PERFORMANCE EVALUATION OF AD-HOC ROUTING PROTOCOLS IN UNDERWATER ACOUSTIC SENSOR NETWORKS

Abstract

Underwater acoustic sensor networks(UWASNs) is an emerging technology, comprising of sensor nodes and unattended automated vehicles (AUVs), all working in a collaboration to sense various phenomenon, process digital information, store processed data and communicate among each other and base stations. UWASNs have the capability and potential of supporting large set of applications ranging from oceanic geographical surveys to tactical surveillance. Underwater Acoustic propagation is characterized by high and variable delays, fading effect, Doppler spread and multi path which in turn lead to a limited bandwidth and high error rates. At the same time, battery life of the sensor nodes and their data storage capacity is limited. So there is a need to find a suitable routing protocol that takes all these limitations into consideration and makes communication in underwater networks viable. In this paper we focus on existing mobile ad-hoc routing protocols which are widely accepted and have been tested across the globe. This is the first attempt to analyze the performance of these protocols in underwater acoustic networks environment. The first challenge is to come up with a reliable simulation environment for underwater networks in ns-2. Currently, ns-2 does not support simulation for underwater networks. We extended ns-2 for underwater networks by adding underwater propagation, network interface (data link layer) and underwater physical models. After having a working underwater networks simulation model, we then proceeded with our study. We used performance metrics like packet delivery ratio, average end-to-end delay, throughput, routing overhead and energy consumption of the sensor nodes. AODV, DSDV, DSR and OLSR are compared for their performance at different traffic conditions, number of nodes and depths. By analyzing our simulation results, 4 we found that AODV is recommended for denser underwater networks but with less traffic. DSDV is suitable for higher traffic conditions with optimal number of nodes.