Method and apparatus with improved estimation accuracy and robustness for fine frequency offset estimation in coherent receivers

摘要

The present disclosure provides a method and system for fine estimation of a local oscillator frequency offset of a received signal at a coherent receiver, by evaluating the probability mass function (PMF) of the signal phase of output symbols at different frequencies. At frequencies other than the actual frequency offset, the signal phase is uniformly distributed in [−π,π] such that the summation of a function of PMF values where the function is convex or concave between 0 and 1 can be utilized to determine an a frequency offset to be used by the coherent receiver.

主权项

1. A method for estimating a frequency offset of a signal received at a coherent receiver, comprising:
receiving a plurality of equalized symbols; processing a probability mass function (PMF) of the plurality of equalized symbols to provide a summation of a function of PMF values at each of a plurality of frequencies where the function is one of a strictly concave function between 0 and 1, and a strictly convex function between 0 and 1; identifying one frequency from the plurality of frequencies based on the summation of the function of the PMF values; and setting the frequency offset of the coherent receiver to the identified frequency.