Phero-Trail: Bio-inspired Routing in Underwater Sensor Networks∗

A SEA Swarm (Sensor Equipped Aquatic Swarm) moves as a group with water current and enables 4D (space and time) monitoring of local underwater events such as contaminants and intruders. For prompt alert reporting, mobile sensors forward events to mobile sinks (i.e., autonomous underwater vehicles), thus requiring an efficient routing mechanism. In this paper, we analyze various design choices to realize an efficient routing service in a SEA Swarm. We find that conventional ad hoc network routing and location service protocols cannot be directly used. We show that following a phero-trail in a 2D plane is an optimal design choice. We propose a bio-inspired routing mechanism called Phero-Trail. In Phero-Trail, a mobile sink projects its trajectory (like a pheromone trail of ants) on the 2D hull of the SEA Swarm. This enables mobile sensors to efficiently route to a mobile sink via a random walk search. Our preliminarily results show that Phero-Trail performs better than existing approaches.