Implementation of forward error correction for improved performance of free space optical communication channel in adverse atmospheric conditions
Srinivasa Narayanan, B. C. Dhanush Devappa, Kalyani Pawar, S. Jain, Appala Venkata Ramana Murthy
Abstract
The tremendous speed and security that Free Space Optical Communication (FSOC) technology provides have led to its rapid expansion. This opens up a plethora of possibilities for terrestrial communication with small ranges of up to a few kilometers, such as multi-campus and building-to-building communication. However, the ever-varying nature of atmospheric channels poses a major challenge degrading the optical signal strength. Several constituents of atmospheric channels like fog, dust, smoke, rain, and wind turbulence will influence the performance of an FSOC channel. In this paper, we present a system model focusing on adverse atmospheric channels, primarily by replicating varying fog conditions. Additionally, we showcase the successful real-time implementation of diverse forward error correction (FEC) codes in adverse atmospheric conditions, specifically varying levels of fog, using a dedicated test bed. Our experiments demonstrate the capability to recover erroneous data up to 50% Bit Error Rates (BER). Furthermore, we delve into the selection of suitable FEC codes tailored to different fog conditions, aiming to optimize time efficiency with the encoded bitrate.