An Efficient Distributed Link Selection Scheme for AF-Based Cognitive Selection Relaying Networks

Proposed is a distributed link selection scheme for cognitive selection amplify-and-forward (AF) relaying networks. For such a scheme, by approximating the instantaneous signal-to-noise ratio of dual-hop relaying link by its tight bound, a closed-form outage lower bound expression for the considered system is derived. Also, the average feedback overhead is evaluated. Both analytical and numerical results show that no matter whether the channel state information (CSI) knowledge of the interference links is perfect or not, the proposed scheme incurs extremely low signaling overhead to achieve almost the same outage performance with that of the centralized scheme. In addition, for both schemes, the influence of relay placement on the average feedback overhead is investigated and some useful conclusions are drawn as well.