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Avgouleas, Ioannis
Publications (7 of 7) Show all publications
Avgouleas, I. M. (2019). Cooperation and Resource Allocation in Wireless Networking towards the IoT. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Cooperation and Resource Allocation in Wireless Networking towards the IoT
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The Internet of Things (IoT) should be able to react with minimal human intervention and contribute to the Artificial Intelligence (AI) era requiring real-time and scalable operation under heterogeneous network infrastructures. This thesis investigates how cooperation and allocation of resources can contribute to the evolution of future wireless networks supporting the IoT.

First, we examine how to allocate resources to IoT services which run on devices equipped with multiple network interfaces. The resources are heterogeneous and not interchangeable, and their allocation to a service can be split among different interfaces. We formulate an optimization model for this allocation problem, prove its complexity, and derive two heuristic algorithms to approximate the solution in large instances of the problem.

The concept of virtualization is promising towards addressing the heterogeneity of IoT resources by providing an abstraction layer between software and hardware. Network function virtualization (NFV) decouples traditional network operations such a routing from proprietary hardware platforms and implements them as software entities known as virtualized network functions (VNFs). In the second paper, we study how VNF demands can be allocated to Virtual Machines (VMs) by considering the completion-time tolerance of the VNFs. We prove that the problem is NP-complete and devise a subgradient optimization algorithm to provide near-optimal solutions. Our numerical results demonstrate the effectiveness of our algorithm compared to two benchmark algorithms.

Furthermore, we explore the potential of using intermediate nodes, the so-called relays, in IoT networks. In the third paper, we study a multi-user random-access network with a relay node assisting users in transmitting their packets to a destination node. We provide analytical expressions for the performance of the relay's queue and the system throughput. We optimize the relay’s operation parameters to maximize the network-wide throughput while maintaining the relay's queue stability. A stable queue at relay guarantees finite delay for the packets. Furthermore, we study the effect of the wireless links' signal-to-interference-plusnoise ratio (SINR) threshold and the self-interference (SI) cancellation on the per-user and network-wide throughput.

Additionally, caching at the network edge has recently emerged as an encouraging solution to offload cellular traffic and improve several performance metrics of the network such as throughput, delay and energy efficiency. In the fourth paper, we study a wireless network that serves two types of traffic: cacheable and non-cacheable traffic. In the considered system, a wireless user with cache storage requests cacheable content from a data center connected with a wireless base station. The user can be assisted by a pair of wireless helpers that exchange non-cacheable content as well. We devise the system throughput and the delay experienced by the user and provide numerical results that demonstrate how they are affected by the non-cacheable packet arrivals, the availability of caching helpers, the parameters of the caches, and the request rate of the user.

Finally, in the last paper, we consider a time-slotted wireless system that serves both cacheable and non-cacheable traffic with the assistance of a relay node. The latter has storage capabilities to serve both types of traffic. We investigate how allocating the storage capacity to cacheable and non-cacheable traffic affects the system throughput. Our numerical results provide useful insights into the system throughput e.g., that it is not necessarily beneficial to increase the storage capacity for the non-cacheable traffic to realize better throughput at the non-cacheable destination node.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. p. 42
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 2016
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-161732 (URN)10.3384/diss.diva-161732 (DOI)9789175190044 (ISBN)
Public defence
2019-12-03, K3, Kåkenhus, Campus Norrköping, Norrköping, 13:15 (English)
Opponent
Supervisors
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Avgouleas, I., Yuan, D., Pappas, N. & Angelakis, V. (2019). Virtual Network Functions Scheduling under Delay-Weighted Pricing. IEEE Networking Letters, 1-1
Open this publication in new window or tab >>Virtual Network Functions Scheduling under Delay-Weighted Pricing
2019 (English)In: IEEE Networking Letters, E-ISSN 2576-3156, p. 1-1Article in journal (Refereed) Epub ahead of print
Abstract [en]

We consider a cost minimization problem for High Volume Servers (HVS) equipped with Virtual Machines (VMs) to serve Virtual Network Functions (VNF) demands for resources. Given a scheduling period, a central scheduler decides which VM to use for each VNF demand. Each VM can be activated or disabled with different costs. Each VNF has a delay-weighted pricing function to indicate its completion time tolerance. We prove the NP-completeness of the problem and develop an algorithm based on Lagrangian relaxation and subgradient optimization to deal with this computational complexity. Finally, our numerical results demonstrate our algorithm’s effectiveness compared to two benchmarks.

