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Communication Networks and Services Research Conference, 2009. CNSR '09. Seventh Annual

Date 11-13 May 2009

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  • [Front cover]

    Publication Year: 2009 , Page(s): C1
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  • [Title page i]

    Publication Year: 2009 , Page(s): i
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  • [Title page iii]

    Publication Year: 2009 , Page(s): iii
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  • [Copyright notice]

    Publication Year: 2009
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  • Table of contents

    Publication Year: 2009 , Page(s): v - xi
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  • Message from the Conference General Co-chairs

    Publication Year: 2009 , Page(s): xii
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  • Preface

    Publication Year: 2009 , Page(s): xiii
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  • Organizing Committee

    Publication Year: 2009 , Page(s): xiv - xvii
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  • list-reviewer

    Publication Year: 2009 , Page(s): xviii - xxiii
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  • Keynote 1

    Publication Year: 2009 , Page(s): xxiv - xxv
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB) |  | HTML iconHTML  

    The explosive growth of information technology (IT) and communications infrastructures, coupled with the diversity of their components and a shortage of skilled IT workers, have resulted in systems whose control and timely management exceeds human ability. Current IT management solutions are costly, ineffective, insecure and labor intensive. autonomic computing (AC) models IT infrastructures and their applications as closed-loop control systems that need to be continuously monitored, analyzed followed by corrective actions whenever any of the desired behavior properties (e.g., performance, fault, security) are violated. Such AC techniques are inspired by strategies used by biological systems to deal with complexity, dynamism, heterogeneity and uncertainty. The design space for designing AC systems spans multiple disciplines such as distributed computing, virtualization, control theory, artificial intelligence, statistics, software architectures, mathematical programming, and networking. Our research efforts will accelerate the research and development of core autonomic technologies and services. In this presentation, I will give an overview of UA autonomic computing projects and focus on two projects: Autonomia: An autonomic control and management environment, and AND: autonomic network defense system. View full abstract»

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  • Keynote 2

    Publication Year: 2009 , Page(s): xxvi - xxvii
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    In the early days of wireless communications the research community used to view multipath-induced dispersion as an undesirable propagation phenomenon, which could only be combatted with the aid of complex channel equalizers. The longer the Channel Impulse Response (CIR) was, the more complex the channel equalizer became. However, provided that the complexity of a sufficiently high-memory channel equalizer was affordable, the receiver could benefit from the fact that the individual propagation paths faded independently. To elaborate a little further, even if one of the paths was experiencing a high attenuation, there was a good chance that some of the other paths were not, which led to a potential diversity gain. However, if the channel does not exhibit several independently fading paths, techniques of artificially inducing diversity may have to be sought. A simple option is to employ a higher direct-sequence spreading factor, which results in a higher number of resolvable multipath components and hence in an increased diversity gain. Naturally, this is only possible if either the available bandwidth may be extended according to the spreading factor or the achievable bitrate is reduced by the same factor. A whole host of classic diversity combining techniques may be invoked then for recovering the original signal. As a design alternative, we commence by classifying the different multiple-input multiple-output (MIMO) schemes while considering the attainable diversity gains, multiplexing gains and beamforming gains. Following a brief classification of different MIMO schemes, where the different MIMO schemes are categorised as diversity techniques, multiplexing schemes, multiple access arrangements and beamforming techniques, we introduce the family of multi-functional MIMOs. These multi-functional MIMOs are capable of combining the benefits of several MIMO schemes and hence attaining an improved performance in terms of both their bit error ratio (BER) as well as thro- ghput. The multifunctional MIMOs family combines the benefits of space-time coding, Bell labs layered space-time scheme as well as beamforming. We also introduce the idea of layered steered space-time spreading that combines the benefits of space-time spreading, V-BLAST and beamforming with those of the generalised multi-carrier direct sequence code division multiple access. Additionally, we compare the attainable diversity, multiplexing and beamforming gains of the different MIMO schemes in order to document the advantages of the multi-functional MIMOs over conventional MIMO schemes. However, in the presence of shadow-fading the now classic co-located MIMO elements are incapable of providing multiple independently faded replicas of the transmitted signal. This problem may be corcumvented by employing relaying, distributed space-time coding or some other cooperation-aided procedure, which is the subject of this lecture. One could also view the benefits of decode-and-forward based relaying as receiving and then flawlessly regenerating and re-transmitting the original transmitted signal from a relay - provided of course that the relay succeeded in error-freely detecting the original transmitted signal. This lecture reviews the current state-of-the-art and proposes a number of novel relaying and cooperation techniques. An important related issue is the availability or the absence accurate channel information, which leads to the concept of coherent versus non-coherent detection at the relays and at the destination. Similarly, the related initial synchronization issues also have to be considered. Naturally, when using hard-decisions in the transmission chain, we discard valuable soft-information, which results in an eroded performance, albeit also reduces the complexity imposed. Hence the hard- versus soft-decoding performance trade-off will also be explored in the lecture, along with the benefits of interleaved random space-time coding invoked for multi-source cooperat View full abstract»

