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

能量收集传感器节点之间的高效无线通信可以提高应急服务、农业、智能城市和国防应用的效率和生产力。 实现这种更高水平的传感有可能彻底改变对周围环境的更好理解，并进一步优化家庭和企业的有效运营。 它还将提供对潜在危险情况的早期检测，并为老龄化人口提供更好的生活质量。 随着连接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，降低每个传感器节点的功耗和物理尺寸对于保持网络硬件不显眼和更容易部署非常重要。该项目旨在通过启用具有能量收集传感器节点的资源感知无线通信网络来弥合功率和尺寸差距，其中可用能量可以具有巨大的变化并利用24 GHz的更高频谱。 网络传感器节点的可重新配置的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水平，基于可用功率如何分配，在更大的网络中具有自动适应的角色。 该项目还包括一些教育活动，如K-12学生的STEM研讨会，本科生的研究经验和课程开发。 该项目将为本科生和研究生提供真实的案例，让他们学习如何将实验室的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中几个层次的基本挑战。 这些将从链路和网络考虑因素（例如基于节点或网络级功率可用性调整链路要求）到可重新配置的收发器块（在物理层中实现更高级别的功能）。 这些收发器块包括多模式接收器以及发射器，所述多模式接收器可以动态地在真实的时间内为数据速率或灵敏度折衷功率，所述发射器甚至在显著的回退功率电平下也是高效的。 此外，该项目将把超低功耗无线操作推向K波段的更高频率（例如，24 GHz），这解决了较低频率下频谱有限的问题，同时还允许在相同效率的情况下大幅减小天线尺寸。该项目还将推进无线电电子和电磁学之间的协同设计，包括阻抗匹配网络和为低功率、高频、高阻抗条件设计的天线。 在这个项目中开发的基础研究和基本的设计原则将证明与概念验证无线传感器节点。 该项目还将推进在对称无线传感器节点的网状网络中实现动态非对称链路和角色选择，以根据可用功率优化网络功能。 该研究具有重要影响，因为它将传统的孤立设计空间结合在一起，并利用RF、超低功耗电路和天线设计中的基础研究来解决未来无线传感器网络部署中的关键瓶颈。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响评审标准进行评估，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.