Prospects and Problems of Optical Diffuse Wireless Communication for Underwater Wireless Sensor Networks (UWSNs)

The aim of this paper is to highlight the prospects and problems of optical wireless communication for applications in the field of Underwater Wireless Sensor Networks (UWSNs). The necessity of wireless underwater connections, especially in UWSN, has dramatically increased in the last few years for a wide range of applications, from environmental monitoring to surveillance. The problem of wireless underwater communication is a challenging field of investigation since common terrestrial devices, equipped with radio wireless links, cannot be employed underwater and current underwater available technologies, mainly based on acoustical solutions, still pose problems due to low propagation speed of sound in water and low data-rate. In the last years, the interest towards optical wireless communication has increased both for terrestrial (Akella et al., 2005) than for underwater applications (Doniec et al., 2010) since it allows to overcome some of the problems of acoustical communication (Akyildiz et al., 2005). In fact low data rate and low propagation speed require specific solutions and make it difficult the integration of underwater technologies with current available terrestrial modules. Transferring the paradigm of Smart Dust (V. Hsu & Pister, 1998) to UWSNs, largely unaffected byWSN revolution, is a challenge that can open great opportunities since current underwater solutions are still of large dimension, expensive and power-consuming.