Torbjörn Wigren
Visiting researcher at Department of Information Technology; Division of Systems and Control
- Telephone:
- +46 18 471 54 20
- Mobile phone:
- +46 70 267 19 82
- E-mail:
- Torbjorn.Wigren@it.uu.se
- Visiting address:
- Hus 10, Lägerhyddsvägen 1
- Postal address:
- Box 337
751 05 UPPSALA
- ORCID:
- 0000-0003-2580-8906
More information is available to staff who log in.
Short presentation
My research is focused on nonlinear systems, in particular recursive system identification and constrained optimal control. Time delay and stability analysis are other related areas of interest.
Biography
This text is not available in English, therefore the Swedish version is shown.
Torbjörn Wigren (IEEE ,S'89-M'91-SM'98) was born in Mora, Sweden, in 1961. He received the M.Sc. degree (Engineering Physics) and the Dr. of Technology degree (Automatic Control) from Uppsala University , Uppsala, Sweden, in 1985 and 1990, respectively. Currently, he holds a position as Principal Development Leader at Ericsson AB, where he is responsible for feedback control in cellular 4G and 5G systems.
His industrial experience includes research and development work for several major Swedish companies. He was with Bofors Aerotronics AB 1985-1991, working on image processing, fire control and management of a group with that responsibility. During 1989 and 1990 he was with the Systems and Control Group, Uppsala University, completing his Tekn. Dr. degree. That work was focused on nonlinear and recursive system identification, in particular algorithm development and convergence analysis. At Ericsson AB's R&D-division (1991-1995), voice signal processing department, main tasks included work on the half-rate voice-codecs for the North American cellular TDMA system, as well as for the GSM system. He also worked on acoustic echo control for handsfree. In 1995, he moved to CelsiusTech Systems AB, switching to the data fusion field, with a focus on target type estimation for multi-sensor air surveillance systems. From 1999 to 2001 he developed and adapted multi sensor fusion technology for automotive applications at CelsiusTech Electronics AB. In 2001, he returned to Ericsson Radio Systems AB to work with third generation cellular telephony, in particular development and standardization of technology for cellular location estimation. Other tasks included the design and software development of soft load estimation algorithms for scheduling of WCDMA enhanced uplink channels. He was given the Ericsson Inventor of the Year Award for 2007 for this work, and for contributions to fingerprinting location technology. In 2010-2012 he was recognized as a key contributor to Ericsson AB. In 2014, he took up a position within Ericsson's 5G organization, to work on signal processing and control for 5G radios. He received the Ericsson Impact Award in 2018 for his work. In 2000 he was appointed an adjunct Professor of Automatic Control at the Department of Information Technology, Uppsala University, Sweden, sponsored by Ericsson AB. Between 2006 and 2012 he held a position as adjunct Professor of Systems Modeling, at the same institution. During 2012-2018 he was again adjunct Professor of Automatic Control at Uppsala University, where he is currently a guest researcher. His academic research interests include nonlinear techniques for recursive identification, estimation and control, in particular applied to biodiversity modeling, delays in cybersecure control systems, and constrained optimal control.
Curriculum Vitae
Education
Doctor of Technology, Automatic Control, Uppsala Univ..............90-12-07
Master of Science, Engineering Physics (EE), Uppsala Univ........85-06-20
Academic Employment
Guest Researcher....................................................................................18-08-01-
Adjunct Professor, Automatic Control, Uppsala Univ....12-08-01-18-06-30
Adjunct Professor, Systems Modeling, Uppsala Univ....06-07-01-12-06-30
Docent in Electrical Engineering, Uppsala Univ.....................................02-02
Adjunct Professor, Automatic Control, Uppsala Univ...00-04-01-06-03-31
Industrial Employment
Principal development leader, Ericsson AB, radio algorithms.....22-12-12-
Principal developer, Ericsson AB, RRM LTE and NR........21-11-01-22-12-12
Systems engineer, Ericsson AB, LTE and 5G L1, L2........14-09-01-21-10-31
Senior specialist, Ericsson AB, wideband radio................10-10-19-11-12-31
Systems engineer, Ericsson AB, wideband radio...........09-08-01-10-10-18
Systems engineer, Ericsson AB, wideband navigation..01-03-19-09-07-31
Staff scientist, SAABTech Electronics AB, car radar......99-11-15-01-02-17
Staff scientist, CelsiusTech Systems AB, sensor fusion.95-05-16-99-11-15
Researcher, Ericsson Radio Systems AB, audio techn...91-02-18-95-05-13
Manager, Bofors Aerotronics AB, fire control systems..90-08-01-91-02-15
Manager, Bofors Aerotronics AB, image processing........88-01-01-88-12-31
Engineer, Bofors Aerotronics AB, fire control systems..85-08-05-87-12-31
Memberships
Member IEEE...................................................................................................1991-
Member AIAA.................................................................................................2000-
Awards
Ericsson Impact Award 2018...............................................................19-03-04
Automatica Outstanding Reviewer 2010-2011.................................13-05-01
Ericsson Key Contributor 2012...........................................................12-05-23
Ericsson Key Contributor 2011............................................................11-05-27
Ericsson Key Contributor 2010...........................................................10-05-20
Senior Member AIAA............................................................................09-03-01
Ericsson Inventor of the Year 2007...................................................07-11-28
DARPA Coin 505....................................................................................03
Senior Member IEEE...........................................................................98-06-27
Research
This text is not available in English, therefore the Swedish version is shown.
Google Scholar
Active Research Projects
Networked recursive identification of nonlinear systems
Recursive identification of non-linear systems using differential equation models
Delay attack and detection in cyber secure feedback control systems
Completed Research Projects
Automatic Control
Integration of feedback and feed-forward techniques in reinforcement learning
Scheduling and power control for cellular radio systems
Fundamental low frequency limitations in networked control
Networked control with saturation and delay
Linearizing control of non-linear Wiener systems
Estimation
Passive state estimation of air vehicles
Location technology for wireless systems
Wideband interference estimation and advanced receivers
Signal Processing
Sensor array and narrowband signal processing
Speech coding, audio signal processing, echo cancellation and source separation
System Identification
Identification and estimation using quantized output signal measurements
Non-linear system identification in systems biology
Recursive identification of nonlinear Wiener systems
Non-linear identification of periodic signals
Global convergence of blind adaptation algorithms
Applications
Average power control for RF EMF
Stability based ammonium control in waste water treatment
Identification and control of selective catalytic reduction systems
Non-linear identification and adaptive control in anaesthesia
Identification and control of non-linear solar collector plants with varying delay
Grants
1. Partner investigator (G. Goodwin chief investigator), "Power Control and Scheduling for Cellular Communications", University of Newcastle and Ericsson AB, Australian Research Council (Canberra, Australia) grant LP0989757/247035, January 2009 to December 2011.
2. Investigator (P. Stoica chief investigator), "Systems and signals tools for estimation and analysis of mathematical models in endocrinology and neurology, Uppsala University, European Research Council (Brussels, Europe, Belgium), 2010 to 2015.
3. Partner investigator (R. Middleton chief investigator), "Scheduling and quality of service in Long Term Evolution telecommunications", University of Newcastle and Ericsson AB, Australian Research Council (Canberra, Australia) grant LP120200321, January 2012 to December 2015.
4. Investigator (A. Medvedev chief investigator), "Mathematical modeling, analysis and estimation in endocrine systems with pulse-modulated feedback", Swedish research council (Vetenskapsrådet, Stockholm, Sweden), 2013 to 2015.
5. Partner investigator (R. Middleton chief investigator), "Integrated feedback control in future wireless communication networks", University of Newcastle and Ericsson AB, Australian Research Council (Canberra, Australia) grant LP150100757, January 2015 to December 2017.
PhD students
1 (Lic). Emad Abd-El Rady, "Harmonic signal modeling based on the Wiener model structure", Licentiate of Technology Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, May 14, 2002.
1. (PhD) Emad Abd-El Rady,"Nonlinear approaches to periodic signal modeling", Ph.D. Thesis, Divison of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, January 26, 2005.
2. (Lic) Linda Brus,"Recursive Black--box Identification of Nonlinear State-space Models", Licentiate of Technology Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, January, 2006.
2. (PhD) Linda Brus, "Nonlinear Identification and Control with Solar Energy Applications", Ph.D. Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, April 25, 2008.
3. (Lic) Soma Tayamon, "Nonlinear system identification with applications to selective catalytic reduction systems", Licentiate of Technology Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, June, 2012.
4. (Lic) Margarida Martins da Silva, "System identification and control for general anesthesia based on parsimonious Wiener models", Licentiate of Technology Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, October, 2012.
3. (PhD) Soma Tayamon, "Nonlinear system identification and control applied to selective catalytic reduction systems", Ph.D. Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, September, 2014.
4. (PhD) Margarida Martins da Silva, "Nonlinear modeling and feedback control of drug delivery in Anesthesia", Ph.D. Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, November, 2014.
5. (Lic) Tatiana Chistiakova, "Ammonium based aeration control in wastewater treatment plants - modelling and controller design", Licentiate of Technology Thesis, Division of Systems and Control, Department of Information Technology, Uppsala University, Uppsala, Sweden, April, 2018.
6. Ruoqi Zhang, ongoing.
7. Ville Kjellqvist, ongoing.
8. Isabella Rudengren, from 2025.
Recent Work
1. S. Yasini and T. Wigren, "Round trip time based UAV state estimation", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 3776-3782, 2024.
2. T. Wigren and A. Teixeira, "Delay attack and detection in feedback linearized control systems", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 1569-1576, 2024.
3. T. Wigren, "Convergence in delayed recursive identification of nonlinear systems", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 914-921, 2024.
4. T. Wigren, "Logarithmic feedback control of passive interference", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 154-161, 2024.
List of Publications
Book Chapters
(B1) G. C. Goodwin, K. Lau, M. Cea and T. Wigren, "Control Challenges in Mobile Telecommunications" - in The Impact of Control Technology IEEE Control Systems Society, 2011. Available at http://ieeecss.org/main/IoCT-report .
(B2) A. Kangas, I. Siomina and T. Wigren, "Positioning in LTE" - in S. A. Zekavat and R. M. Buehrer (eds.), Handbook of Position Location: Theory, Practice and Advances. Hoboken, NJ: Wiley, 2012.
(B3) G. C. Goodwin, M. Cea, K. Lau and T. Wigren, "Control challenges in Mobile Telecommunications" - in "The Impact of Control Technology - 2nd Ed.", IEEE Control Systems Society, 2014. Available at http://ieeecss.org/general/IoCT2-report.
(B4) A. Kangas, I. Siomina and T. Wigren, "Positioning in LTE" - in S. A. Zekavat and R. M. Buehrer (eds.), Handbook of Position Location: Theory, Practice and Advances, 2:nd Ed., February, 2019.
Theses
(T1) T. Smed and T. Wigren, "Simulering av frekvensdomänscrambler, som ej kräver synkronisering", M.Sc. Thesis, UPTEC 8540E, Department of Technology, Uppsala University, Uppsala, Sweden, June, 1985. (in Swedish)
(T2) T. Wigren, "Recursive identification based on the nonlinear Wiener model", Ph.D. thesis, Acta Universitatis Upsaliensis, Uppsala Dissertations from the Faculty of Science 31, Uppsala University, Uppsala, Sweden, December, 1990. Available: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-118290
Journal Papers
(J1) T. Wigren and A. Nehorai, "Asymptotic Cramér-Rao bounds for estimation of the parameters of damped sine waves in noise, IEEE Trans. Signal Processing, vol. 39, no. 4, pp. 1017-1020, 1991.
(J2) T. Wigren, "Recursive prediction error identification using the nonlinear Wiener model", Automatica, vol. 29, no. 4, pp. 1011-1025, 1993.
(J3) T. Wigren, "Convergence analysis of recursive identification algorithms based on the nonlinear Wiener model", IEEE Trans. Automat. Contr., vol. AC-39, no. 11, pp. 2191-2206, 1994.
(J4) T. Wigren, "Approximate gradients, convergence and positive realness in recursive identification of a class of nonlinear systems", Int. J. Adaptive Contr. Signal Processing, vol. 9, no. 4, pp. 325-354, 1995.
(J5) T. Wigren and A. Eriksson, "Accuracy aspects of DOA and angular velocity estimation in sensor array processing", IEEE Signal Processing Lett., vol. SPL-2, no. 4, pp. 60-62, 1995.
