Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Radio Frequency Power Amplifiers: Behavioral Modeling, Parameter Reduction, and Digital Predistortion
KTH, School of Electrical Engineering (EES), Signal Processing.
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This work considers behavioral modeling, parameter-reduction, and digital predistortion of radio frequency power amplifiers. Due to the use of modern digital modulation methods, contemporary power amplifiers are frequently subjected to signals characterized by considerable bandwidths and fast changing envelopes. As a result, traditional quasi-memoryless amplitudeto-amplitude (AM/AM) and amplitude-to-phase (AM/PM) characteristics are no longer sufficient to describe and model the behavior of power amplifiers; neither can they be successfully used for linearization. In this thesis, sampled input and output data are used for identification and validation of several block structure models with memory. The time-discrete Volterra model, the Wiener model, the Hammerstein model, and the radial-basis function neural network are all identified and compared with respect to in-band and out-of-band errors. Two different signal types (multitones and noise), with different powers, peak-to-average ratios, and bandwidths have been used as inputs to the amplifier. Furthermore, two different power amplifiers were investigated, one designed for third generation mobile telecommunication systems and one for second generation systems.

A stepped three-tone measurement technique based on digitally modulated baseband signals is also presented. The third-order Volterra kernel parameters were determined from identified intermodulation products. The symmetry properties of the Volterra kernel along various portions of the three dimensional frequency space were analyzed and compared with the symmetry of the Wiener and Hammerstein systems.

Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , x, 59 p.
Series
Trita-EE, ISSN 1653-5146 ; 2007:010
National Category
Telecommunications
Identifiers
URN: urn:nbn:se:kth:diva-24198ISBN: 978-91-7178-589-3 (print)OAI: oai:DiVA.org:kth-24198DiVA: diva2:345175
Public defence
2007-05-25, Sal 99:131, Högskolan i Gävle, Kungsbäcksvägen 47, Gävle, 13:00
Opponent
Supervisors
Note
QC 20100824Available from: 2010-08-24 Created: 2010-08-24 Last updated: 2011-09-08Bibliographically approved
List of papers
1. Wide-band dynamic modeling of power amplifiers using radial-basis function neural networks
Open this publication in new window or tab >>Wide-band dynamic modeling of power amplifiers using radial-basis function neural networks
2005 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 53, no 11, 3422-3428 p.Article in journal (Refereed) Published
Abstract [en]

A radial-basis function neural network (RBFNN) has been used for modeling the dynamic nonlinear behavior of an RF power amplifier for third generation. In the model, the signal's envelope is used. The model requires less training than a model using IQ data. Sampled input and output signals were used for identification and validation. Noise-like signals with bandwidths of 4 and 20 MHz were used. The RBFNN is compared to a parallel Hammerstein (PH) model. The two model types have similar performance when no memory is used. For the 4-MHz signal, the RBFNN has better in-band performance, whereas the PH is better out-of-band, when memory is used. For the 20-MHz; signal, the models have similar performance in- and out-of-band. Used as a digital-predistortion algorithm, the best RBFNN with memory suppressed the lower (upper) adjacent channel power 7 dB (4 dB) compared to a memoryless nonlinear predistorter and 11. dB (13 dB) compared to the case of no predistortion for the same output power for a 4-MHz-wide signal.

Keyword
Modeling; Neural networks (NNs); Nonlinear distortion; Power amplifiers (PAs); Radio transmitter
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7096 (URN)10.1109/TMTT.2005.855742 (DOI)000233122300021 ()
Note
QC 20100716Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2010-08-24Bibliographically approved
2. A Parameter-Reduced Volterra Model for Dynamic RF Power Amplifier Modeling based on Orthonormal Basis Functions
Open this publication in new window or tab >>A Parameter-Reduced Volterra Model for Dynamic RF Power Amplifier Modeling based on Orthonormal Basis Functions
2007 (English)In: International Journal of RF and Microwave Computer-Aided Engineering, ISSN 1096-4290, E-ISSN 1099-047X, Vol. 17, no 6, 542-551 p.Article in journal (Refereed) Published
Abstract [en]

A nonlinear dynamic behavioral model for radio frequency power amplifiers is presented. It uses orthonormal basis functions, Kautz functions, with complex poles that are different for each nonlinear order. It has the same general properties as Volterra models, but the number of parameters is significantly smaller. Using frequency weighting the out-of-band model error can be reduced. Using experimental data it was found that the optimal poles were the same for different input powers and for the different nonlinear orders. The optimal poles were also the same for direct and inverse models, which could be explained theoretically to be a general property of nonlinear systems with negligible linear memory effects. The model can be used as either a direct or inverse model with the same model error for power amplifiers with negligible linear memory effects.

