- 0046708556338
Adrian Popescu
Blekinge Institute of Technology, School of Computing (COM), Faculty Member
- Professor emeritusedit
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
CONVINcE is a CELTIC-PLUS project dedicated to minimizing the power consumption in IP-based video distribution networks, from the headend to the terminal. The entire video distribution chain is considered in the project, covering a wide... more
CONVINcE is a CELTIC-PLUS project dedicated to minimizing the power consumption in IP-based video distribution networks, from the headend to the terminal. The entire video distribution chain is considered in the project, covering a wide range of entities involved in this process. Examples of these entities are headend, edge cloud, Content Distribution Network (CDN), core backbone network, Radio Access Network (RAN) as well as fixed and mobile terminals. Related to this, one of the most difficult research questions is regarding the provision of minimum end-to-end power consumption for video streams combined with the best possible Quality of Experience (QoE) obtained at the terminal. It requires solving a number of sophisticated research questions, among them modelling and optimization problems. The paper first provides an overview of video distribution networks, which is followed by a short presentation of the CONVINcE project. The second part is focused on the optimization concept s...
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The demand for live and interactive multimedia services over the Internet raises questions on how well the Internet Protocol (IP)’s best-effort effort service can be adapted to provide adequate end-to-end quality of service (QoS) for the... more
The demand for live and interactive multimedia services over the Internet raises questions on how well the Internet Protocol (IP)’s best-effort effort service can be adapted to provide adequate end-to-end quality of service (QoS) for the users. Although the Internet community has developed two different IP-based QoS architectures, neither has been widely deployed. Overlay networks are seen as a step to address the demand for end-to-end QoS until a better solution can be obtained. As part of the telecommunication research at Blekinge Institute of Technology (BTH) in Karlskrona, Sweden we are investigating new theories and algorithms concerning QoS routing. We are in the process of developing Overlay Routing Protocol (ORP), a framework for overlay QoS routing consisting of two protocols: Route Discovery Protocol (RDP) and Route Management Protocol (RMP). In this paper we describe RDP and provide preliminary simulation results for it.
Research Interests:
This chapter is to appear in the forthcoming Performance Handboook “Next Generation Internet: Performance Evaluation and Applications”, edited by the Demetres D. Kouvatsos and to be published by Springer.
The demand for live and interactive multimedia services over the Internet raises questions on how well the Internet Protocol (IP)s best-effort effort service can be adapted to provide adequate end-to-end quality of service (QoS) for the... more
The demand for live and interactive multimedia services over the Internet raises questions on how well the Internet Protocol (IP)s best-effort effort service can be adapted to provide adequate end-to-end quality of service (QoS) for the users. Although the Internet community has developed two different IP-based QoS architectures, neither has been widely deployed. Overlay networks are seen as a step to address the demand for end-to-end QoS until a better solution can be obtained. As part of the telecommunication research at Blekinge Institute of Technology (BTH) in Karlskrona, Sweden we are investigating new theories and algorithms concerning QoS routing. We are in the process of developing Overlay Routing Protocol (ORP), a framework for overlay QoS routing consisting of two protocols: Route Discovery Protocol (RDP) and Route Management Protocol (RMP). In this paper we describe RDP and provide preliminary simulation results for it.
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
... Systems, Technology and Management, University of New South Wales aybuke@unsw.edu.au 3 School of Management, Blekinge Institute of Technology anders.hederstierna@bth.se Abstract. ... Utility theory looks at net wealth, where prospect... more
... Systems, Technology and Management, University of New South Wales aybuke@unsw.edu.au 3 School of Management, Blekinge Institute of Technology anders.hederstierna@bth.se Abstract. ... Utility theory looks at net wealth, where prospect theory considers gains and losses. ...
In recent years, Internet has known an unprecedented growth, which, in turn, has lead to an increased demand for real-time and multimedia applications that have high Quality-of-Service (QoS) demands. This evolution lead to difficult... more
In recent years, Internet has known an unprecedented growth, which, in turn, has lead to an increased demand for real-time and multimedia applications that have high Quality-of-Service (QoS) demands. This evolution lead to difficult challenges for the Internet Service Providers (ISPs) to provide good QoS for their clients as well as for the ability to provide differentiated service subscriptions for those clients who are willing to pay more for value added services. Furthermore, a tremendous development of several types of overlay ...