(J6) P. Händel, A. Eriksson and T. Wigren, "Performance analysis of a correlation based single tone frequency estimator", Signal Processing, vol. 44, no. 2, pp. 223-231, 1995.
(J7) U. Lindgren, T. Wigren and H. Broman, "On local convergence of a class of blind separation algorithms", IEEE Trans. Signal Processing, vol. 43, no. 12, pp. 3054-3058, 1995.
(J8) T. Wigren, "Circle criteria in recursive identification", IEEE Trans. Automat. Contr. , vol. 42, no. 7, pp. 975-979, 1997.
(J9) T. Wigren, "ODE analysis and redesign in blind adaptation", IEEE Trans. Automat. Contr. , vol. 42, no. 12, pp. 1742-1747, 1997.
(J10) T. Wigren, "Avoiding ill-convergence of finite dimensional blind adaptation schemes excited by discrete symbol sequences", Signal Processing, vol. 62, no. 2, pp. 121-162, 1997.
(J11) T. Wigren, "Fast converging and low complexity adaptive filtering using an averaged Kalman filter", IEEE Trans. Signal Processing , vol. 46, no. 2, pp. 515-518, 1998. [EC]
(J12) T. Wigren, "Output error convergence of adaptive filters with compensation for output nonlinearities", IEEE Trans. Automat. Contr., vol. 43, no. 7, pp. 975-978, 1998.
(J13)T. Wigren, "Adaptive filtering using quantized output measurements", IEEE Trans. Signal Processing , vol. 46, no. 12, pp. 3423-3426, 1998.
(J14) C. Carlemalm, S. Halvarsson, T. Wigren and B. Wahlberg, "Algorithms for time delay estimation using a low complexity exhaustive search", IEEE Trans. Automat. Contr. , vol. 44, no. 5, pp. 1031-1037, 1999.
(J15) T. Wigren and A. E Nordsjö, "Compensation of the RLS algorithm for output nonlinearities", IEEE Trans. Automat. Contr. , vol. 44, no. 10, pp. 1913-1918, 1999.
(J16) E. Sviestins and T. Wigren, "Optimal recursive state estimation with quantized measurements", IEEE Trans. Automat. Contr. , vol. 45, no. 4, pp. 762-767, 2000. [ATC]
(J17) T. Wigren, S. Halvarsson and B. Wahlberg, "Analysis of a low complexity change detection scheme", Int. J. Adaptive Contr. Signal Processing , vol. 14, pp. 481-503, 2000.
(J18) E. Sviestins and T. Wigren, "Nonlinear techniques for Mode C climb/descent rate estimation in ATC systems", IEEE Trans. Contr. Sys. Tech. , vol. 9, pp. 163-174, 2001. [ATC]
(J19) A. E. Nordsjö and T. Wigren, "On estimation of model errors caused by nonlinear undermodeling in system identification", Int. J. Contr. , vol. 75, no. 14, pp. 1100-1113, 2002.
(J20) E. Abd-Elrady, T. Söderström and T. Wigren, "Periodic signal analysis based on Lienard's equation", IEEE Trans. Automat. Contr., vol. 49, no. 10, pp. 1773-1778, 2004.
(J21) T. Söderström, T. Wigren and E. Abd-Elrady, "Periodic signal analysis by maximum likelihood modeling of orbits of nonlinear ODEs", Automatica , vol. 41, no. 5, pp. 793-805, 2005.
(J22) T. Wigren, "Discussion on: Subspace identification of multivariable Hammerstein and Wiener models", European J. Contr., vol. 11, no. 2, pp. 148-149, 2005. Invited paper.
(J23) T. Wigren and T. Söderström, "A second order ODE is sufficient for modeling of many periodic signals", Int. J. Contr. , vol. 78, no. 13, pp. 982-996, Sep., 2005.
(J24) T. Wigren, "Recursive prediction error identification and scaling of nonlinear state space models using a restricted black box parameterization", Automatica, vol. 42, no. 1, pp. 159-168, 2006.
(J25) T. Wigren, "Adaptive enhanced cell ID fingerprinting localization by clustering of precise position measurements", IEEE Trans. Vehicular Tech., vol. 56, no. 5, pp. 3199-3209, September, 2007. [SMLC,ESMLC]
(J26) L. Brus, T. Wigren and B. Carlsson, "Initialization of a nonlinear identification algorithm applied to laboratory plant data", IEEE Trans. Contr. Sys. Tech., vol. 16, no. 4, pp. 708-716, 2008.
(J27) M. Evestedt, A. Medvedev and T. Wigren, "Windup properties of recursive parameter estimation algorithms in acoustic echo cancellation", Contr. Eng. Practice, vol. 16, pp. 1372-1378, 2008.
(J28) T. Wigren, "Soft uplink load estimation in WCDMA", IEEE Trans. Vehicular Tech., vol. 58, no. 2, pp. 760-772, February, 2009.
(J29) T. Wigren and T. Palenius, "Optimized search window alignment for A-GPS", IEEE Trans. Vehicular Tech., vol. 58, no. 8, pp. 4670-4675, October, 2009.
(J30) T. Wigren, "Recursive noise floor estimation in WCDMA", IEEE Trans. Vehicular Tech., vol. 59, no. 5, pp. 2615-2620, 2010. [NB]
(J31) L. Brus, T. Wigren and D. Zambrano, "Feedforward model predictive control of a non-linear solar collector plant with varying delays", IET J. Contr. Theory and Applications, vol. 4, no. 8, pp. 1421-1435, 2010.
(J32) J. Wennervirta and T. Wigren, "RTT positioning field performance", IEEE Trans. Vehicular Tech., vol. 59, no. 7, pp. 3656-3661, 2010. [RNC,SAS,SMLC,ESMLC]
(J33) T. Wigren, "A polygon to ellipse transformation enabling fingerprinting and emergency localization in GSM", IEEE Trans. Vehicular Tech., vol. 60, no. 4, pp. 1971-1976, 2011. [SMLC]
(J34) B. I. Godoy, G. C. Goodwin, J. C. Aguero, D. Marelli and T. Wigren, "Identification of FIR systems having quantized output data using a scenario-based EM algorithm", Automatica, vol. 47, no. 9, pp. 1905-1915, 2011.
(J35) M. M. Silva, T. Wigren and T. Mendonca, "Nonlinear identification of a minimal Neuromuscular Blockade model in anaesthesia", IEEE Trans. Contr. Sys. Tech., vol. 20, no.1, pp. 181-188, 2012.
(J36) T. Wigren, "Fingerprinting localization using RTT and TA", IET Comm., vol. 6, no. 4, pp. 419-427, 2012. [SMLC,ESMLC]
(J37) T. Wigren, "WCDMA uplink load estimation with generalized rake receivers", IEEE Trans. Vehicular Tech., vol. 61, no. 5, pp. 2394-2400, 2012.
(J38) D. E. Quevedo and T. Wigren, "Design of embedded filters for inner-loop power control in CDMA communication systems", Asian J. Contr., vol. 14, no.4, pp. 891-900, 2012.
(J39) A. Kangas and T. Wigren, "Angle of arrival localization in LTE using MIMO pre-coder index feedback", IEEE Comm. Lett., vol. 17, no. 8, pp. 1584-1587, 2013.
(J40) O. Rosen, A. Medvedev and T. Wigren, "Parallelization of the Kalman filter for banded systems on multicore computational platforms", Contr. Eng. Practice, vol. 21, no. 9, pp. 1188-1194, 2013.
(J41) K. Lau, G. C. Goodwin, E. G.- Lundin, T. Wigren and S. Craig, "Uplink load based scheduling for CDMA Systems", IEEE Comm. Lett., vol. 17, no. 11, pp. 2136-2139, 2013.
(J42) M. M. Silva, J. M. Lemos, A. Coito, B. A. Costa, T. Wigren and T. Mendonca, "Local identifiability and sensitivity analysis of neuromuscular blockade and depth of hypnosis models", Computer Methods and Programs in Biomedicine, vol. 113, pp.23-36, 2014.
(J43) M. M. Silva, T. Wigren and T. Mendonca, "A reduced MIMO Wiener model for recursive identification of the depth of anesthesia", Int. J. Adaptive Contr. Signal Processing, vol. 28, no. 12, pp. 1357-1371, 2014.
(J44) M. M. Silva, L Paz, T. Wigren and T. Mendonca, "Performance of an adaptive controller for the neuromuscular blockade based on inversion of a Wiener model", Asian J. Contr., vol. 17, no. 4, pp. 1136-1147, July, 2015. Invited paper. DOI: 10.1002/asjc.981.
(J45) M. M. Silva, A. Medvedev, T. Wigren and T. Mendonca, "Modeling the effect of intravenous anesthetics: a path towards individualization", IEEE Design and Test of Computers, vol. 32, no. 5, pp. 17-26, 2015. DOI: 10.1109/MDAT.2015.2452904.
(J46) T. Wigren, "Wireless interference power estimation for inter-cell interference coordination", IET Comm., vol. 9, no. 12, pp. 1539 - 1546, 2015. DOI: 10.1049/iet-com.2014.0831.
(J47) T. Wigren, "Model order and identifiability of non-linear biological systems in stable oscillation", ACM/IEEE Trans. Computational Biology and Bioinformatics, vol. 12, no. 6, pp. 1479-1484, December, 2015. DOI: 10.1109/TCBB.2015.2404799.
(J48) T. Wigren, "Wireless feedback and feedforward data flow control subject to rate saturation and uncertain delay", IET Control Theory & Applications, vol. 10, no. 3, pp. 346-353, 2016. DOI: 10.1049/iet-cta.2015.0580.
(J49) T. Wigren, "Robust L_2 stable networked control of wireless packet queues in delayed internet connections", IEEE Trans. Contr. Sys. Tech., vol. 24, no. 2, pp. 502-513, 2016. DOI: 10.1109/TCST.2015.2455933. [NB,RNC]
(J50) S. Tayamon and T. Wigren, "Control of selective catalytic reduction systems using feedback linearization", Asian J. Contr., vol. 18, no. 3, pp. 802-816, 2016. DOI: 10.1002/asjc.1164.
(J51) T. Wigren, "Low frequency sensitivity function constraints for nonlinear L_2-stable networked control", Asian J. Contr., vol. 18, no. 4, pp. 1200-1218, 2016. DOI: 10.1002/asjc.1241.
(J52) P. Mattsson and T. Wigren, "Convergence analysis for recursive Hammerstein identification", Automatica, vol. 71, pp. 179-186, 2016.
(J53) K.Lau, G. C. Goodwin, T. Wigren and L. Brus, "Improving the performance of cellular uplinks via power overbooking", IET Comm., vol. 11, no. 9, pp. 1512-1518, 2017. DOI: 10.1049/iet-com.2016.1068.
(J54) T. Wigren, "Loop-shaping feedback and feedforward control for networked systems with saturation and delay", Asian J. Contr., vol. 19, no. 4, pp. 1329-1349, 2017. DOI: 10.1002/asjc.1442.
(J55) T. Wigren and R. Karaki, "Globally stable wireless data flow control", IEEE Trans. Contr. Network Systems, vol. 5, no. 1, pp. 469-478, 2018. DOI: 10.1109/TCNS.2016.2619906. [GNB]
(J56) T. Wigren, K. Lau, R. Delgado and R. H. Middleton, "Delay skew packet flow control in 5G wireless systems with dual connectivity", IEEE Trans. Vehicular Tech., vol. 67, no. 6, pp. 5357-5371, 2018.
(J57) T. Wigren, "A disturbance rejection and data rate trade-off in networked data flow control", European J. Contr., vol. 47, pp. 1-10, May, 2019.
(J58) J. Nygren, T. Wigren and K. Pelckmans, "Frequency conditions for stable networked controllers with time delay", Int. J. Contr., vol. 92, no. 4, pp. 886-895, 2019.
(J59) R. H. Middleton, T. Wigren, L. Boström, R. A. Delgado, K. Lau, R. Karlsson, L. Brus and E. Corbett, "Feedback control applications in new radio - exploring delay control and alignment", IEEE Vehicular Technology Magazine, vol. 14, no. 2, pp. 70-77, June, 2019. DOI: 10.1109/MVT.2019.2892495. Available: https://ieeexplore.ieee.org/document/8664474.
