Nokia Solutions and Networks Oy

Nokia Corporation

Nortel Networks Corporation

Nokia Solutions and Networks Gmbh & Co. Kg

Nokia Technologies Oy

Shavantha Kularatna

Christian Reichl

Peter Anthony Barany

Bjoern Jelonnek

Tian He

Chandra Sekhar Bontu

Shamim Akbar Rahman

Rene Roeschke

Chad Young

Basavaraj Patil

Peter Y Novak

Shkumbin Hamiti

Tuomas Niemela

Eric Johnson

Ramasamy Gopalan

Yonghai Gu

Jacob Edward Longwell

Sandeep Mehta

Glenn Schedeen

Alan Pereira

Stefano M Faccin

Rene Waraputra Purnadi

Markus Isomäki

Karl D Mann

Yousuf Saifullah

Raino Lintulampi

Rayadurgam Ravikanth

Atte Länsisalmi

Adrien Comeau

Risto Mononen

Pekka Mottonen

Sreenivas Addagatla

Gabriel Ramos

Timothy L Moran

Pekka Korja

Raquel Sanchez

Sanna Mäenpää

Kaiser Chen

Artur Drozdz

Yared Melese

N Gamini Senarath

Heikki P&auml;ivike

Kari Jyrkk&auml;

Aki Korhonen

Aki Heikki Jalmari Korhonen

Basavarai Patil

Syed Hossain

Arthur Drozdz

This specification relates to digital pre-distortion of signals before power amplification during the transmission of a signal. A method comprising: receiving an input signal 1and 2subband signals associated with 1and 2centre frequencies; applying a pre-distortion to the input signal to generate a pre-distorted signal, the pre-distortion applying an inverse to a power amplification model associated with a power amplifier; and outputting the pre-distorted signal for power amplification. The power amplification model or the inverse to the power amplification model comprises a first plurality of terms and a second plurality of terms. Each of the 1and 2plurality of terms comprising a product of a complex coefficient, a power factor, and other factors depending on if it is 1or 2plurality of terms.

Dual-band digital pre-distortion system and method

As solution for predistorting a signal is presented. The solution comprises receiving () as an input a signal comprising at least two signal components on a different band, sampling () the input signal comprising linear terms, composite non-linear terms causing intermodulation outside Nyquist band of the input signal and further non-linear terms causing intermodulation inside the Nyquist band, the further non-linear terms comprising multi-band terms. Oversampling () by a given factor is applied to the signal in a first predistortion circuit for processing the linear terms and composite non-linear terms causing intermodulation outside Nyquist band; processing () the input signal without oversampling in a second predistortion circuit in parallel with the first predistortion circuit for the further non-linear terms. The rates of the output signals of the predistortion circuits are matched (), combined and filtered ().

Predistortion method

A method, apparatus and computer program product is disclosed. The apparatus may comprise means for providing a model for a system for mitigating unwanted effects in a received signal and a means for determining a first curve, a, by performing autocorrelation of the model. The apparatus may also comprise means for determining a second curve, Xcorr, by performing cross-correlation of the model and a received signal comprising unwanted components due to first and second sources and means for estimating first and second delays associated with respective first and second sources based on the first and second curves, a, Xcorr. The unwanted effects in the received signal may be PIM products/components, but the disclosure is not limited to PIM alone, and embodiments may be used to mitigate or compute peaks in any interfering scenario where peaks may be hidden.

Estimating delays

An apparatus is disclosed, comprising means for providing two or more amplifiers for amplifying signals in two or more respective frequency bands, receiving a composite signal comprising first and second predistorted input signals in first and second frequency bands and filtering the composite signal to provide (i) the first predistorted signal for input to a first amplifier of the two or more amplifiers for producing an amplified first output signal and (ii) the second predistorted signal for input to a second amplifier of the two or more amplifiers for producing an amplified second output signal. The apparatus may also comprise means for routing, at non-overlapping times, the first and second output signals to a common feedback path and for linearizing received first and second input signals based on the respective first and second output signals received on the common feedback path.

Radio apparatus

An apparatus is disclosed, comprising means for determining a noise floor for a radio frequency (RF) system. The apparatus may also comprise means for determining a Passive InterModulation (PIM) value of a component of the RF system contributing as a source of PIM; determining that a passive intermodulation (PIM) cancellation system should be enabled if the PIM value is above a predetermined threshold from the noise floor. The apparatus may also comprise means for determining that the PIM cancellation system should be disabled if the PIM value is at or below the predetermined threshold.

PIM cancellation

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

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.

The method and system provides a data packet encapsulated with protocol data according to an embodiment of the invention. A data packet for communication may be associated with a TLLI and a NSAPI identifying a communications path between a BSS and a SGSN. The method and system provides a BVC associated with the BSS and the SGSN and a NSE that provides communication service to the BVC over NS-VC. The BVC, NSE and NS-VC may be associated with the TLLI and NSAPI. The encapsulated protocol data comprises UDP and IP. UDP provides UDP ports associated with NS-VC. The UDP ports identified as data designated as either real time or non-real time services. IP provides an IP address identifying the NSE providing service to the BVC. The data packet encapsulated with UDP and IP provides for more efficient, flexible and reliable communications between a BSS and a SGSN.

Method and system for communicating data between a mobile communications architecture and a packet switched architecture

The present invention relates to a relocation method, system and network element for changing a serving radio resource control entity After an initial operating state in which a user equipment () has radio links with a serving network element () and a drift network element () supporting said serving network element () with a wireless connection, the serving network element () transmits a relocation-specific information to a target network element (). Based on the relocation-specific information, the target network element () establishes a link to the drift network element (), such that the drift network element () can receive user traffic from both the serving network element () and the target network element (). Then, the radio resource control is relocated to the target network element (). The relocation-specific information may comprise an identifier or a list of identifiers of drift network elements. Thus, existing soft handover techniques can be enhanced by allowing a user plane connection to be maintained with drift network elements. Thereby, any amount of drift network elements can be kept, with improved radio performance as a consequence.

Relocation method, system and network element

Growing community of inventors

Flower Mound, TX, United States of America

Shavantha Kularatna