Abstract: Radio transmitters providing an analog signal with both radio frequency (RF) and baseband frequency information are disclosed herein. In certain embodiments, a transmitter for an RF communication system includes a radio frequency digital-to-analog converter (RFDAC) that outputs the analog signal with two bands of content. In particular, the analog signal includes a first band on content at RF frequency and representing the RF signal for transmission, and a second band of content at baseband frequency and representing baseband information such as the envelope of the RF signal.

Abstract: Methods and apparatuses for controlling a reconfigurable intelligent surface (RIS) to generate one or more modulated symbols may be described herein. The processor may be configured to generate an amplitude of the modulated symbol(s) by activating one or more of the plurality of portions of the RIS. The processor may be configured to generate a phase of modulated symbol(s) by controlling one or more phase shifts applied by one or more activated portions of the RIS. The method may include transmitting the one or more modulated symbols using the RIS. The method may include a RIS-based joint beamforming and/or modulation scheme with low PAPR. The RIS may be divided into one or more portions for attaining various gains. The RIS may be divided into an In-phase and/or Quadrature branches. The method may include an Amplitude-phase shift keying (A-PSK) and/or Quadrature amplitude-phase shift keying (AQ-PSK) joint beamforming and/or modulation scheme(s).

Abstract: The embodiments of the present application relate to the field of communications, and provide a signal distortion pre-correction method, a signal distortion pre-correction device, and a non-volatile storage medium. In the present application, the mutual coupling filtering parameters and the predistortion coefficient candidate set are obtained by training the feedback signal collected by the multi-channel coupling element, so that the mutual coupling filtering processing can be performed on the forward signal of the digital channel according to the obtained mutual coupling filtering parameter, to make the target predistortion coefficient selected in the predistortion coefficient candidate set according to the forward signal after mutual coupling filtering and the forward signal of the digital channel to be processed to be the predistortion coefficient considering the mutual coupling factor of the digital channel.

Abstract: Systems and methods are provided for the denoising of images in the presence of broadband noise based on the detection and/or estimation of in-band noise. According to various example embodiments, an estimate of broadband noise that lies within the imaging band is made by detecting or characterizing the out-of-band noise that lies outside of the imaging band. This estimated in-band noise may be employed for denoise the detected imaging waveform. According to other example embodiments, a reference receive circuit that is sensitive to noise within the imaging band, but is isolated from the imaging energy, may be employed to detect and/or characterize the noise within the imaging band. The estimated reference noise may be employed to denoise the detected in-band imaging waveform.

Abstract: Loss caused by wiring is reduced. A radio frequency module includes a mounting board, a low-noise amplifier, and an input matching circuit. The mounting board has a first principal surface and a second principal surface. The first principal surface and the second principal surface are on opposite sides of the mounting board. The low-noise amplifier amplifies a reception signal (first reception signal). The input matching circuit includes an inductor. The inductor is connected to the input side of the low-noise amplifier. The inductor is arranged on the first principal surface side of the mounting board. The low-noise amplifier is arranged on the second principal surface side of the mounting board. In a plan view seen from a thickness direction of the mounting board, at least part of the inductor overlaps with at least part of the low-noise amplifier.

Abstract: A current mode end-to-end signal path includes, a digital to analog converter (DAC), operating in current mode and an upconverting mixer, operating in current mode and operatively coupled to the DAC, wherein analog inputs and analog outputs of the DAC and the upconverting mixer are represented as currents, and the DAC generates a baseband signal.

Abstract: A radio communication device includes: a plurality of antenna elements; a phase shifter that applies weights for each of the antenna elements respectively to first-band data and second-band data of different frequency bands to form beams corresponding to the first-band data and the second-band data; a power amplifier that is arranged for each of the antenna elements; and a processor configured to compensate for non-linear distortion.

Abstract: Multi-level envelope tracking systems with separate DC and AC paths are provided. In certain embodiments, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a multi-level supply (MLS) DC-to-DC converter that outputs multiple regulated voltages, an MLS modulator that controls selection of the regulated voltages over time based on an envelope signal corresponding to an envelope of a radio frequency (RF) signal amplified by the power amplifier, an AC path filter coupled between an output of the MLS modulator and the power amplifier supply voltage, and a DC path filter coupled between a DC voltage and the power amplifier supply voltage.

