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Sternad, Mikael
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Publications (10 of 76) Show all publications
Phan Huy, D.-T., Wesemann, S., Björsell, J. & Sternad, M. (2018). Adaptive massive MIMO for fast moving connected vehicles: It will work with predictor antennas!. In: : . Paper presented at 22nd International ITG Workshop on Smart Antennas (WSA2018), Bochum, Tyskland.
Open this publication in new window or tab >>Adaptive massive MIMO for fast moving connected vehicles: It will work with predictor antennas!
2018 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-363241 (URN)
Conference
22nd International ITG Workshop on Smart Antennas (WSA2018), Bochum, Tyskland
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2018-10-15
Zirwas, W., Sternad, M. & Apelfröjd, R. (2017). Key solutions for a massive MIMO FDD system. In: 2017 IEEE 28TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC): . Paper presented at IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), OCT 08-13, 2017, Montreal, Kanada. IEEE
Open this publication in new window or tab >>Key solutions for a massive MIMO FDD system
2017 (English)In: 2017 IEEE 28TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE, 2017Conference paper, Published paper (Refereed)
Abstract [en]

The ongoing standardization within 3GPP for the so called new radio (NR) system has identified massive multiple-input multiple output (MIMO) transmission, also called full dimension MIMO, as one of the main contributors to higher spectral efficiency for the mobile broadband case. In particular for radio frequencies below 6 GHz, channel estimation has to be supported in frequency division duplex (FDD) as well as time division duplex (TDD) operation. In TDD we may obtain downlink channels by estimating uplink channels, assuming reciprocity. For FDD, codebook based design as well as some type of explicit feedback is under discussion. Separately, there are also ongoing discussions of the question if massive MIMO in combination with FDD is a reasonable choice at all. Here we highlight some of our recent results obtained within several 5G research projects. To our understanding they overcome some of the inherent limitations of massive MIMO for FDD. As indicated by simulations, the resulting concept enables a grid of beam (GoB) and reference signal design with a reasonable downlink reference signal overhead of around 10 percent, together with reasonable feedback overhead of several hundred kbit/s per UE. Such a design attains around 90 percent of the massive MIMO system performance with ideal channel state information.

Place, publisher, year, edition, pages
IEEE, 2017
National Category
Signal Processing
Identifiers
urn:nbn:se:uu:diva-330698 (URN)10.1109/PIMRC.2017.8292395 (DOI)000426970901083 ()978-1-5386-3531-5 (ISBN)
Conference
IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), OCT 08-13, 2017, Montreal, Kanada
Funder
EU, European Research Council, ICT-671660
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2018-08-09Bibliographically approved
Björsell, J., Sternad, M. & Grieger, M. (2017). Predictor antennas in action. In: 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): . Paper presented at IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 8-13 Oct. 2017, Montreal, Kanada. IEEE
Open this publication in new window or tab >>Predictor antennas in action
2017 (English)In: 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), IEEE, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Connected vehicles in large numbers will be expensive in terms of power and bandwidth unless advanced transmit schemes are employed. These would rely on channel state information at transmitter (CSIT), which rapidly becomes outdated for fading vehicular channels. We here evaluate the predictor antenna concept, that solves this problem by using antennas on the outside of vehicles, with one extra antenna in front of the others. Its estimated channel is a scaled prediction for the channels encountered by rearward antennas when they reach that position. We evaluate this concept on a large set of channel sounding measurements from an urban environment. Recent investigations of the correlations of these measurements indicate that the average normalized mean squared errors (NMSEs) of the complex valued channel predictions should be around -10 dB for prediction horizons in space of up to 3 wavelengths. This represents an extension of the attainable prediction horizon by an order of magnitude, as compared to Kalman or Wiener extrapolation of past channel measurements. It represents an accuracy that would enable e.g. accurate massive multiple input multiple output (MIMO) downlink beamforming to vehicles. We here perform predictions on a subset of the measurements with good channel-to-estimation error power ratio (SNR). The approximate true channels are here available and we evaluate the performance on a validation data set. The results confirm that the distribution of the NMSE, over all investigated propagation environments, is close to that obtained by correlation-based models and outperforms the use of outdated channel measurements.

Place, publisher, year, edition, pages
IEEE, 2017
National Category
Signal Processing
Identifiers
urn:nbn:se:uu:diva-330699 (URN)10.1109/PIMRC.2017.8292235 (DOI)000426970900072 ()978-1-5386-3531-5 (ISBN)
Conference
IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 8-13 Oct. 2017, Montreal, Kanada
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2018-08-10Bibliographically approved
Phan-Huy, D.-T., Sternad, M., Svensson, T., Zirwas, W., Villeforceix, B., Karim, F. & El-Ayoubi, S.-E. -. (2016). 5G on Board: How Many Antennas Do We Need on Connected Cars?. In: 2016 IEEE GLOBECOM WORKSHOPS (GC WKSHPS): . Paper presented at IEEE-Communications-Society Global Communications Conference (IEEE GLOBECOM), DEC 04-08, 2016, Washington, DC. New York: IEEE
Open this publication in new window or tab >>5G on Board: How Many Antennas Do We Need on Connected Cars?
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2016 (English)In: 2016 IEEE GLOBECOM WORKSHOPS (GC WKSHPS), New York: IEEE, 2016Conference paper, Published paper (Refereed)
Abstract [en]

