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Publications (10 of 30) Show all publications
Hofmann, S., Megas, V., Ozger, M., Schupke, D., Fitzek, F. H. & Cavdar, C. (2019). Combined Optimal Topology Formation and Rate Allocation for Aircraft to Aircraft Communications. In: IEEE International Conference on Communications: . Paper presented at 2019 IEEE International Conference on Communications, ICC 2019; Shanghai International Convention Center, Shanghai; China; 20 May 2019 through 24 May 2019. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8761882.
Open this publication in new window or tab >>Combined Optimal Topology Formation and Rate Allocation for Aircraft to Aircraft Communications
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2019 (English)In: IEEE International Conference on Communications, Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8761882Conference paper, Published paper (Refereed)
Abstract [en]

Providing broadband in-flight Internet connectivity to aircraft is challenging. Today's options include satellite communications (SC) and direct air-to-ground communication (DA2GC). To overcome data rate, delay and cost limitations of SC and coverage limitations of DA2GC, one can extend DA2GC with air-to-air communication (A2AC) by enabling multi-hop communication. To investigate the A2AC performance, we construct a mixed integer linear programming (MILP) problem of DA2GC and A2AC, jointly considering interference in topology formation and flow assignment. Our objective is to maximize the number of aircraft that can be connected with a given specific minimum data rate threshold. The evaluation is performed for low aircraft density scenarios over the North Atlantic. We show that in the investigated scenarios, over 90 % of aircraft can have at least 50 Mbps, some being up to 1600 kilometers away from the closest base station (BS). Furthermore, we identify antenna capabilities as an important factor for A2AC performance.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Series
IEEE International Conference on Communications, ISSN 15503607
Keywords
air-to-air communication, direct air-to-ground communication, mixed integer linear programming, rate allocation, topology formation
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-257939 (URN)10.1109/ICC.2019.8761882 (DOI)2-s2.0-85070206236 (Scopus ID)9781538680889 (ISBN)
Conference
2019 IEEE International Conference on Communications, ICC 2019; Shanghai International Convention Center, Shanghai; China; 20 May 2019 through 24 May 2019
Note

QC 20190909

Available from: 2019-09-09 Created: 2019-09-09 Last updated: 2019-09-09Bibliographically approved
Mahmood, A., Hossain, A. M., Cavdar, C. & Gidlund, M. (2019). Energy-Reliability Aware Link Optimization for Battery-Powered IoT Devices With Nonideal Power Amplifiers. IEEE Internet of Things Journal, 6(3), 5058-5067
Open this publication in new window or tab >>Energy-Reliability Aware Link Optimization for Battery-Powered IoT Devices With Nonideal Power Amplifiers
2019 (English)In: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 6, no 3, p. 5058-5067Article in journal (Refereed) Published
Abstract [en]

In this paper, we study cross-layer optimization of low-power wireless links for reliability-aware applications while considering both the constraints and the nonideal characteristics of the hardware in Internet-of-Things (IoT) devices. Specifically, we define an energy consumption (EC) model that captures the energy cost-of transceiver circuitry, power amplifier (PA), packet error statistics, packet overhead, etc.-in delivering a useful data bit. We derive the EC models for an ideal and two realistic nonlinear PA models. To incorporate packet error statistics, we develop a simple, in the form of elementary functions, and accurate closed-form packet error rate approximation in Rayleigh block-fading. Using the EC models, we derive energy-optimal yet reliability and hardware compliant conditions for limiting unconstrained optimal signal-to-noise ratio (SNR), and payload size. Together with these conditions, we develop a semianalytic algorithm for resource-constrained IoT devices to jointly optimize parameters on physical (modulation size, SNR) and medium access control (payload size and the number of retransmissions) layers in relation to link distance. Our results show that despite reliability constraints, the common notion-higherorder M-ary modulations are energy optimal for short-range communication-prevails, and can provide up to 180% lifetime extension as compared to often used OQPSK modulation in IoT devices. However, the reliability constraints reduce both their range and the energy efficiency, while nonideal traditional PA reduces the range further by 50% and diminishes the energy gains unless a better PA is used.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Cross-layer design, energy-efficiency, Internet-of-Things (IoT), nonlinear power amplifiers (PAs), reliability, short-range communication
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-255450 (URN)10.1109/JIOT.2019.2895228 (DOI)000472596200092 ()2-s2.0-85067841416 (Scopus ID)
Note

