Freescale Semiconductor,inc.

Intel Corporation

George Norris

Joseph Staudinger

Patrick Joseph Pratt

Claudio Gustavo Rey

David A Newman

Benjamin Gilsdorf

Jau Horng Chen

Daniel B Schwartz

Kevin B Traylor

Bing Xu

David S Peckham

David B Harnishfeger

Mark Alan Kirschenmann

Jeffrey D Ganger

Richard B Meador

Gary W Sadowniczak

Richard E Sherman

Jau-Horng Chen

Aspects of an envelope tracking operation are described. In some aspects, as part of the envelope tracking operation, a device determines a change in a first set of power amplifier (PA) operating conditions, corresponding to a first look up table (LUT), the first LUT defined by a first LUT equation and a maximum supply voltage value. In some aspects, the device autonomously generates a second LUT equation to define a second LUT, having a second set of corresponding PA operating conditions. In some aspects, the device selects values from the first LUT equation, estimates a slope of the second LUT equation, determines an intercept with a maximum power value, and adjusts a supply voltage input for the PA to a supply voltage according to the maximum power value.

Autonomous power reduction

In accordance with some embodiments of the present disclosure, a method may include determining a range of frequencies allocated to resource blocks to be transmitted during a subsequent sub-frame slot or sounding reference symbol sub-slot. The method may also include determining an approximate center frequency of the range of frequencies. The method may additionally include modulating resource blocks of the sub-frame or sounding reference symbol sub-slot at the approximate center frequency. The method may further include transmitting the modulated resource blocks at the approximate center frequency.

System and method for frequency-agile transmission in a wireless communication device

Systems and techniques are described for applying a polar bias modulation having a phase component and an amplitude component to a signal amplified by a power amplifier. The power amplifier (PA) has a plurality of amplifier gain stages and is configured to amplify an input to create an amplifier output signal. The input to the power amplitude is phase modulated based upon the phase component of the polar bias modulation, but need not be amplitude modulated. Amplitude modulation is provided by logic that includes a detector configured to receive an indication of the amplifier output as a feedback signal, a control module configured to generate a control signal based upon both the feedback signal and the amplitude component of the polar bias modulation, and a bias circuit configured to adjust a bias signal associated with at least one of the plurality of amplifier gain stages in response to the control signal. Such a modulation scheme may be readily applied in enhanced data rate for global service mode (GSM) evolution (EDGE) applications, as well as in other environments that make use of polar modulation.

System and method for polar modulation using power amplifier bias control

A wireless communication unit comprising a transmitter having a power amplifier, a controller logic module arranged to control a power control value of the power amplifier and a closed loop control system operably coupled to the power amplifier and arranged to monitor a level of peak PA compression, wherein in response to the identified level of peak PA compression the controller logic module is arranged to automatically adjust a power amplifier power control value of the PA to obtain a predetermined level of peak PA compression.

Wireless communication unit, integrated circuit and method of power control of a power amplifier therefor

A wireless communication unit comprises a transmitter having a forward path comprising a power amplifier, PA, and a feedback path arranged to feed back a portion of a signal output from the PA to a point in the forward path prior to the PA. The forward path and feedback path form a constant gain tracking (CGT) loop. The feedback path comprises an adaptive predistortion logic module located outside of the CGT loop and arranged to form an APD loop with the forward path and feedback path. The CGT loop comprises a controller logic module arranged to determine a gain offset of a signal routed through the forward path and feedback path and in response thereto set a drive level of the PA.

Embodiments include methods and apparatus for detecting a phase angle between an incident signal and a reflected signal. The apparatus comprises a plurality of phase shifters and additional circuitry. The plurality of phase shifters is adapted to apply first phase shifts to a representation of the incident signal and to apply second phase shifts to a representation of the reflected signal. The additional circuitry, which is operatively coupled to the plurality of phase shifters, is adapted to produce a first indication of a location of a relative phase difference between the incident signal and the reflected signal within a first region of a first reference circle, and to produce a second indication of the location of the relative phase difference within a second region of a second reference circle, wherein the second reference circle is rotated with respect to the first reference circle.

