Final Report : Performance Limits of Non - Line - of - Sight Optical Communications Report

Number of Papers published in peer-reviewed journals: Final Report: Performance Limits of Non-Line-of-Sight Optical Communications Report Title Solar blind ultraviolet (UV) communication technology holds the promise of superior non-line-of-sight (NLOS) link connectivity through atmospheric scattering, and significantly relaxed tracking and pointing requirements. During the last Project, the research group at the University of California, Riverside, recently demonstrated these attributes, based on deep UV light emitting diodes (LEDs), solar blind filters, and high efficiency solar blind photo detectors. In this project, we address the main challenges towards optimizing the UV communication system performance. It covers channel modeling, channel capacity, advanced communication and network techniques, high sensitive transceiver design and different system tradeoffs. First, both integrated analytical and Monte Carlo UV channel models are developed to simulate the channel impulse response and pass loss. Second, UV LEDs based and UV laser based channel test platforms are built to experimentally study UV channel characteristics and validate the models. Aware of the huge pass loss property of a UV signal, it is hard to synchronize the UV signal frame. We integrate Universal Software Radio Peripheral (USRP) into UV communication system and employ GPS as synchronized signal to get better communication performance. Based on NLOS communication link geometry and UV signal interaction with the atmosphere, we develop two analytical channel models that describe the path loss in an integral form and closedform respectively. Utilizing curve-fitting with field measurements, an easy-to-use empirical model is further developed. The results are then applied to study performance of a NLOS UV network, from outage probability to transmission throughput and network connectivity in a multi-user interference environment. For the UV network, we develop a novel contention-based MAC protocol (UVOC-MAC) that inherently accounts for the UV PHY layer and fully exploits multi-fold spatial reuse opportunities. We further develop an efficient neighbor discovery protocols by accounting for the varying channel qualities along different scattering directions. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: (b) Papers published in non-peer-reviewed journals (N/A for none) 10.00