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  • Keynote 3

    Publication Year: 2009 , Page(s): xxviii - xxix
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (85 KB) |  | HTML iconHTML  

    Summary form only given. Explosion of data and mass availability of Internet connections around the globe had created huge bandwidth requirements for bandwidth hungry applications. Despite the technological advances in the core and their ability to transport, still much work has to be done in the access networks in order to be able to let the broadband traffic be transmitted transparently. Current solutions for access networks do not provide a concrete solution for the famous last mile problem. In this talk we will present passive optical access networks as well as broadband wireless access networks as viable solutions to the ongoing problems in the broadband access networks. Further we will cover physical and technological limitations with the current state-of-the-art technology. We will address the optical as well as wireless broadband access networks promises in responding to these shortcomings. We will focus on passive optical networks (PONs), reviewing different type of PONs considering their benefits and limitations. We will also present an overview of broadband wireless access networks, such as WiMAX. View full abstract»

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  • Tutorial 1 [breaker page]

    Publication Year: 2009 , Page(s): xxx
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  • Tutorial 2 [breaker page]

    Publication Year: 2009 , Page(s): xxxi - xxxii
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  • Semiblind Multiuser MIMO Channel Estimators Using PM and RRQR Methods

    Publication Year: 2009 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (513 KB) |  | HTML iconHTML  

    Estimating the channel state information (CSI) of several transmitters that use orthogonal space-time block codes (OSTBC) to communicate with a single receiver is considered. Based on rank revealing QR (RRQR) factorization and propagator method (PM), two new algorithms to estimate multiuser MIMO channels are proposed. The algorithm estimates the subspace spanned by the user channels use only a few training blocks to extract the users CSI from this subspace. Our both algorithms achieve better performance in comparison with reference LS based approach. Computer simulations are included to validate proposed methods. View full abstract»

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  • WiMAX Network Optimization - Analyzing Effects of Adaptive Modulation and Coding Schemes Used in Conjunction with ARQ and HARQ

    Publication Year: 2009 , Page(s): 6 - 13
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    The flexibility of WiMAX framework offers new dimensions for cross-layer optimization and can be exploited to optimize the application performance. This article focuses on identifiers that have direct impact on quality of service (QoS)and effect of such identifiers is evaluated through computer simulation using OPNET Modeler 14.5 Wireless Suite. In this paper we have used advanced WiMAX features such as adaptive modulation and coding (AMC), automatic repeat request (ARQ) and hybrid-ARQ to tune the WiMAX network MAC layer such that its adaptation improves both capacity and delay (thus optimize the performance). ARQ is treated as higher layer to HARQ. HARQ gives up after maximum retransmissions. HARQ performs fast retransmissions and ARQ takes over in cases HARQ fails after multiple retransmissions. This gives an added layer of protection to data. HARQ is proved to be most suitable (when used with aggressive modulation and coding) for WiMAX due to its hybrid nature as it takes into account both the MAC and link layer. Using ARQ in conjunction with HARQ gives slight improvement in BLER (Block Error Rate) but at the expense of high UL frame utilization. View full abstract»

