Spectral segmentation-based RoFSO-channel’s mixed-RF-signal demodulation technique for the outdoor-optical 6G era network

Abstract

The worldwide communication industries are in urgent need of sixth-generation (6G) technology to meet the near-future terrestrial/space/deep-space data-rate/bandwidth requirements to provide the expected/demanded internet of everything (IoE) services. The ultra-broadband mixed-RF-signal transportation over the free-space optical (FSO) channel, i.e., RoFSO, is a potential and emerging candidate to fulfill the requirements of the near-future 6G era. The effective modulation and demodulation of a mixed-RF-signal to/from the RoFSO-channel is a primary requirement for the successful implementation of RoFSO schemes in 6G. An accurate spectral detection technique is proposed in this work in order to demodulate the transmitted mixed-RF signal over time. The proposed technique is validated using a 6 km RoFSO test-bed, and the results obtained from the different trials are reported. The results taped-out from the starting, intermediate, and the final stages of the proposed technique demonstrate the capability/accuracy of the proposed technique for the purpose of accurately demodulating the mixed-RF-signal from the RoFSO-channel. The measured correlation between the transmitted and received mixed-RF-signal is 100%, which proves the accuracy of the proposed demodulation technique. Furthermore, some recent research and challenges pointed out that RoFSO is mandatory for the implementation of advanced 6G-based applications such as undersea communication, space/deep-space FSO communication, quantum communications, secured wireless network for IoE applications, and multi-hop relay-based RoFSO satellite links.