A simple and efficient timing offset estimation for OFDM systems

A simple timing offset estimation method for orthogonal frequency division multiplexing (OFDM) systems as a modification to Schmidl and Cox's method (see IEEE Trans. on Comms., vol.45, no.12, p.1613-21, 1997) is presented. By designing the training symbol, the timing metric plateau inherent of Schmidl et al. is eliminated and hence the performance is improved. The performances of the proposed method and of Schmidl et al. are evaluated by computer simulation in terms of the estimator variance. The timing offset estimator of Landstrom, Wilson, van de Beek, Odling and Borjesson (see Proc. Intl. Conf. on Communications, Vancouver, BC, Canada, p.500-5, 1999) is also included in the performance comparison as another reference. The simulation results show that the proposed method achieves significantly smaller estimator variance. Using more samples in calculation of the half symbol energy required in the timing metric is shown to give more robustness against a dispersive channel.