Keywords
Optimization, Linear programming, Resource management, Pricing, Network function virtualization, Complexity theory, Servers
National Category
Computer Engineering
Identifiers
urn:nbn:se:liu:diva-161731 (URN)10.1109/LNET.2019.2937237 (DOI)
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Avgouleas, I. (2017). IoT Networking Resource Allocation and Cooperation. (Licentiate dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>IoT Networking Resource Allocation and Cooperation
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The Internet of Things (IoT) promises that "anything that can be connected, will be connected". It comprises of Information and Communication Technologies that interconnect billions of physical and visual things with some "basic" intelligence. The emerging IoT services will be able to react with minimal human intervention and further contribute to the big data era that requires real-time, ultrareliable, ubiquitous, scalable, and heterogeneous operation.

This thesis is the result of our investigations on problems dealing with the evolution of such technologies. First, we explore the potential of using relay i.e., intermediate, nodes that assist users to transmit their packets in a a cellular network. Paper I provides insights into how adapting the cooperation of the relay's receiver and transmitter optimizes the network-wide throughput while the relay's queue stability is guaranteed.

The next part of the thesis copes with the resource allocation of services on IoT devices equipped with multiple network interfaces. The resources are heterogeneous and can be split among dierent interfaces. Additionally, they are not interchangeable. In paper II, we develop optimization models for this resource allocation problem, prove the complexity of the models, and derive results that give intuition into the problems. Moreover, we propose algorithms that approximate the optimal solution and show under which circumstances this is possible.

Finally, in paper III, we present a resource allocation problem specically for smart cities services. In comparison to the previous problem denition, resources are of one type but the IoT network device can oer capacities that vary over time. Furthermore, services have a tolerance regarding their preferred scheduling, namely, their allocation over time. We parametrize each service with a pricing function to indicate its tolerance to be served at the beginning of the scheduling window. We prove that the problem is computationally hard and provide numerical results to gain insight into how different pricing weight functions impact the allocations' distribution within the scheduling window.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2017. p. 20
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1785
National Category
Communication Systems Telecommunications Computer Engineering Computer Sciences Computer Systems
Identifiers
urn:nbn:se:liu:diva-139891 (URN)LiU-TEK-LIC-2017 (Local ID)9789176854617 (ISBN)LiU-TEK-LIC-2017 (Archive number)LiU-TEK-LIC-2017 (OAI)
Supervisors
Funder
EU, FP7, Seventh Framework Programme, FP7/2007-2013: Grant 609094 (RERUM), 612361 (SOrBet), 324515 (MESH-WISE), 645705 (DECADE), 318992 (WINDOW)
Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2019-05-09Bibliographically approved
Avgouleas, I., Pappas, N. & Angelakis, V. (2017). Scheduling Services on an IoT Device Under Time-Weighted Pricing. In: Conference Proceedings 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 (pp. 1-5). IEEE conference proceedings
Open this publication in new window or tab >>Scheduling Services on an IoT Device Under Time-Weighted Pricing
2017 (English)In: Conference Proceedings IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC): Workshop on "Communications for Networked Smart Cities", IEEE conference proceedings, 2017, p. 1-5Conference 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
Series
Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), E-ISSN 2166-9589 ; 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)9781538635308 (ISBN)9781538635322 (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: 2019-05-10Bibliographically approved
Avgouleas, I., Pappas, N. & Angelakis, V. (2015). Cooperative Wireless Networking with Probabilistic On/Off Relaying. In: 2015 IEEE 81ST VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING): . Paper presented at 81st IEEE Vehicular Technology Conference (VTC Spring). IEEE
Open this publication in new window or tab >>Cooperative Wireless Networking with Probabilistic On/Off Relaying
2015 (English)In: 2015 IEEE 81ST VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), IEEE , 2015Conference paper, Published paper (Refereed)
Abstract [en]

In this work, we investigate the operation of energy efficient relay nodes assisting the transmission of packets from a number of users to a destination node. We study the impact of switching randomly a fraction of the relays on and off to the aggregate throughput, the average queue size and delay per packet of systems with relays transmitting in either Full-or Half-Duplex mode and under different channel transmissions characteristics. Furthermore, we prove analytically and illustrate via simulation means how these network metrics are affected.

