A prototype underwater acoustic sensor network platform with topology-aware MAC scheme

Underwater Wireless Sensor Networks (UWSNs) can be used in ocean exploration and lake pollution monitoring. They use acoustic media to achieve sensor communications. UWSNs are essentially different from terrestrial RF-based sensor networks due to its highly variable, long propagation delay, and mobility nature. In this paper, we first describe our experimental design of low-cost underwater sensor nodes for deployment in a shallow underwater environment. Then, we propose two UWSN Medium Access Control (MAC) enhancements that can adapt to long acoustic delay: 1) topologyware scheduling scheme to save more energy, and 2) a coordination protocol among neighbours to reduce the frame queuing delay during MAC operations. Our experimental results show the energy efficiency of our UWSN MAC protocol.