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US 7,453,956 B2Granted
Apparatus, methods and computer program products for signal acquisition using common demodulation templates
AssigneeSony Ericsson Mobile Communications AB
InventorWilliam O. Camp, Jr.
Life of this patent
Estimating the term…
Abstract
A target modulation is detected in a signal, e.g., a radio signal received by a device such as a mobile communications terminal. Respective target modulation correlations for respective carrier timing hypotheses are determined by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template and detecting the target modulation from the target modulation correlations. The target modulation may be, for example, a pseudonoise (PN) code, such as a GPS code or a CDMA communications system code, and the carrier timing hypotheses may correspond to various potential Doppler shifts.
Claims35
A method of searching for a target modulation in a signal, the method comprising performing the following for each of a plurality of hypothetical carrier timings:
- shifting signal values corresponding to the signal according to a relationship between the hypothetical carrier timing and a reference carrier timing by augmenting or reducing a set of signal values according to the relationship between the hypothetical carrier timing and a reference carrier timing;
- demodulating the shifted signal values according to the reference carrier timing to produce demodulated signal values;
- shifting the demodulated signal values according to the relationship of the hypothetical carrier timing and the reference carrier timing by augmenting or reducing a set of demodulated signal values according to the relationship of the hypothetical carrier timing and the reference carrier timing;
- and
- determining a correlation of the shifted demodulated signal values with the target modulation,
- wherein the method further comprises detecting the target modulation responsive to the determined correlations for the hypothetical carrier timings.
3 more elements
A method of searching for a target modulation in a signal, the method comprising:
- determining respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template;
- and
- detecting the target modulation from the target modulation correlations,
- wherein determining respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template comprises:
- generating respective carrier demodulation templates for the respective carrier timing hypotheses from a common set of kernel templates based on relationships between the respective carrier timing hypotheses and a reference carrier timing;
- and
- determining the respective target modulation correlations for the respective carrier timing hypotheses using respective ones of the carrier demodulation templates.
4 more elements
An apparatus for searching for a target modulation in a signal, the apparatus comprising:
- means for determining respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template;
- and
- means for detecting the target modulation from the target modulation correlations,
- wherein the means for determining respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template comprises:
- means for generating respective carrier demodulation templates for the respective carrier timing hypotheses from a common set of kernel templates based on relationships between the respective carrier timing hypotheses and a reference carrier timing;
- and
- means for determining the respective target modulation correlations for the respective carrier timing hypotheses using respective ones of the carrier demodulation templates.
4 more elements
A GPS-enabled device, comprising:
- a radio processor configured to convert a radio signal to an intermediate frequency (IF) signal values;
- and
- a correlation processor configured to determine respective PN code correlations for respective IF timing hypotheses using a common IF demodulation template and to detect the target modulation from the target modulation correlations,
- wherein the correlation processor is operative to generate respective IF demodulation templates for the respective carrier timing hypotheses from a common set of kernel templates based on relationships between the respective IF timing hypotheses and a reference IF timing and to determine the respective PN code correlations for the respective IF timing hypotheses using respective ones of the IF demodulation templates.
1 more element
A computer program product for searching for a target modulation in a signal, the computer program product comprising computer program code embodied in a computer readable medium, the program code comprising:
- program code configured to determine respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template;
- and
- program code configured to detect the target modulation from the target modulation correlations,
- wherein the program code configured to determine respective target modulation correlations for respective carrier timing hypotheses by demodulating signal values corresponding to the signal for the respective carrier timing hypotheses using a common carrier demodulation template comprises:
- program code configured to generate respective carrier demodulation templates for the respective carrier timing hypotheses from a common set of kernel templates based on relationships between the respective carrier timing hypotheses and a reference carrier timing;
- and
- program code configured to determine the respective target modulation correlations for the respective carrier timing hypotheses using respective ones of the carrier demodulation templates.
4 more elements
An apparatus for searching for a target modulation in a signal, the apparatus comprising:
- means for performing the following for each of a plurality of hypothetical carrier timings:
- shifting signal values corresponding to the signal according to a relationship between the hypothetical carrier timing and a reference carrier timing by augmenting or reducing a set of signal values according to the relationship between the hypothetical carrier timing and a reference carrier timing;
- demodulating the shifted signal values according to the reference carrier timing to produce demodulated signal values;
- shifting the demodulated signal values according to the relationship of the hypothetical carrier timing and the reference carrier timing by augmenting or reducing a set of demodulated signal values according to the relationship of the hypothetical carrier timing and the reference carrier timing;
- and
- determining a correlation of the shifted demodulated signal values with the target modulation;
- and
- means for detecting the target modulation responsive to the determined correlations for the hypothetical carrier timings.
5 more elements
Dependencies are inferred from the claim text.