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Publications (10 of 11) Show all publications
Amin, S., Landin, P. N., Händel, P. & Rönnow, D. (2017). 2D Extended envelope memory polynomial model for concurrent dual-band RF transmitters. International journal of microwave and wireless technologies, 9(8), 1619-1627
Open this publication in new window or tab >>2D Extended envelope memory polynomial model for concurrent dual-band RF transmitters
2017 (English)In: International journal of microwave and wireless technologies, ISSN 1759-0795, E-ISSN 1759-0787, Vol. 9, no 8, p. 1619-1627Article in journal (Refereed) Published
Abstract [en]

The paper presents a two-dimensional (2D) extended envelope memory polynomial model for concurrent dual-band radio frequency (RF) power amplifiers (PAs). The model is derived based on the physical knowledge of a dual-band RF PA. The derived model contains cross-modulation terms not included in previously published models; these terms are found to be of importance for both behavioral modeling and digital predistortion (DPD). The performance of the derived model is evaluated both as the behavioral model and DPD, and the performance is compared with state-of-the-art 2D-DPD and dual-band generalized memory polynomial (DB-GMP) models. Experimental result shows that the proposed model resulted in normalized mean square error of -51.7/-51.6 dB and adjacent channel error power ratio of -63.1/-63.4 dB, for channel 1/2, whereas the 2D-DPD resulted in the largest model error and DB-GMP resulted in model parameters that are three times more than those resulted with the proposed model with the same performance. As pre-distorter, the proposed model resulted in adjacent channel power ratio of -55.8/-54.6 dB for channel 1/2 and is 7-10 dB lower than those resulted with the 2D-DPD model and 2-4 dB lower compared with the DB-GMP model.

Place, publisher, year, edition, pages
Cambridge University Press, 2017
Keywords
Power Amplifiers, RF Front-ends, Behavioral modeling and digital predistortion of multi-band amplifiers
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-221397 (URN)10.1017/S1759078717000277 (DOI)000418998100010 ()2-s2.0-85018373558 (Scopus ID)
Note

QC 20180117

Available from: 2018-01-17 Created: 2018-01-17 Last updated: 2018-01-17Bibliographically approved
Amin, S. (2017). Characterization and Linearization of Multi-band Multi-channel RF Power Amplifiers. (Doctoral dissertation). Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Characterization and Linearization of Multi-band Multi-channel RF Power Amplifiers
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The World today is deeply transformed by the advancement in wireless technology. The envision of a smart society where interactions between physical and virtual dimensions of life are intertwined and where human interaction is mediated by machines, e.g., smart phones, demands increasingly more data traffic. This continual increase in data traffic requires re-designing of the wireless technologies for increased system capacity and flexibility. In this thesis, aspects related to behavioral modeling, characterization, and linearization of multi-channel/band power amplifiers (PAs) are discussed.

When building a model of any system, it is advantageous to take into account the knowledge of the physics of the system and include into the model. This approach could help to improve the model performance. In this context, three novel behavioral models and DPD schemes for nonlinear MIMO transmitters are proposed.

To model and compensate distortions in GaN based RF PAs in presence of long-term memory effects, novel models for SISO and concurrent dual-band PAs are proposed. These models are based on a fixed pole expansion technique and have infinite impulse response. They show substantial performance improvement. A behavioral model based on the physical knowledge of the concurrent dual-band PA is derived, and its performance is investigated both for behavioral modeling and compensation of nonlinear distortions.

Two-tone characterization is a fingerprint method for the characterization of memory effects in dynamic nonlinear systems. In this context, two novel techniques are proposed. The first technique is a dual two-tone characterization technique to characterize the memory effects of self- and cross-modulation products in concurrent dual-band transmitter. The second technique is for the characterization and analysis of self- and cross-Volterra kernels of nonlinear 3x3 MIMO systems using three-tone signals.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. p. 59
Series
TRITA-EE, ISSN 1653-5146 ; 2016:185
National Category
Signal Processing
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-197266 (URN)978-91-7729-198-5 (ISBN)
Public defence
2017-02-24, 99133, Kungsbäcksvägen 47, Gävle, 10:15 (English)
Opponent
Supervisors
Note

QC 20161205

Available from: 2016-12-05 Created: 2016-11-30 Last updated: 2016-12-05Bibliographically approved
Rönnow, D., Amin, S., Alizadeh, M. & Zenteno, E. (2017). Phase noise coherence of two continuous wave radio frequency signals of different frequency. IET Science, Measurement & Technology, 11(1), 77-85
Open this publication in new window or tab >>Phase noise coherence of two continuous wave radio frequency signals of different frequency
2017 (English)In: IET Science, Measurement & Technology, ISSN 1751-8822, E-ISSN 1751-8830, Vol. 11, no 1, p. 77-85Article in journal (Refereed) Published
Abstract [en]