(J60) R. A. Delgado, K. Lau, R. H. Middleton and T. Wigren, "Networked delay control for 5G wireless machine type communications using multi-connectivity", IEEE Trans. Contr. Sys. Tech., vol. 27, no. 4, pp. 1510-1525, 2019.
(J61) T. Chistiakova, T. Wigren and B. Carlsson, "Combined L_2-stable feedback and feedforward aeration control in a wastewater treatment plant", IEEE Trans. Contr. Sys. Tech., vol. 28, no. 3, pp. 1017-1024, 2020. DOI: 10.1109/TCST.2019.2891410.
(J62) C. Törnevik, T. Wigren, S. Guo and K. Huisman, "Time averaged power control of a 4G or a 5G radio base station for RF EMF compliance", IEEE Access, vol. 8, pp. 211937 - 211950, Nov. 19, 2020. DOI 10.1109/ACCESS.2020.3039365. Available: https://ieeexplore.ieee.org/document/9264244 [ENB,GNB]
(J63) T. Wigren, K. Lau, R. Delgado and R. H. Middleton, "Globally stable delay alignment for feedback control over NR multi-point connections", IEEE Trans. Contr. Network Systems (CONES), vol. 7, no. 4, pp. 1633 - 1642, December, 2020. DOI 10.1109/TCNS.2020.2989786. Available: https://ieeexplore.ieee.org/document/9076793
(J64) T. Wigren, "Recursively filtered MIMO transmission with quadratic complexity", IEEE Wireless Comm. Letters, vol. 10, no. 5, pp. 929-933, 2021. DOI 10.1109/LWC.2021.3050388
(J65) T. Wigren and C. Törnevik, "Coordinated average EIRP control of radio transmitters for EMF exclusion zone computation", IEEE Wireless Comm. Letters, vol. 10, no. 9, pp. 2075-2079, 2021. DOI 10.1109/LWC.2021.3092190.
(J66) T. Wigren and D. Yamalova, "Constrained optimal average power control for wireless transmission", IEEE Contr. Systems Letters, vol.6, pp. 1922-1927, 2022. DOI: 10.1109/LCSYS.2021.3133632 [GNB]
(J67) T. Wigren and S. Yasini, "Passive UAV tracking in wireless networks", IEEE Trans. Aerospace and Electronic Systems, vol. 58, no.5, pp. 4101-4118, 2022. DOI 10.1109/TAES.2022.3158640.
(J68) T. Wigren, "Recursive identification of a nonlinear state space model", Int. J. Adaptive Contr. Signal Processing, vol. 37, no. 2, pp. 447-473, 2023. Online: https://onlinelibrary.wiley.com/doi/full/10.1002/acs.3531
(J69) T. Wigren, "Robust networked L_2-stable wireless SINR control", Int. J. Robust and Nonlinear Contr., vol. 34, pp. 5833-5851, 2024. DOI 10.1002/rnc.7295.
(J70) J. Hu, D. Zachariah, T. Wigren and P. Stoica, "Adaptive input design for nonlinear system identification with operational constraints", submitted to Automatica, 2024.
Conference Contributions
(C1) T. B. Minde, T. Wigren, J. Ahlberg and H. Hermansson, "Techniques for low bit rate speech coding using long analysis frames", Proc. ICASSP, Minneapolis, Minnesota, U.S.A., pt. II, pp. 604-607, 1993. [DA]
(C2) B. Carlsson and T. Wigren, "On-line identification of the dissolved oxygen dynamics in an activated sludge process", Preprints 12th World Congress of IFAC, Sydney, Australia, vol. 7, pp. 421-426, 1993.
(C3) T. Wigren, A. Bergström, S. Harrysson, F. Jansson and H. Nilsson, "Improvements of background sound coding in linear predictive speech coders", Proc. ICASSP, Detroit, Michigan, U.S.A., pp. 25-28, 1995. [DA]
(C4) T. Wigren and H. Egnell, "Automatic target identification and multi-sensor data fusion in air defense command and control systems", Proc. Milinf 1996 , Swedish Defense Material Organization, Enköping, Sweden, June 1996.
(C5) A. E. Nordsjö, B. M. Ninness and T. Wigren, "Quantifying model errors caused by nonlinear undermodeling in linear system identification", Preprints 13th World Congress of IFAC, San Francisco, California, U.S.A., vol. 1, pp. 145--149, 1996.
(C6) T. Wigren and P. Händel, "Harmonic signal modeling using adaptive nonlinear function estimation", Proc. ICASSP, Atlanta, Georgia, U.S.A., pp. 2952-2955, 1996.
(C7) S. Halvarsson, T. Wigren and B. Wahlberg, "A test statistics for low complexity change detection in dynamic systems based on averaged filter models", Proc. ICASSP , Atlanta, Georgia, U.S.A., pp. 2845-2848, 1996.
(C8) T. Wigren, E. Sviestins and H. Egnell, "Operational multi-sensor tracking for air defense", Proc. First Australian Data Fusion Symposium , Adelaide, Australia, pp. 13-18, Nov. 21-22, 1996.
(C9) T. Wigren, "Noncooperative target type identification in multi-sensor tracking", Proc. IRCTR Colloquium on Surveillance Sensor Tracking , Delft Technical University, Delft, the Netherlands, pp. 1-12, June 26, 1997. Invited paper.
(C10) T. Wigren and B. Carlsson, "On the use of quantized lambda-sensor measurements in recursive identification of air-fuel mixing dynamics", Preprints of the IFAC Workshop on Intelligent Components for Vehicles , Seville, Spain, pp. 77-82, March 23-24, 1998.
(C11) A. Lingvall, M. Björkman and T. Wigren, "Color vision based road estimation for automotive safety systems", Proc. 7th World Congress on Intelligent Transportation Systems , Turin, Italy, Nov. 6-9, 2000.
(C12) T. Wigren, "Target type probability combining algorithms for multi-sensor tracking", Proc. Aerosense 2001, SPIE, Orlando, FL, vol 4380, pp. 46-62, April 16-20, 2001.
(C13) T. Wigren, E. Abd-Elrady and T. Söderström, "Harmonic signal analysis with Kalman filters using periodic orbits of nonlinear ODEs", Proc. ICASSP 2003, Hong Kong, China, vol. VI, pp. 669-672, 2003.
(C14) T. Wigren, "User choices and model validation in system identification using nonlinear Wiener models", Prep. 13:th IFAC Symposium on System Identification , Rotterdam, The Netherlands, pp. 863-868, August 27-29, 2003. Invited session paper.
(C15) T. Wigren, E. Abd-Elrady and T. Söderström, "Least squares harmonic signal analysis using periodic orbits of ODEs", Prep. 13:th IFAC Symposium on System Identification , Rotterdam, The Netherlands, pp.1584-1589, August 27-29, 2003.
(C16) A. Kangas and T. Wigren, "Location coverage and sensitivity with A-GPS", Proc. URSI Int. Symposium on Electromagnetic Theory , Pisa, Italy, May 23-27, 2004. Invited paper.
(C17) E. Abd-Elrady and T. Söderström and T. Wigren, "Periodic signal analysis using orbits of nonlinear ODEs based on the Markov estimator", Proc. IFAC Workshops ALCOSP and PSYCO , Yokohama, Japan, pp. 367-372, Aug. 30 - Sep. 1, 2004.
(C18) M. Evestedt, A. Medvedev and T. Wigren, "Comparative study of three recursive parameter estimation algorithms with application to acoustic echo cancellation", Reglermöte 2004 , Gothenburg, Sweden, June, 2004.
(C19) T. Wigren, "Scaling of the sampling period in nonlinear system identification", Proc. IEEE ACC 2005, Portland, Oregon, U.S.A., pp. 5058-5065, June 8-10, 2005.
(C20) T. Wigren, "Recursive identification based on nonlinear state space models applied to drum-boiler dynamics with nonlinear output equations", Proc. IEEE ACC 2005 , Portland, Oregon, U.S.A., pp. 5066-5072, June 8-10, 2005.
(C21) M. Evestedt, A. Medvedev and T. Wigren, "Windup properties of recursive parameter estimation algorithms in acoustic echo cancellation", Prep. of the 16:th IFAC World Congress , Prague, Czech Republic, July 3-8, 2005.
(C22) L. Brus and T. Wigren, "Constrained ODE modeling and Kalman filtering for recursive identification of nonlinear systems", Proc. of the 14th IFAC Symposium on System Identification, SYSID 2006 , Newcastle, Australia, pp. 997-1002, March 29-31, 2006.
(C23) L. Brus, T. Wigren and B. Carlsson, "Kalman filtering for black-box identification of nonlinear ODE models", Reglermöte 2006, Stockholm, Sweden, May 30-31, 2006.
(C24) T. Wigren and L. Brus, "Criteria and time horizon in feedforward MPC for non-linear systems with time delays", Proc. 7th IFAC Symposium on Nonlinear Control Systems, NOLCOS 2007 , Pretoria, South Africa, pp. 782-787, August 22-24, 2007. DOI 10.3182/20070822-3-ZA-2920.00129.
(C25) T. Wigren and L. Brus, "Reduction of amplitude dependent gain variations in control of non-linear Wiener type systems", Proc. 7th IFAC Symposium on Nonlinear Control Systems, NOLCOS 2007, Pretoria, South Africa, pp. 336-341, August 22-24, 2007. DOI 10.3182/20070822-3-ZA-2920.00056.
(C26) T. Wigren and P. Hellqvist, "Estimation of uplink WCDMA load in a single RBS", Proc. IEEE VTC2007-Fall, Baltimore, MD, U.S.A., October 1-3, 2007. [NB]
(C27) J. -C. Aguero, B. I. Godoy, G. C. Goodwin and T. Wigren, "Scenario-based EM identification for FIR systems having quantized output data", Proc. of the 15th IFAC Symposium on System Identification, SYSID 2009, Saint-Malo, France, pp. 66-71, July 6-8, 2009.
(C28) T. Wigren and J. Wennervirta, "RTT positioning in WCDMA", Proc. of the 5th International Conference on Wireless and Mobile Communications, ICWMC 2009, Cannes/La Bocca, France, pp. 303-308, August 23-29, 2009. [RNC,SAS,SMLC,ESMLC]
(C29) H. Alonso, T. Mendonca, J. M. Lemos and T. Wigren, "A simple model for the identification of drug effects", Proc. of the 6:th International Symposium on Intelligent Signal Processing, WISP 2009, pp. 269-273, Budapest, Hungary, August 26-28, 2009.
(C30) L. Shi and T. Wigren, "AECID fingerprinting positioning performance", Proc. Globecomm 2009, Honolulu, U.S.A, pp. 2767-2772, Nov. 30 - Dec. 4, 2009. [SMLC,ESMLC]
(C31) J. C. Aguero, G. C. Goodwin, K. Lau, M. Wang, E. I. Silva and T. Wigren, "Three-degree of freedom adaptive power control for CDMA cellular systems", Proc. Globecomm 2009, pp. 2767-2772, Honolulu, Nov. 30 - Dec. 4, U.S.A, 2009.
(C32) T. Wigren, M. Anderson and A. Kangas, "Emergency call delivery standards impair cellular positioning accuracy", Proc. ICC 2010, Cape Town, South Africa, May 23-27, 2010.
(C33) J. Almeida, M. M. Silva, T. Wigren and T. Mendonca, "Contributions to the initialization of online identification algorithms for anaesthesia: the neuromuscular blockade case study", Proc. 18:th Mediterranean Conference on Control and Automation, Marrakesh, Morocco, pp. 1341 - 1346, June 23-25, 2010.
(C34) M. M. Silva, T. Mendonca and T. Wigren, "Online nonlinear identification of the effect of drugs in anaesthesia using a minimal parameterization and BIS measurements", Proc. ACC 2010, Baltimore, MD, U.S.A., pp. 4379 - 4384, June 30-July 02, 2010.
(C35) S. Tayamon and T. Wigren, "Recursive prediction error identification and scaling of non-linear systems with midpoint integration", Proc. ACC 2010, Baltimore, MD, U.S.A., pp. 4510-4515, June 30-July 02, 2010.
(C36) M. M. Silva, J. Almeida, T. Wigren and T. Mendonca, "Merging PK/PD information in a minimally parameterized model of the NeuroMuscular Blockade", Proc. 32:nd Int. Conference of the IEEE EMBS, Buenos Aires, Argentine, pp. 4602-4605, August 31-September 4, 2010.