Incident and reflected signal phase difference detection

In an embodiment, a digital pre-distortion apparatus processes an input signal to produce a pre-distorted signal, and processes the pre-distorted signal to produce a feedback signal. The apparatus also rotates an adjustment gain by a gain rotation angle to produce a rotated adjustment gain, where the gain rotation angle is based on a phase difference between the input signal and the feedback signal. The apparatus also applies the rotated adjustment gain to the feedback signal, which may result in rotation of the feedback signal into a target phase region.

Systems, apparatus, and methods for performing digital pre-distortion with feedback signal adjustment

A system (, FIG.) performs digital pre-distortion using gain values stored in a lookup table (). A method for performing digital pre-distortion includes identifying (, FIG.) a lookup table entry, based on input data, and updating the lookup table entry by writing an updated gain value into the lookup table entry. In an embodiment, update tracking information corresponding to the lookup table entry may be updated () to indicate that the lookup table entry has been updated. Another embodiment includes identifying (, FIG.) consecutive lookup table entries based on input data, determining () whether the consecutive lookup table entries have been previously updated, and performing () a weighted interpolation process to produce an output gain value. A previous gain value (, FIG.) is used in the weighted interpolation process when at least one of the consecutive lookup table entries has not been updated.

Systems, apparatus and method for performing digital pre-distortion based on lookup table gain values

Embodiments include methods, apparatus, and electronic systems adapted to perform adaptive pre-distortion. Embodiments include combining an input sample with a gain value to generate a pre-distorted data sample, where the gain value is a function of at least one gain entry stored within a gain lookup table. An amplified analog signal is generated from the pre-distorted data sample, and a feedback sample is also generated, which corresponds to an antenna output signal. The antenna output signal includes the amplified analog signal. A difference indicator is generated to reflect a difference between the input sample and the feedback sample, and at least one updated gain value is generated based on a comparison between the difference indicator and at least one previous difference indicator. At least one gain entry within the gain lookup table is updated with the at least one updated gain value.

Adaptive pre-distortion with interference detection and mitigation

A balanced power amplifier that is insensitive to load line variations is provided. The balanced power amplifier is suitable for use in wireless transmitter applications, such as cellular telephones, mobile computing devices, and portable communication devices. An embodiment of such a balanced power amplifier includes an input coupler, first and second amplifier devices, and a level adjustment component. The input coupler generates a first signal component and a second signal component from an input signal, where the first signal component and the second signal component are out of phase relative to one another. The first amplifier device generates a first output signal that is influenced by the first signal component, and the second amplifier device generates a second output signal that is influenced by the second signal component. The level adjustment component is coupled between the input coupler device and the input of the first amplifier device. The level adjustment component performs signal level tuning on its input signal. The signal level tuning is adaptively performed in response to the impedance characteristics of the load being driven by the balanced power amplifier.

Load insensitive balanced power amplifier and related operating method

A radio frequency ('RF') power amplifier circuit as described herein is configured to detect and measure an output load mismatch and to adjust the operating characteristics of the RF power amplifier to reduce output signal distortion. The circuit includes a directional RF signal coupler that obtains a coupled reflected RF signal that is indicative of the output load mismatch. The coupled reflected RF signal is processed to generate one or more bias control signals for the RF power amplifier. In operation, a mismatch condition will result in a measurable coupled reflected RF signal and a corresponding reduction in output power from the RF power amplifier. Ultimately, the output power control mechanism strives to maintain the RF power amplifier within a linear operating range.

Power amplifier with VSWR detection and correction feature

A soft saturation detection circuit for a radio frequency ('RF') power amplifier is configured to detect the onset of soft saturation in an unambiguous and accurate manner. The circuit compares the time derivative of a voltage signal indicative of the RF output power to the time derivative of a control voltage signal for the RF power amplifier. The circuit also employs a gating mechanism that ensures that a soft saturation indication signal is generated under appropriate operating conditions.

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Gilbert, AZ, United States of America

George Norris