In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward relay network over independent but not necessarily identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. Based on whether the channel state information (CSI) of the wiretap links is available or not, we analyze the secrecy outage performance with optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes, and multiple relays combining scheme (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for the secrecy outage probability with three different relay selection schemes are derived and verified by Monte-Carlo simulations. The numerical results illustrate that ORS scheme always outperforms SRS and MRC schemes, and SRS scheme is better than MRC scheme in the lower fading parameters scenario. Furthermore, through asymptotic analysis, we find that these three different schemes achieve the same secrecy diversity order, which is determined by the number of the relays, and the fading parameters of the links among the relays and the destination.
|Number of pages
|IEEE Transactions on Cognitive Communications and Networking
|Published - Oct 2 2017
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported in part by the National Natural Science Foundation of China (NSFC) under Grant 61471076, Chinese Scholarship Council under Grant 201607845004, the Program for Changjiang Scholars and Innovative Research Team in University under Grant IRT 16R72, the special fund for Key Lab of Chongqing Municipal Education Commission, the Project of Fundamental and Frontier Research Plan of Chongqing under Grant cstc2015jcyjBX0085 and cstc2017jcyjAX0204, and the Scientific and Technological Research Program of Chongqing Municipal Education Commission under Grant KJ1600413 and KJ1704088. Parts of this publication were made possible by NPRP (National Priorities Research Program) grant # NPRP8-648-2-273.