(C37) D. Zambrano, S. Tayamon, B. Carlsson and T. Wigren, "Identification of a discrete-time nonlinear Hammerstein-Wiener model for a selective catalytic reduction system", Proc. ACC 2011, San Fransisco, U.S.A., pp. 78-83, June 29-July 1, 2011.
(C38) S. Tayamon, D. Zambrano, T. Wigren and B. Carlsson, "Nonlinear black box identification of a selective catalytic reduction system", Proc. 18:th IFAC world congress, Milan, Italy, pp. 11845--11850, August 28-September 2, 2011.
(C39) K. Lau, G. C. Goodwin, M. Cea and T. Wigren, "Linear and nonlinear decoupling for inner loop power control in 3G mobile communications", Proc. 18:th IFAC world congress, Milan, Italy, pp. 9194-9199, August 28-September 2, 2011.
(C40) T. Wigren, I. Siomina and M. Andersson, "Estimation of prior positioning method performance in LTE", Proc. IEEE PIMRC, Toronto, Canada, pp. 1284-1288, September 11-14, 2011.
(C41) M. M. Silva, T. Wigren, T. Mendonca, E. W. Jensen and P. Gambus, "Sedation-analgesia with Propofol and Remifentanil: new model for individualized BIS prediction", Anesthesiology 2011, Chicago, Il, U.S.A., October 15-19, 2011.
(C42) M. M. Silva, T. Mendonca and T. Wigren, "Nonlinear adaptive control of the neuromuscular blockade level in anaesthesia", Proc. IEEE CDC, Orlando, FL, U.S.A, pp. 41-46, December 12-15, 2011.
(C43) T. Wigren, "Clustering and polygon merging algorithms for fingerprinting positioning in LTE", Proc. 5th International conference on signal processing and communication systems, ICSPCS 2011, Honolulu, HI, December 12-14, 2011.
(C44) T. Wigren, "Low complexity Kalman filtering for inter-cell interference and power based load estimation in the WCDMA uplink", Proc. 5th International conference on signal processing and communication systems, ICSPCS 2011, Honolulu, HI, December 12-14, 2011.
(C45) M. M. Silva and T. Wigren, "Adaptive control of propofol-induced hypnosis in anesthesia using a minimally parameterized Wiener model", Proc. Reglermöte 2012, paper 167, Uppsala, Sweden, June 13-14, 2012.
(C46) M. M. Silva, R. Rabico, T. Mendonca, T. Wigren, "Control of rocuronium-induced neuromuscular blockade via online identification of a two-parameters Wiener model", Proc. SYSID 2012, Brussels, Belgium, pp. 571-576, July 11-13, 2012. Invited paper.
(C47) S. Tayamon and T. Wigren, "Convergence analysis of a recursive prediction error method", Proc. SYSID 2012, Brussels, Belgium, pp. 1496-1501, July 11-13, 2012.
(C48) M. G. Cea, G. C. Goodwin and T. Wigren, "Model Predictive Zooming Power Control in Future Cellular Systems Under Coarse Quantization", Proc. IEEE VTC2012 Fall, Quebec City, Canada, September 3-6, 2012.
(C49) T. Wigren, "LTE fingerprinting localization with altitude", Proc. IEEE VTC2012 Fall, Quebec City, Canada, September 3-6, 2012.
(C50) T. Wigren, A. Kangas, Y. Jading, I. Siomina and C. Tidestav, "Enhanced WCDMA fingerprinting localization using OTDOA positioning measurements from LTE", Proc. IEEE VTC2012 Fall, Quebec City, Canada, September 3-6, 2012.
(C51) G. Xinyu, Z. Zhang, S. Grant, T. Wigren, N. Johansson, A. Kangas, "Load control for multi-stage interference cancellation", Proc. PIMRC 2012, Sydney, Australia, pp. 355-360, September 9-12, 2012.
(C52) S. Tayamon, T. Wigren and J. Schoukens, "Convergence analysis and experiments using an RPEM based on nonlinear ODEs and midpoint integration", Proc. IEEE CDC 2012, Maui, HI, pp. 2858-2865, December 10-13, 2012.
(C53) M. M. Silva, T. Wigren and T. Mendonca, "Exactly linearizing adaptive control of propofol and remifentanil using a minimally parameterized depth of anesthesia Wiener model", Proc. IEEE CDC 2012, Maui, HI, pp. 368-373, December 10-13, 2012.
(C54) M. M. Silva, T. Wigren, A. M. Medvedev and T. Mendonca, "Quantification of the multiplicative uncertainty in the linearized minimally parameterized parsimonious Wiener model for the neuromuscular blockade in closed-loop anesthesia", Proc. 21th Mediterrean Conference on Control and Automation, Crete, Greece, June 25-28, 2013.
(C55) T. Wigren and J. Schoukens, "Three free data sets for development and benchmarking in nonlinear system identification", Proc. ECC 2013, Zurich, Switzerland, pp. 2933-2938, July 17-19, 2013.
(C56) P. Mattsson and T. Wigren, "Recursive identification of Hammerstein models ", Proc. American Control Conference ACC 2014, Portland, OR, U.S.A., pp. 2498-2503, June 4-6, 2014.
(C57) S. Tayamon, T. Wigren and B. Carlsson "NOx control for SCR systems using feedback linearisation", ERNSI 2014, Ostend, Belgium, September 21-24, 2014.
(C58) D. Sandberg and T. Wigren, "Multi-rate uplink channel prediction and enhanced link adaptation for VoLTE", Proc. VTC 2015 Fall, Boston, Ma, Sep. 6-9, 2015.
(C59) T. Wigren, D. Colombi, B. Thors and J.-E. Berg, "Implications of RF EMF exposure limitations on 5G data rates above 6 GHz", Proc. VTC 2015 Fall, Boston, Ma, Sep. 6-9, 2015.
(C60) M. Schoukens, P. Mattsson, T. Wigren and J. P. Noel, "Cascaded tanks benchmark combining soft and hard nonlinearities", ERNSI 2015, Varberg, Sweden, September 20-23, 2015.
(C61) T. Wigren, "Low-frequency limitations in saturated and delayed networked control", Proc. IEEE CCA 2015, Sydney, Australia, pp. 564-571, Sep. 21-23, 2015. DOI: 10.1109/CCA.2015.7320690.
(C62) T. Wigren, "Nonlinear identification of neuron models", Proc. IEEE CCA, Sydney, Australia, pp. 1340-1346, Sep. 21-23, 2015. DOI: 10.1109/CCA.2015.7320798.
(C63) J. Nordh, T. Wigren, T. Schön and B. Bernhardsson, "Particle filtering based identification for autonomous nonlinear ODE models", Proc. SYSID 2015, Beijing, PRC, pp. 415-420, October 19-21, 2015.
(C64) T. Wigren and P. Lötstedt, "Nonlinear identification of biological clock dynamics", Proc. IEEE CDC 2015, Osaka, Japan, pp. 602-608, December 15-18, 2015.
(C65) T. Chistiakova, B. Carlsson and T. Wigren, "Nonlinear stability analysis of an ammonium feedback control system", Abstract (unpublished), Reglermöte 2016, Gothenburgh, Sweden, June 8-9, 2016.
(C66) R. H. Middleton, T. Wigren, K. Lau and R. Delgado, "Data flow delay equalization for feedback control applications using 5G wireless dual connectivity", Proc. VTC 2017 Spring, Sydney, Australia, June 4-7, 2017.
(C67) T. Chistiakova, B. Carlsson and T. Wigren, "Non-linear modelling of the dissolved oxygen to ammonium dynamics in a nitrifying activated sludge process", Proc. ICA 2017, Quebec City, Quebec, Canada, pp. 85-93, June 11-14, 2017.
(C68) T. Chistiakova, P. Mattsson, B. Carlsson and T. Wigren, "Nonlinear system identification of the dissolved oxygen to effluent ammonia dynamics in an activated sludge process", Proc. IFAC 2017 World Congress, Tolouse, France, pp. 3978-3983, July 9-15, 2017.
(C69) R. A. Delgado, K. Lau, R. Middleton, R. S. Karlsson, T. Wigren and Y. Sung, "Fast convergence outer loop link adaptation with infrequent updates in steady state", IEEE VTC-Fall 17, Toronto, Canada, September 24-27, 2017.
(C70) K. Lau, T. Wigren, R. Delgado and R. H. Middleton, "Disturbance rejection properties for a 5G networked data flow delay controller", IEEE CDC 2017, Melbourne, Australia, pp. 1681-1687, Dec. 12-15, 2017.
(C71) T. Wigren, "Networked and delayed recursive identification of nonlinear systems", IEEE CDC 2017, Melbourne, Australia, pp. 5851-5858, Dec. 12-15, 2017.
(C72) A. Medvedev, F. Olsson and T. Wigren, "Tremor quantification through data-driven nonlinear system modeling", IEEE CDC 2017, Melbourne, Australia, pp. 5943-5948, Dec. 12-15, 2017.
(C73) T. Wigren, "Wireless hybrid positioning based on surface modeling with polygon support", IEEE VTC-Spring, Porto, Portugal, June 3-6, 2018.
(C74) S. Yasini and T. Wigren, "Counterexamples to parametric convergence in recursive networked identification", ACC 2018, Milwaukee, USA, pp. 258-264, June 27-29, 2018.
(C75) R. A. Delgado, T. Wigren, K. Lau and R. H. Middleton, "Stability properties of a MIMO data flow controller", ACC 2018, Milwaukee, USA, pp. 2638-2643, June 27-29, 2018.
(C76) T. Chistiakova, T. Wigren and B. Carlsson, "Input-Output Stability Based Controller Design for a Nonlinear Wastewater Treatment Process", ACC 2018, Milwaukee, USA, pp. 2964-2971, June 27-29, 2018.
(C77) S. Yasini and T. Wigren, "Convergence in networked recursive identification with output quantization", SYSID 2018, Stockholm, Sweden, pp. 915-920, July 9-11, 2018.
(C78) K. Lau, T. Wigren, R. H. Middleton and R. Delgado, "Delay alignment control for 5G multi connectivity", Proc. IEEE CDC, Miami, FL, USA, pp. 7064-7070, December 17-19, 2018.
(C79) R. Delgado, T. Wigren, K. Lau, R. Middleton and I. Siomina, "Statistical beam information for mmW positioning", Proc. VTC2020-Spring, Antwerp, Belgium, May 25-28, 2020.
(C80) T. Wigren, Y. Sung, R. A. Delgado, K. Lau and R. H. Middleton, "Jitter suppression for very low latency feedback control over NR", Proc. VTC2020-Spring, Antwerp, Belgium, May 25-28, 2020.
(C81) T. Wigren, "Stable logarithmic control of a disturbance", Reglermöte 2022, Luleå, Sweden, June 7-9, 2022. [eNB,gNB]
(C82) R. Zhang, P. Mattsson and T. Wigren, "State observation and feedback in deep reinforcement learning", Reglermöte 2022, Luleå, Sweden, June 7-9, 2022.
(C83) R. Zhang, P. Mattsson and T. Wigren, "Robust nonlinear set-point control with reinforcement learning", Proc. ACC, San Diego, USA, pp.84-91, May 31-June 2, 2023.
(C84) T. Wigren and A. Teixeira, "On-line identification of delay attacks in networked servo control", Proc. IFAC World Congress, Yokohama, Japan, pp. 1041-1047, July 9-14, 2023.
(C85) R. Zhang, P. Mattsson and T. Wigren, "Aiding reinforcement learning for set point control", Proc. IFAC World Congress, Yokohama, Japan, pp. 2748-2754, July 9-14, 2023.
(C86) R. Zhang, P. Mattsson and T. Wigren, "Observer-feedback-feedforward structures in reinforcement learning", Proc. IFAC World Congress, Yokohama, Japan, pp. 6807-6912, July 9-14, 2023.
(C87) T. Wigren and A. Teixeira, "Feedback path delay attacks and detection", Proc. IEEE CDC, pp. 3864-3871, Singapore, December 13-15, 2023.
(C88) T. Wigren, "Logarithmic feedback control of passive interference", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 154-161, 2024. [eNB, gNB]
(C89) T. Wigren, "Convergence in delayed recursive identification of nonlinear systems", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 914-921, 2024.
(C90) S. Yasini and T. Wigren, "Round trip time based UAV state estimation", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 3776-3782, 2024.
