Outage Analysis in Multi-user and Multi-relay Cognitive AF Relaying Networks Using MRC

摘要

This paper investigates the outage performance in multi-user and multi-relay cognitive amplify-and-forward relaying networks for MinW relay selection scheme over independent non-identically distributed Rayleigh fading channels, where the eavesdropper node may intercept the source message. To guarantee the quality-of-service of the primary user (PU), both the maximum tolerable peak interference power at the PU and maximum allowable transmit power at secondary users are considered. Relay selection is employed in this paper to improve the secure transmission from secondary source to secondary destination by minimizing instantaneous signal-to-noise ratio at the eavesdropper. For the considered relay selection scheme, we analyze its outage performance and obtain the closed-form lower and upper bounds as well as asymptotic expressions for reliability outage probability (OP) with maximal ratio combining utilized. From the asymptotic expressions, it can be observed that the diversity gain of OP equals to N + 1, where N is the number of secondary destinations. Finally, Monte-Carlo simulations are presented to validate our analysis results.