Multi-Frequency Phase Difference of Arrival for Precise Localization in Narrowband LPWA Networks

In Low Power Wide Area (LPWA) networks, radio localization based on Time Difference of Arrival measurements has major benefits: energy consumption of the node and spectrum usage are contained. Temporal resolution and hence positioning accuracy is however limited by the bandwidth of the LPWA narrowband signals. Multi-channel ranging, that relies on multiple narrowband signals that are sequentially transmitted on different and discontinuous channels, has recently been proposed to improve precision. However, the concept has not been adapted yet to differential uplink localization techniques. This paper studies and proposes adaptations to multi-channel ranging called Multi-Frequency Phase Difference of Arrival (MF-PDoA) for this purpose. It analyzes the impact of imperfect synchronization on its performance and concludes that MF-PDoA is robust and well adapted to the LPWA scenario.