(C91) T. Wigren and A. Teixeira, "Delay attack and detection in feedback linearized control systems", Proc. European Control Conference, Stockholm, Sweden, June 25-28, pp. 1569-1576, 2024.
(C92) D. Yamalova and T. Wigren, "Control signal switching in constrained control of averages", Proc. CDC, Milan, Italy, Dec. 16-19, to appear, 2024.
(C93) T. Wigren, R. Zhang and P. Mattsson,”Convergence in on-line learning of static and dynamic systems”, submitted to 7th Learning for Dynamics & Control Conference (L4DC), Ann Arbor, MI, USA, June 4-6, pp. xxxx-yyyy, 2025.
Technical Reports
(T1) T. Wigren and A. Nehorai, "Asymptotic Cramér-Rao bounds for estimation of damped sine waves in noise", Report No. 9005, Center for Systems Science, Department of Electrical Engineering, Yale University, New Haven, Connecticut, U.S.A., March, 1990.
(T2) B. Carlsson and T. Wigren, "On-line identification of the dissolved oxygen dynamics in an activated sludge process", UPTEC 92111R, Department of Technology, Uppsala University, Uppsala, Sweden, September, 1992.
(T3) T. Wigren and A. Eriksson, "A sensor array processing algorithm for joint DOA and angular velocity estimation", UPTEC 94062R, Department of Technology, Uppsala University, Uppsala, Sweden, June, 1994.
(T4) U. Lindgren, T. Wigren and H. Broman, "Analysis of a blind separation algorithm", CTH-TE-21, Department of Applied Electronics, Chalmers University of Technology, Gothenburg, Sweden, August, 1994.
(T5) T. Wigren, "Global parametric convergence of finite dimensional blind adaptation algorithms of constant modulus type", UPTEC 94101R, Department of Technology, Uppsala University, Uppsala, Sweden, December, 1994.
(T6) T. Wigren, "Globally convergent recursive identification with quantized output measurements", UPTEC 95035R, Department of Technology, Uppsala University, Uppsala, Sweden, March, 1995.
(T7) A. E. Nordsjö, B. M. Ninness and T. Wigren, "Quantifying model errors caused by nonlinear undermodeling in linear system identification", UPTEC 95089R , Department of Technology, Uppsala University, Uppsala, Sweden, June, 1995.
(T8) T. Wigren and B. Carlsson, "On-line estimation of air-fuel mixing dynamics using nonlinear lambda-sensor measurements", UPTEC 96121R , Department of Technology, Uppsala University, Uppsala, Sweden, August, 1996.
(T9) T. Wigren, S. Halvarsson and B. Wahlberg, "Analysis of a low complexity change detection scheme", UPTEC 97 037R , Department of Technology, Uppsala University, Uppsala, Sweden, March, 1997.
(T10) T. Wigren and T. Söderström, "Second order ODEs are sufficient for modeling of many periodic signals", Technical Reports from the department of Information Technology 025-2003, Uppsala University, Uppsala, Sweden, April, 2003.
(T11) E. Abd-Elrady, T. Söderström and T. Wigren, "Periodic signal modeling based on Lienard's equation", Technical Reports from the department of Information Technology 036-2003, Uppsala University, Uppsala, Sweden, August, 2003.
(T12) T. Söderström, T. Wigren and E. Abd-Elrady, "Maximum likelihood modeling of orbits of nonlinear ODEs", Technical Reports from the department of Information Technology 001-2004, Uppsala University, Uppsala, Sweden, January, 2004.
(T13) T. Wigren, "Recursive prediction error identification of nonlinear state space models", Technical Reports from the department of Information Technology 004-2004, Uppsala University, Uppsala, Sweden, January, 2004.
(T14) T. Wigren, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 1", Technical Reports from the department of Information Technology 2005-002, Uppsala University, Uppsala, Sweden, January, 2005.
(T15) T. Wigren, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 2", Technical Reports from the department of Information Technology 2005-022, Uppsala University, Uppsala, Sweden, August, 2005.
(T16) T. Wigren, "MATLAB software for recursive identification of Wiener systems - Revision 2 ", Technical Reports from the department of Information Technology 2007-010, Uppsala University, Uppsala, Sweden, March, 2007.
(T17) T. Wigren and L. Brus, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 3", Technical Reports from the department of Information Technology 2007-013, Uppsala University, Uppsala, Sweden, April, 2007.
(T18) T. Wigren, "MATLAB software for recursive identification of systems with output quantization - Revision 1 ", Technical Reports from the department of Information Technology 2007-015, Uppsala University, Uppsala, Sweden, April, 2007.
(T19) T. Wigren and L. Brus, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 4", Technical Reports from the department of Information Technology 2008-007, Uppsala University, Uppsala, Sweden, March, 2008.
(T20) M. M. Silva, T. Mendonca and T. Wigren, "Nonlinear identification of a minimal neuromuscular blockade model in anaesthesia", Technical Reports from the department of Information Technology 2009-023, Uppsala University, Uppsala, Sweden, September, 2009.
(T21) T. Wigren, L. Brus and S. Tayamon, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 5", Technical Reports from the department of Information Technology 2010-002, Uppsala University, Uppsala, Sweden, January, 2010.
(T22) M. M. Silva, T. Mendonca and T. Wigren, "Online nonlinear identification of the effect of drugs in anaesthesia using a minimal parameterization and BIS measurements", Technical Reports from the department of Information Technology 2010-008, Uppsala University, Uppsala, Sweden, March, 2010.
(T23) S. Tayamon and T. Wigren, "Recursive prediction error identification and scaling of non-linear systems with midpoint numerical integration", Technical Reports from the department of Information Technology 2010-011, Uppsala University, Uppsala, Sweden, March, 2010.
(T24) T. Wigren, "Input-output data sets for development and benchmarking in nonlinear identification", Technical Reports from the department of Information Technology 2010-020, Uppsala University, Uppsala, Sweden, August, 2010.
(T25) T. Wigren, L. Brus and S. Tayamon, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model - Revision 6", Technical Reports from the department of Information Technology 2010-022, Uppsala University, Uppsala, Sweden, September, 2010.
(T26) S. Tayamon and T. Wigren, "Recursive identification and scaling of non-linear systems using midpoint numerical integration", Technical Reports from the department of Information Technology 2010-025, Uppsala University, Uppsala, Sweden, October, 2010.
(T27) M. M. Silva, T. Wigren and T. Mendonca, "An adaptive controller for propofol in anesthesia under synergistic remifentanil disturbances", Technical Reports from the department of Information Technology 2012-011, Uppsala University, Uppsala, Sweden, May, 2012.
(T28) T. Wigren and J. Schoukens, "Data for benchmarking in nonlinear system identification", Technical Reports from the department of Information Technology 2013-006, Uppsala University, Uppsala, Sweden, March, 2013.
(T29) T. Wigren, "On a limitation in networked flow control", Technical Reports from the department of Information Technology 2014-009, Uppsala University, Uppsala, Sweden, March, 2014.
(T30) T. Wigren, "Software for recursive identification of second order autonomous systems", Technical Reports from the Department of Information Technology, 2014-014, Uppsala University, Uppsala, Sweden, April, 2014.
(T31) T. Wigren, "Identifiability and limit cycles", Technical Reports from the Department of Information Technology, 2014-016, Uppsala University, Uppsala, Sweden, May, 2014.
(T32) T. Wigren, "Constraints on nonlinear L_2 stable networked control", Technical Reports from the Department of Information Technology, 2015-013, Uppsala University, Uppsala, Sweden, May, 2015.
(T33) J. Nygren, T. Wigren and K. Pelckmans, "Delay-independent stability criteria for networked control systems", Technical Reports from the Department of Information Technology, 2015-018, Uppsala University, Uppsala, Sweden, June, 2015.
(T34) T. Wigren, "A tradeoff between data rate and regulation performance in networked data flow control", Technical Reports from the Department of Information Technology, 2016-003, Uppsala University, Uppsala, Sweden, January, 2016.
(T35) T. Wigren, "MATLAB Software for Nonlinear and Delayed Recursive Identification - Revision 1", Technical Reports from the Department of Information Technology, 2017-007, Uppsala University, Uppsala, Sweden, April, 2017.
(T36) S. Yasini and T. Wigren, "Parametric convergence analysis of an adaptive filtering algorithm with output quantization", Technical Reports from the Department of Information Technology, 2017-011, Uppsala University, Uppsala, Sweden, June, 2017.
(T37) R. A. Delgado, T. Wigren, K. Lau and R. H. Middleton, "Stability properties of a MIMO data flow controller", Technical Report, University of Newcastle, August, 2017. Available: http://hdl.handle.net/1959.13/1344681.
(T38) T. Wigren and M. Schoukens, "Coupled electric drives data set and reference models", Technical Reports from the Department of Information Technology, 2017-024, Uppsala University, Uppsala, Sweden, December, 2017.
(T39) T. Chistiakova, P. Mattsson, B. Carlsson and T. Wigren, "Nonlinear system identification of the dissolved oxygen to effluent ammonium dynamics in an activated sludge process", Technical Reports from the Department of Information Technology, 2018-011, Uppsala University, Uppsala, Sweden, August, 2018.
(T40) T. Wigren, "MATLAB software for recursive identification and scaling using a structured nonlinear black-box model – revision 7", Technical Reports from the Department of Information Technology, 2021-008, Uppsala University, Uppsala, Sweden, December, 2021.
(T41) T. Wigren, "MATLAB software for nonlinear and delayed recursive identification - revision 2", Technical Reports from the Department of Information Technology, 2022-002, Uppsala University, Uppsala, Sweden, January, 2022.
(T42) R. Zhang, P. Mattsson and T. Wigren, "A Robust Multi-Goal Exploration Aided Tracking Policy", Technical Reports from the Department of Information Technology, 2022-006, Uppsala University, Uppsala, Sweden, August, 2022.
Patents
(P1) T. Wigren, "Time variable spectral analysis based on interpolation for speech coding", US Patent 5 351 388, Sep. 24, 1994.
(P2) T. Wigren, A. Bergström and F. Jansson, "Rejected frame concealment", US Patent 5 572 622, Nov. 5, 1996.
(P3) T. Wigren, "Discriminating between stationary and non-stationary signals", US Patent 5 579 432, Nov. 26, 1996.
(P4) T. Wigren and A. Bergström, "Lost frame concealment", US Patent 5 596 678 , Jan. 21, 1997.
(P5) T. Wigren and A. Bergström, "Apparatus and a method for concealing transmission errors in a speech decoder", US Patent 5 598 506, Jan. 28, 1997.
(P6) T. Wigren, "Echo canceller having Kalman filter for optimal adaptation", US Patent 5 995 620, 1999.
(P7) T. Wigren, "Target type estimation in target tracking", European Patent EP0988561 A and US Patent 6 278 401 , March 29, 2000 (European), August 21, 2001 (US).
(P8) T. Wigren, "Position determination in wireless communication systems", US Patent 7 203 499, April 10, 2007.
(P9) T. Wigren and A. Lundqvist, "Altitude determination and distribution in cellular communication systems", US Patent 7 676 232 B2, March 9, 2010.
(P10) T. Wigren and M. Persson, "Method and arrangements relating to satellite based positioning", US Patent 7 692 582, April 6, 2010.
(P11) T. Wigren and T. Palenius, "Assisted satellite-based positioning", Chinese Patent CN1977183-B, December 1, 2010.
(P12) T. Wigren, G. Peters and T. Östman, "Methods and devices for uplink load estimation", US Patent 7 848 743, December 7, 2010.
(P13) T. Wigren, "Complexity reduction in power estimation", US Patent 7 912 461, March 22, 2011.
(P14) T. Wigren, "Load estimation using scheduled uplink power", US Patent 7 953 025, May 31, 2011.
(P15) T. Wigren, "Load estimation in receiver diversity telecommunication systems", US Patent 7 983 187, July 19, 2011.
(P16) T. Wigren, "Methods and arrangements for noise rise estimation", US Patent 8 005 433, August 23, 2011.
(P17) A. Kangas and T. Wigren, "Methods and arrangements relating to satellite-based positioning", US Patent 8 085 704, December 27, 2011.
(P18) T. Wigren, "Method and arrangement for enhanced cell identification and cell positioning", European Patent EP2119284(B1), March 7, 2012.
(P19) T. Wigren, "Method and arrangements for noise rise estimation", US patent 8 145 137, March 27, 2012.
