Capacity analysis for multi-antenna dual-hop AF system with random co-channel interference

In this work, the performance of a dual-hop amplify-and-forward (AF) multi-antenna relaying system over Rayleigh fading channels with random co-channel interference (CCI) is investigated. Three receiving strategies such as the maximal-ratio combining (MRC), zero-forcing (ZF) and minimum mean square error (MMSE) are employed in the relay to mitigate the impact of CCI which follows a Poisson point process. In second hop, the relay forwards the signal to the destination by using maximum ratio transmission (MRT). Specifically, we derive the asymptotic expressions of the capacities for this system. The simulation and analytical results show that the MMSE/MRT scheme always provides significant improvement on capacity compared with MRC/MRT and ZF/MRT schemes. Furthermore, the MRC/MRT scheme gives almost the same performance as the MMSE/MRT scheme when the density of CCI sources is high.