Qualcomm Incorporated

Hakan Inanoglu

Steven J Howard

James Arthur Proctor, Jr

Kenneth Marvin Gainey

Leon Metreaud

Mark S Wallace

Xiangdong Zhang

Gwendolyn Denise Barriac

John Wendell Ketchum

Dhananjay Ashok Gore

Jay Rodney Walton

Michael Mao Wang

Michael Lee McCloud

Tao Tian

Francesco Gatta

Adrianus Van Bezooijen

Christos Komninakis

Ryan Scott Castro Spring

Erwin Spits

Antonino Scuderi

Robert Wilson

Chirag Sthalekar

Jiri Stulemeijer

Aspects of the present disclosure provide signal amplification. An example method generally includes amplifying a version of a first input signal with a power amplifier in a first state where a bias voltage of the power amplifier is set to a first voltage based on a first tracking mode; obtaining a first output signal of the power amplifier in a second state where the bias voltage is set to a second voltage less than the first voltage; determining a predistortion associated with the power amplifier based at least in part on the obtained first output signal; applying the predistortion to the first input signal; and amplifying a version of the predistorted first input signal with the power amplifier in a third state where the bias voltage is set to a third voltage based on a second tracking mode, wherein the third voltage is less than the first voltage.

Signal amplification circuitry

A wireless communication device is provided with an in-device capability of characterizing the coupling between a pair of antennas. The wireless communication device determines the coupling through an operating gain measurement and through calibration gain measurements obtained through test ports.

In-device characterization of antenna coupling

An in-situ delay measurement is performed for an envelope-tracking power amplifier of an RF input signal. Because the delay measurement is in-situ, the delay measurement avoids the necessity to down convert and digitize a version of an RF output signal from the envelope-tracking power amplifier.

In-situ measurement of the delay between the envelope and the RF signal in envelope-tracking systems

An echo cancellation wireless repeater with first and second antenna arrays having vertical and horizontal feed antenna elements selects a combination of antenna elements for reception and transmission to reduce interference and improve the quality of signal reception. In one embodiment, the antenna elements are switchably connected to transceiver circuits and a combination of antenna elements is selected based on the best desired performance result. In another embodiment, the antenna elements are each connected to its own transceiver circuit and the echo cancellation repeater performs beamforming in baseband to select a combination of antenna elements.

Method in a wireless repeater employing an antenna array including vertical and horizontal feeds for interference reduction

A wireless repeater with an antenna array determines the antenna weights to modify the spatial selectivity of the antenna array to reduce interference and improve the quality of signal reception. The antenna weights are determined using an error minimizing algorithm to minimize the error between a desired receive signal and a reference signal or an adaptive metric optimization algorithm to calculate adaptively antenna weights to minimize the signal-to-noise ratio of a desired receive signal.

Method in a wireless repeater employing an antenna array for interference reduction

A wireless repeater having a receiving antenna for receiving an input signal and a transmitting antenna for transmitting an amplified signal includes first and second front-end circuits and a repeater baseband block coupled between the first and second front-end circuits. The repeater baseband block includes a channel estimation block, an echo canceller implementing time domain echo cancellation, a variable gain stage controlled by a gain control block implementing digital gain control, a first variable delay element introducing a first delay before or after the echo canceller, a second variable delay element introducing a second delay to the output signal. The delayed output signal is coupled to the channel estimation block as a reference signal for estimating the feedback channel, to the echo canceller as a reference signal for estimating the feedback signal, and to the gain control block for monitoring the stability of the repeater.

Wideband echo cancellation in a repeater

Certain aspects and embodiments provide for accurate measurement and estimation of imbalances between in-phase (I) and quadrature (Q) components of a complex baseband signal. The accuracy of I/Q phase imbalance estimates may be enhanced by conducting them on a transmitter and a receiver that are connected via a local, loopback connection and by removing cross-spectrum interference in transferred packets. Once these accurate I/Q phase imbalances are determined, they may be used to adjust a signal processed by the transmitter or the receiver to increase the performance and data throughput of communications using the signal.

I/Q imbalance estimation and correction in a communication system

Techniques for calibrating the transmit and receive chains at a wireless entity are described. For a pre-calibration, N first overall gains for a receiver unit and N transmitter units in the transmit chain are obtained, where N&#x3e;1. Each first overall gain is for a combined response for the receiver unit and the associated transmitter unit. N second overall gains for a transmitter unit and N receiver units in the receive chain are also obtained. Each second overall gain is for a combined response for the transmitter unit and the associated receiver unit. The gain of each transmitter unit and the gain of each receiver unit are determined based on the first and second overall gains. At least one correction matrix is then derived based on the gains of the transmitter and receiver units and is used to account for the responses of these units.

Calibration of transmit and receive chains in a MIMO communication system

Techniques for decomposing matrices using Jacobi rotation are described. Multiple iterations of Jacobi rotation are performed on a first matrix of complex values with multiple Jacobi rotation matrices of complex values to zero out the off-diagonal elements in the first matrix. For each iteration, a submatrix may be formed based on the first matrix and decomposed to obtain eigenvectors for the submatrix, and a Jacobi rotation matrix may be formed with the eigenvectors and used to update the first matrix. A second matrix of complex values, which contains orthogonal vectors, is derived based on the Jacobi rotation matrices. For eigenvalue decomposition, a third matrix of eigenvalues may be derived based on the Jacobi rotation matrices. For singular value decomposition, a fourth matrix with left singular vectors and a matrix of singular values may be derived based on the Jacobi rotation matrices.

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Acton, MA, United States of America

Hakan Inanoglu