Slotted ALOHA on LoRaWAN - Design, Analysis, and Deployment

TL;DR

This paper introduces a Slotted-ALOHA overlay for LoRaWAN to enhance network throughput and scalability without modifying existing libraries, supported by hardware measurements and a synchronization service.

Contribution

It presents a novel Slotted-ALOHA approach with a synchronization scheme for LoRaWAN, improving throughput and reducing packet loss without requiring changes to existing protocols.

Findings

Significant throughput improvement over traditional LoRaWAN.

Reduced packet collision rate with the proposed method.

Effective synchronization service for low-cost sensor nodes.

Abstract

LoRaWAN is one of the most promising standards for long-range sensing applications. However, the high number of end devices expected in at-scale deployment, combined with the absence of an effective synchronization scheme, challenge the scalability of this standard. In this paper, we present an approach to increase network throughput through a Slotted-ALOHA overlay on LoRaWAN networks. To increase the single channel capacity, we propose to regulate the communication of LoRaWAN networks using a Slotted-ALOHA variant on the top of the Pure-ALOHA approach used by the standard; thus, no modification in pre-existing libraries is necessary. Our method is based on an innovative synchronization service that is suitable for low-cost wireless sensor nodes. We modelled the LoRaWAN channel with extensive measurement on hardware platforms, and we quantified the impact of tuning parameters on physical and medium access control layers, as well as the packet collision rate. Results show that Slotted-ALOHA supported by our synchronization service significantly improves the performance of traditional LoRaWAN networks regarding packet loss rate and network throughput.