Skyworks Solutions, Inc.

Lg Electronics Inc.

Conexant Systems, Inc.

Intel Corporation

Mediatek Corporation

Jaleh Komaili

David Steven Ripley

Yongbing Wan

Masoud Kahrizi

John E Vasa

Thomas Obkircher

Dmitriy Rozenblit

Rajasekhar Pullela

Ricke Waylan Clark

Chris Levesque

William John Domino

Morten Damgaard

Shahrzad Tadjpour

David O Anderton

Jason D Millard

Earl Clyde Cox

Darioush Agahi

Earl C Cox

Scott Walley

Apparatus and methods for transmit power control in wireless communication systems are provided. In one aspect, a wireless communication system includes a transmit chain that generates a transmit signal based on a data signal having a time-varying signal envelope, a power amplifier that amplifies the transmit signal, and a transmit chain controller that generates a first power control signal and a second power control signal that control an adjustable power level of the transmit chain. The transmit chain controller includes an error extractor that generates an error signal based on comparing an output signal power of the power amplifier to the time-varying signal envelope. The transmit chain controller further includes a control signal generator that generates the first power control signal and an adjustment signal based on estimating the error signal, and that generates the second power control signal based on the error signal and the adjustment signal.

Apparatus and methods for transmit power control in wireless communication systems

Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a wireless communication device includes a transmit chain that receives a digital in-phase (I) signal and a digital quadrature-phase (Q) signal and that generates a transmit signal. The wireless communication device further includes a power amplifier that amplifies the transmit signal, and a transmit chain controller including a reference generator that combines the digital I signal and the digital Q signal and generates a reference signal corresponding to an instantaneous value of an envelope of the combined signal. The transmit chain controller further includes an error extractor that generates an error signal based on the reference signal and an output power of the power amplifier, and a control signal generator that uses the error signal to generate one or more power control signals for controlling an adjustable power level of the transmit chain.

Apparatus and methods for controlling transmit power of a wireless communication system

A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Circuits, systems, and methods for managing automatic gain control in quadrature signal paths of a receiver

Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a method for accurately controlling an adjustable power level of a data signal in a transmit chain of a transmitter is provided. The method includes adjusting a controllable gain level of a digital-to-analog converter based on a desired peak-to-average ratio of a transmit signal envelope, adjusting a digitally controlled discrete gain-step amplifier, the amount of gain per step based on an initial estimate of the transmitter gain and a target power, applying a factor to a gain adjuster responsive to the gain step change in the transmit chain, and repeating the adjusting and applying steps until a feedback signal level exceeds a reference signal level.

Apparatus and methods for power control in mobile communication devices

A transmitter adjusts a transmitted power level by modifying a control input of a variable gain amplifier. A power amplifier control system includes an envelope extractor, an error extractor, and a feed-forward multiplier. The envelope extractor receives data signal inputs and computes the envelope of the combined signal. The error extractor generates an error signal as a function of the combined signal and the output power generated by the power amplifier. The feed-forward multiplier generates a modified error signal that is responsive to a function of the gain in a feedback path. A corresponding method for controlling a power level is also disclosed. In some embodiments, a transmit chain with a power control loop is used to adjust the transmit signal power applied at an input of a variable gain amplifier. A corresponding method for adjusting the transmit signal power level is also included.

Systems and methods for power control in a multiple standard mobile transmitter

A transmit signal second-order inter-modulation (IM2) canceller for a portable handset using a full duplex mode of operation (e.g., WCDMA) is used to controllably reduce IM2 introduced by a transmit signal that appears in a received signal in a receive channel of the portable handset. The transmit signal IM2 canceller includes a delay estimator and a digital signal adjuster. The delay estimator receives a first input from a receive channel and a second input from a transmit channel. The delay estimator generates an estimate of the IM2 that the transmit channel introduces in the receive channel. The digital signal adjuster removes the estimate of the IM2 before forwarding a modified receive channel signal to a baseband subsystem of the portable handset.

LMS adaptive filter for digital cancellation of second order inter-modulation due to transmitter leakage

A controller and a circuit work together to enable a selective and dynamic adjustment to correct phase and gain imbalances in quadrature signal paths of a receiver. Under select conditions, it has been determined that statistical estimates of gain and phase imbalance can be applied to adjust signals in the quadrature signal paths of a receiver. The controller validates the select conditions before updating the estimate of the gain imbalance and the estimate of the phase imbalance. The controller directs a compensator under select operating conditions such that validated dynamic estimates of the gain and phase imbalance or calibration data is applied to the quadrature signal paths. The controller disables the compensator and enables an estimator and a calculator when estimates are unavailable for the present operating conditions.

Circuit, controller and methods for dynamic estimation and cancellation of phase and gain imbalances in quadrature signal paths of a receiver

The present invention includes a time-division-multiple-access (TDMA) communication system having a base station and at least one mobile station, each transmitting and receiving an analog radio-frequency signal carrying digitally coded speech. The speech is encoded using a vocoder which samples a voice signal at variable encoding rates. During periods when the radio-frequency channel is experiencing high levels of channel interference, the encoded voice channel having a lower encoding rate is chosen. This low-rate encoded voice is combined with the high degree of channel coding necessary to ensure reliable transmission. When the radio-frequency channel is experiencing low levels of channel interference, less channel coding is necessary and the vocoder having a higher encoding rate is used. The high-rate encoded voice is combined with the lower degree of channel coding necessary to ensure reliable transmission. The appropriate levels of channel coding necessary for reliable transmission are determined by various channel metrics, such as frame erase rate and bit error rate. The determination of the appropriate vocoder rate and level of channel coding for both the uplink and downlink may be determined centrally at the base station, with the vocoder rate and level of channel coding for the uplink being relayed to the mobile station. Alternatively, the appropriate vocoder rate and level of channel coding for the downlink may be determined by the mobile station, and the appropriate vocoder rate and level of channel coding for the uplink may be determined by the base station.

Rate adaptation for use in adaptive multi-rate vocoder

System and method for adaptive multi-rate (AMR) vocoder rate adaptation

A low-noise switching voltage regulator for supplying a voltage to a radio frequency (RF) power amplifier is disclosed. In one embodiment, the invention can be conceptualized as a power amplifier supply circuit, comprising a pair of oppositely polarized semiconductor switches, and a data formatter configured to supply a data stream having a voltage transition on at least every other bit to each of the pair of oppositely polarized semiconductor switches.

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Irvine, CA, United States of America

Jaleh Komaili