On the underwater wireless network clustering

In this paper, we consider a two-tier communication scenario in an underwater sensor network. The field nodes form single-hop clusters around the gateway nodes and communicate with them via acoustic wireless links, while the gateway nodes communicate directly via radio frequency (RF) wireless links to the sink node. Thus, the field data is collected at the sink node via two-hop communication links. The field data being sporadic, the multi-access communications in the two hops are considered slotted random access (S-Aloha) based. We first analyze the performance of the receiver synchronized S-Aloha in underwater network which is used for data communication from the sensor nodes to their respective gateway nodes. The multi-access throughput performance over the RF links at the sink node is also characterized. We then study the optimum cluster size that maximizes the overall network throughput. Our numerical results are supported by discrete event based random network simulation studies.