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Pappas, Nikolaos
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Publications (10 of 26) Show all publications
Tatino, C., Malanchini, I., Pappas, N. & Yuan, D. (2018). Maximum Throughput Scheduling for Multi-connectivity in Millimeter-Wave Networks. In: 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt): International Workshop on Resource Allocation, Cooperation and Competition in Wireless Networks (RAWNET). Paper presented at 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), Shanghai, China, May 7-11, 2018. IEEE
Open this publication in new window or tab >>Maximum Throughput Scheduling for Multi-connectivity in Millimeter-Wave Networks
2018 (English)In: 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt): International Workshop on Resource Allocation, Cooperation and Competition in Wireless Networks (RAWNET), IEEE, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Multi-connectivity is emerging as promising solution to provide reliable communications and seamless connectivity at the millimeter-wave frequency range. Due to the obstacles that cause frequent interruptions at such high frequency range, connectivity to multiple cells can drastically increase the network performance in terms of throughput and reliability by coordi- nation among the network elements. In this paper, we propose an algorithm for the link scheduling optimization that maximizes the network throughput for multi-connectivity in millimeter-wave cellular networks. The considered approach exploits a centralized architecture, fast link switching, proactive context preparation and data forwarding between millimeter-wave access points and the users. The proposed algorithm is able to numerically approach the global optimum and to quantify the potential gain of multi-connectivity in millimeter-wave cellular networks. 

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-146211 (URN)10.23919/WIOPT.2018.8362891 (DOI)000434872700066 ()9783903176003 (ISBN)9781538646212 (ISBN)
Conference
16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), Shanghai, China, May 7-11, 2018
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsEU, Horizon 2020, 643002
Note

Funding agencies: European Unions Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant [643002]; CENIIT

Available from: 2018-04-02 Created: 2018-04-02 Last updated: 2018-09-28
Pappas, N. (2018). Performance Analysis of a System with Bursty Traffic and Adjustable Transmission Times. In: 15th International Symposium on Wireless Communication System (ISWCS 2018): SS5 - Ultra-Reliable Low Latency Communications. Paper presented at ISWCS 2018, Lisbon, Portugal, 28-31 August, 2018. IEEE Communications Society
Open this publication in new window or tab >>Performance Analysis of a System with Bursty Traffic and Adjustable Transmission Times
2018 (English)In: 15th International Symposium on Wireless Communication System (ISWCS 2018): SS5 - Ultra-Reliable Low Latency Communications, IEEE Communications Society, 2018Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
IEEE Communications Society, 2018
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-149649 (URN)
Conference
ISWCS 2018, Lisbon, Portugal, 28-31 August, 2018
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsEU, Horizon 2020, 645705
Available from: 2018-07-14 Created: 2018-07-14 Last updated: 2018-08-15Bibliographically approved
Kountouris, M., Pappas, N. & Avranas, A. (2018). QoS Provisioning in Large Wireless Networks. In: 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt): Workshop on Spatial Stochastic Models for Wireless Networks (SpaSWiN). Paper presented at 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), May 7 to 11, 2018 in Shanghai, China.
Open this publication in new window or tab >>QoS Provisioning in Large Wireless Networks
2018 (English)In: 16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt): Workshop on Spatial Stochastic Models for Wireless Networks (SpaSWiN), 2018Conference paper, Published paper (Refereed)
Abstract [en]

Quality of service (QoS) provisioning in next-generation mobile communications systems entails a deep understanding of the delay performance. The delay in wireless networks is strongly affected by the traffic arrival process and the packet service process, which in turn depends on the medium access mechanisms and the signal-to-interference-plus-noise ratio (SINR). In this work, we analyze the delay of large wireless networks, where the sources are distributed as a Poisson point process. We provide analytical expressions for the service process and derive delay violation probability bounds using tools from stochastic network calculus and stochastic geometry. Furthermore, we analyze the delay performance under statistical queueing constraints imposed as limitations on buffer violation probabilities. The impact of QoS requirements, network geometry and spatial density of interferers on the throughput and delay performance is identified. Our results provide useful guidelines for resource allocation and system dimensioning to guarantee stringent delay requirements.

