Outage Analysis of Multi-Relay Selection for Cognitive Radio with Imperfect Spectrum Sensing

TL;DR

This paper analyzes the outage performance of a cognitive relay network with multiple relays and imperfect spectrum sensing, proposing a multi-relay selection scheme that outperforms traditional methods in Rayleigh fading environments.

Contribution

It introduces a novel multi-relay selection scheme for cognitive radio networks and derives a closed-form outage probability expression considering imperfect spectrum sensing.

Findings

Multi-relay selection reduces outage probability compared to benchmarks.

Improved spectrum sensing enhances network reliability.

Proposed scheme outperforms direct and best-relay selection methods.

Abstract

In this paper, we examine the outage performance of a cognitive relay network, which is comprised of a secondary transmitter (ST), multiple decode-and-forward (DF) relays and a secondary destination (SD). We propose a multi-relay selection scheme for the cognitive relay network, where multiple relays are selected and used to participate in forwarding the secondary transmission from ST to SD. A closed-form expression of the outage probability for the proposed multi-relay selection under imperfect spectrum sensing is derived in Rayleigh fading environments. For comparison purposes, the conventional direct transmission and the best-relay selection are also considered as benchmarks. Numerical results show that as the spectrum sensing performance improves with an increasing detection probability and/or a decreasing false alarm probability, the outage probabilities of the proposed multi-relay selection as well as the direct transmission and the best-relay selection schemes all decrease accordingly. It is also demonstrated that the proposed multi-relay selection significantly outperforms the conventional approaches in terms of the outage probability.