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Van Chien, T., Björnson, E., Larsson, E. G. & Le, T. A. (2018). Distributed Power Control in Downlink CellularMassive MIMO Systems. In: : . Paper presented at IEEE 22nd International ITG Workshop on Smart Antennas (WSA2018) (pp. 1-7). VDE Verlag GmbH
Open this publication in new window or tab >>Distributed Power Control in Downlink CellularMassive MIMO Systems
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This paper compares centralized and distributed methods to solve the power minimization problem with quality-of-service (QoS) constraints in the downlink (DL) of multi-cell Massive multiple-input multiple-output (MIMO) systems. In particular, we study the computational complexity, number of parameters that need to be exchanged between base stations (BSs), and the convergence of iterative implementations. Although a distributed implementation based on dual decomposition (which only requires statistical channel knowledge at each BS) typically converges to the global optimum after a few iterations, many parameters need to be exchanged to reach convergence.

Place, publisher, year, edition, pages
VDE Verlag GmbH, 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-148936 (URN)978-3-8007-4541-8 (ISBN)
Conference
IEEE 22nd International ITG Workshop on Smart Antennas (WSA2018)
Projects
5GwirelessELLIITCENIIT
Available from: 2018-06-22 Created: 2018-06-22 Last updated: 2018-06-22
Do, T. T., Björnson, E., Larsson, E. G. & Mohammad Razavizadeh, S. (2018). Jamming-Resistant Receivers for the Massive MIMO Uplink. Paper presented at IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP). IEEE Transactions on Information Forensics and Security, 13(1), 210-223
Open this publication in new window or tab >>Jamming-Resistant Receivers for the Massive MIMO Uplink
2018 (English)In: IEEE Transactions on Information Forensics and Security, ISSN 1556-6013, E-ISSN 1556-6021, Vol. 13, no 1, p. 210-223Article in journal (Refereed) Published
Abstract [en]

We design a jamming-resistant receiver scheme to enhance the robustness of a massive MIMO uplink system against jamming. We assume that a jammer attacks the system both in the pilot and data transmission phases. The key feature of the proposed scheme is that, in the pilot phase, the base station estimates not only the legitimate channel, but also the jamming channel by exploiting a purposely unused pilot sequence. The jamming channel estimate is used to construct linear receiver filters that reject the impact of the jamming signal. The performance of the proposed scheme is analytically evaluated using the asymptotic properties of massive MIMO. The best regularized zero-forcing receiver and the optimal power allocations for the legitimate system and the jammer are also studied. Numerical results are provided to verify our analysis and show that the proposed scheme greatly improves the achievable rates, as compared with conventional receivers. Interestingly, the proposed scheme works particularly well under strong jamming attacks, since the improved estimate of the jamming channel outweighs the extra jamming power.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Massive MIMO; jamming attack; receiver filter; optimal power allocation
National Category
Signal Processing
Identifiers
urn:nbn:se:liu:diva-143986 (URN)10.1109/TIFS.2017.2746007 (DOI)000417725500016 ()2-s2.0-85028560448 (Scopus ID)
Conference
IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
Note

Funding Agencies|ELLIIT; CENIIT

Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-12Bibliographically approved
Van Chien, T., Björnson, E. & Larsson, E. G. (2018). Joint Pilot Design and Uplink Power Allocation in Multi-Cell Massive MIMO Systems. IEEE Transactions on Wireless Communications, 17(3), 2000-2015
Open this publication in new window or tab >>Joint Pilot Design and Uplink Power Allocation in Multi-Cell Massive MIMO Systems
2018 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 3, p. 2000-2015Article in journal (Refereed) Published
Abstract [en]

This paper considers pilot design to mitigate pilot contamination and provide good service for everyone in multi-cell Massive multiple input multiple output (MIMO) systems. Instead of modeling the pilot design as a combinatorial assignment problem, as in prior works, we express the pilot signals using a pilot basis and treat the associated power coefficients as continuous optimization variables. We compute a lower bound on the uplink capacity for Rayleigh fading channels with maximum ratio detection that applies with arbitrary pilot signals. We further formulate the max-min fairness problem under power budget constraints, with the pilot signals and data powers as optimization variables. Because this optimization problem is non-deterministic polynomial-time hard due to signomial constraints, we then propose an algorithm to obtain a local optimum with polynomial complexity. Our framework serves as a benchmark for pilot design in scenarios with either ideal or non-ideal hardware. Numerical results manifest that the proposed optimization algorithms are close to the optimal solution obtained by exhaustive search for different pilot assignments and the new pilot structure and optimization bring large gains over the state-of-the-art suboptimal pilot design.