Abstract: Methods, systems, and devices for wireless communications are described. For example, a transmitting wireless device, such as a user equipment or a base station, may apply a first set of digital pre-distortion (DPD) coefficients to a plurality of antenna elements to form a first transmit beam. The wireless device may determine to switch from using the first transmit beam to using a second transmit beam that is different from the first transmit beam and may apply a second set of DPD coefficients to the plurality of antenna elements to form the second transmit beam, where the second set of DPD coefficients is different from the first set of DPD coefficients. The wireless device may transmit signaling using the second transmit beam based at least in part on applying the second set of DPD coefficients.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine that the UE is connected to a wireless network on a first carrier frequency in a first frequency range that is associated with a lower data rate than a second carrier frequency in a second frequency range. In some aspects, the first frequency range may be associated with a first version of a radio access technology (RAT) and the second frequency range may be associated with a second version of the RAT. The UE may determine a bandwidth metric associated with the first carrier frequency in the first frequency range. The UE may display a first visual indicator associated with the first version of the RAT or a second visual indicator associated with the second version of the RAT based on the bandwidth metric. Numerous other aspects are described.

Abstract: The present application provides a signal compensation method and a signal compensation device; in which, a pre-equalization processing is performed respectively on a plurality of bits corresponding to each modulation symbol in a bit sequence to be modulated, and results of the pre-equalization processing are simply added and then subjected to a nonlinear predistortion processing.

Abstract: A signal transmitter is provided. The signal transmitter includes a signal splitting module, including M output interfaces, where the signal splitting module is configured to split a signal into N sub-signals, and output the N sub-signals through N of the M output interfaces, where M and N are integers, M?2, N?1, and M?N, an integrated array traveling-wave tube amplifier, including M radio frequency channels, where the M channels one-to-one correspond to the M output interfaces, each channel is configured to perform power amplification on a sub-signal that is output from a corresponding output interface, and each channel is openable and closeable, a power supply module, configured to supply power to the integrated array traveling-wave tube amplifier, and at least one transmit antenna, configured to send a signal obtained through power amplification.

Abstract: Disclosed are systems, devices, modules, methods, and other implementations, including a method for digital predistortion that includes receiving, by a digital predistorter, a first signal that depends on amplitude variations based on an input signal, u, with the variations of the first signal corresponding to time variations in non-linear characteristics of a transmit chain that includes a power amplifier. The method further includes receiving, by the digital predistorter, the input signal u, generating, by the digital predistorter, based at least in part on signals comprising the input signal u and the first signal, a digitally predistorted signal v to mitigate the non-linear behavior of the transmit chain, and providing the predistorted signal v to the transmit chain.

Abstract: A voltage regulator includes a slew-up circuit, a slew-down circuit and a transient response control circuit, and provides a regulated output voltage. The slew-up circuit is designed to couple a first node of the voltage regulator to a first constant reference potential upon occurrence of a first condition of the regulated output voltage. The slew-down circuit is designed to couple the first node to a second constant reference potential upon occurrence of a second condition of the regulated output voltage. The transient response control circuit is designed to disable the slew-up circuit and the slew-down circuit upon the rate of change of the regulated output voltage exceeding a predetermined rate. The first node is one of an output node and an output steering node of the voltage regulator. Transient response of the voltage regulator is accordingly improved.

Abstract: Systems and methods are provided for the denoising of images in the presence of broadband noise based on the detection and/or estimation of in-band noise. According to various example embodiments, an estimate of broadband noise that lies within the imaging band is made by detecting or characterizing the out-of-band noise that lies outside of the imaging band. This estimated in-band noise may be employed for denoise the detected imaging waveform. According to other example embodiments, a reference receive circuit that is sensitive to noise within the imaging band, but is isolated from the imaging energy, may be employed to detect and/or characterize the noise within the imaging band. The estimated reference noise may be employed to denoise the detected in-band imaging waveform.

