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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, 210-223 p.Article 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
Keyword
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
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, 7703-7717 p.Article 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
Keyword
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
Keyword
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
Khan Mohammed, S. & Larsson, E. G. (2016). Improving the Performance of the Zero-Forcing Multiuser MISO Downlink Precoder Through User Grouping. IEEE Transactions on Wireless Communications, 15(2), 811-826.
Open this publication in new window or tab >>Improving the Performance of the Zero-Forcing Multiuser MISO Downlink Precoder Through User Grouping
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 2, 811-826 p.Article in journal (Refereed) Published
Abstract [en]

We consider the multiple input single output (MISO) Gaussian broadcast channel with N-t antennas at the base station (BS) and N-u single-antenna users in the downlink. We propose a novel user grouping precoder which improves the sum rate performance of the zero-forcing (ZF) precoder specially when the channel is ill-conditioned. The proposed precoder partitions all the users into small groups of equal size. Downlink beamforming is then done in such a way that, at each users receiver, the interference from the signal intended for users not in its group is nulled out. Intragroup interference still remains, and is cancelled through successive interference presubtraction at the BS using dirty paper coding (DPC). The proposed user grouping method is different from user selection, since it is a method for precoding of information to the selected (scheduled) users, and not for selecting which users are to be scheduled. The proposed precoder is a generalization of two special cases, one where each group has only one user (ZF precoder) and another where all users are in a single group (ZF-DP precoder). A larger group size helps improve the sum rate performance but at the cost of greater complexity. The proposed generalization, therefore, allows for tradeoff between performance and complexity.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016
Keyword
MIMO broadcast channel; precoding; low complexity; user grouping; dirty paper coding; zero-forcing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-126260 (URN)10.1109/TWC.2015.2478878 (DOI)000370949600001 ()
Note

Funding Agencies|EMR funding from the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Government of India; Swedish Research Council; ELLIIT

Available from: 2016-03-21 Created: 2016-03-21 Last updated: 2017-11-30
Larsson, E. G. & Vincent Poor, H. (2016). Joint Beamforming and Broadcasting in Massive MIMO. IEEE Transactions on Wireless Communications, 15(4), 3058-3070.
Open this publication in new window or tab >>Joint Beamforming and Broadcasting in Massive MIMO
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 4, 3058-3070 p.Article in journal (Refereed) Published
Abstract [en]

The downlink of a massive MIMO system is considered for the case in which the base station must concurrently serve two categories of terminals: one group to which imperfect instantaneous channel state information (CSI) is available and one group to which no CSI is available. Motivating applications include broadcasting of public channels and control information in wireless networks. A new technique is developed and analyzed: joint beamforming and broadcasting (JBB), by which the base station beamforms to the group of terminals to which CSI is available, and broadcasts to the other group of terminals, to which no CSI is available. The broadcast information does not interfere with the beamforming as it is placed in the nullspace of the channel matrix collectively seen by the terminals targeted by the beamforming. JBB is compared to orthogonal access (OA) by which the base station partitions the time-frequency resources into two disjunct parts, one for each group of terminals. It is shown that JBB can substantially outperform OA in terms of required total radiated power for given rate targets.

Place, publisher, year, edition, pages
IEEE Press, 2016
Keyword
Broadcasting; beamforming; control signaling; massive MIMO; public channels
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-127782 (URN)10.1109/TWC.2016.2515598 (DOI)000374240500047 ()
Note

Funding Agencies|Swedish Research Council (VR); ELLIIT; U.S. National Science Foundation [CNS-1456793, ECCS-1343210]

Available from: 2016-05-12 Created: 2016-05-12 Last updated: 2017-11-30
Van Chien, T., Björnson, E. & Larsson, E. G. (2016). Joint Power Allocation and User Association Optimization for Massive MIMO Systems. IEEE Transactions on Wireless Communications, 15(9), 6384-6399.
Open this publication in new window or tab >>Joint Power Allocation and User Association Optimization for Massive MIMO Systems
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 9, 6384-6399 p.Article in journal (Refereed) Published
Abstract [en]

