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Popescu, Alexandru
Publications (10 of 12) Show all publications
Popescu, A., Yao, Y., Fiedler, M. & Popescu, A. (2015). A Management Architecture for Multimedia Communication in Cognitive Radio Networks. In: Hu, F; Kumar, S (Ed.), Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments (pp. 3-31). CRC Press
Open this publication in new window or tab >>A Management Architecture for Multimedia Communication in Cognitive Radio Networks
2015 (English)In: Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments / [ed] Hu, F; Kumar, S, CRC Press, 2015, p. 3-31Chapter in book (Other academic)
Place, publisher, year, edition, pages
CRC Press, 2015
Series
MULTIMEDIA OVER COGNITIVE RADIO NETWORKS: ALGORITHMS, PROTOCOLS, AND EXPERIMENTS
National Category
Communication Systems
Identifiers
urn:nbn:se:bth-12635 (URN)000354055600002 ()978-1-4822-1487-1 (ISBN)
Available from: 2016-06-22 Created: 2016-06-22 Last updated: 2017-03-08Bibliographically approved
Yao, Y., Popescu, A. & Popescu, A. (2015). On prioritised opportunistic spectrum access in cognitive radio cellular networks. European transactions on telecommunications, 27(2), 294-310
Open this publication in new window or tab >>On prioritised opportunistic spectrum access in cognitive radio cellular networks
2015 (English)In: European transactions on telecommunications, ISSN 1124-318X, E-ISSN 2161-3915, Vol. 27, no 2, p. 294-310Article in journal (Refereed) Published
Abstract [en]

Cognitive radio (CR) networks allow secondary users (SUs) to opportunistically access licensed spectrum, thus providing efficient use of radio resources. Different studies carried out on CR networks have focused on the procedure of spectrum handoff of SUs such as the data transmission in a communication that can be carried out in different channels. In this paper, we consider cellular networks enhanced with facilities for CR communication where a user with a call in progress moves across neighbouring cells, that is, the so-called inter-cell handoff. Our model assumes that the cell gives priority to inter-cell handoff calls over the calls originating within it. A finite queue is used in every cell for SUs, and a fixed number of buffer slots are reserved for the inter-handoff SU calls. With these considerations, we study the transmission performance of SUs by using Markov chains-based modelling approach. The numerical analysis is validated by simulation experiments. We also suggest a fuzzy logic-based hybrid decision-making algorithm to select the best solution for inter-handoff prioritisation. The goal is to optimise the transmission performance of SUs by leveraging their requirements on service completion throughput and waiting time in each cell. Copyright © 2014 John Wiley & Sons, Ltd.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2015
Keywords
Cognitive radio, Opportunistic spectrum access, Cellular networks, Inter-cell handoff, Markov chain, Fuzzy logic
National Category
Telecommunications Probability Theory and Statistics
Identifiers
urn:nbn:se:bth-6581 (URN)10.1002/ett.2866 (DOI)000369856900009 ()oai:bth.se:forskinfo48345D93B679F058C1257D6D0050F49D (Local ID)oai:bth.se:forskinfo48345D93B679F058C1257D6D0050F49D (Archive number)oai:bth.se:forskinfo48345D93B679F058C1257D6D0050F49D (OAI)
Note

http://onlinelibrary.wiley.com/doi/10.1002/ett.2866/full

Available from: 2014-10-15 Created: 2014-10-10 Last updated: 2017-06-16Bibliographically approved
Popescu, A. (2014). Cognitive Radio Networks: Elements and Architectures. (Doctoral dissertation). Karlskrona: Blekinge Institute of Technology
Open this publication in new window or tab >>Cognitive Radio Networks: Elements and Architectures
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

As mobility and computing becomes ever more pervasive in society and business, the non-optimal use of radio resources has created many new challenges for telecommunication operators. Usage patterns of modern wireless handheld devices, such as smartphones and surfboards, have indicated that the signaling traffic generated is many times larger than at a traditional laptop. Furthermore, in spite of approaching theoretical limits by, e.g., the spectral efficiency improvements brought by 4G, this is still not sufficient for many practical applications demanded by end users. Essentially, users located at the edge of a cell cannot achieve the high data throughputs promised by 4G specifications. Worst yet, the Quality of Service bottlenecks in 4G networks are expected to become a major issue over the next years given the rapid growth of mobile devices. The main problems are because of rigid mobile systems architectures with limited possibilities to reconfigure terminals and base stations depending on spectrum availability. Consequently, new solutions must be developed that coexist with legacy infrastructures and more importantly improve upon them to enable flexibility in the modes of operation. To control the intelligence required for such modes of operation, cognitive radio technology is a key concept suggested to be part of the so-called beyond 4th generation mobile networks. The basic idea is to allow unlicensed users access to licensed spectrum, under the condition that the interference perceived by the licensed users is minimal. This can be achieved with the help of devices capable of accurately sensing the spectrum occupancy, learning about temporarily unused frequency bands and able to reconfigure their transmission parameters in such a way that the spectral opportunities can be effectively exploited. Accordingly, this indicates the need for a more flexible and dynamic allocation of the spectrum resources, which requires a new approach to cognitive radio network management. Subsequently, a novel architecture designed at the application layer is suggested to manage communication in cognitive radio networks. The goal is to improve the performance in a cognitive radio network by sensing, learning, optimization and adaptation.

