PDF Icon Wireless Channel Modeling Perspectives for Ultra-Reliable Communications

Wireless Channel Modeling Perspectives for Ultra-Reliable Communications

Eggers, P. C. F., Angjelichinoski, M. & Popovski, P., 12 Feb 2019, (Accepted/In press) In : IEEE Transactions on Wireless Communications.

Research output: Contribution to journalJournal articleResearchpeer-review

Ultra-Reliable Communication (URC) is one of the distinctive features of the upcoming 5G wireless communication, going down to packet error rates (PER) of
10^-9. In this paper we analyze the tail of the Cumulative Distribution Function (CDF) of block fading channels in the regime of extremely rare events, i.e., the ultra-reliable (UR) regime of operation. Our main contribution consists of providing a unified framework for statistical description of wide range of practically important wireless channel models in the UR regime of operation. Specifically, we show that the wireless channel behavior
in this regime can be approximated by a simple power law
expression, whose exponent and offset depend on the actual channel model. The unification provides a channel-agnostic tool for analyzing and performance optimization of radio systems that operate in the UR regime. Furthermore, the unified model is particularly useful in emerging measurement campaigns for empirical characterization of wireless channels in the regime of low outages. Finally, the asymptotic analysis can serve as an underlying building block for designing more elaborate, higher-layer technologies for URC. We showcase this by applying the power law results to analyze the performance of receiver diversity schemes and obtain a new simplified expression for Maximum Ratio Combining (MRC) that can be used to analyze multiple antenna wireless systems in an UR regime.
Original languageEnglish
JournalIEEE Transactions on Wireless Communications
ISSN1536-1276
Publication statusAccepted/In press - 12 Feb 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Preamble Detection in NB-IoT Random Access with Limited-Capacity Backhaul

Preamble Detection in NB-IoT Random Access with Limited-Capacity Backhaul

Hien, T. Q., Wang, Z., Kim, S. W., Nielsen, J. J. & Popovski, P., Feb 2019, (Accepted/In press) Proceedings of IEEE ICC'19.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

Original languageEnglish
Title of host publicationProceedings of IEEE ICC'19
Publication dateFeb 2019
Publication statusAccepted/In press - Feb 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Multi-Channel Access Solutions for 5G New Radio

Multi-Channel Access Solutions for 5G New Radio

Mahmood, N. H., Laselva, D., Palacios, D., Emara, M., Filippou, M. C., Kim, D. M. & de-la-Bandera, I., 2019, (Submitted) In : I E E E Communications Magazine.

Research output: Contribution to journalJournal articleResearchpeer-review

The arrival of 5G New Radio Release-15 opens the door for introducing Radio Resource Management solutions targeting enhanced mobile broadband and ultra-reliable low latency communication service classes. Multi-Channel Access is a family of such multi-service solution, which enables a user equipment to aggregate radio resources from multiple sources, either from the same or from different nodes. The objective is multi-fold; throughput enhancement through access to a larger bandwidth, reliability improvement by increasing the diversity order and/or coordinated transmission/reception, or more flexible load balance and performance increase by decoupling the downlink and the uplink access points. This paper presents a number of multi-channel solutions for the 5G New Radio multi-service scenario. In particular, we discuss throughput enhancement and latency reduction concepts like multinode connectivity, carrier aggregation, downlink-uplink decoupled access and coordinated multi-point connectivity. A number of design challenges for these concepts are then highlighted, followed by novel solution proposals. All the proposed solutions are numerically validated, and found to result in significant performance gains over state-of-the-art solutions; for example, our proposed component carrier selection mechanism leads to an average median throughput gain of around 66% by means of an implicit load balance.
Original languageEnglish
JournalI E E E Communications Magazine
ISSN0163-6804
Publication statusSubmitted - 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Extremely Large Aperture Massive MIMO: Low Complexity Receiver Architectures

Extremely Large Aperture Massive MIMO: Low Complexity Receiver Architectures

Amiri, A., Angjelichinoski, M., Carvalho, E. D. & Heath Jr, R. W., 2019, (Accepted/In press) IEEE Globecom 2018 Workshops. IEEE, 6 p.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

