Problem Statement and Motivation

FSO is a major candidate to complement traditional radio frequency or RF networks and can help solve the capacity crunch faced by RF wireless technologies. It uses the unlicensed optical spectrum and can easily reach very high modulation speeds (tens of Gbps). Compared to RF, it can provide much higher bandwidth to transfer large volumes of data. The high directionality of FSO communication systems provides high spatial reuse and larger network capacity. FSO can also provide connectivity in unfavorable conditions, e.g., presence of RF jamming or interception. Despite the advantages over RF communication, the major challenge faced by FSOC is its vulnerability against mobility. Mobile FSOC requires effective maintenance of LOS. In the first part of this project, we proposed a novel scheme showing the feasibility of maintaining FSO links between two mobile robot cars with minimal disruption using mechanically steered transceivers and a simple auto-alignment mechanism. We also presented a prototype implementation of such mobile FSO nodes. We demonstrated that using such mechanical steering capability to control the rotation of the transceivers, the problem of LOS maintenance can be dealt with effectively without global positioning system (GPS).

 Equipping Unmanned-Aerial-Vehicles (UAVs) with high-speed FSO transceivers can enable a large set of applications involving transfers of very large wireless data. UAVs with several sensors generate a lot of data which may require to be delivered to either another UAV or a ground station. The higher data rate required for communication links to transmit more information between UAVs triggered the idea of employing FSO transceivers to meet the increasing demand. UAV-based FSO communication is a challenging but emerging technology. So, in the second part of this project, we focused on establishing communication links among UAVs or drones equipped with FSO transceivers in a 3D wireless ad hoc network. We proposed schemes for FSO link maintenance between flying drones/UAVs equipped with laser and LED transmitters.