Place, publisher, year, edition, pages
Karlskrona: Blekinge Institute of Technology, 2014. p. 204
Series
Blekinge Institute of Technology Doctoral Dissertation Series, ISSN 1653-2090 ; 2
Keywords
Cognitive radio network management, spectrum access, multiconstrained routing optimization, multi-dimensional adaptation, middleware
National Category
Telecommunications Computer Sciences
Identifiers
urn:nbn:se:bth-00575 (URN)oai:bth.se:forskinfo40F87A2722691197C1257C460052509D (Local ID)978-91-7295-272-0 (ISBN)oai:bth.se:forskinfo40F87A2722691197C1257C460052509D (Archive number)oai:bth.se:forskinfo40F87A2722691197C1257C460052509D (OAI)
Available from: 2014-04-10 Created: 2013-12-19 Last updated: 2018-01-11Bibliographically approved
Popescu, A., Yao, Y., Fiedler, M. & Popescu, A. (2014). Network Architecture to Support Multimedia over CRN. In: Hu, Fei; Kumar, Sunil (Ed.), Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments. CRC Press
Open this publication in new window or tab >>Network Architecture to Support Multimedia over CRN
2014 (English)In: Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments / [ed] Hu, Fei; Kumar, Sunil, CRC Press , 2014Chapter in book (Refereed)
Place, publisher, year, edition, pages
CRC Press, 2014
National Category
Telecommunications Computer Sciences
Identifiers
urn:nbn:se:bth-6570 (URN)oai:bth.se:forskinfo4F47C3D977B8CD5CC1257D8F004DE38C (Local ID)9781482214857 (ISBN)oai:bth.se:forskinfo4F47C3D977B8CD5CC1257D8F004DE38C (Archive number)oai:bth.se:forskinfo4F47C3D977B8CD5CC1257D8F004DE38C (OAI)
Note

http://www.crcpress.com/product/isbn/9781482214857

Available from: 2014-11-14 Created: 2014-11-13 Last updated: 2018-01-11Bibliographically approved
Yao, Y., Popescu, A. & Popescu, A. (2014). On Fuzzy Logic-Based Channel Selection in Cognitive Radio Networks. In: Kaabouch, Naima; Hu, Wen-Chen (Ed.), Software-Defined and Cognitive Radio Technologies for Dynamic Spectrum Management: . Hershey, PA 17033, USA: IGI-Global
Open this publication in new window or tab >>On Fuzzy Logic-Based Channel Selection in Cognitive Radio Networks
2014 (English)In: Software-Defined and Cognitive Radio Technologies for Dynamic Spectrum Management / [ed] Kaabouch, Naima; Hu, Wen-Chen, Hershey, PA 17033, USA: IGI-Global , 2014Chapter in book (Refereed)
Abstract [en]

Cognitive radio networks are a new technology based on which unlicensed users are allowed access to licensed spectrum under the condition that the interference perceived by licensed users is minimal. That means unlicensed users need to learn from environmental changes and to take appropriate decisions regarding the access to the radio channel. This is a process that can be done by unlicensed users in a cooperative or non-cooperative way. Whereas the non-cooperative algorithms are risky with regard to performance, the cooperative algorithms have the capability to provide better performance. Our paper reports therefore a new fuzzy logic based decision making algorithm for channel selection. The underlying decision criterion considers statistics of licensed users channel occupancy as well as information about the competition level of unlicensed users. Our theoretical studies indicate that the unlicensed users can obtain an efficient sharing of the available channels. Simulation results are reported to demonstrate the performance and effectiveness of the suggested algorithm.

