Abstract: A polar modulator of the present invention includes: a first function block which generates an amplitude signal and a phase signal; a second function block which adjusts the signal delay between the amplitude signal and the phase signal; a third function block which allows the low frequency component of the amplitude signal to pass therethrough; a fourth function block which modulates the phase of the phase signal; a fifth function block which outputs a modulation voltage, based on the amplitude signal; a sixth function block which modulates the amplitude of the phase signal, based on the modulation voltage; a seventh function block which measures the temperature of at least one function block; and an eighth function block which calculates a compensation amount for the signal delay, based on the measured temperature. The second function block adjusts the signal delay, based on the compensation amount.

Abstract: A wireless communication device includes a mixer that multiplies quadrature-modulated transmission data by a local oscillation frequency signal and outputs a high-frequency signal; a distributor that distributes the high-frequency signal; a detector circuit that detects a direct current component included in the high-frequency signal, based on the high-frequency signal distributed by the distributor; a correction signal generating unit that generates a correction signal for removing the direct current component from the high-frequency signal, based on the direct current component detected by the detector circuit; a correction unit that corrects the high-frequency signal by the correction signal generated by the correction signal generating unit; and a transmission unit that transmits the high-frequency signal that has been corrected by the correction unit.

Abstract: Systems and methods for communicating with a radio frequency (RF) device are disclosed herein. In particular, a method of the present disclosure includes: listening for a first hailing signal to be received on at least one hailing channel selected from a plurality of hailing channels, selecting at least one hailing channel based upon a system time and a node identification; determining a noise floor for the at least one hailing channel; and upon receiving a noise signal on the at least one hailing channel, adjusting the noise floor in response to the noise signal.

Abstract: An apparatus for implementing digital baseband predistortion includes a transmission channel including a digital-to-analog converter, a modulator, an amplifier and a power amplifier, and further includes a feedback channel analog part including a diode detector, a filter and an analog-to-digital converter, and a feedback channel digital part including a predistorter, a mode obtaining unit, a predistortion coefficient generator and a feedback correcting unit. The diode detector is configured to obtain an envelope of an output signal of the power amplifier. Embodiments of the present invention further provide a method for implementing digital baseband predistortion by applying the foregoing single-chip. Due to a simple structure of the diode detector, not only the number of radio frequency devices on the feedback channel is reduced, implementation complexity of hardware is lowered, power consumption is reduced, but also a feedback channel analog part may be integrated onto the single-chip.

Abstract: A power amplifying apparatus is provided. A reference signal generator provides a reference signal having an enabling state and a disabling state. A digital power amplifier generates a current based on the reference signal and an input signal. An output signal of the digital power amplifier is related to the current. When the reference signal is in the enabling state, the current is related to the input signal. When the reference signal is in the disabling state, the current is irrelevant to the input signal. During the enabling state of the reference signal, a data generator provides an output alternating between an in-phase signal and a quadrature-phase signal as the input signal to the digital power amplifier. When the reference signal is in the disabling state, the data generator provides a fixed signal as the input signal to the digital power amplifier.

Abstract: Apparatus and methods are disclosed related to low-voltage radio transmitters with high spectral purity. One such apparatus includes a baseband path with a predistortion stage, a programmable filter, and an upconverter core. In an embodiment, the programmable filter is placed between the predistortion stage and the upconverter core. In an embodiment, the programmable filter is configured by a controller to reject out-of-band noise introduced at the predistortion stage or earlier.

Abstract: Circuits and methods are disclosed for reducing interference from transmitter leakage in a radio transceiver. An exemplary method for reducing interference from transmitter leakage in a radio transceiver comprises downconverting, filtering, and sampling a radio frequency signal comprising a desired signal and a transmitter leakage signal to obtain a sampled signal of interest. The method further comprises generating a sampled distortion signal estimate that estimates one or more distortion products of the transmitter leakage signal, such as a squared amplitude obtained from a square-law device or corresponding digital function. Finally, the method comprises combining the sampled distortion signal estimate with the sampled signal of interest to obtain interference-reduced signal samples.

Abstract: In an emphasis optimization device, a calculating unit calculates an inverse characteristic of an amplitude characteristic based on the amplitude characteristic of a transmission path, and an inverse Fourier transform unit performs an inverse Fourier transform on the inverse characteristic to obtain an impulse response. An extracting unit extracts, from the obtained impulse response, an impulse response corresponding to the number of taps necessary for emphasis to be added to a digital signal to be transmitted on the transmission path. An emphasis amount calculating unit converts the extracted impulse response into a value of the emphasis to calculate an emphasis amount.

