Power Allocation for Two-Way Opportunistic Amplify-and-Forward Relaying over Nakagami-m Channels

We are concerned with transmit power optimization for two-way opportunistic relaying (TWOR) systems in amplify-and-forward (AF) strategy over independent and non-identically distributed (i.ni.d.) Nakagami-m fading channels. With instantaneous squared channel strength known to source nodes before transmitting, we derive an optimum power allocation (OPA) scheme by solving an optimization problem of signal-to-noise ratio (SNR) balancing. While with only statistical channel knowledge, we propose a sub-OPA scheme that minimizes the high-SNR approximation of the system outage probability. Simulation results show that the proposed schemes significantly outperform the equal power allocation (EPA) scheme available in outage probability.