Cyclic Prefix Based Symbol Timing Synchronization Method for OFDM Systems by Using the Correlation Property of Preamble

In this paper, an improved and effective estimation method for orthogonal frequency division multiplexing (OFDM) symbol timing synchronization is proposed. This maximum likelihood estimation (MLE) based method takes advantage of (cyclic prefix) CP along with the conventional training sequence, which consists of four identical parts (but the last two parts with different sign). By exploring the multivariate Gaussian distribution within the OFDM preamble symbol as well as corresponding CP, the accuracy of symbol timing error estimation can be significantly enhanced due to its smaller estimation variance. The performance of the proposed method is validated and compared with existing estimation (and synchronization) methods in terms of timing metric and mean square error (MSE) under AWGN, Rayleigh flat fading and frequency-selective multipath Rayleigh fading environments, respectively. Computer simulation results confirm the effectiveness of the proposed method under various levels of signal to noise ratio (SNR).