Abstract: Provided is a joint pattern beam sectorization method and apparatuses for performing the same, wherein the joint pattern beam sectorization method including generating, in a service target region, a pattern sector corresponding to an antenna array including antennas having an identical radiation pattern by using the antenna array and generating pattern beam sectors in the pattern sector through a beamforming using the antennas.

Abstract: A power amplification module includes a first input terminal arranged to receive a first transmission signal in a first frequency band, a second input terminal arranged to receive a second transmission signal in a second frequency band higher than the first frequency band, a first amplification circuit that amplifies the first transmission signal, a second amplification circuit that amplifies the second transmission signal, a first filter circuit located between the first input terminal and the first amplification circuit, and a second filter circuit located between the second input terminal and the second amplification circuit. The first filter circuit is a low-pass filter that allows the first frequency band to pass therethrough and that attenuates a harmonic of the first transmission signal and the second transmission signal. The second filter circuit is a high-pass filter that allows the second frequency band to pass therethrough and that attenuates the first transmission signal.

Abstract: An RF or other high frequency transceiver including a loopback reference channel for measurement of an absolute power level. A transmit channel in the transceiver includes a programmable power amplifier that can be controlled to operate at a selected power level, and a receive channel including a receive amplifier, mixers, filters, and analog-to-digital converters. The loopback reference channel includes a self-biased amplifier, followed by a series of buffers that generate a square wave from the received signal, and an attenuator applying an attenuation gain to the square wave. The transmit power at a programmed power level can be calculated from ratios of a measured power level of a transmitted signal as received by the receive channel to the measured power level of the transmitted signal using the loopback reference channel.

Abstract: An apparatus and method for controlling wireless transmission. The apparatus, which controls a transmitter that provides an output signal by upconverting and amplifying an input signal, includes a memory configured to store first calibration data representing a saturation power and a linear gain of a reference transmitter as functions of operating conditions of the reference transmitter. A controller may be configured to estimate a saturation power and a linear gain of the transmitter of the apparatus based on operating conditions of the transmitter and the first calibration data. The controller may generate at least one control signal for controlling an operation of the transmitter based on a saturation power difference between the estimated saturation power and a target saturation power and a linear gain difference between the estimated linear gain and a target linear gain.

Abstract: Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Abstract: A cellular radio architecture that includes a transceiver front-end circuit including an antenna and a switch module having a switching network that directs analog transmit signals to be transmitted to the antenna and receives receive signals from the antenna. The architecture further includes a receiver module having a separate signal channel for each of the signal paths in the multiplexer module, where each signal channel in the receiver module includes a receiver delta-sigma modulator that converts analog receive signals to a representative digital signal. The architecture also includes a transmitter module having a transmitter delta-sigma modulator for converting digital data bits to the transmit signals. The transmitter module includes a tunable bandpass filter and a power amplifier for amplifying the transmit signals before transmitting. The architecture also includes a calibration feedback and switch module that receives the amplified signals from the power amplifier.

Abstract: A distortion compensation device includes: a signal processing unit to perform signal processing on a symbol; a storage unit to store a distortion compensation value for every pattern string including a symbol of interest and predetermined number of symbols ahead of the symbol of interest among a plurality of input symbols, a distortion in the signal processing unit being compensated for such that the symbol of interest is corrected to a target value based on the distortion compensation value; a first acquisition unit to acquire a pattern string of interest including the current input symbol and the predetermined number of input symbols ahead of the current input symbol; a second acquisition unit to acquire the distortion compensation value associated with the pattern string of interest from the storage unit; and a setting unit to set the distortion compensation value to a correction value of the signal processing unit.

