Haxhibeqiri Jetmir, Van den Abeele Floris, Moerman Ingrid, Hoebeke Jeroen
Department of Information Technology, Ghent University-imec, IDLab, Technologiepark-Zwijnaarde 15, B-9052 Ghent, Belgium.
Sensors (Basel). 2017 May 23;17(6):1193. doi: 10.3390/s17061193.
LoRa is a long-range, low power, low bit rate and single-hop wireless communication technology. It is intended to be used in Internet of Things (IoT) applications involving battery-powered devices with low throughput requirements. A LoRaWAN network consists of multiple end nodes that communicate with one or more gateways. These gateways act like a transparent bridge towards a common network server. The amount of end devices and their throughput requirements will have an impact on the performance of the LoRaWAN network. This study investigates the scalability in terms of the number of end devices per gateway of single-gateway LoRaWAN deployments. First, we determine the intra-technology interference behavior with two physical end nodes, by checking the impact of an interfering node on a transmitting node. Measurements show that even under concurrent transmission, one of the packets can be received under certain conditions. Based on these measurements, we create a simulation model for assessing the scalability of a single gateway LoRaWAN network. We show that when the number of nodes increases up to 1000 per gateway, the losses will be up to 32%. In such a case, pure Aloha will have around 90% losses. However, when the duty cycle of the application layer becomes lower than the allowed radio duty cycle of 1%, losses will be even lower. We also show network scalability simulation results for some IoT use cases based on real data.
LoRa是一种长距离、低功耗、低比特率的单跳无线通信技术。它旨在用于物联网（IoT）应用中，这些应用涉及对吞吐量要求较低的电池供电设备。一个LoRaWAN网络由多个与一个或多个网关通信的终端节点组成。这些网关充当通向公共网络服务器的透明桥梁。终端设备的数量及其吞吐量要求将对LoRaWAN网络的性能产生影响。本研究调查了单网关LoRaWAN部署中每个网关的终端设备数量方面的可扩展性。首先，我们通过检查干扰节点对发送节点的影响，用两个物理终端节点确定技术内干扰行为。测量结果表明，即使在并发传输情况下，在某些条件下仍可接收其中一个数据包。基于这些测量结果，我们创建了一个用于评估单网关LoRaWAN网络可扩展性的仿真模型。我们表明，当每个网关的节点数量增加到1000时，丢包率将高达32%。在这种情况下，纯Aloha的丢包率将约为90%。然而，当应用层的占空比低于允许的1%的无线电占空比时，丢包率会更低。我们还展示了基于实际数据针对一些物联网用例的网络可扩展性仿真结果。
