Nokia Solutions and Networks Oy

Nokia Solutions and Networks Gmbh & Co. Kg

Nokia Technologies Oy

Christian Reichl

Shavantha Kularatna

Bjoern Jelonnek

Rene Roeschke

Alan Pereira

Glenn Schedeen

Sandeep Mehta

Marko Fleischer

Jan Hellmann

Tian He

Michael Kronwald

Norbert Hueller

Aki Heikki Jalmari Korhonen

Aki Korhonen

A method comprising determining a plurality of digital pre-distortion engines, determining signals for the pre-distortion engines, determining terms for a matrix and filter the matrix, based on the filtered matrix, determining correlation matrixes, obtaining pre-distorted signals from the digital pre-distortion engines, wherein the pre-distorted signals are pre-distorted based on the determined correlation matrixes, and combining the pre-distorted signals to a combined pre-distorted signal.

Interference mitigation with multi-band digital pre-distortion

Various communication devices may benefit from the appropriate use of modeling techniques. For example, devices that include components that may be driven into non-linear ranges of operation may benefit from low complexity non-linear modelling techniques. Such devices may be used, for example, in wireless communication systems. A method can include obtaining a sample of a signal representative of power consumed by a device while the device is operating in a non-linear range while being driven according to a driving signal. The method can also include computing a correction to the driving signal based on the sample. The correction can be calculated based on a plurality of non-overlapped non-linear sections corresponding to a response of the device. The method can further include applying the correction to adjust the driving signal. The correction can be configured to adjust the power to a desired value of power.

Low complexity non-linear modelling techniques for wireless technologies

The present invention addresses method, apparatus and computer program product for stabilization of the direct learning algorithm for wideband signals. Thereby, a signal to be amplified is input to a pre-distorter provided for compensating for non-linearity of the power amplifier, and the pre-distorted output signal from the pre-distorter is forwarded to the power amplifier. Parameters of the pre-distorter are adapted based on an error between the linearized signal output from the power amplifier and the signal to be amplified using an adaptive direct learning algorithm, and the linear system of equations formed by the direct learning algorithm are solved using a conjugate gradient algorithm, wherein, once per direct learning algorithm adaptation, at least one of the initial residual and the initial direction of the conjugate gradient algorithm are set based on the result of the previous adaptation.

Stabilization of direct learning algorithm for wideband signals

The present invention addresses method, apparatus and computer program product for controlling a Direct Learning Algorithm. Thereby, a power amplifier operating in a non-linear state is controlled. A signal to be amplified is input to a pre-distorter provided for compensating for non-linearity of the power amplifier. The pre-distorted output signal is forwarded from the pre-distorter to the power amplifier. Parameters of the pre-distorter are adapted in plural steps based on an error between a linearized signal output from the power amplifier and the signal to be amplified using an adaptive direct learning algorithm. It is detected whether the error diverges; and adapting of the parameters of the pre-distorter is stopped when it is determined that the error is diverging.

Controlling mechanism for a direct learning algorithm

The present invention addresses apparatuses, methods and computer program product for providing improved distance to fault measurement for voltage standing wave ratio (VSWR) on antenna line in networks. An embodiment of the present invention comprises the steps of transmitting a signal to a line to be tested, capturing a forward signal of the signal, capturing a reverse signal of the signal, separating the reflection of the signal in time domain via cross correlation of the forward signal and the reverse signal, and detecting a distance to fault in the line by searching and processing maximum peak position of the captured and separated signals.

Distance to VSWR fault measurement

Enhancing the intermodulation performance of an RF power amplifier by determining a coarse time delay represented by an integer TI; determining a reference point for a transmitted signal waveform of the RF power amplifier; shifting the waveform by a set of offsets including a plurality of non-integer fractional steps; correlating the transmitted signal waveform with a feedback signal waveform to obtain a respective correlation value for each of corresponding fractional steps; obtaining an accurate fractional delay value by selecting a fractional step having a highest respective correlation value; applying the obtained correct fractional delay value to the transmitted signal waveform to provide a compensated transmitted signal waveform and combining the compensated transmitted signal waveform with the feedback signal waveform to reduce at least one intermodulation product of the RF power amplifier.

Using fractional delay computations to improve intermodulation performance

At a current time, a current intermodulation content of a predistortion system is determined. An intermodulation ratio is determined using the current intermodulation content and a previous intermodulation content for the predistortion system. The previous intermodulation content is determined at a time previous to the current time. The determined intermodulation ratio is compared with stored intermodulation ratios. A warning is communicated in response to the comparing indicating the predistortion system is unhealthy. Apparatus and computer program products are also disclosed.

Monitoring health of a predistortion system

Enhancing the intermodulation performance of an RF power amplifier by determining a coarse time delay represented by an integer T1; determining a reference point for a transmitted signal waveform of the RF power amplifier; shifting the waveform by a set of offsets comprising a plurality of non-integer fractional steps from (T1&#x2212;Xd) to (T1+Xd) where T1 is the integer and Xd is a non-integer fractional step size value for defining fractional steps about the integer T1 such that the non-integer fractional steps progress in a positive direction as well as a negative direction; correlating the transmitted signal waveform with a feedback signal waveform to obtain a respective correlation value for each of corresponding fractional steps; obtaining an accurate fractional delay value by selecting a fractional step having a highest respective correlation value; applying the obtained correct fractional delay value to the transmitted signal waveform to provide a compensated transmitted signal waveform, and combining the compensated transmitted signal waveform with the feedback signal waveform to reduce at least one intermodulation product of the RF power amplifier.

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Hirschau, Germany

Christian Reichl