Abstract: This disclosure provides a circuit for linearizing an output signal Sout produced by a non-linear component based on an input signal x(n). The circuit comprises a primary pre-distorter module configured to generate a pre-distorted signal y(n) based on the input signal x(n) and a primary pre-distortion function parameterized by a pre-distortion parameter ? and to feed the pre-distorted signal y(n) to the non-linear component. The circuit comprises an estimation module. The estimation module is configured to receive samples z(n) of the output signal Sout, and to determine the pre-distortion parameter ?. The estimation module comprises a secondary pre-distorter module configured to generate a secondary pre-distorter output signal r(n) based on a secondary pre-distortion function and the samples z(n) of the output signal Sout.

Abstract: An apparatus relates generally to preconditioning an input signal. In this apparatus, a first digital predistortion module and a second digital predistortion module are for receiving the input signal for respectively providing a first predistorted signal and a second predistorted signal. A combiner is for combining the first predistorted signal and the second predistorted signal for providing an output signal. The first digital predistortion module includes a moving mean block for receiving the input signal for providing a moving mean signal. The first digital predistortion module further includes a digital predistorter for receiving the input signal and the moving mean signal for providing the first predistorted signal.

Abstract: A method, system, and device provide power-efficient communications within the context of available power. Transmission and receipt data rates are scalable in accordance with output power available from a power source. Data is transmitted at a data rate determined, at least in part, by the available output power.

Abstract: Apparatus and a method for predistortion of a radio-frequency signal are described. At least one predistortion unit is described that is arranged to receive an analog baseband signal before amplification and to generate an analog predistortion signal based on said analog baseband signal. At least one mixer unit is also described and may be electrically coupled to the at least one predistortion unit. In this case, the at least one mixer unit is arranged to receive the analog baseband signal before amplification and the analog predistortion signal and to generate a weighted combination of said signals.

Abstract: A non-linear pre-distortion engine maintaining constant peak power at its output is disclosed. The engine includes a compression estimator, a crest factor reduction processor, a digital pre-distorter and a power amplifier. The compression estimator is configured to generate a compression estimate based on an input signal and a feedback signal. The feedback signal is based on an RF output signal. The crest factor reduction processor is configured to reduce a crest factor of the input signal to generate a crest factor reduced signal based on the compression estimate. The digital pre-distorter is configured to apply a pre-distortion to the crest factor reduced signal after an initial phase and generate a pre-distorted signal based on pre-distortion parameters. The power amplifier is configured to amplify the pre-distorted signal to generate the RF output signal.

Abstract: A method including determining whether a transmitter of an apparatus has information to transmit; and causing a power amplifier of said apparatus to enter a first power state in response to said determining; wherein said determining is carried out within a radio portion of said apparatus.

Abstract: Various embodiments of the invention provide for improved performance by reducing a quadrature error signal. In certain embodiments, this is accomplished by using a mixed-signal architecture comprising analog and digital circuit components in a closed-loop configuration that generates from a detected quadrature error signal a calibration quadrature signal that is then compensated at a virtual ground of an analog front end circuit. Some embodiments allow for pre-calibration for quadrature error and/or adaptive compensation of unwanted drift effects of the quadrature error, including temperature drifts.

Abstract: The invention is a method and a system for updating pre-distortion coefficients, which is used to solve the problem of interference with neighbor cells due to the inferior pre-distortion coefficients. The method includes: presetting a primary table and a standby table, which store default and updated pre-distortion coefficients respectively; when a data source of a pre-distortion processor adopts the standby table, adopting the updated pre-distortion coefficients to perform parameter output processing to acquire pre-distortion parameters, and conveying the pre-distortion parameters and an input signal to the pre-distortion processor to process to acquire pre-distortion signals; conveying the pre-distortion signals through various signal processors to acquire a first signal, and determining the power data of the first signal; and based on the comparing result of the power data of the first signal and a setting range, there are different actions.

