Timemaps for Improving Performance of LoRaWAN

Abstract

In this paper, we propose Timemaps, a new scheduling scheme to improve the performance of LoRaWAN. The idea is to build a temporal map of all transmissions of IoT devices by a Gateway to schedule transmissions and avoid collisions. A device when performing a Join operation includes its traffic description in the request. Based on the traffic descriptions from all devices, the Gateway constructs a schedule for channel access that avoids collisions. The Gateway includes in the Join accept the information on the temporal position of the device transmission in the schedule, the Spreading Factor (SF) to use based on measured Signal to Noise Ratio (SNR) at the Gateway, and the channel to use. We evaluate our proposal with the NS-3 simulator in both cases of perfect clocks and clocks with a drift as well as for homogeneous and inhomogeneous node density. The simulation takes into account quasi-orthogonality and the capture effect. The results show that Timemaps benefits from remarkably higher PDR and a considerably lower collision ratio compared to LoRaWAN along with slightly increased energy consumption.