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Karlsson, Magnus, DocentORCID iD iconorcid.org/0000-0002-4136-0817
Publications (10 of 54) Show all publications
Liu, Y., Hassan, K. A., Karlsson, M., Pang, Z. & Gong, S. (2019). A Data-Centric Internet of Things Framework Based on Azure Cloud. IEEE Access, 7, 53839-53858
Open this publication in new window or tab >>A Data-Centric Internet of Things Framework Based on Azure Cloud
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2019 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 53839-53858Article in journal (Refereed) Published
Abstract [en]

Internet of Things (IoT) has been found pervasive use cases and become a driving force to constitute a digital society. The ultimate goal of IoT is data and the intelligence generated from data. With the progress in public cloud computing technologies, more and more data can be stored, processed and analyzed in cloud to release the power of IoT. However, due to the heterogeneity of hardware and communication protocols in the IoT world, the interoperability and compatibility among different link layer protocols, sub-systems, and back-end services have become a significant challenge to IoT practices. This challenge cannot be addressed by public cloud suppliers since their efforts are mainly put into software and platform services but can hardly be extended to end devices. In this paper, we propose a data-centric IoT framework that incorporates three promising protocols with fundamental security schemes, i.e., WiFi, Thread, and LoRaWAN, to cater to massive IoT and broadband IoT use cases in local, personal, and wide area networks. By taking advantages of the Azure cloud infrastructure, the framework features a unified device management model and data model to conquer the interoperability challenge. We also provide implementation and a case study to validate the framework for practical applications.

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
Internet of Things, Cloud computing, Protocols, Wireless fidelity, Broadband communication, Monitoring, Interoperability, framework, cloud, azure, IoT hub, thread, WiFi, lorawan
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:liu:diva-156704 (URN)10.1109/ACCESS.2019.2913224 (DOI)000467047300001 ()
Note

Funding agencies:  Swedish Environmental Protection Agency; Norrkoping Fund for Research and Development, Sweden

Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-08-21
Liu, Y., Hassan, K. A., Karlsson, M., Weister, O. & Gong, S. (2018). Active Plant Wall for Green Indoor Climate Based on Cloud and Internet of Things. IEEE Access, 6, 33631-33644
Open this publication in new window or tab >>Active Plant Wall for Green Indoor Climate Based on Cloud and Internet of Things
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2018 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 33631-33644Article in journal (Refereed) Published
Abstract [en]

An indoor climate is closely related to human health, well-being and comfort. Thus, indoor climate monitoring and management are prevalent in many places, from public offices to residential houses. Our previous research has shown that an active plant wall system can effectively reduce the concentrations of particulate matter and volatile organic compounds and stabilize the carbon dioxide concentration in an indoor environment. However, regular plant care is restricted by geography and can be costly in terms of time and money, which poses a significant challenge to the widespread deployment of plant walls. In this article, we propose a remote monitoring and control system that is specific to the plant walls. The system utilizes the Internet of Things technology and the Azure public cloud platform to automate the management procedure, improve the scalability, enhance user experiences of plant walls, and contribute to a green indoor climate.

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:liu:diva-148850 (URN)10.1109/ACCESS.2018.2847440 (DOI)
Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2019-08-21
Wu, D., Serban, A., Karlsson, M. & Gong, S. (2018). Highly Unequal Three-Port Power Divider: Theory and Implementation. International Journal of Antennas and Propagation, Article ID 9141964.
Open this publication in new window or tab >>Highly Unequal Three-Port Power Divider: Theory and Implementation
2018 (English)In: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, article id 9141964Article in journal (Refereed) Published
Abstract [en]

A three-port power divider consisting of a directional coupler, a Wilkinson power divider, and two transmission lines connected to them is proposed. Theoretical analysis reveals that highly unequal power division can be achieved by a feedback mechanism of two transmission lines along with the coupling coefficient of the directional coupler and the power division ratio of the Wilkinson power divider. The three-port power divider inherits the performance characteristics of high isolation, low reflection coefficients at all ports, and the minimum number of components. The proposed power divider is designed at 5.8 GHz and fabricated and evaluated through measurements. It demonstrates that electromagnetic simulation results are in good agreement with theoretical prediction and measurement results. The three-port power divider is compact in the planar form, so it can be easily integrated into radio frequency front ends.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-149999 (URN)10.1155/2018/9141964 (DOI)000440492900001 ()
Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2019-06-17
Gong, S., Östh, J., Serban, A. & Karlsson, M. (2016). Six-port Modulators for High Speed Data. In: GigaHertz Symposium 2016: . Paper presented at Swedish Microwave Days (pp. 65). Linköping
Open this publication in new window or tab >>Six-port Modulators for High Speed Data
2016 (English)In: GigaHertz Symposium 2016, Linköping, 2016, p. 65-Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Results from our recent study on six-port modulators and demodulators for high speed data transmission have shown that the six-port radio technology has the potential to catch up the speed of the Internet. This is due to the fact that the binary baseband data, either electrical or optical, can be converted directly to high order modulated RF signal without any D/A conversion. The six-port modulators and demodulators can also be designed with differential circuitry to improve the signal-to-noise ration and dynamic range. In addition, antennae and radio front-end components can be integrated on the same substrate with the six-port modulator and demodulator.

