Two step synchronization procedure for orthogonal frequency division multiplexing (OFDM) receivers

Abstract

A method is disclosed to determine fine time synchronization in an OFDM digital receiver, as is receiver that operates in accordance with the method. The method includes buffering in a buffer normalized auto-correlation values derived from received OFDM signal samples and processing the buffered values by selecting first synchronization instants using a first selection window having a width of j samples, and selecting second synchronization instants using a second selection window having a width of k samples, where k<j, and where the second selection window is centered on an average timing computed as a result of the processing that occurred using the first selection window. In a preferred but non-limiting embodiment of this invention j=96 samples and k=16 samples. The buffering step includes first auto-correlating received signal samples to generate correlation peaks corresponding ideally only to cyclic prefix fields occurring within a received OFDM packet, normalizing the correlation peaks as a function of signal energy and storing signal samples in the buffer memory that include samples that correspond to the normalized correlation peaks. The OFDM receiver may form a part of a Multiple-Input, Multiple Output (MIMO) receiver that has a plurality of receive antennas. In this case the steps of buffering and processing occur in parallel for each of the plurality of receive antennas.

Dependencies are inferred from the claim text.