Mesh Augmentation of LoRaWAN-based IoT Networks

TL;DR

LIMA is a mesh protocol that enhances LoRaWAN networks by increasing coverage and reducing device energy use through multi-hop routing without altering existing standards.

Contribution

It introduces LIMA, a mesh extension for LoRaWAN that improves range and energy efficiency with no changes to end devices or the standard.

Findings

LIMA increases delivery rate, scalability, and reduces energy consumption significantly.

Simulation results show up to 5x delivery rate and 12.6x energy savings.

Prototype testing confirms practical deployment and performance gains.

Abstract

LoRaWAN is a leading standard and technology for low-power, long-range Internet-of-Things (IoT) communications. However, its single-hop architecture results in limited effective range and excessive power consumption for end devices, especially when deployed in large, remote and RF-challenged environments. Existing solutions are either incompatible with LoRaWAN, or limit relaying to a single hop. We present LIMA, a protocol for augmenting an existing or new LoRaWAN deployment with a mesh network of LIMA Routers. LIMA increases the effective coverage range well beyond the maximum LoRa range via multi-hopping, and significantly reduces the energy consumed by end-devices. LIMA requires no changes to the end-device, the servers or the LoRaWAN standard. LIMA builds routes using reverse path forwarding, tunnels LoRaWAN messages over LIMA, provides transparent extension of the existing Adaptive Data Rate (ADR), and suppresses duplicate forwarding if the device is directly reachable from the Gateway. Simulations using Network Simulator 3 (ns-3) show that LIMA increases the delivery rate, scalability, ED energy consumption by up to 5x, 8x and 12.6x respectively, and reduces latency by up to 2.3x. Table-top and outdoor testing with a prototype constructed using a commercial gateway as a starting point confirm that LIMA can be successfully deployed within an existing LoRaWAN system, and can provide range and energy gains transparently.