Systems and methods for joint beamforming and preamble detection
First Claim
1. A Radio Frequency Identification (RFID) reader system including an RFID receiver, the RFID receiver comprising:
- an antenna array comprising a plurality of antenna elements;
a joint beamformer and preamble detector configured to receive inputs from each of the plurality of antenna elements, where the joint beamformer and preamble detector is configured to;
correlate the inputs from the plurality of antenna elements against a correlation sequence at a plurality of starting sample positions and a plurality of predetermined rates;
use the correlations to select a starting sample position and rate for decoding the received signal;
use the correlations to determine beamforming coefficients for combining the inputs from each of the plurality of antenna elements;
combine the inputs from each of the plurality of antenna elements using the determined beamforming coefficients; and
resample the combined inputs from each of the plurality of antenna elements based upon the selected starting sample position and rate; and
a decoder configured to receive the resampled signal from the joint beamformer and preamble detector and to decode data using the resampled signal.
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Abstract
Systems and methods for reading RFID tags using joint beamforming and preamble detection in accordance with embodiments of the invention are disclosed. One embodiment includes an antenna array comprising a plurality of antenna elements, a joint beamformer and preamble detector configured to receive inputs from each of the antenna elements, and a decoder configured to receive a resampled signal from the joint beamformer and preamble detector and to decode data using the resampled signal. In addition, the joint beamformer and preamble detector is configured to correlate the inputs from the antenna elements against a correlation sequence at a plurality of starting sample positions and predetermined rates, use the correlations to select a starting sample position and rate for decoding the received signal, use the correlations to determine beamforming coefficients for combining the inputs, and resample the combined inputs based upon the selected starting sample position and rate.
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Citations
16 Claims
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1. A Radio Frequency Identification (RFID) reader system including an RFID receiver, the RFID receiver comprising:
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an antenna array comprising a plurality of antenna elements; a joint beamformer and preamble detector configured to receive inputs from each of the plurality of antenna elements, where the joint beamformer and preamble detector is configured to; correlate the inputs from the plurality of antenna elements against a correlation sequence at a plurality of starting sample positions and a plurality of predetermined rates; use the correlations to select a starting sample position and rate for decoding the received signal; use the correlations to determine beamforming coefficients for combining the inputs from each of the plurality of antenna elements; combine the inputs from each of the plurality of antenna elements using the determined beamforming coefficients; and resample the combined inputs from each of the plurality of antenna elements based upon the selected starting sample position and rate; and a decoder configured to receive the resampled signal from the joint beamformer and preamble detector and to decode data using the resampled signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of detecting data transmitted by a Radio Frequency Identification (RFID) tag in an RFID receiver comprising an antenna array and a joint beamformer and preamble detector, the method comprising:
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receiving sampled streams from each antenna element in the antenna array within the RFID receiver; correlating each of the sampled streams against a predetermined correlation sequence at a plurality of possible starting sample positions and a plurality of predetermined rates within the joint beamformer and preamble detector; summing the magnitudes of the correlation values of each of the sample positions and rates across each of the antenna streams within the joint beamformer and preamble detector; selecting the starting sample position and rate having the highest sum of correlation value magnitudes within the joint beamformer and preamble detector; determining beamforming coefficients based on the correlations of each of the streams at the selected starting sample position within the joint beamformer and preamble detector; combining the antenna streams using the determined beamforming coefficients within the joint beamformer and preamble detector; resampling the combined antenna streams based upon the selected starting sample position and rate, within the joint beamformer and preamble detector, to produce a resampled signal; and decoding the transmitted data from the resampled signal within the RFID receiver.
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Specification