Mobile networks will support increasing numbers of connected vehicles. Successive generations of mobile networks have reduced the cost of data rate, in terms of spectrum usage and power consumption at the base station, by increasingly exploiting the concept of channel state information at the transmitter. Unfortunately, beyond a limiting velocity (which depends on the carrier frequency), networks are no longer cost efficient, since such information is not usable. Recently, channel prediction techniques requiring several antennas on the car roof have been introduced to solve this problem. In this paper, for the first time, we determine the most cost efficient configurations, in terms of numbers of antennas on the car roof and carrier frequency, in various scenarios (highway and dense urban). Our studies show that with a simple prediction technique based on predictor antennas, the network can use twice less spectrum and around 20 dB less power, for cars with 3 antennas on their tops than for cars with the same number of antennas and not using prediction.

Place, publisher, year, edition, pages
New York: IEEE, 2016
Series
IEEE Globecom Workshops, ISSN 2166-0069
Keywords
5G, connected cars, predictor antenna, MIMO
National Category
Telecommunications
Identifiers
urn:nbn:se:uu:diva-332913 (URN)10.1109/GLOCOMW.2016.7848799 (DOI)000401921400002 ()978-1-5090-2482-7 (ISBN)
Conference
IEEE-Communications-Society Global Communications Conference (IEEE GLOBECOM), DEC 04-08, 2016, Washington, DC
Available from: 2017-11-03 Created: 2017-11-03 Last updated: 2018-11-08Bibliographically approved
Phan-Huy, D.-T., Svensson, T., Sternad, M., Zirwas, W., Villeforceix, B., Karim, F. & Sayrac, B. (2015). Connected vehicles that use channel prediction will fully take advantage of 5G. In: : . Paper presented at 22nd ITS World Congress, Bordeaux, Frankrike, 5-9 Oktober.
Open this publication in new window or tab >>Connected vehicles that use channel prediction will fully take advantage of 5G
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2015 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Research subject
Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-267315 (URN)
Conference
22nd ITS World Congress, Bordeaux, Frankrike, 5-9 Oktober
Available from: 2015-11-20 Created: 2015-11-20 Last updated: 2015-11-20
Brännmark, L.-J. & Sternad, M. (2015). Controlling the impulse responses and the spatial variability in digital loudspeaker-room correction. In: : . Paper presented at 2015 International Symposium on ELectroAcoustic Technologies (ISEAT), Shenzhen, Kina, november.
Open this publication in new window or tab >>Controlling the impulse responses and the spatial variability in digital loudspeaker-room correction
2015 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Research subject
Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-267314 (URN)
Conference
2015 International Symposium on ELectroAcoustic Technologies (ISEAT), Shenzhen, Kina, november
Available from: 2015-11-20 Created: 2015-11-20 Last updated: 2015-11-20
Phan-Huy, D.-T., Sternad, M. & Svensson, T. (2015). Making 5G Adaptive Antennas Work for Very Fast Moving Vehicles. IEEE Intelligent Transportation Systems Magazine, 7(2), 71-84
Open this publication in new window or tab >>Making 5G Adaptive Antennas Work for Very Fast Moving Vehicles
2015 (English)In: IEEE Intelligent Transportation Systems Magazine, ISSN 1939-1390, Vol. 7, no 2, p. 71-84Article in journal (Refereed) Published
Abstract [en]

Wireless systems increasingly rely on the accurate knowledge at the transmitter side of the transmitter-to-receiver propagation channel, to optimize the transmission adaptively. Some candidate techniques for 5th generation networks need the channel knowledge for tens of antennas to perform adaptive beamforming from the base station towards the mobile terminal. These techniques reduce the radiated power and the energy consumption of the base station. Unfortunately, they fail to deliver the targeted quality of service to fast moving terminals such as connected vehicles. Indeed, due to the movement of the vehicle during the delay between channel estimation and data transmission, the channel estimate is outdated. In this paper, we propose three new schemes that exploit the "Predictor Antenna" concept. This recent concept is based on the observation that the position occupied by one antenna at the front of the vehicle, will later on be occupied by another antenna at the back. Estimating the channel of the "front" antenna can therefore later help beamforming towards the "back" antenna. Simulations show that our proposed schemes make adaptive beamforming work for vehicles moving at speeds up to 300 km/h.

