Outage performance and location optimization for traffic-aware two-way Relaying with direct link

In this paper, we investigate the outage performance of a traffic-aware two-way relay system with active direct link by employing three-phase (3P) analog network coding (ANC) under Nakagami-m fading. We derive a tight expression for overall outage probability (OOP) that jointly takes into account the asymmetric traffic requirements at the two end users. We also derive an asymptotic outage behavior in the high signal-to-noise ratio (SNR) regime that characterizes the system diversity order. Further, we address an optimization problem for relay location to minimize OOP of the considered system. Our results demonstrate that optimal relay location has a critical impact on the OOP performance for given traffic requirements. Above all, depending upon the quality of direct link, we show that the traffic-aware 3P ANC can achieve better performance than its two-phase (2P) counterpart, even in the low SNR regime.