Performance of Multihop Relay Systems in a Rayleigh Fading Environment with Co-Channel Interference

In this paper we investigate the effect of co-channel interference on the performance of multihop transmission systems that employ amplify-and-forward (AF) relays and operate in a Rayleigh fading environment. Using an upper bound for the end-to-end signal-to-interference-and-noise ratio (SINR) which is given by the minimum SINR of all the hops, we derive closed form expressions for the outage probability and the moment generating function (MGF) of the SINR bound. The average symbol error rate of various modulation formats in multihop AF relay systems can then be obtained using the MGF-based approach, whereas closed-form expressions are obtained for the case of binary phase shift keying. The analysis considers relay systems that suffer from the presence of noise and interference as well as interference-limited and noise-limited systems. The accuracy of the analytical results is verified by computer simulation.