This integrative systems proposal focuses on the development of a diffuse optical local area network (LAN) making use of Multiple-Input, Multiple-Output (MIMO) techniques. MIMO theory, utilizing arrays at both the transmitter and the receiver, was originally conceived and largely developed in the realm of radio frequency communications to increase spectral capacity and link robustness. Traditional optical systems have been point-to-point, utilizing a direct line-of-sight connection. However, when the signal is blocked or the system is misaligned, the data rate is severely limited. Diffuse optical networks overcome the blockage and alignment issues of line-of-sight communication links at the cost of reduced received optical power and lower data rate. The intellectual merit of this project involves applying MIMO techniques, including advanced space-time coding algorithms, in a diffuse optical wireless network testbed to overcome optical power limitations and increase the data rate of the system. The transceiver modules and the diffuse optical MIMO network consisting of infrared sources, detectors, filters, and lenses will be designed and constructed. Furthermore, a hybrid system in a modular, software defined radio framework, making coordinated use of both diffuse optical and radio frequency transceivers to demonstrate increased energy efficiency, robustness, and security in indoor LAN applications will also be constructed. The concept of "modality diversity" for improving the next generation communication networks will be demonstrated using the proposed hybrid systems. Broader Impacts: This work will obtain broader impacts beyond the stated research goals, as we will foster an interest in science and engineering among high school students, as well as develop a graduate cross-medium networking course.
