Patent ID: 9268981
Filing Date: 2016-02-23
CPC Classification: G06K

Claim Text:
1. A method of detecting transmitted data from a Radio Frequency Identification (RFID) tag using an RFID receiver, the method comprising: receiving sampled antenna streams from each of a plurality of antenna elements in an antenna array using the RFID receiver comprising the antenna array and a joint beamformer and preamble detector; generating correlation values by correlating each of the sampled antenna streams against a predetermined correlation sequence for each of a plurality of different possible starting sample positions at a plurality of different predetermined rates using the joint beamformer and preamble detector; summing magnitudes of the correlation values of each of the sample positions and rates across each of the sampled antenna streams using the joint beamformer and preamble detector; selecting the sample position and rate having a highest sum of the correlation value magnitudes using the joint beamformer and preamble detector; determining beamforming coefficients based on the correlation values of each of the sampled antenna streams at the selected sample position and rate using the joint beamformer and preamble detector; combining the sampled antenna streams based upon the determined beamforming coefficients using the joint beamformer and preamble detector; resampling the combined sampled antenna streams based upon the selected starting sample position and rate using the joint beamformer and preamble detector to produce a resampled signal; and decoding the transmitted data based upon the resampled signal using the RFID receiver.