QC 20190820

Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2019-08-20Bibliographically approved
Masoudi, M. (2019). Green Mobile Networks for 5G and Beyond. IEEE Access
Open this publication in new window or tab >>Green Mobile Networks for 5G and Beyond
2019 (English)In: IEEE Access, E-ISSN 2169-3536Article in journal (Refereed) Published
Abstract [en]

The heated 5G network deployment race has already begun with the rapid progress in standardization efforts, backed by the current market availability of 5G-enabled network equipment, ongoing 5G spectrum auctions, early launching of non-standalone 5G network services in a few countries, among others. In this article, we study current and future wireless networks from the viewpoint of energy efficiency (EE) and sustainability to meet the planned network and service evolution towards, along, and beyond 5G, as also inspired by the findings of the EU Celtic-Plus SooGREEN Project. We highlight the opportunities seized by the project efforts to enable and enrich this green nature of the network as compared to existing technologies. In specific, we present innovative means proposed in SooGREEN to monitor and evaluate EE in 5G networks and beyond. Further solutions are presented to reduce energy consumption and carbon footprint in the different network segments. The latter spans proposed virtualized/cloud architectures, efficient polar coding for fronthauling, mobile network powering via renewable energy and smart grid integration, passive cooling, smart sleeping modes in indoor systems, among others. Finally, we shed light on the open opportunities yet to be investigated and leveraged in future developments.

National Category
Communication Systems
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-255670 (URN)10.1109/ACCESS.2019.2932777 (DOI)
Projects
EU Celtic Plus Project SooGREEN: Service-Oriented Optimization of Green Mobile Networks
Available from: 2019-08-06 Created: 2019-08-06 Last updated: 2019-09-11
Vondra, M., Dinc, E. & Cavdar, C. (2018). Coordinated resource allocation scheme for 5G direct air-to-ground communication. In: 24th European Wireless 2018 "Wireless Futures in the Era of Network Programmability", EW 2018: . Paper presented at 24th European Wireless Conference 2018: Wireless Futures in the Era of Network Programmability, EW 2018, 2 May 2018 through 4 May 2018 (pp. 137-143). VDE Verlag GmbH
Open this publication in new window or tab >>Coordinated resource allocation scheme for 5G direct air-to-ground communication
2018 (English)In: 24th European Wireless 2018 "Wireless Futures in the Era of Network Programmability", EW 2018, VDE Verlag GmbH, 2018, p. 137-143Conference paper, Published paper (Refereed)
Abstract [en]

There is an increasing demand for in-flight broadband connectivity. Some airlines are already deployed satellite-based solutions, which have low data rate and high latency. In order to tackle these problems, direct air-to-ground communication (DA2GC), where a direct link between a ground station and an airplane is established, is a promising solution. The resource utilization in DA2GC systems can be enhanced with the introduction of multi-user beamforming techniques, where each airplane has its dedicated beam and exploits a larger portion of the spectrum available to DA2GC. Even with multiuser beamforming technique, some airplanes may experience low data rates due to interference caused by beams aimed at airplanes in the mutual vicinity. The probability that two or more beams will interfere is higher with longer inter-site distance or wider beamwidth, which is often the case for DA2GC systems. To address significant research problem, we propose a coordinated resource allocation scheme with beam selection and spectrum allocation. The proposed beam selection scheme coordinates the neighboring base stations such that the number of airplanes sharing the same beam is minimized. In addition, the proposed coordinated spectrum allocation scheme maximizes the minimum amount of spectrum dedicated for each airplane. According to our results, the proposed coordinated beam selection with efficient spectrum allocation improves average capacity available per airplane by 60% in comparison with the uncoordinated scheme.

