Coherent Multi-Channel Ranging for Narrowband LPWAN: Simulation and Experimentation Results

Precise radio based positioning for low power wide area networks remains a challenging research area due to narrowband signals and multipath propagation. Multi-channel ranging provides improved temporal resolution by coherent processing. While this technique has been applied to short range radio standards, no experimental demonstration for long range radio devices exists. The present paper introduces a hardware testbed for phase coherent multi-channel processing of narrowband signals. Simulations and preliminary experimental multi-channel results show a higher ranging precision (factor 20) over time based ranging. In a frequency flat channel with a 10 kHz signal, precisions down to 10 m (phase based) and 200 m (time based) have been achieved. Precision degrades in multipath propagation scenarios.