CAREER: Resource Aware Adaptability of Wireless Sensor Network Links in Variable Energy Environments

能源采集传感器节点之间的高效无线通信可以在应急服务、农业、智能城市和国防应用中实现更高的效率和生产力，仅举几例。实现这种更高水平的传感有可能使人们更好地了解周围环境，并有能力进一步优化家庭和企业的高效运营。它还将及早发现潜在危险情况，并为老龄化人口提供更好的生活质量。随着互联设备的数量和密度的增加，广泛使用的5 GHz及以下频段的电磁频谱变得越来越拥挤和拥挤。同时，减少每个传感器节点的功耗和物理尺寸对于保持网络硬件的隐蔽性和更容易部署非常重要。该项目寻求通过启用资源感知无线通信网络和能量采集传感器节点来弥合功率和尺寸差距，在这些节点上，可用能量可以有巨大的变化，并在24 GHz处利用更高的频谱。网络传感器节点的可重配置收发器将能够在可用功率稀缺时维持关键服务，同时在功率充足时利用更高的功率级别，并根据可用功率的分配方式在更大的网络中自动调整角色。该项目还包括一些教育活动，如为K-12学生举办的STEM讲习班，为本科生提供的研究经验，以及课程开发。与当地创业公司的创业研讨会和实地访问系列将为本科生和研究生提供真实的例子，学习如何将实验室想法转化为现实世界的应用，同时造福当地社区。该项目将调查无线传感器网络硬件层次结构中的几个层面的基本挑战。这些考虑范围从链路和网络考虑因素，例如根据节点或网络级别的功率可用性调整链路要求，一直到在物理层实现更高级别功能的可重新配置的收发器模块。这些收发模块包括可实时动态权衡功率以换取数据速率或灵敏度的多模式接收器，以及即使在显著的退避功率水平下也非常高效的发射机。此外，该项目将把超低功率无线操作推向K频段(例如，24 GHz)的较高频率，这将缓解较低频率的频谱有限的问题，同时还允许在相同效率的情况下大幅减小天线尺寸。该项目还将促进无线电电子学和电磁学之间的合作设计，包括阻抗匹配网络和天线，这些天线是为低功率、高频、高阻抗条件而设计的。本项目中开发的基础研究和基本设计原则将通过概念验证无线传感器节点进行演示。该项目还将在对称无线传感器节点的网状网络中推进动态非对称链路和角色选择的实现，以基于可用功率优化网络功能。这项研究具有重要影响，因为它将汇集传统上孤立的设计空间，并利用射频、超低功率电路和天线设计领域的基础研究，以解决未来无线传感器网络部署的关键瓶颈。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Efficient wireless communication between energy harvesting sensor nodes can enable greater efficiency and productivity in emergency services, agriculture, smart cities, and defense applications, to name a few. Enabling this heightened level of sensing has the potential to revolutionize greater understanding of the surrounding environment and the ability to further optimize efficient operation of homes and businesses. It will also provide early detection of potentially hazardous situations and enable better quality of life for an aging population. As the number and density of connected devices have increased, electromagnetic spectrum at widely used frequency bands of 5 GHz and below has become increasingly crowded and congested. At the same time, reducing the power consumption and physical size of each individual sensor node is important to keep the network hardware unobtrusive and more easily deployable. This project seeks to bridge the power and size gap by enabling resource-aware wireless communication network with energy harvesting sensor nodes where available energy can have immense variation and utilize higher frequency spectrum at 24 GHz. The reconfigurable transceivers of network sensor nodes will be capable of maintaining critical services when available power is scarce while taking advantage of higher power levels when power is abundant, with automatically adaptable roles within the greater network based upon how that available power is distributed. This project also includes several educational activities such as STEM workshops for K-12 students, research experiences for undergraduates, and course development. An entrepreneurial seminar and site visit series with local startup companies will provide real examples for undergraduate and graduate students to learn how to transform laboratory ideas to real-world applications while benefiting their local communities.The project will investigate fundamental challenges at several layers in the hardware hierarchy of wireless sensor network. These will range from link and network considerations, such as adapting the link requirements based on node- or network-level power availability, down to reconfigurable transceiver blocks that enable higher level functionality in physical layer. These transceiver blocks include multi-mode receivers that can dynamically trade off power for data rate or sensitivity in real time as well as transmitters that are highly efficient even at significant back-off power levels. Additionally, the project will push ultra-low power wireless operation to higher frequencies in K-band (e.g., 24 GHz), which alleviates the issue of limited spectrum at lower frequencies, while also allowing for drastically reduced antenna size with the same efficiency. The project will also advance the co-design between the radio electronics and the electromagnetics including impedance matching networks and antennas engineered for low-power, high-frequency, high-impedance conditions. The fundamental studies and underlying design principles developed in this project will be demonstrated with proof-of-concept wireless sensor nodes. This project will also advance the implementation of dynamically asymmetric links and role selection in a mesh network of symmetric wireless sensor nodes to optimize the network functionality based on available power. The research has important impacts because it will bring together traditionally siloed design spaces, and leverage fundamental research within RF, ultra-low power circuits, and antenna design to address critical bottlenecks in deployment of future wireless sensor networks.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.