A Tb/s Indoor MIMO Optical Wireless Backhaul System Using VCSEL Arrays

TL;DR

This paper presents a systematic design and analysis of a Tb/s indoor MIMO optical wireless backhaul system using VCSEL arrays, addressing alignment challenges and optimizing performance for 6G networks.

Contribution

It introduces a unified misalignment model for MIMO VCSEL-based OWC links and analyzes system performance considering various practical factors.

Findings

Achieves over 1 Tb/s data rate in simulation.

Provides guidelines for system design considering misalignment.

Models misalignment errors comprehensively for MIMO OWC systems.

Abstract

In this paper, the design of a multiple-input multiple-output (MIMO) optical wireless communication (OWC) link based on vertical cavity surface emitting laser (VCSEL) arrays is systematically carried out with the aim to support data rates in excess of 1 Tb/s for the backhaul of sixth generation (6G) indoor wireless networks. The proposed design combines direct current optical orthogonal frequency division multiplexing (DCO-OFDM) and a spatial multiplexing MIMO architecture. For such an ultra-high-speed line-of-sight (LOS) OWC link with low divergence laser beams, maintaining alignment is of high importance. In this paper, two types of misalignment error between the transmitter and receiver are distinguished, namely, radial displacement error and orientation angle error, and they are thoroughly modeled in a unified analytical framework assuming Gaussian laser beams, resulting in a generalized misalignment model (GMM). The derived GMM is then extended to MIMO arrays and the performance of the MIMO-OFDM OWC system is analyzed in terms of the aggregate data rate. Novel insights are provided into the system performance based on computer simulations by studying various influential factors such as beam waist, array configuration and different misalignment errors, which can be used as guidelines for designing short range Tb/s MIMO OWC systems.