A Novel Energy-Efficient Routing Scheme for LoRa Networks

Although being simple and currently adopted for LoRaWAN, single-hop routing (i.e., direct transmission from end devices to the gateway) is not necessarily optimal in terms of minimizing the total energy consumption of the network. This paper extends Distance Ring Exponential Generator (DRESG) framework and presents a multi-hop routing scheme in the context of low-power wide-area networks (LPWANs) based on LoRa transmission technology. An evaluation framework is developed to analyze and compare different routing mechanisms that takes into account important factors such as the type of nodes in the network and node distribution. Considered are direct-hop (DH) routing, next-ring-hop (NRH) routing and variable-hop (VH) routing. Analysis and simulations results confirm that better performance in terms of energy efficiency is achieved with multi-hop routing model over single-hop routing. In particular, while maintaining a high level of network connectivity, VH routing outperforms DH routing by minimizing energy consumption of critical nodes. The gain in terms of energy saving or enhancing network lifetime becomes more significant with payload aggregation.