A method is proposed for determining the correlated and uncorrelated parts of phase noise spectra (PNS) of two continuous wave radio signals of different frequencies, ω1 and ω2. The PNS of the two signals and of mixed signals are measured. The PNS are modelled as having a correlated part that is the same for both signals, except for a multiplicative factor, and uncorrelated parts, that are different for the two signals. A property of the model that the PNS of some mixing products are linear combinations of the PNS of the signals at ω1, ω2, and ω1 - ω2 is experimentally verified. The difference of the PNS at ω1 + ω2 and ω1 - ω2 is proportional to the correlated part of the PNS and is a part of auxiliary functions that are used for finding the multiplicative factor and the correlated, partly correlated, and uncorrelated phase noise at different offset frequencies. A conventional spectrum analyser was used to characterise two signal generators, a phase-coherent and a non-phase-coherent one. For the phase-coherent generator the phase noise of two signals was found to be correlated for offset frequencies below 10 Hz, partly correlated for 10 Hz-1 kHz and uncorrelated above 1 kHz.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2017
Keywords
Spectrum analyzers, Auxiliary functions, Continuous Wave, Correlated parts, Linear combinations, Multiplicative factors, Offset frequencies, Phase coherent, Phase noise spectrum, Phase noise
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-202267 (URN)10.1049/iet-smt.2016.0203 (DOI)000396470900012 ()2-s2.0-85008869311 (Scopus ID)
Note

Correspondence Address: Rönnow, D.; Department of Electronics, Mathematics and Natural Sciences, University of GävleSweden; email: daniel.Ronnow@hig.se. QC 20170221

Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
Amin, S. A. (2015). Characterization and Linearization of Multi-channel RF Power Amplifiers. (Licentiate dissertation). Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Characterization and Linearization of Multi-channel RF Power Amplifiers
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The demands for high data rates and broadband wireless access require the development of wireless systems that can support wide and multi-band signals. To deploy these signals, new radio frequency (RF) front-ends are required which impose new challenges in terms of power consumption efficiency and sources of distortion e.g., nonlinearity. These challenges are more pronounced in power amplifiers (PAs) that degrade the overall performance of the RF transmitter. Since it is difficult to optimize the linearity and efficiency characteristics of a PA simultaneously, a trade-off is needed. At high input power, a PA exhibits high efficiency at the expense of linearity. On the other hand, at low input power, a PA is linear at the expense of the efficiency. To achieve linearity and efficiency at the same time, digital pre-distortion (DPD) is often used to compensate for the PA nonlinearity at high input power. In case of multi-channel PAs, input and output signals of different channels interact with each other due to cross-talk. Therefore, these PAs exhibit different nonlinear behavior than the single-input single-output (SISO) PAs. The DPD techniques developed for SISO PAs do not result in adequate performance when used for multi-channel PAs. Hence, an accurate behavioral modeling is essential for the development of DPD for multi-channel RF PAs. In this thesis, we propose three novel behavioral models and DPD schemes for nonlinear multiple-input multiple-output (MIMO) transmitters in presence of cross-talk. A study of the source of cross-talk in MIMO transmitters have been investigated to derive simple and powerful modeling schemes. These models are extensions of a SISO generalized memory polynomial model. A comparative study with a previously published MIMO model is also presented. The effect of coherent and partially non-coherent signal generationon DPD performance is also highlighted. It is shown experimentally that with partially non-coherent signal generation, the performance of the DPD degrades compared to coherent signal generation. In context of multi-channel RF transmitters, PA behavioral models and DPD schemes suffer from a large number of model parameters with the increase in nonlinear order and memory depth. This growth leads to high complexity model identification and implementation. We have designed a DPD scheme for MIMO PAs using a sparse estimation technique for reducing model complexity. This technique also increases the numerical stability when linear least square estimation model identification is used. A method to characterize the memory effects in a nonlinear concurrent dual-band PAs is also presented. Compared to the SISO PAs, concurrent dual-band PAs are not only affected by intermodulation distortions but also by cross-modulation distortions. The characterization of memory effects inconcurrent dual-band transmitter is performed by injecting a two-tone test signal in each input channel of the transmitter. Asymmetric energy surfaces are introduced for the intermodulation and cross-modulation products, which can be used to identify the power and frequency regions where the memory effects are dominant.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. p. vii, 45
Series
TRITA-EE, ISSN 1653-5146 ; 2015:001
National Category
Signal Processing
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-157154 (URN)978-91-7595-388-5 (ISBN)
Presentation
2015-01-23, 99132, Kungsbäcksvägen 47, Gävle, 10:00 (English)
Opponent
Supervisors
Note

