Abstract: This disclosure provides systems, methods, and devices for wireless communications that support multiple antenna operation. In a first aspect, an apparatus for wireless communications includes an amplifier module comprising a first input node, a second input node, a first output node, a second output node, and a third output node, with the amplifier comprising a first processing path configured to couple the first input node to the first output node; and a second processing path configured to couple the second input node to the second output node in a first mode and to couple the second input node to the third output node in a second mode. Other aspects and features are also claimed and described.

Abstract: Certain aspects of the present disclosure generally relate to electronic components and, more particularly, to radio frequency front-end (RFFE) circuitry. One example apparatus may include a controller configured to: determine a first calibration point and a second calibration point for an amplifier, wherein the first calibration point is associated with a first supply voltage for the amplifier, and wherein the second calibration point is associated with a second supply voltage for the amplifier; and determine an operating point for the amplifier by interpolating based on the first calibration point and the second calibration point, the operating point being associated with a third supply voltage. The apparatus may also include an interface configured to control a power supply to provide the third supply voltage associated with the operating point for the amplifier.

Abstract: A transmitter is provided that determines a compression of an envelope-tracking amplifier using a function of the amplifier's power supply voltage, input signal voltage, and output signal voltage. An input signal adjustment circuit adjusts the input signal to the envelope-tracking amplifier responsive to a difference between the compression and a desired fixed value for the compression.

Abstract: Certain aspects of the present disclosure provide techniques for multi-stage impedance tuning for a radio frequency (RF) transmitter. An example apparatus includes RF circuitry comprising an amplifier, an impedance tuning circuit coupled to an output of the amplifier, and an antenna tuner coupled between an antenna feed and an output of the impedance tuning circuit. The apparatus further includes one or more memories and one or more processors coupled to the one or more memories. The one or more processors are configured to cause the apparatus to configure at least one parameter of the impedance tuning circuit or the amplifier based at least in part on at least one load characteristic at the antenna feed; and communicate one or more signals via the RF circuitry while the at least one parameter is configured based at least in part on the at least one load characteristic at the antenna feed.

Abstract: 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.

Abstract: This disclosure provides systems, methods, and devices for wireless communications that support multiple antenna operation. In a first aspect, an apparatus for wireless communications includes an amplifier module comprising a first input node, a second input node, a first output node, a second output node, and a third output node, with the amplifier comprising a first processing path configured to couple the first input node to the first output node; and a second processing path configured to couple the second input node to the second output node in a first mode and to couple the second input node to the third output node in a second mode. Other aspects and features are also claimed and described.

Abstract: Certain aspects of the present disclosure generally relate to electronic components and, more particularly, to radio frequency front-end (RFFE) circuitry. One example apparatus may include a controller configured to: determine a first calibration point and a second calibration point for an amplifier, wherein the first calibration point is associated with a first supply voltage for the amplifier, and wherein the second calibration point is associated with a second supply voltage for the amplifier; and determine an operating point for the amplifier by interpolating based on the first calibration point and the second calibration point, the operating point being associated with a third supply voltage. The apparatus may also include an interface configured to control a power supply to provide the third supply voltage associated with the operating point for the amplifier.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Exemplary embodiments are related to a wireless transmitter device. A device may include a power amplifier configured to receive a supply voltage and an input signal. The device may further include switch coupled to the supply voltage and the power amplifier via an inductor and configured to couple the inductor to one of a ground voltage and the supply voltage. The device may also include a prediction engine configured to receive the input signal and convey a signal to the switch to couple the inductor to the ground voltage upon detection of an overshoot event.

Abstract: 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.

Abstract: 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.

Abstract: A method for a self-calibrating reduction in inphase/quadrature imbalance is described. An inphase/quadrature amplitude imbalance is calculated. A correction to the inphase/quadrature amplitude imbalance is applied. An estimated inphase/quadrature phase imbalance is calculated. Calculating an estimated inphase/quadrature phase imbalance includes calculating a loopback phase. A correction to the estimated inphase/quadrature amplitude imbalance is applied.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.