An algorithm for calibration of TDS-OFDM carrier frequency offset

Abstract

A synchronous algorithm applicable for time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) carrier frequency offset (CFO) is proposed in the thesis. This algorithm is based on pseudonoise (PN) sequence and two kinds of maximum likelihood estimation (MLE) algorithms are employed in frequency offset estimation. The first MLE could be implemented by fast Fourier transform (FFT), which is applicable for the calibration of integral frequency offset. The second MLE algorithm is employed in the estimation of decimal frequency offset. Although the MLE themselves are very common, these two MLE algorithms could compensate the deficiencies of each other, and could obtain satisfying results. The Cramer-Rao (CRO) lower bound of the algorithm is deduced in the thesis so as to evaluate the performance of the algorithm. According to the simulation results, even if under the circumstances of a very low SNR, the estimations on different frequency offsets are close to the CRO lower bound.