Disclosed are digital predistortion implementations, including a method that includes collecting data for a wireless device with a transmit chain that includes at least one power amplifier that produces output with non-linear distortions, the data including data records that each includes input signal data and corresponding output signal data for the transmit chain, and with each record being associated with a set of operating conditions values, and with a variety measure representative of an extent of distinguishability of the record from other data records. The method further includes selecting at least some of the data records according to a variety criterion computed based on the variety measure for each record, computing, based on the selected records, digital predistortion parameters used to control a digital predistorter of the wireless device, and applying the digital predistorter, configured with the computed digital predistortion parameters, to subsequent input signals.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

A circuit in a wireless communications terminal/device and a method is described for reducing an image distortion. By measuring three gain mismatches of I path and Q path of a transceiver, and estimating a value of an IQ mismatch coefficient based on the three gain mismatches; and applying a measurement adjustment to the I path or the Q path based on the value of the IQ mismatch coefficient, the image distortion is reduced.

Circuitry, method and computer program for reducing distortions in a plurality of amplified signals to be radiated by a multiple antenna system. The circuitry comprising: a plurality of inputs for receiving digital signals for a plurality of forward data paths; routing circuitry for routing the digital signals received at the plurality of inputs to pre-distortion logic for applying a pre-distortion function to each of the signals, the pre-distortion logic being operable to forward each of the signals towards a digital to radio frequency converter and subsequent amplifier for amplifying the signals prior to the signals being radiated; one or more feedback paths each comprising processing logic for comparing a feedback signal generated from one of the amplified signals with a corresponding signal received at one of the inputs to determine a function to be applied by the pre-distortion logic to the input signal; selecting logic for selecting the input signal to be provided with the feedback.

A power amplifier system includes an input operable to receive an original value that reflects information to be communicated and an address data former operable to generate a digital lookup table key. The power amplifier system also includes a predistortion lookup table coupled to the address data former and a power amplifier having an output and coupled to the predistortion lookup table. The power amplifier system further includes a feedback loop providing a signal associated with the output of the power amplifier to the predistortion lookup table and a switch disposed in the feedback loop and operable to disconnect the predistortion lookup table from the output of the power amplifier.

A method for distortion compensation in a transmission link comprising obtaining information of an amplitude distribution of a signal prior to being transmitted by a transmitter, receiving the transmitted signal at a receiver and determining a received signal amplitude distribution, comparing the received signal amplitude distribution to the amplitude distribution of the signal prior to transmission and using results of the comparison to estimate the AM/AM non-linearity in the transmitter.

A method for determining a noise shaped quantized parameter contributing to generation of an output signal comprises estimating an error within the output signal using a quantization of the parameter and a quantization of a further parameter contributing to generation of the output signal. The quantization of the parameter is used as the noise shaped quantized parameter according to a selection criterion.

A communication system includes a conversion module configured to convert a signal between a radio frequency baseband (RF-BB) and an intermediate frequency (IF). At least one RF front-end module converts the signal between the IF and a radio frequency (RF). The RF front-end module is configured as an RF phased array and includes a coaxial interconnect configured to connect the conversion module with the RF front-end module. The signal is transmitted between the conversion module and the RF-front end module via the coaxial interconnect. At least one RF front-end module includes an active front-end (AFE) configured to allow the signal to be transmitted via the coaxial interconnect while minimizing any deterioration of the signal.

Supporting suppression of distortion caused by a power amplifier, PA, included in a transmitter system configured to perform digital predistortion, DPD, and feedforward, FF, linearization on multiple digital input signals relating to different frequency bands, respectively. The PA is used for power amplification in preparation for transmission by a wireless communication network and is operative with an instantaneous bandwidth, IBW. Information is obtained identifying one or more intermodulation, IM, components outside the frequency bands but within the IBW, and caused by said PA. The identified IM components are selectively processed as part of said DPD to thereby suppress formation of at least some of the identified IM components, and/or as part of the FF linearization by adding reference signals to the FF linearization, which reference signals correspond to at least some of the identified IM components.

There is provided mechanisms for beamformed transmission using a precoder. A method is performed by a radio transceiver device. The radio transceiver device comprises hardware. The hardware impacts transmission of signals from the radio transceiver device. The method comprises acquiring channel conditions of a radio propagation channel between the radio transceiver device and at least one other radio transceiver device. The method comprises determining a precoder, in form of a linear precoding matrix, for beamformed transmission towards the at least one other radio transceiver device. The precoder is determined according to the channel conditions and a model of how the hardware impacts the transmission of signals from the radio transceiver device. The method comprises transmitting, using the precoder, a signal towards the at least one other radio transceiver device.