National Category
Transport Systems and Logistics Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-252960 (URN)10.1109/MITS.2015.2408151 (DOI)000353572400009 ()
Available from: 2015-05-20 Created: 2015-05-18 Last updated: 2016-01-06Bibliographically approved
Barkefors, A. & Sternad, M. (2014). Adapting an MSE controller for active noise control to nonstationary noise statistics. In: : . Paper presented at 43rd International Congress on Noise Control Engineering, Melbourne, Australien, November 16-19.
Open this publication in new window or tab >>Adapting an MSE controller for active noise control to nonstationary noise statistics
2014 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Research subject
Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-235002 (URN)
Conference
43rd International Congress on Noise Control Engineering, Melbourne, Australien, November 16-19
Available from: 2014-10-28 Created: 2014-10-28 Last updated: 2014-10-28
Jamaly, N., Apelfröjd, R., Martinez, A. B., Grieger, M., Svensson, T., Sternad, M. & Fettweis, G. (2014). Analysis and Measurement of Multiple Antenna Systems for Fading Channel Prediction in Moving Relays. In: 2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP): . Paper presented at The 8th European Conference on Antennas and Propagation (EuCAP), to be held at the World Forum in The Hague, The Netherlands, on 6-11 April 2014. (pp. 2015-2019).
Open this publication in new window or tab >>Analysis and Measurement of Multiple Antenna Systems for Fading Channel Prediction in Moving Relays
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2014 (English)In: 2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 2014, p. 2015-2019Conference paper, Published paper (Other academic)
Abstract [en]

The performance of wireless data transmission to mobile vehicles is improved if channel state information is available at the transmitter but movement of vehicles causes outdating of channel estimates. The concept of a predictor antenna has recently been proposed, where an antenna is placed in front of other antennas on the roof of the vehicle to sense the radio environment in advance. This can comparatively provide an order-of-magnitude improvement in channel prediction performance. A potential problem with this idea is that closely placed antennas will experience mutual electromagnetic couplings. These may reduce the efficiency of the predictor antenna concept if they are not taken into account. In this paper, we discuss about how to treat the forgoing issue and eventually evaluate a promising candidate on measured channels. We argue that only open-circuit voltage method would be realistic for the present application. The usefulness of the proposed decoupling method is demonstrated on field measurements obtained in downtown Dresden, Germany. We also partly address the sensitivity of the open-circuit decoupling method to the accuracy of the utilized network parameters.

Series
Proceedings of the European Conference on Antennas and Propagation, ISSN 2164-3342
Keywords
Multi-element antennas; channel state prediction; moving relays; multipath measurement
National Category
Engineering and Technology
Research subject
Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-224256 (URN)978-88-907018-4-9 (ISBN)
Conference
The 8th European Conference on Antennas and Propagation (EuCAP), to be held at the World Forum in The Hague, The Netherlands, on 6-11 April 2014.
Note

This paper has been presented as a poster on: the 8th European Conference on Antennas and Propagation (EuCAP), in The Hague, The Netherlands, on 6-11 April 2014, and will appear in the proceedings

Available from: 2014-05-08 Created: 2014-05-07 Last updated: 2015-11-06Bibliographically approved
Barkefors, A., Sternad, M. & Brännmark, L.-J. (2014). Design and Analysis of Linear Quadratic Gaussian Feedforward Controllers for Active Noise Control. IEEE Transactions on Audio, Speech, and Language Processing, 22(12), 1777-1791
Open this publication in new window or tab >>Design and Analysis of Linear Quadratic Gaussian Feedforward Controllers for Active Noise Control
2014 (English)In: IEEE Transactions on Audio, Speech, and Language Processing, ISSN 1558-7916, E-ISSN 1558-7924, Vol. 22, no 12, p. 1777-1791Article in journal (Refereed) Published
Abstract [en]

A method for sound field control applied to active noise control is presented and evaluated. The method uses Linear Quadratic Gaussian (LQG) feedforward control to find a Minimal Mean Square Error (MMSE)-optimal linear sound field controller under a causality constraint. It is obtained by solving a polynomial matrix spectral factorization and a linear (Diophantine) polynomial matrix equation. An important component in the design is the control signal penalty term of the criterion. Its use and influence is here discussed and evaluated using measured room impulse responses. The results indicate that the use of a relatively simple, frequency-weighted penalty on individual control signals provides most of the benefits obtainable by the considered more advanced alternative. We also introduce and illustrate several tools for performance analysis. An analytical expression for the attainable performance clearly reveals the performance loss generated by having to use a causal controller instead of the ideal noncausal controller. This loss is largest at low frequencies. Furthermore, we introduce a measure of the reproducibility of the target noise sound field with given control loudspeaker setups and room transfer functions. It describes how well a controller that uses an input subspace of dimension equal to the effective rank of the system is able to reproduce a target sound field. This performance measure can e.g. be used to support the selection of good combinations of placements of control loudspeakers.

National Category
Control Engineering
Identifiers
urn:nbn:se:uu:diva-223813 (URN)10.1109/TASLP.2014.2349856 (DOI)000341627500008 ()
Funder
Swedish Research Council, 2009-5527
Available from: 2014-04-27 Created: 2014-04-27 Last updated: 2017-12-05Bibliographically approved
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