B. Ciubotaru

Dublin City University, Dublin, Leinster, Ireland

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Publications (10)4.17 Total impact

  • Yang Song, B. Ciubotaru, G.-M. Muntean
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    ABSTRACT: This paper introduces a novel quality-oriented cross-layer energy-efficient data communication solution (Q-PASTE) for mobile devices, with two components at different network layers. First component, the Packet/ApplicaTion manager (PAT) is deployed at the application layer of both service gateway and client host. The gateway level PAT shapes traffic into bursts to reduce the wireless transceiver's duty cycle. The client-side PAT monitors each active session and informs the Medium Access Control (MAC) layer about their traffic-related behavior. The second component, the Slow sTart Exponential and Linear Algorithm (STELA), deployed at MAC layer, adaptively adjusts the sleep/wake-up behavior of mobile device wireless interfaces in order to reduce energy consumption while also maintaining high Quality of Service (QoS) levels. Both mathematical analysis and simulation-based modeling and testing have been performed to evaluate Q-PASTE performance. Comparative results have shown significant energy saving achieved when using Q-PASTE, without compromising content delivery performance.
    Communications Workshops (ICC), 2013 IEEE International Conference on; 01/2013
  • Yang Song, B. Ciubotaru, G.-M. Muntean
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    ABSTRACT: This paper introduces a novel Medium Access Control (MAC) strategy for energy efficient wireless data transmissions which reduces energy consumption while minimizing the negative impact on network Quality of Service (QoS). This strategy adaptively adjusts the sleeping window of the mobile devices' wireless transceiver. The proposed mechanism - the Slow sTart Exponential and Linear Algorithm (STELA) - consists of three sleeping window adaptation phases, each phase employing a different duty cycle management function. Based on analyzing historic data regarding traffic arrival patterns, traffic modeling is used to estimate future patterns. Consequently, the specific adaptation phases are scheduled and tuned to improve energy efficiency without compromising data delivery performance. Simulation-based testing results show significant energy savings with reduced impact on network QoS achieved when STELA is used, as opposed to other existing MAC layer protocols (IEEE 802.11 and IEEE 802.16) considered in this paper for performance comparisons.
    Local Computer Networks (LCN), 2012 IEEE 37th Conference on; 01/2012
  • Yang Song, Bogdan Ciubotaru, Gabriel-Miro Muntean
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    ABSTRACT: Limited battery capacity seriously restricts the usage of wireless devices in wireless communication networks. Power saving MAC layer protocols put wireless network interface into sleep mode in order to conserve energy. However, increased energy savings may sacrifice delivery performance and consequently the user perceived Quality of Service (QoS). This paper introduces Slow-sTart Exponential and Linear Algorithm (STELA), a novel battery saving mechanism which saves up to 70% energy compared with the algorithms employed by IEEE 802.11 while preventing the delivery performance from degrading significantly and consequently reducing the negative impact on user Quality of Experience (QoE).
    01/2011;
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    Bogdan Ciubotaru, Gabriel-Miro Muntean
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    ABSTRACT: Handover management becomes an increasingly important component of the emergent mobile Internet by maintaining mobile user's data sessions alive in the presence of user mobility. The great impact handover has on Quality of Service makes it a crucial factor in maintaining mobile user's Quality of Experience at a high level. This paper evaluates the Quality of Multimedia Streaming metric proposed by the authors in a previous paper. Quality of Multimedia Streaming is a comprehensive and flexible metric for estimating the amount of traffic each network can hold. Unlike the traditional handover algorithms which select the best network, the investigated solution estimates the capacity of each network and dynamically distributes the application traffic over the available networks accordingly. The simulation-based evaluation outlines the performance of the proposed metric and evaluates its parameters for best performance in term of user Quality of Experience.
    The 35th Annual IEEE Conference on Local Computer Networks, LCN 2010, 10-14 October 2010, Denver, Colorado, USA, Proceedings; 01/2010
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    B. Ciubotaru, G.-M. Muntean, G. Ghinea
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    ABSTRACT: Adaptive multimedia streaming relies on controlled adjustment of content bitrate and consequent video quality variation in order to meet the bandwidth constraints of the communication link used for content delivery to the end-user. The values of the easy to measure network-related Quality of Service metrics have no direct relationship with the way moving images are perceived by the human viewer. Consequently variations in the video stream bitrate are not clearly linked to similar variation in the user perceived quality. This is especially true if some human visual system-based adaptation techniques are employed. As research has shown, there are certain image regions in each frame of a video sequence on which the users are more interested than in the others. This paper presents the Region of Interest-based Adaptive Scheme (ROIAS) which adjusts differently the regions within each frame of the streamed multimedia content based on the user interest in them. ROIAS is presented and discussed in terms of the adjustment algorithms employed and their impact on the human perceived video quality. Comparisons with existing approaches, including a constant quality adaptation scheme across the whole frame area, are performed employing two objective metrics which estimate user perceived video quality.
    IEEE Transactions on Broadcasting 07/2009; · 2.09 Impact Factor
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    B. Ciubotaru, G.-M. Muntean