Place, publisher, year, edition, pages
Linköping: , 2016
Keywords
six-port radio, six-port modulator, high speed data transmission
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-129187 (URN)
Conference
Swedish Microwave Days
Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2019-06-17
Östh, J., Karlsson, M., Serban, A. & Gong, S. (2015). A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications. IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 62(2), 564-570
Open this publication in new window or tab >>A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications
2015 (English)In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 62, no 2, p. 564-570Article in journal (Refereed) Published
Abstract [en]

If present, nonlinear effects in a six-port modulator cause distortion and degradation of the quality of the modulated output waveform. How nonlinear effects occur and their impact on system performance were derived in a mathematical model. The model shows that non-ideal performance of the passive six-port correlator is the main contributor to nonlinear distortion. Simulations and measurements on two manufactured six-port modulators were used to validate the theory and to give deeper insight on system performance. It is shown that by using a differentially signaled six-port modulator instead of a single-ended six-port modulator, better performance is achieved over a wide bandwidth. For an error vector magnitude of less than 10%, the relative bandwidth was measured to 12% for the single-ended but 30% for the differentially signaled modulator

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2015
Keywords
Differential; modulation order; non-linearity; single-ended; six-port; six-port correlator; six-port modulator
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-115331 (URN)10.1109/TCSI.2014.2362310 (DOI)000349399800025 ()
Available from: 2015-03-13 Created: 2015-03-13 Last updated: 2019-08-12Bibliographically approved
Mohsin, I., Karlsson, M. & Gong, S. (2014). Frequency diplexer network for wireless parallel data transmission and ultrawideband systems utilizing manifold technique. Microwave and optical technology letters (Print), 56(8), 1869-1871
Open this publication in new window or tab >>Frequency diplexer network for wireless parallel data transmission and ultrawideband systems utilizing manifold technique
2014 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 56, no 8, p. 1869-1871Article in journal (Refereed) Published
Abstract [en]

A frequency diplexer network for ultrawideband radios focused on wireless parallel data transmission is presented. It has a combination of two bandpass filters utilizing manifold multiplexing technique. In the frequency band 6-9 GHz, two flat sub-bands at center frequencies 6.7 and 8.3 GHz have been achieved with respect to forward transmission, input reflection, and group delay. A maximum group delay variation of 0.6 ns was measured in the sub-bands. For low cost and simple circuit implementation, the design is implemented using the microstrip technology.

Place, publisher, year, edition, pages
John Wiley & Sons, 2014
Keywords
diplexer; frequency division multiplexing; manifold multiplexing; ultrawideband; microstrip technology
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-109116 (URN)10.1002/mop.28464 (DOI)000337529700037 ()
Available from: 2014-08-13 Created: 2014-08-11 Last updated: 2019-09-09Bibliographically approved
Asghar, A. M., Malick, M., Karlsson, M. & Hussain, A. (2013). A multiwideband planar monopole antenna for 4G devices. Microwave and optical technology letters (Print), 55(3), 589-593
Open this publication in new window or tab >>A multiwideband planar monopole antenna for 4G devices
2013 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 55, no 3, p. 589-593Article in journal (Refereed) Published
Abstract [en]

