. x ∼ CN (μ, ) means the vector x is a complex Gaussian variable with mean μ and covariance

System model

Suboptimal downlink beamforming design

Simulation results

Average total harvested power

Conclusions