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LT-MAC: A location-based TDMA MAC protocol for small-scale underwater sensor networks

Because of the high attenuation, sound is mainly used as the communication medium in underwater sensor networks instead of light or microwave. MAC protocols designed for radio networks aren't suitable for acoustic channels which feature long propagation delay and limited bandwidth. In this paper, we propose a location-based MAC protocol, called LT-MAC. LT-MAC dynamically determines each node's sending time according to the variable offered load, and assigns the time slot to each node based on the minimum waiting time rule. In addition, the protocol combines sending and acknowledgement to overcome low throughput and long end-to-end delay problems. By theoretical analysis and simulation, we show that LT-MAC is a comparatively good solution for single-hop and small-scale underwater sensor networks.