Abstract: A device configured to perform wireless communication includes: a pre-distortion circuit configured to generate a pre-distorted input signal by performing pre-distortion on an input signal based on a parameter set comprising a plurality of coefficients; a power amplifier configured to generate an output signal by amplifying an RF signal based on the pre-distorted input signal; and a parameter obtaining circuit configured to obtain second memory polynomial modeling information corresponding to an operating frequency band based on first memory polynomial modeling information corresponding to each of a plurality of frequency sections and obtain a parameter set according to an indirect learning structure by using the second memory polynomial modeling information.

Abstract: A method of a user equipment (UE) in a wireless communication system is provided, the method comprises receiving, from a base station (BS), configuration information including a number of total beam quantities (N) and a number of selected beam quantities (L), wherein L?N; calculating an index indicating L selected beam quantities out of N total beam quantities based on the configuration information and a predefined mapping table including combinatorial binomial coefficient values, C ? ( x , y ) = ( x y ) (i.e., x choose y); and transmitting, to the BS, the index indicating the L selected beam quantities.

Abstract: A digital signal process unit includes a first cancel signal generation unit and a second cancel signal generation unit. The first cancel signal generation unit generates, as a first cancel signal component, a cancel signal component corresponding to an image signal included in an analog signal output from a mixer. The second cancel signal generation unit generates, as a second cancel signal component, a cancel signal component corresponding to a leakage signal generated between an input and output of the mixer. The digital signal process unit includes subtractors for subtracting the first cancel signal component and the second cancel signal component from a signal component corresponding to a frequency band divided from an input signal to obtain a digital signal.

Abstract: An improved amplification of multiband signals for an uplink, in particular a satellite uplink is provided. For this purpose, multiple signals for separate frequency bands may be provided to a number of two or more uplink converters. The output of each uplink converter is amplified by a separate amplifier and the separately amplified signals are combined to obtain an amplified multiband uplink signal. In particular a waveguide combiner may be used for combining the amplified signals.

Abstract: Examples disclosed herein relate to a vector modulator architecture, having an input splitter network configured to receive a radio frequency (RF) input signal and generate a plurality of quadrature signals at different phases, a variable gain amplifier (VGA) stage coupled to the input splitter network and configured to apply a first gain to one or more of the plurality of quadrature signals, a power combiner coupled to the VGA stage and configured to combine the plurality of quadrature signals into a combined RF signal, and a power amplifier (PA) stage coupled to the power combiner and configured to apply a second gain to the combined RF signal and generate an output RF signal. Other examples disclosed herein relate to an antenna system for autonomous vehicles and a radar system for use in an autonomous driving vehicle.

Abstract: Disclosed is an electronic device including an antenna module comprising a plurality of radio frequency (RF) chains, and a processor configured to control the antenna module, wherein each of the RF chains comprises an amplifier that amplifies power and a power detector, and wherein the antenna module further comprises a switching circuit that selectively switches between a first path and a second path, the first path being a connection through which an RF signal converted in the antenna module is transmitted to the power detector causing the RF signal to be detected, and the second path being a connection through which the RF signal is transmitted to the amplifier causing the power detector to detect an RF signal of the amplifier.

Abstract: It is configured to output a first I signal having passed through a first inverse characteristic circuit having inverse frequency characteristics to frequency characteristics of a first loop filter circuit, to the first loop filter circuit, and output a first Q signal having passed through a second inverse characteristic circuit having inverse frequency characteristics to frequency characteristics of a second loop filter circuit, to the second loop filter circuit.

Abstract: Disclosed are methods, systems, devices, apparatus, media, and other implementations, including a method for digital predistortion for a power amplifier system. The method includes determining one or more system characteristics for the power amplifier system comprising at least a power amplifier that produces output with non-linear distortions, with the one or more system characteristics corresponding to an estimate for a complex load metric for the power amplifier system coupled to a load. The method further includes determining, based on the one or more system characteristics corresponding to the estimate for the complex load metric, digital predistortion (DPD) coefficients to compensate for the nonlinear behavior of the power amplifier system.