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  • Carrier Frequency Offset Mitigation in OFDM Systems Using Efficient Tone Reservation

    Publication Year: 2009 , Page(s): 14 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (257 KB) |  | HTML iconHTML  

    One of the major drawbacks of orthogonal frequency division multiplexing (OFDM) is sensitivity to carrier frequency offset (CFO) caused by a mismatch between the transmitter and receiver oscillators. CFO destroys the orthogonality of the subcarriers and introduces intercarrier interference (ICI), reducing the system performance. Previously, tone reservation (TR) was considered for reducing the peak interference-to-carrier ratio (PICR) and shown to provide significant PICR reduction. In this paper, we use submatrices of the inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) to reduce the number of variables in the optimization to efficiently compute the optimal tones. Performance results are presented which demonstrate that the proposed algorithm yields PICR performance similar to that with the previous TR technique. View full abstract»

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  • A Multi-channel QoS Model for Random Access Systems

    Publication Year: 2009 , Page(s): 20 - 24
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    In this paper, we present a simple two-class QoS model for random access systems. We provide a practical mechanism for categorizing the available resources into two distinct service classes prior to medium access. We use an a Markov chain model to define the states and transitions, and derive the system access success probability. This provides a mathematical basis for an accurate model that can be efficiently used to determine the resource allocation for each class. This model provides a useful analytical tool for contention systems that utilize random access for network entry, resource acquisition, and/or contention-based data transmission, e.g. the IEEE 802.16 uplink contention channel. We also study the trade-off between resources allocated and the input traffic from each class. For simplicity, we only consider two classes, however the technique can easily be extended to any number of classes. View full abstract»

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  • A Practical Survey of H.264 Capabilities

    Publication Year: 2009 , Page(s): 25 - 32
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (465 KB) |  | HTML iconHTML  

    H.264 is excellent for transmitting rich interactive media over narrow and broadband networks, and can be easily integrated into existing and future networks. Video compression efficiency is improved by at least a factor of two over the MPEG-2 standard. H.264 provides bit-rate adaptivity and scalability, which addresses the needs of different applications when transmitted over heterogeneous networks. This is also necessary for applications where the receiving device is not capable of displaying full resolution or full quality video images. This paper provides new insights into the key features of the H.264 based on actual experiments. It also illustrates how the strengths of different capabilities can be combined in a complementary fashion. Among the key attributes of H.264 that were tested include profile type, CABAC and CAVLC, RDO, and FMO error concealment. View full abstract»

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  • Video Streaming over 802.11b in the Presence of Fading Due to Human Traffic and Bluetooth Interference

    Publication Year: 2009 , Page(s): 33 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB) |  | HTML iconHTML  

    The performance of video streaming over 802.11b is evaluated through experimental measurements in the presence of fading caused by human traffic, distance and Bluetooth interference, which shares the same 2.4 GHz ISM band. A measurement network consisting of a desktop connected to the wired Internet at the University of New Brunswick (UNB), a wireless laptop and a Bluetooth smart phone were used for conducting all the measurements which were carried out at UNB within the D level of Head Hall. The received video signal quality was measured in terms of the clock jumps observed in the video showing a ticking analog clock. The results show a video capture range (VCR) for quality video streaming and a video lock range (VLR) where the video signal could not be acquired. The statistical results show significant negative effects of distance and human traffic on video streaming and received video quality. View full abstract»

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  • Measurement of MPEG-2 Video Streams through a Differentiated Service Domain

    Publication Year: 2009 , Page(s): 41 - 46
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (302 KB) |  | HTML iconHTML  

