Investigation on localization Algorithms and multicarrier Modulation for performance Improvement of acoustic optical underwater sensor nodes in Coastal water environment

Abstract

Underwater Wireless Sensor Networks (UWSNs) involves the interaction, coordination and information exchange between nodes that are deployed in the ocean environment, in order to carry out sensing and monitoring functions. Acoustic waves have been the practical way to communicate under water, for long distances. However, they suffer from very low-speed and low energy efficiency communications, when compared to current standards. Since the RF spectrum is limited and expensive, emerging alternative approach is Optical Wireless Communication (OWC), which offers many advantages over RF transmission with a high-capacity. Because of the availability of a huge license-free spectrum of approximately 670 THz, OWC has the potential to provide wireless links with very high data rates. newlineIn a large scale underwater wireless sensor network, it is essential that numerous sensor nodes have to be deployed and precisely localized in a 3D underwater environment for wide coverage and good connectivity of the network. Improvement of performance of the Sensor nodes will lead to improvement in performance of the overall Network. newlinePerformance of the sensor nodes are defined in terms of the following: newlineand#61623; Improved energy efficiency for data processing and data transmission during localization and communication process. In consideration of the high power of underwater acoustic modems and the difficulties in changing sensor nodes because of the harsh environment, the energy efficiency in UASN is even more vital. newline