A Comparison of Multiple Access Techniques in Clustered Underwater Acoustic Networks

In this paper, we carry out an extensive performance evaluation of multiple access schemes applied to clustered UnderWater Acoustic Sensor Networks (UWASN). Networking underwater sensors poses new and interesting issues with respect to radio environments, as they require to account for unusual channel behaviors, such as large propagation delays, higher energy consumption during transmission as compared to reception, distance-varying available acoustic bandwidth, strong fading phenomena, and so on. In particular, managing channel access in converge-casting scenarios is difficult, as many nodes have to share the same medium under the previously cited contraints, in order to report to the same data collecting station. To this aim, we organize the network in clusters and give details on which access scheme (both for the clusterheads and for the children nodes) gives better results under a number of performance metrics, highlighting the different protocol behaviors in the scenarios of interest and translating the relevant tradeoffs into design criteria.