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Communications, 2009. ICC '09. IEEE International Conference on

Date 14-18 June 2009

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Displaying Results 1 - 25 of 1038
  • ICC 2009 - Title page

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

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  • ICC 2009 Greetings from the General Chair

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  • ICC 2009 Greetings from the TPC Chair

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  • ICC 2009 Patrons

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  • ICC 2009 Organizing Committee

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  • ICC 2009 IEEE Communications Society

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  • ICC 2009 Schedule at a glance

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  • ICC 2009 Techincal Symposia

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  • 2nd Order Cyclostationarity of OFDM Signals: Impact of Pilot Tones and Cyclic Prefix

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (822 KB) |  | HTML iconHTML  

    This paper deals with 2nd order cyclostationarity of orthogonal frequency division multiplex (OFDM) signals. A new generalized formula for the spectral correlation density (SCD) function is derived. Compared to related work in the literature, our derivation is not restricted to the case that all sub-carriers of an OFDM signal carry statistically independent data. The reason for that is that correlated data in terms of pilot tones are typically introduced on different carriers for channel estimation and synchronization purposes. The new formula allows us to analyze the impact of such pilot tones on the SCD. In addition, it gives extra information about the impact of the cyclic prefix. View full abstract»

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  • 3G/HSPA Performance in Live Networks from the End User Perspective

    Publication Year: 2009 , Page(s): 1 - 6
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (547 KB) |  | HTML iconHTML  

    Operators around the world are improving their 3G/UMTS networks by introducing HSPA (High Speed Packet Access) that includes both, enhanced uplink and downlink. The HSPA is expected to finally provide the mobile broadband access that is able to compete with the fixed connections in performance regarding popular applications such as Web browsing, VoIP, and video. However, it has remained unclear how well the live networks fulfill the promises of performance. We contribute in filling this void by providing measurements in live 3G/HSPA networks. We compare TCP and UDP good-put performance in basic WCDMA, HSDPA-only, and HSPA. Moreover, one-way delay and jitter measurement results are presented in a stationary as well as in a mobile scenario. The results show that the enhanced network outperforms clearly its predecessor by offering considerably higher data rates, lower delay, and lower jitter. Also, because of the HARQ (Hybrid Automatic Repeat request), there are notably less delay spikes observed with HSPA than with WCDMA. However, the drive tests show that handovers result in high jitter and interruptions to the communications, which causes, e.g., decreased VoIP call quality. The uplink enhancement (HSUPA) improves the TCP performance beyond the HSDPA-only access, but it is still behind that of the fixed connections. In addition, the properties of the channel allocation mechanism still considerably deteriorate the data rates seen by the user. Nevertheless, the HSPA is an enabler for true mobile broadband internet access. View full abstract»

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  • A 3-D Markov Chain Queueing Model of IEEE 802.11 DCF with Finite Buffer and Load

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (173 KB) |  | HTML iconHTML  

    We introduce a 3-dimensional Markov chain that integrates the IEEE 802.11 DCF contention resolution and queueing processes into one model. Important QoS measures, delay and loss, plus throughput and queue length, can be obtained for a realistic systems with finite buffer under finite load. We present an efficient method for solving the steady state probabilities of the Markov chain. Simulations confirm the accuracy of our model, and demonstrate that the model provides new insights into the 802.11 DCF protocol. View full abstract»

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  • A Behaviour Study of Network-Aware Stealthy Worms

    Publication Year: 2009 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (185 KB) |  | HTML iconHTML  

    This paper examines the general behaviour of stealthy worms. In particular, we focus on worms that are designed based on network awareness. We study the case where a worm, instead of aiming to spread as fast as possible and penetrate intrusion detection systems (IDS), aims to avoid IDS and spread with the minimum number of detections. We compare different scanning strategies for this worm, including different combinations of hitlist and random scanning, and how they affect the number of infections and the rate of detected infection attempts. We compare the network-aware worm's behavior to that of the Code Red II worm. Simulations show that scanning worms can generate many fewer detections using localized scanning while maintaining its capability to infect. View full abstract»

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  • A Blind Channel Estimation Algorithm for Space-Time Coded MC-CDMA Receivers

    Publication Year: 2009 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (241 KB) |  | HTML iconHTML  

    In this paper we proposed a linearly constrained minimum variance receiver for a space-time coded multicarrier (MC) CDMA system in frequency selective fading channels. It is shown that in the proposed receiver the channel can be blindly estimated as the eigenvector that corresponds to the maximum eigenvalue of an autocorrelation matrix, and then, efficient algorithms for subspace tracking can be used. Computer simulations shows that the proposed channel estimation algorithm achieves performance comparable to traditional algorithms with less computational cost. View full abstract»

