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  • 101.
    Händel, Peter
    Tampere University of Technology.
    Predictive FIR/IIR filters for narrow-band waveforms1997In: The First European Conference on Signal Analysis andPrediction, ECSAP-97, Prague, Czech Republic,24-27 June 1997, 1997, p. 171-174Conference paper (Refereed)
  • 102.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Properties of the IEEE-STD-1057 four-parameter sine wave fit algorithm2000In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 49, no 6, p. 1189-1193Article in journal (Refereed)
  • 103.
    Händel, Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Understanding Normalized Mean Squared Error in Power Amplifier Linearization2018In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 11, p. 1047-1049Article in journal (Refereed)
    Abstract [en]

    This letter provides a detailed analysis of the normalized mean squared error (NMSE) of an ideal orthogonal frequency-division multiplexing (OFDM) system, subject to soft clipping of the power amplifier (PA) output. Based on the central limit theorem, the OFDM baseband input is modeled as white Gaussian noise, and based on the Bussgang theorem, the NMSE is studied in some detail. Asymptotes describing the NMSE for the considered system are derived, when the system is working in the linear operation mode and when working under compression, respectively. Detailed yet simple expressions between the NMSE, average output power, saturation voltage of the PA, and the noise level of the additive channel or thermal noise are derived, which are believed to provide insight into the system's behavior.

  • 104.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    BERGENHEIM, Jon
    REMLE, Susanne
    Echo cancellation2002Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention relates to a cancellation of echoes in telecommunications systems, more specifically it relates to adaptive alignment of a linear filter (500) used for echo cancellation. According to the invention, it is continuously determined, by means of control logic (520), if a reflection replica delay included in an echo replica signal (110), which delay is provided by a signal buffer (510), should be attempted to be increased or not. Similarly, it is continuously determined if the reflection replica delay should be attempted to be decreased or not. In this way it is possible to provide a delay of the reflection replica which corresponds to the pure delay of a corresponding reflection included in an echo signal (120) received over an echo path. The invention is advantageous since the filter (500) will continuously and quickly adapt to changes in the echo path delay by continuously increasing or decreasing, in an incremental and smooth manner, a present replica delay.

  • 105.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Björsell, Niclas
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Jansson, Magnus
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Model Based Dynamic Characterization of Analog-Digital-Converters at Radio Frequency2007In: 2007 9th International Symposium on Signal Processing and its Applications, Vol. 1-3, 2007, p. 1403-1408Conference paper (Refereed)
    Abstract [en]

    A dynamic characterization of analog-digital converter integral nonlinearity (INL) is considered. When using a plurality of test frequencies in the measurement set-up, the dynamic errors of the converter are characterized. The INL is modeled by low and high code components - LCF and HCF, respectively. The LCF and HCF are parameterized and a least squares method is derived for the estimation of the parameter values from obtained measurements. A closed form solution to the estimation problem is derived and its performance is illustrated by a numerical example. The proposed method is believed to be fruitful in wide-band characterization of analog-digital converters at radio frequency, and thus of importance for the evaluation of modem and future wireless communication systems.

  • 106.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Björsell, Niclas
    University of Gävle.
    Jansson, Magnus
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Medawar, Samer
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Modeling the Dynamics of Analog-Digital Converters at Radio Frequency2007Conference paper (Refereed)
  • 107.
    Händel, Peter
    et al.
    Avdelningen för systemteknik, Uppsala universitet.
    Carlsson, Bengt
    Avdelningen för systemteknik, Uppsala universitet.
    Identifiering av termiskt nätverk1996In: Reglermöte'96, 6-7 juni 1996 i Luleå, 1996Conference paper (Refereed)
  • 108.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Enstedt, Bo
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Ohlsson, Martin
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Combating the effect of chassis squat in vehicle performance calculations by accelerometer measurements2010In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 43, no 4, p. 483-488Article in journal (Refereed)
    Abstract [en]

    The performance of a vehicle is measured as the time to complete an assigned task while accelerating. Non-intrusive performance measurements are often based on inertial navigation, i.e. measurements from an accelerometer are integrated once to obtain an estimate of the speed of the vehicle. A second integration results in a measure of the traveled distance. However, the suspension system of the vehicle introduces error in the measurements, owing to the tendency of the chassis to rise in the front and drop in the back during acceleration. An approach is derived based on the method of weighted least-squares for estimating the misalignment angle as a function of the horizontal acceleration. The proposed method includes a parametric model describing the effect of the tilt of the vehicle on the accelerometer measurements. Further. the method employs an external reference. It is shown that for a particular parametric model, the problem at hand has a closed-form solution. Certain practical applications are studied in some detail. A relative error of 0.5% in the elapsed time and 5% in the final speed is illustrated on 201-m straight track races.

