Is LoRaWAN Really Wide? Fine-grained LoRa Link-level Measurement in An Urban Environment
Is LoRaWAN Really Wide? Fine-grained LoRa Link-level Measurement in An Urban Environment
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DOI：
10.1109/icnp55882.2022.9940375
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发表时间：
2022-10
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影响因子：
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通讯作者：
Yidong Ren;Li Liu;Chenning Li;Zhichao Cao;Shigang Chen
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作者：
Yidong Ren;Li Liu;Chenning Li;Zhichao Cao;Shigang Chen
物联网（IoT）的目标是在不久的将来连接数十亿个低速率和能源受限的终端设备。尽管许多物联网系统已经商业化，但其中大多数都专注于家庭和身体规模的应用。为了在城市规模上建立低成本的物联网，LoRa广域网（LoRaWAN）近年来因其理想的千米甚至更长的通信距离而变得具有吸引力。然而，由于密集部署终端节点的昂贵成本，对LoRa链路行为的理解仍然是粗粒度的，难以完全实现城市环境中LoRaWAN的链路动态，网络覆盖和定位精度。本文展示了通过移动的端节点进行的细粒度LoRa链路级测量。我们部署了两个网关和六个移动的终端节点，并在四个月内在一个6\times 6\ km^{2}$的城市地区收集数据包。评估主要集中在回答三个问题：1）LoRa链路在空间和时间维度上是否稳定？2)在城市环境中，每个网关可以覆盖多大的区域进行可靠的通信？3)通过LoRa链路定位端节点可以达到什么精度？根据我们的测量，我们的主要发现是：1）由于城市地区不同类型的土地覆盖和频繁的微环境变化，LoRa链路的空间和时间行为是非常动态的; 2）每个网关可以覆盖约11.3平方公里的区域和边际SNR增益（例如，2 dB）的LoRa链路足够有效，可以扩大32.6%的网关覆盖区域;以及3）。中位定位误差约为400 m。在没有密集部署的LoRa网关的情况下，SOTA LoRa本地化可以支持道路级本地化，即使终端节点靠近其中一个网关。
Internet-of-Things (IoT) aims to connect billions of low-date rate and energy-constrained end-devices in the near future. Although many IoT systems have been commercialized, most of them focus on home and body scale applications. To establish a low-cost IoT at the city scale, LoRa Wide Area Networks (LoRaWAN) have become attractive in recent years due to their desirable kilometer or even longer communication distance with low energy consumption. However, due to the expensive cost of densely deploying end-nodes, the understanding of LoRa link behavior is still coarse-grained, and hard to fully realize the link dynamics, networking coverage, and localization accuracy of LoRaWAN in an urban environment. This paper shows a fine-grained LoRa link-level measurement via mobile end-nodes. We deploy two gateways and six mobile end-nodes and collect data packets over four months at a $6\times 6\ km^{2}$ urban area. The evaluation mainly focuses on answering three questions: 1) Does a LoRa link stably perform in both spatial and temporal dimensions? 2) How large area can be covered for reliable communication by each gateway in the urban environment? 3) What accuracy can be achieved to localize an end-node through LoRa links? According to our measurement, our key findings are 1) The spatial and temporal behavior of LoRa links is quite dynamic due to the different types of land covers and the frequent micro-environment changes in the urban areas; 2) Each gateway can cover about 11.3 km2 area and marginal SNR gains (e.g., 2 dB) of LoRa links are efficient enough to enlarge 32.6% coverage area of a gateway; and 3). The median localization error is about 400 m. Without densely deployed LoRa gateways, the SOTA LoRa localization can support road-level localization, even when an end node is close to one of the gateways.