Real-time software-defined free-space optical communication system

Abstract

Next-generation software-defined free-space optical (FSO) communication systems may substitute many conventional radio communication systems. The conventional single-purpose dedicated hardware resources in the telecommunication systems have significant limitations since they provide a single communication service using a specific standard at a time. It is also expensive to upgrade to the emerging new standards such as 5G New Radio (5GNR) by substituting the existing hardware resources. Reprogrammable FPGA-based Software Defined Radio (SDR) technology is deployed as a feasible solution to this problem since they can be reconfigured simultaneously realizing the user requirements. When integrated with the FSO system it opens a plethora of opportunities since the Visible Light Frequency Spectrum is barely occupied by the existing technologies and can be designed cost-effectively for the vast bandwidth it has to offer. In this thesis work, we implemented a real-time FSO communication system using an SDR platform. A fully-functional optical communication link has been accomplished using the Universal Software Radio Peripheral (USRP), MATLAB-Simulink communication toolbox and hardware support package, Laser diode, and a Photodetector. We demonstrate successful transmission and reception of baseband signals with very low bit error rate. Visually identical transmitted and received signals also validate the accuracy of the simulation results when compared to those obtained from the real-time FSO-SDR communication system.