  • 109.
    Händel, Peter
    et al.
    Uppsala universitet.
    Eriksson, A.
    Wigren, T.
    Performance analysis of a correlation based single tone frequency estimator1995In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 44, no 2, p. 223-231Article in journal (Refereed)
    Abstract [en]

    This paper analyzes the frequency error variance of a low complexity single tone frequency estimator based on sample correlations of the input data. In the high SNR scenario it is analytically shown that the accuracy of a properly tuned algorithm is nearly optimal, i.e. nearly attains the Cramer-Rao lower bound. For low SNR the statistical efficiency of the algorithm is degraded, but it is analytically proven that for a large number of samples the error variance attains the lower bound for this class of estimators.

  • 110.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Host-Madsen, A.
    On frequency estimation from oversampled quantized observations1999In: Acoustics, Speech, and Signal Processing, 1999. Proceedings., 1999 IEEE International Conference on, 1999, Vol. 3, p. 1549-1552Conference paper (Refereed)
    Abstract [en]

    The effect of sampling and quantization on frequency estimation for a single sinusoid is investigated. Asymptotic Cramer-Rao bounds (CRB) for 1-bit quantization and for non-ideal filters are derived, which are simpler to calculate than the exact CRB while still relatively accurate. It is further investigated how many bits should be used in quantization to avoid the problems of 1-bit quantization, and it turns out that 3-4 bits are enough. Finally, oversampled 1-bit quantization is investigated. It is determined how much the signal should be oversampled, and in addition Sigma; Delta; modulators are investigated

  • 111.
    Händel, Peter
    et al.
    Tampere Univ. of Technol. .
    Host-Madsen, A.
    Particle velocity and size estimation from two channel laser anemometry measurements1997In: Acoustics, Speech, and Signal Processing, 1997. ICASSP-97., 1997 IEEE International Conference on, 1997, Vol. 5, p. 3529-3532Conference paper (Refereed)
    Abstract [en]

    A mathematical treatment of particle size and velocity estimation from two channel laser anemometry measurements is considered. Cramer-Rao bounds for the general case are derived, and the corresponding maximum likelihood estimator is analyzed through computer simulations. Low complexity correlation based estimators are derived and their performance is characterized. The results predicted by theory are illustrated by some numerical examples

  • 112.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Host-Madsen, Anders
    Estimation of velocity and size of particles from two channel laser anemometry measurements1997In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 21, no 3, p. 113-123Article in journal (Refereed)
  • 113.
    Händel, Peter
    et al.
    Tampere University of Technology.
    Kiss, Imre
    Signal Processing Laboratory, Tampere University of Technology.
    On correlation based single tone frequency estimation1997In: 1997 Finnish Signal Processing Symposium, May 22, 1997, Pori, Finland, 1997, p. 32-36Conference paper (Refereed)
    Abstract [en]

    The single tone frequency estimation problem is studied.Starting  with the maximum likelihood estimator and anassumption on high SNR, a generic estimator utilizinga sequence of estimated correlations is derived.Its relation to several existing estimators isgiven, and an expression for its asymptotic errorvariance is derived.Simulation results which lend support to thetheoretical findings are included.

  • 114.
    Händel, Peter
    et al.
    Uppsala Universitet.
    Nehorai, A.
    Tracking analysis of a constrained adaptive notch filter1991In: Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on, 1991, p. 3209-3212Conference paper (Refereed)
    Abstract [en]

    The asymptotic tracking properties of an adaptive notch filter with pole-zeros constraints for the cancellation or retrieval of multiple time-varying sine waves in additive noise are analyzed. The methods of Ljung and Gunnarsson (see Automatica, vol.26, no.1, p.7-21, Jan. 1990) are used in order to analyze the asymptotic mean-square parameter error, when the variations in the underlying frequencies and the gain of the algorithm are assumed to be sufficiently small. A closed-form expression for the mean square error (MSE) is derived as a function of the tuning variables of the algorithm. The results give insight into the operational properties of the algorithm and are used in order to minimize the MSE with respect to the tuning variables