Abstract: A radio frequency (RF) amplification circuit and a closed-loop amplitude linearization circuit are disclosed. The RF amplification circuit amplifies an RF signal to generate an amplified RF signal. The RF amplification circuit and the closed-loop amplitude linearization circuit form a fast control loop and a slow control loop. The slow control loop estimates a total radiated power (TRP) from the RF amplification circuit to create a TRP estimate using a representation of the amplified RF signal, and controls a fast loop gain of the fast control loop based on the TRP estimate. The fast control loop applies a gain adjustment to the RF amplification circuit based on the fast loop gain and a difference between a target reference amplitude and a measured feedback amplitude. The gain adjustment controls amplitude distortion in the RF amplification circuit. The fast loop gain controls TRP-drift in the RF amplification circuit.

Abstract: A radio frequency signal transceiver includes: a transmission circuit configured to perform power amplification on an input first analog signal, wirelessly transmit the first analog signal after power amplification, and output the first analog signal after power amplification to a pre-distortion circuit; the pre-distortion circuit configured to convert the first analog signal after power amplification into a second analog signal and output the second analog signal, where the second analog signal is used to feedback distortion of the first analog signal to compensate the first analog signal in advance according to the distortion; and a receiving circuit configured to wirelessly receive a third analog signal, and process and output the third analog signal. The radio frequency signal transceiver can improve efficiency in receiving and transmitting a radio frequency signal, reduce a cost of a base station system, and reduce a difficulty in implementing the base station system.

Abstract: Control systems and methods for power amplifiers operating in envelope tracking mode are presented. A set of corresponding functions and modules are described and various possible system configurations using such functions and modules are presented.

Abstract: A tuner receives a received signal using one of a plurality of transmission formats that use at least one of either a first frequency or a second frequency band. A determination unit determines the transmission format being used in the received signal from among the plurality of transmission formats. In the determination unit, a pattern matching unit stores in advance a plurality of patterns respectively expressing a received waveform of a preamble in each of the plurality of transmission formats, conducts a pattern matching process between the received signal and the each of the plurality of patterns, and obtains a correlation value. A transmission mode determination unit determines the transmission format being used in the received signal on the basis of the correlation value.

Abstract: One example embodiment provides a system, apparatus, and method for using polynomial models in tone calibration for quadrature error correction in I/Q receivers. In one example embodiment, method for calibrating an I/Q receiver is provided and includes receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.

Abstract: Digital pre-distortion (DPD) systems are often used to improve the linearity of a power amplifier in transmitters. These DPD systems are typically implemented in baseband (prior to modulation). However, ever increasing signal bandwidth requirements limits the practicality of DPD systems implemented in baseband. A DPD system in the radio frequency (RF) domain (as opposed to in baseband) can solve this problem and further improve a DPD system's ability to correct for distortions. The RF domain DPD system is upstream from a digital-to-analog converter, and performs DPD after a baseband signal is up-sampled into the RF domain (after the modulation process). When compared against a baseband DPD system, the RF domain DPD system can handle significantly wider bandwidth, and has an improved ability to linearize a wide variety of distortions present in the spectrum.

Abstract: A random jitter beamforming method for reducing the influence of a side lobe to decrease a beam width, and a transmitter and a receiver using the same are provided. The random jitter beamforming method includes dividing a series of binary sequences to generate a plurality of bit groups, designating a beam pattern, corresponding to each of the bit groups, from a set of two or more beam patterns having the same gain and phase in a target direction, and forming a beam with the corresponding beam pattern, for each of the bit groups.

Abstract: A predistortion function is evaluated with in-phase (I) and quadrature (Q) data words as arguments, while additive I and Q data words are generated in accordance with a comparison of the I and Q data words with a full scale value that generates maximum current in a digital power amplifier. The additive I and Q data words are added to the computed I and Q data words to produce predistorted I and Q data words. The predistorted I and Q data words are provided in a sequence to the digital power amplifier, which generates a corresponding radio-frequency (RF) analog signal.

Abstract: Systems and methods are disclosed for digital predistortion for a concurrent multi-band transmitter using a single adaptor and a same set of predistortion coefficients for separate digital predistorters for each band. In one embodiment, the single adaptor is configured to adaptively configure a set of predistortion coefficients based on a memory polynomial digital baseband model of the digital predistorters having a same set of predistortion coefficients for each of the digital predistorters. By using the same set of predistortion coefficients for the separate digital predistorters for each band, a complexity of the digital predistortion is substantially reduced.