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  • A Body Surface Coordinator for Implanted Biosensor Networks

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    Biomedical sensors can be implanted and networked in the human body for health monitor, diagnosis, treatment or as a prosthetic device. Life time and heat generated by implant due to communication and circuitry power consumption are big concerns. This paper presents a new network architecture for long range communications in the implanted sensor networks. We measured the on-body propagation around body surface and in-body propagation through tissue in the frequency ranges of 403 MHz and 2.45 GHz. We have found that the in-body path loss is more than that of on-body. To exploit the path loss difference, we propose to introduce a body surface coordinator which has more resources to the implanted sensor networks. Instead of only routing data among implants, the coordinator on the body surface can forward data from one implant to another over long distance more safely and efficiently. View full abstract»

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  • A Case Study for Evaluating IEEE 802.15.4 Wireless Sensor Network Formation with Mobile Sinks

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1015 KB) |  | HTML iconHTML  

    Wireless Sensor Networks are traditionally composed of a multiplicity of sensor nodes that sense given phenomena and deliver the sensed data to specific sink nodes. In the most of the application scenarios, sensor nodes have been considered motionless. On the contrary, interesting possibilities arise if some sensors are embedded in devices carried by mobile agents as people, cars, animals, etc. If sinks move within the considered sensor field, they are able to provide both sparse sensing and collecting of data measured by static sensors placed at fixed locations. The main goal of this work is to evaluate, through simulations, the impact of sinks' mobility in a wireless sensor network created by using the topology formation mechanism provided by the IEEE 802.15.4 Standard. To this aim, as a practical case study, we consider a wireless sensor network deployed in a museum used to monitor the presence, the localization and other parameters of artworks exposed in it. In this context, we analyze how sinks' mobility affects connectivity and energy consumption for network formation and re-configuration. View full abstract»

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  • A Chaotic Maps-Based Key Agreement Protocol that Preserves User Anonymity

    Publication Year: 2009 , Page(s): 1 - 6
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (181 KB) |  | HTML iconHTML  

    A key agreement protocol is a protocol whereby two or more communicating parties can agree on a key or exchange information over an open communication network in such a way that both of them agree on the established session keys for use in subsequent communications. Recently, several key agreement protocols based on chaotic maps are proposed. These protocols require a verification table to verify the legitimacy of a user. Since this approach clearly incurs the risk of tampering and the cost of managing the table and suffers from the stolen-verifier attack, we propose a novel key agreement protocol based on chaotic maps to enhance the security. The proposed protocol not only achieves mutual authentication without verification tables, but also allows users to anonymously interact with the server. Moreover, security of the proposed protocol is modelled and analyzed with Petri nets. Our analysis shows that the proposed protocol can successfully defend replay attacks, forgery attacks, and stolen-verifier attacks. View full abstract»

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  • A Combined Approach for Receiver-Based MAC and Network Layers in Wireless Sensor Networks

    Publication Year: 2009 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    Data communication represents the greatest energy cost of wireless sensor networks. Both MAC and network layers of the protocol stack are responsible for data communication in these networks. This work proposes the Receiver- based Medium Access Control (Rb-MAC) protocol to be used in a combined solution with a receiver-based routing scheme. The main advantage of combining receiver-based MAC and routing protocols is that this solution does not use neighbor tables and, consequently, it saves energy when compared with MAC and routing protocols that use these tables. Simulation results reveal that receiver-based data communication has a great data delivery ratio, and reduces energy consumption, number of transmissions, and collisions when compared with a sender-based data communication. Moreover, we use a model checking technique to perform the formal verification of Rb-MAC. View full abstract»

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  • A Comprehensive Analytical Model for Weighted Fair Queuing under Multi-Class Self-Similar Traffic

    Publication Year: 2009 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (169 KB) |  | HTML iconHTML  

    Weighted fair queueing (WFQ) is a practical scheduling discipline for supporting differentiated quality-of-service (QoS) in computer networks and communication systems. Analytical models are important tools for system performance evaluation and resource optimization. However, there is not any comprehensive model reported in the open literature for analytically investigating the performance behaviors of WFQ subject to multiple self-similar traffic flows. To fill this gap, this paper develops such a model and derives the upper bounds for the distributions of several important QoS performance metrics including queue length, packet delay and loss of traffic flows in the WFQ system. The comparison between analytical and simulation results using the traffic parameters obtained from real-world MPEG frame traces validates the accuracy of the developed model which can be used for investigating the performance behavior of WFQ systems with multi-class self- similar traffic under realistic working conditions. View full abstract»

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  • A Compressed Sensing Based Ultra-Wideband Communication System

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (17)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (275 KB) |  | HTML iconHTML  