This paper investigates the joint power allocationand user association problem in multi-cell Massive MIMO(multiple-input multiple-output) downlink (DL) systems. Thetarget is to minimize the total transmit power consumptionwhen each user is served by an optimized subset of the basestations (BSs), using non-coherent joint transmission. We firstderive a lower bound on the ergodic spectral efficiency (SE),which is applicable for any channel distribution and precodingscheme. Closed-form expressions are obtained for Rayleigh fadingchannels with either maximum ratio transmission (MRT) or zeroforcing (ZF) precoding. From these bounds, we further formulatethe DL power minimization problems with fixed SE constraintsfor the users. These problems are proved to be solvable aslinear programs, giving the optimal power allocation and BS-user association with low complexity. Furthermore, we formulatea max-min fairness problem which maximizes the worst SEamong the users, and we show that it can be solved as aquasi-linear program. Simulations manifest that the proposedmethods provide good SE for the users using less transmit powerthan in small-scale systems and the optimal user associationcan effectively balance the load between BSs when needed.Even though our framework allows the joint transmission frommultiple BSs, there is an overwhelming probability that only oneBS is associated with each user at the optimal solution.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Keyword
Massive MIMO, user association, power allocation, load balancing, linear program
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-131129 (URN)10.1109/TWC.2016.2583436 (DOI)000384241400040 ()
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Available from: 2016-09-11 Created: 2016-09-11 Last updated: 2018-01-11Bibliographically approved
Savic, V., Larsson, E. G., Ferrer-Coll, J. & Stenumgaard, P. (2016). Kernel Methods for Accurate UWB-Based Ranging with Reduced Complexity. IEEE Transactions on Wireless Communications, 15(3), 1783-1793.
Open this publication in new window or tab >>Kernel Methods for Accurate UWB-Based Ranging with Reduced Complexity
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 3, 1783-1793 p.Article in journal (Refereed) Published
Abstract [en]

Accurate and robust positioning in multipath environments can enable many applications, such as search-and-rescue and asset tracking. For this problem, ultra-wideband (UWB) technology can provide the most accurate range estimates, which are required for range-based positioning. However, UWB still faces a problem with non-line-of-sight (NLOS) measurements, in which the range estimates based on time-of-arrival (TOA) will typically be positively biased. There are many techniques that address this problem, mainly based on NLOS identification and NLOS error mitigation algorithms. However, these techniques do not exploit all available information in the UWB channel impulse response. Kernel-based machine learning methods, such as Gaussian Process Regression (GPR), are able to make use of all information, but they may be too complex in their original form. In this paper, we propose novel ranging methods based on kernel principal component analysis (kPCA), in which the selected channel parameters are projected onto a nonlinear orthogonal high-dimensional space, and a subset of these projections is then used as an input for ranging. We evaluate the proposed methods using real UWB measurements obtained in a basement tunnel, and found that one of the proposed methods is able to outperform state-of-the-art, even if little training samples are available.

Place, publisher, year, edition, pages
IEEE Computer Society, 2016
Keyword
ranging, positioning, ultra-wideband, time-of-arrival, kernel principal component analysis, Gaussian process regression, machine learning
National Category
Communication Systems Signal Processing
Identifiers
urn:nbn:se:liu:diva-122424 (URN)10.1109/TWC.2015.2496584 (DOI)000372627500013 ()
Projects
COOPLOC
Funder
Swedish Foundation for Strategic Research
Note

Funding agencies: project Cooperative Localization (CoopLoc) - Swedish Foundation for Strategic Research (SSF); Security Link