This paper focuses on new communication paradigms arising in massive multiple-input-multiple-output systems where the antenna array at the base station is of extremely large dimension (xMaMIMO). Due to the extreme dimension of the array, xMaMIMO is characterized by spatial non-stationary field properties along the array; this calls for a multi-antenna transceiver design that is adapted to the array dimension but also its non-stationary properties. We address implementation aspects of xMaMIMO, with computational efficiency as our primary objective. To reduce the computational burden of centralized schemes, we distribute the processing into smaller, disjoint subarrays. Then, we consider several low-complexity data detection algorithms as candidates for uplink communication in crowded xMaMIMO systems. Drawing inspiration from coded random access, one of the main contributions of the paper is the design of low complexity scheme that exploits the non-stationary nature of xMaMIMO systems and where the data processing is decentralized. We evaluate the bit-error-rate performance of the transceivers in crowded xMaMIMO scenarios. The results confirm their practical potential.
Original languageEnglish
Title of host publicationIEEE Globecom 2018 Workshops
Number of pages6
PublisherIEEE
Publication date2019
Publication statusAccepted/In press - 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Software-Defined Microgrid Control for Resilience Against Denial-of-Service Attacks

Original languageEnglish
JournalIEEE Transactions on Smart Grid
ISSN1949-3053
DOI
Publication statusE-pub ahead of print - 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Hybrid Precoding for Massive MIMO Systems in Cloud RAN Architecture with Capacity-Limited Fronthauls

Original languageEnglish
JournalIEEE Journal of Selected Topics in Signal Processing
ISSN1932-4553
Publication statusSubmitted - 2019
Publication categoryResearch
Peer-reviewedYes

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PDF Icon An Experimental Study of Massive MIMO Properties in 5G Scenarios

An Experimental Study of Massive MIMO Properties in 5G Scenarios

Martinez, A. O., Nielsen, J. Ø., Carvalho, E. D. & Popovski, P., Dec 2018, In : I E E E Transactions on Antennas and Propagation. 66, 12, p. 7206-7215 10 p., 8471108.

Research output: Contribution to journalJournal articleResearchpeer-review

Three main characteristics of massive multiple-input-multiple-output (MIMO) are studied. The widespread use of these characteristics and their lack of validation motivates this paper based in measurements. First, we study the channel hardening when the number of antennas in the base station (BS) increases. Second, we focus on the channel vector orthogonality between two users. Third, we investigate the rank of the spatial covariance matrix. The data used for this paper have been obtained in two measurement campaigns with all real antennas (i.e., neither virtual arrays nor virtual users). The first one has 64 BS elements arranged in 3 configurations, and it serves 8 users with 2 antennas each. The second campaign has 128 BS elements, serving 2 users with 2 antennas each. Both campaigns include line-of-sight and nonline-of-sight scenarios, designed according to the future 5G deployment scenarios. We show the rate of channel hardening when the number of BS elements increases. We evaluate the sum rate of two users at specific distances between them. We observe the large angular spread occupied by the user.

Original languageEnglish
Article number8471108
JournalI E E E Transactions on Antennas and Propagation
Volume66
Issue number12
Pages (from-to)7206-7215
Number of pages10
ISSN0018-926X
DOI
Publication statusPublished - Dec 2018
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Common-Message Broadcast Channels with Feedback in the Nonasymptotic Regime: Stop Feedback

Common-Message Broadcast Channels with Feedback in the Nonasymptotic Regime: Stop Feedback

Trillingsgaard, K. F., Yang, W., Durisi, G. & Popovski, P., 1 Dec 2018, In : I E E E Transactions on Information Theory. 64, 12, p. 7686-7718 33 p., 8456639.