QC 20141217

Available from: 2014-12-17 Created: 2014-12-08 Last updated: 2016-11-30Bibliographically approved
Amin, S., Van Moer, W., Händel, P. & Rönnow, D. (2015). Characterization of concurrent dual-band Power Amplifiers using a dual two-tone excitation signal. IEEE Transactions on Instrumentation and Measurement (99)
Open this publication in new window or tab >>Characterization of concurrent dual-band Power Amplifiers using a dual two-tone excitation signal
2015 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, no 99Article in journal (Refereed) Published
Abstract [en]

A method to characterize the memory effects in a nonlinear concurrent dual-band transmitter is presented. It is an extension of the conventional two tone test for power amplifiers to concurrent dual band transmitters. The output signal of a concurrent dual-band transmitter is affected not only by intermodulation products but also by cross-modulation products. In one frequency band, the transmitter is excited by a two tone signal which frequency separation is swept. In the second band the transmitter is concurrently excited by an other two tone signal with slightly wider frequency separation. The frequency difference of the two signals is fixed during the frequency sweep. The two tone test is made at different power levels. The upper and lower third-order inter- and cross-modulation products are measured. The asymmetry between the upper and lower third-order inter- and cross-modulation products are measures of the transmitter's memory effects. The measurement results show that the memory effects are more dominant in the third-order intermodulation products than in the cross modulation products. An error analysis and system calibration was performed and measurement results for two different devices are presented.

Place, publisher, year, edition, pages
IEEE Press, 2015
Keywords
Amplifier distortion, concurrent dual band, cross modulation (CM), digital predistortion (DPD), intermodulation (IM), multiple input multiple output (MIMO), power amplifier (PA)
National Category
Signal Processing
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-165415 (URN)10.1109/TIM.2015.2427731 (DOI)2-s2.0-84959505984 (Scopus ID)
Note

QC 20150604

Available from: 2015-04-28 Created: 2015-04-28 Last updated: 2019-09-20Bibliographically approved
Flattery, K., Amin, S., Rönnow, D., Mahamat, Y. & Eroglu, A. (2015). High Power Combiner/Divider Design for Dual Band RF Power Amplifiers. In: IEEE International Conference on Electromagnetics in Advanced Applications: . Paper presented at IEEE International Conference on Electromagnetics in Advanced Applications,7-11 Sept. 2015, Turin (pp. 1036-1039). IEEE conference proceedings
Open this publication in new window or tab >>High Power Combiner/Divider Design for Dual Band RF Power Amplifiers
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2015 (English)In: IEEE International Conference on Electromagnetics in Advanced Applications, IEEE conference proceedings, 2015, p. 1036-1039Conference paper, Published paper (Refereed)
Abstract [en]

Design of low loss with an enhanced thermal profile power divider/combiner for high power dual-band Radio Frequency (RF) power amplifier applications is given. The practical implementation, low loss and substrate characteristics make this type of combiner ideal for high power microwave applications.  The combiner operational frequencies are chosen to operate at 900 MHz and 2.14 GHz, which are common frequencies for concurrent dual band RF power amplifiers. The analytical results are verified with simulation results for various cases and agreement has been observed on all of them. 

Place, publisher, year, edition, pages
IEEE conference proceedings, 2015
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-173368 (URN)10.1109/ICEAA.2015.7297272 (DOI)000378428800197 ()2-s2.0-84955502943 (Scopus ID)
Conference
IEEE International Conference on Electromagnetics in Advanced Applications,7-11 Sept. 2015, Turin
Note

Qc 20151211

Available from: 2015-09-10 Created: 2015-09-10 Last updated: 2016-08-09Bibliographically approved
Amin, S., Landin, P., Händel, P. & Rönnow, D. (2014). Behavioral modeling and linearization of crosstalk and memory effects in RF MIMO transmitters. IEEE transactions on microwave theory and techniques, 62(4), 810-823
Open this publication in new window or tab >>Behavioral modeling and linearization of crosstalk and memory effects in RF MIMO transmitters
2014 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 62, no 4, p. 810-823Article in journal (Refereed) Published
Abstract [en]

This paper proposes three novel models for behavioral modeling and digital pre-distortion (DPD) of nonlinear 2 x 2 multiple-input multiple-output (MIMO) transmitters in the presence of crosstalk. The proposed models are extensions of the single-input single-output generalized memory polynomial model. Three types of crosstalk effects were studied and characterized as linear, nonlinear, and nonlinear & linear crosstalk. A comparative study was performed with previously published models for the linearization of crosstalk in a nonlinear 2 x 2 MIMO transmitter. The experiments indicate that, depending on the type of crosstalk, the selection of the correct model in the transmitter is necessary for behavioral modeling and sufficient DPD performance. The effects of coherent and partially noncoherent signal generation on the performance of DPD were also studied. For crosstalk levels of 30 dB, the difference in the normalized mean square error and adjacent channel power ratio was found to be 3-4 dB between coherent and partially noncoherent signal generation.

