A Multi-Channel Software Decoder for the LoRa Modulation Scheme

Abstract

LoRa is a recently introduced modulation scheme specifically designed for Low-Power Wide-Area Networks. In this paper, we provide the first detailed and complete description of the LoRa PHY layer, and present a novel methodology for detecting and decoding LoRa frames using Software Defined Radios. Our proposed decoding approach can efficiently decode multiple channels simultaneously in software due to an invariance towards the signal frequency. Hence, our approach also removes the need for correcting frequency offset errors imparted by the transmitter or receiver. We have evaluated our decoding technique in a lab setup using three Software Defined Radios (USRP B210, HackRF, and RTL-SDR) and three commercial off-the-shelf hardware LoRa transceivers (Microchip RN2483, HopeRF RFM96, and Semtech SX1272). We show that our decoder is fully compatible with all configurations of the RN2483 and SX1272, achieving an overall packet error rate of 0 for a signal-to-noise ratio of 20 dB. The source code of the decoder and datasets used in the evaluation are made available publicly