Place, publisher, year, edition, pages
Hershey, PA 17033, USA: IGI-Global, 2014
Keywords
Cognitive radio, channel selection, fuzzy logic, idle time, competition
National Category
Mathematics Telecommunications Computer Sciences
Identifiers
urn:nbn:se:bth-6470 (URN)10.4018/978-1-4666-6571-2 (DOI)oai:bth.se:forskinfo2812FB81D416739CC1257DB3003B760A (Local ID)9781466665712 (ISBN)oai:bth.se:forskinfo2812FB81D416739CC1257DB3003B760A (Archive number)oai:bth.se:forskinfo2812FB81D416739CC1257DB3003B760A (OAI)
Note

Book link: http://www.igi-global.com/book/handbook-research-software-defined-cognitive/1100 09?camid=3v11 Book ToC link: http://www.igi-global.com/Files/Ancillary/93ec3b2d-fd60-4a53-9118-c0975308400b_T OC.pdf

Available from: 2014-12-30 Created: 2014-12-19 Last updated: 2018-01-11Bibliographically approved
Popescu, A., Yao, Y., Fiedler, M. & Popescu, A. (2013). Communication Mechanisms for Cognitive Radio Networks. In: : . Paper presented at Pervasive Computing and Communication (PerCom). San Diego, USA: IEEE Press
Open this publication in new window or tab >>Communication Mechanisms for Cognitive Radio Networks
2013 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Comprehensive communication in cognitive radio networks is an important research topic within the scope of empowering cognitive radio functionality in beyond-4G mobile networks. Providing communication for secondary users without interference with primary users is an ambitious task, which requires innovative management architecture designs and routing solutions. Operational challenges such as opportunistic spectrum access, solving problems related to spectrum and network heterogeneities and requests for the provisioning of Quality-of-Service to different applications must be resolved. As part of a novel management architecture, the paper advances a new approach to end-to-end communication in cognitive radio networks based on combining ad-hoc algorithms with spectrum mobility algorithms.

Place, publisher, year, edition, pages
San Diego, USA: IEEE Press, 2013
Keywords
routing, constraint optimization, communication mechanisms, spectrum access
National Category
Computer Sciences
Identifiers
urn:nbn:se:bth-6795 (URN)10.1109/PerComW.2013.6529536 (DOI)000325178400091 ()oai:bth.se:forskinfo6951825BBD88BE6DC1257BC7002D3267 (Local ID)978-1-4673-5076-1 (ISBN)oai:bth.se:forskinfo6951825BBD88BE6DC1257BC7002D3267 (Archive number)oai:bth.se:forskinfo6951825BBD88BE6DC1257BC7002D3267 (OAI)
External cooperation:
Conference
Pervasive Computing and Communication (PerCom)
Available from: 2013-12-19 Created: 2013-08-14 Last updated: 2018-01-11Bibliographically approved
Popescu, A., Yao, Y. & Fiedler, M. (2013). On Mobility Generated Signaling in Cognitive Radio Network Clusters. In: : . Paper presented at Global Wireless Summit (GWS). Atlantic City, USA: IEEE Press
Open this publication in new window or tab >>On Mobility Generated Signaling in Cognitive Radio Network Clusters
2013 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The rapid migration towards wireless connectivity means that the radio spectrum must be efficiently utilized to conserve capacity and to avoid overcrowding, particularly in densely populated areas. Towards this goal, cognitive radio technology is a key concept. The basic idea is to allow unlicensed users access to licensed spectrum, under the condition that the interference perceived by the licensed users is minimal. A novel architecture designed and developed at the application layer has been suggested by researchers at Blekinge Institute of Technology for the management of cognitive radio networks. Emphasizing on signaling facilities in this architecture and common control channel dimensioning aspects, the paper reports on simulation results regarding node mobility for a particular network model. To reduce the energy consumption of mobile devices, innovative signaling strategies are a very important topic to consider in novel mobile system architectures.

Place, publisher, year, edition, pages
Atlantic City, USA: IEEE Press, 2013
Keywords
Cognitive radio network management, signaling, random waypoint mobility, routing, middleware
National Category
Computer Sciences
Identifiers
urn:nbn:se:bth-6660 (URN)000332186700072 ()oai:bth.se:forskinfoF6CF2DCC76E368B7C1257BC7002E63C0 (Local ID)oai:bth.se:forskinfoF6CF2DCC76E368B7C1257BC7002E63C0 (Archive number)oai:bth.se:forskinfoF6CF2DCC76E368B7C1257BC7002E63C0 (OAI)
External cooperation:
Conference
Global Wireless Summit (GWS)
Available from: 2014-07-17 Created: 2013-08-14 Last updated: 2018-01-11Bibliographically approved
Yao, Y., Popescu, A., Ngoga, S. R. & Popescu, A. (2013). On Prioritized Spectrum Access in Cognitive Radio Networks with Imperfect Sensing. In: : . Paper presented at Wireless Personal Multimedia Communications Symposium (WPMC'13). Atlantic City: VPMC/IEEE
Open this publication in new window or tab >>On Prioritized Spectrum Access in Cognitive Radio Networks with Imperfect Sensing
2013 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Cognitive Radio networks allow the unlicensed users to share the available spectrum opportunities. However, this demands for solving the problem of contention among multiple unlicensed user packets for transmission. In our paper, we consider the Opportunistic Spectrum Access model for packet transmission between two unlicensed users. We suggest a priority scheme for a unlicensed user to concurrently transmit different types of packets. Our scheme reserves a fixed number of queueing places in the buffer for the prioritized packets. We study the transmission performance under both the priority scheme and imperfect spectrum sensing, with respect to the blocking probabilities, average transmission delay and transmission throughput of unlicensed users packets. The Markov chain based numerical analysis is validated by simulation experiments. Our results show that the suggested priority scheme is able to enhance transmission throughput of unlicensed users packets, together with significant decreased average transmission delay and minor decreased total transmission throughput.

