Energy-Aware Relaying in Dense LoRa Networks With Heterogeneous Batteries.

We propose a relaying scheme for a LoRa network’s uplink, where some end devices (EDs) overhear and relay messages from other EDs. The scheme’s salient feature is that it allows the EDs to adjust their relaying behavior according to their energy status, such that EDs with higher energy reserves perform more forwarding. This prevents early depletion of batteries at the low-energy forwarders, while still achieving high reliability levels. The network is divided into tiers. Any ED in a given tier can relay message from any other ED in certain other tier; this eliminates the need for complicated relay-selection procedures. No synchronization requirement is imposed on the EDs. We demonstrate large reductions in the loss rate with just 10 % of the EDs acting as relays, operating within 1 % duty cycle.