AN-Aided Transmit Beamforming Design for Secured Cognitive Radio Networks with SWIPT

Weili Ge,Zhongyong Wang,Zhengdao Yuan,Zhengyu Zhu

doi:10.1155/2018/6956313

Abstract

We investigate multiple-input single-output secured cognitive radio networks relying on simultaneous wireless information and power transfer (SWIPT), where a multiantenna secondary transmitter sends confidential information to multiple single-antenna secondary users (SUs) in the presence of multiple single-antenna primary users (PUs) and multiple energy-harvesting receivers (ERs). In order to improve the security of secondary networks, we use the artificial noise (AN) to mask the transmit beamforming. Optimization design of AN-aided transmit beamforming is studied, where the transmit power of the information signal is minimized subject to the secrecy rate constraint, the harvested energy constraint, and the total transmit power. Based on a successive convex approximation (SCA) method, we propose an iterative algorithm which reformulates the original problem as a convex problem under the perfect channel state information (CSI) case. Also, we give the convergence of the SCA-based iterative algorithm. In addition, we extend the original problem to the imperfect CSI case with deterministic channel uncertainties. Then, we study the robust design problem for the case with norm-bounded channel errors. Also, a robust SCA-based iterative algorithm is proposed by adopting the S-Procedure. Simulation results are presented to validate the performance of the proposed algorithms.

Highlights

The fifth-generation (5G) wireless technology is expected to satisfy an increasing demand for wireless device, such as high data service and radio coverage [1, 2]
Motivated by the above observations, in this paper, we study secrecy transmission over a MISO cognitive radio (CR) system with simultaneous wireless information and power transfer (SWIPT), which consists of one primary transmitter-receiver pair, one multiantenna secondary transmitter (ST), multiple secondary users (SUs), and multiple energy-harvesting receivers (ERs)
We compare the following transmit designs: the perfect channel state information (CSI) case, robust successive convex approximation (SCA)-based scheme, no-artificial noise (AN) scheme which is obtained by setting Z = 0, and the nonrobust scheme which assumes no uncertainty in the CSI

Summary

Introduction

The fifth-generation (5G) wireless technology is expected to satisfy an increasing demand for wireless device, such as high data service and radio coverage [1, 2]. As one of the most efficient ways to alleviate the problem of spectrum scarcity for green communications and networks, cognitive radio (CR) is a promising approach for heightening the spectrum utilization ratio [6, 7]. CR technology can significantly increase in the spectrum efficiency, the energy scarcity still give rise to a major bottleneck problem for the quality of service (QoS) and the long lifetime of wireless users [9]. A promising technique, simultaneous wireless information and power transfer (SWIPT), has been proposed to use the radio frequency- (RF-) enabled signal harvesting power in wireless networks, which can greatly help to solve the bottleneck problem of energy scarcity [10,11,12,13,14,15,16,17,18]. The SWIPT approach for CR schemes was investigated in cooperative relay networks [21], a thresholding-based antenna selection multiple-input

Objectives

Results

Conclusion