CAREER: Pushing the Limits of Low-Power Wide-Area Networks

未来的智慧城市将不得不为数百万能源匮乏的物联网设备提供互联网连接，即使是距离最近的无线基站几英里的设备。为此，近年来部署了新型低功耗广域网（LP-WAN），如LoRa和NB-IoT。不幸的是，今天的LP-WAN技术需要电池为这些设备供电，这影响了它们的维护成本和可靠性。该提案旨在开发一个城市规模的LP-WAN架构，将连接，传感甚至能源卸载到功能更强大的基站和云基础设施。我们开发了一种架构，在这种架构中，基站积极协作，以实现与低功耗设备的更快、更可靠的连接，感知它们的位置和周围环境，并首先提供它们运行所需的能量。拟议的工作有一个详细的综合教育和推广计划，包括课程项目，利用现场试验台和夏季实验室的K-12学生在大匹兹堡。这项工作将首先部署到CMU现有的智能传感器网络中，然后通过与匹兹堡市的广泛合作，扩展到周围的城市基础设施中，形成首个由大学主导的可编程LP-WAN部署。这项工作将沿着三个方向在密集的智能城市部署中实现低功耗广域网：（1）远程无线充电：首先，该提案调查了基站的一个系统，该系统将电力发送到未知位置的无电池客户端。我们探索基站和客户端设计，以在远距离上执行无线充电，数量级高于先前的工作。(2)推动LP-WAN速度和扩展限制：接下来，拟议的工作探索了一种解决方案，即使是在任何单个基站都无法检测到的最弱的LP-WAN信号也可以解码冲突。该提案解释了为什么功率匮乏的LP-WAN客户端甚至需要在客户端实现普通的PHY层功能：无线电配置、解码和速率自适应，以便将这些功能卸载到功能更强大的基础设施。该提案随后探索了基站在回程带宽有限的情况下在云端进行协作的智能方法。(3)城市规模无线传感：最后，拟议的工作研究了新的传感解决方案，该解决方案使用从城市范围内的低功率无线电以及低地球轨道上的立方体卫星接收的RF信号测量，在边缘和云端进行整理。我们评估这样一个系统如何能够在城市范围内感知结构健康和大气湿度等属性，而无需在低功耗设备上安装专用传感器。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审查标准进行评估，被认为值得支持。

Future smart cities will have to provide Internet connectivity to millions of energy-starved Internet-of-Things devices - even those several miles away from the nearest wireless base station. To this end, recentyears have seen novel Low-Power Wide Area Networks (LP-WANs) deployed, such as LoRa and NB-IoT.Unfortunately, today’s LP-WAN technologies require a battery to power these devices, which impactstheir maintenance cost and reliability. This proposal aims to develop a city-scale LP-WAN architecturethat offloads connectivity, sensing and even the source of energy to the more capable base stations andcloud infrastructure. We develop an architecture where base stations actively collaborate to enable fasterand more reliable connectivity to low-power devices, sense their location and surroundings and provideenergy they require to operate in the first place. The proposed work has a detailed integrated education andoutreach program including course projects that leverage a live testbed and summer labs for K-12 studentsin Greater Pittsburgh. The proposed work will be deployed initially to network existing smart sensors atCMU and later scale to surrounding city infrastructure, through extensive collaborations with the City ofPittsburgh, forming a first-of-its-kind university-led programmable LP-WAN deployment.The proposed work enables Low-Power Wide-Area Networking in dense smart-city deployments alongthree axes: (1) Long-Range Wireless Charging: First, the proposal investigates a system at the base stationsthat beams power to battery-free clients at unknown locations. We explore base station and client designs toperform wireless charging over large distances, orders-of-magnitude higher than prior work. (2) PushingLP-WAN Speed and Scaling Limits: Next, the proposed work explores a solution to decode collisions fromeven the weakest of LP-WAN signals that cannot be detected at any single base station. The proposal argueswhy power starved LP-WAN clients motivate the need for even mundane PHY-layer functions at the client:radio configuration, decoding and rate adaptation - to be offloaded to the more capable infrastructure.The proposal then explores intelligent ways for base stations to collaborate at the cloud, despite limitedbackhaul bandwidth. (3) City-Scale Wireless Sensing: Finally, the proposed work investigates novel sensingsolutions that use RF signal measurements received both from city-wide low-power radios as well asCubeSats in Low-Earth Orbit, collated at the edge and cloud. We evaluate how such a system can senseproperties such as structural health and atmospheric moisture at city-scale, without requiring dedicatedsensors on low-power devices.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.