SNR optimized residual frequency offset compensation for WiMAX with throughput evaluation

WiMAX with an OFDM physical layer employed is sensitive to carrier frequency offset. Even though most of this offset can be compensated with the initial training sequence, there still remains a residual frequency offset due to estimation errors. In this paper, we investigate pilot-based and data-aided residual frequency offset estimators and apply them to WiMAX. To improve the pilot-based method, we propose two compensation schemes which exploit the a-priori knowledge from the previous frame. For the data-aided method with general QAM schemes, the optimal weighting factors that maximize the SNR after combining are analytically derived. Throughput results show that most of the degradation due to the residual frequency offset can be compensated by our proposed low-complexity suboptimal methods.