Nokia Networks Oy

Nokia Corporation

Nokia Telecommunications Oy

Toni Neffling

Jari Pekkarinen

Esa Tapani Tiirola

Juha Ylitalo

Peter Muszynski

Olli Tapio

The invention relates to a linearization method for an RF amplifier and an arrangement implementing the method. A difference between an output signal of the amplifier and an unpredistorted input signal supplied to the amplifier is formed from baseband, quadrature components by means of a complex LMS algorithm in adaptation means. On the basis of the signal difference, the non-linearity of the amplifier is adaptively corrected before a quadrature modulator by changing the values of the complex quadrature components of the baseband signal by means of digital predistortion coefficients retrieved from a memory.

Linearization method for amplifier, and amplifier arrangement

A method of setting up a linearizing circuit such as a linear power amplifier is described. According to the method, an input signal is supplied at a low, starting power level and is lowly increased during a set-up until it attains an operational level for normal use. The advantage of this is that pilot tone used in the linearizing circuit can be readily detected during set-up because its amplitude is above that of the low, starting power level of the input signal. A feed-forward linearizing system and a transmission system utilizing the technique are described.

Set-up method for a linearizing circuit

The invention relates to a control method and a control arrangement which comprises a feedforward power amplifier (,), which receives and amplifies a signal and which on amplifying the signal causes non-linearities to the signal. The control arrangement also comprises adjusting members (,) and adaptation means (,), which form an adaptation factor and control the operation of the adjusting means (,) by means of the adaptation factor by adapting the amplitudes and phases of signal propagating along different signal paths to one another. The control arrangement further comprises control means (,), which produce information of the gain required by the power amplifier (,), said control means (,) ordering the adaptation means (,) to adjust the adaptation factor in advance on the basis of the received information to correspond to the gain of the power amplifier (,), which enables adaptation of the signal also when the input power level changes rapidly.

Control method and control arrangement

A test method in an RF communication system. In the communication system, at least one RF communication channel lies about a known carrier frequency in an RF communication band. According to the method, a diagnostic signal is introduced into a circuit to be tested, such as a linear power amplifier, the diagnostic signal having an RF diagnostic frequency lying within the communication band. The diagnostic signal is down converted to an intermediate frequency for diagnostic purposes so that DSP is simplified. The diagnostic frequency is selected based on the known carrier frequency of the communication channel so that the communication channel is not down converted as an image band with the diagnostic signal.

Testing in an RF communication system

The invention relates to a linearization method and an amplifier arrangement, in which a signal to be amplified is predistorted by utlilizing digital predistortion information stored in the memory of a predistortion controller. Predistortion means predistort the signal to be amplified in its analogue form, the predistortion is adapted at least to the signal to be amplified, the predistorion information stored in the memory of the controller correspond to the variables of polar coordinates, such as phase and amplitude, and the phase and amplitude of the signal to be amplified are distorted in the predistortion in accordance with the predistortion information located in the memory of the controller.

Linearization method and amplifier arrangement

The invention relates to an adaptation method and amplifier arrangement, which comprises feedforward amplifying means (,) which amplify a signal entering the arrangement, and adjusting means (,) which use complex factors &agr; and &bgr;, which are adapted in order to adjust the phase and amplitude of the input signal to the amplifier arrangement. The amplifier arrangement also comprises attenuation means (,) which attenuate the signal amplified by the amplifier (,), means (,) which subtract the attenuated signal from the adapted signal, adjusting means (,) which receive part of the signal entering the arrangement for adaptation by factor a, which is adapted partly by the signal obtained from the adapted signal. Furthermore, the amplifier arrangement comprises means (,) which are connected to the outgoing end of the amplifier (,) and form a predetermined signal, adders (,) which add the predetermined signal to the signal amplified by the amplifying means (,), means (,) which form a conjugate signal of the adapted signal and multiply the conjugate signal by the predetermined signal and control adaptation of factor &bgr; by means of the signal obtained as a result of multiplication.

Adaptation method and amplifier arrangement

The invention relates to a RAKE receiver of a CDMA system using IRC, the receiver receiving a radio signal by using at least two antenna branches. In accordance with the invention a RAKE finger comprises: a weighting coefficient part for forming weighting coefficients maximizing the Signal-to-Interference-and-Noise Ratio for each antenna branch; a multiplier for multiplying a pilot part, despread by a despreader in each antenna branch, by a weighting coefficient; a multiplier for multiplying a data part, despread by a despreader in each antenna branch, by a weighting coefficient; an antenna branch summer for combining the despread pilot parts, received via the separate antenna branches and multiplied by the weighting coefficient, to one pilot signal; an antenna branch summer for combining the despread data parts, received via the separate antenna branches and multiplied by the weighting coefficient, to one data signal. In addition, the receiver comprises a RAKE finger summer for combining the data signals of the RAKE fingers operating by different delays to a sum data signal representing the received bits.

Growing community of inventors

Espoo, Finland

Toni Neffling