Researh
Optical Wireless Communication for Virtual Reality Systems
In this work, we present a novel multi-detector hemispherical VR headset design to tackle the beam misalignment problem caused by the VR user's random head orientation. We provide detailed analysis on how the number of detectors on the headset can be minimized while maintaining the required beam alignment and providing high quality VR experience.
Free-Space-Optical Link Maintenance Between Autonomous Mobiles
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). 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.
Line-of-Sight Discovery Between UAVs Using Highly Directional Transceivers
In an ad hoc network with multiple stationary or mobile nodes, the first and foremost task is neighbor discovery for establishing communication links. Nodes equipped with highly directional mmwave antennas or FSO transceivers require line-of-sight (LOS) discovery for establishing such communication links. In RF challenged conditions or in environments where sharing GPS information may not be safe (e.g., in war zones), such highly directional communication systems can be very useful. In this work, we devised and algorithm for neighbor discovery that can use hybrid systems utilizing omni-directional RF – directional FSO/mmwave communication. We proposed an LOS discovery algorithm that can be applied to 3D mobile wireless ad hoc networks. We have developed a proof-of-concept prototype using DJI Matrice 100 drones and experimentally evaluated the devised LOS discovery method.
In-Band LOS Discovery Between Drones
In this work, we propose a novel method for LOS discovery between two nodes (e.g., hovering UAVs/drones/quadcopters) in a 3D environment. We consider each node to be equipped with a highly directional FSO/RF transceiver, mounted on a mechanically steerable spherical structure/head. Thus, the transceiver can be steered to scan 360o along the horizontal plane and 360o along the vertical plane. We also assume that there is no GPS available to acquire location information. Moreover, we assume that there is no additional omnidirectional RF channel available to share location or any other information. The only way for the nodes to discover each other is to use the mechanically steerable highly directional transceivers to scan the surrounding 3D space in search of the neighbor node. Thus, in-band operation is the only viable option we consider while comparing to the cases with more information exchange capability between the nodes.
Line-of-Sight Discovery Using Highly Directional FSO/RF Transceivers in 2D Ad Hoc Networks
In this work, we focus on neighbor discovery using full duplex directional transceivers. We consider two nodes that can discover each other by steering their transceivers with a randomly chosen angular speed and performing a simple three way handshaking protocol.We provide a theoretical analysis of the proposed neighbor discovery method. Additionally, we propose an algorithm where each node chooses its transceiver’s angular speed and renews it if the neighbor is not discovered within an optimal time interval. We evaluate the algorithm via simulations and show its effectiveness under various scenarios.
In-Band Full-Duplex Free-Space-Optical Transceiver Development
We present a proof-of-concept prototype for an IBFD-FSO transceiver built using off-the-shelf components, implementing passive isolation technique to prevent the receiver from self-interference. We conducted experiments using the transceiver to show the effectiveness in isolating self-signal in real test-bed, demonstrating IBFD optical wireless communication channel by successfully eliminating self-interference and optical feedback.