Place, publisher, year, edition, pages
IEEE Communications Society, 2018
Keywords
Massive MIMO, Pilot Design, Signomial Programming, Geometric Programming, Hardware Impairments.
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-145713 (URN)10.1109/TWC.2017.2787702 (DOI)000427226500042 ()2-s2.0-85040035548 (Scopus ID)
Projects
CENIIT
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsEU, Horizon 2020, 641985
Note

Funding agencies:This work was supported in part by the European Union's Horizon 2020 Research and Innovation Programme under Grant 641985 (5Gwireless), in part by ELLIIT, and in part by CENIIT. This paper was presented at the IEEE ICC 2017. The associate editor coordinating the review of this paper and approving it for publication was T. Lok.

Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-04-12Bibliographically approved
Chandhar, P., Danev, D. & Larsson, E. G. (2018). Massive MIMO for Communications With Drone Swarms. IEEE Transactions on Wireless Communications, 17(3), 1604-1629
Open this publication in new window or tab >>Massive MIMO for Communications With Drone Swarms
2018 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 3, p. 1604-1629Article in journal (Refereed) Published
Abstract [en]

We illustrate the potential of Massive MIMO for communication with unmanned aerial vehicles (UAVs). We consider a scenario, where multiple single-antenna UAVs simultaneously communicate with a ground station (GS) equipped with a large number of antennas. Specifically, we discuss the achievable uplink (UAV to GS) capacity performance in the case of line-of-sight conditions. We develop a realistic geometric model, which incorporates an arbitrary orientation, of the GS and UAV antenna elements to characterize the polarization mismatch loss, which occurs due to the movement and orientation of the UAVs. A closed-form expression for a lower bound on the ergodic rate for a maximum-ratio combining receiver with estimated channel state information is derived. The optimal antenna spacing that maximizes the ergodic rate achieved by an UAV is also determined for uniform linear and rectangular arrays. It is shown that when the UAVs are spherically uniformly distributed around the GS, the ergodic rate per UAV is maximized for an antenna spacing equal to an integer multiple of one-half wavelength.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Unmanned aerial vehicles; Massive MIMO; ergodic capacity
National Category
Telecommunications
Identifiers
urn:nbn:se:liu:diva-147124 (URN)10.1109/TWC.2017.2782690 (DOI)000427226500015 ()
Note

Funding Agencies|Swedish Research Council (VR); ELLIIT

Available from: 2018-04-20 Created: 2018-04-20 Last updated: 2018-06-13
Interdonato, G., Frenger, P. & Larsson, E. G. (2018). Utility-based Downlink Pilot Assignment in Cell-Free Massive MIMO. In: : . Paper presented at The 22nd International ITG Workshop on Smart Antennas (WSA 2018), March 14-16, Bochum, Germany.
Open this publication in new window or tab >>Utility-based Downlink Pilot Assignment in Cell-Free Massive MIMO
2018 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

We propose a strategy for orthogonal downlink pilot assignment in cell-free massive MIMO (multiple-input multiple-output) that exploits knowledge of the channel state information, the channel hardening degree at each user, and the mobility conditions for the users. These elements, properly combined together, are used to define a user pilot utility metric, which measures the user's real need of a downlink pilot for efficient data decoding. The proposed strategy consists in assigning orthogonal downlink pilots only to the users having a pilot utility metric exceeding a predetermined threshold. Instead, users that are not assigned with an orthogonal downlink pilot decode the data by using the statistical channel state information. The utility-based approach guarantees higher downlink net sum throughput, better support both for high-speed users and shorter coherent intervals than prior art approaches.

National Category
Communication Systems Telecommunications Signal Processing
Identifiers
urn:nbn:se:liu:diva-146247 (URN)
Conference
The 22nd International ITG Workshop on Smart Antennas (WSA 2018), March 14-16, Bochum, Germany
Available from: 2018-04-04 Created: 2018-04-04 Last updated: 2018-04-23
Ngo, H. Q., Tran, L.-N., Duong, T. Q., Matthaiou, M. & Larsson, E. G. (2017). Energy Efficiency Optimization for Cell-Free Massive MIMO. In: 2017 IEEE 18TH INTERNATIONAL WORKSHOP ON SIGNAL PROCESSING ADVANCES IN WIRELESS COMMUNICATIONS (SPAWC): . Paper presented at 18th IEEE International Workshop on Signal Processing Advances for Wireless Communications (SPAWC), Sapporo, Japan, 3-76 July 2017.
Open this publication in new window or tab >>Energy Efficiency Optimization for Cell-Free Massive MIMO
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2017 (English)In: 2017 IEEE 18TH INTERNATIONAL WORKSHOP ON SIGNAL PROCESSING ADVANCES IN WIRELESS COMMUNICATIONS (SPAWC), 2017Conference paper, Published paper (Refereed)
Abstract [en]

