Decoding Superposed LoRa Signals

• Published in: 2018 IEEE 43rd Conference on Local Computer Networks (LCN) pp. 184 - 190
• Main Authors: Rachkidy, Nancy El, Guitton, Alexre, Kaneko, Megumi
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.10.2018
• Subjects: Bit rate; Chirp; Decoding; desynchronized signals; Interference cancellation; LoRa; LoRaWAN; LPWAN; Receivers; Synchronization; synchronized signals; Time-frequency analysis; Transmitters
• DOI: 10.1109/LCN.2018.8638253

Long-range low-power wireless communications, such as LoRa, are used in many IoT and environmental monitoring applications. They typically increase the communication range to several kilometers, at the cost of reducing the bitrate to a few bits per seconds. Collisions further reduce the performance of these communications. In this paper, we propose two algorithms to decode colliding signals: one algorithm requires the transmitters to be slightly desynchronized, and the other requires the transmitters to be synchronized. To do so, we use the timing information to match the correct symbols to the correct transmitters. We show that our algorithms are able to significantly improve the overall throughput of LoRa.