Performance Optimization of FSO link via Intelligent Reflecting Surfaces (IRS)

In order to create a connection in a specific remote area of a skip zone where an optical fiber cable or wireline solution is difficult to build, free space optics (FSO) is essential. For 5G and future transmission networks, FSO connection has been selected as a potential option for secure, low-latency, license-free spectrum and less costly wireless backhaul connectivity. The main obstructions to FSO transmission are adverse weather conditions as well as the need for a direct line of sight (LoS) from Source to Destination. An innovative approach termed intelligent reflecting surface (IRS) based FSO transmission is a most reliable and efficient interesting approach, similar to first-last mile access connection, to relax the line of sight condition of FSO transmission. In this study, IRS-assisted radio frequency (RF), as well as optical IRS-assisted FSO connections are modeled. The FSO link via the IRS module achieves 10–6 value of symbol error rate (SER) at 30 dB SNR while the FSO link without IRS module achieves only 10–3 and 10–2 values of SER at the same SNR for the FSO link is modeled with Gamma-gamma and generalised Malaga (M) distributions, respectively. The SER value is enhanced up to a factor of 10–8 at 20 dB SNR in case of multiple optical-IRS-based FSO connections by increasing additional reflecting elements module (N).