Opportunistic Adaptive Relaying in Cognitive Radio Networks

TL;DR

This paper introduces an adaptive relaying scheme for cognitive radio networks that improves secondary transmission reliability by intelligently assisting primary or secondary signals, with derived bounds and simulation validation.

Contribution

It proposes a novel adaptive relaying scheme for cognitive radio networks, including an extension for simultaneous assistance, with analytical bounds and performance evaluations.

Findings

Lower secondary outage probability compared to existing schemes

Performance gains from the extension with simultaneous assistance

Analytical bounds derived for Rayleigh fading channels

Abstract

Combining cognitive radio technology with user cooperation could be advantageous to both primary and secondary transmissions. In this paper, we propose a first relaying scheme for cognitive radio networks (called "Adaptive relaying scheme 1"), where one relay node can assist the primary or the secondary transmission with the objective of improving the outage probability of the secondary transmission with respect to a primary outage probability threshold. Upper bound expressions of the secondary outage probability using the proposed scheme are derived over Rayleigh fading channels. Numerical and simulation results show that the secondary outage probability using the proposed scheme is lower than that of other relaying schemes. Then, we extend the proposed scheme to the case where the relay node has the ability to decode both the primary and secondary signals and also can assist simultaneously both transmissions. Simulations show the performance improvement that can be obtained due to this extension in terms of secondary outage probability.