A Joint Timing Offset and Channel Estimation Using Fractional Fourier Transform and Cazac Sequences

This paper deals with symbol timing offset and channel estimation in OFDM (orthogonal frequency division multiplexing) system in fast varying channel. Symbol timing offset (STO) estimation is a major task in OFDM. Most of existing methods for estimating STO used cyclic prefix or training sequences. In this paper, we consider a new system for STO estimation using constant amplitude zero autocorrelation (CAZAC) sequences as pilot sequences in conjunction with fractional Fourier transform (FRFT). After STO estimation is done, timing compensation is made. Thereafter, channel is estimated to well recover the original transmitted signal. This method gives good results in terms of MSE in comparison with other known techniques, it estimated well the channel and it is important for fast varying channel. MATLAB Monte-Carlo simulations are used to evaluate the performance of the proposed estimator.