Stochastic Modeling of Opportunistic Routing in Multi-Modal Internet of Underwater Things

Internet of Underwater Things (IoUT) has gained increased attention as an envisioned technology for supporting smart ocean applications. However, the harsh aquatic environment and challenges of underwater acoustic communication still severely limit data collection in underwater networks and IoUT applications. In recent years, programmable physical layer and multi-modal communication for IoUT have been proposed to improve the performance of underwater networks. However, several fundamental challenges need yet to be investigated and tackled, in order to achieve efficient data collection in IoUT. One of the daunting fundamental challenge to be solved is the design of innovative routing protocols for multi-modal IoUT. In this paper, we propose a mathematical model for the study of opportunistic routing (OR) in multi-modal IoUT. The devised mathematical framework models the unique characteristics of OR in multi-modal IoUT scenarios, while considering the peculiar characteristics of the underwater environment and acoustic communication. Moreover, we propose a candidate set selection procedure of OR, which jointly selects the acoustic modem and next-hop forwarder candidate nodes at each hop, to increase data delivery. Numerical results showed the potential of multimodal communication for improving data delivery in the harsh environment of underwater acoustic communication.