Abstract: An apparatus is provided to include a detector. The detector can detect that an interfering communications connection to a received satellite system signal in a mobile terminal is to be established by the mobile terminal. The apparatus include a processor that can prevent interference to the received satellite system signal due to the interfering communications connection by controlling uplink resource allocation of the mobile terminal based on the detection.

Abstract: Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Abstract: A user equipment is able to transmit, to a wireless access node, an indication of in-device coexistence (IDC) interference between the wireless interfaces. The user equipment can include a counter to track a number of transmissions having the indication of IDC interference.

Abstract: An apparatus and a method for controlling power in a wireless communication system are provided. The method includes receiving interference information comprising a resource usage rate, from at least one neighboring BS, calculating a throughput variance amount, which is expected if the serving BS changes power, experienced by the at least one neighboring BS, by using the interference information, calculating a throughput variance amount, which is expected if the serving BS changes power, of at least one Mobile Station (MS) having access to the serving BS, and controlling power for the at least one MS by using the throughput variance amount experienced by the at least one neighboring BS and the throughput variance amount of the at least one MS. The interference information represents a throughput variance amount generated in the at least one neighboring BS when the serving BS changes the power.

Abstract: A feedback method for interference alignment in wireless network having K transmitters and K receivers, the method including: transmitting, by a transmitter n?1, a precoding vector of the transmitter n?1 (n being an integer between 2 and K?1) to a receiver n+1; calculating, by the receiver n+1, a precoding vector of a transmitter n using the precoding vector of the transmitter n?1; and transmitting, by the receiver n+1, the precoding vector of the transmitter n to the transmitter n.

Abstract: Logarithmic Detector Amplifiers (LDAs), multiple antennas, active antennas, and multiple active antennas and receivers are provided in a variety of configurations that are synchronized to reduce or eliminate interference so at to provide, a greater range and bandwidth between wireless routers and their clients in WLAN and WAN environments.

Abstract: Embodiments for at methods, apparatus and systems for operating a voltage regulator are disclosed. One apparatus includes a switching voltage regulator, wherein the switching voltage regulator includes a series switch element, a shunt switch element, a switching controller and a switched output filter. The switching controller is configured to generate a switching voltage through controlled closing and opening of the series switch element and the shunt switch element. The switched output filter filters the switching voltage and generates a regulated output voltage, wherein the switched output filter includes a plurality of capacitors that are selectively included within the switched output filter.

Abstract: A method for interference alignment in wireless network having 3 transmitters and 3 receivers which are equipped with M antennas is provided. The method comprising: transmitting, performed by each of the 3 transmitters, a pilot signal known to the 3 receivers; estimating, performed by each of the 3 receivers, each channel from transmitter; transmitting, performed by each of the 3 receivers, feedback information to target transmitter; and determining, performed by transmitter 2 and transmitter 3, a precoding vector; wherein a degree of freedom (DoF) of a transmitter 1 is (M/2??), a DoF of the transmitter 2 or the transmitter 3 is M/2.

Abstract: A radio communication apparatus is disclosed that enables the influence of the feedback information on the channel capacity to be kept to the minimum without reducing the transmission efficiency of information by transmission of pilot symbol. In the apparatus, a delay dispersion measuring section (272) generates a delay profile using the received signal, and measures delay dispersion indicative of dispersion of delayed versions. A moving speed estimating section (274) estimates moving speed of a mobile station apparatus that transmits a pilot symbol based on the variation in reception power of the pilot symbol. An other-cell interference measuring section (276) measures other-cell interference caused by signals transmitted in cells except the cell to which the apparatus belongs.

Abstract: Included is a radio transmission system comprising a plurality of power amplifiers (PAs); a plurality of Volterra Engine (VE) linearizers corresponding to the PAs; a plurality of feedback loops corresponding to the PAs; at least one digital hybrid matrix (DHM) coupled to the VE linearizers; and an analog hybrid matrix (AHM) coupled to the PAs, wherein the feedback loops are connected to the AHM and the VE linearizers but not to the PAs to reduce the number of feedback loops. Also included is a radio system comprising a plurality of PAs; a Volterra DHM (VDHM) coupled to the PAs; a plurality of feedback loops corresponding to the PAs; and an AHM coupled to the PAs, wherein the feedback loops are connected to the AHM but not to the PAs to reduce the number of feedback loops.