Place, publisher, year, edition, pages
VDE Verlag GmbH, 2018
Keywords
5G networks, DA2GC, Multi-user beamforming, SDMA, Space division multiple access, 5G mobile communication systems, Aircraft, Beamforming, Resource allocation, Satellite communication systems, Air-to-ground communications, Beamforming technique, Broadband connectivity, Multi-user, Resource allocation schemes, Spectrum-allocation scheme
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-236377 (URN)2-s2.0-85050010079 (Scopus ID)9783800745609 (ISBN)
Conference
24th European Wireless Conference 2018: Wireless Futures in the Era of Network Programmability, EW 2018, 2 May 2018 through 4 May 2018
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-05Bibliographically approved
Cavdar, C., Gera, D., Ghosh, A., Hofmann, S., Nordlow, A. & Schupke, D. (2018). Demonstration of an Integrated 5G Network in an Aircraft Cabin Environment. In: 2018 IEEE/AIAA 37TH DIGITAL AVIONICS SYSTEMS CONFERENCE (DASC): . Paper presented at IEEE/AIAA 37th Digital Avionics Systems Conference (DASC), SEP 23-27, 2018, London, ENGLAND (pp. 334-343). IEEE
Open this publication in new window or tab >>Demonstration of an Integrated 5G Network in an Aircraft Cabin Environment
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2018 (English)In: 2018 IEEE/AIAA 37TH DIGITAL AVIONICS SYSTEMS CONFERENCE (DASC), IEEE , 2018, p. 334-343Conference paper, Published paper (Refereed)
Abstract [en]

The wireless communications finds many applications inside an aircraft cabin, in terms of Passenger and Crew Communications as well as Machine Type Communications (MTC). The aircraft cabin is a challenging environment and the different wireless technologies must be adequately tested and adapted to achieve maximum performance. In this regard, an aircraft environment has been analyzed in this paper for an in-cabin wireless system implementation and the measurement results have been further evaluated. This is an integrated system for the technologies of LTE, LAA and NB-IoT for the potential use-cases of Passenger Connectivity, On-Board Sensing, Cargo Tracking and Passenger Announcement. Results have then been summarized within the scope of this paper.

Place, publisher, year, edition, pages
IEEE, 2018
Series
IEEE-AIAA Digital Avionics Systems Conference, ISSN 2155-7195
Keywords
Aircraft Connectivity, Direct Air-to-Ground Communications, LAA, LTE, Machine Type Communications
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-242203 (URN)10.1109/DASC.2018.8569540 (DOI)000455217900049 ()2-s2.0-85060661069 (Scopus ID)978-1-5386-4112-5 (ISBN)
Conference
IEEE/AIAA 37th Digital Avionics Systems Conference (DASC), SEP 23-27, 2018, London, ENGLAND
Note

QC 20190128

Available from: 2019-01-28 Created: 2019-01-28 Last updated: 2019-06-26Bibliographically approved
Hossain, M. M., Cavdar, C., Bjornson, E. & Jantti, R. (2018). Energy Saving Game for Massive MIMO: Coping With Daily Load Variation. IEEE Transactions on Vehicular Technology, 67(3), 2301-2313
Open this publication in new window or tab >>Energy Saving Game for Massive MIMO: Coping With Daily Load Variation
2018 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 67, no 3, p. 2301-2313Article in journal (Refereed) Published
Abstract [en]

Massive MIMO (MM) is one of the leading technologies that can cater for very high capacity demand. However, energy consumption of MM systems needs to be load adaptive in order to cope with the significant temporal load variations (TLV) over a day. In this paper, we propose a game-theoretic model for studying load adaptive multicell massive MIMO system where each base station (BS) adapts the number of antennas to the TLV in order to maximize the downlink energy efficiency (EE). The utility function considered here is defined as the number of bits transferred per Joule of energy. In order to incorporate the TLV, the load at each BS is modeled as an M/G/m/m state dependent queue under the assumption that the network is dimensioned to serve a maximum number of users at the peak load. The EE maximization problem is formulated in a game theoretic framework where the number of antennas to be used by a BS is determined through the best response iteration. This load adaptive system achieves around 24% higher EE and saves around 40% energy compared to a baseline system where the BSs always run with the fixed number of antennas that is most energy efficient at the peak load and that can be switched OFF when there is no traffic.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Massive MIMO, energy efficiency, M/G/m/m queue, game theory
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:kth:diva-226226 (URN)10.1109/TVT.2017.2769163 (DOI)000427863000038 ()2-s2.0-85032734158 (Scopus ID)
Note