National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-146212 (URN)10.23919/WIOPT.2018.8362878 (DOI)000434872700053 ()9783903176003 (ISBN)9781538646212 (ISBN)
Conference
16th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), May 7 to 11, 2018 in Shanghai, China
Note

Funding agencies: Center for Industrial Information Technology (CENIIT)

Available from: 2018-04-02 Created: 2018-04-02 Last updated: 2018-06-28
Mohapatra, P., Pappas, N., Lee, J., Quek, T. Q. .. & Angelakis, V. (2018). Secure Communications for the Two-user Broadcast Channel with Random Traffic. IEEE Transactions on Information Forensics and Security, 13(9), 2294-2309
Open this publication in new window or tab >>Secure Communications for the Two-user Broadcast Channel with Random Traffic
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2018 (English)In: IEEE Transactions on Information Forensics and Security, ISSN 1556-6013, E-ISSN 1556-6021, Vol. 13, no 9, p. 2294-2309Article in journal (Refereed) Published
Abstract [en]

In this work, we study the stability region of the two-user broadcast channel (BC) with bursty data arrivals and security constraints. It is assumed that one of the receivers has a secrecy constraint, i.e., its packets need to be kept secret from the other receiver, which is defined based on SINR. The receiver with secrecy constraint has full-duplex capability to send a jamming signal for improving its service rate. The stability region of the two-user BC with secrecy constraint is characterized for the general decoding case. Then, assuming two different decoding schemes the respective stability regions are derived. The fullduplex operation of receiver results in self-interference, and the effect of imperfect self-interference cancelation on the stability region is also investigated. The stability region of the BC with a secrecy constraint, where the receivers do not have full duplex capability can be obtained as a special case of the results derived in this paper. In addition, the paper considers the problem of maximizing the saturated throughput of the queue for which there is no secrecy constraint under minimum service guarantees for the other queue. The results provide new insights on the effect of the secrecy constraint on the stability region of the BC. It is found that the stability region with secrecy constraint is sensitive to the degree of self-interference cancelation.

Place, publisher, year, edition, pages
IEEE Signal Processing Society, 2018
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-146030 (URN)10.1109/TIFS.2018.2818076 (DOI)000431896200013 ()
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Note

Funding agencies: National Research Foundation of Korea, Korea Government (MSIP) [2017R1C1B2009280]; DGIST Research and Development Program of the Ministry of Science and ICT [17-ST-02]; DGIST Research and Development Program of the Ministry of Science and ICT under ELLIIT

Available from: 2018-03-22 Created: 2018-03-22 Last updated: 2018-05-30Bibliographically approved
Pappas, N., Jeon, J., Yuan, D., Traganitis, A. & Ephremides, A. (2018). Wireless Network-Level Partial Relay Cooperation: A Stable Throughput Analysis. Journal of Communications and Networks, 20(1), 93-101
Open this publication in new window or tab >>Wireless Network-Level Partial Relay Cooperation: A Stable Throughput Analysis
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2018 (English)In: Journal of Communications and Networks, ISSN 1229-2370, E-ISSN 1976-5541, Vol. 20, no 1, p. 93-101Article in journal (Refereed) Published
Abstract [en]

In this work, we study the benefit of partial relay cooperation. We consider a two-node system consisting of one source and one relay node transmitting information to a common destination. The source and the relay have external traffic and in addition, the relay is equipped with a flow controller to regulate the incoming traffic from the source node. The cooperation is performed at the network level. A collision channel with erasures is considered. We provide an exact characterization of the stability region of the system and we also prove that the system with partial cooperation is always better or at least equal to the system without the flow controller. 

Keywords
Network level cooperation, partial cooperation, queueing, random access, relay, stability region.
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-145635 (URN)10.1109/JCN.2018.000009 (DOI)000428149300009 ()
Funder
ELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsEU, Horizon 2020, 645705EU, FP7, Seventh Framework Programme, 612361EU, Horizon 2020, 642743
Note

Funding agencies: People Programme (Marie Curie Actions) of the European Unions Seventh Framework Programme FP7/under REA [[612361]-SOrBet]; EU project DECADE [H2020-MSCA-2014-RISE: 645705]; European Union [642743]; MURI [W911NF-08-1-0238]; NSF [CCF1420651]; ONR [N00014141

Available from: 2018-03-10 Created: 2018-03-10 Last updated: 2018-04-11Bibliographically approved
Kosta, A., Pappas, N. & Angelakis, V. (2017). Age of Information: A New Concept, Metric, and Tool. Foundations and Trends in Networking, 12(3), 162-259
Open this publication in new window or tab >>Age of Information: A New Concept, Metric, and Tool
2017 (English)In: Foundations and Trends in Networking, ISSN 1554-057X, Vol. 12, no 3, p. 162-259Article in journal (Refereed) Published
Abstract [en]

Age of information (AoI) was introduced in the early 2010s as a notion to characterize the freshness of the knowledge a system has about a process observed remotely. AoI was shown to be a fundamentally novel metric of timeliness, significantly different, to existing ones such as delay and latency. The importance of such a tool is paramount, especially in contexts other than transport of information, since communication takes place also to control, or to compute, or to infer, and not just to reproduce messages of a source. This volume comes to present and discuss the first body of works on AoI and discuss future directions that could yield more challenging and interesting research.

