A Universal Platform for Ubiquitous Wireless Communications Using Radio Over FSO System

In this paper, we present the design concept and performance evaluation results of a newly developed DWDM Radio over Free-Space Optics (RoFSO) system capable of transmitting multiple wireless service signals simultaneously. The system performance is evaluated over 1-km free-space transmission under effects of atmospheric turbulence and attenuation. Effectiveness of a proposed tracking scheme used to mitigate beam angle-of-arrival (AOA) effect and the viability of the communication system using a specially designed optical antenna are illustrated. The properties of free-space propagation under influences of atmospheric turbulence and attenuation are characterized. We then present the performance of wireless signals after being transmitted over the system. We verify that the system can provide a stable connection for wireless services especially with the absence of strong atmospheric turbulence and heavy rain. Finally, we present a consideration on the system application by indicating the possible applicable link range based on the system designed power margin and the tracking system efficiency. The proposed system is expected to be an alternative or be combined with wireless over fiber (WoF) to realize a universal platform for ubiquitous and high throughput wireless communications.

I. Introduction

Recently, communication demand has been increasing with higher requirement on the manner of accessing information at any-time, from anywhere and in any situation. Increasingly the services offered are becoming an indispensable part of daily life. A ubiquitous network, therefore, is necessary to satisfy the demand regardless of geographical locations [1]. In such communication network, heterogeneous devices have to be connected to form a universal network. However, in current wireless networks, operators set up and manage their own radio resources and networks separately. This results in high costs and prevents quick deployment of new wireless services, especially in the areas which lack broadband infrastructure like in-building, underground and rural areas [2].