Outage Performance of Scheduling in a Distributed Multiuser Fixed-gain AF relay System with Co-channel Interference and Noise

We study the outage performance of a multiuser (MU) fixed-gain amplify-and-forward (AF) relaying system in the presence of co-channel interference (CCI) and noise. We consider a distributed scenario where the users are not co-located and are affected by dissimilar number of interferers with non-identical average power. A user is scheduled for reception based on quality of the second-hop signal-to-interference plus noise ratio (SH-SINR). We derive analytical and asymptotic expressions for the outage performance with SH-SINR scheduling and show that there is loss in MU diversity. We also note the equivalence of SH-SINR based scheduling and the optimal scheduling scheme which selects the user with the best end-to-end SINR (e2e-SINR). Numerical results verify accuracy of derived expressions and demonstrate the improvement in performance of SH-SINR scheduling over second-hop signal-to-noise ratio (SHSNR) scheduling.