(P20) T. Wigren and C. Tidestav, "Methods and arrangements for noise rise estimation",US Patent 8 170 492, May 1, 2012.
(P21) T. Wigren, "Extended positioning reporting", US Patent 8 170 582, May 1, 2012.
(P22) T. Wigren, "Path loss polygon positioning", US Patent 8 175 061, May 8, 2012.
(P23) T. Wigren, "Method and arrangememt for noise floor estimation", US Patent 8 175 537, May 8, 2012.
(P24) T. Wigren and A. Kangas, "Transformation of positioning reporting formats", US Patent 8 200 250, June 12, 2012.
(P25) T. Wigren, "Extended clustering for improved positioning", US Patent 8 208 942, June 26, 2012.
(P26) D. Gerstenberger, A. Kangas, D. Larsson and T. Wigren, "Angle of arrival downlink signaling", US Patent 8 233 920, July 31, 2012.
(P27) T. Wigren and B. Göransson, "OFDMA uplink interface impact recovery in LTE system", US Patent 8 280 394, October 2, 2012.
(P28) T. Wigren and A.Kangas, "Accuracy assessment in assisted GPS positioning", US Patent 8 289 206, October 16, 2012.
(P29) T. Wigren, "Method and arrangement for noise floor estimation", US Patent 8 301 083, October 30, 2012.
(P30) T. Wigren, "Method and arrangements for noise rise estimation", US Patent 8 306 091, November 6, 2012.
(P31) T. Wigren, "Adaptive enhanced cell identity positioning", US Patent 8 315 632, November 20, 2012.
(P32) T. Wigren, "Methods and arrangments for memory-efficient estimation of noise floor", US Patent 8 346 177, January 1, 2013.
(P33) T Wigren, "Methods and arrangements for fingerprinting positioning", European Patent EP2374021(B1), February 20, 2013.
(P34) T. Wigren, R. Baldemair, M. Kazmi, M. Israelsson and D. Gerstenberger, "Radio fingerprint method in a positioning node for providing geographical region data", US Patent 8 385 226, February 26, 2013.
(P35) T. Wigren and B. Hellander, "Method and arrangement for improved positioning", US Patent 8 385 948, February 26, 2013.
(P36) T. Wigren, Y. Jading and T. Tidestav, "LTE fingerprinting positioning references for other cellular systems", US Patent 8 401 570, March 19, 2013.
(P37) A. Kangas, B. Göransson and T. Wigren, "Positioning in telecommunication systems", US Patent 8 406 787, March 26, 2013.
(P38) T. Wigren and A. Kangas, "Method and arrangement for real-time difference determination for mobile terminal positioning", US Patent 8 489 098, July 16, 2013.
(P39) T. Wigren, J. Bolin and P. Willars, "Measurement systems and methods for fingerprinting positioning", European Patent EP2243037(B1), July 17, 2013.
(P40) T. Wigren, "Adaptive polygon computation in adaptive enhanced cell identity positioning", US Patent 8 494 550, July 23, 2013.
(P41) T. Wigren, "Method and arrangement for high precision position measurements at indoor locations", US Patent 8 504 058, August 6, 2013.
(P42) M. Ringström and T. Wigren, "Load scheduling in wideband code division multiple access", US Patent 8 565 094, October 22, 2013.
(P43) T. Wigren, D. Gerstenberger, S. Parkvall, A. Kangas, B. Göransson and J. Karlsson, "Scheduling for uplink and downlink time of arrival estimation", European Patent EP19008317(B1), November 13, 2013.
(P44) P. Willars, J. Bolin and T. Wigren, "Methods and systems for obscuring network topologies", US Patent 8 600 349, December 3, 2013.
(P45) T. Wigren, "Load estimation in interference whitening systems", US Patent 8 605 842, December 10, 2013.
(P46) T. Wigren, "Determining position of wireless terminal in telecommunications network", US Patent 8 654 010, February 18, 2014.
(P47) T. Wigren, "Method and arrangement for noise floor estimation", US Patent 8 665 854, March 4, 2014.
(P48) T. Wigren, "Load estimation in wireless communication", US Patent 8 665 937, March 4, 2014.
(P49) T. Wigren and L. Shi, "A method of improved positioning", US Patent 8 666 430, March 4, 2014.
(P50) T. Wigren, "Methods and arrangements for cell stability in a cellular communication system", US Patent 8 670 344, March 11, 2014.
(P51) T. Wigren and A. Kangas, "Load estimation in frequency domain pre-equalization systems", US Patent 8 670 478, March 11, 2014.
(P52) J. Bolin and T. Wigren, "Methods and systems for cell re-planning to obscure newtwork topologies", US Patent 8 676 217, March 18, 2014.
(P53) G. C. Goodwin, D. Quevedo and T. Wigren, "Wireless communication power control", US Patent 8 712 463, April 29, 2014.
(P54) T. Wigren and I. Siomina, "Method and arrangement for load management in heterogenous networks with interference suppression capable receivers", US Patent 8 717 924, May 6, 2014.
(P55) T. Wigren, "Method and arrangement for improved positioning", European Patent EP 2 488 886 (B1), May 7, 2014.
(P56) T. Wigren, I. Siomina and A. Kangas, "Enhanced angle-of-arrival positioning", US Patent 8 731 579, May 20, 2011.
(P57) T. Wigren and I. Siomina, "Method and arrangement for positioning a wireless device", US Patent 8 743 725, June 3, 2014.
(P58) T. Wigren and P. Karlsson, "Scheduling different types of receivers in a radio base station", US Patent 8 743 839, June 3, 2014.
(P59) R. Baldemair, M. Israelsson, D. Gerstenberger, M. Kazmi, T. Wigren, "Method for providing geographical position related information in a wireless network", US Patent 8 744 481, June 3, 2014.
(P60) A. Kangas and T. Wigren, "Method and apparatus for position determination in a cellular communications system", US Patent 8 755 816, June 17, 2014.
(P61) I. Siomina and T. Wigren, "Signaling support enabling QoS discrimination for positioning, location and location-based services in LTE", US Patent 8 768 289, July 1, 2014.
(P62) T. Wigren, "Method and device for noise floor estimation", US Patent 8 787 858, July 22, 2014.
(P63) I. Siomina and T. Wigren, "Language dependent positioning and signalling", US Patent 8 804 574, August 12, 2014.
(P64) T. Wigren, "Method for noise floor and interference estimation", European Patent EP2171890 (B1), August 28, 2014.
(P65) J. Bolin, T. Wigren and P. Willars, "Abstraction function for mobile handsets", US Patent 8 831 223, September 9, 2014.
(P66) T. Wigren and I. Siomina, "Nodes and methods for positioning", US Patent 8 855 677, October 7, 2014.
(P67) I. Siomina and T. Wigren, "Method and apparatus for enhancing network testing procedures", US Patent 8 873 408, October 28, 2014.
(P68) T. Wigren and I. Siomina, "Signalling for interference management in HetNets", US Patent 8 880 088, November 4, 2014.
(P69) T. Wigren, "Methods and devices for positioning information reporting", US Patent 8 892 124, November 18, 2014.
(P70) G. C. Goodwin and T. Wigren, "Method and arrangement for scheduling control in a telecommunication system", US Patent 8 902 835, December 2, 2014.
(P71) T. Wigren, "Load estimation for cell stability in interference whitening systems",European Patent EP 2 564 529 (A1), December 10, 2014.
(P72) T. Wigren and A. Kangas, "Pre-scaling of A-GPS positioning accuracy data", US Patent 8 923 886, December 30, 2014.
(P73) I. Siomina, M. Anderson and T. Wigren, "Positioning and location services using civiv address information", US Patent 8 929 918, January 6, 2015.
(P74) T. Wigren and S. Craig, "Uplink load prediction using Kalman filters", US Patent 8 989 036, March 24, 2015.
(P75) T. Wigren, "Dynamic tag control and fingerprinting event localization", European Patent EP2425667 (B1), April 1, 2015.
(P76) T. Wigren, "Interference estimation with TDM", US Patent 9 001 686, April 7, 2015.
(P77) T. Wigren, "Grant utilization based other cell interference estimation" US Patent 9 007 947, April 14, 2015.
(P78) M. Kazmi, M. Israelsson, D. Gerstenberger, T. Wigren and R. Baldemair, "Method and arrangement in a communication system", US Patent 9 020 495, April 28, 2015.
(P79) M. Ringström and T. Wigren, "Reducing interference in a radio communication network", US Patent 9 020 520, April 28, 2015.
(P80) T. Wigren, "Other cell interference estimation", US Patent 9 020 548, April 28, 2015.
(P81) I. Siomina and T. Wigren, "Method and apparatus for use of performance history data in positioning method selection", US Patent 9 026 094, May 5, 2015.
(P82) T. Wigren, D. Gerstenberger, B. Göransson and S. Parkvall, "Dedicated positioning in mobile communication systems", US Patent 9 031 576, May 12, 2015.
(P83) T. Wigren and I. Siomina, "Nodes and methods for positioning", US Patent 9 049 550, June 2, 2015.
(P84) T. Wigren, P. Karlsson and M. Ringström, "Load estimation in softer handover", US Patent 9 055 500, June 9, 2015.
(P85) T. Wigren and C. Muniz Garcia, "Positioning in wireless communication systems", European Patent EP2702815 (B1), July 22, 2015.
(P86) M. Cea, G. C. Goodwin and T. Wigren, "Quantization zooming in inner loop power control", US Patent 9 094 920, July 28, 2015.
(P87) T. Wigren, "Reporting of positioning data", US Patent 9 097 786, August 4, 2015.
(P88) T. Wigren, "Method and arrangement for interference congestion control", US Patent 9 106 319, August 11, 2015.
(P89) T. Wigren, "Method and arrangements for memory efficient estimation of noise floor", US Patent 9 124 367, September 1, 2015.
(P90) I. Siomina and T. Wigren, "Enhancement of positioning quality of service", US Patent 9 151 825, October 6, 2015.
(P91) T. Wigren and I. Siomina, "Method and arrangement for positioning a wireless device", US Patent 9 172 514, October 27, 2015.
(P92) I. Siomina, T. Wigren and M. Andersson, "Method in a UE, a network node and a client node in a wireless communications network", US Patent 9 173 077, October 27, 2015.
(P93) T. Wigren, A. Lamm, K. Johansson, M. Persson and L. Saavolainen, "Slow congestion control", US Patent 9 229 071, December 22, 2015.
(P94) T. Wigren and M. Anderson, "Positioning with split antennas per cell", US Patent 9 247 517, January 26, 2016.
(P95) G. Xinyu, S. Grant, N. Johansson, T. Wigren and Z. Zhang, "Method and network node", US Patent 9 264 316, February 16, 2016.
(P96) A. Persson and T. Wigren, "Load estimation in wireless communication", European Patent EP2476215, February 24, 2016.
(P97) I. Siomina and T. Wigren, "Method and apparatus for communicating location information for enhancing emergency positioning", US Patent 9 277 384, March 1, 2016.
(P98) T. Wigren, "Transcendental function look-up tables for thermal noise power floor estimation", US Patent 9 295 009, March 22, 2016.
(P99) T. Wigren, "Method, apparatus, and system for interference and noise estimation", US Patent 9 301 172, March 29, 2016.
(P100) T. Wigren, H. Egnell and A. Kangas, "Load estimation in frequency domain pre-equalization systems", US Patent 9 307 420, April 5, 2016.
(P101) T. Wigren, "Power control loop stability monitoring", US Patent 9 313 742, April 12, 2016.
(P102) T. Wigren and I. Siomina, "Method and arrangement for load management in heterogeneous networks with interference suppression capable receivers", US Patent 9 319 937, April 19, 2016.
(P103) T. Wigren, "Adaptive load prediction for interference suppression receivers", US Patent 9 320 053, April 19, 2016.
(P104) A. Kangas, A. Lamm and T. Wigren, "Channel estimation in wireless communication systems ", US Patent 9 332 502, May 3, 2016.
(P105) T. Wigren and J. Klerborg, "Thermal noise floor estimation robustness via multi-carrier combining", US Patent 9 332 507, May 3, 2016.
(P106) M. Kazmi, M. Israelsson, D. Gerstenberger, T. Wigren and R. Baldemair, "Method for determining the round trip time", European Patent EP 2272275, June 8, 2016.
(P107) Y. Zhang, E. Shu, T. Wigren and A. Yu, "Wireless communication network for estimating the accuracy of fingerprinting positioning algorithms", US Patent 9 369 986, June 14, 2016.