Place, publisher, year, edition, pages
Atlantic City: VPMC/IEEE, 2013
Keywords
Cognitive radio, opportunistic spectrum access, priority scheme, Markov chain
National Category
Telecommunications Computer Sciences
Identifiers
urn:nbn:se:bth-6658 (URN)000332186700073 ()oai:bth.se:forskinfo3A71EEBE07889ABDC1257B8A0045797B (Local ID)oai:bth.se:forskinfo3A71EEBE07889ABDC1257B8A0045797B (Archive number)oai:bth.se:forskinfo3A71EEBE07889ABDC1257B8A0045797B (OAI)
Conference
Wireless Personal Multimedia Communications Symposium (WPMC'13)
Note

Global Wireless Summit

Available from: 2014-07-17 Created: 2013-06-14 Last updated: 2018-01-11Bibliographically approved
Martinez-Bauset, J., Popescu, A., Pla, V. & Popescu, A. (2012). Cognitive Radio Networks with Elastic Traffic. In: : . Paper presented at Eighth Euro-NF Conference on Next Generation Internet (NGI). Karlskrona
Open this publication in new window or tab >>Cognitive Radio Networks with Elastic Traffic
2012 (English)Conference paper, Published paper (Refereed)
Abstract [en]

We model and evaluate an infrastructure based cognitive radio network where impatient unlicensed or secondary users (SUs) offer elastic traffic. The interference created by SUs to the licensed users is analyzed when the secondary network uses two different spectrum access schemes, the conventional random access scheme and a new scheme we refer to as access with preference. To further control the interference, a limit is set to the number of channels SUs have access to. With this new constraint, the abandonment probability, the mean delay and throughput of the SUs degrades significantly. To improve the QoS perceived by the active SUs, we define and evaluate an admission control scheme for the SUs.

Place, publisher, year, edition, pages
Karlskrona: , 2012
Keywords
Cognitive radio networks, spectrum access, elastic traffic, performance evaluation
National Category
Computer Sciences Telecommunications
Identifiers
urn:nbn:se:bth-7298 (URN)oai:bth.se:forskinfo5A708F715915D794C12579F800384860 (Local ID)oai:bth.se:forskinfo5A708F715915D794C12579F800384860 (Archive number)oai:bth.se:forskinfo5A708F715915D794C12579F800384860 (OAI)
External cooperation:
Conference
Eighth Euro-NF Conference on Next Generation Internet (NGI)
Available from: 2012-09-18 Created: 2012-05-08 Last updated: 2018-01-11Bibliographically approved
Popescu, A. & Fiedler, M. (2012). On Data Representation in Cognitive Radio Networks. In: : . Paper presented at Swedish National Computer Networking Workshop. Stockholm: Swedish Institute for Computer Science
Open this publication in new window or tab >>On Data Representation in Cognitive Radio Networks
2012 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Dynamic Spectrum Access (DSA) and routing in Cognitive Radio Networks (CRNs) present challenging operational and technological problems in beyond 4G networks. Additionally, the provision of Quality of Experience (QoE) for different applications and Cognitive Radio Devices (CRDs) requires new management architectures and knowledge information approaches. The paper advances a new data-representation solution to allow efficient multi-constraint routing and multi dimensional adaptation for multiple cognitive radio (CR) dimensions like space, frequency, power and time. The goal of the paper is to advance a system for CRN data representation, which allows optimized communication according to QoE demands between Secondary Users (SUs).

Place, publisher, year, edition, pages
Stockholm: Swedish Institute for Computer Science, 2012
Keywords
Cognitive Radio Networks Management Architecture, Data Representation, Dynamic Spectrum Access, Quality of Experience
National Category
Telecommunications Computer Sciences
Identifiers
urn:nbn:se:bth-7264 (URN)oai:bth.se:forskinfo082C41ACA06A7F85C1257A5B002F8D8A (Local ID)oai:bth.se:forskinfo082C41ACA06A7F85C1257A5B002F8D8A (Archive number)oai:bth.se:forskinfo082C41ACA06A7F85C1257A5B002F8D8A (OAI)
External cooperation:
Conference
Swedish National Computer Networking Workshop
Available from: 2012-09-18 Created: 2012-08-15 Last updated: 2018-01-11Bibliographically approved
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