    Sampling is the bottleneck for ultra-wideband (UWB) communication. Our major contribution is to exploit the channel itself as part of compressed sensing, through waveform-based pre-coding at the transmitter. We also have demonstrated a UWB system baseband bandwidth (5 GHz) that would, if with the conventional sampling technology, take decades for the industry to reach. The concept has been demonstrated, through simulations, using real-world measurements. Realistic channel estimation is also considered. View full abstract»

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  • A Cooperative Scheme for Dynamic Window Resizing in P2P Live Streaming

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (130 KB) |  | HTML iconHTML  

    Due to their widespread popularity, peer-to-peer (P2P) live streaming systems have become a great challenge for Internet service providers (ISPs) as they consume huge amount of Internet bandwidth. By observing that different users may watch a channel with different window sizes, we propose a cooperative scheme called partial participation scheme (PPS) in which different peers request a video stream at different rates based on their window sizes, and a subset of peers viewing the video stream using a small window work as helpers to forward extra data to help other peers using a large window. By reducing streaming rate received by small-window peers, the total amount of consumed bandwidth decreases without sacrificing users' satisfaction. PPS includes peer cooperative bandwidth allocation algorithms and neighbor maintenance mechanisms to achieve short resizing delay when a peer changes its window between different sizes. We evaluate the performance of PPS via a comprehensive set of metrics generated from extensive simulations. Our simulation results show that PPS greatly reduces the bandwidth consumption, achieves short resizing delay, and maintains high and stable streaming quality. View full abstract»

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  • A Cooperative Vehicular Network Framework

    Publication Year: 2009 , Page(s): 1 - 6
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB) |  | HTML iconHTML  

    Vehicular Ad Hoc Networks are networks characterized by intermittent connectivity and rapid changes in their topology. This paper addresses car-to-road communications in which vehicles use Access Points (AP) in a Delay Tolerant Network architecture. Results show how the combination of a Delay-Cooperative ARQ mechanism reduces packet losses and in conjunction with a Carry-and-Forward cooperative mechanism improves performance parameters in terms of total file transfer delay and number of AP needed to download files. View full abstract»

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  • A Cross Layer Fast Handover Scheme in VANET

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB) |  | HTML iconHTML  

    This study presents a cross-layer fast handover scheme for VANET, called vehicular fast handover scheme (VFHS), where the physical layer information is shared with the MAC layer, to reduce the handover delay. The key idea of VFHS is to utilize oncoming side vehicles (OSVs) to collect physical and MAC layers information of passing through RVs and broadcast the information to vehicles that are temporarily disconnected, referred to as broken vehicles (BVs). A BV can thus perform a rapid handover when it enters the transmission range of the approaching RVs. The effectiveness of VFHS is verified using ns2 simulations. Simulation results indicate that VFHS significantly decreases handover latency and packet loss. View full abstract»

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  • A Cross-Layer Perspective on Rateless Coding for Wireless Channels

    Publication Year: 2009 , Page(s): 1 - 6
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (250 KB) |  | HTML iconHTML  

    Rateless coding ensures reliability by providing ever-increasing redundancy, traditionally at the packet level (i.e. the application layer) through erasure coding. This paper explores whether additional redundancy for wireless channels is most helpful at the packet level through erasure coding or at the physical layer through lower-rate channel coding. This cross-layer trade-off is explored in a traditional wireless setting where the communication of a message consisting of a fixed number of packets takes place over a Rayleigh fading channel. The examined scenarios include both a single receiver and multiple cooperating receivers allowing the results to be extended to situations where selection diversity is available in the system. For several interesting scenarios, this paper determines the optimal trade-off between the amount of packet-level erasure coding and physical-layer channel coding required to provide reliable communication over the widest range of operating SNR's. Our results indicate that packet-level erasure coding can provide a significant benefit when no other form of diversity is available. In many cases, the amount of redundancy that should be allocated to such erasure coding is nearly constant, and further redundancy (i.e. any rateless coding) should be applied to the physical layer. View full abstract»

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  • A Data-Aided Symbol Timing Estimation Algorithm for OFDM/OQAM Systems

    Publication Year: 2009 , Page(s): 1 - 5
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    In this paper we deal with the problem of data- aided symbol timing estimation for orthogonal frequency division multiplexing systems based on offset-QAM modulation (OFDM/OQAM). Specifically, a data-aided joint phase offset and symbol timing estimator, based on the least squares (LS) approach, exploiting the conjugate-symmetry property of a properly designed training symbol, is derived. Since the phase estimate is in closed form, the symbol timing estimate requires only an one-dimensional maximization procedure. The derived LS estimator does not require the knowledge of the prototype filter and, moreover, its performance, is independent of the carrier frequency offset. View full abstract»

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