Performance of two-way amplify-and-forward relay networks over asymmetric channels

This paper considers a two-way amplify-and-forward (AF) relay network, where two users communicate with each other through an intermediate relay over asymmetric Nakagami-m channels. The average bit-error rate (BER) performance is analyzed for the relay under average power scaling (APS) and instantaneous power scaling (IPS) constraints. We demonstrate that this network operating in two time slots not only improves spectrum efficiency, but also achieves the same BER performance as that working in four time slots under the same total and individual power constraints. Both analytical and simulation results show that a user will have a lower error probability of detecting the other user´s signals if this user has a worse channel condition with the relay. In addition, IPS achieves better performance than APS but costs higher computing load for the relay.