Energy efficient power allocation and relay location for asymmetric bi-directional relaying

This paper is concerned with energy efficient bidirectional relaying subject to a target quality of service constraint with a special focus on asymmetric system traffics. First, by exploiting the long-term channel knowledge, the optimal power allocation problem with a probabilistic constraint on the system outage probability is solved, resulting in a novel power allocation technique. Then, the combination of the proposed power allocation technique with relay location is investigated to further reduce the system power consumption, leading to a joint power allocation and relay location algorithm. Simulation results show that our proposed algorithm can significantly reduce the system power consumption, while ensuring the required quality of service of the system.