Frequency Offset Estimation of Chirp Modulation

Chirp spread spectrum technology has attracted much attention because it has low complexity, low power consumption, good anti-multipath and anti-interference ability, which can be used in smart grid communication system. This paper describes the mathematical model of chirp modulation and demodulation, analyzes the influence of frequency offset on the performance of chirp demodulation under different spreading factors (SF), then we propose and analyze a frequency offset estimation algorithm based on Fast Fourier Transform (FFT) and the relationship between the SF of preamble symbols and the SF of data symbols when the demodulation performance loss is relatively small. Finally, simulation results show that compensation based on the estimated frequency offset can improve the demodulation performance and coverage distance of chirp modulation.