1. A method, comprising: equalizing by an apparatus, based on a pilot block, a group of data symbols for a current block of data symbols in a plurality of blocks received over a communication channel to generate a group of equalized symbols; de-rotating by the apparatus the group of equalized symbols as a function of a phase estimate to determine initial de-rotated equalized symbols, wherein the phase estimate is an estimate of phase caused by noise for blocks previous to the current block of data symbols; and calculating by the apparatus a phase metric from real and imaginary parts of the initial de-rotated equalized symbols in the group, wherein the phase metric estimates phase caused by noise for the current block; wherein the phase metric is calculated as a function of a sum of a plurality of products of the absolute value of the real and the imaginary parts of the initial de-rotated equalized symbols.