  • 115. Händel, Peter
    et al.
    Nehorai, A.
    Tracking analysis of an adaptive notch filter with constrained poles and zeros1994In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 42, no 2, p. 281-291Article in journal (Refereed)
    Abstract [en]

    This paper analyzes the asymptotic tracking properties of an adaptive notch filter (ANF) with pole-zero constraints [1] for the cancellation or retrieval of multiple time-varying sine waves in additive noise. The asymptotic mean square error (MSE) is analyzed using the methods of Ljung and Gunnarsson [2] when the variations in the underlying frequencies are assumed to be sufficiently small. Closed-form expressions for the MSE are derived as functions of the tuning variables of the algorithm. The results give insight into the operational properties of the algorithm and are used in order to minimize the MSE with respect to the tuning variables. Computer simulations confirm the validity of the derived results.

  • 116.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. Movelo AB, Sweden.
    Ohlsson, Jens
    Stockholm University.
    Ohlsson, Martin
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. Movelo AB, Sweden.
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. Movelo AB, Sweden.
    Nygren, Elin
    Smartphone-Based Measurement Systems for Road Vehicle Traffic Monitoring and Usage-Based Insurance2014In: IEEE Systems Journal, ISSN 1932-8184, E-ISSN 1937-9234, Vol. 8, no 4, p. 1238-1248Article in journal (Refereed)
    Abstract [en]

    A framework is presented to deploy a smartphone-based measurement system for road vehicle traffic monitoring and usage-based insurance (UBI). Through the aid of a hierarchical model to modularize the description, the functionality is described as spanning from sensor-level functionality and technical specification to the topmost business model. The designer of a complex measurement system has to consider the full picture from low-level sensing, actuating, and wireless data transfer to the topmost level, including enticements for the individual smartphone owners, i.e., the end users who are the actual measurement probes. The measurement system provides two data streams: a primary stream to support road vehicle traffic monitoring and a secondary stream to support the UBI program. The former activity has a clear value for a society and its inhabitants, as it may reduce congestion and environmental impacts. The latter data stream drives the business model and parts of the revenue streams, which ensure the funding of the total measurement system and create value for the end users, the service provider, and the insurance company. In addition to the presented framework, outcome from a measurement campaign is presented, including road vehicle traffic monitoring (primary data stream) and a commercial pilot of UBI based on the driver profiles (secondary data stream). The measurement system is believed to be sustainable due to the incitements offered to the individual end users, in terms of favorable pricing for the insurance premium. The measurement campaign itself is believed to have an interest in its own right, as it includes smartphone probing of road traffic with a number of probes in the vicinity of the current state of the art, given by the Berkeley Mobile Millennium Project. During the ten-month run of the project, some 4500 driving h/250 000 km of road vehicle traffic data were collected.

  • 117.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Ohlsson, Martin
    Enstedt, Bo
    Kompensation av accelerometermätning2005Patent (Other (popular science, discussion, etc.))
  • 118.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Martin
    Ohlsson, Jens
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Avläsning och central lagring av mätarställning2012Patent (Other (popular science, discussion, etc.))
  • 119.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Martin
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Jens
    Bestämning av aktivitetsgrad hos portabel elektronisk utrustning2012Patent (Other (popular science, discussion, etc.))
  • 120.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Martin
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Jens
    Determination of activity rate of portable electronic equipment2012Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A method for obtaining activity rate of a portable electronic device (250) during travel with a vehicle (200) comprises determining (S100) a calculated driving distance based on the portable electronic device utilizing a sequence of measured positions for the portable electronic device. The method further comprises determining (S200) a read driving distance by reading of odometer indication (270) of the vehicle. The method also comprises calculating (S300) an activity rate by comparison of the calculated driving distance with the read driving distance. The method further comprises calculating (S400) a flag which indicates the validity of the calculated activity rate, where the flag is calculated based on the sequence of measured positions for the portable electronic device. The method also comprises transferring (S500) an information packet (280) to a central server (290), where the information packet comprises the activity rate, and/or the read driving distance, and/or the flag.

