The effect of timing errors on frequency offset estimation in OFDM systems

This work considers the effect of timing errors on the carrier frequency offset (CFO) estimation for orthogonal frequency division multiplexing (OFDM) systems. In general, most of the research conducted on OFDM systems assume that a wide range of timing errors can be tolerated due to the use of cyclic prefix (CP). Although such assumption might be valid for bit error rate (BER) analysis, it might not be the case for other processes such as CFO estimation. In this work, Monte Carlo simulations have been used to evaluate the effect of timing errors on the performance of several state-of-the-art CFO estimators for OFDM systems. The considered estimators include time domain, frequency domain, data-aided (DA) and blind estimators. Simulation results confirmed that particular CFO estimators, which are known to be highly accurate in perfect timing conditions, are very sensitive to timing offsets even if the offsets are within the inter-symbol-interference (ISI) free region of the CP. Other estimators offered high robustness for timing offsets in the entire range of the CP region. However, most of the considered estimators suffered from a severe performance degradation for timing errors out of the CP region.