Blind residual CFO estimation with computational efficiency for interleaved OFDMA uplink systems

Abstract

This paper deals with simple and effective residual carrier frequency offsets (CFO) estimation approaches for interleaved orthogonal frequency division multiple access (OFDMA) uplink systems. It has been shown that the propagator method (PM) has low computational load and is efficient in noise free environments. However, the PM is not robust to noise. With the forward-backward (FB) correlation matrix and PM, the searching-based FBPM estimator can improve the CFO estimate accuracy. In order to alleviate the noise effect, we also aim firstly at demonstrating the usefulness of QR and LU factorizations of the FB correlation matrix for FBPM with to construct the U-FBPM and R-FBPM estimators, respectively. Next, relative high accuracy and low-complexity to the CFO estimation can be achieved by the polynomial rooting scheme. Finally, several simulation results are provided for illustration and comparison.