Carrier Frequency Offset Estimation Based on Twice FFT Matrix Algorithm

There is a contradiction between the estimation range and estimation accuracy of the most carrier frequency offset (CFO) estimation algorithms. In order to solve the dilemma, this paper proposes an improved Fast Fourier Transform (FFT) CFO estimation method based on Twice FFT Matrix Algorithm (TFMA). The idea of the method is to ameliorate the frequency resolution highly by enlarging the size of FFT, without sacrificing the estimation range. By the application of TFMA, the calculation resource consumption is decreased largely compared with the direct implementation of large-size FFT in the field programmable gate array (FPGA). Therefore, the approach can be used to estimate the large CFO of the high-order modulation signals accurately and effectively. The experiment results verify that the method can complete the estimation of the small or large CFO precisely, thus the contradiction above has been solved properly. Moreover, TFMA has been realized on the hardware platform of FPGA.