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Symposium, 2005 Wireless Telecommunications

Date April 28-30, 2005

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Displaying Results 1 - 25 of 53
  • Peak-to-average power ratio analysis of multi-carrier pulse shape synthesis

    Publication Year: 2005, Page(s):136 - 142
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (342 KB) | HTML iconHTML

    MC (multi-carrier) pulse shape synthesis and decomposition offers significant BER performance gains when compared with traditional OFDM (orthogonal frequency division multiplexing) and SC (single-carrier) systems. How-even there is no prior work that characterizes and quantifies the PAPR performance of MC pulse shape synthesis. This paper addresses that issue. We compare the PAPR of MC pulse shape... View full abstract»

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  • Mobile network voice transmission quality estimation based on radio path parameters

    Publication Year: 2005, Page(s):95 - 99
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (246 KB) | HTML iconHTML

    The article describes design, development and test results of a voice transmission quality estimating algorithm that offers results (MOS estimates) comparable to intrusive speech quality measurements but which employs different techniques-analyzing radio path parameters only. The goal of this approach is to achieve relevant results faster, easier and with a lower computational power. However, the ... View full abstract»

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  • Wireless load sharing with heterogeneous services and adaptive placement

    Publication Year: 2005, Page(s):79 - 84
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (313 KB) | HTML iconHTML

    Load sharing between wireless networks can lead to increased performance and flexibility in network engineering. This simulation study demonstrates the performance of load sharing diverse services (circuit- and packet-oriented services) across heterogeneous wireless networks, when the flexibility rate, network size, and queue size for packet services varies. The simulation is verified using a Gaus... View full abstract»

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  • Dynamic admission control and QoS for 802.16 wireless MAN

    Publication Year: 2005, Page(s):60 - 66
    Cited by:  Papers (38)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB) | HTML iconHTML

    IEEE 802.16 wireless MAN is expected to revolutionize of the broadband wireless access technology. The grant/request mechanism in IEEE 802.16 MAC provides different quality of service (QoS) for different service flows. In the paper, we discuss the QoS issue in IEEE 802.16 wireless MANs and propose an admission control scheme for services defined in the 802.16 specifications. Our proposed scheme pr... View full abstract»

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  • Performance analysis of asynchronous carrier interferometry/MC-CDMA uplink with interference cancellation techniques

    Publication Year: 2005, Page(s):131 - 135
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (274 KB) | HTML iconHTML

    In this paper, we analyze the uplink performance of an asynchronous carrier interferometry/MC-CDMA, with nonlinear parallel and serial interference cancellation techniques. Specifically, we employ the new variant of parallel interference cancellation known as block-PIC and demonstrate significant performance (10 dB) improvement relative to conventional PIC. We also study the effect of order of can... View full abstract»

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  • Robust frequency offset estimation with a single symbol for FH-OFDMA

    Publication Year: 2005, Page(s):149 - 154
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (273 KB) | HTML iconHTML

    An initial carrier frequency offset estimation algorithm is proposed for a multi-user frequency hopping orthogonal frequency division modulation-frequency division multiple access (FH-OFDMA) system with a single preamble symbol. Since a multi-user OFDMA system is sensitive to carrier frequency offset which causes interferences among users, data loaded in subcarriers are easily damaged by the frequ... View full abstract»

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  • Improving the radio link layer QoS performance for Bluetooth real-time video communications

    Publication Year: 2005, Page(s):106 - 111
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (285 KB) | HTML iconHTML

    This paper investigates the quality of service (QoS) performance over a Bluetooth radio link for real-time video communications. A bit error control algorithm is proposed for protecting the bit error sensitive data of the latest video codecs as well as the compressed protocol headers. Bit errors and erroneous PDU delivery are analyzed in a Bluetooth link. UDP-Lite and robust protocol header compre... View full abstract»

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  • Simulations of site diversity based outage improvements for point-to-multipoint systems in millimeter-wave band

    Publication Year: 2005, Page(s):91 - 94
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (214 KB) | HTML iconHTML

    Rain attenuation is one of the main factors limiting performance of point-to-multipoint systems operating in millimeter-wave bands. Site diversity can be used as one of the propagation impairment mitigation techniques thanks to the non-uniform spatial distribution of the rain rate. A diversity gain concept is usually used for diversity evaluations. The motivation to this work is to offer to servic... View full abstract»

