Broadcom Corporation

Avago Technologies International Sales Pte. Limited

Colin Fraser

Arya Behzad

Mark Gonikberg

George Varghese

Luis Javier Gutierrez

Dengwei Fu

Amir Dov Eliaz

Ali Afsahi

Daniel Stopler

Konrad W Kratochwil

Navid Lashkarian

Utku Seckin

Sandeep Shenoy

High peak-to-average ratio of OFDM signals requires large back-off from an RF power amplifier's saturation power. A spectral shaper device therefore increases the output power and efficiency of the power amplifier. The shaper device performs linearization through digital predistortion, based on an out-of-band regrowth limit, as well as the EVM requirement for a particular data rate. The shaper can distribute the error energy, precisely, over frequencies such that each of the inband and out-of-band requirements is independently and individually met. The shaper distributes error energy to frequency regions in the spectrum to the maximally allowed by the standards and regulations, while not increasing the total error. The error energy is kept to the minimum where it is crucial in meeting EVM requirements. In this way, the shaper maximizes the allowable output power of the nonlinear power amplifier.

Time domain transmitter signal shaping

Aspects of a method and system for estimating and compensating for non-linear distortion in a transmitter using calibration are presented. Aspects of the system may include one more circuits that may enable estimation, within a single IC device, of distortion in output signals generated by a transmitter circuit. The circuitry may enable compensation of the estimated distortion by predistorting subsequent input signals. The transmitter circuit may generate subsequent output signals based on the predistorted subsequent input signals.

Method and system for estimating and compensating non-linear distortion in a transmitter using calibration

Communication processing paths include distortions, such as DC offset in the baseband analog path, local oscillator feed-through distortion, and nonlinearity of gm's and power amplifiers which are calibrated for, separately or in combination. The cascaded DC offset and nonlinear distortions are modeled separately or in combination using even-and-odd order polynomials. A loopback path from the output of one or more distortion causing devices passes through a measurement and calculation module. The calculation module calculates predistortion polynomial's coefficients which will be stored in a look-up table to be used by a baseband predistorter to calibrate the path. The look-up table is stored locally or remotely.

Calibration of communication processing path

A wireless device includes an antenna, Radio Frequency (RF) circuitry, and baseband processing circuitry. The baseband processing circuitry couples to the RF circuitry and is operable to determine operational calibrations settings that may include pre-distortion characteristics and RF signal path settings, both of which are determined via calibration operations. The calibration operations are initiated when an operational value of the wireless device compares unfavorably to at least one operational threshold. Monitoring circuitry coupled to the RF circuitry and to the baseband processing circuitry monitors operational characteristics of the RF circuitry. Calibration operations may be initiated based upon RF circuitry temperature, supply voltage, PA current, PA gain input level/average, among other triggers.

Gain index based radio calibration

Transmitter calibration of a wireless device is initiated based upon an operational value of the wireless device. The calibration operations are performed over a plurality of calibration time periods, each calibration time period divided into a plurality of first interval portions interspersed with a plurality of second interval portions, for each calibration time period of the plurality of calibration time periods, respective calibration settings are applied. During the first interval portions substantially fixed first current input is applied to at least one gain adjustable element of the RF circuitry. During the second interval portions, varying current input is applied to the at least one gain adjustable element of the RF circuitry. Output levels of the RF circuitry are measured over the calibration time period. Operational calibration settings for the baseband processing circuitry and analog signal path components of the transmitter are selected based upon the calibration operations.

Pulsed interval radio calibration

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Mountain View, CA, United States of America

Colin Fraser