Abstract: In a device and method for monitoring an RF transmission circuit of an MRI device: a first power measurement signal is acquired that indicates a voltage of a first RF signal provided by an RF power amplifier of the RF transmission circuit; two second power measurement signals are received that each indicate a voltage of one second RF signal, the two second RF signals being generated based on the first RF signal by a bridge of the circuit and transmitted via an RF transmit coil; an inverse matrix calculation is performed based on the two second power measurement signals to obtain a voltage calculation value; the voltage calculation value is compared with the first power measurement signal; an operational status of the RF transmission circuit is determined based on a difference between the voltage calculation value and a voltage value of the first power measurement signal.

Abstract: A device configured to perform wireless communication includes: a pre-distortion circuit configured to generate a pre-distorted input signal by performing pre-distortion on an input signal based on a parameter set comprising a plurality of coefficients; a power amplifier configured to generate an output signal by amplifying an RF signal based on the pre-distorted input signal; and a parameter obtaining circuit configured to obtain second memory polynomial modeling information corresponding to an operating frequency band based on first memory polynomial modeling information corresponding to each of a plurality of frequency sections and obtain a parameter set according to an indirect learning structure by using the second memory polynomial modeling information.

Abstract: A system and method for making improved measurements of integrated antenna arrays utilizes vector network analyzer (VNA) and a calibrated receive-side system comprising two antennae, dual reflectometers coupled to the two antennae for match correction, a wide band intermediate frequency (IF) strip which connects the receive-side system to the input ports of the VNA, an air gap which separates the receive-side system form the DUT, and a stepmotion baffle configure to be inserted into the air gap to modify antenna coupling. The system and method enable measurement of noise characteristics of the DUT including nonlinear effects of transmitter element coupling between the plurality of transmitter elements within an antenna array.

Abstract: Multi-level envelope tracking systems with separate DC and AC paths are provided. In certain embodiments, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a multi-level supply (MLS) DC-to-DC converter that outputs multiple regulated voltages, an MLS modulator that controls selection of the regulated voltages over time based on an envelope signal corresponding to an envelope of a radio frequency (RF) signal amplified by the power amplifier, an AC path filter coupled between an output of the MLS modulator and the power amplifier supply voltage, and a DC path filter coupled between a DC voltage and the power amplifier supply voltage.

Abstract: Methods and systems for power amplification with digital quantized power supply with multiple amplifiers are disclosed herein. In one embodiment, In one embodiment, a time-varying envelope signal is sampled, quantized and decomposed into several constituent signals that are individually amplified, and then combined to form a desired amplified version of the quantized time-varying envelope. Amplitude, phase and/or frequency characteristics of one or more of the signals and supply voltages Vdd and source current of one or more amplifiers are digital controlled based on the information provided by quantization process and slow and fast power control information. Amplitude, phase and/or frequency characteristics of one or more of the constituent signals to be amplified are controlled to provide the desired amplitude, phase, frequency, and/or spectral characteristics of the desired quantized version of the time-varying envelope signal.

Abstract: An antenna array module includes at least two antenna units mounted on a surface of a feed network circuit board with two power division circuits, and a filter mounted on a surface of the feed network circuit board with two coupling circuits. Each power division circuit includes an input end and a plurality of output ends. One power division circuit feeds an antenna unit for ?45° polarization, and the other power division circuit feeds an antenna unit for +45° polarization. Each coupling circuit includes a radio frequency input end and an output end, and the output end of the coupling circuit is electrically connected to the input end of the power division circuit. The filter includes at least two output ends that are electrically connected to the radio frequency input end of the coupling circuit. A base station antenna includes a mounting structure and a connection structure.

Abstract: A method for digital predistortion (DPD) calibration in a wireless communication device is provided that includes transmitting, by transmission circuitry of the wireless communication device, a plurality of pulses, where each pulse corresponds to an amplitude step in a pattern of amplitude steps, where the amplitude steps are separated by silence gaps, receiving each pulse in receiver circuitry of the wireless communication device, generating, by an accumulator component of the wireless communication device, an accumulated sample for each pulse based on a plurality of samples output by the receiver circuitry for the pulse, and computing, by a processor of the wireless communication device, amplitude dependent gain (AM/AM) and amplitude dependent phase shift (AM/PM) values for each accumulated sample.