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Most of the research in spectrum sharing has neglected the effect of interference from primary users. In this reported work, the performance of spectrum sharing amplify-and-forward relay networks under interference-limited environment,... more
Most of the research in spectrum sharing has neglected the effect of interference from primary users. In this reported work, the performance of spectrum sharing amplify-and-forward relay networks under interference-limited environment, where the interference induced by the transmission of primary networks is taken into account, is investigated. In particular, a closed-form expression tight lower bound of outage probability is derived. To reveal additional insights into the effect of primary networks on the diversity and array ...
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In cognitive radio networks, unlicensed users need to learn from environmental changes. This is a process that can be done in a cooperative or non-cooperative manner. Due to the competition for channel utilization among unlicensed users,... more
In cognitive radio networks, unlicensed users need to learn from environmental changes. This is a process that can be done in a cooperative or non-cooperative manner. Due to the competition for channel utilization among unlicensed users, the non-cooperative approach may lead to overcrowding in the available channels. This paper is about a fuzzy logic based decision making algorithm for competition-based channel selection. The underlying decision criterion integrates both the statistics of licensed users' channel ...
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Research Interests:
A novel measurement system is reported for delay measurements in IP routers, which follows specifica-tions of the IETF RFC 2679. The system employs both passive measurements and active probing and offers the possibility to measure and... more
A novel measurement system is reported for delay measurements in IP routers, which follows specifica-tions of the IETF RFC 2679. The system employs both passive measurements and active probing and offers the possibility to measure and analyze the One-Way Transit ...
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ABSTRACT In this paper we describe our simulation models for evaluating end-to-end performance of HTTP transactions. We first analyze several gigabytes of collected traffic traces from a production Frame Relay network. Using these traces... more
ABSTRACT In this paper we describe our simulation models for evaluating end-to-end performance of HTTP transactions. We first analyze several gigabytes of collected traffic traces from a production Frame Relay network. Using these traces we extract web traffic and analyze the server web pages accessed by actual users. We analyze over 25000 web pages and develop a web client/server interaction model based upon our analysis of many server contents. We make specific contributions by analyzing the popularity of web servers and the number of bytes transferred from them during a busy hour. We also compute the distribution of the number of embedded items within a web document. We then use these models to drive a network simulation and show the interactions between the TCP/IP flow control and retransmission mechanism on source parameters. One of our important contributions has been to show that the Hurst parameter is robust with regard to TCP/IP flow and error control. Using the simulation studies we show that the distribution of end-to-end application message delay has a heavy-tail distribution and we discuss how these distributions arise in the network context.
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The paper reports on a performance study of several Application Layer Multicast (ALM) protocols. Three categories of overlay multicast networks are investigated, namely Application Level Multicast Infrastructure (ALMI), Narada and NICE is... more
The paper reports on a performance study of several Application Layer Multicast (ALM) protocols. Three categories of overlay multicast networks are investigated, namely Application Level Multicast Infrastructure (ALMI), Narada and NICE is the Internet Cooperative Environment (NICE). The performance of the overlay multicast protocols is evaluated with reference to a set of performance metrics that capture both application and network level performance. The study focuses on the control overhead induced by the protocols under study. This further relates to the scalability of the protocol with increasing number of multicast participants. In order to get a better assessment of the operation of these protocols in "real-life"-like conditions, we implemented in our simulations a heavy-tailed delay at the network level and churn behavior of the overlay nodes. Our performance study contributes to a deeper understanding and better assessment of the requirements for such protocols tar...
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This paper presents an overview of the implementation of Application Layer Multicast (ALM) in OverSim, a simulation framework designed specifically for simulating overlay networks. OverSim builds upon the OMNeT++ discrete event simulator.... more
This paper presents an overview of the implementation of Application Layer Multicast (ALM) in OverSim, a simulation framework designed specifically for simulating overlay networks. OverSim builds upon the OMNeT++ discrete event simulator. In addition, the paper presents guidelines for further research work based on reliable and Quality of Service (QoS)-aware multicast overlay networks. This research work is part of a bigger research project, called "Routing in Overlay Networks (ROVER)" which is focused on unicast and multicast routing in overlay networks with QoS guarantees and congestion control facilities on top of existing and future Peer-to-Peer (P2P) networks.
