Performance Analysis of Fixed Gain Relay Systems With a Single Interferer in Nakagami- $m$ Fading Channels

We investigate the outage probability and average bit error rate (BER) of a dual-hop fixed gain relaying system in the presence of interference and noise at the relay and destination. Our analysis assumes Nakagami-m fading for the source-relay, relay-destination, and interfering channels. We present new closed-form/series expressions for the outage probability, as well as the average BER. It is concluded that the presence of interference results in a floor point in both outage and BER performance. This floor point holds for signal-to-noise ratio (SNR) values higher than a certain threshold such that the larger the difference between the received powers of the useful and interfering signals, the higher the SNR value at which this floor point commences. Moreover, it is shown that the performance is practically not affected by the Nakagami-m shape parameter of the fading at the interfering link.