Free Space Optical CommunicationDr. Pala with his collaborators Dr. Guvenc (FIU ) and Dr. Yuksel (UNR) received NSF award to study new technologies for both illumination and communication.

Recent proliferation of wireless technologies and choices available to user applications have triggered a tremendous wireless demand, and the wireless nodes are expected to dominate the Internet soon. As the RF spectrum is getting scarcer, we urgently need innovations that will enable leveraging of new wireless spectrum bands and substrates in order to respond to the exploding mobile wireless traffic demand. To complement the scarce RF spectrum, free-space-optical (FSO) (a.k.a. optical wireless) communication has spurred sizable interest as a candidate for high-speed wireless medium. Recent research, including ours, explored the potential for FSO communication in the context of very high-speed mobile ad-hoc and opportunistic networking by offering solutions to its brittleness on mobility and line-of-sight alignment.

Established on the same optoelectronics technology, solid-state lighting (SSL) (a.k.a. smart lighting) technologies are provably superior to the existing lighting technologies due to their durability and efficiency. SSL devices with multiple light emitting diodes (LEDs) are being heavily deployed and commercialized. It is expected that multi-element SSL devices will soon outnumber the traditional lighting technologies. The energy gains and long-term cost-efficiency possible with smart lighting devices are very attractive and urge further optimizations increase their potential gains. These devices have an additional advantage of fast turn-on and turn-off properties that could be leveraged for FSO communication.

diagramThough stemming from the same core technology, the SSL and FSO communication have inherent tradeoffs amongst each other. The lighting efficiency (e.g., illuminated area) is better when the divergence angle of the optoelectronic transmitter is high; whereas the communication efficiency (e.g., transmission range) is better when it is small. If such joint design challenges are tackled and tradeoffs are balanced well at the intersection of the two areas, there is a high-reward opportunity for expanding the scarce wireless spectrum to the large visible bands and a unique set of possible applications. We propose to investigate and develop multi-element “illuminication” structures that perform joint and adaptive optimization of these two conflicting goals: illumination and communication.


Intellectual Merit: Significance of the proposed research lies in the holistic approach to develop a framework to design, optimize and test of illumination-communication systems considering needs and requirements for both functionalities. Our holistic approach is particularly important since we aim to explore multi-input multi-output (MIMO) communication with mobility. Such a joint-design approach with enhanced mobility capability is unique to this proposal. Novelties of the proposed research include (i) joint design of illuminication modules with multi-elements (for redundancy) and spherical alignment (for spatial reuse and uniform illumination) considering both illumination and communication needs and constraints, (ii) adaptive intensity control for energy saving and chromacity control over red-green-blue (RGB) LEDs, (iii) transceiver design with varying field-of-view (FOV) and/or divergence angle, (iv) automatic realignment protocols (via electronic steering and focusing) for mobility, (v) cognitive algorithms for transceiver selection – similar to channel selection in cognitive radio, and (vi) optical wireless localization.

Broader Impact: The proposed inter-disciplinary research will investigate a truly transformational framework for joint-design, optimization and realization of equipment and protocols for advanced illumination and communication capabilities. The protocols and modules have the potential of widely implemented and deployed in wide range of settings including but not limited to residential and commercial buildings, airplanes, military and other high security environments. The protocols could be included future communication standards developed by IEEE and other governing bodies. The modules could be adopted by architects, designers, civil and electrical engineers in the building industry for the future “carbon neutral” or “net-zero” buildings. The grad and undergrad students who will be involved in this project will be the first step for building the workforce in this critical cross-disciplinary field. UNR is located at an EPSCoR state and FIU is one of the largest Hispanic Minority Serving Institutions in the nation. Hence, this project will enable underrepresented Hispanic students to engage in FSO communication and SSL research via a world-class infrastructure. The project will strengthen both UNR’s and FIU’s faculty in research and teaching via established research collaborations as well as the shared software repository to be created. The project will further broaden the institutions’ mission of education, recruitment, retention and mentoring by engaging more minority students in research, by reaching out to local schools, media, and the Internet, and by engaging the students with industrial collaborators.