Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 332) Show all publications
Händel, P. & Wahlström, J. (2019). Digital contraceptives based on basal body temperature measurements. Biomedical Signal Processing and Control, 52, 141-151
Open this publication in new window or tab >>Digital contraceptives based on basal body temperature measurements
2019 (English)In: Biomedical Signal Processing and Control, ISSN 1746-8094, E-ISSN 1746-8108, Vol. 52, p. 141-151Article in journal (Refereed) Published
Abstract [en]

Digital contraceptives and fertility awareness products are currently offered as convenient smartphone applications. The first legitimate contraceptive smartphone app was recently introduced on the European market, with the digital processing based on measurements of the female user's basal body temperature (BBT). According to recent pilot market data, at some Swedish hospitals, up to 5–10% of women seeking abortion had become involuntarily pregnant while using the product. This fact motivates a review of the research on fertility determination based on BBT measurements. This paper provides the first estimation theoretical review and evaluation of BBT-based ovulation detection. From an engineering perspective, it is concluded that the available detection algorithms have similar performance and that the performance is rather insensitive to a one- or two-decimal resolution of the employed thermometer. Further, we highlight that when using the output from proposed ovulation detection algorithms, one must consider not only the uncertainty in the relative time difference of the detected temperature shift and the ovulation, but also the statistical uncertainty of the detection methods due to noisy measurements.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Basal body temperature method, Digital contraceptives, Fertility detection, Medical information systems, Ovulation detection, Commerce, mHealth, Physiology, Signal detection, Smartphones, Temperature measurement, Basal body temperatures (BBT), Body temperature, Body temperature measurements, Detection algorithm, Engineering perspective, Smart-phone applications, Statistical uncertainty, Uncertainty analysis
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:kth:diva-252467 (URN)10.1016/j.bspc.2019.04.019 (DOI)000473381100015 ()2-s2.0-85064463556 (Scopus ID)
Note

QC 20190715

Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-07-29Bibliographically approved
Händel, P. & Rönnow, D. (2019). Modeling Mixer and Power Amplifier Impairments. IEEE Microwave and Wireless Components Letters, 29(7), 441-443
Open this publication in new window or tab >>Modeling Mixer and Power Amplifier Impairments
2019 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 29, no 7, p. 441-443Article in journal (Refereed) Published
Abstract [en]

Combating the effects of mixer and power amplifier (PA) imperfections on transmitter performance is crucial for the design of wireless systems. PA compression and in-phase/quadrature imbalance are analyzed for a single-input-single-output transmitter model. The influence of the imperfection on the normalized mean squared error (NMSE) of the transmitter is studied using an analytical framework that relies on the classic Bussgang theory. The study concludes with a closed-form expression for the NMSE that provides insights into the behavior of the transmitter.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
Dirty radio, input backoff, orthogonal frequency division multiplexing (OFDM), power amplifier (PA)
National Category
Control Engineering
Identifiers
urn:nbn:se:kth:diva-255393 (URN)10.1109/LMWC.2019.2915647 (DOI)000474589400001 ()2-s2.0-85068688857 (Scopus ID)
Note

QC 20190729

Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-07-29Bibliographically approved
Ronnow, D. & Händel, P. (2019). Nonlinear Distortion Noise and Linear Attenuation in MIMO Systems-Theory and Application to Multiband Transmitters. IEEE Transactions on Signal Processing, 67(20), 5203-5212
Open this publication in new window or tab >>Nonlinear Distortion Noise and Linear Attenuation in MIMO Systems-Theory and Application to Multiband Transmitters
2019 (English)In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 67, no 20, p. 5203-5212Article in journal (Refereed) Published
Abstract [en]

Nonlinear static multiple-input multiple-output (MIMO) systems are analyzed. The matrix formulation of Bussgang's theorem for complex Gaussian signals is rederived and put in the context of the multivariate cumulant series expansion. The attenuation matrix is a function of the input signals' covariance and the covariance of the input and output signals. The covariance of the distortion noise is in addition a function of the output signal's covariance. The effect of the observation bandwidth is discussed. Models of concurrent multiband transmitters are analyzed. For a transmitter with dual non-contiguous hands expressions for the normalized mean square error (NMSE) vs input signal power are derived for uncorrelated, partially correlated, and correlated input signals. A transmitter with arbitrary number of non-contiguous hands is analysed for correlated and uncorrelated signals. In an example, the NMSE is higher when the input signals are correlated than when they are uncorrelated for the same input signal power and it increases with the number of frequency hands. A concurrent dual band amplifier with contiguous bands is analyzed; in this case the NMSE depends on the bandwidth of the aggregated signal.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Bussgang theory, carrier aggregation, concurrent dual band, MIMO, multiband transmitter, nonlinear distortion
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-261290 (URN)10.1109/TSP.2019.2935896 (DOI)000485741500001 ()
Note

