MoRa: A LoRa-Based System for Timely and Energy-Efficient e-Price Tag Update in Markets

While numerous wireless applications are emerging to simplify our daily life, updating price tags in large-scale markets is still largely performed manually. Considering the potential adoption of electronic price (e-price) tags, we propose MoRa, a LoRa-based system for timely and energy-efficient price update in Markets. By leveraging the category information in the market, we design a hierarchical address scheme. Based on the scheme, we can perform efficient multicast with nearly zero overhead in group joining and activity scheduling. Furthermore, considering LoRa's characteristics and the asymmetry between the gateway and nodes, we let the gateway make fast and repetitive transmissions before the uncovered nodes send light weight NAKs. Extensive testbed experiments and simulation evaluations are conducted. Results demonstrate that MoRa can efficiently improve the performance in terms of update delay and energy consumption.