DSP-enhanced dual-polarization PAM-based next-generation free-space optical communication systems for IoT applications

Abstract The rapid growth in wireless communication propelled by fifth-generation (5G) technology has drastically raised the demand for high-bandwidth connections, especially owing to the incorporation of Internet of things (IoT) applications. Conventional radio-frequency (RF) systems, however, are unable to meet these increasing bandwidth demands. In this context, free-space optical (FSO) communication has emerged as a viable alternative in the contemporary high-data rate era, providing substantial bandwidth and an efficient option for last-mile connection. But FSO linkages are particularly vulnerable to atmospheric weather conditions. Here a dual-polarized probabilistic amplitude shaping (PAS) enabled pulse-amplitude-modulated (PAM) FSO system utilizing digital signal processing techniques is proposed. The system’s performance is assessed under diverse meteorological conditions at a data rate of 400 Gbps. The system performance is assessed using bit error rate (BER), received optical power (ROP) and error vector magnitude (EVM). Under clear atmospheric conditions, the system delivers optimal performance with an achievable FSO range of 1,650 m, while the worst performance is observed under fog conditions. Attainable FSO link distance of 700 m, 500 m, and 400 m are attainable in Weak, moderate, and severe fog conditions respectively, while the log(BER) is sustained between −2 and −2.5. The proposed FSO system effectively addresses the bandwidth demands of contemporary IoT integration.