Characterization of Aloha in underwater wireless networks

This paper provides an analytic framework of Aloha and slotted Aloha (S-Aloha) performance in an underwater one-to-one communication environment with high and random inter-nodal signal propagation delay. The analysis shows that random inter-nodal propagation delay has no effect on the underwater Aloha performance. It also sheds light on the throughput degradation of underwater S-Aloha with a slotting concept that achieves terrestrial S-Aloha equivalent one-slot vulnerability. Additionally, a new, modified slotting concept is introduced where the slot size is judiciously reduced such that even by allowing some collisions the overall system throughput can be increased. Our numerical and simulation results show that, with the modified slotting approach up to 17% throughput performance gain can be achieved over the naive (terrestrial S-Aloha equivalent) slotting approach.