Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Gerald Ulbricht

Heinz Gerhaeuser

Gerd Kilian

Rainer Perthold

Reiner Retkowski

Eberhard Gamm

Christopher Laske

Josef Bernhard

Albert Heuberger

Heinz Gerhauser

Michael Schlicht

Ralph Oppelt

Stefan Ereth

Tobias Dräger

Alexej Jarresch

Günter Rohmer

Michael Kamper

Felix Auer

Martin Keppeler

Embodiments of the present invention provide a participant of a wireless communication system, wherein the participant includes a transmission and/or reception unit and an antenna array connected to the transmission and/or reception means, wherein the antenna array includes a magnetic antenna with a loop discontinued once or multiple times.

Participant of a communication system with a magnetic antenna

Embodiments of the present invention provide an antenna arrangement including a magnetic antenna and a tuning element. The magnetic antenna includes a loop interrupted one or several times and a tuning element for tuning the magnetic antenna. The tuning element is configured to provide a tuning signal (e.g., control signal) for tuning the magnetic antenna, and to control the tuning element with the tuning signal to tune the magnetic antenna.

Generating a tuning signal for tuning a magnetic antenna

An apparatus for generating a correction signal for linearizing an output signal of a non-linear element includes a correction signal generator. The correction signal generator is configured to generate a correction signal on the basis of a superposition of a digital reference signal and a superposed output signal. The superposed output signal is based on a superposition of the output signal and an analog reference signal.

Apparatus for generating a correction signal

An I/Q modulator used for processing an I/Q signal to obtain a predistorted output signal. The I/Q signal has an I component and a Q component, and comprises a predistorter for predistorting, with a predistortion signal, a carrier signal, which comprises a first subcomponent and a second subcomponent that is substantially orthogonal to the first subcomponent, to obtain first and second predistorted subcomponents of the carrier signal. The predistortion signal depends on the I and Q components. A first multiplier multiples the I component by the first predistorted subcomponent to obtain a multiplied I component. A second multiplier multiples the Q component by the second predistorted subcomponent to obtain a multiplied Q component. An adder adds the multiplied I component and the negative multiplied Q component to obtain the predistorted output signal. Thus, a simplification of the I/Q modulator and a reduction in the number of necessary multipliers is achieved.

I/Q modulator with carrier predistortion

An I/Q modulator processes a time-discrete I/Q signal comprising an I component and a Q component. The I/Q signal is based on a sampling frequency which is equal to four times a carrier frequency of a carrier signal onto which the I/Q signal is modulated. A predistorter of the modulator predistort the I and components with a predistortion signal, which depends on the I and Q components, so as to form a predistorted I component and, in temporal alternation therewith, a predistorted Q components. An adjuster of the modulator adjusts the signs of the predistorted I and Q components so that two temporally successive predistorted components have a first sign and two additional successive predistorted components, which follow the first-mentioned components in time, have a second sign which is the inverse of the first sign, so as to produce therefrom an output signal at an output of the modulator.

Digital I/Q modulator having a predistortion

In a method for estimating a non-linear characteristic of an amplifier, an input signal is provided, a reference signal is determined based on the power of the input signal, the input signal is amplified using said amplifier in order to produce an amplified signal, a measurement signal is determined based on the power of the amplified signal and respective samples of the measurement signal are associated with respective samples of the reference signal. A gain value of said amplifier for each sample is determined from the respective samples of the reference signal and the measurement signal. An operating range of the amplifier is divided into a plurality of power sections and an averaged gain value is produced for each power section. Thereafter, a measure of the deviation of the gain values associated with a power section from said averaged gain value is determined. Then, averaged gain values are rejected which have a measure of the deviation which exceeds a predetermined threshold. Finally, an interpolation is performed using averaged gain values which have not been rejected in order to produce an estimation of said non-linear characteristic of said amplifier.

System for estimating a non-linear characteristic of an amplifier

A circuit for pre-distorting an input signal v to be transmitted via a power amplifier having a non-linear transmission characteristic to produce a pre-distorted input signal y comprises an estimator ( ) for determining an estimation signal ( ) based on the power of said input signal v. A look-up table ( ) is provided for storing complex pre-distortion coefficients B and A which depend on the power of the input Signal v and the non-linear transmission characteristic of the power amplifier determined in advance. For B , the relation B &equals;A &minus;K, K being a constant with 0<K <2 applies, and A and A are the real and imaginary parts of a complex pre-distortion function which provides a pre-distortion of the input signal v such that the distortion introduced by the non-linear transmission characteristic of the power amplifier is substantially compensated according to magnitude and phase. Finally, a pre-distorter is provided in order to pre-distort the input signal according to y&equals;v&middot;(K&plus;B &plus;jA ).

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Röthenbach, Germany

Gerald Ulbricht