Enhanced Spectrum Slicing--Wavelength Division Multiplexing Approach for Mitigating Atmospheric Attenuation in Optical Communication

Over the last decades, free-space optics (FSO) emerged as a prominent way of communication over radio frequency communication and microwave communication. Working of FSO in comparison with optical fiber cable (OFC) network is the same. The only difference between FSO & OFC is the transmission of an optical beam. The optical beam is transmitted through the free space in the case of FSO. Whereas the transmission of optical beam takes place using OFC core, i.e. glass fiber in the case of OFC. Fog, haze, rain, and clouds in the atmosphere directly affect FSO performance and the power of signal propagation. Further added, the wavelength of propagating beam is based on the size of fog particles which leads to atmospheric attenuation. To mitigate the impact of atmospheric attenuation on signals, the proposed study is based on a spectrum slicing (SS) - wavelength division multiplexing (WDM) system with Pre and Post Amplification. The analysis of SS-WDM-Pre and SS-WDM-Post has been done over various values of attenuation. The comparison analysis proves that the SS-WDM-Post is more efficient than both SS-WDM-Pre and traditional SS-WDM in terms of Q-factor.

Spectrum Slicing for Multiple Access Channels with Heterogeneous Services

Wireless mobile networks from the fifth generation (5G) and beyond serve as platforms for flexible support of heterogeneous traffic types with diverse performance requirements. In particular, the broadband services aim for the traditional rate optimization, while the time-sensitive services aim for the optimization of latency and reliability, and some novel metrics such as Age of Information (AoI). In such settings, the key question is the one of spectrum slicing: how these services share the same chunk of available spectrum while meeting the heterogeneous requirements. In this work we investigated the two canonical frameworks for spectrum sharing, Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA), in a simple, but insightful setup with a single time-slotted shared frequency channel, involving one broadband user, aiming to maximize throughput and using packet-level coding to protect its transmissions from noise and interference, and several intermittent users, aiming to either to improve their latency-reliability performance or to minimize their AoI. We analytically assessed the performances of Time Division Multiple Access (TDMA) and ALOHA-based schemes in both OMA and NOMA frameworks by deriving their Pareto regions and the corresponding optimal values of their parameters. Our results show that NOMA can outperform traditional OMA in latency-reliability oriented systems in most conditions, but OMA performs slightly better in age-oriented systems.