Abstract: A pre-distorter that both accurately compensates for the non-linearities of a radio frequency transmit chain, and that imposes as few computation requirements in terms of arithmetic operations, uses a diverse set of real-valued signals that are derived from separate band signals that make up the input signal. The derived real signals are passed through configurable non-linear transformations, which may be adapted during operation, and which may be efficiently implemented using lookup tables. The outputs of the non-linear transformations serve as gain terms for a set of complex signals, which are functions of the input, and which are summed to compute the pre-distorted signal. A small set of the complex signals and derived real signals may be selected for a particular system to match the classes of non-linearities exhibited by the system, thereby providing further computational savings, and reducing complexity of adapting the pre-distortion through adapting of the non-linear transformations.

Abstract: An output power linearization method, suitable for a calibration system, includes the following operations: providing an instruction signal, which corresponding to a currently ideal output power among multiple ideal output powers, to an emission module of the calibration system so that the emission module outputs a radio frequency (RF) signal with a practical output power according to the instruction signal; obtaining a feedback signal, by a feedback circuit of the calibration system, from an output terminal of the emission module, and calculating a feedback output power from the feedback signal; calculating an output difference between the currently ideal output power and the feedback output power; if an absolute value of the output difference is larger than an absolute value of a feedback error of the feedback circuit, adjusting a present gain of the emission module so that the practical output power approaches the currently ideal output power.

Abstract: An embodiment of the invention is a time-delay invariant predistortion approach to linearize power amplifiers in wireless RF transmitters. The predistortion architecture is based on the stored-compensation or memory-compensation principle by using a combined time-delay addressing method, and therefore, the architecture has an intrinsic, self-calibrating time-delay compensation function. The predistortion architecture only uses a lookup table to conduct both the correction of non-linear responses of a power amplifier and the compensation of any time-delay effects presented in the same system. Due to the time-delay invariant characteristic, the predistortion design has a wider dynamic range processing advantage for wireless RF signals, and therefore can be implemented in multi-carrier and multi-channel wireless systems.

Abstract: A multistage amplifier includes: N amplifiers (N?2), a (k+1)th amplifier cascaded to a kth amplifier (1?k?N?1), and each amplifier being configured to amplify a multicarrier signal; and an extraction circuit including an input and an output, the input being connected to an output of a jth amplifier (1?j?N?1), and the output providing a compensation signal to an input of a (j+1)th amplifier or an output of the (j+1)th amplifier. The extraction circuit includes a filter circuit connected to the output of the jth amplifier that extracts a distortion frequency component of n times a differential frequency f2?f1 (n?1), a phase shifter cascaded to the filter circuit that shifts a phase of the component, and a gain adjustment circuit cascaded to the phase shifter that adjusts an amplitude of the component and generates the compensation signal.

Abstract: A delay circuit includes a state transition section configured to start state transition based on a trigger signal and output state information indicating the internal state and a transition-state acquisition section configured to latch and hold the state information. The state transition section includes a tapped delay line in which a plurality of delay elements are coupled, a logical circuit configured to generate a third signal based on a first signal based on the trigger signal and a second signal, which is an output signal of the delay element, and a synchronous transition section configured to count an edge of the third signal. The state information is having an output signal of the synchronous transition section and an output signal of the tapped delay line. A humming distance of the state information before and after the state transition is 1.

Abstract: Disclosed are methods, systems, devices, apparatus, media, design structures, and other implementations, including a method for digital predistortion of multiband signals that includes receiving a plurality of input signals respectively associated with multiple radio frequency (RF) bands, with the plurality of input signals occupying an input frequency span corresponding to a difference between a maximum frequency in a highest of the multiple RF bands and a minimum frequency in a lowest of the multiple RF bands. The method further includes frequency shifting at least one signal from the plurality of input signals to produce condensed shifted signals, each corresponding to a respective one of the plurality of input signals, occupying a condensed frequency span smaller than the input frequency span, and processing the condensed shifted signals, including applying digital predistortion to the condensed shifted signals.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for correcting distortion of radio signals A transmit radio signal corresponding to an output of a transmitting radio signal processing system is obtained. A pre-distorted radio signal is then generated by processing the transmit radio signal using a nonlinear pre-distortion machine learning model. The nonlinear pre-distortion machine learning model includes model parameters and at least one nonlinear function to correct radio signal distortion or interference. A transmit output radio signal is obtained by processing the pre-distorted radio signal through the transmitting radio signal processing system. The transmit output radio signal is then transmitted to one or more radio receivers.