Abstract: A process transmitter is configured to measure a process variable of an industrial process. The process transmitter includes a process variable sensor which senses the process variable and responsively provides a process variable sensor output. Sensor circuitry is coupled to the process variable sensor. A housing to encloses the sensor circuitry and the output circuitry. The sensor circuitry electrical couples to the housing. The sensor circuitry wirelessly communicates with the output circuitry.

Abstract: Embodiments provide systems and methods to dynamically control a radio frequency (RF) transmitter based on monitored error vector magnitude (EVM) performance. Embodiments are enabled by a feedback path that allows estimating the EVM at the output of the transmitter and controlling the transmitter, including the power amplifier (PA), accordingly. As such, the transmitter (and the PA) can be operated as close as possible to the ideal operating point that meets, based on actual conditions, a specified EVM performance and desired output power. By doing so, the overall power consumption of the transmitter is reduced.

Abstract: A receiver and a method for equalizing signals, the method includes: receiving input signals; sampling the input signals to provide oversampled samples; processing the oversampled samples to provide symbol spaced samples and to provide fractionally spaced samples that represent the oversampled samples; calculating taps of a fractionally spaced equalizer based on the symbol spaced samples; feeding the taps to the fractionally spaced equalizer; and filtering the fractionally spaced samples by the fractionally spaced equalizer to provide equalized samples.

Abstract: Broadly speaking, the embodiments disclosed herein describe an apparatus, system, and method for managing the effects of TDMA noise emitted by a communication device on an audio circuit.

Abstract: An apparatus and method of multi cell cooperation is provided. The user equipment receives transmission beam forming information from a first cooperative cell, generates serving cell feedback information and cooperative cell feedback information on the basis of the transmission beam forming information, transmits the serving cell feedback information to a serving cell, and transmits the cooperative cell feedback information to a second cooperative cell.

Abstract: Filter coefficients are generated by testing a wireless communication system using single-tone signals. While using the filter coefficients in a filter module, signal imbalance caused by a local oscillator or analog elements in a wireless communication system can be eliminated, so as to prevent the wireless communication system from being affected by the noises.

Abstract: The circuit is provided for the transmission of data amplitude modulated radio frequency signals. The circuit includes a local oscillator for generating an oscillating signal at a determined carrier frequency, a unit for shaping data pulses to supply a data amplitude modulation control signal (Vmod), and a power amplifier receiving the oscillating signal and the data amplitude modulation control signal (Vmod) for the transmission of data amplitude modulated radio frequency signals by an antenna or an antenna arrangement. The data pulse shaping unit (13) includes a pulse shaper (21) for digitally adapting the data transition edges on the basis of an incoming digital data signal (d), and a digital-analog conversion stage (26, 27) for converting a digital data signal shaped in the unit, in order to supply the data amplitude modulation control signal (Vmod) to the power amplifier.

Abstract: A data transmission method includes transmitting an encoded data signal in form of a data stream of data bursts between a transmitter and a receiver, making a decision as a function of at least one data transmission parameter as to whether an interference treatment of the data signal to be transmitted will be performed in the transmitter or in the receiver, performing the interference treatment in terms of at least one code in the transmitter, and performing the interference treatment of the data to be transmitted in terms of at least one further code in the receiver.

Abstract: A method, apparatus and computer program product are provided for conveying information regarding the antenna configuration and/or the transmission diversity scheme to a recipient, such as a mobile device. In particular, information regarding the antenna configuration and/or the transmission diversity scheme can be conveyed by masking, such as cyclic redundancy check masking, to provide information regarding the antenna configuration and/or the transmission diversity scheme. In this regard, a set of masks can be determined based upon hamming distances between the masks and bit diversities between the masks and where each of the masks within the set is associated with an antenna configuration and a transmission diversity scheme.

Abstract: An audio interface adapted to reduce a subscriber voice may receive a subscriber voice and a background noise. The subscriber voice may then be compared to the to the background noise. If the received subscriber voice is louder than the received background noise, the audio interface may output a message to the cellular telephone subscriber indicating the subscriber may reduce his speaking volume. Additionally, an audio interface may process a voice waveform that corresponds to the subscriber voice and a background waveform that corresponds to the background noise to generate a substantially opposite voice waveform and a substantially opposite background waveform respectively. The substantially opposite voice waveform and background waveform may be substantially out of phase from the voice waveform and background waveform respectively and output via one or more output ports of the audio interface.

