Medium access control layer for underwater sensor networks

There is increasing interest in underwater sensor networks (USNs). Different from terrestrial radio-based sensor networks, communication in underwater sensor networks relies on acoustic signals. Acoustic signals have a propagation speed that is around five orders of magnitude slower than radio signals. Meanwhile, featured by the bandwidth limitations, high transmit energy cost, complex multi-path effects, and high bit-error rates, medium access control (MAC) with an acoustic medium in USNs becomes a complex and challenging problem. In this chapter, we discuss various MAC protocols that are designed for short-range acoustic underwater sensor networks, energy-efficient reliable MAC protocol, and slotted floor acquisition multiple access (FAMA) MAC protocol and low-power acoustic modem for dense underwater sensor networks.