  • 121.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Ottoson, Ragnar
    Hjalmarsson, Håkan
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Signalteori2004 (ed. 3)Book (Other (popular science, discussion, etc.))
  • 122.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    PETTERSSON, Mikael
    SKOGLUND, Mikael
    METHOD AND SYSTEM FOR CALIBRATING ANALOG-TO-DIGITAL CONVERSION2000Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A method and system enables ADCs to be calibrated from reference signals with unknown parameters. A given analog reference signal (i(s)(i(t))) is suplied to an ADC (310). The output (i(x)(i(k))) of the ADC (310) is used by calibration logic (320) to estimate at least one parameter of the reference signal (i(s)(i(t))). A FIR filter (455) accepts as input the i(x)(i(k)) signals and outputs an estimate (ŝ(i(k))) as the sampled instances of the i(s)(i(t)) signal. A reconstruction table (So,...,SM-1) is created that approximates the analog input signal in the digital domain using the knowledge of the analog input signal waveform type. The actual ADC outputs (i(x)(i(k))) are compared to the values in the reconstruction table (So,...,SM-1) to produce a correction table (350) for calibration. A continuous time reference signal may be utilized for training the correction table (350). The method and system is data adaptive, so it may be applied, for example, with any sinusoidal reference input.

  • 123.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Prasad, Sathyaveer
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Beckman, Claes
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Maximum likelihood estimation of reverberation chamber direct-to-scattered ratio2009In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 45, no 25, p. 1285-U24Article in journal (Refereed)
    Abstract [en]

    The exact maximum likelihood estimator of the direct-to-scattered ratio of the Rician channel in a reverberation chamber is derived and its performance analysed. It is shown that the estimator obeys a non-central F-distribution, the mean value and variance of which are derived. For well stirred chambers, it is shown that the systematic error in the estimated ratio may be significant.

  • 124.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    RASMUSSON, Jim, Agne, Jerker
    Methods and apparatus for measuring signal level and delay at multiple sensors1997Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Methods and apparatus for automatic gain and time delay computations between multiple sensors. In exemplary embodiments, one sensor is treated as a reference sensor with respect to a measured signal quantity which is assumed to be a narrowband process. The relative gain and relative time delay in the additional sensors with respect to the same measured quantity are then automatically calculated based on an adaptive filtering algorithm. Advantageaously, the disclosed embodiments are implemented using standard digital signal processing components.

  • 125.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Ronnow, Daniel
    Univ Gavle, Dept Elect Math & Nat Sci, S-80176 Gavle, Sweden..
    Dirty MIMO Transmitters: Does It Matter?2018In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 8, p. 5425-5436Article in journal (Refereed)
    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.

  • 126.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Martin
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, J.
    Smartphone instrumentation for insurance telematics2015In: Conference Record - IEEE Instrumentation and Measurement Technology Conference, IEEE Press, 2015, Vol. July, p. 1613-1616Conference paper (Refereed)
    Abstract [en]

    Insurance telematics is a disruptive technology that is expected to reform the vehicle insurance industry. Based on sensor data, the traditional measures for calculating the insurance premium are complemented to determine a fee that more accurately predicts the risk profile of the policyholder. From an instrumentation and measurement point of view, there are several insurance telematics challenges that have to be tackled. It is about consistently extracting relevant figures of merit (FoMs) like number of harsh braking, speeding, heavy cornering, trip smoothness, etc, and then to transform these FoMs into a valid measure, or score, that determines the risk profile of the insurance customer. The paper presents a characterization of FoMs in terms of actuarial relevance, the driver’s influence, stationarity and observability, which are important for the given task. Dedicated hardware to be fitted into the on-board diagnostics outlet as well as contemporary smartphones are two different insurance telematics platforms for data collection. The paper discusses the properties of the smartphone in the perspective of insurance telematics as a low-cost alternative to the hardwired platforms like the one connected to the vehicle’s on-board diagnostics outlet.

  • 127. Händel, Peter
    et al.
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Ohlsson, Martin
    Ohlsson, Jens
    Anordning för att bestämma identitet hos ett motorfordon2012Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A device (100) for determining an identity of a vehicle comprises a connector (110) configured to be connected to the cigarette lighter outlet (230) of the vehicle (200). The device further comprises measuring equipment (310; 320; 330) configured to provide an electric signal (400) related to the engine speed of the vehicle, such that oscillations in the electric signal have a frequency proportional to the engine speed of the vehicle. The device is configured to allow determination of an identity of the vehicle based on the electric signal, such that the identity is independent of variations in the engine speed of the vehicle. The device also comprises a memory (340) configured to store the electric signal, and/or the identity of the vehicle.

