A Peaking Staggering Transmission MAC Protocol for Underwater Acoustic Networks

The underwater acoustic networks (UANs) have the characteristics of long propagation delays and low bit rates. The characteristics above pose significant challenges in UANs media access control (MAC) protocol. Slotted floor acquisition multiple access (S-FAMA) protocol is widely used in UANs. This protocol is based on FAMA, and data packet collisions can be avoided by adding a time slot mechanism. However, S-FAMA is not suitable UANs when the number of nodes is dense and long propagation delays, because this will lead to a low system throughput. To overcome this shortcoming, this paper proposes a protocol based on S-FAMA, called peaking staggering floor acquisition multiple access (PST-FAMA). PST-FAMA introduces a near-far model and makes use of long propagation delays to improve system throughput. First of all, via the near-far model, it can effectively plan the data packet sequence and complete multiple data transmissions when in the situation of dense nodes and long propagation delays. Secondly, PST-FAMA sets a short time slot, and the idle of initiator nodes will be reduced. Simulation results show that comparing with S-FAMA, PST-FAMA improves the system throughput and minimizes the idle time of initiator nodes.