Efficient Topology Control and Depth Adjustment Technique for Connectivity in UWSN

In Underwater wireless sensor networks (UWSNs), nodes are moving due to the external parameters like ocean currents and marine organisms etc. The topology control techniques proposed for traditional wireless sensor networks (WSN) were not applicable for UWSN because of its propagation delay, less bandwidth and multipath fading. An Efficient Topology Control and Depth Adjustment (ETDA) technique for UWSN is designed. The major role of ETDA technique is to reduce node disconnections and to improve the link quality of transmission. In this technique, a combined objective function (COF) is defined for topology control based on the energy level of nodes, distance between the nodes at different depth levels and the link expiration time. The topology control algorithm is applied by each sink node when a broken link or poor channel quality is detected at any part of the network. In this algorithm, the sink node performs reconnection to an intermediate sensor node with maximum COF value. Experimental results show the performance improvement of ETDA by maximizing the packet delivery ratio and minimizing the energy consumption and delay.