(P108) T. Wigren, "Supervision of faults in a receiver chain based on noise floor monitoring", US Patent 9 374 179, June 21, 2016.
(P109) I. Siomina and T. Wigren, "Methods and arrangements in a cellular radio communication system", US Patent 9 374 802, June 21, 2016.
(P110) T. Wigren, "Radio network node, a controlling radio network node, and methods therein for enabling management of radio resources in a radio communications network", US Patent 9 386 590, July 5, 2016.
(P111) F. Gunnarsson, K. Johansson and T. Wigren, "Methods and arrangements for handling carrier selection", US Patent 9 398 595, July 17, 2016.
(P112) T. Wigren and C. Muniz Garcia, "Method and arrangement for positioning in wireless communication systems", US Patent 9 408 026, August 2, 2016.
(P113) T. Wigren, "Interference cancellation", US Patent 9 439 201, September 6, 2016.
(P114) I. Siomina and T. Wigren, "Positioning devices and methods in cellular communication systems", US Patent 9 451 575, September 20, 2016.
(P115) G. Xinyu, T. Wigren and Z. Zhang, "A method and a first network node for controlling load", European Patent EP 2 850 889, October 8, 2016.
(P116) T. Wigren, B. Alamshahi, P. Ankel, B. Hogan and P. Karlsson, "Scheduling in cellular communication systems", US Patent 9 480 068, October 25, 2016.
(P117) T. Wigren and A. Kangas, "Method and arrangement for positioning in wireless communication systems", US Patent 9 485 614, November 1, 2016.
(P118) T. Wigren, "Thermal noise power floor estimation", US Patent 9 491 715, November 8, 2016.
(P119) T. Wigren, P. Karlsson, W. Kwong and B. Hogan, "Interference congestion control", US Patent 9 549 408, January 17, 2017.
(P120) T. Wigren. "Other cell interference estimation", US Patent 9 578 535, February 21, 2017.
(P121) Y. Badawi, I. Siomina and T. Wigren, "Prioritizing location request of a certain type in a congestion situation", US Patent 9 585 160, February 28, 2017.
(P122) I. Siomina and T. Wigren, "Fingerprinting with radio channel related information", US Patent 9 594 149, March 14, 2017.
(P123) U. Skärby, P. Ankel, A. Lamm, T. Wigren, H. Egnell, M. Henriksson, B. Hogan, M. Mjögeman, G. Sjöström and Z. Zhang, "A radio base station and a method therein for scheduling uplink resources", US Patent 9 635 674, April 25, 2017.
(P124) T. Wigren, "Interference estimation and devices therefore", European Patent EP 2976921, June 14, 2017.
(P125) Z. Zhang, G. Xinyu and T. Wigren, "Uplink congestion control", US Patent 9 717 057, July 25, 2017.
(P126) T. Wigren, L. Brus, A. Jonsson, K. Lagergren, M. Skarve, "Methods and apparatuses for a data packet flow control for recovering an excessive radio base station buffer dwell time", European Patent EP 3014824, August 9, 2017.
(P127) T. Wigren, "Positioning systems and methods for determining the location of a mobile communication device", US Patent 9 763 217, September 12, 2017.
(P128) T. Wigren, "Method and apparatus relating to interference estimation in cellular communication networks", US Patent 9 794 891, October 17, 2017.
(P129) T. Wigren, K. Johansson, E. Geijer-Lundin and A. Lamm, "Uplink scheduling when using interference suppression", US Patent 9 894 664, February 13, 2018.
(P130) Y. Badawi, I. Siomina and T. Wigren, "Accelerating re-establishment of emergency calls", US Patent 9 955 327, April 24, 2018.
(P131) R. Karaki, T. Dudda, H. Zhang, T. Wigren, H.-L. Maatanen and S. Wager, "Method for controlling transmission of data", US Patent 10 050 894, August 14, 2018.
(P132) T. Wigren, C. M. Garcia and N. Sucevis, "Positioning systems and methods for determining the location of a mobile communication device",US Patent 10 051 409, August 14, 2018.
(P133) T. Wigren and M. Wang, "Positioning systems and methods for determining the location of a mobile communication device", US Patent 10 051 424, August 14, 2018.
(P134) T. Wigren and D. Sandberg, "Radio network node and method performed therein", US Patent 10 177 865, January 8, 2019.
(P135) T. Wigren and S. Craig, "Method, apparatus and system for interference metric signalling", US Patent 10 225 034, March 5, 2019.
(P136) G. Levin, M. Parwan and T. Wigren, "Automatic receiver chain supervision", European Patent EP 3449586, March 6, 2019.
(P137) Y. Badawi, T. Wigren and I. Siomina, "Wireless device, network node and methods performed thereby for reporting and logging an event", US Patent 10244 420, March 26, 2019.
(P138) M. Wang and and T. Wigren, "Fingerprint positioning for mobile terminals", US Patent 10 356 741, July 16, 2019.
(P139) T. Wigren and M. Åhlander, "Apparatuses, methods, computer programs, and computer program products for interference avoidance", US Patent 10 455 591, October 22, 2019.
(P140) Y. Zhao, Y. Sun and T. Wigren, "Method and base station for determining an uplink power control target", European Patent EP 3375226, October 23, 2019.
(P141) Y. Sun and and T. Wigren, "Computer program, computer-readable storage medium, access point, wireless device and methods performed therein", US Patent 10 470 206, November 5, 2019.
(P142) T. Wigren, R. Karaki, T. Dudda and A. Vesely, "Technique for multi-connectivity",European Patent EP 3348027, November 20, 2019.
(P143) T. Wigren, R. Middleton and L. Brus, "Multipoint data flow control", US Patent 10 547 557, January 28, 2020.
(P144) T. Wigren and O. Mauritz, "5G beamforming functionality", US Patent 10 554 278, February 4, 2020.
(P145) T. Wigren, J. Bergman and A. Kangas, "Control link definition in networked control system", European Patent EP 3437420, April, 2020.
(P146) T. Wigren, K. Lau, R. Delgado and R. Middleton, "Interval time control for 5G multi-connectivity", European Patent, EP 3476163, April, 2020.
(P147) T. Wigren, K. Lau, R. Delgado, R. Middleton, W. Muller and Y. Sung, "Management of 5G split bearer flow control", US Patent 10 694 425, June 23, 2020.
(P148) T. Wigren, R. Middleton, R. Delgado and K. Lau, "Centralized multi-node flow control for 5G multi-connectivity", European Patent EP 3434043, June, 2020.
(P149) C. Faronius, B. Göransson, F. Huss, M. Lundevall and T. Wigren, "Network node and method performed thereby for scheduling transmissions between the network node and one or more wireless devcices", US Patent 10 742 301, August 11, 2020.
(P150) K. Lau, R. Delgado, R. Middleton and T. Wigren, "Flow control in wireless communication systems", US Patent 10 743 214, August 11, 2020.
(P151) C. Faronius and T. Wigren, "Overlaid-coded beamforming", US Patent 10 771 136, September 8, 2020.
(P152) F. Gunnarsson, H. Ryden, M. Wang and T. Wigren, "Communication nodes and methods therein forpositioning in a wireless communications network", US Patent 10 805 898, October 13, 2020.
(P153) A. Kangas, B. Nordström and T. Wigren, "Methods and devices for handling transmissions with non-orthogonality losses", US Patent 10 931 351, February 23, 2021.
(P154) T. Wigren, A. Kangas and J. Bergman, "Method and nodes for configuration of a wireless link", US Patent 10 931 520, February 23, 2021.
(P155) T. Wigren, K. Lau, R. Middleton and R. Delgado, "Round trip time skew control methods and arrangements", US Patent 10 944 678, March 9, 2021.
(P156) T. Wigren and S. Murali Krishna, "Wireless-system flow control and packet scheduler interface", US Patent 10 999 185, May 4, 2021.
(P157) T. Wigren and M. Wang, "Fingerprinting enhancement with multi-band AoA measurements", US Patent 11 026 242, June 1, 2021.
(P158) T. Wigren and A. Kangas, "Steering vector weighting", US Patent 11 044 001, June 22, 2021.
(P159) A. Kangas, H. Egnell and T. Wigren, "Robust MU-MIMO transmission using virtual UEs", US Patent 11 050 467, June 29, 2021.
(P160) T. Wigren, M. Skarve and M. Wittberg, "Flow control in wireless communication systems", US Patent 11 129 055, September 21, 2021.
(P161) T. Carlsson, H. Sahlin and T. Wigren, "Cost efficient PRACH detection", US Patent 11 129 209, September 21, 2021.
(P162) T. Wigren and O. Mauritz, "Methods and devices for determining suitable transmit directions for beamformed transmission", US Patent 11 184 068, November 23, 2021.
(P163) R. Delgado, K. Lau, R. Middleton, I. Siomina and T. Wigren, "First network node methods therein for handling directions of transmission of beamformed beams", US Patent 11 296 765, April 5, 2022.
(P164) S. Bergman, G. Jöngren and T. Wigren, "Controlling transmitter output", US Patent 11 362 713, June 14, 2022.
(P165) T. Wigren, B. Hogan, A. Langereis, Y. Pei, Y. Wang and C. Törnevik, "Controlling transmitter output in a wireless communication network based on regulatory RF exposure limits", US Patent 11 412 523, August 9, 2022.
(P166) T. Wigren, R. Delgado, R. Karlsson, K. Lau and R. Middleton, "Efficient beam searching", US Patent 11 418 974, August 16, 2022.
(P167) T. Wigren, "Signaling of scaled 3D position information", US Patent 11 480 646, October 25, 2022.
(P168) T. Wigren, "Scaled TDOA 3D positioning", US Patent 11 486 959, November 1, 2022.
(P169) J. Karlsson, Y. Pei, Y. Wang and T. Wigren, "Transmission power determination for an antenna array", US Patent 11 503 548, November 15, 2022.
(P170) Y. Pei, Y. Wang, T. Wigren and B. Thors, "Method and apparatus for power control", US Patent 11 564 182, January 24, 2023.
(P171) S. Yasini and T. Wigren, "Drone state estimation by single base station", Taiwanese Patent I793495, February 21, 2023.
(P172) B. Thors, C. Törnevik and T. Wigren, "Controlling transmitter output", US Patent 11 595 071, February 28, 2023.
(P173) S. Guo and T. Wigren, "Controlling total average transmission power of a radio base station", European Patent EP 3 977 784 B1, March 29, 2023.
(P174) B. Hogan and T. Wigren, "Transmission power control for a radio base station", US Patent 11 722 967, August 8, 2023.
(P175) Y. Pei and T. Wigren, "Controlling transmitter output", US Patent 11 723 014, August 8, 2023.
(P176) T. Wigren, "Transmission power control of a radio base station", US Patent 11 743 835, August 29, 2023.
(P177) T. Wigren and J. Karlsson, "Methods, apparatus and machine-readable medium relating to adjustment of beam gain in wireless communication", US Patent 11 777 564, October 13, 2023.
(P178) K. Zhu, I Siomina and T. Wigren, "Method and apparatus for indoor mapping, positioning, or navigation", US Patent 11 815 357, November 14, 2023.
(P179) T. Wigren and A. Kangas, "Steering vector weighting for ZF backhaul transmission", US Patent 11848732, December 19, 2023.
(P180) J. Thorebäck, M. Nilsson, T. Wigren and B. Göransson, "Power control", US Patent 11902903, February 13, 2024.
(P181) T. Wigren, B. Hogan and W. Muller, "Coordinating control of average EIRP of multiple radio transmitters", US Patent 11956727, April 9, 2024.
(P182) S. Yasini, T. Wigren and P. Persson, "Sharing of user equipment states", US Patent 11960020, April 16, 2024.
(P183) S. Yasini and T. Wigren, "Device type state estimation", US Patent 11963130, April 16, 2024.
(P184) S. Yasini, R. H. Middleton and T. Wigren, "User equipment kinematic state estimation", US Patent 11979851, May 7, 2024.
(P185) T. Wigren, "Control of EIRP of a radio base station", US Patent 12003294 , June 4, 2024.
(P186) P. Blomberg, C. Törnevik, T. Wigren and M. Wittberg, “Uplink power control of a terminal device'2, US Patent 12010627, June 11, 2024.
