Analysis and optimization of AF multi-hop over Nakagami-m fading channels in the presence of CCI

In this paper, performance and optimization study of multi-hop wireless system with amplify and forward (AF) relays over Nakagami-m fading channels and in the presence of co-channel interference is considered. Arbitrary number of independent and identically distributed Nakagami-m interferers is assumed in the analysis. The cumulative distribution function (CDF) of the upper bounded end-to-end signal-to-interference-plus-noise ratio (SINR) at the destination is calculated in closed-form. The obtained CDF is then used to study the end-to-end average bit error probability (ABEP). As well, approximate expression for the CDF of the instantaneous end-to-end SINR is derived. Based on this, simple and general asymptotic expression for the error probability is presented and discussed. Finally, optimizing power allocation at the transmit nodes and the positioning of the relays are studied. Obtained results revealed that optimum power allocation slightly enhances the performance, whereas optimizing relay locations yields significant performance enhancement. Further improvement is shown to be achieved through joint power and positions optimization.