Multi-cluster protocol for ad hoc mobile underwater acoustic networks

An autonomous network of underwater vehicles is considered in which there is no central node, but the vehicles communicate in a distributed manner over multiple hops. The focus of network design is on a scalable multiple access technique which is applicable to varying coverage areas as well as varying number of vehicles. The proposed scheme relies on grouping the adjacent vehicles into clusters, and using time-division multiple access within each cluster. Interference among clusters is managed by assigning different spreading codes to adjacent clusters, while scalability is achieved by spatial reuse of the codes. Network operation begins with an initialization phase, and moves on to continuous maintenance during which mobility is managed. Performance is quantified through measures of connectivity, successful transmission rate, average delay and energy consumption. Simulation analysis is used to obtain optimal cluster size and transmission power for a network with given density of vehicles.