This article presents a compact multiband planar antenna designed for mobile phone applications.The antenna performance is achieved by designing a planar monopole antenna into distributed radiating elements. The proposed antenna is comprised of a chopped circular radiator appended with a meander line and an L-strip coupled element, which is an extension of the ground plane. The combination of a chopped circular patch and L-shaped coupling strip residing on the top side generates lower band while upper band resonances are attained separately by chopped circular resonator and meander line elements. The antenna shows a planar structure which occupies an area of 56 x 17.6 mm and can be directly printed onto a circuit board at low cost making it especially suitable for mobile phone applications. The manufactured antenna is experimentally verified and covers several wireless communication bands, such as LTE 750, GSM 850, GSM 900, DCS, UMTS-2110, Bluetooth, WLAN, WiMAX, and UWB. The high frequency structure simulation is used to design and analyze the antenna performance, and a practical structure was fabricated and tested. The measured and simulated return loss show good agreement.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2013
Keywords
mobile phone, wireless communication bands, multiband planar antenna, meander line, modified ground plane, LTE
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-89800 (URN)10.1002/mop.27360 (DOI)000314214500035 ()
Available from: 2013-03-07 Created: 2013-03-07 Last updated: 2019-09-09Bibliographically approved
Mohsin, I., Karlsson, M., Owais, O. & Gong, S. (2013). Design and implementation of a UWB six-port correlator for 6-9 GHz frequency band. Microwave and optical technology letters (Print), 55(1), 190-193
Open this publication in new window or tab >>Design and implementation of a UWB six-port correlator for 6-9 GHz frequency band
2013 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 55, no 1, p. 190-193Article in journal (Refereed) Published
Abstract [en]

A compact size six-port correlator using bandwidth enhancing stubs for the 69 GHz ultra wideband radio is presented. The proposed six-port has a center frequency of 7.5 GHz with 50% relative bandwidth. The correlator is based entirely on microstrip technology for low cost and simple circuit implementation.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2013
Keywords
branch line coupler; six-port correlator; ultra wideband; microstrip technology; miniaturization
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-87198 (URN)10.1002/mop.27235 (DOI)000311386700049 ()
Available from: 2013-01-14 Created: 2013-01-14 Last updated: 2019-09-19
Karlsson, M., Serban, A., Östh, J., Owais, O. & Gong, S. (2013). Frequency Triplexer for Ultra-Wideband Systems (6–9 GHz). IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 60(3), 540-547
Open this publication in new window or tab >>Frequency Triplexer for Ultra-Wideband Systems (6–9 GHz)
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2013 (English)In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 60, no 3, p. 540-547Article in journal (Refereed) Published
Abstract [en]

A triplexer for ultra-wideband radio implemented entirely with distributed microstrips is presented. The triplexer is composed of a triplex junction network and three bandpass filters. The circuit is integrated in a flex-rigid printed circuit board. Three flat 1 GHz sub-bands in the frequency band 6-9 GHz have been achieved. The group delay variation within each 1 GHz sub-band was measured to be less than 0.4 ns. A good agreement between simulation and measurement was obtained, e.g., less than 0.3 dB difference in the forward transmission in the majority of the frequency band.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2013
Keywords
Bandpass filter, broadside-coupled, edge-coupled, frequency multiplexing, triplexer, UWB
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-90756 (URN)10.1109/TCSI.2012.2215743 (DOI)000315959100003 ()
Note

Funding Agencies|Sony Mobile Communications AB||Ericsson AB||Vinnova in Sweden||

Available from: 2013-04-08 Created: 2013-04-05 Last updated: 2019-06-17Bibliographically approved
Östh, J., Karlsson, M., Serban, A. & Gong, S. (2013). M-QAM Six-Port Modulator Using Only Binary Baseband Data, Electrical or Optical. IEEE transactions on microwave theory and techniques, 61(6), 2506-2513
Open this publication in new window or tab >>M-QAM Six-Port Modulator Using Only Binary Baseband Data, Electrical or Optical
2013 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 61, no 6, p. 2506-2513Article in journal (Refereed) Published
Abstract [en]

A new circuit architecture for a direct-carrier six-port modulator is proposed. The proposed architecture uses parallel binary-valued baseband signals to control binary-valued impedance loads for generation of rectangular M-QAM modulation. A theoretical model of the proposed modulator is also derived. A prototype modulator for 64 quadrature amplitude modulation is designed and fabricated for a center frequency of 2.5 GHz for verification of the proposed architecture. The measurements verify the theory and show that good performance can be obtained with the proposed architecture. The proposed modulator does not require any digital-to-analog converter and can operate with both electrical and optical control signals.

Place, publisher, year, edition, pages
IEEE, 2013
Keywords
Binary baseband; carrier leakage suppression; direct-carrier modulator; six-port correlator
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-96474 (URN)10.1109/TMTT.2013.2259255 (DOI)000319979300024 ()
Available from: 2013-08-23 Created: 2013-08-20 Last updated: 2019-06-17Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4136-0817

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