Performance analysis of interference-limited relay systems over large-scale fading channels

In this paper, we consider an interference-limited dual-hop relay system, in which the overall system performance is governed not by an additive white Gaussian noise (AWGN), but by co-channel interference (CCI), due to aggressive frequency reuse for high spectrum utilization. We consider that the received signal-to-interference power ratio (SIR) at each hop is affected by large-scale fading (path-loss and shadowing) as well as small-scale Rayleigh fading. Assuming that the multiple CCIs in each hop are distributed as a Poisson point process on the infinite plane, we investigate the outage performance of the AF and DF relay systems. In order to analyze the performance of AF relaying, we exploit the upper and lower bounds, which can be directly obtained from the outage probability of the DF relay system. Even though the closed-form expression for the outage probability of the DF relaying cannot be found, the results can be obtained by simple numerical method, requiring only one integration calculus. For the various propagation parameters and interferer density, we present how the CCIs influence on the outage performance of dual-hop relay systems, and show that the performance gap between the upper and lower bounds is not significant.