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

未来的智能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--即使是那些距离最近的无线基站几英里远的设备。为此，近年来已经部署了新的低功耗广域网，如LORA和NB-IoT。遗憾的是，今天的广域网技术需要电池来为这些设备供电，这影响了这些设备的维护成本和可靠性。这项提议旨在开发一个城市规模的LP-广域网架构，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，其中基站积极协作，以实现与低功耗设备更快、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，包括利用现场试验台和大匹兹堡K-12学生暑期实验室的课程项目。这项拟议的工作首先将部署在CMU现有的智能传感器上，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，形成首个由大学主导的可编程LP-广域网络部署。拟议的工作将使密集的智能城市部署中的低功耗广域网络沿着三个轴：(1)远程无线充电：首先，该提案调查基站的一个系统，该系统向未知位置的无电池客户端传输电力。我们探索了基站和客户端的设计，以实现远距离无线充电，比以前的工作高出一个数量级。(2)推进LP-广域网的速度和扩展限制：接下来，提出了一种解决方案，以解码来自最弱的LP-广域网信号的冲突，这些冲突在任何单个基站都无法检测到。该提案论证了为什么电力匮乏的LP-广域网客户端需要在客户端实现平凡的物理层功能：无线电配置、解码和速率适配--将其卸载到功能更强大的基础设施。然后，该提案探索了基站在云中协作的智能方法，尽管回程带宽有限。(3)城市规模的无线传感：最后，拟议的工作调查了新颖的传感解决方案，这些解决方案使用从城市范围的低功率无线电以及低地球轨道上的立方体卫星接收的射频信号测量，在边缘和云中进行整理。我们评估了这样的系统如何能够感知城市规模的结构健康和大气湿度等属性，而不需要在低功率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。

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.