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

摘要标题：利用波束和频率捷变寄生天线阵列的定向频谱感测和通信这项多学科研究将解决使下一代频谱高效和节能无线通信系统能够用于广泛应用的一些主要挑战，包括个人通信，紧急响应和网络物理系统（例如，智能交通系统和智能电网），通过发展信号处理和通信理论与天线设计两个领域之间的合作。主要研究人员（PI）将开发一种新型波束和频率捷变天线，以及充分利用天线功能的新信号处理和通信技术，以便实现便携式轻型终端的定向频谱感测和通信，并提供显著的频谱效率增益。这项研究在推进该领域，教育和多样性方面具有多方面的好处（i）它将对不断发展的认知无线电网络和技术的理论和实践产生重大影响，用于各种有益于社会的应用。(ii)它将提供一个独特的机会，将两个由PI监督的研究小组联系在一起，并通过这种伙伴关系加强研究和教育。PI将培训研究生和本科生，并将积极参与该领域的刺激和发展。本科生将在一个有趣的领域获得研究经验。(iii)它将增加代表性不足的学生在PI的参与？研究团体。PI将使用通过UCF夏季辅导奖学金计划提供的资源，该计划为有兴趣与教师导师进行研究的少数民族学生提供财政支持。(iv)它将通过将研究成果纳入电气和计算机工程研究生课程来整合研究和教育。研究重点是：（i）使用电可控寄生阵列辐射器（ESPAR）方法设计低成本波束和频率捷变天线：这些ESPAR天线阵列通过寄生耦合天线元件而需要最少数量的移相器。在天线结构内可以同时实现连续波束（主瓣和零点）以及频率扫描。ESPAR天线阵列将用于定向频谱传感和通信。(ii)利用ESPAR天线进行定向频谱感知的基于模型的信号处理：PI将为ESPAR天线开发信号模型。基于该信号模型，将开发基于能量和特征值的检测器，其不需要关于待检测的主用户（PU）的信号的任何先验信息。 能量检测器虽然简单，但需要接收机噪声电平的知识。另一方面，基于特征值的检测器不需要这些信息，因此对接收机噪声水平的不确定性不敏感。将基于特征值的检测器的检测性能与全向天线的能量检测器的检测性能进行比较，揭示了ESPAR天线提供的频谱感测精度的改进。 (iii)利用ESPAR天线的定向通信：对于其中一对次级用户（SU）希望在存在主用户（PU）活动的情况下进行通信的系统，并且基于所开发的信号模型，将用公式表示几个受约束的通信优化问题，其旨在优化物理层性能度量，受到干扰水平约束，以便找到SU发射机和接收机的最佳转向角。(iv)试验台：将开发一个低成本但灵活的测试平台，以验证ESPAR天线的定向频谱感测和通信方案。该平台能够适应不同的频率、带宽、调制方案和天线结构。

Abstract Title: Directional Spectrum Sensing and Communications Utilizing Beam- and Frequency-Agile Parasitic Antenna ArraysThis 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.