Efficient four-quadrant carrier frequency offset tracking for OFDM

Abstract

We modify a LC-CFO estimator in the literature to make it easier to implement. By using the Lagrange interpolation, three low-order functions are used as candidates for replacing the arctangent function used in the LC-CFO estimator. The simplest one among these low-order functions sets its output directly equal to its input. In consequence, up to 20 iterations are needed for convergence with the carrier frequency offset up to 0.5. Moreover, the steady-state mean square errors are very close to the Cramer–Rao bounds at median-to-high signal-to-noise ratios. Those performances are about the same as when using a conventional LC-CFO estimator.

Keywords:

• Orthogonal frequency-division multiplexing
• carrier frequency offset
• maximum likelihood estimation