Directional Link Management using In-Band Full-Duplex Free Space Optical Transceivers for Aerial Nodes

Free-space optical (FSO) communication has become very popular for wireless applications to complement and, in some cases, replace legacy radio-frequency for advantages like unlicensed band, spatial reuse, and enhanced security. Even though FSO can achieve very high bit-rate (tens of Gbps), range limitation due to high attenuation and weather dependency has always restricted its practical implementation to indoor application like data centers and outdoor application like Project Loon. Building-to-building communication, smart cars, and airborne drones are potential futuristic wireless communication sectors for mobile ad-hoc FSO networking. Increasing social media usage demands high-speed mobile connectivity for applications like video call and live video stream on the go. For these scenarios, implementation of in-band full-duplex FSO (IBFD-FSO) transceivers will potentially double the network capacity to improve performance and reliability of the communication link. In this work, we focus on implementing prototypes of FSO transceivers on mobile platform using both off-the-shelf and customized components. Current goal is to implement a prototype of IBFD-FSO transceiver using VCSEL as transmitter and PIN photodiode as receiver at 900 nm wavelength. We are considering atmospheric attenuation, FSO beam propagation model, geometry, and tiling of the components to optimize the link performance while keeping the package low-cost and mobile, ensuring connectivity to mass population. Eventually, our goal is to have communication between multiple airborne drones through IBFD-FSO transceivers by discovering each other and maintaining established link. Applications of this research is not only limited to the conceived idea of smart cities, but it can also have real impact on disaster management in times of wildfire or hurricane