Opportunistic dual timer relay selection in MIMO relay networks

In this paper, we investigate opportunistic buffer-equipped, multi-antenna relay networks with a decode-and-forward relaying strategy. The channel that we are considering includes three key wireless channel effects: path loss, shadowing, and fast fading. We first analyze the direct communication outage probability, and based on that, analyze the opportunistic relay network´s outage probability. For an opportunistic relay selection protocol, we consider max-max relay selection (MMRS), where two relays are involved in the relaying: one for the source data reception and the other for transmission to the destination. As a relay selection method, we suggest dual-timer relay selection (DTRS), which reduces channel estimation overhead and solves the full-buffer problem of a reception relay and the empty-buffer problem of a transmission relay in the MMRS protocol. Along with the DTRS protocol, we further investigate the optimal relay selection period for maximizing the throughput while avoiding selection overhead.