Abstract: A method, system, and device provide power-efficient communications within the context of available power. Transmission and receipt data rates are scalable in accordance with output power available from a power source. Data is transmitted at a data rate determined, at least in part, by the available output power.

Abstract: Transmitter observation receivers and methods are described that can predistortion-compensate transmitters capable of operating in multiple communication bands and frequency ranges. Such observation receivers and method involve generating at least one compensation signal such that a signal to be transmitted that is within a bandwidth that simultaneously encompasses multiple frequency ranges is compensated.

Abstract: A distortion compensation device includes: a memory configured to store a first and second table, different addresses being assigned to the first and second table respectively, each of the addresses being related to a distortion compensation coefficient to compensate for a non-linear distortion, a first address in the first table and a second address in the second table corresponding to respective first and second ranges of power or amplitude of a transmission signal, and parts of the first and second ranges overlapping each other; and a processor coupled to the memory and configured to: update the respective distortion compensation coefficients related to the first address and the second address simultaneously, in accordance with a single value of the power or the amplitude, and compensate for the non-linear distortion generated by an amplifier amplifying the power of the transmission signal, by using at least one of the first and second table.

Abstract: A system for calibrating a power amplifier (PA) includes a memory, a processor, a digital pre-distorter (DPD), and a data converter. The DPD includes a programming interface module, a pattern generator, a multiplier, and a pre-distorter module. The multiplier multiplies reference baseband stream data from the memory with pattern coefficient data generated by the pattern generator to generate shaped reference baseband stream data. The pre-distorter module generates pre-distorted shaped reference baseband stream data. The PA receives a low-power reference radio frequency (RF) signal corresponding to the pre-distorted shaped reference baseband stream data and generates a high-power reference RF signal.

Abstract: An apparatus for wireless relaying comprises: a transmission unit for generating a wireless signal; an amplification unit for amplifying and outputting the wireless signal; a conversion unit for converting the wireless signal into a digital signal; and an adjustment unit for adjusting the amplification ratio of the amplifying unit so that the difference between an output level value of the digital signal and a predetermined target power is lower than a predetermined numerical value.

Abstract: A communication device with a power detection scheme is disclosed. The communication device includes a transmitter for transmitting an RF signal, a demodulator for demodulating the RF signal by utilizing a phase-modulated (PM) signal provided from the transmitter to generate a demodulated signal, a loopback circuit coupled between the transmitter and the demodulator for transmitting the RF signal and the PM signal from the transmitter to the demodulator when the power detection scheme is enabled, and a power detector for detecting power of the demodulated signal.

Abstract: A method of compensating carrier tone generation between duty cycles includes receiving a carrier frequency signal and a reference frequency signal, where the carrier frequency signal is mixed with a communication signal in a signal path. The method includes determining a first and second time differences between the carrier frequency signal and the reference frequency signal at respective clock edges of the reference frequency signal. The method includes converting the first time difference to a first corresponding phase value and the second time difference to a second corresponding phase value based on an operating frequency, and determining a phase difference between the first corresponding phase value and the second corresponding phase value. In turn, the method includes adjusting the communication signal with the phase difference independent of the signal path to maintain phase continuity in the signal path between the duty cycles.

Abstract: The present disclosure relates to envelope power supply calibration of a multi-mode RF power amplifier (PA) to ensure adequate headroom when operating using one of multiple communications modes. The communications modes may include multiple modulation modes, a half-duplex mode, a full-duplex mode, or any combination thereof. As such, each communications mode may have specific peak-to-average power and linearity requirements for the multi-mode RF PA. As a result, each communications mode may have corresponding envelope power supply headroom requirements. The calibration may include determining a saturation operating constraint based on calibration data obtained during saturated operation of the multi-mode RF PA. During operation of the multi-mode RF PA, the envelope power supply may be restricted to provide a minimum allowable magnitude based on an RF signal level of the multi-mode RF PA, the communications mode, and the saturation operating constraint to provide adequate headroom.

