Joint relay selection and power allocation for cooperative communication over frequency selective fading channels

In this paper, we consider the joint problem of relay selection and optimal power allocation for multi-relay amplify-and-forward (AF) cooperative communication system over frequency selective fading channels. An optimization model combined relay selection and power allocation under a total transmission power budget is formulated. Then, this combinatorial problem is solved in a distributed strategy. Relay selection with a new threshold- based multiple-relay selection (MRS) scheme is implemented at first, and then power is allocated between source and the selected relays in an optimized way to maximize channel capacity. Simulation result shows that the proposed joint scenario with relay selection and power allocation achieves better throughput performance than that of parallel-relay scenario (means that random relay is selected to forward data and allocated part of total power on average). Furthermore, the performances of the new MRS scheme and other relay selection strategies are also investigated.