Blind CFO estimation based on GSA for interleaved OFDMA uplink

This paper deals with carrier frequency offset (CFO) estimation for interleaved orthogonal frequency division multiple access (OFDMA) uplink systems. Firstly, gravitational search algorithm (GSA) with center-symmetric trimmed correlation matrix and multiple signal classification criterion is presented for the purpose of efficient estimation. It has been shown that the estimate accuracy of the searching-based estimator strictly depends on the number of search grids used during the peaks searching process, which is time consuming and the required number of search grids is not clear to determine. However, the searching grid size is no need to know previously for the proposed GSA-based approach. Meanwhile, the advantage of inherent interleaved OFDMA signal structure also is exploited to conquer the problems of local optimization and the effect of ambiguous peaks for the proposed estimators. Finally, several simulation results are provided for illustration and comparison.