This paper considers a time-division duplex cell-free massive multiple-input multiple-output downlink with imperfect channel station information and conjugate beamforming scheme. The total energy efficiency is investigated taking into account the hardware power consumption and the backhaul power consumption. We propose an optimal power allocation algorithm which aims to maximize the total energy efficiency, under a per-access point power constraint and a per-user spectral efficiency constraint. This optimization problem can be approximately solved via a sequence of second-order cone programs. Compared with the case of without power control, our proposed power allocation scheme can double the total energy efficiency. Furthermore, we show that, when the number of access points is large, the backhaul power consumption affects significantly the total energy efficiency.

Series
IEEE International Workshop on Signal Processing Advances in Wireless Communications, ISSN 2325-3789
Keywords
Cell-free massive MIMO, conjugate beamforming, energy efficiency, massive MIMO, network MIMO
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-147281 (URN)10.1109/SPAWC.2017.8227722 (DOI)000427595900086 ()978-1-5090-3009-5 (ISBN)978-1-5090-3010-1 (ISBN)
Conference
18th IEEE International Workshop on Signal Processing Advances for Wireless Communications (SPAWC), Sapporo, Japan, 3-76 July 2017
Available from: 2018-04-12 Created: 2018-04-12 Last updated: 2018-04-12
Do, T. T., Björnson, E. & Larsson, E. G. (2017). JAMMING RESISTANT RECEIVERS FOR MASSIVE MIMO. In: 2017 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP): . Paper presented at The 42nd IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP2017), New Orleans, USA, March 5-9, 2017 (pp. 3619-3623). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>JAMMING RESISTANT RECEIVERS FOR MASSIVE MIMO
2017 (English)In: 2017 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 3619-3623Conference paper, Published paper (Refereed)
Abstract [en]

We design jamming resistant receivers to enhance the robustness of a massive MIMO uplink channel against jamming. In the pilot phase, we estimate not only the desired channel, but also the jamming channel by exploiting purposely unused pilot sequences. The jamming channel estimate is used to construct the linear receive filter to reduce impact that jamming has on the achievable rates. The performance of the proposed scheme is analytically and numerically evaluated. These results show that the proposed scheme greatly improves the rates, as compared to conventional receivers. Moreover, the proposed schemes still work well with stronger jamming power.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Series
International Conference on Acoustics Speech and Signal Processing ICASSP, ISSN 1520-6149
Keywords
Massive MIMO; jamming attack; receive filter
National Category
Signal Processing
Identifiers
urn:nbn:se:liu:diva-144281 (URN)10.1109/ICASSP.2017.7952831 (DOI)000414286203156 ()2-s2.0-85023753985 (Scopus ID)978-1-5090-4117-6 (ISBN)
Conference
The 42nd IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP2017), New Orleans, USA, March 5-9, 2017
Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-01-19Bibliographically approved
de Carvalho, E., Björnson, E., Sorensen, J. H., Larsson, E. G. & Popovski, P. (2017). Random Pilot and Data Access in Massive MIMO for Machine-Type Communications. Paper presented at 41st IEEE International Conference on Acoustics, Speech, and Signal Processing. IEEE Transactions on Wireless Communications, 16(12), 7703-7717
Open this publication in new window or tab >>Random Pilot and Data Access in Massive MIMO for Machine-Type Communications
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2017 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 16, no 12, p. 7703-7717Article in journal (Refereed) Published
Abstract [en]

A massive MIMO system, represented by a base station with hundreds of antennas, is capable of spatially multiplexing many devices and thus naturally suited to serve dense crowds of wireless devices in emerging applications, such as machine-type communications. Crowd scenarios pose new challenges in the pilot-based acquisition of channel state information and call for pilot access protocols that match the intermittent pattern of device activity. A joint pilot assignment and data transmission protocol based on random access is proposed in this paper for the uplink of a massive MIMO system. The protocol relies on the averaging across multiple transmission slots of the pilot collision events that result from the random access process. We derive new uplink sum rate expressions that take pilot collisions, intermittent device activity, and interference into account. Simplified bounds are obtained and used to optimize the device activation probability and pilot length. A performance analysis indicates how performance scales as a function of the number of antennas and the transmission slot duration.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
Machine-type communications; massive MIMO; pilot collisions; pilot contamination; random access
National Category
Telecommunications
Identifiers
urn:nbn:se:liu:diva-144150 (URN)10.1109/TWC.2017.2748106 (DOI)000418184400002 ()2-s2.0-85030757777 (Scopus ID)
Conference
41st IEEE International Conference on Acoustics, Speech, and Signal Processing
Note