Abstract: Circuitry, which includes a linear amplifier, is disclosed. The linear amplifier has a linear amplifier output and includes an input amplifier stage and an output amplifier stage. The output amplifier stage at least partially provides an envelope power supply voltage to a radio frequency (RF) power amplifier (PA) via an envelope power supply output using a selected one of a group of linear amplifier power supply signals. The group of linear amplifier power supply signals includes at least a first bi-directional power supply signal. The input amplifier stage selects the one of the group of linear amplifier power supply signals based on the envelope power supply voltage and a setpoint of the envelope power supply voltage.

Abstract: Embodiments provide methods, apparatus and computer software for use in calibrating a transmitter in operative association with a variable supply voltage. A phase distortion of the power amplifier is determined for a given instantaneous power. On the basis of the determined phase distortion for the power amplifier at the given instantaneous power, the transmitter is calibrated. Examples of transmitters in respect of which embodiments may be practiced include envelope tracking transmitters, envelope elimination and restoration transmitters, and polar transmitters.

Abstract: Distortions of both amplitude and phase along a transmission line are compensated for by a trace canceller inserted between a transmitter and a receiver. The trace canceller has an equalizer that compensates for a trace length between the transmitter and the trace canceller. A variable gain amplifier between the equalizer and an output buffer has its gain controlled by an automatic gain control circuit that compares low-frequency swings of the input and output of the trace canceller. The gain of the variable gain amplifier is reduced to prevent the output buffer from saturating and clipping peak voltages on its output. Thus both the variable gain amplifier and the output buffer remain in the linear region. Training pulses from the transmitter are passed through the trace canceller without clipping of peak voltages, allowing the transmitter and receiver to adjust transmission parameters to best match the transmission line.

Abstract: A method of calibrating an envelope tracking system for a supply voltage for a power amplifier module within a radio frequency (RF) transmitter module of a wireless communication unit. The method includes, within at least one signal processing module of the wireless communication unit, determining combinations of the power amplifier supply voltage and power amplifier input power that provide a power amplifier output power equal to a target output power, obtaining battery current indications for the determined combinations of the power amplifier supply voltage and power amplifier input power, selecting a combination of the power amplifier supply voltage and power amplifier input power that provide a power amplifier output power equal to a target output power based at least partly on the obtained battery current indications therefore, and calibrating the envelope tracking system using the selected combination of the power amplifier supply voltage and power amplifier input power.

Abstract: RF PA circuitry includes an amplifier stage, gain compensation circuitry, and an adder. The amplifier stage is configured to receive and amplify an RF input signal to provide an RF output signal. The gain compensation circuitry is coupled in parallel with the amplifier stage and configured to receive the RF input signal and provide a gain compensation signal, wherein the gain compensation signal is configured to linearize at least a portion of the gain response of the amplifier stage or the RF PA circuitry in general. The adder is coupled between an output of the amplifier stage and the gain compensation stage and is configured to receive and add the RF output signal and the gain compensation signal to provide a linearized RF output signal.

Abstract: Apparatus and methods disclosed herein perform gain, clipping, and phase compensation in the presence of I/Q mismatch in quadrature RF receivers. Gain and phase mismatch are exacerbated by differences in clipping between I & Q signals in low resolution ADCs. Signals in the stronger channel arm are clipped differentially more than weaker signals in the other channel arm. Embodiments herein perform clipping operations during iterations of gain mismatch calculations in order to balance clipping between the I and Q channel arms. Gain compensation coefficients are iteratively converged, clipping levels are established, and data flowing through the network is gain and clipping compensated. A compensation phase angle and phase compensation coefficients are then determined from gain and clipping compensated sample data. The resulting phase compensation coefficients are applied to the gain and clipping corrected receiver data to yield a gain, clipping, and phase compensated data stream.