Abstract: Methods and apparatus for reducing out of band emissions through selective resource allocation, transmit power control, or a combination thereof. A resource controller, such as a base station, can allocate uplink resources to a requesting subscriber station based in part on an expected transmit power. The base station can allocate uplink bandwidth to the subscriber station based on an expected subscriber station uplink transmit power and a frequency of a restricted emissions band. Those subscriber stations having higher expected transmit powers are allocated bandwidth further from the restricted emissions band. The subscriber station can perform complementary transmit power control based on allocated uplink resources. The subscriber station can limit a transmit power based in part on a bandwidth allocation, modulation type allocation, or some combination thereof.

Abstract: Interference that occurs during wireless communication may be managed through the use of fractional reuse and other techniques. In some aspects fractional reuse may relate to HARQ interlaces, portions of a timeslot, frequency spectrum, and spreading codes. Interference may be managed through the use of a transmit power profile and/or an attenuation profile. Interference also may be managed through the use of power management-related techniques.

Abstract: The usage capacity of a base station operating in four-branch receive diversity mode is limited to a given number of channel resources, where each channel resource corresponds to an active user. In two-branch receive diversity mode, approximately twice as many channel resources are available, but the receiver sensitivity is less than with four-branch mode. Thus, four-branch mode provides better coverage but with less usage capacity. A base station is operated in four-branch mode to provide the best coverage while usage is low. When the number of users reaches a first threshold, prior to reaching the maximum number of users, the base station transitions to two-branch mode to accommodate an anticipated increase of users above the four-branch capacity, although with reduced coverage. When usage then falls below a second threshold, the base station transitions back to four-branch mode, again providing better coverage.

Abstract: A power control method for interference alignment in wireless network having K transmitters and K receivers is provided. The method includes: receiving, performed by receiver n (n is an integer, 1?n?K?1), a power indication signal of transmitter n+1 from the transmitter n+1; determining, performed by the receiver n, power of transmitter n; and transmitting, performed by the receiver n, a power indication signal of transmitter n to the transmitter n, wherein the power of transmitter n is determined based on a residual interference of the receiver n, and the power indication signal of transmitter n indicates a minimum transmission power or a maximum transmission power of transmitter n.

Abstract: An envelope tracking power amplifier system time-aligns a supply voltage to an input signal to a power amplifier. The power supply operates in a static mode for low amplitude input signals and operates in a dynamic mode for high amplitude input signals. In the static mode, the power supply produces a substantially constant supply voltage independent of the amplitude of the input signal. In the dynamic mode the power supply produces a dynamically varying envelope tracking supply voltage based on the amplitude of the input signal. A first delay is determined based on portions of the input and output signals captured during static operation of the power supply and a second delay is determined based on portions of the input and output signals captured during dynamic operation. A delay mismatch is estimated based on a difference between the first and second delays.

Abstract: A system and method of cancelling downlink inter-channel interference between a first selected UE in one sector of a cell and a second selected UE in a second sector of said cell by using intra-eNB DL CoMP is described. UEs which are affected by ICI are identified in sectors which are adjacent to each other in the cell. A downlink CoMP operational set is formed for the identified UEs. Channel matrix blocks are estimated for the first and second selected UEs. The channel matrix blocks are representations of the channel characteristics between the first and second UE, in their respective sectors and the serving base station. The estimated channel matrix blocks are then loaded into a cross-sector channel block matrix. The inverse values of the channel matrix blocks are then calculated to form a sector specific cross-sector pre-coding matrix which is used to enable interference cancellation.

Abstract: The present invention relates to a wireless communication system and, more particularly, to a spectrum sensing method in cognitive radio communication. According to an aspect of the present invention, a method of canceling an introduced transmission signal includes generating a first signal, having an inverse phase, using a data transmission signal transmitted by a data transmission unit, adjusting a path and/or an amplitude of the first signal, and generating a first signal, having an inverse phase, using a data transmission signal transmitted by a data transmission unit, adjusting a path and/or an amplitude of the first signal, and canceling a second signal, introduced through a data receiving unit, and the first signal by the data transmission signal.

