Unbiased timing error estimation in the presence of non-ideal interpolation

We propose a method to eliminate the bias term present in the timing error estimator employed in digital receivers where the input signal is sampled by a fixed clock that is not synchronized to the transmitter clock. This bias error results from the non-ideal interpolation that precedes the timing error estimator. We show that it can be derived as a function of the previously estimated symbol timings. An unbiased timing error estimate can then be obtained by subtracting this bias term from the output of the timing error detector. Simulation results are included to show the performance improvement realizable by employing this method