Time-slotted LoRa MAC with variable payload support
Anna Triantafyllou, Dimitrios Zorbas, Panagiotis Sarigiannidis
Abstract
LoRaWAN is an upcoming Low Power Wide Area Network (LPWAN) technology for Internet of Things \nimplementations in various application domains. Despite its various advantages, LoRaWAN employs an Alohabased \nMAC, which in terms of performance cannot guarantee high packet delivery ratio and low latency. \nTo overcome this issue, we propose a time-slotted scheme, called TS-VP-LoRa, which supports multiple \ntransmission times and packet sizes at the same time. In TS-VP-LoRa, scheduling is coordinated by the LoRa \ngateway, broadcasting beacon frames periodically for the synchronization of LoRa end-devices. A channel \nhopping mechanism is also proposed in order to minimize the occurrence of collisions and to evenly split \nthe transmission load among all channels. TS-VP-LoRa is evaluated and compared to three other MAC-layer \nschemes in single gateway simulation scenarios with up to 500 nodes. The proposed scheme has proven to \nachieve low latency with high packet delivery ratios, significantly minimize collisions and maintain a relatively \nlow energy consumption despite the scaling of the LoRa network.