Abstract: Systems and methodologies are described that facilitate employing interference-overload indications to generate pilot strength reports that can be leveraged to mitigate reverse link interference. An affected base station can send interference-overload indications when experiencing a strong interference/jamming scenario due to reverse link transmission by an offending access terminal. The offending access terminal can monitor interference-overload indications from the affected base station (e.g., although the affected base station can be excluded from an active set of the offending access terminal) and send a pilot strength report to a serving base station in response. The serving base station can receive the interference induced pilot strength report and command the offending access terminal not to transmit on certain channel resources (e.g., time, frequency, spatial, . . . ); thus, the affected base station can use these resources to schedule transmission(s) by access terminal(s) served thereby.

Abstract: A Symbol vector for RF transmission after multiplexing onto a subset of a set of subcarriers using OFDM is transformed to the time domain. A first time domain cancellation vector is generated from a basis vector that has the same dimensionality as the symbol vector. In the frequency domain the basis vector has a substantially zero value in each of a first subset of sub-carriers of the symbol vector and in the time domain the difference between a first element of the basis vector having the highest value and a second element of the basis vector having the next highest value is maximized. The first cancellation vector is subtracted from the symbol vector to produce modified symbol vector having reduced Peak-to-Average Power Ratio (PAPR). A second cancellation vector is generated using the modified symbol vector and is used to produce a second modified symbol vector having reduced PAPR.

Abstract: Provided are a packet transmission scheduling method in a wireless network and a packet transmission method using the same. The packet transmission scheduling method, includes storing location information and a path loss exponent of each node on a multiplexing path; calculating a Signal-to-Interference and Noise Ratio (SINR) between nodes on a predetermined path based on the stored location information; when the calculated SINR exceeds a threshold, forming the paths as a path table; and scheduling packet transmission based on the formed path table.

Abstract: A communication device according to an embodiment of the present invention includes a communication antenna that receives a transmission signal where a spectrum spread signal subjected to a spectrum spread is modulated; an intermediate frequency converting unit that converts the transmission signal received by the communication antenna into an intermediate frequency signal having a predetermined frequency; an analog to digital converting unit that discretizes the intermediate frequency signal and outputs a discretization signal; a noise removing unit that detects a noise other than a normal thermal noise included in the discretization signal and removes the detected noise from the discretization signal; and a demodulating unit that demodulates the spectrum spread signal, based on the discretization signal that is output from the noise removing unit.

Abstract: A wireless communication device according to the present invention includes high-frequency circuits 20 to 22 that convert an input signal into a high-frequency signal; a power detection circuit 40 that detects power of the high-frequency signal output from the high-frequency circuits 20 to 22; a common correction circuit 12 that performs a common correction on the signal output to the high-frequency circuits 20 to 22 to reduce local leaks occurring in the high-frequency circuits 20 to 22, according to the power of at least one high-frequency signal detected by the power detection unit 40; and an individual correction circuit 11 that performs a correction for each signal output to the high-frequency circuits 20 to 22 to reduce local leaks occurring in the high-frequency circuits 20 to 22, according to the power of each high-frequency signal detected by the power detection unit 40.

Abstract: A method and apparatus for a non-linear adaptive scheme for transmit out of band emission cancellation is provided. Embodiments disclosed herein provide a method for removing unwanted transmitter emissions from a composite received signal. The method performs the steps of: extracting the I and Q samples from a modulator output; inputting the I and Q samples to a non-linear filter; applying weights to the non-linear filter outputs, combining the non-linear filter outputs to generate a broadband emission estimate; selecting a portion of a transmit emission in a desired portion of a receive band; subtracting an output of the non-linear filter from a composite signal; and feeding back a residual error to the non-linear filter; adapting the non-linear filter iteratively.

Abstract: A method, system and device are provided for avoiding in-device coexistence interference between different radio technologies deployed in adjacent bands on the same device by providing preferred frequency solutions for the in-device coexistence system.

Abstract: The present invention is provided to perform uplink scheduling of a mobile station. In order to perform the uplink scheduling of the mobile station located in a service cell, a base station receives a plurality of interference amounts each corresponding to a plurality of frequency bands associated with an uplink in at least one adjacent cell corresponding to the mobile station from the base station of at least one adjacent cell, respectively, and calculates a plurality of interference values each corresponding to the plurality of frequency bands by using the plurality of interference amounts each corresponding to at least one adjacent cell. In addition, the base station generates scheduling control information corresponding to the mobile station by using the plurality of interference values and transmits the scheduling control information to the mobile station.