(P187) T. Wigren, “Methods, apparatus and machine-readable mediums relating to adjusting beam gain in wireless communication networks”, US Patent 12015461, June 18, 2024.
(P188) J. Ahlgren, B. Göransson, J. Karlsson, M. Malmberg, M. Nilsson and T. Wigren, “Narrowband AAS receiver with data replay interfacing”, US Patent 12028138, July 2, 2024.
(P189) I. Siomina, T. Wigren and S. Yasini, “Methods for detecting and managing bidirectional timing measurements in NR”, US Patent 12028826, July 2, 2024.
(P190) T. Wigren, Y. Sung, R. A. Delgado, K. Lau and R. H. Middleton, “Methods, apparatus and machine-readable media relating to transmission and reconstruction of data streams using data duplication”, US Patent 12034644, July 9, 2024.
(P191) T. Wigren, R. Delgado, R. H. Middleton and K. Lau, “Stable multipoint alignment”, US Patent 12082141, September 3, 2024.
(P192) T. Wigren, S. Guo and K. Huisman, “Average EIRP regulation interval enhancement by time blanked scheduling”, US Patent 12096381, September 17, 2024.
(P193) T. Wigren and C. Törnevik, “Methods and apparatuses for coordinated control of average EIRP”, US Patent 12108347, October 1, 2024.
(P194) Y. Sun and T. Wigren, “Multiplexed transmission of data packages towards a terminal device”, US Patent 12113731, October 8, 2024.
(P195) T. Wigren, S. Yasini and I. Siomina, ”User equipment state estimation", US Patent 12143958, November 12, 2024.
Standardization Documents
(St1) T. Wigren and P.Stahlfjäll, Ericsson Radio Systems AB, "IPDL simulations for time mask evaluation", R4-020118 , 3GPP TSG-RAN Working Group 4, meeting 21, Sophia Antipolis, France, Jan. 28-Feb. 1, 2002.
(St2) T. Wigren, Ericsson, "IPDL attenuation and SFN--SFN type 2 measurement sensitivity", R4-0200806 , 3GPP TSG-RAN Working Group 4, meeting 23, Gyeongju, South Korea, May 13-17, 2002.
(St3) T. Wigren, Ericsson, "Required window size for measurements using IPDL", R4-021462 , 3GPP TSG-RAN Working Group 4, meeting 25, Secucus, New Jersey, USA, November 11-15, 2002.
(St4) T. Wigren, Ericsson, "A-GPS sensitivity and node B time stamping accuracy", R4AH-04008 , 3GPP TSG-RAN Working Group 4 A-GPS Ad Hoc Meeting, Espoo, Finland, January 28-29, 2004.
(St5) T. Wigren, Ericsson, "Expected performance of OTDOA-IPDL positioning - initial indications based on live measurements", R1-040567 , 3GPP TSG-RAN Working Group 1, Meeting 37, Montreal, Canada, May 10-14, 2004.
(St6) J. Bergström and T. Wigren, Ericsson, "Positioning reporting inconsistencies", R2-042145 , 3GPP TSG-RAN Working Group 2, Meeting 44, Sophia Antipolis, France, Oct. 4-8, 2004.
(St7) P.-A. Stenberg and T. Wigren, Ericsson, "Positioning reporting inconsistencies", G2-040531 , 3GPP TSG- GERAN Working Group 2, Meeting 21, St Paul's Bay, Malta, Oct. 4-8, 2004.
(St8) T. Wigren, Ericsson, "Required scope for introduction of A-GNSS", GP-060210 , 3GPP TSG- GERAN 28, Brussels, Belgium, January, 2006.
(St9) T. Wigren, Ericsson, "Positioning reporting inconsistencies", R2-060404 , 3GPP TSG-RAN Working Group 2, Meeting 51, Denver, Colorado, USA, Feb. 13-17, 2006.
(St10) T. Wigren, Ericsson, "Positioning reporting inconsistencies", R3-060220 , 3GPP TSG-RAN Working Group 3, Meeting 51, Denver, Colorado, USA, Feb. 13-17, 2006.
(St11) T. Wigren and S. Ekemark, Ericsson, "Positioning reporting inconsistencies", R2-061391 , 3GPP TSG-RAN Working Group 2, Meeting 53, Shanghai, China, May 8-12, 2006.
(St12) T. Wigren and S. Ekemark, Ericsson, "Change request", R2-061392 , 3GPP TSG-RAN Working Group 2, Meeting 53, Shanghai, China, May 8-12, 2006.
(St13) T. Wigren and M. Israelsson, Ericsson, "Positioning reporting inconsistencies", R3-060715 , 3GPP TSG-RAN Working Group 3, Meeting 52, shanghai, China, May 8-12, 2006.
(St14) T. Wigren and M. Israelsson, Ericsson, "Change request", R3-060716 , 3GPP TSG-RAN Working Group 3, Meeting 52, Shanghai, China, May 8-12, 2006.
(St15) T. Wigren and K. Sjerling, Ericsson, "Methodology for UTDOA LMU performance specification", R4-060447 , 3GPP TSG-RAN Working Group 4, Meeting 39, Shanghai, China, May 8-12, 2006.
Presentations
(Pr1) T. B. Minde, T. Wigren, J. Ahlberg and H. Hermansson, "Techniques for low bit rate speech coding using long analysis frames", Proc. ICASSP, Minneapolis, Minnesota, U.S.A., 1993.
(Pr2) T. Wigren, "Static nonlinearities in recursive system identification", Department of Automatic Control, Lund Institute of Technology, Lund, Sweden, April 5, 1995.
(Pr3) T. Wigren, "Static nonlinearities in recursive system identification", Department of Applied Electronics, Chalmers University of Technology, Gothenburg, Sweden, May 23, 1995.
(Pr4) T. Wigren, "Static nonlinearities in recursive system identification", Department of Signals, Sensors and Systems, Royal Institute of Technology, Stockholm, Sweden, June 8, 1995.
(Pr5) T. Wigren and H. Egnell, "Automatic target identification and multi-sensor data fusion in air defense command and control systems", Milinf 1996 , Swedish Defense Material Organization, Enköping, Sweden, June 1996.
(Pr6) T. Wigren and P. Händel, "Harmonic signal modeling using adaptive nonlinear function estimation", ICASSP, Atlanta, Georgia, U.S.A., 1996.
(Pr7) S. Halvarsson, T. Wigren and B. Wahlberg, "A test statistics for low complexity change detection in dynamic systems based on averaged filter models", ICASSP , Atlanta, Georgia, U.S.A., 1996.
(Pr8) T. Wigren, "Noncooperative target type identification in multi-sensor tracking", IRCTR Colloquium on Surveillance Sensor Tracking , Delft Technical University, Delft, the Netherlands, June 26, 1997.
(Pr9) T. Wigren, "Target type probability combining algorithms for multi-sensor tracking", Aerosense 2001, SPIE, Orlando, FL, April 16-20, 2001.
(Pr10) T. Wigren, "Remote aircraft type probability estimation and combining using distributed sensors - an application of Bayesian estimation", Docent Lecture, Uppsala University, Uppsala, Sweden, September 25, 2001.
(Pr11) T. Wigren, "User choices and model validation in system identification using nonlinear Wiener models", 13:th IFAC Symposium on System Identification, Rotterdam, The Netherlands, August 27-29, 2003.
(Pr12) T. Wigren, "Recursive identification based on nonlinear state space models applied to drum-boiler dynamics with nonlinear output equations", ACC, Portland, Oregon, USA, June 8-10, 2005.
(Pr13) T. Wigren, "Scaling of the sampling period in nonlinear system identification", ACC, Portland, Oregon, U.S.A., June 8-10, 2005.
(Pr14) T. Wigren and P. Hellqvist, "Estimation of uplink WCDMA load in a single RBS", IEEE VTC, Baltimore, USA, 2007.
(Pr15) T. Wigren and L. Brus, "Feedforward control of a nonlinear solar collector plant with long and varying delays", Seminar, 2008.
(Pr16) T. Wigren, "Identification using nonlinear Wiener models", Seminar, University of Porto, Porto, Portugal, 2008.
(Pr17) T. Wigren, "Recursive identification of continuous time nonlinear state space models", Seminar, University of Porto, Porto, Portugal, 2008.
(Pr18) T. Wigren and J. Wennervirta, "RTT positioning in WCDMA", 5th International Conference on Wireless and Mobile Communications, ICWMC 2009, Cannes/La Bocca, France, August 23-29, 2009.
(Pr19) L. Shi and T. Wigren, "AECID fingerprinting positioning performance", Globecomm, Honolulu, HI, 2009.
(Pr20) T. Wigren, "Clustering and polygon merging algorithms for fingerprinting positioning in LTE", ICSPCS, Honolulu, HI, December 12-14, 2011.
(Pr21) T. Wigren, "Low complexity Kalman filtering for inter-cell interference and power based load estimation in the WCDMA uplink", ICSPCS, Honolulu, HI, December 12-14, 2011.
(Pr22) T. Wigren, A. Kangas, Y. Jading, I. Siomina and C. Tidestav, "Enhanced WCDMA fingerprinting localization using OTDOA position measurements from LTE", IEEE VTC Fall, Quebec City, Canada, September 3-6, 2012.
(Pr23) M. G. Cea, G. C. Goodwin and T. Wigren, "Model Predictive Zooming Power Control in Future Cellular Systems Under Coarse Quantization", IEEE VTC Fall, Quebec City, Canada, September 3-6, 2012.
(Pr24) T. Wigren. "LTE fingerprinting localization with altitude", IEEE VTC Fall, Quebec City, Canada, September 3-6, 2012.
(Pr25) T. Wigren and J. Schoukens, "Three free data sets for development and benchmarking in nonlinear system identification", ECC, Zurich, Switzerland, July 17-19, 2013.
(Pr26) T. Wigren, "Low-frequency limitations in saturated and delayed networked control", IEEE CCA 2015, Sydney, Australia, Sep. 21-23, 2015.
(Pr27) T. Wigren, "Nonlinear identification of neuron models", IEEE CCA, Sydney, Australia, Sep. 21-23, 2015.
(Pr28) T. Wigren, "Wireless data flow control limitations and design", Seminar, University of Newcastle, NSW, Australia, October 7, 2015.
(Pr29) T. Wigren, "New results in nonlinear networked control and system identification", University of New South Wales, Sydney, Australia, Oct. 16, 2015.
(Pr30) T. Wigren, "Positioning in LTE and 5G", Seminar, University of Newcastle, NSW, Australia, December 4, 2017.
(Pr31) K. Lau, R. Delgado, T. Wigren and R. Middleton, "Disturbance rejection properties for a 5G networked data flow delay controller", IEEE-CDC, Melbourne, Victoria, Australia, December 12-15, 2017.
(Pr32) T. Wigren, "Networked and delayed recursive identification of nonlinear systems", IEEE CDC, Melbourne, Australia, Dec. 12-15, 2017.
(Pr33) T. Wigren, "Location technology in cellular systems", Seminar, Department of Information Technology, Uppsala University, Uppsala, Sweden, February 13, 2018.
(Pr34) T. Wigren, "Wireless hybrid positioning based on surface modeling with polygon support", IEEE VTC-Fall 2019, Porto, Portugal, September 2019.
(Pr35) T. Wigren, "Stable logarithmic control of a disturbance", Reglermöte, Luleå, Sweden, June, 2022.
(Pr36) T. Wigren, "Why reinforcement learning needs to account for an old enemy of feedback", Micro-seminar, Department of Information Technology, Uppsala University, 2023.
(Pr37) T. Wigren, "Fifteen minutes on averaging theory for recursive algorithms", Micro-seminar, Department of Information Technology, Uppsala University, March 28, 2024.
(Pr38) T. Wigren, "Logarithmic feedback control of passive interference", European Control Conference, Stockholm, Sweden, June 25-28, 2024.
(Pr39) T. Wigren, "Convergence in delayed recursive identification of nonlinear systems", European Control Conference, Stockholm, Sweden, June 25-28, 2024.
(Pr40) ) T. Wigren, "Delay attack and detection in feedback linearized control systems", European Control Conference, Stockholm, Sweden, June 25-28, 2024.
Implemementation:
[DA] - in D-AMPS
[EC] - in echo canceller
[ATC] - in ATC MRT
[NB] - in Node B
[RNC] - in RNC
[SAS] - in SAS
[ENB] - in eNB
[ESMLC] - inE SMLC
[GNB] - in gNB