Adaptive Power Allocation in Two-Way Amplify-and-Forward Relay Networks

Two-way amplify-and-forward relaying is considered in this paper. We propose adaptive power allocation (PA) algorithms to maximize the instantaneous achievable rate and minimize the system outage probability, respectively. Both single- and multi-relay systems are considered. It is shown that the proposed adaptive PA algorithms significantly outperform the uniform PA algorithms. Furthermore, exploiting multiple relays obtains higher diversity order and lower outage probability than using only one relay, at the price of a lower achievable information rate. The relay locations and relay selection are also taken into account to further improve the system performance.