An Improved Demodulation for LoRa Through a Threshold-Based Detection of Error

Abstract

This paper deals with an improved demodulation technique for LoRa signal. The principle consists in detecting the possible errors of demodulation, by comparing the highest peak of the periodogram of the dechirped received signal weighted by a coefficient beta? smaller than one with the other peaks of the periodogram. If an error is detected, a second demodulation stage is processed at an oversampling rate (OSR) higher than the first demodulation stage. Otherwise, the result of the first demodulation is kept. A thorough performance analysis of the suggested technique, based on order statistics, is carried out, in terms of detection rate, error rate, and complexity. It is shown that beta? can be tuned to adjusts the trade-off between performance and complexity. Moreover, simulations results shows that it is possible, for relatively low signal-to-noise (SNR) values, to reach the performance of the demodulation at highest OSR while keeping the complexity of the demodulation at lowest OSR.