Towards last-mile connectivity in 6G-IoT: An integrated MIMO-FSO communication system and FBG sensors under atmospheric attenuations, strain and temperature effects

Abstract

Free-space optical (FSO) communication is an advanced wireless optical communication technology that provides high-speed data services for 6th-generation wireless communication and Internet of Things (IoT) networks. In light of developing a 6G IoT network in an open environment, this paper analyses the impact of temperature and strain on FSO communication links using Fiber Bragg Grating (FBG) sensors. FSO systems are sensitive to temperature variations, and the position of the receiving telescope can be altered by mechanical strain that can affect the refractive index of the atmosphere, leading to signal attenuation and pointing errors. The current work proposes a model that integrates FBG sensors with an FSO channel for simultaneous strain and temperature measurements and a compensator that overcomes severe signal attenuations. Also, the impact of atmospheric attenuations on FSO systems is analysed. Scintillation models for weak, moderate and strong turbulence conditions are analysed, and the performance of the gamma-gamma turbulence model has been used to observe the MIMO FSO channel. The results are observed for FSO links with the atmospheric attenuations with FBG sensors that reflect the pointing errors at the receiver, showing a comprehensive ability to capture strain and temperature parameters. For the transmission of 10 Gb/s data, it was observed that the inclusion of the Multiple input and multiple-output (MIMO)-FSO technique significantly reduces bit errors from −3.12494 dB to −35.018 dB and increase signal power from 52.4 dBm to 58.9 dBm, indicating the adaptability of this integrated strategy for FSO communication with FBG sensors for last mile connectivity in 6G-IoT applications.