A distortion compensating apparatus for compensating for a distortion of a transmission power amplifier. A delay time decision unit calculates the correlation between a transmission signal and a feedback signal fed back from the output side of the transmission power amplifier while varying phase difference between both signals, and decides the total delay time caused in the transmission power amplifier and a feedback loop on the basis of the phase difference in which the correlation is the maximum. A delay unit delays the transmission signal before a distortion compensation processing by the total delay time, and inputs the delayed signal into a distortion compensating apparatus arithmetic unit, which calculates and stores a distortion compensation coefficient on the basis of the transmission signal and the feedback signal fed back from the output side of the transmission power amplifier. A pre-distortion unit applies a distortion compensation processing to the transmission signal by using the distortion compensation coefficient.

Distortion compensating apparatus

A method for calibrating a base station comprising a plurality of antennas is provided First correction information is received from a system module, the correction information determined from first calibration of the base station Signals are received at a radio frequency module from at least one antenna of the base station Second correction information is determined on the basis of the received signals and the first correction information.

Base station calibration

A remote radio head unit (RRU) system for multiple operating frequency bands, multi-channels, driven by a single or more wide band power amplifiers. More specifically, the present invention enables multiple-bands RRU to use fewer power amplifers in order to reduce size and cost of the multi-band RRU. The present invention is based on the method of using duplexers and/or interference cancellation system technique to increase the isolation between the transmitter signal and receiver signal of the RRU.

Remote radio head unit system with wideband power amplifier and method

Apparatus and methods for envelope tracking calibration are provided. In one embodiment, a method of calibrating an envelope tracker having an envelope shaping table generated at a desired gain compression of a power amplifier is provided. The method includes generating a supply voltage for the power amplifier using the envelope tracker, operating the supply voltage of the power amplifier at a first voltage level associated with substantially no gain compression of the power amplifier, and measuring an output power of the power amplifier at the first voltage level. The method further includes decreasing a voltage level of the supply voltage one or more times and measuring the output power at each voltage level, determining a second voltage level of the power amplifier associated with a gain compression equal to about that of the desired gain compression, and calibrating the envelope tracker based on the determination.

Apparatus and methods for envelope tracking calibration

A method for calibrating the output power of a mobile terminal using at least a second order curve fit to describe a power amplifier gain (PAG) setting versus output power characteristic of a power amplifier in a transmitter of the mobile terminal is provided. For each of an upper-band frequency, a mid-band frequency, and a lower-band frequency of a frequency band, multiple measurements of the output power of the mobile terminal are made corresponding to multiple values of the PAG setting, and a curve fit is performed, thereby calculating coefficients defining a polynomial describing the PAG setting versus output power characteristic. Using the polynomials describing the PAG setting versus output power characteristic of the power amplifier for each of the upper-band, mid-band, and lower-band frequencies, values of the PAG setting are determined for each desired output power level for each desired frequency within the frequency band.

N-th order curve fit for power calibration in a mobile terminal

In an RF amplifier with input signal dependent power supply voltage control, a timing controller (432) is used to determine the delay of the main signal path (from node N via 411, 40 and 431 to 432) in a first step, while a fixed value from switch (421) is applied to the power supply control path, and to determine the delay of the power supply control path (from node N via 421, 422, 423, 40 and 431 to 432) in a second step, while the main amplifier (40) receives at its input a fixed value from switch (411). In a third step, a possible difference between these delays is corrected (423) by adjusting the delay of at least one of the two paths. After this calibration, the switches (411,421) couple the transmission signal to be amplified to both paths.

Delay controller and delay control method

A distortion correction control apparatus is for compensating for burst distortion of a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes holding means for storing a distortion correction coefficient having reverse characteristics to the burst distortion; means for multiplying the distortion correction coefficient read out from the holding means by the input signal or adding the distortion correction coefficient read out from the holding means to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and update means for updating, based on the input signal, the distortion correction coefficient of the last time, and a signal fed back as an output signal of the transmission amplifier, the distortion correction coefficient by an adaptive algorithm, and inputting the updated distortion correction coefficient to the holding means.

Distortion compensation controller and distortion compensation control method

A power amplifier apparatus that includes a processor that performs a first distortion compensation processing on an input signal using a distortion compensation coefficient to obtain a first signal and an amplifier that amplifies the first signal The processor performs a second distortion compensation processing the amplified signal using the distortion compensation coefficient to obtain a second signal and updates the distortion compensation coefficient to enable convergence between the first signal and the second signal

Power amplifier apparatus, distortion compensation coefficient updating method, and transmission apparatus

A wireless apparatus includes: an A/D converter which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of the A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on the in-phase and quadrature signals output from the digital quadrature demodulation unit, detects a time difference error between the sample timing of the in-phase signal component and the sample timing of the quadrature signal component.

Wireless apparatus and signal processing method

A distortion compensation apparatus includes an amplifying unit, a plurality of distortion compensation coefficient storage units, a first address generating unit, a second address generating unit, and a distortion compensating unit. The amplifying unit amplifies an input signal. A plurality of distortion compensation coefficient storage units store the distortion compensation coefficients for compensating for the distortion of the amplifying unit by being associated with two different addresses. The first address generating unit generates a first address based on the current input signal. The second address generating unit generates a second address different from the first address based on the previous input signal. The distortion compensating unit obtains the distortion compensation coefficient corresponding to a combination of the first and second addresses from each of the distortion compensation coefficient storage units and performs a pre-distortion processing for the current input signal to the amplifying unit using the obtained distortion compensation coefficient.

Hiroyoshi Ishikawa

Papers

Delay controller and delay control method

Distortion compensation controller and distortion compensation control method

Power amplifier apparatus, distortion compensation coefficient updating method, and transmission apparatus

Wireless apparatus and signal processing method

Distortion compensation apparatus, transmitter, and distortion compensation method