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  • On the reliability-aware geographic routing

    Publication Year: 2005, Page(s):74 - 78
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (203 KB) | HTML iconHTML

    Reliable communication is achieved when most reliable route is chosen from source to destination in ad hoc networks. The design of efficient routing protocols for dynamically changing network topologies is a crucial part of building power-efficient and scalable ad hoc wireless networks. If position information is available due to GPS or some kind of relative positioning technique, a promising appr... View full abstract»

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  • Novel pilot-free adaptive modulation for wireless OFDM systems

    Publication Year: 2005, Page(s):55 - 59
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (249 KB) | HTML iconHTML

    Orthogonal frequency division multiplexing (OFDM) is the contemporary technology adopted for digital audio/video broadcasting as well as wireless local-area and metropolitan-area networks. Since the wireless multimedia services often have different quality-of-service requirements and their performance is sensitive to the channel conditions, the conventional fixed OFDM modulation scheme might not b... View full abstract»

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  • Instant messaging usage policies enable ubiquitous communication

    Publication Year: 2005, Page(s):45 - 48
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (227 KB) | HTML iconHTML

    Instant messaging (IM) systems are popular among users. Inside corporate environments, the real-time nature of IM communication has resulted in increased productivity. However, network administrators are concerned about the lack of security in ubiquitous IM systems and their potential to leak sensitive data to outsiders. In response, some corporate managers have banned the use of IM inside the org... View full abstract»

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  • Cellular survivability: mobile PCS systems as scale free networks

    Publication Year: 2005, Page(s):246 - 252
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (350 KB) | HTML iconHTML

    The threat of catastrophic events on public utility systems is an ever-present threat. The survivability of wireless systems needs to be considered as they begin to play a greater role in voice communications. Reliably transmitting emergency calls is of particular importance. When a large cellular outage occurs, the network's ability to relay these calls decreases sharply, particularly in the affe... View full abstract»

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  • Bayesian parameter estimation for time and frequency synchronization

    Publication Year: 2005, Page(s):126 - 130
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (250 KB) | HTML iconHTML

    Bayesian estimation techniques are applied to the problem of time and frequency offset estimation for modern communications systems. The estimation technique employs Markov chain Monte Carlo (MCMC) to estimate unknown system parameters for a receiver with multiple antennae. A global parameter search is used to initialize time and frequency offsets. Tracking is achieved using a Metropolis-Hastings ... View full abstract»

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  • Lightweight packet authentication in IEEE 802.11

    Publication Year: 2005, Page(s):268 - 273
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB) | HTML iconHTML

    Due to the lack of security in IEEE 802.11b, IEEE 802.11i that can provide strong security is proposed. However, most users use WLAN (wireless local area networks) to do Web-surfing so that IEEE 802.11i has needless delays and computational overheads and even though the node authentication is performed in wireless domain between station (STA) and access point (AP) in IEEE 802.11, the malicious nod... View full abstract»

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  • ReWINS: a distributed multi-RF sensor control network for industrial automation

    Publication Year: 2005, Page(s):24 - 33
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (557 KB) | HTML iconHTML

    Remote "Monitor and Control" systems are being increasingly used in various areas including security, transportation, manufacturing, supply chain, healthcare, biomedical, etc. A unit system with hardware and software components, sans network support, for providing limited monitoring and control for industrial automation was proposed in our earlier work. In this paper, we extend that architecture t... View full abstract»

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  • A new service discovery architecture for sensor networks

    Publication Year: 2005, Page(s):190 - 196
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (287 KB) | HTML iconHTML

    Because wireless sensor networks (WSNs) as ad hoc networks allow devices to communicate dynamically without fixed infrastructure and centralized administration, they pose unique challenges on how informations collected by and stored within the network could be queried and accessed while saving devices power consumption. In this paper, we present a new distributed architecture for service location ... View full abstract»

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  • Monitoring and management solutions for 3G/4G wireless mobile networks

    Publication Year: 2005, Page(s):234 - 239
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (313 KB) | HTML iconHTML