QC 20191009

Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-10-09Bibliographically approved
Venkitaraman, A., Chatterjee, S. & Händel, P. (2019). On Hilbert transform, analytic signal, and modulation analysis for signals over graphs. Signal Processing, 156, 106-115
Open this publication in new window or tab >>On Hilbert transform, analytic signal, and modulation analysis for signals over graphs
2019 (English)In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 156, p. 106-115Article in journal (Refereed) Published
Abstract [en]

We propose Hilbert transform and analytic signal construction for signals over graphs. This is motivated by the popularity of Hilbert transform, analytic signal, and modulation analysis in conventional signal processing, and the observation that complementary insight is often obtained by viewing conventional signals in the graph setting. Our definitions of Hilbert transform and analytic signal use a conjugate symmetry-like property exhibited by the graph Fourier transform (GFT), resulting in a 'one-sided' spectrum for the graph analytic signal. The resulting graph Hilbert transform is shown to possess many interesting mathematical properties and also exhibit the ability to highlight anomalies/discontinuities in the graph signal and the nodes across which signal discontinuities occur. Using the graph analytic signal, we further define amplitude, phase, and frequency modulations for a graph signal. We illustrate the proposed concepts by showing applications to synthesized and real-world signals. For example, we show that the graph Hilbert transform can indicate presence of anomalies and that graph analytic signal, and associated amplitude and frequency modulations reveal complementary information in speech signals.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Graph signal processing, Analytic signal, Hilbert transform, Demodulation, Anomaly detection
National Category
Control Engineering
Identifiers
urn:nbn:se:kth:diva-240988 (URN)10.1016/j.sigpro.2018.10.016 (DOI)000453494200011 ()2-s2.0-85056192636 (Scopus ID)
Note

QC 20190110

Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-06-11Bibliographically approved
Wahlström, J., Jaldén, J., Skog, I. & Händel, P. (2018). Alternative em Algorithms for Nonlinear State-Space Models. In: 2018 21st International Conference on Information Fusion, FUSION 2018: . Paper presented at 21st International Conference on Information Fusion, FUSION 2018, 10 July 2018 through 13 July 2018 (pp. 1260-1267). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Alternative em Algorithms for Nonlinear State-Space Models
2018 (English)In: 2018 21st International Conference on Information Fusion, FUSION 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 1260-1267Conference paper, Published paper (Refereed)
Abstract [en]

The expectation-maximization algorithm is a commonly employed tool for system identification. However, for a large set of state-space models, the maximization step cannot be solved analytically. In these situations, a natural remedy is to make use of the expectation-maximization gradient algorithm, i.e., to replace the maximization step by a single iteration of Newton's method. We propose alternative expectation-maximization algorithms that replace the maximization step with a single iteration of some other well-known optimization method. These algorithms parallel the expectation-maximization gradient algorithm while relaxing the assumption of a concave objective function. The benefit of the proposed expectation-maximization algorithms is demonstrated with examples based on standard observation models in tracking and localization. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2018
Keywords
Expectation-maximization, Levenberg-Marquardt, system identification, the Gauss-Newton method, trust region, Identification (control systems), Image segmentation, Information fusion, Newton-Raphson method, Positron emission tomography, Religious buildings, Signal receivers, State space methods, Concave objective functions, Expectation - maximizations, Expectation-maximization algorithms, Gauss-Newton methods, Nonlinear state space models, State - space models, Maximum principle
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:kth:diva-236699 (URN)10.23919/ICIF.2018.8455234 (DOI)2-s2.0-85054096276 (Scopus ID)9780996452762 (ISBN)
Conference
21st International Conference on Information Fusion, FUSION 2018, 10 July 2018 through 13 July 2018
Funder
Swedish Foundation for Strategic Research
Note

