Field Experiment and Analysis of Underwater String Networks Based on PMAC

Underwater Wireless Sensor Networks (UWSNs) have attracted widespread attention from academia and industry over several years, and several network architectures and protocols have been proposed. Due to the limited test resource and harsh underwater communication environments, it is very challenging for current simulators to analyze network performance under different protocols, when compared to field tests. This paper presents field experiments performed in Fuxian Lake, Daya Bay and the Yellow Sea, respectively, to evaluate the achievable network performance. In the above tests, the underwater nodes were deployed as string topologies and accessed to the acoustic channel by Pipelining MAC (PMAC). Nodes deployed three hops away were allowed to transmit simultaneously, by eliminating chances of collisions and parallelizing transmissions. These experiments verify the effectiveness of our deployment schedules in terms of network performance. Furthermore, we discuss the applications of underwater string networks in oceanographical data collection as well as in medium and long-distance control.