Research Interests:
Research Interests:
The emergence of new types of popular multimedia services requires in the long run a quality-of-service (QoS) solution better than the best-effort service provided by IP. Failure to widely deploy either one of the main architectures for... more
The emergence of new types of popular multimedia services requires in the long run a quality-of-service (QoS) solution better than the best-effort service provided by IP. Failure to widely deploy either one of the main architectures for IP QoS, integrated services (IntServ) or differentiated services (DiffServ), has fueled research into alternate solutions based on overlay networks on top of IP. At Blekinge Institute of Technology (BTH) we are working towards an architecture for multimedia distribution in overlay networks. An important part of this architecture is QoS overlay routing. This paper discusses Overlay Routing protocol (ORP), a framework for unicast overlay routing, which will be used to test various QoS routing protocols and algorithms.
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Overlay networks are networks operating on the inter-domain level, where the edge hosts learn of each other and, based on knowledge of underlying network performance, they form loosely coupled neighboring relationships. These... more
Overlay networks are networks operating on the inter-domain level, where the edge hosts learn of each other and, based on knowledge of underlying network performance, they form loosely coupled neighboring relationships. These relationships can be used to induce a specific graph, where nodes are representing hosts and edges are representing neighboring relationships. Graph abstraction and the associated graph theory can be further used to formulate routing algorithms on overlay networks. The main advantage of overlay networks is that they offer the possibility to augment the IP routing as well as the QoS functionality offered by the Internet.
Research Interests:
This chapter is to appear in the forthcoming Performance Handboook “Next Generation Internet: Performance Evaluation and Applications”, edited by the Demetres D. Kouvatsos and to be published by Springer.
Quality of Service (QoS) is a difficult term to define for multimedia applications. The main reason is that both audio and video quality are subjective and difficult to quantify. Much work has been done in the past to map the subjective... more
Quality of Service (QoS) is a difficult term to define for multimedia applications. The main reason is that both audio and video quality are subjective and difficult to quantify. Much work has been done in the past to map the subjective quality of video and audio into measurable quantities. Unfortunately, when it comes to IP environments, not much experience and mathematical work exists that can be used to define robust metrics for measurement of QoS. In this paper, we report on measurements of multimedia QoS and try to map subjective criteria to discrete measurables in terms of packet loss rates, packet delays, and other quantities. We report the results of measurements done at the application level and show how network characteristics affect the perceived quality of multimedia applications. In particular, we analyze the application traffic generated by MBone clients in a distributed network education scenario. In order to measure the traffic, we have implemented software on a non-...
This document is a review of basic concepts in traffic self-similarity. It is about definitions of self-similarity, key properties, measurements, models, generation of synthetic traces, revealing of specific properties in self-similar... more
This document is a review of basic concepts in traffic self-similarity. It is about definitions of self-similarity, key properties, measurements, models, generation of synthetic traces, revealing of specific properties in self-similar teletraffic, origins as well as performance impacts. The material is standard and can be used for a first course in Traffic Self-Similarity at the senior/graduate level.
Cognitive radio technology is a key concept suggested to be part of the so-called 5th generation mobile networks. The basic idea is to allow unlicensed users access to licensed spectrum, under the condition that the interference perceived... more
Cognitive radio technology is a key concept suggested to be part of the so-called 5th 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. An important aspect is the need to develop highly specialized and efficient management mechanisms to control the dynamic spectrum access of cognitive radio. Accordingly, operational challenges related to opportunistic spectrum access, spectrum and network heterogeneities and requests for the provision of diverse Quality-of-Service to different applications in a multimedia communication must be resolved. The chapter advances a new architecture for the management of cognitive radio networks, designed and developed at the application layer. Particular focus is laid on common control channel and dimensioning aspects with performance evaluation reported for the basic scenario.