Abstract: Disclosed are implementations, including a method comprising selecting a location of a selection buffer (that stores observed output samples produced by a signal chain) according to a pseudo-random buffer selection process, and accessing at least one observed output sample generated in response to corresponding input samples (to the system) and/or intermediary samples (outputs of a digital compensator) produced by a compensator of the system. The method further includes computing an approximation of a sub-gradient value computed according to a stochastic gradient process to derive a sub-gradient of an error function representing a relationship between the observed output sample, and the input and/or intermediary samples, computing updated values for the compensator coefficients based on current values of the coefficients and the approximation of the sub-gradient value, and replacing, at a time instance determined independently of the buffer selection process, content of part or all of the selection buffer.

Abstract: Disclosed are digital predistortion implementations, including a method that includes obtaining a first set of digital predistortion (DPD) non-linear functions for controlling operation of a digital predistorter of a wireless device operating on a received at least one input signal directed to a power amplification system comprising a transmit chain with at least one power amplifier that produces output with non-linear distortions. The method further includes determining an expanded set of DPD non-linear functions comprising the first set of DPD non-linear functions and additional one or more sets of DPD non-linear functions derived based on the first set of DPD non-linear functions and on operating condition parameters associated with operation of the wireless device, and configuring the digital predistorter with DPD coefficients determined for the expanded set of the DPD non-linear functions based on observed samples of the transmit chain responsive to the at least one input signal.

Abstract: A method for digital predistortion (DPD) calibration in a wireless communication device is provided that includes transmitting, by transmission circuitry of the wireless communication device, a plurality of pulses, where each pulse corresponds to an amplitude step in a pattern of amplitude steps, where the amplitude steps are separated by silence gaps, receiving each pulse in receiver circuitry of the wireless communication device, generating, by an accumulator component of the wireless communication device, an accumulated sample for each pulse based on a plurality of samples output by the receiver circuitry for the pulse, and computing, by a processor of the wireless communication device, amplitude dependent gain (AM/AM) and amplitude dependent phase shift (AM/PM) values for each accumulated sample.

Abstract: A dual-input voltage memory digital pre-distortion (mDPD) circuit and related ET apparatus are provided. In examples discussed herein, an ET apparatus includes an amplifier circuit(s) configured to amplify a radio frequency (RF) signal based on an ET voltage. A tracker circuit is configured to generate the ET voltage based on a number of target voltage amplitudes derived from a number of signal amplitudes of the RF signal. However, the tracker circuit can cause the ET voltage to deviate from the target voltage amplitudes due to various inherent impedance variations, particularly at a higher modulation bandwidth. In this regard, a dual-input voltage mDPD circuit is configured to digitally pre-distort the target voltage amplitudes based on the signal amplitudes such that the ET voltage can closely track the target voltage amplitudes. As such, it is possible to mitigate ET voltage deviation, thus helping to improve overall linearity performance of the ET apparatus.

Abstract: An apparatus of a transmitter and method are provided, the apparatus comprising a processor that calculates a supply voltage (SV) value (SVV) to provide as an SV for a power amplifier (PA) of the transmitter for transmissions during a transmission time slot (TS). When the SV<an envelope tracking (ET) threshold (ETT), then the processor configures the PA to transmit a signal in an average power tracking (APT) mode that maintains the SV at the SVV during the TS. When the SV?ETT, and an APT condition is met, then the processor configures the PA to transmit the signal in the APT mode. When the SV?ETT, and the APT condition is not met, then the processor transmits by an adjustment to the SVV to track an amplitude modulation envelope during the TS in an ET mode.

