Patent ID: 7869551
Filing Date: 2011-01-11
Classification: H04L

Abstract:
1. A method comprising: receiving an OFDM symbol having a useful data portion and a cyclic prefix, wherein the useful data portion starts in the symbol at an actual useful data start point, and wherein processing of the symbol begins at a random sample in the symbol; performing a time synchronization function on the symbol, thereby obtaining a first estimated start point of the useful data portion in the symbol; executing a first FFT on the symbol using the first estimated start point to derive a first FFT window, wherein the first FFT produces a phase response and a magnitude response; executing a second FFT on the phase response from the first FFT, thereby producing an output; analyzing the output to determine a sample offset value; adjusting the first estimated start point using the sample offset value, thereby obtaining a second estimated start point of the useful data portion in the symbol; and deriving a second FFT window for use by the first FFT, wherein the second estimated start point is closer to the actual useful data start point than is the first estimated start point.