Iterative OFDM receiver with channel estimation and frequency-offset compensation

In this paper, using the turbo principle, different iterative receiver designs are proposed for orthogonal frequency division multiplexing (OFDM) systems under a time-varying channel environment. In the presence of carrier frequency offset (CFO) error, the iterative receiver can improve the performance as better channel estimation and CFO compensation are available through iterations. The mitigation of the CFO is carried out via the two proposed methods - time domain compensation (TDC) and frequency domain cancellation which uses a decision feedback equalizer (DFE-FDC). The complexity of the DFE-FDC method is higher than that of the TDC approach as more operations are required to update the DFE coefficients. However, our simulation results show that the DFE-FDC outperforms the TDC for each iteration.