Research output: Contribution to journalJournal articleResearchpeer-review

We investigate the maximum coding rate for a given average blocklength and error probability over a $K$-user discrete memoryless broadcast channel for the scenario where a common message is transmitted using variable-length stop-feedback codes. For the point-to-point case, Polyanskiy et al. (2011) demonstrated that variable-length coding combined with stop-feedback significantly increases the speed of convergence of the maximum coding rate to capacity. This speed-up manifests itself in the absence of a square-root penalty in the asymptotic expansion of the maximum coding rate for large blocklengths, i.e., zero dispersion. In this paper, we present nonasymptotic achievability and converse bounds on the maximum coding rate of the common-message $K$-user discrete memoryless broadcast channel, which strengthen and generalize the ones reported in Trillingsgaard et al. (2015) for the two-user case. An asymptotic analysis of these bounds reveals that zero dispersion cannot be achieved for certain common-message broadcast channels (e.g., the binary symmetric broadcast channel). Furthermore, we identify conditions under which our converse and achievability bounds are tight up to the second order. Through numerical evaluations, we illustrate that our second-order expansions approximate accurately the maximum coding rate and that the speed of convergence to capacity is indeed slower than for the point-to-point case.

Original languageEnglish
Article number8456639
JournalI E E E Transactions on Information Theory
Volume64
Issue number12
Pages (from-to)7686-7718
Number of pages33
ISSN0018-9448
DOI
Publication statusPublished - 1 Dec 2018
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Common-Message Broadcast Channels with Feedback in the Nonasymptotic Regime: Full Feedback

Common-Message Broadcast Channels with Feedback in the Nonasymptotic Regime: Full Feedback

Trillingsgaard, K. F., Yang, W., Durisi, G. & Popovski, P., 1 Dec 2018, In : I E E E Transactions on Information Theory. 64, 12, p. 7719 - 7741 23 p., 8456630.

Research output: Contribution to journalJournal articleResearchpeer-review

We investigate the maximum coding rate achievable on a two-user broadcast channel for the case where a common message is transmitted with feedback using either fixed-blocklength codes or variable-length codes. For the fixed-blocklength-code setup, we establish nonasymptotic converse and achievability bounds. An asymptotic analysis of these bounds reveals that feedback improves the second-order term compared to the no-feedback case. In particular, for a certain class of anti-symmetric broadcast channels, we show that the dispersion is halved. For the variable-length-code setup, we demonstrate that the channel dispersion is zero.
Original languageEnglish
Article number8456630
JournalI E E E Transactions on Information Theory
Volume64
Issue number12
Pages (from-to)7719 - 7741
Number of pages23
ISSN0018-9448
DOI
Publication statusPublished - 1 Dec 2018
Publication categoryResearch
Peer-reviewedYes

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PDF Icon Coded Pilot Random Access for Massive MIMO Systems

Coded Pilot Random Access for Massive MIMO Systems

Sørensen, J. H., Carvalho, E. D., Stefanovic, C. & Popovski, P., Dec 2018, In : I E E E Transactions on Wireless Communications. 17, 12, p. 8035-8046 12 p.

Research output: Contribution to journalJournal articleResearchpeer-review

We present a novel access protocol for crowd scenarios in massive multiple-input multiple-output (MIMO) systems. Crowd scenarios are characterized by a large number of users with intermittent access behavior, whereas orthogonal scheduling is infeasible. In such scenarios, random access is a natural choice. The proposed access protocol relies on two essential properties of a massive MIMO system, namely, asymptotic orthogonality between user channels and asymptotic invariance of channel powers. Signal processing techniques that take advantage of these properties allow us to view a set of contaminated pilot signals as a graph code on which iterative belief propagation can be performed. This makes it possible to decontaminate pilot signals and increase the throughput of the system. Numerical evaluations show that the proposed access protocol increases the throughput by 36%, when there are 400 antennas at the base station, compared to the conventional method of slotted Additive Links On-line Hawaii Area. With 1024 antennas, the throughput is increased by 85%.

Original languageEnglish
JournalI E E E Transactions on Wireless Communications
Volume17
Issue number12
Pages (from-to)8035-8046
Number of pages12
ISSN1536-1276
DOI
Publication statusPublished - Dec 2018
Publication categoryResearch
Peer-reviewedYes

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