Design guidelines for opportunistic routing in underwater networks

The unique characteristics of the underwater acoustic channel impose many challenges that limit the utilization of underwater sensor networks. In this context, opportunistic routing, which has been extensively investigated in terrestrial wireless ad hoc network scenarios, has greater potential for mitigating drawbacks from underwater acoustic communication and improving network performance. In this work, we discuss the two main building blocks for the design of opportunistic routing protocols for underwater sensor networks: candidate set selection and candidate coordination procedures. We propose classifying candidate set selection procedures into sender-side, receiver-side, and hybrid approaches, and candidate coordination procedures into timer-based and control-packet-based approaches. Based on this classification, we discuss particular characteristics of each approach and how they relate to underwater acoustic communication. Furthermore, we argue that those characteristics should be considered during the design of opportunistic routing protocols for different scenarios in underwater sensor networks.