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    ABSTRACT: The convergence of the existing network access technologies to a common IP-based architecture and the increase in popularity of accessing video content over the Internet makes IPTV a promising solution for media and entertainment industries. Additionally, video content delivery to the increasingly popular mobile devices over heterogeneous wireless networks makes IPTV even more appealing. However the distribution of multimedia content over heterogeneous wireless networks to mobile devices involves significant technical challenges related to mobility management and quality of service provisioning. The existing solutions do not consider quality of service as a decision making parameter for mobility management in general and handover management in particular. This paper proposes the smooth adaptive soft handover algorithm (SASHA), a novel quality-aware approach to handover based on load balancing among different networks using a comprehensive, quality of multimedia streaming (QMS), function for decision making. SASHA represents the handover management solution at the core of the more comprehensive multimedia mobility management system (M3S), a quality oriented mobility management framework for multimedia applications which maximizes user perceived quality by efficiently exploiting all available communication resources. Simulation-based testing results are presented, outlining the performance of SASHA in different mobility scenarios. The evaluation is performed for different number of nodes performing handover simultaneous and for various situations in terms of networks' overlapping area. The results shown indicate how SASHA outperforms other three mobility management solutions in terms of quality, scalability and resilience to the dynamics of the networks' overlapping area.
    IEEE Transactions on Broadcasting 07/2009; · 2.09 Impact Factor
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    B. Ciubotaru, G.-M. Muntean
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    ABSTRACT: Mobility has become a mandatory feature of the future Internet as mobile computing gains increasing popularity among Internet users. The rapidly evolving heterogeneous wireless environment provides a variety of communication resources for the mobile host. In order to fully benefit of these wireless access networks an efficient and quality oriented mobility management system has to be employed. This paper presents an innovative solution for handover management based on an estimation of multimedia streaming quality which considers both quality of service and user quality of experience in the decision making process. The proposed solution aims at improving the user perceived quality in the context of mobile multimedia streaming by efficiently exploiting all the communication resources available to the mobile host. Simulation-based performance evaluation shows the performance improvement, both in quality of service and user perceived quality, when the proposed solution is used compared to other mobility solutions.
    Broadband Multimedia Systems and Broadcasting, 2009. BMSB '09. IEEE International Symposium on; 06/2009
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    B. Ciubotaru, G.-M. Muntean
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    ABSTRACT: Inter-network mobility is achieved by allowing a mobile node to change its point of attachment to the network while preserving connectivity to its corresponding nodes. Most handover solutions proposed in the literature directly change the whole data flow from one network to another relying on only one network to transfer the entire data stream. These solutions involve a certain amount of quality degradation due to increasing loss and delay and suffer in terms of scalability, efficient resource allocation and resilience to different mobile node speeds. This paper proposes the smooth adaptive soft-handover algorithm (SASHA) which increases the quality of the multimedia delivery process when performing handover in heterogeneous wireless environment by gracefully transferring the load from one connection to the other.
    Wireless Communications and Networking Conference, 2009. WCNC 2009. IEEE; 05/2009
  • Bogdan Ciubotaru, Gabriel-Miro Muntean
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    ABSTRACT: Inter-network mobility is achieved by allowing a mobile node to change its point of attachment to the network while preserving connectivity to its corresponding nodes. Most handover solutions proposed in the literature directly change the whole data flow from one network to another relying on only one network to transfer the entire data stream. These solutions involve a certain amount of quality degradation due to increasing loss and delay and suffer in terms of scalability, efficient resource allocation and resilience to different mobile node speeds. This paper proposes the Smooth Adaptive Soft-Handover Algorithm (SASHA) which increases the quality of the multimedia delivery process when performing handover in heterogeneous wireless environment by gracefully transferring the load from one connection to the other.
    Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference; 04/2009
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    Bogdan Ciubotaru, Gabriel-Miro Muntean
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    ABSTRACT: Wireless local-area networks represent a viable broadband Internet access solution for enterprise, residential and public areas. Due to its short range radio, multiple wireless access points are necessary to cover a certain physical area. The tendency of mobile users to group in certain areas of interest and of mobile devices to connect to the access point with the highest signal strength determines the overall network load to be highly unbalanced. To overcome this issues which drastically affects user bandwidth share as well as the efficiency of network resource utilization, special load balancing techniques has to be employed. This paper presents the Multimedia Mobility Management System (M3S), a quality oriented mobility management framework which aims at maximizing user perceived multimedia quality by efficiently distributing the traffic load over all the communication resources available. Simulation based testing results are presented, outlining the performance of M3S against other load balancing techniques which rely on mobile device re-association with least congested access points.