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

射频频谱是一种宝贵的资源，如果有效利用，可以促进经济增长，提高我们的生活质量，并加强公共安全。然而，由于对无线服务的需求不断增长，RF频谱变得过于拥挤。虽然频谱似乎被各种无线系统完全占用，但仍有许多频率未被积极使用，可以动态分配给其他用户。然而，即使对于最先进的电子设备来说，这也是一个挑战，因为搜索未使用的频率需要大量的计算资源和复杂的硬件。该提案旨在通过利用光子学来克服这一挑战，光子学是一种替代信号处理方法，其带宽和速度比电子学中的对应方法更快。利用所提出的光子技术，射频信号首先被转换为光信号，然后可以几乎瞬时地处理光信号。本计画的研究工作将致力于频谱资源的快速发现与有效利用。该项目还提出了一个与研究工作密切相关的综合教育计划。它包括开发用于学习光纤的移动的应用程序，为当地社区组织光纤研讨会，开发本科新生研讨会和跨学科课程，以及为高中和本科生，特别是那些代表性不足的群体提供研究经验。频谱利用率的提高将使社会上许多重要的无线服务受益，包括移动的通信、远程医疗、远程学习和移动的计算。为了适应无线设备日益增长的使用，需要一种更有效的方法来搜索、发现、使用和共享无线电频谱。这项研究的重点是从根本上改变如何通过光子学技术快速发现和有效利用频谱资源。提出了两个密切相关的研究主题：（i）基于可调谐/可重构的多频带RF滤波器开发实时“扫描和查找”RF频谱扫描系统，以及（ii）基于光子学启用的频率重用在同时发送和接收信号以及生物启发的自动干扰避免的基础上提高频谱使用效率。RF频谱扫描系统利用了独特设计的RF多频带滤波器的超快光学调谐和切换能力以及现有光学器件的瞬时响应。通过超宽带自干扰消除系统实现信号的同时发送和接收。此外，一种新的自动干扰避免技术将被探索。它的灵感来自于生物学中的一个类比--干扰Eigenmannia的回避反应，Eigenmannia是一种电鱼。该提案提出了一种全面的、跨学科的创新方法，以解决频谱稀缺问题，同时提高无线通信中的频谱使用效率。拟议的研究涉及系统设计和实验验证的紧密结合，因此将产生实验室原型，以证明更有效地使用无线电频谱。

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.