Opportunistic Routing in Underwater Sensor Networks: Potentials, Challenges and Guidelines

Opportunistic routing (OR) has been showed efficient for the harsh and challenging scenarios of underwater wireless sensor networks (UWSNs). This routing paradigm leverages the broadcast nature of wireless communication, for improving data delivery. In contrast to traditional multi-hop routing, OR selects a subset of the neighboring nodes to be the next-hop candidate nodes, in which will participate forwarding data packets towards the destination. Hence, at each hop, a transmitted data packet is lost only if none of the next-hop candidate nodes receives it. Therefore, OR not only improves packet delivery rate, but also reduces network energy consumption since fewer retransmissions will be needed. However, the design of OR protocols for UWSNs is challenging, due to the characteristics of the underwater acoustic channel. For instance, the high and variable delay, multipath propagation, low bandwidth, and high energy consumption render impractical the use of the up to date protocols developed for wireless sensor and mesh networks. In this context, this tutorial gives a comprehensive review of the potentials and challenges of opportunistic routing in underwater sensor networks. In addition, based on an in-deep literature review, this tutorial will provide important guidelines for the design of novel protocols for different scenarios of UWSNs.