QC 20180531

Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2018-05-31Bibliographically approved
Masoudi, M., Azari, A., Yavuz, E. A. & Cavdar, C. (2018). Grant-Free Radio Access IoT Networks: Scalability Analysis in Coexistence Scenarios. In: IEEE International Conference on Communications: . Paper presented at 2018 IEEE International Conference on Communications, ICC 2018, 20 May 2018 through 24 May 2018. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Grant-Free Radio Access IoT Networks: Scalability Analysis in Coexistence Scenarios
2018 (English)In: IEEE International Conference on Communications, Institute of Electrical and Electronics Engineers Inc. , 2018Conference paper, Published paper (Refereed)
Abstract [en]

IoT networks with grant-free radio access, like SigFox and LoRa, offer low-cost durable communications over unlicensed band. These networks are becoming more and more popular due to the ever-increasing need for ultra durable, in terms of battery lifetime, IoT networks. Most studies evaluate the system performance assuming single radio access technology deployment. In this paper, we study the impact of coexisting competing radio access technologies on the system performance. Considering K technologies, defined by time and frequency activity factors, bandwidth, and power, which share a set of radio resources, we derive closed-form expressions for the successful transmission probability, expected battery lifetime, and experienced delay as a function of distance to the serving access point. Our analytical model, which is validated by simulation results, provides a tool to evaluate the coexistence scenarios and analyze how introduction of a new coexisting technology may degrade the system performance in terms of success probability and battery lifetime. We further investigate solutions in which this destructive effect could be compensated, e.g., by densifying the network to a certain extent and utilizing joint reception.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2018
Keywords
Battery lifetime, Interference modelling, IoT, LoRa, LPWA network, Cellular radio systems, Electric batteries, Internet of things, Radio communication, Closed-form expression, Radio access technologies, Scalability analysis, Success probabilities, Transmission probabilities, Radio transmission
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-238064 (URN)10.1109/ICC.2018.8422890 (DOI)2-s2.0-85051418678 (Scopus ID)9781538631805 (ISBN)
Conference
2018 IEEE International Conference on Communications, ICC 2018, 20 May 2018 through 24 May 2018
Note

Conference code: 138282; Export Date: 30 October 2018; Conference Paper; Funding text: This study is supported by EU Celtic Plus Project SooGREEN Service Oriented Optimization of Green Mobile Networks.

QC 20190114

Available from: 2019-01-14 Created: 2019-01-14 Last updated: 2019-01-14Bibliographically approved
Masoudi, M., Azari, A., Yavuz, E. A. & Cavdar, C. (2018). Grant-free Radio Access IoT Networks:Scalability Analysis in Coexistence Scenarios. In: : . Paper presented at IEEE ICC 2018.
Open this publication in new window or tab >>Grant-free Radio Access IoT Networks:Scalability Analysis in Coexistence Scenarios
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

IoT networks with grant-free radio access, likeSigFox and LoRa, offer low-cost durable communications overunlicensed band. These networks are becoming more and morepopular due to the ever-increasing need for ultra durable, interms of battery lifetime, IoT networks. Most studies evaluatethe system performance assuming single radio access technologydeployment. In this paper, we study the impact of coexistingcompeting radio access technologies on the system performance.Considering K technologies, defined by time and frequencyactivity factors, bandwidth, and power, which share a set of radioresources, we derive closed-form expressions for the successfultransmission probability, expected battery lifetime, and experienceddelay as a function of distance to the serving access point.Our analytical model, which is validated by simulation results,provides a tool to evaluate the coexistence scenarios and analyzehow introduction of a new coexisting technology may degrade thesystem performance in terms of success probability and batterylifetime. We further investigate solutions in which this destructiveeffect could be compensated, e.g., by densifying the network toa certain extent and utilizing joint reception.

Keywords
battery lifetime, IoT, LoRa, LPWA network, interference modelling.
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-232215 (URN)
Conference
IEEE ICC 2018
Note

QC 20180716

Available from: 2018-07-15 Created: 2018-07-15 Last updated: 2018-07-16Bibliographically approved
Vondra, M., Ozger, M., Schupke, D. & Cavdar, C. (2018). Integration of Satellite and Aerial Communications for Heterogeneous Flying Vehicles. IEEE Network, 32(5), 62-69
Open this publication in new window or tab >>Integration of Satellite and Aerial Communications for Heterogeneous Flying Vehicles
2018 (English)In: IEEE Network, ISSN 0890-8044, E-ISSN 1558-156X, Vol. 32, no 5, p. 62-69Article in journal (Refereed) Published
Abstract [en]

