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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 2D extended envelope memory polynomial (2D-EEMP) 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 pre-distortion (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-art2D-DPD and dual-band generalized memory polynomial (DB-GMP) models. Experimental result shows that the proposed model resulted in normalized mean square error (NMSE) of -51.7/-51.6dB and adjacent channel error power ratio (ACEPR) 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 3 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 (ACPR) of -55.8/ -54.6 dB for channel 1/2 and is 7-10 dB lower than those resulted with the 2D-DPD model and2-4 dB lower compared to the DB-GMP model.

Keywords
Behavioral modeling and digital predistortion of multi-band amplifiers, Power Amplifiers, RF Front-ends
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-23455 (URN)10.1017/S1759078717000277 (DOI)000418998100010 ()2-s2.0-85018373558 (Scopus ID)
Available from: 2016-12-05 Created: 2017-02-02 Last updated: 2018-03-13Bibliographically 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.

Abstract [sv]

Världen av idag har omvandlats starkt av framsteg inom trådlos teknik. Framtidens smarta samhalle där samspelet mellan fysiska och virtuella dimensioner i livet är sammanflätade och där mansklig växelverkan mer ofta än inte sker med eller formedlas av maskiner - exempelvis smarta telefoner - kräver allt mer datatrafik. Denna ständigt ökande datatrafik kraver i sin tur utformning av trådlös teknik som kan rymma flera kanaler och flera frekvensband för att öka systements kapactitet och flexibilitet. I denna avhandling diskuteras aspekter relaterade till beteendemodellering, karakterisering, och kompensering av ickelinjär distortion i radiofrekvens (RF) effektforstarkare (PA) för multipla-insignaler-multipla-utsignaler (MIMO) och samtidiga signaler i dubbla frekvensband.

När man gör en modell av ett system är det fordelaktigt att ta hänsyn till kunskap om det fysikaliska systemet och använda denna information i modellen. Denna strategi skulle kunna bidra till att forbattra modellens prestanda och minska antalet modellparametrar. I detta sammanhang föreslås tre nya beteende- och DPD-modeller för ickelinjära MIMO sändare. Olika typer av överhörning i MIMO-sändare undersöks för att härleda enkla och kraftfulla modeller. Effekter av koherent och partiellt koherent signalgenerering på DPD-prestanda utvärderas också. För att modellera och kompensera ickelinjär distortion i galliumnitridbaserade (GaN) RF PA med langtidsminneseffekter föreslås två nya modeller for RF PA med en in- och en utsignal (SISO) tre nya modeller för RF PA för samtidiga signaler i olika frekvensband. Dessa modeller är baserade på teknik med expansion runt fasta polvärden och har oändligt minnesdjup. Modellerna visar betydande resultatförbättring i jämforelse med dem med ändliga impulssvar. En beteendemodell baserad på en fysikalisk modell av förstärkaren föreslås för en PA för samtidiga signaler i olika frekvensband. Dess prestanda undersöks som beteendemodell och för utjämning av ickelinjär distortion.

Tvåtonskarakterisering är som ett fingeravtryck vid karakterisering av minneseffekter i dynamiska ickelinjära system. I detta sammanhang föreslås två nya tekniker för karakterisering av sändare för samtidiga signaler med olika frekvens och och MIMO-sändare. Den första tekniken är en dubbel tvåtonskarakterisering för de individuella minneseffekterna i egen- och korsmoduleringsprodukter i sändare med samtidiga signaler i olika frekvensband. Den andra tekniken är för karakterisering och analys av egen- och korsvolterrakärnor hos ett ickelinjärt 3×3 MIMO-system med hjalp av tre-tonssignaler. I den föreslagna tekniken analyseras egen- och korskänor längs linjer i en frekvensrymd för att fastställa blockstrukturer hos det underliggande systemet. Den kunskap som erhållits med hjälp av denna karakeriseringsteknik har kunnat användas för att modifiera tidigare publicerade beteendemodeller.

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
Identifiers
urn:nbn:se:hig:diva-23287 (URN)978-91-7729-198-5 (ISBN)
Public defence
2017-02-24, 99:133, Kungsbäcksvägen 47, Gävle, 10:15 (English)
Opponent
Supervisors
Available from: 2017-02-02 Created: 2017-01-11 Last updated: 2018-03-13Bibliographically approved
Amin, S., Händel, P. & Rönnow, D. (2017). Digital Predistortion of Single and Concurrent Dual Band Radio Frequency GaN Amplifiers with Strong Nonlinear Memory Effects. IEEE transactions on microwave theory and techniques, 65(7), 2453-2464, Article ID 7855827.
Open this publication in new window or tab >>Digital Predistortion of Single and Concurrent Dual Band Radio Frequency GaN Amplifiers with Strong Nonlinear Memory Effects
2017 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 65, no 7, p. 2453-2464, article id 7855827Article in journal (Refereed) Published
Abstract [en]