Abstract: Disclosed is a transmitter for a communication system. The transmitter comprises a sidelobe suppression module configured to apply a suppression matrix to an input vector comprising symbols to be transmitted by the transmitter; a modulation module configured to modulate the precoded vector to a time-domain symbol using a plurality of subcarriers, each symbol in the precoded vector having a corresponding subcarrier; and a digital-to-analog conversion module configured to convert the time-domain symbol to an analog waveform for transmission. The suppression matrix is constructed such that emissions at one or more predetermined suppression distances lying outside a frequency band defined by the subcarriers are set to zero according to a predetermined emission model.

Abstract: A radio communication device reproduces a carrier signal by eliminating phase noise from a carrier phase signal detected from a received baseband signal. Herein, a filtering characteristic having a default value is adopted to eliminate phase noise from the carrier phase signal with respect to a firstly received baseband signal. Integrated phase noise characteristics are calculated by adding a transmission-side phase noise characteristic, which is extracted from a radio frame demodulated from the carrier signal, to a predetermined reception-side phase noise characteristic. An optimum filtering characteristic is selected through comparison between a threshold and integrated phase noise characteristics. The selected filtering characteristic is adopted to eliminate a noise component from the carrier phase signal with respect to a subsequent baseband signal.

Abstract: A precoding method and apparatus are disclosed. The corresponding method includes: constructing a Lagrange function according to a precoding matrix, transmit power, a receive filter matrix and a weighting matrix, and obtaining a Lagrange multiplier by using the Lagrange function; updating the precoding matrix according to the Lagrange multiplier to obtain an iterative precoding matrix and an iterative receive filter matrix; obtaining an iterative Lagrange multiplier according to the iterative precoding matrix, the transmit power, the iterative receive filter matrix and the weighting matrix, and repeating the above steps in an iterative manner of updating the iterative precoding matrix according to the iterative Lagrange multiplier till the iterative precoding matrix converges to a threshold; and precoding information to be transmitted according to the iterative precoding matrix converging to the threshold.

Abstract: A calibration system may be provided for calibrating wireless communications circuitry in an electronic device during manufacturing. The calibration system may include data acquisition equipment for receiving an amplitude-modulated calibration signal from the electronic device. The calibration system may include calibration computing equipment for extracting pre-distortion coefficients from the amplitude-modulated calibration signal. The calibration computing equipment may be configured to detect a bulk phase drift in the amplitude-modulated calibration signal. The calibration computing equipment may be configured to remove the bulk phase drift from the amplitude-modulated calibration signal. The wireless communications circuitry may include a power amplifier that distorts a signal generated by the wireless communications circuitry. The wireless communications circuitry may include a pre-distortion compensator for countering the distortion.

Abstract: The present disclosure generally relates to predistortion that compensates for non-linearity of a power amplifier as well as short-term and long-term memory effects of the power amplifier. In one embodiment, a transmitter includes a power amplifier that amplifies a power amplifier input signal to provide a power amplifier output signal, a predistortion sub-system that effects predistortion of the power amplifier input signal to compensate for non-linearity of the power amplifier and memory effects of the power amplifier, and a adaptation sub-system that adaptively configures the predistortion sub-system. The predistortion sub-system includes a memory-less predistortion component that compensates for the non-linearity of the power amplifier, a Finite Impulse Response (FIR) filter that compensates for short-term memory effects of the power amplifier, and an Infinite Impulse Response (IIR) filter that compensates for long-term memory effects of the power amplifier.

Abstract: In one embodiment, a non-linear power amplifier generates an amplified output signal based on a pre-distorted signal generated by a digital pre-distorter based on an input signal. A feedback path generates a feedback waveform based on the amplified output signal. The feedback waveform is aligned in time with the input signal at the waveform level to identify a corresponding reference waveform. The feedback waveform and the corresponding reference waveform are both divided into a plurality of sub-waveforms. Each feedback sub-waveform is independently aligned in phase with its corresponding reference sub-waveform. The resulting plurality of phase-aligned feedback sub-waveforms are then combined to form a hybrid-aligned waveform that is compared to the reference waveform to adaptively update the digital pre-distorter.

Abstract: A DC offset estimator and removal circuit removes the DC offsets for each of the I and Q signal components in a received signal. A gain imbalance estimator and compensator circuit estimates and compensates for gain imbalances within the I and Q signal components. A phase imbalance estimator and compensator circuit estimates and compensates for phase imbalances within the I and Q signal components to produce a communications signal that is compensated for received DC offsets and gain and phase imbalances within the I and Q signal components.