Keyword
Inverse problems; Nonlinear distortion; Orthogonal functions; Parameter reduction; Power amplifiers; Radio transmitters
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7099 (URN)10.1002/mmce.20253 (DOI)000250212400004 ()
Note
QC 20100716. Uppdaterad från In press till Published 20100716.Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2010-08-24Bibliographically approved
3. A Comparative Analysis of Behavioral Models for RF Power Amplifiers
Open this publication in new window or tab >>A Comparative Analysis of Behavioral Models for RF Power Amplifiers
2006 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 54, no 1, 348-359 p.Article in journal (Refereed) Published
Abstract [en]

A comparative study of nonlinear behavioral models with memory for radio-frequency power amplifier (PAs) is presented. The models are static polynomial, parallel Hammerstein (PH), Volterra, and radial basis-function neural network (RBFNN). Two PAs were investigated: one was designed for the third-generation (3G) mobile telecommunication systems and one was designed for the second-generation (2G). The RBFNN reduced the total model error slightly more than the PH, but the error out of band was significantly lower for the PH. The Volterra was found to give a lower model error than did a PH of the same nonlinear order and memory depth. The PH could give a lower model error than the best Volterra, since the former could be identified with a higher nonlinear order and memory depth. The qualitative conclusions are the same for the 2G and 3G PAs, but the model errors are smaller for the latter. For the 3G PA, a static polynomial gave a low model error as low as the best PH and lower than the RBFNN for the hardest cross validation. The models with memory, PH, and RBFNN, showed better cross-validation performance, in terms of lower model errors, than a static polynomial for the hardest cross validation of the 2G PA.

Keyword
Modeling; Neural networks; Nonlinear distortion; Power amplifiers (PAs); Radio communication
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7753 (URN)10.1109/TMTT.2005.860500 (DOI)000234657600044 ()
Note
QC 20100716Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved
4. Digital predistortion of radio frequency power amplifiers using a Kautz-Volterra model
Open this publication in new window or tab >>Digital predistortion of radio frequency power amplifiers using a Kautz-Volterra model
2006 (English)In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 13, 780-782 p.Article in journal (Refereed) Published
Abstract [en]

A digital predistortion algorithm for radio frequency power amplifiers based on orthonormal basis functions is presented. It has the same general properties as a Volterra model, but fewer parameters. Experimentally, using a 3.84 MHz wide signal at 2.14 GHz, the adjacent channel power was suppressed 12 to 15 dB, which was 5 to 7 dB more than a polynomial predistorter.

Keyword
Algorithms; Mathematical models; Optical properties; Polynomials; Digital predistortion algorithm; Orthonormal basis functions; Polynomial predistorter; Power amplifiers
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7100 (URN)10.1049/el:20060460 (DOI)000239467200036 ()
Note
QC 20100716Available from: 2007-05-14 Created: 2007-05-14 Last updated: 2010-08-24Bibliographically approved
5. Three-Tone Characterization of Nonlinear Memory Effects in Radio Frequency Power Amplifier
Open this publication in new window or tab >>Three-Tone Characterization of Nonlinear Memory Effects in Radio Frequency Power Amplifier
2007 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, Vol. 56, no 6, 2646-2657 p.Article in journal (Refereed) Published
Abstract [en]

A stepped three-tone measurement technique based on digitally modulated baseband signals is used in characterizing radio-frequency power amplifiers (PAs). The bandwidths of the stepped measurement were 8.8 MHz for the input signal and 26.4 MHz for the output signal. A PA designed for third-generation mobile telecommunication system was analyzed. The amplitude and phase of the third-order Volterra kernel were determined from the identified intermodulation products. The properties of the Volterra kernel along certain paths in the 3-D frequency space were analyzed and compared to some box models for non-linear systems. The main symmetry of the third-order Volterra kernel of this PA was found to be of the type given by the cascaded quadratic nonlinearities with a linear filter in between (a Hammerstein-Wiener system), and frequency dependence, i.e., memory effects, was found to be due to the effects at the baseband.

Keyword
Behavioral model; Nonlinear; Power amplifier (PA); Radio frequency (RF); Symmetry properties; Volterra kernel
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-7756 (URN)10.1109/TIM.2007.907958 (DOI)000251745500065 ()
Note
QC 20100716. Uppdaterad från Accepted till Published 20100716.Available from: 2007-12-07 Created: 2007-12-07 Last updated: 2010-08-24Bibliographically approved

Open Access in DiVA

fulltext(1563 kB)4567 downloads
File information
File name FULLTEXT01.pdfFile size 1563 kBChecksum SHA-512
4135bdfa73796c0791a632f17a075598ff6a7a346824f217f96bfd7c4d68cb5b52f28194d224b2a7651e7a20ce9f91aff30320835f77711aa4aa635f4691694c
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Isaksson, Magnus
By organisation
Signal Processing
Telecommunications

Search outside of DiVA

GoogleGoogle Scholar
Total: 4567 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 857 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf