On Secure Underlay MIMO Cognitive Radio Networks With Energy Harvesting and Transmit Antenna Selection

In this paper, we consider an underlay multiple-input-multiple-output (MIMO) cognitive radio network (CRN) including a pair of primary nodes, a couple of secondary nodes, and an eavesdropper, where the secondary transmitter is powered by the renewable energy harvested from the primary transmitter in order to improve both energy efficiency and spectral efficiency. Based on whether the channel state information of wiretap links are available or not, the secrecy outage performance of the optimal antenna selection (OAS) scheme and suboptimal antenna selection (SAS) scheme for underlay MIMO CRN with energy harvesting are investigated and compared with traditional space-time transmission scheme. The closed-form expressions for exact and asymptotic secrecy outage probability are derived. Monte-Carlo simulations are conducted to testify the accuracy of the analytical results. The analysis illustrates that the OAS scheme outperforms SAS scheme. Furthermore, the asymptotic result shows that no matter which scheme is considered, the OAS and SAS schemes can achieve the same secrecy diversity order.

I. Introduction

Energy harvesting (EH) technology is integrated into wireless communication as a powerful solution to the problem of limited network lifetime, which collects energy from natural resources (solar, wind, vibration, etc.) and synthesized resources (microwave power transfer) and transforms into electricity to power wireless equipments [1], [2]. In recent years, simultaneous wireless information and power transfer (SWIPT) has gained a great deal of attention from researchers, which transport both energy and information to destinations by utilizing the same emitted electromagnetic wave [3], [4]. Two practical receiver designs for SWIPT, time splitting (TS) and power splitting (PS) schemes, were proposed for practical SWIPT receiver designs to realize receiving the information and energy simultaneously in [5] and [6]. A dynamic gradient-aware hierarchical packet forwarding mechanism is designed in [7] to extend the SWIPT networks life. The outage and capacity performance of a wireless sensor networks with TS/PS schemes over Nakagami- fading channels was investigated in [8].