Rate performance of adaptive link selection in buffer-aided cognitive relay networks

We investigate the performance of a two-hop cognitive relay network with a buffered decode and forward (DF) relay. We derive expressions for the rate performance of an adaptive link selection-based buffered relay (ALSBR) scheme with peak power and peak interference constraints on the secondary nodes, and compare its performance with that of conventional unbuffered relay (CUBR) and conventional buffered relay (CBR) schemes. Use of buffered relays with adaptive link selection is shown to be particularly advantageous in underlay cognitive radio networks. The insights developed are of significance to system designers since cognitive radio frameworks are being explored for use in 5G systems. Computer simulation results are presented to demonstrate accuracy of the derived expressions.