Effective Relay Selection for Underwater Cooperative Acoustic Networks

Cooperative communication has been studied extensively as a promising technique for improving the performance of terrestrial wireless networks. However, in underwater cooperative acoustic networks, long propagation delays and complex acoustic channels make the conventional relay selection schemes designed for terrestrial wireless networks inefficient. In this paper, we develop a new best relay selection criterion, called COoperative Best Relay Assessment (COBRA), for underwater cooperative acoustic networks to minimize the one-way packet transmission time. The new criterion takes into account both the spectral efficiency and the underwater long propagation delay to improve the overall throughput performance of the network with energy constraint. A best relay selection algorithm is also proposed based on COBRA criterion. This algorithm only requires the channel statistical information instead of the instantaneous channel state. Our simulation results show a significant decrease on one-way packet transmission time with COBRA. The throughput and delivery ratio performance improvement further verifies the advantages of our proposed criterion over the conventional channel state based algorithms.