Wireless networks have been widely deployed for many Internet-of-Things (IoT) applications, like smart cities and precision agriculture. Low Power Wide Area Networking (LPWAN) is an emerging IoT networking paradigm to meet three key requirements of IoT applications, i.e., low cost, large scale deployment and high energy efficiency. Among all available LPWAN technologies, LoRa networking has attracted much attention from both academia and industry, since it specifies an open standard and allows us to build autonomous LPWAN networks without any third-party infrastructure. Many LoRa networks have been developed recently, e.g., managing solar plants in Carson City, Nevada, USA and power monitoring in Lyon and Grenoble, France. However, there are still many research challenges to develop practical LoRa networks, e.g., link coordination, resource allocation, reliable transmissions and security. This article provides a comprehensive survey on LoRa networks, including the technical challenges of deploying LoRa networks and recent solutions. Based on our detailed analysis of current solutions, some open issues of LoRa networking are discussed. The goal of this survey paper is to inspire more works on improving the performance of LoRa networks and enabling more practical deployments.

中文翻译：

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LoRa 网络调查：研究问题、当前解决方案和未解决的问题

无线网络已广泛部署在许多物联网 (IoT) 应用中，例如智慧城市和精准农业。低功耗广域网（LPWAN）是一种新兴的物联网网络范式，可满足物联网应用的三个关键要求，即低成本、大规模部署和高能效。在所有可用的 LPWAN 技术中，LoRa 网络引起了学术界和工业界的广泛关注，因为它指定了一个开放标准，允许我们在没有任何第三方基础设施的情况下构建自主的 LPWAN 网络。最近开发了许多 LoRa 网络，例如管理美国内华达州卡森市的太阳能发电厂以及法国里昂和格勒诺布尔的电力监控。然而，开发实用的 LoRa 网络仍然存在许多研究挑战，例如链路协调、资源分配、可靠传输和安全。本文提供了对 LoRa 网络的全面调查，包括部署 LoRa 网络的技术挑战和最近的解决方案。基于我们对当前解决方案的详细分析，讨论了 LoRa 网络的一些未解决的问题。本调查论文的目标是激发更多关于提高 LoRa 网络性能和实现更实际部署的工作。