Iterative Based Time Domain Equalization Method for OFDM Signal under High Mobile Environments

A loss of subcarrier orthogonality in orthogonal frequency division multiplexing (OFDM) signal due to timevarying multipath fading channel causes an inter-carrier interference (ICI) which would lead fatal degradation of bit error rate (BER) performance. To solve this problem, this paper proposes a high accuracy time domain channel impulse response (CIR) estimation method and a time domain equalization (TDE) method of using estimated CIR at every sampling time in conjunction with a low-complexity iterative method instead of using an inverse matrix calculation. The salient feature of proposed method is to employ a time-domain training sequence (TS) for the estimation of CIR at every sampling time and lowcomplexity iterative method for solving the simultaneous equations which are required in the TDE method. This paper presents various simulation results to demonstrate the effectiveness of proposed TDE method as comparing with the conventional frequency domain equalization (FDE) method.