Abstract: A distortion compensation device includes a generating unit, a calculation unit, a conversion unit, and a distortion compensation unit. The generating unit generates, from an output signal of a power amplifying unit that amplifies transmission signals having a plurality of different bands, a superimposed signal in which the transmission signals having the different bands have been superimposed. The calculation unit calculates, based on the superimposed signal, a coefficient indicating a forward characteristic of nonlinear distortion of the power amplifying unit associated with each of the transmission signals having the different bands. The conversion unit converts the coefficient calculated by the first calculation unit to a coefficient indicating an inverse characteristic of the nonlinear distortion of the power amplifying unit.

Abstract: Communication devices and methods are provided which enable communication both with modulo receivers and legacy receivers. Different types of precodings are used in a joint precoding to reduce crosstalk between communication connections to all receivers.

Abstract: Certain aspects of the present disclosure introduce transmit chain asymmetry to meet tighter specifications of a band on one side of a spectrum while sacrificing emissions margin of a band on the opposite side of the spectrum. One example apparatus generally includes a distortion module configured to generate an input signal, and an amplifier coupled to the distortion module and configured to generate an amplified signal based on the input signal. In certain aspects, the input signal is generated such that a power of the amplified signal at a first bandwidth is skewed relative to a power of the amplified signal at a second bandwidth, the first and second bandwidths being adjacent to a main channel bandwidth of the amplified signal.

Abstract: A radio frequency front-end circuit performs, in a communication band made up of a plurality of communication channels within a particular frequency band used in a system, wireless communication through a use channel selected from among empty communication channels in the plurality of communication channels, the radio frequency front-end circuit including a transmission-side amplifier circuit and a transmission circuit both serving as a transmission-side circuit that produces, from a transmitted signal after being subjected to a predistortion process, a transmitted signal corresponding to the use channel, and a frequency variable filter serving as a tunable filter that attenuates a radio frequency signal of a spurious wave at least in an alternate adjacent channel relative to the use channel.

Abstract: A circuit and apparatus for filtering harmful harmonics is disclosed. The circuit and apparatus include a power amplifier core that uses equally sized inverter based amplifiers. The amplifier core cells provide uniform load to all phases of a fundamental frequency to cancel all harmonics at an output. The power amplifier stages are driven into nonlinearity, and the combination of harmonics is performed at the output by varying series connected capacitors. The harmonic combination is performed at the outputs, leaving no further scope of nonlinearity in the signal chain.

Abstract: A pre-distorter that both accurately compensates for the non-linearities of a radio frequency transmit chain, and that imposes as few computation requirements in terms of arithmetic operations, uses a diverse set of real-valued signals that are derived from the input signal. The derived real signals are passed through configurable non-linear transformations, which may be adapted during operation, and which may be efficiently, implemented using lookup tables. The outputs of the non-linear transformations serve as gain terms for a set of complex signals, which are functions of the input, and which are summed to compute the pre-distorted signal. A small set of the complex signals and derived real signals may be selected for a particular system to match the classes of non-linearities exhibited by the system, thereby providing further computational savings, and reducing complexity of adapting the pre-distortion through adapting of the non-linear transformations.

Abstract: In certain aspects of the present disclosure, a method for wireless communication comprises predistorting a first signal based on a set of coefficients to generate a first predistorted signal, outputting the first predistorted signal for a first transmission to a receiving device, and receiving a first feedback signal from the receiving device, wherein the first feedback signal provides feedback of a first receive signal at the receiving device corresponding to the first transmission. The method also comprises determining whether to store the set of coefficients in a memory based on the received first feedback signal, and storing the set of coefficients in the memory based on the determination.

Abstract: A front-end module, which uses a carrier aggregation method in which communication is performed by simultaneously using Band 8 and Band 3, includes an antenna switch module that switches connections between an antenna and a plurality of signal paths, a first circuit that is connected to a Band 8 signal path, and a second circuit that is connected to a Band 3 signal path and is electromagnetic-field coupled with the first circuit. A signal including a Band 3 frequency component that propagates from the signal path to the signal path via the antenna switch module and a signal including a Band 3 frequency component that propagates from the signal path to the signal path via the first circuit and the second circuit have a phase-shifted relationship with each other.