Power Allocation Strategies in Block-Fading Two-Way Relay Networks

This paper aims at investigating the superiority of power allocation strategies, based on calculus of variations in a point-to-point two-way relay-assisted channel incorporating the amplify and forward strategy. Single and multilayer coding strategies for two cases of having and not having the channel state information (CSI) at the transmitters are studied, respectively. Using the notion of calculus of variations, the optimum power allocation strategy across code layers for the case of employing Multilayer coding is derived and is shown to surpass the conventional outage approach employing single layer coding strategy in terms of the achievable sum rate of the network. Moreover, for the case of knowing the CSI at the transmitters, an adaptive power control strategy is analytically derived, and its achievable sum-rate is compared to that of the single-layer strategy under peak power constraint.