Funding Agencies|Danish Council for Independent Research [DFF133500273]; Danish National Advanced Technology Foundation via the VIRTUOSO Project; Horizon Project FANTASTIC-5G [ICT-671660]; EU FP7 Project MAMMOET [ICT-619086]; ELLIIT; CENIIT

Available from: 2018-01-09 Created: 2018-01-09 Last updated: 2018-01-17Bibliographically approved
Van Chien, T., Björnson, E. & Larsson, E. G. (2016). Downlink Power Control for Massive MIMO Cellular Systems with Optimal User Association. In: IEEE International Conference on Communications, Malaysia, May 23-27, 2016: proceedings. Paper presented at IEEE International Conference on Communications, Malaysia, May 23-27. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Downlink Power Control for Massive MIMO Cellular Systems with Optimal User Association
2016 (English)In: IEEE International Conference on Communications, Malaysia, May 23-27, 2016: proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper, Published paper (Refereed)
Abstract [en]

This paper aims to minimize the total transmit power consumption for Massive MIMO (multiple-input multiple-output) downlink cellular systems when each user is served by the optimized subset of the base stations (BSs). We derive a lower bound on the ergodic spectral efficiency (SE) for Rayleigh fading channels and maximum ratio transmission (MRT) when the BSs cooperate using non-coherent joint transmission. We solve the joint user association and downlink transmit power minimization problem optimally under fixed SE constraints. Furthermore, we solve a max-min fairness problem with user specific weights that maximizes the worst SE among the users. The optimal BS-user association rule is derived, which is different from maximum signal-to-noise-ratio (max-SNR) association. Simulation results manifest that the proposed methods can provide good SE for the users using less transmit power than in small-scale systems and that the optimal user association can effectively balance the load between BSs when needed.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Series
IEEE International Conference on Communications, ISSN 1550-3607
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-130168 (URN)10.1109/ICC.2016.7510950 (DOI)000390993201146 ()978-1-5090-0448-5 (ISBN)
Conference
IEEE International Conference on Communications, Malaysia, May 23-27
Available from: 2016-07-13 Created: 2016-07-13 Last updated: 2017-01-29Bibliographically approved
Savic, V. & Larsson, E. G. (2016). Experimental Study of Indoor Tracking Using UWB Measurements and Particle Filtering. In: 2016 IEEE 17TH INTERNATIONAL WORKSHOP ON SIGNAL PROCESSING ADVANCES IN WIRELESS COMMUNICATIONS (SPAWC): . Paper presented at 17th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC 2016), 3-6 July 2016, Edinburgh, UK. IEEE
Open this publication in new window or tab >>Experimental Study of Indoor Tracking Using UWB Measurements and Particle Filtering
2016 (English)In: 2016 IEEE 17TH INTERNATIONAL WORKSHOP ON SIGNAL PROCESSING ADVANCES IN WIRELESS COMMUNICATIONS (SPAWC), IEEE , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Target tracking with ultra-wideband (UWB) signals in indoor environments is a challenging problem due to the presence of multipath and non-line-of-sight conditions (NLOS). A solution to this problem is to use particle filtering (PF), which is able to handle both nonlinear models and non-Gaussian uncertainties that typically appear in the presence of NLOS. In this paper, we compare four different PF variants, that differ in terms of how  NLOS measurements are handled. According to our experimental results, based on the measurements from a basement tunnel,    multiple features from the UWB impulse response should be used, and  the ranging likelihood function should make use of both LOS and NLOS measurements. Standard time-of-arrival (TOA) based methods, even with NLOS rejection, are not good enough. Instead we advocate TOA-based algorithms that can actively mitigate errors due to NLOS.

Place, publisher, year, edition, pages
IEEE, 2016
Series
IEEE International Workshop on Signal Processing Advances in Wireless Communications, ISSN 2325-3789
Keywords
target tracking, ultra-wideband, particle filtering, machine learning, time of arrival
National Category
Communication Systems Signal Processing
Identifiers
urn:nbn:se:liu:diva-128263 (URN)10.1109/SPAWC.2016.7536853 (DOI)000382942700128 ()
Conference
17th IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC 2016), 3-6 July 2016, Edinburgh, UK
Projects
COOPLOC
Funder
Swedish Foundation for Strategic Research ELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Available from: 2016-05-24 Created: 2016-05-24 Last updated: 2016-11-21
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7599-4367

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