Non-line-of-sight optical wireless sensor network operating in multiscattering channel.

Networks of sensors are envisaged to be major participants in future data-gathering systems for civilian and military applications, including medical and environmental monitoring and surveillance, home security, agriculture, and industry. Typically, a very large number of miniature sensing and communicating nodes are distributed ad hoc at the location of interest, where they establish a network and wirelessly communicate sensed data either to one another or to a base station using various network topologies. The optical modality is a potential solution for the links, due to the small and lightweight hardware and low power consumption, as well as other special features. Notably, the backscattering of light by molecules and aerosols in the atmosphere can function as a vehicle of communication in a way similar to the deployment of numerous tiny reflecting mirrors. The scattering of light at solar-blind ultraviolet wavelengths is of particular interest since scattering by atmospheric particles is significant and ambient solar interference is minimal. In this paper we derive a mathematical model of a simple and low-cost non-line-of-sight (NLOS) optical wireless sensor network operating in the solar-blind ultraviolet spectral range. The viability and limitations of the internode link are evaluated and found to facilitate miniature operational sensor networks.