Joint Relay Selection and Power Allocation in Cooperative-Diversity System

In this paper, we propose two novel algorithms where relay selection and power allocation are jointly considered in order to optimize ergodic capacity in AF (Amplify-and-forward) cooperative diversity communication. In S-AR algorithm, joint power allocation and relay selection is performed to maximize the received SNR at the destination node. In S-OR algorithm, the best relay with maximal instantaneous channel gain is selected at first, and then power is allocated between source and the relay in an optimized way to maximize ergodic capacity. Through Monte Carlo simulation, a conclusion can be drawn that such selective-relay scenarios with joint power allocation have better throughput performance than that of parallel-relay scenario. Furthermore, S-AR algorithm is better than S-OR algorithm when throughput of the cooperative-diversity system is considered.