Simulation Analysis of Mobility Effects on Indoor Free-Space-Optical- Networks

In this paper we introduce simulation of optical multi-element antennas that enable mobility and high bandwidth in Free Space Optical (FSO) networks. The challenge of FSO is to build systems that can tackle line of sight (LOS) alignment and maintenance issues. By addressing these critical aspects of LOS alignment in such networks, we demonstrate the potential for mobility by simulation. We can achieve mobility by use of 3-d spherical optical antennas tessellated with optical transceiver pairs. This distribution of transceivers creates omni directional line of site which we take advantage of to create connectivity even for mobile nodes with FSO antennas. In particular, we first evaluate a basic 2d scenario where we have a single mobile FSO node around stationary FSO nodes while maintaining connectivity. Then we examine a more sophisticated and realistic indoor scenario involving a pair of 3-d spherical antennas where one antenna is fixed and the other moves about it randomly. To our knowledge, this is the first attempt to use angular and spatial diversity implemented as a multi-element optical antenna to achieve mobility in such a network. Broader impact of our work is to make FSO communication technology widely applicable in mobile, ad-hoc, and multi-hop wireless networks.