Place, publisher, year, edition, pages
Deft: Now Publishers Inc., 2017
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-149054 (URN)10.1561/1300000060 (DOI)9781680833607 (ISBN)9781680833614 (ISBN)
Available from: 2018-06-26 Created: 2018-06-26 Last updated: 2018-06-26Bibliographically approved
Kosta, A., Pappas, N. & Angelakis, V. (2017). Age of Information: A New Concept, Metric, and Tool. Boston - Delft: Now Publishers Inc.
Open this publication in new window or tab >>Age of Information: A New Concept, Metric, and Tool
2017 (English)Book (Refereed)
Abstract [en]

In an increasingly networked world in which information is becoming increasingly actual, how can a system know with certainty just how fresh the information on a remote system is? Much work has been done on delay or latency in systems, but only recently has the concept of the freshness of information in or about a system become quantifiable. This is termed the Age of Information.

Age of Information provides a whole new set of metrics and tools that can be used to characterize the freshness of information in communications, control and, indeed, information systems. In its early development, this monograph provides the reader with an easy-to-read tutorial-like introduction into this novel approach of dealing with information within systems. A critical summary of the work to date details the concept for the reader. A description of the fundamentals of the performance metrics is then presented before showing how the approach can be used as a tool in improving metrics in other contexts.

The survey and tutorial nature of this monograph will save any researcher or student considerable time in understanding the basics of Age of Information, which is destined to become an important research topic in networked systems.

Place, publisher, year, edition, pages
Boston - Delft: Now Publishers Inc., 2017. p. 110
Series
Foundations and Trends® in Networking, ISSN 1554-057X, E-ISSN 1554-0588 ; 12(3)
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-149022 (URN)10.1561/1300000060 (DOI)9781680833607 (ISBN)9781680833614 (ISBN)
Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2018-06-26Bibliographically approved
Chen, B., Chen, Z., Pappas, N., Yuan, D. & Zhang, J. (2017). Modeling and Analysis of MPTCP Proxy-based LTE-WLAN Path Aggregation. In: IEEE Global Communications Conference (GLOBECOM) 2017: . Paper presented at IEEE Global Communications Conference (GLOBECOM), Singapore, December 4-8, 2017. IEEE Communications Society
Open this publication in new window or tab >>Modeling and Analysis of MPTCP Proxy-based LTE-WLAN Path Aggregation
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2017 (English)In: IEEE Global Communications Conference (GLOBECOM) 2017, IEEE Communications Society, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Long Term Evolution (LTE)-Wireless Local Area Network (WLAN) Path Aggregation (LWPA) based on Multi- path Transmission Control Protocol (MPTCP) has been under standardization procedure as a promising and cost-efficient solution to boost Downlink (DL) data rate and handle the rapidly increasing data traffic. This paper aims at providing tractable analysis for the DL performance evaluation of large-scale LWPA networks with the help of tools from stochastic geometry. We consider a simple yet practical model to determine under which conditions a native WLAN Access Point (AP) will work under LWPA mode to help increasing the received data rate. Using stochastic spatial models for the distribution of WLAN APs and LTE Base Stations (BSs), we analyze the density of active LWPA- mode WiFi APs in the considered network model, which further leads to closed-form expressions on the DL data rate and area spectral efficiency (ASE) improvement. Our numerical results illustrate the impact of different network parameters on the performance of LWPA networks, which can be useful for further performance optimization. 

