Experimental and analytical studies on a high-resolution OFDM carrier frequency offset estimator

In orthogonal frequency-division multiplexing (OFDM) communications, carrier frequency offset must be estimated and compensated at the receiver to maintain orthogonality. In this paper, we examine the performance of a blind carrier frequency offset estimation algorithm for OFDM communications. Experiments were conducted on a system operating at close to 2 MBits/s. Insights obtained from these experiments provided the motivation to explore the fundamental relationships between estimator performance and multiple system parameters such as the signal-to-noise ratio, number of data samples, frequency-selective fading, and power loading. We examine the sensitivity of the blind carrier frequency offset estimation algorithm using first-order perturbation analysis. In particular, we derive a closed-form expression for the mean square error of the carrier frequency offset estimator and present tradeoff studies for the high-resolution blind estimator performance. The analytical and simulation studies are in good agreement with experimental results.