A VCSEL Array Transmission System with Novel Beam Activation Mechanisms

TL;DR

This paper introduces a novel VCSEL array system for indoor optical wireless communication, featuring two beam activation methods—CCR-based low-latency activation and ODTx for uplink and robustness—analyzing their performance through system-level simulations.

Contribution

The study proposes two innovative beam activation mechanisms for VCSEL arrays in indoor OWC, enhancing real-time responsiveness and robustness to user orientation, with comprehensive system performance analysis.

Findings

CCR-based activation offers very low latency.

ODTx method provides robustness to user orientation.

FWHM angle of 4° yields optimal performance.

Abstract

Optical wireless communication (OWC) is considered to be a promising technology which will alleviate traffic burden caused by the increasing number of mobile devices. In this study, a novel vertical-cavity surface-emitting laser (VCSEL) array is proposed for indoor OWC systems. To activate the best beam for a mobile user, two beam activation methods are proposed for the system. The method based on a corner-cube retroreflector (CCR) provides very low latency and allows real-time activation for high-speed users. The other method uses the omnidirectional transmitter (ODTx). The ODTx can serve the purpose of uplink transmission and beam activation simultaneously. Moreover, systems with ODTx are very robust to the random orientation of a user equipment (UE). System level analyses are carried out for the proposed VCSEL array system. For a single user scenario, the probability density function (PDF) of the signal-to-noise ratio (SNR) for the central beam of the VCSEL array system can be approximated as a uniform distribution. In addition, the average data rate of the central beam and its upper bound are given analytically and verified by Monte-Carlo simulations. For a multi-user scenario, an analytical upper bound for the average data rate is given. The effects of the cell size and the full width at half maximum (FWHM) angle on the system performance are studied. The results show that the system with a FWHM angle of $4^\circ$ outperforms the others.