期刊名称：International Journal of Distributed Sensor Networks
印刷版ISSN：1550-1329
电子版ISSN：1550-1477
出版年度：2020
卷号：16
期号：12
页码：1
DOI：10.1177/1550147720979279
出版社：Hindawi Publishing Corporation
摘要：LoRa/LoRaWAN is growing rapidly as an underlying technology for the Internet of Things because of its long-range connectivity and low power. However, its limited scalability, owing to spread spectrum–based modulation and contention-based medium access control, impedes its use in emerging massive applications. In this study, we propose a downlink transmission scheme for enhancing the scalability of LoRa networks. The proposed scheme consists of two mechanisms. First, a modulation parameter is adjusted using the different transmission power limitations between the gateways and end devices to reduce downlink duration. Second, the timing of downlink traffic is selected based on uplink traffic concentration analysis. The proposed scheme reduces the uplink failure, and consequently, allows more end devices to participate in the network. The simulation results show that the proposed scheme is superior to the standard protocol in terms of the packet delivery ratio.
关键词：Congestion control; Internet of Things; LoRa/LoRaWAN; packet delivery ratio; scalability
