CAREER:Optically-enabled Scanning and Utilization of Radio Spectrum Opportunities (OSCARS)

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Radio frequency (RF) spectrum is a valuable resource that, if effectively utilized, can boost economic growth, improve our quality of life, and enhance public safety. However, due to growing demand on wireless services, the RF spectrum is becoming overcrowded. Although the spectrum seems to be fully occupied by all kinds of wireless systems, there are many frequencies not actively used and can be dynamically allocated for other users. However, this is challenging even for state-of-the-art electronics, as the search for unused frequencies requires vast amount of computational resources and sophisticated hardware. This proposal aims to overcome this challenge by making use of photonics--an alternative signal processing method that has wider bandwidth and faster speed than its counterpart in electronics. With the proposed photonics techniques, the radio frequency signal is first converted to an optical signal, which can then be processed almost instantaneously. The research effort of this project will be devoted to the fast discovery and efficient use of spectrum resources. This project also proposes a comprehensive education plan closely related to the research effort. It includes developing mobile apps for learning fiber optics, organizing a fiber optics workshop for the local community, developing undergraduate freshman seminar and cross-disciplinary courses, as well as providing research experiences for high school and undergraduate students, especially those from underrepresented groups. The improvement in spectrum usage will benefit many vital wireless services for the society, including mobile communications, remote healthcare, distant learning, and mobile computing. To accommodate the increasing usage of wireless devices, a more effective way to search, find, use, and share the radio frequency spectrum is necessary. The focus of this research is to fundamentally change how spectrum resources can be quickly discovered and used effectively through photonics techniques. Two closely related research themes are proposed: (i) developing a real-time "Scan-and-Find" RF spectrum scanning system based on a tunable/reconfigurable multiband RF filter, and (ii) improving spectrum usage efficiency based on photonics-enabled frequency reuse in simultaneous transmission and reception of signals as well as bio-inspired automatic interference avoidance. The RF spectrum scanning system exploits the ultrafast optical tuning and switching capability of a uniquely designed RF multiband filter as well as the instantaneous response of existing optical devices. The simultaneous transmission and reception of signals is enabled by an ultra-wideband self-interference cancellation system. Furthermore, a novel automatic interference avoidance technique will be explored. It is inspired by an analogy in biology--jamming avoidance response in Eigenmannia, a genus of electric fish. This proposal presents a comprehensive, interdisciplinary, and innovative approach to solve the spectrum scarcity problem while improving spectrum usage efficiency in wireless communications. The proposed research involves a close coupling of system design and experimental validation, and thus will yield laboratory prototypes to demonstrate more effective usage of the radio spectrum.