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US 2011/0216851 A1Published application
Robust transmit/feedback alignment
AssigneeTexas Instruments Incorporated
InventorsFernando A. Mujica, Hardik P. Gandhi, Kun Shi
Life of this patent
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Abstract
Performing digital predistortion (DPD) for widely spaced narrowband signals, such as the signal used in multi-carrier GSM, can be very difficult. Here, a system is provided the performs DPD for widely spaced narrowband signals. In particular, this system uses a polynomial curve for values of a cross-correlation function (above a predetermined threshold) to determine a delay estimate, which allows for a more robust and accurate system.
Claims17
An apparatus comprising:
- a digital predistortion (DPD) circuit that receives an input signal and that generates a predistorted signal from the input signal and predistortion coefficients;
- a delay element that receives an amplified signal and that provides a delayed output signal;
- a delay estimator that receives the delayed output signal and the predistorted signal and that generates a delay estimation by determining a peak value from a polynomial curve fit of values from a cross-correlation function of the delayed output signal, wherein the values of the cross-correlation function are greater than a predetermined threshold;
- and
- a DPD adapter that receives the delay estimation and that generates the predistortion coefficients.
2 more elements
A system comprising:
- a transmit path having an amplifier;
- an antenna that is coupled to the transmit path;
- a feedback path that is coupled to the transmit path;
- and
- transmit processing circuitry that is coupled to transmit path and the feedback path, wherein the transmit processing circuitry includes:
- a DPD circuit that receives a input signal and that generates a predistorted signal from the input signal and predistortion coefficients;
- a delay element that receives an amplified signal from the feedback path and that provides a delayed output signal;
- a delay estimator that receives the delayed output signal and the predistorted signal and that generates a delay estimation by determining a peak value from a polynomial curve fit of values from a cross-correlation function of the delayed output signal, wherein the values of the cross-correlation function are greater than a predetermined threshold;
- and
- a DPD adapter that receives the delay estimation and that generates the predistortion coefficients.
7 more elements
An apparatus comprising:
- a transmit processor having a DPD circuit that receives a input signal and that generates a predistorted signal from the input signal and predistortion coefficients;
- and
- a DSP that is coupled to the transmit processor having a computer program product embodied thereon, wherein the computer program product includes:
- computer code for delaying the amplified signal to produce the delayed output signal;
- computer code for generating a delay estimation by determining the peak value from the polynomial curve fit of values from the cross-correlation function of the delayed output signal;
- and
- computer code for generating the predistortion coefficients from the delay estimation.
4 more elements
Dependencies are inferred from the claim text.