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

Gleichstrom-offsetkompensationsverfahren und -einrichtung

A peak suppression apparatus includes an acquiring unit that acquires a first signal represented by an amplitude waveform of a multicarrier signal, a generator that generates a second signal represented by a waveform sequentially connecting a plurality of peak points adjacent to one another in the first signal as a peak detection signal for the multicarrier signal, a detector that detects a peak value and a peak timing of the multicarrier signal by using the peak detection signal, and a suppressing unit that suppresses a peak of the multicarrier signal based on the peak value and the peak timing.

Peak suppression apparatus

Fully connected hybrid antenna arrays (FC-HA) are attractive, low-complexity alternatives to the fully digital array architecture. However, the sub-array architecture performance is limited by reduced beamforming gain because of array partitioning. In this study, we provide a theoretical analysis of the connection between a wideband digital predistorter (DPD) and its equivalent for a fully connected antenna array (AA). Then, we propose new hardware-efficient band-oriented architecture by moving all AA-specific DPD calculations into the analog radio frequency site. To our knowledge, this is the first band-oriented DPD architecture for FC-HA. In the proposed DPD, the unified digital cores are common for all power amplifiers (PAs) in the array. This enables a set of PAs to be linearized with a single, multi-core DPD. The performances of the proposed band-oriented DPD were evaluated with the help of computer simulation. The simulation results demonstrate that both the in-band and the out-of-band intermodulation distortion for all PAs in the array can be successively suppressed with a single multi-core DPD regardless of the individual beam’s directions. Unlike current all-digital state-of-the-art solutions, the proposed band-oriented DPD has a significantly low digital hardware complexity because of the digital core unification, thus reducing its power consumption requirement.

Band-Oriented Predistorter for Fully Connected Hybrid Antenna Arrays

PROBLEM TO BE SOLVED: To provide a wireless communication apparatus capable of uniforming the quality of a transmission signal even when peak is suppressed to use a power amplifier in a saturation domain having high power efficiency. SOLUTION: A subtractor 110 and a filter portion 120 are provided on the latter stage of a hard clip portion 100 as a conventional hard clip processing unit for limiting amplitude at a predetermined threshold. A transmission signal is inputted into the hard clip portion 100, the subtractor 110 and an adder 130. The subtractor 110 subtracts a transmission signal before amplitude limitation from a transmission signal subjected to amplitude limitation by the hard clip portion 100, thereby extracting a peak suppressing signal. The filter portion 120 performs filter processing so that the peak suppressing signal extracted by the subtractor 110 may have flat frequency characteristics. Finally, the adder 130 adds the peak suppressing signal having flat frequency characteristics to the transmission signal before amplitude limitation. COPYRIGHT: (C)2010,JPO&INPIT

Hiroyoshi Ishikawa

Papers

Gleichstrom-offsetkompensationsverfahren und -einrichtung

Peak suppression apparatus

Band-Oriented Predistorter for Fully Connected Hybrid Antenna Arrays

Peak suppressing apparatus, peak suppressing method, and wireless communication apparatus