Conference code: 139346; Export Date: 22 October 2018; Conference Paper; Funding details: SSF, Stiftelsen för Strategisk Forskning; Funding details: SSF, Sjögren’s Syndrome Foundation; Funding text: This research is financially supported by the Swedish Foundation for Strategic Research (SSF) via the project ASSEMBLE. QC 20181112

Available from: 2018-11-12 Created: 2018-11-12 Last updated: 2018-11-12Bibliographically approved
Alizadeh, M., Händel, P. & Rönnow, D. (2018). Basis Function Decomposition Approach in Piece-Wise Modeling for RF Power Amplifiers. In: 6th Telecommunications forum TELFOR 2018: . Paper presented at 26th Telecommunications forum TELFOR 2018, Serbia, Belgrade, November 20-21, 2018.. Belgrade, Serbia
Open this publication in new window or tab >>Basis Function Decomposition Approach in Piece-Wise Modeling for RF Power Amplifiers
2018 (English)In: 6th Telecommunications forum TELFOR 2018, Belgrade, Serbia, 2018Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, a new approach is proposed to decompose the basis functions in a piece-wise modeling technique for nonlinear radio frequency (RF) power amplifiers. The proposed technique treats the discontinuity problem of the model output at the joint points between different operating points, whereas preserves the linear and nonlinear properties of the original model within each region. Experimental results show that the proposed technique outperforms the conventional piece-wise model in terms of model errors.

Place, publisher, year, edition, pages
Belgrade, Serbia: , 2018
Keywords
Nonlinear dynamic RF power amplifier, behavioral modeling, piece-wise models, digital predistortion.
National Category
Signal Processing
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-241117 (URN)10.1109/TELFOR.2018.8611865 (DOI)000459714200035 ()2-s2.0-85062060510 (Scopus ID)978-1-5386-7171-9 (ISBN)
Conference
26th Telecommunications forum TELFOR 2018, Serbia, Belgrade, November 20-21, 2018.
Note

QC 20190114

Available from: 2019-01-11 Created: 2019-01-11 Last updated: 2019-05-21Bibliographically approved
Alizadeh, M., Händel, P. & Rönnow, D. (2018). Behavioural modelling and digital pre-distortion techniques for RF PAs in a 3x3 MIMO system. International journal of microwave and wireless technologies
Open this publication in new window or tab >>Behavioural modelling and digital pre-distortion techniques for RF PAs in a 3x3 MIMO system
2018 (English)In: International journal of microwave and wireless technologies, ISSN 1759-0795, E-ISSN 1759-0787Article in journal (Refereed) Submitted
Abstract [en]

Modern telecommunications are moving towards (massive) multi-input multi-output systems in 5th generation (5G) technology, increasing the dimensionality of the system dramatically. In this paper, the impairments of radio frequency (RF)power amplifiers (PAs) in a 3x3 MIMO system are compensated in both time and frequency domains. A three-dimensional(3D) time-domain memory polynomial-type model is proposed as an extension of conventional 2D models. Furthermore, a 3D frequency-domain technique is formulated based on the proposed time-domain model to reduce the dimensionality of the model, while preserving the performance in terms of model errors. In the 3D frequency-domain technique, the bandwidth of a system is split into several narrow sub-bands, and the parameters of the system are estimated for each subband. This approach requires less computational complexity, and also the procedure of the parameters estimation for each sub-band can be implemented independently. The device-under-test (DUT) consists of three RF PAs including input and output cross-talk channels. The proposed techniques are evaluated in both behavioural modelling and digital pre-distortion(DPD) perspectives. The results show that the proposed DPD technique can compensate the errors of non-linearity and memory effects by about 23.5 dB and 7 dB in terms of the normalized mean square error and adjacent channel leakage ratio, respectively.

