Non-data-aided Joint Estimation of Time and Frequency Offset in OFDM Systems Using Channel Order Based Regression

Previously proposed non-data-aided time delay and carrier frequency offset estimators typically require multiple orthogonal frequency division multiplexing (OFDM) symbols to achieve good estimation performance, which is not well-suited for positioning, navigation, and timing (PNT) applications in which fast acquisition time is critical. In this paper, a novel non-data-aided joint time and frequency estimator for OFDM systems that uses only one complete OFDM symbol and knowledge of the channel order is presented. The estimation performance in terms of mean squared error and lock-in probability is compared to comparable estimators presented in the literature. It is shown through simulation that the proposed estimator performs better than comparable methods for low signal-to-noise ratio in Rayleigh fading channels, especially for higher order channels.