Abstract: A method of calibrating an envelope tracking system for a supply voltage for a power amplifier module within a radio frequency (RF) transmitter module. The method includes deriving a mapping function between an instantaneous envelope of a waveform signal to be amplified by the power amplifier module and the power amplifier module supply voltage to achieve a constant power amplifier module gain based on a gain compression factor, setting an envelope tracking path of the transmitter module into an envelope tracking mode in which mapping between the instantaneous envelope of the waveform signal and the power amplifier module supply voltage is performed using the derived mapping function, applying a training signal comprising an envelope that varies with time to the RF transmitter module, measuring a battery current, modifying the gain compression factor based on the measured battery current, and re-deriving the mapping function based on the modified gain compression factor.

Abstract: A method and apparatus for controlling update of digital pre-distortion (DPD) coefficient is provided. The apparatus is applicable to a digital power control system, wherein the apparatus comprises: an update controlling unit configured to determine a group of fully-trained DPD coefficients among a plurality of DPD coefficients; and a DPD coefficient generating unit configured to update adaptively the group of fully-trained DPD coefficients according to the result of judgment of the update controlling unit. The DPD coefficients are allowed to be updated after being judged as being able to be fully trained according to power distribution information of DPD input signals, or according to address distribution information of an LUT, or according to average power of output of an HPA; otherwise, they may not be updated, thereby efficiently preventing DPD abnormality resulted from unfull training of coefficients in being updated.

Abstract: To satisfy the required SNR values for each system and/or each channel, a peak factor reduction device for reducing peak components included in a transmission signal, generates a cancellation signal to be multiplexed on the transmission signal, and the peak factor reduction device changes an amplitude of the generated cancellation signal according to a signal noise ratio required for the transmission signal and a power level of the transmission signal.

Abstract: The present disclosure relates to envelope power supply calibration of a multi-mode RF power amplifier (PA) to ensure adequate headroom when operating using one of multiple communications modes. The communications modes may include multiple modulation modes, a half-duplex mode, a full-duplex mode, or any combination thereof. As such, each communications mode may have specific peak-to-average power and linearity requirements for the multi-mode RF PA. As a result, each communications mode may have corresponding envelope power supply headroom requirements. The calibration may include determining a saturation operating constraint based on calibration data obtained during saturated operation of the multi-mode RF PA. During operation of the multi-mode RF PA, the envelope power supply may be restricted to provide a minimum allowable magnitude based on an RF signal level of the multi-mode RF PA, the communications mode, and the saturation operating constraint to provide adequate headroom.

Abstract: A transmitter (32) generates a time-varying stabilized bias signal (82) from which an amplifier-generated, sub-RF distortion signal (26) has been canceled. The distortion signal (26) is a byproduct of amplification and is generated due to imperfect linearity and/or other characteristics of a linear RF power amplifier (36). An envelope amplifier (84) includes a high bandwidth differential input, linear, bias signal amplifier (120) and a low bandwidth switching amplifier (122) coupled together to achieve both a high bandwidth and high efficiency. A control loop (154) feeds a portion of the voltage V(t) from a conduction node (146) of the RF power amplifier (36) to one of the differential inputs of the linear bias signal amplifier (120), while a bias control signal (92) drives the other differential input. The portion of voltage V(t) fed to bias signal amplifier (120) is a low power portion from which the RF portion has been removed.

Abstract: 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.

Abstract: The output of a Radio Frequency (RF) Power Amplifier (PA) is sampled and down-converted, and the amplitude envelope of the baseband feedback signal is extracted. This is compared to the envelope of a transmission signal, and the envelope tracking modulation of the RF PA supply voltage VCC is adaptively pre-distorted to achieve a constant ISO-Gain (and phase) in the RF PA. In particular, a nonlinear function is interpolated from a finite number gain values calculated from the feedback and transmission signals. This nonlinear function is then used to pre-distort the transmission signal envelope, resulting in a constant gain at the RF PA over a wide range of supply voltage VCC values. Since the gains are calculated from a feedback signal, the pre-distortion may be recalculated at event triggers, such as an RF frequency change. Furthermore, the method improves nonlinearity in the entire transmitter chain, not just the RF PA.

