US Patent 7769074 Detecting and synchronizing to frequency hopped packets

Methods and systems for detecting and synchronizing to frequency hopped packets are presented. A technique for detecting a transmitter frequency hopping pattern includes receiving a packet of preamble symbols respectively transmitted over multiple frequency sub-bands according to the transmitter frequency hopping pattern, and partitioning predetermined frequency hopping patterns into disjoint groups of patterns, each group of patterns having an associated periodicity of the received preamble symbols. A group of patterns is selected by comparing a correlation metric of two received preamble symbols for each of the associated periodicities in a first selected frequency sub-band, and a pattern from the selected group of patterns is selected based on a timing of a detected first peak of the correlation metric in a second selected frequency sub-band. Optionally, the selected pattern is verified by comparing the correlation metric at a particular time interval to a threshold value in a third selected frequency sub-band.