    There is growing popularity of real-time Internet traffic such as audio and video streams. Such traffic benefits from receiving a different level of service from the network than more traditional data traffic. Schemes for providing differing network service for different applications have been proposed under the name QoS (Quality of Service). We investigate the performance of one such scheme by using a testbed to transmit both video and data traffic. In this paper we report on measurement techniques used in the testbed to report on performance and describe several problems and their solution. View full abstract»

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  • Optical Access-Metro Network Architecture Based on Passive Access and Burst-Mode Transmission

    Publication Year: 2009 , Page(s): 47 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    A network architecture that integrates several WDM PON access segments in a metropolitan area network and uses optical circuit/burst switching is presented here. This architecture targets the delivery of very high speed end to end optical communications between the edge nodes connecting the end users. The combination of circuit switching and burst transmission allows the simultaneous delivery of real-time applications (VoIP, Video) and other data-oriented applications (Internet, peer-to-peer). In the proposed architecture there is a clear separation of the functions in data plane and a control plane. A centralized control entity manages the overall architecture. A dedicated aggregation node acts as a gateway to external networks. After a presentation of the proposed network architecture, this paper focuses on the performance evaluation of the control plane using simulation. Our results show that the queuing delay remains acceptable even under heavy traffic loads. View full abstract»

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  • Workload Characterization of a Large Systems Conference Web Server

    Publication Year: 2009 , Page(s): 55 - 64
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1026 KB) |  | HTML iconHTML  

    This paper presents a workload characterization study of the WWW2007 conference Web site. We use both server-sideband client-side measurement to collect data for our analysis. The collected datasets contain approximately 10 million requests from about 130,000 unique visitors generating 215 GB of traffic volume during a 1-year period. Our analysis focuses on usage behaviour, client errors, client network properties,bandwidth, and robot activity of the site.In addition to the workload characterization study itself,our work also offers a comparative discussion of different approaches to Web data analysis, and some insights for future organizers of large systems conferences with a significant Web presence. View full abstract»

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  • Packet Loss Probability Approximation in High-Speed Networks Based on Self-Similar Traffic

    Publication Year: 2009 , Page(s): 65 - 69
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    As the packet/cell loss ratio (PLR/CLR) is counted as one of the major quality of service (QoS) requirements; in this paper we proposed a linear upper bound expression for the loss probability approximation in high-speed communication network technologies. These technologies can support multiple classes of traffic with different QoS requirements and diverse traffic characteristics, by the use of traffic multiplexing. The proposed expression can be calculated in real-time, so it can be properly used in the network multiplexers. Based on the fact that in many cases, the real traffic in high-speed networks shows a self-similar behavior, we have used self-similar traffic with Pareto distribution as the input traffic model in our PLR approximation simulations. We have studied application of this expression in non-homogeneous as well as homogeneous cases. View full abstract»

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  • BotCop: An Online Botnet Traffic Classifier

    Publication Year: 2009 , Page(s): 70 - 77
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (491 KB) |  | HTML iconHTML  

    A botnet is a network of compromised computers infected with malicious code that can be controlled remotely under a common command and control (C&C) channel. As one the most serious security threats to the Internet, a botnet cannot only be implemented with existing network applications (e.g. IRC, HTTP, or Peer-to-Peer) but also can be constructed by unknown or creative applications, thus making the botnet detection a challenging problem. In this paper, we propose a new online botnet traffic classification system, called BotCop, in which the network traffic are fully classified into different application communities by using payload signatures and a novel decision tree model, and then on each obtained application community, the temporal-frequent characteristic of flows is studied and analyzed to differentiate the malicious communication traffic created by bots from normal traffic generated by human beings. We evaluate our approach with about 30 million flows collected over one day on a large-scale WiFi ISP network and results show that the proposed approach successfully detects an IRC botnet from about 30 million flows with a high detection rate and a low false alarm rate. View full abstract»

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