Frequency Interval Modulation Scheme for Mobile LoRa Communications

In this letter, we consider a system based on LoRa (Long Range), which is one of the widely used IoT (Internet of Things) communication technologies. Recently, as the application areas of LoRa have expanded from low-speed to high-speed moving objects, an increase in error rates due to Doppler shift in high-speed environments has been reported. To address this issue, this letter proposes a new LoRa modulation scheme where information is conveyed by varying the frequency difference between two chirp signals. Additionally, an efficient demodulation algorithm is proposed to successfully demodulate information at the receiver even in the presence of residual carrier frequency offset. Numerical results demonstrate that the proposed LoRa modulation scheme can guarantee low error rates in mobile environments.