A novel architecture for multi-hops routing ad hoc underwater acoustic sensor networking

Underwater acoustic communication ad-hoc networks are an innovative issue, which faces difficult medium problems, such as long propagation time and dynamic network topology. In addition, due to high error probabilities typical for this channel it is preferred to use collision free mechanism. Because of the long propagation time, protocols such as MACA, requiring transmissions of pre-messages, achieve relatively low network efficiency. Moreover, TDMA scheme do not utilize the network resources allowing reuse in the code domain (using CDMA) and spatial reuse when possible. In this paper we introduce an underwater acoustic adhoc network consist of multi-hop relays and supports quality of service such as network reliability, minimum latency and priority. The network concept is based on CDMA confronting the acoustic underwater network challenges, such as the "near-far" problem and fast time varying topology. Using this concept, a sea trial including broadcast, multicast and unicast transmissions of SMS and navigation messages was carried out in various scenarios including multi-hops near the shores of Israel. We present results from this sea trial demonstrating the efficacy of the proposed networking scheme.