Robust Timing Offset Estimation Using Sub-autocorrelation Functions for Uni- and Bi-directional Chirp Signals

In this paper, we present a robust timing offset estimation method using sub-autocorrelation functions for uni- and bi-directional chirp signals. The presented timing offset estimator is designed to be applied with a generalized chirp signal sequence, which use uni- or bi-directional chirp symbols. Using the conjugate property of the chirp signal, the sub-autocorrelation functions are generated to be applied with the received chirp signals and the resulting performance is improved. Conventional timing offset estimators are difficult to apply to IEEE 802.15.4a and ISO/IEC 24730-5 systems because spurious peaks are generated near the arrival time of the true signal. The conjugate and symmetric properties between uni- and bi-directional chirp signals are exploited to improve the performance of the timing offset estimator. The performance analysis of the proposed scheme is presented in terms of the root mean square error (RMSE) obtained by Monte-Carlo simulations. The simulation results indicate that the proposed estimator has a smaller RMSE than other conventional estimators.