  • 128.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Skog, Isaac
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Wahlström, Johan
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Bonawiede, Farid
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Welch, R.
    Ohlsson, J.
    Ohlsson, Martin
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Insurance telematics: Opportunities and challenges with the smartphone solution2014In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 6, no 4, p. 57-70, article id 6936433Article in journal (Refereed)
    Abstract [en]

    Smartphone-based insurance telematics or usage based insurance is a disruptive technology which relies on insurance premiums that reflect the risk profile of the driver; measured via smartphones with appropriate installed software. A survey of smartphone-based insurance telematics is presented, including definitions; Figure-of-Merits (FoMs), describing the behavior of the driver and the characteristics of the trip; and risk profiling of the driver based on different sets of FoMs. The data quality provided by the smartphone is characterized in terms of Accuracy, Integrity, Availability, and Continuity of Service. The quality of the smartphone data is further compared with the quality of data from traditional in-car mounted devices for insurance telematics, revealing the obstacles that have to be combated for a successful smartphone-based installation, which are the poor integrity and low availability. Simply speaking, the reliability is lacking considering the smartphone measurements. Integrity enhancement of smartphone data is illustrated by both second-by-second lowlevel signal processing to combat outliers and perform integrity monitoring, and by trip-based map-matching for robustification of the recorded trip data. A plurality of FoMs are described, analyzed and categorized, including events and properties like harsh braking, speeding, and location. The categorization of the FoMs in terms of Observability, Stationarity, Driver influence, and Actuarial relevance are tools for robust risk profiling of the driver and the trip. Proper driver feedback is briefly discussed, and rule-of-thumbs for feedback design are included. The work is supported by experimental validation, statistical analysis, and experiences from a recent insurance telematics pilot run in Sweden.

  • 129.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Andersson, Tomas
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Höst-Madsen, Anders
    Method and apparatus for estimating physical parameters in a signal2000Patent (Other (popular science, discussion, etc.))
  • 130.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    SKOGLUND, Mikael
    LUNDIN, Henrik
    Adaptively calibrating analog-to-digital conversion with correction table indexing2000Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Methods, systems, and arrangements enable true wide-band calibration of analog-to-digital conversion (ADC) using correction table indexing (350, 660). The frequency of an analog input signal that corresponds to a digital output sample is accounted for, at least partially, when accessing a correction table (350, 660) during the creation and use thereof. For example, in addition to at least a portion of a current sample, at least portion(s) of previous and/or subsequent samples may be used to build (805) (e.g., by bit concatenation) an index for addressing a correction table memory. In effect, compensation may be achieved for ADC errors that are frequency dependent. This correction table (350; 660) indexing may advantageously be employed along with a scheme that estimates (1020A) one or more parameters of the analog input signal in the digital domain on a sample-by-sample basis in order to reconstruct the analog input signal in the digital domain.

  • 131.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Pettersson, M.
    A calibration scheme for imperfect quantizers2000In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 49, no 5, p. 1063-1068Article in journal (Refereed)
  • 132.
    Händel, Peter
    et al.
    Uppsala universitet.
    Stoica, P.
    Soderstrom, T.
    Capon method for doa estimation accuracy and robustness aspects1993In: Nonlinear Digital Signal Processing, 1993. IEEE Winter Workshop on, 1993, p. P.7.1-P.7.5Conference paper (Refereed)
  • 133.
    Händel, Peter
    et al.
    Uppsala universitet.
    Stoica, P.
    Söderström, T.
    Asymptotic variance of the AR spectral estimator for noisy sinusoidal data1994In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 35, no 2, p. 131-139Article in journal (Refereed)
    Abstract [en]

    In this paper the autoregressive (AR) spectral estimator is analyzed in the case of noisy sinusoidal data. An expression for the large-sample normalized variance is derived and studied in detail for increasing model order. In particular, a very simple formula is derived for the asymptotic (in both number of observed data and model order) normalized variance, which confirms a conjecture made by Sakai.

  • 134.
    Händel, Peter
    et al.
    Uppsala universitet.
    Tichavsky, P.
    Adaptive estimation for periodic signal enhancement and tracking1994In: International journal of adaptive control and signal processing (Print), ISSN 0890-6327, E-ISSN 1099-1115, Vol. 8, no 5, p. 447-456Article in journal (Refereed)
    Abstract [en]

    A fast algorithm for enhancement and tracking of periodic signals with fixed or slowly varying central frequency in additive noise is proposed. The algorithm is based on results from discounted least squares identification of a harmonic signal model combined with a recursive update scheme for the estimated fundamental frequency. In particular the gain sequence of the algorithm is determined by the fundamental frequency and an eligible forgetting factor. The performance of the algorithm is compared with theoretical lower bounds and it is shown that the algorithm yields good results.

