Performance of a Frequency-Domain OFDM-Timing Estimator

A frequency-domain algorithm for OFDM-timing estimation is considered useful when the OFDM system is to operate in a known narrowband interference channel, e.g., in a cognitive radio OFDM-based overlay system. We generalize a recently proposed frequency-domain algorithm for OFDM-timing estimation and then analyze the performance of the algorithm. The algorithm is based on a complex timing metric that has the mean of which the angle depends in an affine manner on the time offset. By computing the mean of the metric and the mean square of the metric component orthogonal to the mean, from the power-delay profile and noise condition of the channel, the channel-induced bias of the estimator is quantified and the root-mean-square of the estimation error is estimated. The discrepancy between analysis and simulation results on the root-mean-square error is less than one nominal sampling interval for a useful range of operating conditions.