Place, publisher, year, edition, pages
IEEE Communications Society, 2017
Series
IEEE Global Communications Conference, ISSN 2334-0983
Keywords
LTE, WiFi, Path Aggregation, MPTCP, Stochastic Geometry
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:liu:diva-140159 (URN)10.1109/GLOCOM.2017.8254058 (DOI)000428054300138 ()
Conference
IEEE Global Communications Conference (GLOBECOM), Singapore, December 4-8, 2017
Projects
DECADE (Deploying High Capacity Dense Small Cell Heterogeneous Networks)
Funder
EU, Horizon 2020
Note

Funding agencies: This work was supported in part by the Swedish Foundation for Strategic Research (SSF), the Swedish Research Council (VR), ELLIIT, the joint research project DECADE (Deploying High Capacity Dense Small Cell Heterogeneous Networks), within the Research and Innovation Staff Exchange (RISE) scheme of the European Horizon 2020 Framework Program, under contract number 645705.

Available from: 2017-09-01 Created: 2017-09-01 Last updated: 2018-04-26Bibliographically approved
Avgouleas, I., Pappas, N. & Angelakis, V. (2017). Scheduling Services on an IoT Device Under Time-Weighted Pricing. In: IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): Workshop on "Communications for Networked Smart Cities". Paper presented at IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Montreal, QC, Canada, October 08-13, 2017. IEEE conference proceedings
Open this publication in new window or tab >>Scheduling Services on an IoT Device Under Time-Weighted Pricing
2017 (English)In: IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): Workshop on "Communications for Networked Smart Cities", IEEE conference proceedings, 2017Conference paper, Published paper (Refereed)
Abstract [en]

The emerging vision of smart cities necessitates the use of Internet of Things (IoT) network devices to implement sustainable solutions that will improve the operations of urban areas. A massive amount of smart cities services may demand allocation of computational resources, such as processing power or storage, that IoT devices offer. Within this context, we present an IoT network device comprising interfaces with one specific computational resource available. The efficient utilization of available IoT resources would improve the Quality of Service (QoS) of the IoT network that serves the smart city. All resource allocations must be completed within a given scheduling window and every service is parametrized by a pricing weight function to indicate its tolerance to be served at the beginning of the scheduling window. We propose a mathematical optimization formulation to minimize the total cost of allocating all demands within the scheduling window considering the tolerance level of each service at the same time. Moreover, we prove that the problem is computationally hard and we provide numerical results to gain insight into the impact of different pricing weight functions on the allocations’ distribution within the scheduling window.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2017
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:liu:diva-140105 (URN)10.1109/PIMRC.2017.8292656 (DOI)000426970903002 ()9781538635292 (ISBN)9781538635315 (ISBN)
Conference
IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), Montreal, QC, Canada, October 08-13, 2017
Funder
EU, FP7, Seventh Framework Programme
Available from: 2017-08-29 Created: 2017-08-29 Last updated: 2018-05-15Bibliographically approved
Pappas, N., Kountouris, M., Jeon, J., Ephremides, A. & Traganitis, A. (2016). Effect of Energy Harvesting on Stable Throughput in Cooperative Relay Systems. Journal of Communications and Networks, 18(2), 261-269
Open this publication in new window or tab >>Effect of Energy Harvesting on Stable Throughput in Cooperative Relay Systems
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2016 (English)In: Journal of Communications and Networks, ISSN 1229-2370, E-ISSN 1976-5541, Vol. 18, no 2, p. 261-269Article in journal (Refereed) Published
Abstract [en]

In this paper, the impact of energy constraints on a two hop network with a source, a relay and a destination under random medium access is studied. A collision channel with erasures is considered, and the source and the relay nodes have energy harvesting capabilities and an unlimited battery to store the harvested energy. Additionally, the source and the relay node have external traffic arrivals and the relay forwards a fraction of the source nodes traffic to the destination; the cooperation is performed at the network level. An inner and an outer bound of the stability region for a given transmission probability vector are obtained. Then, the closure of the inner and the outer bound is obtained separately and they turn out to be identical. This work is not only a step in connecting information theory and networking, by studying the maximum stable throughput region metric but also it taps the relatively unexplored and important domain of energy harvesting and assesses the effect of that on this important measure.

Place, publisher, year, edition, pages
KOREAN INST COMMUNICATIONS SCIENCES (K I C S), 2016
Keywords
Energy harvesting; network-level cooperation; random access; relay; stable throughput
National Category
Telecommunications
Identifiers
urn:nbn:se:liu:diva-129176 (URN)000376225200013 ()
Note

Funding Agencies|People Programme (Marie Curie Actions) of the European Unions Seventh Framework Programme FP7 under REA grant [612361]; MURI grant [W911NF-08-1-0238]; NSF [CCF1420651]; ONR [N000141410107]

DOI does not work: 10.1109/JCN.2016.000035

Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2018-03-13
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