Keywords
Radio frequency power amplifier, non-linearity, memory effects, multiple-input multiple-output (MIMO), digital pre-distortion.
National Category
Signal Processing
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-241118 (URN)
Note

QC 20190114

Available from: 2019-01-11 Created: 2019-01-11 Last updated: 2019-01-14Bibliographically approved
Händel, P. & Ronnow, D. (2018). Dirty MIMO Transmitters: Does It Matter?. IEEE Transactions on Wireless Communications, 17(8), 5425-5436
Open this publication in new window or tab >>Dirty MIMO Transmitters: Does It Matter?
2018 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 8, p. 5425-5436Article in journal (Refereed) Published
Abstract [en]

The radio frequency transmitter is a key component in contemporary multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing systems. A detailed study of a 2 x 2 MIMO transmitter subjected to correlated input data streams, nonlinear distortion, thermal noise, and crosstalk is provided by stochastic modeling. The effects of correlated input streams, crosstalk, and nonlinearities are studied in detail and exemplified both by approximate expressions and numerical simulations. Key results include exact and approximate expressions for the normalized mean-squared error (NMSE) for systems with or without digital predistortion; the relationship between NMSE and the signal-to-noise-and-distortion ratio, the properties of the distortion noise, and a novel design for power amplifier back-off for MIMO transmitters subject to crosstalk. The theoretical derivations are illustrated by numerical examples and simulation results, and their relationships to the state-of-the-art research are discussed.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Orthogonal frequency division multiplexing (OFDM), input back-off, power amplifier, optimization, Bussgang theory
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-234629 (URN)10.1109/TWC.2018.2843764 (DOI)000441933900034 ()2-s2.0-85048562714 (Scopus ID)
Note

QC 20190913

Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-13Bibliographically approved
Khan, Z. A., Zenteno, E., Händel, P. & Isaksson, M. (2018). Extraction of the Third-Order 3x3 MIMO VolterraKernel Outputs Using Multitone Signals. IEEE transactions on microwave theory and techniques, 66(11), 4985-4999
Open this publication in new window or tab >>Extraction of the Third-Order 3x3 MIMO VolterraKernel Outputs Using Multitone Signals
2018 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 66, no 11, p. 4985-4999Article in journal (Refereed) Published
Abstract [en]

This paper uses multitone signals to simplify theanalysis of 3×3 multiple-input multiple-output (MIMO) Volterrasystems by isolating the third-order kernel outputs from eachother. Multitone signals fed to an MIMO Volterra system yielda spectrum that is a permutation of the sums of the inputsignal tones. This a priori knowledge is used to design multitonesignals such that the third-order kernel outputs are isolated inthe frequency domain. The signals are designed by deriving theconditions for the offset and spacing of the input frequency grids.The proposed technique is then validated for the six possibleconfigurations of a 3x3 RF MIMO transmitter impaired bycrosstalk effects. The proposed multitone signal design is usedto extract the third-order kernel outputs, and their relativecontributions are analyzed to determine the dominant crosstalkeffects for each configuration.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-233974 (URN)10.1109/TMTT.2018.2854186 (DOI)000449354500028 ()
Note

QC 20180904

Available from: 2018-09-01 Created: 2018-09-01 Last updated: 2018-11-26Bibliographically approved
Venkitaraman, A., Chatterjee, S. & Händel, P. (2018). Extreme learning machine for graph signal processing. In: 2018 26th European Signal Processing Conference (EUSIPCO): . Paper presented at 26th European Signal Processing Conference, EUSIPCO 2018, Rome, Italy, 3 September 2018 through 7 September 2018 (pp. 136-140). European Signal Processing Conference, EUSIPCO, Article ID 8553088.
Open this publication in new window or tab >>Extreme learning machine for graph signal processing
2018 (English)In: 2018 26th European Signal Processing Conference (EUSIPCO), European Signal Processing Conference, EUSIPCO , 2018, p. 136-140, article id 8553088Conference paper, Published paper (Refereed)
Abstract [en]

In this article, we improve extreme learning machines for regression tasks using a graph signal processing based regularization. We assume that the target signal for prediction or regression is a graph signal. With this assumption, we use the regularization to enforce that the output of an extreme learning machine is smooth over a given graph. Simulation results with real data confirm that such regularization helps significantly when the available training data is limited in size and corrupted by noise.

Place, publisher, year, edition, pages
European Signal Processing Conference, EUSIPCO, 2018
Series
European Signal Processing Conference, ISSN 2219-5491
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-241525 (URN)10.23919/EUSIPCO.2018.8553088 (DOI)000455614900028 ()2-s2.0-85059801757 (Scopus ID)9789082797015 (ISBN)
Conference
26th European Signal Processing Conference, EUSIPCO 2018, Rome, Italy, 3 September 2018 through 7 September 2018
Note

QC 20180123

Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-02-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2718-0262

Search in DiVA

Show all publications