Last mile access-based FSO and VLC systems

Abstract

Free-space optics (FSO) and visible light communication (VLC) are interesting solutions for last mile access due to their benefits over conventional wired and wireless communication systems, including easy installation, low latency, high bandwidth, and low cost. This study aims to present last mile access using hybrid FSO/VLC, addressing the shortcomings of each technology. A hybrid system might, for instance, use VLC to give last meter connectivity to specific buildings and FSO to provide high-bandwidth outdoor connectivity across vast distances. In this paper, three proposed scenarios are designed using Optisystem and Matlab software, employing pulse amplitude modulation with four levels (PAM-4). The first scenario involves designing the last mile of the FSO-VLC system. In contrast, the second uses wavelength division multiplexing (WDM) technology to increase the data transmission capacity by enabling multiple optical signals at various wavelengths. The last scenario entails using VLC systems and the non-orthogonal multiple access (NOMA) approach to accommodate several users simultaneously. The simulation results show that the proposed system can fulfill outdoor link distances of more than 10 km and indoor coverage of about 2 m with a bit-error rate (BER) of 1.5×10−32 for a 10 Gbps data rate. However, the proposed systems can achieve the same data rate with a reduced FSO distance under different turbulence and weather conditions.