Place, publisher, year, edition, pages
IEEE, 2015
Series
IEEE Vehicular Technology Conference Proceedings, ISSN 1550-2252
National Category
Civil Engineering
Identifiers
urn:nbn:se:liu:diva-127067 (URN)10.1109/VTCSpring.2015.7145762 (DOI)000371404700177 ()978-1-4799-8088-8 (ISBN)
Conference
81st IEEE Vehicular Technology Conference (VTC Spring)
Available from: 2016-04-13 Created: 2016-04-13 Last updated: 2019-05-09
Angelakis, V., Avgouleas, I., Pappas, N. & Yuan, D. (2015). Flexible allocation of heterogeneous resources to services on an IoT device. In: 2015 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS): . Paper presented at 2015 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS). April 26 2015-May 1 2015, Hong Kong (pp. 99-100). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Flexible allocation of heterogeneous resources to services on an IoT device
2015 (English)In: 2015 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), Institute of Electrical and Electronics Engineers (IEEE), 2015, p. 99-100Conference paper, Published paper (Refereed)
Abstract [en]

In the Internet of Things (IoT), devices and gateways may be equipped with multiple, heterogeneous network interfaces which should be utilized by a large number of services. In this work, we model the problem of assigning services' resource demands to a device's heterogeneous interfaces and give a Mixed Integer Linear Program (MILP) formulation for it. For meaningful instance sizes the MILP model gives optimal solutions to the presented computationally-hard problem. We provide insightful results discussing the properties of the results on the properties of the derived solutions with respect to the splitting of services to different interfaces.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2015
Series
IEEE Conference on Computer Communications Workshops, ISSN 2159-4228
Keywords
Internet;Internet of Things;integer programming;linear programming;network interfaces;resource allocation;Internet of Things;IoT device;MILP formulation;flexible allocation;heterogeneous interface;heterogeneous network interface;heterogeneous resource;mixed integer linear program formulation;service resource demand;Optimization
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-129442 (URN)10.1109/INFCOMW.2015.7179362 (DOI)000380561200055 ()978-1-4673-7131-5 (ISBN)
Conference
2015 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS). April 26 2015-May 1 2015, Hong Kong
Available from: 2016-06-19 Created: 2016-06-19 Last updated: 2019-05-09
Avgouleas, I., Angelakis, V. & Pappas, N. (2014). Utilizing multiple full-duplex relays in wireless systems with multiple packet reception. In: 2014 IEEE 19th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD): . Paper presented at 2014 IEEE 19th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks(CAMAD. 1-3 Dec. 2014, Athens (pp. 193-197). IEEE
Open this publication in new window or tab >>Utilizing multiple full-duplex relays in wireless systems with multiple packet reception
2014 (English)In: 2014 IEEE 19th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), IEEE, 2014, p. 193-197Conference paper, Published paper (Refereed)
Abstract [en]

Relay nodes with physical layer cooperation have been used extensively to assist users' transmissions in wireless networks. This network level cooperation has been lately been gaining popularity and analytical expressions of the performance of a network with up to two relay nodes exist in recent literature. In this work, we give simulation results outlining the potential network level benefits of using multiple full-duplex relay nodes. We examine configurations where multiple full-duplex transceivers offer consistent improvement and provide guidelines on using them different network conditions.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
radio reception;radio transceivers;relay networks (telecommunication);wireless channels;multiple full-duplex relay nodes;multiple full-duplex transceivers;multiple packet reception;network level cooperation;physical layer cooperation;wireless networks;wireless systems;Aggregates;Interference;Relays;Signal to noise ratio;Throughput;Wireless networks
National Category
Communication Systems
Identifiers
urn:nbn:se:liu:diva-129440 (URN)10.1109/CAMAD.2014.7033233 (DOI)000380484700040 ()978-1-4799-5725-5 (ISBN)
Conference
2014 IEEE 19th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks(CAMAD. 1-3 Dec. 2014, Athens
Available from: 2016-06-19 Created: 2016-06-19 Last updated: 2019-05-09
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