Exact outage probability of cognitive two-way relaying scheme with opportunistic relay selection under interference constraint

In this study, the authors analyse the outage performance of a cognitive two-way relaying system under an interference constraint. In the proposed protocol, the best relay which is chosen by an opportunistic relay selection strategy, combines the received packets using XOR operation and then forwards the combined packet to two secondary sources. The authors derive an exact closed-form expression of outage probability over flat and block Rayleigh fading channels. Various Monte-Carlo simulations are presented to verify the theoretical analyses and to compare the performance of the proposed protocol with that of the two-way relaying protocol without network coding.