LLNRM: LoRaWAN Loss Node Relay Mechanism for Smart Cities

In smart-city scenarios, the high density of buildings and nodes poses significant challenges to the Quality of Service (QoS) in LoRaWAN communications, resulting in frequent data loss and degraded network performance. This paper introduces the LoRa Loss Node Relay Mechanism (LLNRM), a novel solution designed to enhance the reliability of LoRaWAN networks in urban environments. LLNRM addresses signal attenuation and data transmission failures caused by dense infrastructure by categorizing nodes based on their data loss levels and leveraging geographically closest neighbors to relay data from nodes with total loss to gateways. Through extensive NS3 simulations, LLNRM demonstrates a significant improvement in Packet Delivery Ratio (PDR) in high-density, multi-gateway deployments, outperforming the standard Adaptive Data Rate (ADR) mechanism without requiring modifications to the Spreading Factor (SF). Our results show an enhancement of over <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 0 \%}$</tex> compared to a geographical-based solution and nearly 40 % compared to ADR. These findings highlight LLNRM's potential to significantly boost network performance in smart-city applications.