Design and Implementation of Super-TDMA: A MAC Protocol Exploiting Large Propagation Delays for Underwater Acoustic Networks

Underwater acoustic networking research often demands the design of protocols and algorithms that enable a wide range of applications. In spite of research efforts over past decades, practical protocol design is still a challenge. We present the design, implementation and testing of Super-TDMA protocol which exploits the large propagation delay in underwater acoustic channels by aligning most of the interference by the unintended messages in time domain. We study practical modem constraints and implement the Super-TDMA protocol on underwater acoustic modem. The inclusion of modem constraints results in the design which can be realized in practice. The optimal packet and time slot lengths are computed which result in maximum utilization of the time slots by minimizing the guard times. The time synchronization among the nodes using the ranging functionality of the modem is presented. Both analytical and simulation results are presented to show that the practical model used results in significant changes in design of the MAC protocol to be implemented on underwater acoustic modem.