Power and distance based MAC algorithms for underwater acoustic networks

In this paper, we study MAC (Media Access Control) protocols for underwater acoustic networks. Our starting point is the protocol based on the CSMA/CA method. We propose to modify the CSMA/CA in order to increase the protocol performance. The first proposition requires a local knowledge about distance between nodes. If a node knows the distance separating it to the destination, it can adapt the timeout parameter (the time that a node waits for before repeating its request of transmitting) to this distance. In wireless networks the adaptation of this parameter has no interesting influence while in the case of underwater communication, propagation delay is important and so adapting the timeout parameter allows interesting gains in delay and throughput. We propose then to control transmission power in order to decrease probability of collision and energy consumption. Comparison of protocols performance is done in term of available throughput of nodes and delay of transmission. The simulation system model is detailed