EARS: Directional Spectrum Sensing and Communications Utilizing Beam- and Frequency-Agile Parasitic Antenna Arrays

The University Of Central Florida Board Of Trustees, Orlando FL

Investigators

Abstract

Abstract Title: Directional Spectrum Sensing and Communications Utilizing Beam- and Frequency-Agile Parasitic Antenna Arrays This multidisciplinary research will address some of the major challenges in enabling the next generation of spectrum efficient and energy efficient wireless communication systems for a wide range of applications, including personal communications, emergency-response, and cyber-physical systems (e.g., intelligent transportation systems and the smart-grid), by developing collaboration between two fields of signal processing and communication theory and antenna design.The principal investigators (PIs) will develop a novel beam- and frequency-agile antenna and new signal processing and communication techniques that take full advantage of the antenna capabilities, in order to enable directional spectrum sensing and communications for portable lightweight terminals and provide significant spectral efficiency gains. This research has multifaceted benefits in advancing the field, and in education and diversity (i) It will make a significant impact on the theory and practice of the evolving cognitive radio networks and technologies, for a variety of applications that benefit society. (ii) It will provide a unique opportunity to bond the two research groups supervised by the PIs and enhance research and education through this partnership. The PIs will train graduate and undergraduate students and will actively engage in the stimulation and development of the field. The undergraduate students will gain experience with research in an interesting area. (iii) It will increase the participation of under-represented students in the PIs? research groups. The PIs will use the resources available through the UCF Summer mentoring fellowship program, which provides financial support for the minority students who are interested in conducting research with a faculty mentor. (iv) It will integrate research and education through incorporation of the research results into the Electrical and Computer Engineering graduate curriculum. The research thrusts are: (i) Design of a low-cost beam- and frequency-agile antenna, using an Electrically Steerable Parasitic Array Radiator (ESPAR) approach: These ESPAR antenna arrays require minimum number of phase shifters by parasitically coupling antenna elements. Continuous beam (main lobe and null) as well as frequency scanning can be realized simultaneously within the antenna structure. The ESPAR antenna arrays will be used for both directional spectrum sensing and communications. (ii) Model-based signal processing for directional spectrum sensing utilizing the ESPAR antennas: The PIs will develop a signal model for the ESPAR antennas. Based on this signal model, energy and eigenvalue-based detectors will be developed, which do not require any prior information about the signal of primary users (PUs) to be detected. The energy detector, although simple, requires knowledge of the receiver noise level. On the other hand, the eigenvalue-based detectors do not require this information and hence are insensitive to uncertainties in receiver noise level. Comparing detection performance of eigenvalue-based detectors against that of energy detectors for omnidirectional antennas unveils the improvement in spectrum sensing accuracy provided by the ESPAR antennas. (iii) Directional communications utilizing the ESPAR antennas: For a system where a pair of secondary users (SUs) wishes to communicate in the presence of primary user( PU) activities, and based on the developed signal model, several constrained communication optimization problems will be formulated, which aim to optimize a physical layer performance metric, subject to interference level constraint, in order to find the best steering angles for SU transmitter and receiver. (iv) Testbed: a low-cost yet flexible test platform will be developed to verify the directional spectrum sensing and communication schemes with the ESPAR antennas. This platform is able to adapt to different frequencies, bandwidths, modulation schemes, and antenna structures.