Efficient depth-based scheduling MAC protoco for underwater sensor networks

Underwater Sensor Networks (UWSN) utilise acoustic waves with comparatively lower loss and longer range in underwater environment than electromagnetic waves. However, energy remains a challenging issue in addition to long latency, high bit error rate, and limited bandwidth. Thus, collision and retransmission should be efficiently handled at MAC layer in order to reduce the energy cost and also to improve the throughput and fairness across the network. In this paper, we therefore propose a new reservation-based distributed MAC protocol, which employs a duty cycle mechanism to address the spatial-temporal uncertainty and the hidden node problem to effectively reduce collisions and retransmissions. Our extensive simulation study reveals that our proposed protocol can efficiently handle the traffic contention to achieve significant improvement in terms of energy consumption, throughput, and fairness.