Patent ID: 8406353

Claim:
A method comprising: at a wireless communication device, receiving energy in a frequency band and generating a receive signal representing the received energy; dividing the receive signal into windows of a predetermined time duration; computing a running auto-correlation of the receive signal to produce an auto-correlation sequence for a sequence to be detected in the receive signal; generating data representing a mask for a window based on the receive signal by computing a correlation vector for a window of the receive signal based on partially overlapping samples of the receive signal, computing first and second power values from the correlation vector corresponding to at least two peaks in the correlation vector, which at least two peaks are indicative of the presence of the sequence in the receive signal, comparing the first and second power values with each other, and setting a pass value for the mask when the first power value is greater than the second power value and otherwise setting a reject value for the mask; applying the mask to the auto-correlation sequence to filter out portions of the auto-correlation sequence that are outside of the mask; and detecting a position of a sequence in the receive signal based on a position of a peak in the auto-correlation sequence after application of the mask.