  • 135.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Tichavsky, P.
    Asymptotic noise gain of polynomial predictors1997In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 62, no 2, p. 247-250Article in journal (Refereed)
    Abstract [en]

    Finite impulse response filters for the prediction of polynomial signals are considered. An expression for the asymptotic noise gain (as the filter length increases without bound) is derived. It is shown that the asymptotic noise gain only depends on the polynomial order - in particular, it is independent of the prediction horizon. It is also shown that the noise gain forms a non-increasing sequence for increasing filter lengths. Numerical results that lend support to the theoretical findings are included.

  • 136. Händel, Peter
    et al.
    Tichavsky, P.
    Frequency rate estimation at high SNR1997In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 45, no 8, p. 2101-2105Article in journal (Refereed)
    Abstract [en]

    The problem of estimating the frequency rate-of-change of complex-valued frequency-modulated signals from noisy observations is considered. The performance of four related estimators is studied, both analytically and by means of simulations, and their relationship to the estimators proposed by Djuric/Kay and Lang/Musicus is established.

  • 137.
    Händel, Peter
    et al.
    Uppsala universitet.
    Tichavsky, P.
    Frequency rate estimation based on fourth order sample moments1996In: 8th IEEE Signal Processing Workshop on Statistical Signal and Array Processing, SSAP'96, 1996, p. 391-394Conference paper (Refereed)
    Abstract [en]

    Estimation of the frequency rate of linear frequency modulated signals based on phase angles of fourth order sample moments is considered. Three low-complexity estimators are proposed whose performance is close to optimal, that is their error variance is close to the Cramer-Rao lower bound

  • 138.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Tichavsky, P.
    Savaresi, S. M.
    Large error recovery for a class of frequency tracking algorithms1998In: International journal of adaptive control and signal processing (Print), ISSN 0890-6327, E-ISSN 1099-1115, Vol. 12, no 5, p. 417-436Article in journal (Refereed)
    Abstract [en]

    The performance of a recently proposed high-order adaptive notch filter (HANF) for frequency estimation and tracking is studied. An analysis technique utilizing approximations with linear filters is employed to derive closed-form performance expressions for a noisy sinusoidal input signal. Important performance measures, such as stability, noise rejection, statistical efficiency, and tracking ability, are studied in detail, and rules for the design variables are given. A study is presented where the performance of HANF is compared with the performance of a minimal order adaptive notch filter (ANF), as well as with a frequency tracker based on least squares-modelling-the multiple frequency tracker (MFT). The study reveals that HANF is a competitive alternative to ANF, but also that, in general, the MFT is the method of choice.

  • 139.
    Händel, Peter
    et al.
    Tampere University of Technology.
    Tichavsky, Petr
    Academy of Sciences of the Czech Republic.
    Savaresi, Sergio M
    Dipartimento di Elettronica e Informazione, Milano, Italy.
    Performance analysis of a constrained high-order adaptivenotch filter1997In: 1997 Finnish Signal Processing Symposium, May 22, 1997, Pori, Finland, 1997, p. 21-24Conference paper (Refereed)
    Abstract [en]

    The performance of a recently proposedhigh order adaptive notch filter (HANF)for frequency estimation and tracking is studied.An analysis technique utilizing approximations with linearfilters is employed in order toderive closed form performance expressionsfor a noisy sinusoidal input signal.  Importantperformance measures, such as stability, noise rejection,statistical efficiency,and tracking ability, are studied in detail, andrules for the design variables are given.

  • 140.
    Händel, Peter
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Volcker, B.
    Goransson, B.
    Analysis of a simple, effective frequency estimator based on Prony’s method1998In: Statistical Signal and Array Processing, 1998. Proceedings., Ninth IEEE SP Workshop on, 1998, p. 316-319Conference paper (Refereed)
    Abstract [en]

    In a recent paper by Tufts and Fiore (1996) a low-complexity frequency estimator based on Prony’s method was proposed. The estimate is formed from two sample correlations r circ;(L1) and r circ;(L2), where 1 les;L1 les;L2 les;N-1 and N is the number of samples. For a correct phase unwrapping it is required that L1 and L2 are relatively prime. In this paper, a slight modification of the original algorithm is presented, and an expression for its asymptotic variance is derived. It is shown that the error variance is minimized for L1=3N/5 and L2=4N/5 for which the quotient of the error variance and the Cramer-Rao bound tends to 25/24 ap;1.042. Suboptimal settings of L1 and L2 are shown to exist, resulting in a lowered SNR-threshold while retaining the asymptotic efficiency. Simulation results which lend support to the theoretical findings are included

