Method and apparatus for robust frequency tracking in strong channel interference using carrier signal relative strength and frequency error
AssigneeInternational Business Machines Corporation
InventorsMatthew C. Millward, Prasanna Desai
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Abstract
The present invention is a method and apparatus for tracking a frequency of a signal. The received signal is converted to an intermediate frequency (IF) signal using a frequency reference. An automatic gain control (AGC) is provided to the IF signal. The AGC generates a control value. The magnitude and phase parameters of the IF signal are estimated. A frequency error is estimated based on the phase parameter. A control quantity is generated based of the control value, the estimated magnitude parameter and the estimated frequency error. The control quantity adjusts the frequency reference.
Claims39
A method comprising:
- converting a received signal to an intermediate frequency (IF) signal using a frequency reference;
- providing an automatic gain control (AGC) to the IF signal, the AGC generating a control value;
- estimating magnitude and phase parameters of the IF signal;
- estimating a frequency error based on the phase parameter;
- generating a control quantity to adjust the frequency reference, the control quantity being based on the control value, the estimated magnitude parameter, and the estimated frequency error.
An apparatus comprising:
- a converter for converting a received signal to an intermediate frequency (IF) signal using a frequency reference;
- an automatic gain control (AGC) processor coupled to the converter for providing an AGC to the IF signal, the AGC processor generating a control value;
- a parameter estimator coupled to the converter for estimating magnitude and phase parameters of the IF signal;
- a frequency error estimator coupled to the parameter estimator for estimating a frequency error based on the phase parameter;
- and
- an automatic frequency tracker and controller (AFTC) coupled to the parameter and frequency error estimators for generating a control quantity to adjust the frequency reference, the control quantity based on the control value, the estimated magnitude parameter and the estimated frequency error.
A system comprising:
- a receiver for receiving a signal transmitted from a base station;
- and
- a communication unit for tracking a frequency of the signal, the communication unit comprising:
- a converter for converting the received signal to an intermediate frequency (IF) signal using a frequency reference,
- an automatic gain control (AGC) processor coupled to the converter for providing an AGC to the IF signal, the AGC processor generating a control value,
- a parameter estimator coupled to the converter for estimating magnitude and phase parameters of the IF signal,
- a frequency error estimator coupled to the parameter estimator for estimating a frequency error based on the phase parameter, and
- an automatic frequency tracker and controller (AFTC) coupled to the parameter and frequency error estimators for generating a control quantity to adjust the frequency reference, the control quantity being based on the control value, the estimated magnitude parameter and the estimated frequency error.
Dependencies are inferred from the claim text.