Reflection assisted beam propagation model for obstructed line-of-sight FSO links

摘要

A non-line-of-sight (NLOS) infra-red reflection based beam propagation model is proposed as a supplement to conventional terrestrial free space optical (FSO) communication system. This ray propagation model lets tactically positioned optical reflectors to smartly exploit the aggregated advantages of mirror characteristics to bridge the existent communication gap between two FSO nodes due to inclined or obstructed line-of-sight view. Additionally, a numerical framework of the proposed system is presented that analytically explores the optical losses induced by harmonic distortions and the resultant beam divergence at the receiver. The impact of the different reflectors on the traversing beam is then investigated through an experimental FSO test-bed set in an outdoor environment in terms of phase shifts, divergence loss, noise margin and maximum achievable link length. Matlab based simulations, based on the experimental outcomes, envisages that concave reflectors can effectively compensate the turbulence induced signal fading and restrict the beam divergence loss; thereby, improving the maximum achievable NLOS FSO link length.