  • 141.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Yao, Yi
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Unkuri, Nina
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skog, Isaac
    Far infrared camera platform and experiments for moose early warning systems2009In: Transactions of Society of Automotive Engineers of Japan, ISSN 0287-8321, Vol. 40, no 4, p. 1095-1099Article in journal (Refereed)
    Abstract [en]

    Encounters between big game, such as the moose, and private cars often result in severe injuries and death. A vehicle-based moose detection early warning system is a technical countermeasure to increase the traffic safety by alerting the driver in case of danger. Based on available off-the-shelf consumer electronics, a infrared night vision system was built to serve as a platform for experiments with moose early warning driver assistance systems. Aspects of a moose thermal replica employing a horse are discussed and typical vehicle-moose movements are directed and recorded to form a publicly available database for research and education.

  • 142.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Zetterberg, Per
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Investigating the USRP: I/Q imbalance2009Conference paper (Other academic)
  • 143.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Zetterberg, Per
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Measuring demodulator imbalance in radio frequency receivers by tone test2009In: 19th IMEKO World Congress 2009, 2009, p. 462-465Conference paper (Refereed)
    Abstract [en]

    The measurement of in-phase/quadrature (IQ) imbalance parameters of radio frequency direct downconversion receivers by tone test is considered. The receiver is excited by a radio frequency sinewave, and the digital baseband output is used as the sole basis for the determination of the IQ imbalance parameters, which are the gain imbalance, quadrature skew and local oscillator leakage. A set of parameters is estimated from the baseband output of the direct downconversion receiver and the required parameters are then calculated by a transformation. The universal software radio peripheral (USRP) is a widespread hardware for research, education, and development regarding future wireless communication receivers. A set of USRPs are tested. It is shown that for the receivers studied, gain imbalance and quadrature skew may be predicted accurately (that is, < 0.1 dB and < 1 deg, respectively) by employing baseband data covering a handful of full periods of the excitation stimuli. The work also shows that local oscillator leakage may suffer from systematic bias error of the order of 15 dB. To obtain leakage estimates with an uncertainty in the order of one dB, the measurement time has to be increased by two orders of magnitude.

  • 144.
    Händel, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Zetterberg, Per
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Receiver I/Q Imbalance: Tone Test, Sensitivity Analysis, and the Universal Software Radio Peripheral2010In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 59, no 3, p. 704-714Article in journal (Refereed)
    Abstract [en]

    The problem of determining the gain imbalance, quadrature skew, and local oscillator leakage of contemporary radio frequency receivers by tone test is considered. A least squares approach for indirect estimation of the sought-for parameters is proposed, which is linear in six out of its seven parameters. The performance of the method, particularly its accuracy as a function of measurement time, imbalance parameters, and signal-to-noise ratios, is investigated. The theoretical predictions of the performance are illustrated by Monte Carlo simulations and experimental data that are obtained from testing several universal software radio peripheral (USRP) receivers. This paper shows that, for the studied off-the-shelf receivers, gain imbalance and quadrature skew may accurately be predicted (i.e., < 0.1 dB and < 1 degrees, respectively) by employing baseband data covering only a handful of full periods of the excitation stimuli. Using short records of data, this paper also shows that local oscillator leakage adding a bias term in the receiver baseband data may suffer from a systematic bias error on the order of 15 dB in the estimate. To obtain local oscillator leakage estimates with an uncertainty on the order of 1 dB, the measurement time has to be increased by two orders of magnitude.

  • 145.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. University of Gävle, Sweden .
    Efrain, Zenteno
    KTH, School of Electrical Engineering (EES), Signal Processing. University of Gävle, Sweden .
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Isaksson, Magnus
    Högskolan i Gävle.
    Study of the Power Amplifier transfer function symmetry and its relation to dynamic effects2015Conference paper (Refereed)
    Abstract [en]

    Future wireless networks will employ unprecedentedly high number of transmitters along-with larger bandwidth signals. Therefore, complexity efficient Power Amplifier (PA) modelling methods with the ability to quantify memory effects are required. This paper presents a low complexity method to quantify memory effects by studying the symmetry in the PA transfer functions estimated with the density estimation method. It is shown that the symmetry helps in reducing the method complexity by more than two orders of magnitude. Further, it is verified that the symmetry can be used as a non-model based metric for quantifying memory effects in PAs.