Electrical anomalies due to trapping effects in Gallium Nitride (GaN) power amplifiers (PAs)give rise to long-term or strong memory effects. We propose novel models based on infinite impulse response (IIR) fixed pole expansion techniques for the behavioural modeling and digital pre-distortion of single-input-single-output (SISO) and concurrent dual-bandGaN PAs. Experimental results show that the proposed models outperform the corresponding finite impulse response (FIR) models by up to 17 dB for the same number of model parameters. For the linearization of a SISO GaN PA the proposed models give adjacent channel power ratios (ACPRs) that are 7 to 17 dBlower than the FIR models. For the concurrent dual-band case, the proposed models give ACPRs that are 9to 14 dB lower than the FIR models.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
Behavioral modeling; concurrent dual band; digital predistortion (DPD); finite impulse response (FIR); infinite impulse response (IIR); power amplifiers (PAs); radio frequency; single-input single-output (SISO)
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-23117 (URN)10.1109/TMTT.2016.2642948 (DOI)000405006300023 ()2-s2.0-85012982096 (Scopus ID)
Available from: 2016-12-20 Created: 2016-12-20 Last updated: 2018-03-13Bibliographically approved
Alizadeh, M., Amin, S. & Rönnow, D. (2017). Measurement and analysis of frequency-domain Volterra kernels of nonlinear dynamic 3x3 MIMO systems. IEEE Transactions on Instrumentation and Measurement, 66(7), 1893-1905
Open this publication in new window or tab >>Measurement and analysis of frequency-domain Volterra kernels of nonlinear dynamic 3x3 MIMO systems
2017 (English)In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 66, no 7, p. 1893-1905Article in journal (Refereed) Published
Abstract [en]

Multiple-input multiple-output (MIMO) frequency-domain Volterra kernels of nonlinear order 3 are experimentally determined in bandwidth-limited frequency regions. How the effect of higher nonlinear orders can be reduced and how this affects the estimated errors are discussed. The magnitude and phase of the kernels areKramers-Kronig consistent. The self- and cross-kernels have different symmetries and the kernels are therefore determined and analyzed in different regions in the 3D frequency space. By analyzing the properties along certain paths in the 3D frequency space, the block structures for the respective kernels are determined. These block structures contain the significant blocks of the general block structures for third-order kernels. The device under test is a MIMO transmitter for radio frequency signals.

Place, publisher, year, edition, pages
IEEE Press, 2017
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-23216 (URN)10.1109/TIM.2017.2664482 (DOI)000403292600026 ()2-s2.0-85014208551 (Scopus ID)
Available from: 2016-12-05 Created: 2017-01-05 Last updated: 2019-02-18Bibliographically 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.

National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-23281 (URN)10.1049/iet-smt.2016.0203 (DOI)000396470900012 ()2-s2.0-85008869311 (Scopus ID)
Available from: 2017-01-11 Created: 2017-01-11 Last updated: 2018-03-13Bibliographically approved
Amin, S., Händel, P. & Rönnow, D. (2016). Characterization and modeling of RF amplifiers with multiple input signals. In: : . Paper presented at Swedish Microwave days (GigaHertz Symposium), 15-16 March 2016, Linköping, Sweden.
Open this publication in new window or tab >>Characterization and modeling of RF amplifiers with multiple input signals
2016 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

A characterization technique for RF PAs excited with multiple signals is presented. The technique can be used for characterization of memory effects in IM/CM products. The extracted information can in return be of use for modifying behavioral models to better capture memory in IM/CM products.

National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-22303 (URN)
External cooperation:
Conference
Swedish Microwave days (GigaHertz Symposium), 15-16 March 2016, Linköping, Sweden
Available from: 2016-08-25 Created: 2016-08-25 Last updated: 2018-03-13Bibliographically approved
Amin, S., Khan, Z. A., Isaksson, M., Händel, P. & Rönnow, D. (2016). Concurrent dual-band power amplifier model modification using dual two-tone test. In: 46th Europena Microwave Conference (EUMC) 2016: . Paper presented at 46th European Microwave Conference (EuMC), 4-6 October 2016, London, UK (pp. 186-189).
Open this publication in new window or tab >>Concurrent dual-band power amplifier model modification using dual two-tone test
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2016 (English)In: 46th Europena Microwave Conference (EUMC) 2016, 2016, p. 186-189Conference paper, Published paper (Refereed)
Abstract [en]

A dual two-tone technique for the characterization of memory effects in concurrent dual-band transmitters is revisited to modify a 2D-DPD model for the linearization of concurrent dual-band transmitters. By taking into account the individual nonlinear memory effects of the self- and cross-kernels, a new2D modified digital pre-distortion (2D-MDPD) model is proposed,which not only supersedes the linearization performance but also reduces the computational complexity compared to the 2DDPDmodel in terms of a number of floating point operations(FLOPs). Experimental results show an improvement of 1.7 dBin normalized mean square error (NMSE) and a 58% reduction in the number of FLOPs.

