Balancing Buffer-Aided Relay Selection for Cooperative Relaying Systems

In this paper, we propose a relay selection scheme for buffer-aided cooperative relay networks. The proposed scheme exploits the channel state information and the buffer state information to minimize the outage probability. To achieve that, it constantly seeks to maintain the states of the buffers by balancing the arrival and departure rates at each relay's buffer. More specifically, the half-full buffer state is used as a reference to monitor the state of balance, where a relay's buffer is considered balanced if its arrival and departure rates are equal. In each time slot, among all links that are available for selection, the one that can enhance the balance status of the most unbalanced buffer is selected. The outage probability performances in independent and identically distributed and independent and nonidentically distributed Rayleigh fading channels are investigated. In terms of outage probability, simulation results show that the proposed scheme significantly outperforms the max-link scheme and achieves some improvement compared to the buffer-state-based scheme.