  • 146.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering (EES), Information Science and Engineering. Högskolan i Gävle.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Information Science and Engineering.
    Isaksson, Magnus
    Högskolan i Gävle.
    A Comparative Analysis of the Complexity/Accuracy Tradeoff in the Mitigation of RF MIMO Transmitter Impairments2017In: 89th ARFTG Microwave Measurement Conference: Advanced Technologies for Communications, ARFTG 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 8000827Conference paper (Refereed)
    Abstract [en]

    This paper presents a comparative analysis of the complexity accuracy tradeoff in state-of-the-art RF MIMO transmitter mitigation models. The complexity and accuracy of the candidate models depends on the basis functions considered in these models. Therefore, a brief description of the mitigation models is presented accompanied by derivations of the model complexities in terms of the number of FLOPs. Consequently, the complexity accuracy tradeoff in the candidate models is evaluated for a 2 × 2 RF MIMO transmitter. Furthermore, the model complexities are analyzed for increasing nonlinear orders and number of antennas.

  • 147.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing. Högskolan i Gävle.
    Zenteno, Efrain
    Universidad Católica San Pablo.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Isaksson, Magnus
    Högskolan i Gävle.
    Digital Predistortion for Joint Mitigation of I/Q Imbalance and MIMO Power Amplifier Distortion2016In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, no 99, p. 1-12Article in journal (Refereed)
    Abstract [en]

    This paper analyzes the joint effects of in-phase and quadrature (I/Q) imbalance and power amplifier (PA) distortion for RF multiple input multiple output (MIMO) transmitters in the presence of crosstalk. This paper proposes candidate models for the digital predistortion of static I/Q imbalanced sources exciting a dynamic MIMO Volterra system. The proposed models are enhanced using a novel technique based on subsample resolution to account for dynamic I/Q imbalance distortions. Finally, the computational complexity of the proposed models is analyzed for implementation suitability in digital platforms. It is shown that the error spectrum for the proposed models in subsample resolution reaches the noise floor of the measurements. The proposed models achieve a normalized mean squared error of -50 dB and an adjacent channel power ratio of -57 dB for signal bandwidths upto 65 MHz and crosstalk levels ranging to -10 dB. These results demonstrate the effectiveness of the proposed techniques in the joint mitigation of I/Q imbalance and PA distortion with crosstalk for a typical 2x2 MIMO telecommunication setup.

  • 148.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Zenteno, Efrain
    Universidad Católica San Pablo.
    Händel, Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Isaksson, Magnus
    University of Gävle.
    Extraction of the Third-Order 3x3 MIMO VolterraKernel Outputs Using Multitone Signals2018In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 66, no 11, p. 4985-4999Article in journal (Refereed)
    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.

  • 149.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering. Högskolan i Gävle.
    Zenteno, Efrain
    Universidad Católica San Pablo.
    Händel, Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering. KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems.
    Isaksson, Magnus
    Högskolan i Gävle.
    Identification of Third Order 3x3 MIMO Volterra Kernels using Multitone Excitation SignalsManuscript (preprint) (Other academic)
  • 150.
    Khan, Zain Ahmed
    et al.
    KTH, School of Electrical Engineering (EES), Information Science and Engineering. Universidad Catolica San Pablo, Peru.
    Zenteno, Efrain
    Dept. Electronics and Telecommunications, Universidad Catolica San Pablo, Arequipa, Peru.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Information Science and Engineering.
    Isaksson, Magnus
    Dept. Electronics, Mathematics, and Natural Sciences, University of Gävle, Gävle, Sweden.
    Multitone design for third order MIMO volterra kernels2017In: 2017 IEEE MTT-S International Microwave Symposium (IMS), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1553-1556, article id 8058925Conference paper (Refereed)
    Abstract [en]

    This paper proposes a technique for designing multitone signals that can separate the third order multiple input multiple output (MIMO) Volterra kernels. Multitone signals fed to a MIMO Volterra system yield a spectrum that is a permutation of the sums of the input signal tones. This a priori knowledge is used to design multitone signals such that the output from the MIMO Volterra kernels does not overlap in the frequency domain, hence making it possible to separate these kernels from the output of the MIMO Volterra system. The proposed technique is applied to a 2×2 RF MIMO transmitter to determine its dominant hardware impairments. For input crosstalk, the proposed method reveals the dominant self and cross kernels whereas for output crosstalk, the proposed method reveals that only the self kernels are dominant.

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