Toward Ubiquitous Connectivity via Unlicensed LPWANs

该研究旨在设计LoRaWAN系统的通用网络引擎LRNet，以提供无处不在的物联网（IoT）连接。具体来说，LRNet有望实现更好的设备共存和更高的链路容量。在第一年，这主要是通过设计新的弹性信号接收算法来实现的。为此，我们建立了一个室内LoRaWAN原型，其中两个USRP N210软件定义无线电作为LoRaWAN网关，12个Dragino LoRa Shields作为LoRaWAN终端设备。在第二年，我们用几个商用LoRaWAN网关和更多数量的LoRaWAN终端设备构建了一个户外LoRaWAN原型。这个原型被部署在一个大学校园环境中。关于弹性信号接收问题，我们发表了一篇论文，提出了一种物理层防碰撞解决方案。我们还进行了一些实验来研究LoRaWAN中的介质访问控制（MAC）层问题。我们发表了两篇论文，分别提供了LoRaWAN MAC的综合教程和新设计的MAC协议，以提高能源公平性。特别值得一提的是，该提议的MAC协议在一次国际会议上获得了最佳论文奖。

This research aims to design LRNet, a one-size-fits-all networking engine for LoRaWAN systems, to provide ubiquitous Internet-of-Things (IoT) connectivity. Specifically, LRNet is expected to enable better device coexistence and higher link capacity. In the first year, this is achieved mainly via the design of novel algorithms for resilient signal reception. To this end, we have built an indoor LoRaWAN prototype with two USRP　N210 software-defined radios as LoRaWAN gateways and twelve Dragino LoRa Shields as LoRaWAN end devices. In the second year, we have built an outdoor LoRaWAN prototype with several commodity LoRaWAN gateways and a larger number of LoRaWAN end devices. This prototype was deployed in a university campus environment. Regarding the issue of resilient signal reception, we have published a paper to present a physical-layer anti-collision solution. We have also conducted several experiments to study the medium access control (MAC)-layer issues in LoRaWAN. We have published two papers to provide a comprehensive tutorial of LoRaWAN MAC and a newly-designed MAC protocol for energy fairness improvement, respectively. Particularly, this proposed MAC protocol received the Best Paper Award at an international conference.