Motorola Corporation

Freescale Semiconductor,inc.

Christopher P Thron

T Keith Blankenship

Michael B Thomas

Chengke Sheng

David J Anderson

George Francis Opas

Andrew Merritt Khan

Curtis M Williams

Dipesh Koirala

A technique of operating a wireless communication device includes receiving, at a first wireless communication device, respective signals transmitted from multiple second wireless communication devices. Respective channel matrix blocks for each block of the received respective signals are then generated. Finally, respective channel equalizer matrix blocks for each of the respective channel matrix blocks are generated. At least one of the respective channel equalizer matrix blocks is generated without performing a matrix inversion operation on an associated one of the respective channel matrix blocks.

Techniques for frequency-domain joint detection in wireless communication systems

A method for efficiently calculating signal thresholds for use in signal processing is described. The method computes and stores a cumulative histogram and a weighted cumulative histogram. The method then provides a first estimate for a threshold based on a single ratio. The method next performs an iterative computation to get to the ultimate threshold result. Method iterations only require multiplication and addition operations on the stored values making the method well suited for implementation in fixed-point digital signal processors.

Efficient fixed-point real-time thresholding for signal processing

A method and apparatus for predistortion training in an amplifier using predistortion is provided herein. Predistortion takes place by collecting a series of envelope errors and averaging the envelope errors for various amplitude regions. LUT values are modified based on a curve-fit to the average amplitude values for each amplitude region. By utilizing a curve-fitting technique, the pitfalls of modifying individual LUT coefficients is avoided. Particularly, because the errors are collected in relatively broad regions and then averaged, the importance of exact correlation between a measured error and a specific LUT entry is significantly lessened.

Method and apparatus for predistortion training in an amplifier utilizing predistortion

A method of channel estimation in a Code Division Multiple Access (CDMA) transmission system that incorporates Pilot Symbol Assisted Modulation (PSAM) using an iterative coherent detection method to estimate the phase and frequency of the received pilot symbols. Arctangent calculations are used to estimate phase and frequency. An iterative least squares linearization identifies and corrects values of the arctangent associated with an incorrect 2&#x3c0; alias, which arise due to the multiple-valued nature of the arctangent function. An alternative non-iterative least squares linearization also corrects the arctangent values, based on a calculation involving stored values of the pilot symbols.

Method and apparatus for coherent detection in a telecommunications system

A method for linearizing an amplifier to produce an amplified output signal from a set of carrier frequencies is disclosed in which a set of digital baseband signals corresponding to the set of carrier frequencies are combined to produce an extended digital baseband signal. Look-up values are then derived from the power values of the extended digital baseband signal and applied to a look-up table to obtain predistortion values. One or more predistorted signals are then produced by complex mixing the predistortion values with one of the set of extended digital baseband signals. The predistorted signal(s) are then amplified to produced an output signal which is linearly related to the set of digital baseband signals. In one embodiment, linearly combining the set of digital baseband signals includes complex mixing individual digital baseband signals of the set of digital baseband signals with trigonometric signals to produce complex mixed signals and adding the complex mixed signals to produce the extended digital baseband signal. Producing one or more predistorted signals may include upconverting the predistorted signals synchronously when the predistorted signals are a complex mixing of the predistortion values and the set of digital baseband signals. In one embodiment, the look-up table is a function of pre-measured calibration data.

Extended base band multicarrier system

A method for predistorting a digital signal prior to amplification is disclosed in which a look-up table is computed using power values of digital input signal samples as look-up values. The look-up table is preferably a function of pre-measured calibration data. The look-up table is applied to digital input signals for producing the predistorted signal. Computing the look-up table may include determining a set of input power values, obtaining the pre-measured calibration data including an output power data value and phase data value of the amplifier corresponding to each of the input power values, and deriving a set of calibration power values using the output power data values. The calibration power values and the input power values are then used to derive amplitude predistortion calibration values while the phase data values are used to determine phase predistortion calibration values. The calibration power values and corresponding amplitude predistortion calibration values are interpolated to provide amplitude predistortion values while the calibration power values and corresponding phase predistortion calibration values are interpolated to provide phase predistortion values. The look-up table is computed from the amplitude predistortion values and the phase predistortion values.

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Austin, TX, United States of America

Christopher P Thron