MIMO CDMA-based Optical SATCOMs: A New Solution

TL;DR

This paper introduces a novel MIMO CDMA-based optical satellite communication scheme that optimizes pulse width for terrestrial fiber links and employs adaptive beam-forming for satellite links, addressing interference and fading issues.

Contribution

It presents a comprehensive optimization framework for uplink and downlink in optical SATCOMs, including pulse-width optimization and robust beam-forming solutions under fading and interference.

Findings

Optimized pulse-width reduces fiber dispersion effects.

Adaptive beam-forming enhances satellite link robustness.

Analytical results demonstrate improved system performance.

Abstract

A new scheme for MIMO CDMA-based optical satellite communications (OSATCOMs) is presented. Three independent problems are described for up-link and down- link in terms of two distinguished optimization problems. At first, in up-link, Pulse-width optimization is proposed to reduce dispersions over fibers as the terrestrial part. This is performed for return-to-zero (RZ) modulation that is supposed to be used as an example in here. This is carried out by solving the first optimization problem, while minimizing the probability of overlapping for the Gaussian pulses that are used to produce RZ. Some constraints are assumed such as a threshold for the peak-to-average power ratio (PAPR). In down-link, the second and the third problems are discussed as follows, jointly as a closed-form solution. Solving the second optimization problem, an objective function is obtained, namely the MIMO CDMA-based satellite weight-matrix as a conventional adaptive beam-former. The Satellite link is stablished over flat un-correlated Nakagami-m/Suzuki fading channels as the second problem. On the other hand, the mentioned optimization problem is robustly solved as the third important problem, while considering inter-cell interferences in the multi-cell scenario. Robust solution is performed due to the partial knowledge of each cell from the others in which the link capacity is maximized. Analytical results are conducted to investigate the merit of system.