Keywords
Behavioral modeling, digital pre-distortion (DPD), multiple-input multiple-output (MIMO), nonlinear and linear crosstalk, power amplifiers (PAs), RF
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-142568 (URN)10.1109/TMTT.2014.2309932 (DOI)000334525600010 ()2-s2.0-84898403156 (Scopus ID)
Note

QC 20140505

Available from: 2014-03-13 Created: 2014-03-07 Last updated: 2017-12-05Bibliographically approved
Amin, S., Van Moer, W., Händel, P. & Rönnow, D. (2014). Characterization of a Concurrent dual-band Power Amplifier using a dual-tone excitation signals. IEEE Transactions on Instrumentation and Measurement
Open this publication in new window or tab >>Characterization of a Concurrent dual-band Power Amplifier using a dual-tone excitation signals
2014 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662Article in journal (Other academic) Submitted
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-157862 (URN)
Note

QC 20141217

Available from: 2014-12-17 Created: 2014-12-17 Last updated: 2017-12-05Bibliographically approved
Zenteno, E., Amin, S., Isaksson, M., Ronnow, D. & Händel, P. (2014). Combating the Dimensionality of Nonlinear MIMO Amplifier Predistortion by Basis Pursuit. In: 2014 44TH EUROPEAN MICROWAVE CONFERENCE (EUMC): . Paper presented at 44th European Microwave Conference (EuMC), OCT 05-10, 2014, Rome, ITALY (pp. 833-836). IEEE
Open this publication in new window or tab >>Combating the Dimensionality of Nonlinear MIMO Amplifier Predistortion by Basis Pursuit
Show others...
2014 (English)In: 2014 44TH EUROPEAN MICROWAVE CONFERENCE (EUMC), IEEE , 2014, p. 833-836Conference paper, Published paper (Refereed)
Abstract [en]

A general description of nonlinear dynamic MIMO systems, given by Volterra series, has significantly larger complexity than SISO systems. Modeling and predistortion of MIMO amplifiers consequently become unfeasible due to the large number of basis functions. We have designed digital predistorters for a MIMO amplifier using a basis pursuit method for reducing model complexity. This method reduces the numerical problems that appear in MIMO Volterra predistorters due to the large number of basis functions. The number of basis functions was reduced from 1402 to 220 in a 2x2 MIMO amplifier and from 127 to 13 in the corresponding SISO case. Reducing the number of basis functions caused an increase of approximately 1 dB of model error and adjacent channel power ratio.

Place, publisher, year, edition, pages
IEEE, 2014
Series
European Microwave Conference, ISSN 2325-0305
Keywords
Digital pre distortion (DPD), MIMO power amplifiers, LASSO, basis pursuit, power amplifier linearization
National Category
Control Engineering
Identifiers
urn:nbn:se:kth:diva-243771 (URN)000392912200209 ()978-2-87487-035-4 (ISBN)
Conference
44th European Microwave Conference (EuMC), OCT 05-10, 2014, Rome, ITALY
Note

QC 20190212

Available from: 2019-02-12 Created: 2019-02-12 Last updated: 2019-02-12Bibliographically approved
Zenteno, E., Amin, S., Isaksson, M. & Händel, P. (2014). Combating the Dimensionality of Nonlinear MIMOAmplifier Predistortion by Basis Pursuit. In: Proceedings of the 44th European Microwave Conference: . Paper presented at 44th European Microwave Conference,Roma, Italy on October 5-10, 2014 (pp. 833-836).
Open this publication in new window or tab >>Combating the Dimensionality of Nonlinear MIMOAmplifier Predistortion by Basis Pursuit
2014 (English)In: Proceedings of the 44th European Microwave Conference, 2014, p. 833-836Conference paper, Published paper (Refereed)
Abstract [en]

A general description of nonlinear dynamic MIMOsystems, given by Volterra series, has significantly larger complex-ity than SISO systems. Modeling and predistortion of MIMOamplifiers consequently become unfeasible due to the largenumber of basis functions. We have designed digital predistortersfor a MIMO amplifier using a basis pursuit method for reducingmodel complexity. This method reduces the numerical problemsthat appear in MIMO Volterra predistorters due to the largenumber of basis functions. The number of basis functions wasreduced from 1402 to 220 in a 2x2 MIMO amplifier and from127 to 13 in the corresponding SISO case. Reducing the numberof basis functions caused an increase of approximately 1 dB ofmodel error and adjacent channel power ratio.

Keywords
Digital pre distortion (DPD), MIMO power ampli- fiers, LASSO, basis pursuit, power amplifier linearization.
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Communication Systems
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-154563 (URN)
Conference
44th European Microwave Conference,Roma, Italy on October 5-10, 2014
Note

QC 20141117

Available from: 2014-10-23 Created: 2014-10-23 Last updated: 2016-11-30Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1183-6666

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