LTM-MAC: A location-based TDMA MAC protocol for mobile underwater networks

Recently underwater acoustic sensor networks with autonomous underwater vehicles (AUVs) have been applied in various areas, such as ocean data collection, marine environment monitoring and military surveillance, which static networks can hardly accomplish. In order to achieve the missions, effective communication is crucial and needs the guarantee of medium access control (MAC) protocol, which schedules nodes' transmissions over the shared medium. In this paper, a location-based TDMA MAC (LTM-MAC) protocol is proposed for singlehop networks with AUVs. LTM-MAC focuses on the occasion where several static nodes and one or two AUVs coexist in the network. The AUVs must send urgent commands as soon as possible and collect data from nodes if necessary. Timely access of AUVs will be the major concern. Simulations show that LTM-MAC outperforms FAMA, a contention-based MAC protocol in throughput, energy efficiency and AUV's access time, which is the focus of attention.