CT-TDMA: Efficient TDMA protocol for underwater sensor networks

Aimed at underwater acoustic sensor networks (UWSN), a novel sender based conflict model with the schemes of allocating continuous time was presented, including local conflict graph (LCG) and a distribute algorithm to generate LCG. Moreover, CT-TDMA, an efficient TDMA protocol based on the conflict model was also proposed, which used heuristic priority rules to allocate transmitting moments for all nodes. CT-TDMA exploits the diversity of propagation delay of different links in UWSN to decrease the idle time between packets at the same receiving node, which helps in improving the throughput. And a heuristic schedule algorithm is applied to shorten the process of allocating continuous time for each node. Simulation results show that, compared with traditional TDMA protocols such as ST-MAC, network throughput of CT-TDMA has increased 20% and end to end delay has decreased 18%; compared to the theoretically optimal scheme with global knowledge, CT-TDMA has achieved 80% network throughput and the end to end delay is only 12% longer.