Available from: 2015-11-02 Created: 2015-11-02 Last updated: 2017-12-01
Chandhar, P., Danev, D. & Larsson, E. G. (2016). Massive MIMO as Enabler for Communications with Drone Swarms. In: 2016 INTERNATIONAL CONFERENCE ON UNMANNED AIRCRAFT SYSTEMS (ICUAS): . Paper presented at ICUAS'16 The 2016 International Conference on Unmanned Aircraft Systems, June 7 - 10, Key Bridge Marriott, Arlington, VA, USA (pp. 347-354). IEEE.
Open this publication in new window or tab >>Massive MIMO as Enabler for Communications with Drone Swarms
2016 (English)In: 2016 INTERNATIONAL CONFERENCE ON UNMANNED AIRCRAFT SYSTEMS (ICUAS), IEEE , 2016, 347-354 p.Conference paper, Published paper (Refereed)
Abstract [en]

Massive multiple-input multiple-output (MIMO) is an emerging technology for mobile communications, where a large number of antennas are employed at the base station to simultaneously serve multiple single-antenna terminals with very high capacity. In this paper, we study the potentials and challenges of utilizing massive MIMO for unmanned aerial vehicles (UAVs) communication. We consider a scenario where multiple single-antenna UAVs simultaneously communicate with a ground station (GS) equipped with a large number of antennas. Speci[1]cally, we discuss the achievable uplink (UAV to GS) capacity performance in the case of line-of-sight (LoS) conditions. We also study the type of antenna polarization that should be used in order to maintain a reliable communication link between the GS and the UAVs. The results obtained using a realistic geometric model show that massive MIMO is a potential enabler for high-capacity UAV network

Place, publisher, year, edition, pages
IEEE, 2016
Series
International Conference on Unmanned Aircraft Systems, ISSN 2373-6720
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-129713 (URN)10.1109/ICUAS.2016.7502655 (DOI)000390883100043 ()978-1-4673-9333-1 (ISBN)
Conference
ICUAS'16 The 2016 International Conference on Unmanned Aircraft Systems, June 7 - 10, Key Bridge Marriott, Arlington, VA, USA
Available from: 2016-06-24 Created: 2016-06-24 Last updated: 2017-01-29Bibliographically approved
Björnson, E., Larsson, E. G. & Debbah, M. (2016). Massive MIMO for Maximal Spectral Efficiency: How Many Users and Pilots Should Be Allocated?. IEEE Transactions on Wireless Communications, 15(2), 1293-1308.
Open this publication in new window or tab >>Massive MIMO for Maximal Spectral Efficiency: How Many Users and Pilots Should Be Allocated?
2016 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 15, no 2, 1293-1308 p.Article in journal (Refereed) Published
Abstract [en]

Massive MIMO is a promising technique for increasing the spectral efficiency (SE) of cellular networks, by deploying antenna arrays with hundreds or thousands of active elements at the base stations and performing coherent transceiver processing. A common rule-of-thumb is that these systems should have an order of magnitude more antennas M than scheduled users K because the users channels are likely to be near-orthogonal when M/K > 10. However, it has not been proved that this rule-of-thumb actually maximizes the SE. In this paper, we analyze how the optimal number of scheduled users K-star depends on M and other system parameters. To this end, new SE expressions are derived to enable efficient system-level analysis with power control, arbitrary pilot reuse, and random user locations. The value of K-star in the large-M regime is derived in closed form, while simulations are used to show what happens at finite M, in different interference scenarios, with different pilot reuse factors, and for different processing schemes. Up to half the coherence block should be dedicated to pilots and the optimal M/K is less than 10 in many cases of practical relevance. Interestingly, K-star depends strongly on the processing scheme and hence it is unfair to compare different schemes using the same K.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016
Keyword
Coordinated multipoint; massive MIMO; multi-cell; pilot contamination; spectral efficiency; user scheduling
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-126261 (URN)10.1109/TWC.2015.2488634 (DOI)000370949600036 ()
Note

Funding Agencies|EU [ICT-619086]; ELLIIT; Swedish Research Council (VR); ERC [305123 MORE]

Available from: 2016-03-21 Created: 2016-03-21 Last updated: 2017-11-30
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7599-4367

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