Abstract: A system and method for remotely monitoring, communicating with, and reconfiguring power amplifier systems. A communications link is provided in field-deployed PA systems, for enabling remote communication with appropriate digital components such as microprocessors or other communications-capable portions of the power amplifier systems. The communications link permits operating parameters of the PA to be monitored and sent back to a remote terminal such as a web server or other computer mainframes via any suitable wired or wireless connection including internet, Ethernet, wireless, WiFi, WiMAX, cellular, local area networks (LAN), wide area networks (WAN), Bluetooth, and so forth. The communication is bi-directional, so that the remote host can download to the PA updates, cMobile operators and/or other service providers can reduce significant operating and capital expenses related to their radio networks maintenance and PA replacement by practicing this invention.

Abstract: The present invention relates to clipping thresholds adjustment for Crest Factor Reduction CFR in a radio unit, wherein the radio unit comprises one or more clipping stages that apply respective clipping thresholds to clip input signals, comprising: determining a target threshold for the clipping stages based on a target PAR and the amplitudes or powers of the input signals, estimating the direction in which original PAR of the input signals changes by comparing amplitudes of the clipped signals from the clipping stages with the target threshold, and adjusting the clipping thresholds based on the estimated direction. The present invention also relates to dynamic stage control. With the present invention, clipping thresholds and clipping stages are adaptively changes with dynamic original PAR of input signals and the efficiency of power amplifier is increased with a low implementation cost.

Abstract: An apparatus and method of linearization of a digitally-controlled pre-power amplifier (DPA) and RF power amplifier (PA) for performing predistortion calibration to compensate for nonlinearlities in the DPA and PA circuits. A predistortion look up table (LUT) stores measured distortion compensation data that is applied to the TX data before being input to the digital-to-frequency converter (DFC), DPA and PA. The on-chip receiver, which is normally inactive during the TX burst in a half-duplex operation, demodulates the RF PA output and uses the digital I/Q RX outputs to perform calibration of the TX pre-distortion tables. A sample of the RF output signal is provided to the receiver chain. While the PA (DPA) code is increasing (or decreasing), the amplitude and phase of the recovered I/Q samples are used to determine the instantaneous value of the AM/AM and AM/PM pre-distortion from which an update to the predistortion tables may be computed.

Abstract: Single-bit transmitter modulator having a digital pulse shaping filter configured to shape data pulses of an inphase signal and quadrature signal; an upsampling filter configured to increase the sample rate of the inphase signal and quadrature signal; a sigma-delta modulator providing a one-bit inphase output signal and a one-bit quadrature output signal; an inphase low-order analog low pass filter coupling the one-bit inphase output signal to an inphase channel input of a quadrature modulator, and a quadrature low-order analog low pass filter coupling the one-bit quadrature output signal to a quadrature channel input of a quadrature modulator; and, wherein the quadrature modulator is connected to a carrier signal generator and is configured to generate an inphase and quadrature modulated carrier.

Abstract: The present disclosure relates to envelope power supply calibration of a multi-mode RF power amplifier (PA) to ensure adequate headroom when operating using one of multiple communications modes. The communications modes may include multiple modulation modes, a half-duplex mode, a full-duplex mode, or any combination thereof. As such, each communications mode may have specific peak-to-average power and linearity requirements for the multi-mode RF PA. As a result, each communications mode may have corresponding envelope power supply headroom requirements. The calibration may include determining a saturation operating constraint based on calibration data obtained during saturated operation of the multi-mode RF PA. During operation of the multi-mode RF PA, the envelope power supply may be restricted to provide a minimum allowable magnitude based on an RF signal level of the multi-mode RF PA, the communications mode, and the saturation operating constraint to provide adequate headroom.