Series
European Microwave Conference, ISSN 2325-0305
Keywords
IEEE Keywords Computational modeling, Numerical models, Dual band, Two dimensional displays, Radio frequency, Computational complexity
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-22558 (URN)10.1109/EuMC.2016.7824309 (DOI)000393581100048 ()2-s2.0-85015185570 (Scopus ID)978-2-87487-043-9 (ISBN)978-1-5090-1514-6 (ISBN)
Conference
46th European Microwave Conference (EuMC), 4-6 October 2016, London, UK
Available from: 2016-10-06 Created: 2016-10-06 Last updated: 2018-12-03Bibliographically approved
Amin, S. (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 requirethe development of wireless systems that can support wide and multi-bandsignals. To deploy these signals, new radio frequency (RF) front-ends are requiredwhich impose new challenges in terms of power consumption efficiencyand sources of distortion e.g., nonlinearity. These challenges are more pronouncedin power amplifiers (PAs) that degrade the overall performance ofthe RF transmitter.Since it is difficult to optimize the linearity and efficiency characteristicsof a PA simultaneously, a trade-off is needed. At high input power, a PAexhibits high efficiency at the expense of linearity. On the other hand, atlow input power, a PA is linear at the expense of the efficiency. To achievelinearity and efficiency at the same time, digital pre-distortion (DPD) is oftenused to compensate for the PA nonlinearity at high input power. In case ofmulti-channel PAs, input and output signals of different channels interactwith each other due to cross-talk. Therefore, these PAs exhibit differentnonlinear behavior than the single-input single-output (SISO) PAs. The DPDtechniques developed for SISO PAs do not result in adequate performancewhen used for multi-channel PAs. Hence, an accurate behavioral modeling isessential for the development of DPD for multi-channel RF PAs.In this thesis, we propose three novel behavioral models and DPD schemesfor nonlinear multiple-input multiple-output (MIMO) transmitters in presenceof cross-talk. A study of the source of cross-talk in MIMO transmittershave 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 thatwith partially non-coherent signal generation, the performance of the DPDdegrades compared to coherent signal generation.In context of multi-channel RF transmitters, PA behavioral models andDPD schemes suffer from a large number of model parameters with the increasein nonlinear order and memory depth. This growth leads to highcomplexity model identification and implementation. We have designed aDPD scheme for MIMO PAs using a sparse estimation technique for reducingmodel complexity. This technique also increases the numerical stability whenlinear least square estimation model identification is used.A method to characterize the memory effects in a nonlinear concurrentdual-band PAs is also presented. Compared to the SISO PAs, concurrentdual-band PAs are not only affected by intermodulation distortions but alsoby cross-modulation distortions. The characterization of memory effects inconcurrent dual-band transmitter is performed by injecting a two-tone testsignal in each input channel of the transmitter. Asymmetric energy surfacesare introduced for the intermodulation and cross-modulation products, whichcan 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. 45
Series
TRITA-EE, ISSN 1653-5146 ; 2015:001
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-18848 (URN)
Presentation
2015-01-23, 99132, Kungsbäcksvägen 47, Gävle, 10:00 (English)
Opponent
Supervisors
Available from: 2015-01-27 Created: 2015-01-26 Last updated: 2018-03-13Bibliographically 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, 64(10), 2781-2791, Article ID 7104121.
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, Vol. 64, no 10, p. 2781-2791, article id 7104121Article 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
Concurrent dual-band, power amplifier, characterization, linearization, nonlinear distortion, MIMO, DPD
National Category
Signal Processing
Identifiers
urn:nbn:se:hig:diva-18854 (URN)10.1109/TIM.2015.2427731 (DOI)000361487500019 ()2-s2.0-84959505984 (Scopus ID)
Available from: 2014-12-17 Created: 2015-01-27 Last updated: 2018-03-13Bibliographically approved
Flattery, K., Amin, S., Mahamat, Y., Eroglu, A. & Rönnow, D. (2015). High Power Combiner/Divider Design for Dual Band RF Power Amplifiers. In: Proceedings of the 2015 International Conference on Electromagnetics in Advanced Applications: ICEAA 2015. Paper presented at 17th International Conference on Electromagnetics in Advanced Applications, ICEAA 2015, 7-11 September 2015, Torino, Italy (pp. 1036-1039). IEEE Press
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: Proceedings of the 2015 International Conference on Electromagnetics in Advanced Applications: ICEAA 2015, IEEE Press, 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 Press, 2015
Keywords
amplifier, combiner, divider, dual band, Radio Frequency
National Category
Telecommunications
Identifiers
urn:nbn:se:hig:diva-20246 (URN)10.1109/ICEAA.2015.7297272 (DOI)000378428800197 ()2-s2.0-84955502943 (Scopus ID)978-147997806-9 (ISBN)
Conference
17th International Conference on Electromagnetics in Advanced Applications, ICEAA 2015, 7-11 September 2015, Torino, Italy
Note

Article number: 7297272

Available from: 2015-09-10 Created: 2015-09-10 Last updated: 2018-03-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1183-6666

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