    The complexity of the physical and logical structures of the 3/4G network and service environment demand more sophisticated and complicated tools to be fully controllable and well managed. One of the main problems is the traditional telemanagement model that does not suit for managing fast and constantly changing network and system environment. The present way using nonreal time off-line tools to ... View full abstract»

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  • Evaluation of the interference rejection capability of a uniform circular array in CDMA systems

    Publication Year: 2005, Page(s):143 - 148
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (243 KB) | HTML iconHTML

    The interference rejection capability of an antenna array at base station of a CDMA communications system results in improvement in the signal-to-interference ratio (SIR). In general, this figure of merit depends strongly on the array configuration and is a function of the direction of arrival of the desired signal, the number of antenna elements, and their spacing. In this paper, we consider a un... View full abstract»

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  • Speech-enabled mobile learning application

    Publication Year: 2005, Page(s):1 - 8
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (389 KB) | HTML iconHTML

    Mobile devices have recently gained global popularity for business and commercial uses like alerts and instant messaging. Yet, not much has been done to extend the usage of these devices in electronic learning. This paper explores the extension of e-learning into wireless/handheld (W/H) computing devices via speech-enabled discussion forum application. Discussion forums (or boards) are widely used... View full abstract»

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  • A sensitivity analysis approach to the optimal policy range of the resource access control in wireless systems

    Publication Year: 2005, Page(s):100 - 105
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (255 KB) | HTML iconHTML

    In this paper, the resource access control process is modelled as a Markov decision process. The stationary optimal resource access control policy is determined by solving the associated linear programming problem. Proposed resource access control policy allows employed system to make admission decisions to maximize system rewards according to current traffic condition and QoS metrics. The salient... View full abstract»

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  • Throughput analysis of a novel backoff algorithm for IEEE 802.11 WLANs

    Publication Year: 2005, Page(s):85 - 90
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (283 KB) | HTML iconHTML

    The IEEE 802.11 medium access control (MAC) adopts binary exponential backoff (BEB) to provide a contention-based channel access mechanism in the wireless medium. But many researches have shown that BEB may deteriorate the performance when the number of stations increases. In this paper, we propose a new contention window (CW) control algorithm called TB (Tender Backoff) which can tenderly adjust ... View full abstract»

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  • Asymptotic eigenvalue moments in large chip-synchronous CDMA

    Publication Year: 2005, Page(s):67 - 73
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (222 KB) | HTML iconHTML

    In this paper, the asymptotic eigenvalue distribution of the correlation matrix in a random spreading symbol-asynchronous but chip-synchronous CDMA system is studied. It is shown that, the asymptotic eigenvalue moments in a chip-synchronous system are equal to those of a symbol-synchronous system when the observation window is wider than a threshold. View full abstract»

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  • A novel statistical approach to ISI mitigation

    Publication Year: 2005, Page(s):155 - 161
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (271 KB) | HTML iconHTML

    Any communications signal suffers some degree of distortion during transmission. In high speed data communications, a significant portion of the distortion is ascribed to the presence of inter-symbol interference (ISI). Generally, an ISI channel can be modeled as a FIR filter. The ISI effect can thus be removed by inverse filtering the distorted signal at the receiver. The method presented in this... View full abstract»

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  • Data link control for multiple input multiple output wireless systems

    Publication Year: 2005, Page(s):112 - 119
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (361 KB) | HTML iconHTML

    This paper investigates the adaptation of data link error control protocols to be more efficient over MIMO wireless links. Data link mechanisms control, among other things, the transmission errors at the link layer, whereas MIMO is a physical layer technology that handles the wireless link with a notably high efficiency and flexibility. A new cross layer protocol is proposed in this paper in order... View full abstract»

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  • Cooperative MIMO gateways: a promising technique for fast handoff

    Publication Year: 2005, Page(s):49 - 54
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (302 KB) | HTML iconHTML

    The multi-input multi-output (MIMO) technique has been portrayed as the next revolution for wireless technologies. The MIMO technique is an effective mechanism to increase capacity and reliability of wireless communications by taking advantage of its spatial multiplexing gain or diversity gain. However, conventional MIMO is expensive: the form factor of the radio is large, multiple RF front ends a... View full abstract»

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