The rising number of airplanes and UAVs requiring connectivity in the sky puts high demands on all types of networks. In areas without DA2GC coverage, such as sea or oceans, the only option is SC. However, the capacity of SC is limited and insufficient in some cases. Therefore, an extension of DA2GC by A2AC and integration of A2AC and SC is a promising solution to improve available capacity. The main aim of this article is to evaluate limits of SC and A2AC in terms of maximum available capacity and maximum range. The results show that A2AC through DA2GC backhauling is able to overcome capacity available by SC on certain conditions while flying close to the mainland. Integration of A2AC and SC can significantly improve data rate available for UAVs and airplanes, especially if the sky cannot be covered by DA2GC only. Our results show that A2AC can provide capacity up to 93 Mb/s, and it can even exceed the capacity of SC when DA2GC and A2AC distances are short. When SC is overloaded, A2AC can be used instead to provide airplanes with capacity of 37 Mb/s up to 432 km DA2GC distance and 340 km A2AC distance. Besides the evaluation of both networks, the article also summarizes and discusses potential challenges and open issues of integration that need to be considered on the way to successful cooperation of both networks.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-237138 (URN)10.1109/MNET.2018.1800055 (DOI)000446529900010 ()2-s2.0-85054408481 (Scopus ID)
Note

QC 20181025

Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2019-08-20Bibliographically approved
Azari, A. & Cavdar, C. (2018). Performance Evaluation and Optimization of LPWA IoT Networks: A Stochastic Geometry Approach. In: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings: . Paper presented at 2018 IEEE Global Communications Conference, GLOBECOM 2018; Abu Dhabi National Exhibition Centre (ADNEC)Abu Dhabi; United Arab Emirates; 9 December 2018 through 13 December 2018. IEEE, Article ID 8647881.
Open this publication in new window or tab >>Performance Evaluation and Optimization of LPWA IoT Networks: A Stochastic Geometry Approach
2018 (English)In: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, IEEE, 2018, article id 8647881Conference paper, Published paper (Refereed)
Abstract [en]

Leveraging grant-free radio access for enabling low-power wide-area (LPWA) Internet of Things (IoT) connectivity has attracted lots of attention in recent years. Regarding lack of research on LPWA IoT networks, this work is devoted to reliability modeling, battery-lifetime analysis, and operation-control of such networks. We derive the interplay amongst density of the access points, communication bandwidth, volume of traffic from heterogeneous sources, and quality of service (QoS) in communications. The presented analytical framework comprises modeling of interference from heterogeneous sources with correlated deployment locations and time-frequency asynchronous radio-resource usage patterns. The derived expressions represent the operation regions and rates in which, energy and cost resources of devices and the access network, respectively, could be traded to achieve a given level of QoS in communications. For example, our expressions indicate the expected increase in QoS by increasing number of transmitted replicas, transmit power, density of the access points, and communication bandwidth. Our results further shed light on scalability of such networks and figure out the bounds up to which, scaling resources can compensate the increase in traffic volume and QoS demand. Finally, we present an energy-optimized operation control policy for IoT devices. The simulation results confirm tightness of the derived analytical expressions, and indicate usefulness of them in planning and operation control of IoT networks.

Place, publisher, year, edition, pages
IEEE, 2018
Series
IEEE Global Communications Conference, ISSN 2334-0983
Keywords
5G, Coexistence, Grant-free, Reliability and durability, LPWA IoT, نسل پنجم، اینترنت اشیا، قابلیت اطمینان، همزیستی، اتصال بدون رزرو منبع
National Category
Telecommunications
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-232213 (URN)10.1109/GLOCOM.2018.8647881 (DOI)000465774304097 ()2-s2.0-85063453911 (Scopus ID)978-1-5386-4727-1 (ISBN)
Conference
2018 IEEE Global Communications Conference, GLOBECOM 2018; Abu Dhabi National Exhibition Centre (ADNEC)Abu Dhabi; United Arab Emirates; 9 December 2018 through 13 December 2018
Note

QC 20180716

Available from: 2018-07-15 Created: 2018-07-15 Last updated: 2019-06-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0525-4491

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