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3G and Beyond, 2005 6th IEE International Conference on

Date 7-9 Nov. 2005

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Displaying Results 1 - 25 of 95
  • MIMO-OFDM: Basic Relations between Coding, Spreading, Multicarrier and Singlecarrier Transmission

    Publication Year: 2005, Page(s): 1
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (59 KB)

    This contribution considers the basic relations between coding, spreading, multicarrier and singlecarrier transmission against the background of MIMO-OFDM. MIMO-OFDM is taken, because it can be regarded as a scheme which contains many others as special cases, and also because of its increasing relevance for future wireless communication. It is shown that spreading plays a central role: Spreading i... View full abstract»

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  • Exploitation of Diversity in MC-CDMA Systems

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1658 KB)

    MC-CDMA has an additional degree of freedom to exploit diversity compared to OFDMA or MC-TDMA due to spreading. This paper analyzes the achievable BER lower bounds for different MC-CDMA schemes exploiting channel state information (CSI) at the transmitter, the receiver, or both. Using channel knowledge at both sides is referred to as combined-equalization. Different design criteria for single-user... View full abstract»

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  • Adaptive MIMO-OFDM for Future Mobile Radio Communications

    Publication Year: 2005, Page(s):1 - 4
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (387 KB)

    This paper addresses the topic of bit and power loading in coded MIMO-OFDM systems. Due to the need of designing communication systems with high spectral efficiencies, the combination of multiple antennas at transmitter and receiver with OFDM represents a promising approach. Moreover, channel knowledge at the transmitter can be exploited to adapt the transmission to the channel. While loading stra... View full abstract»

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  • Exploiting Multiuser Diversity for MIMO Cellular Systems Using Packet Scheduling and the VBLAST Receiver

    Publication Year: 2005, Page(s):1 - 6
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2509 KB)

    Several packet scheduling techniques for the downlink of a multiple-input multiple-output (MIMO) cellular system are investigated. The system capacity for three scheduling are investigated. The system capacity for three scheduling algorithms, the conventional round robin scheduling (RRS) the antenna-assisted round robin (AA-RRS) and a novel VBLAST AA-RRS, are evaluated. Computer simulations are us... View full abstract»

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  • Evaluation of the Capacity of Multiple-Access MIMO Schemes with Feedback in a Small Outdoor Cell

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2583 KB)

    Three algorithms to exploit the multi-user MIMO channel are examined and their system capacity evaluated in the uplink of a small urban cell scenario using measured channel data. An iterative scheme to determine transmit weights that achieve the system-wide Nash Equilibrium (NE) is compared to schemes achieving block-diagonalization (BD) of the overall system channel matrix and successive diagonal... View full abstract»

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  • Heading Routing Protocols: Mobility-Based Routing for Ad-Hoc Networks

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3962 KB)

    In this paper, we present routing algorithms for mobile ad-hoc networks, which exploit the mobility patterns of nodes to provide a robust and long-lived route to destination and reduce flooding and overhead in the network. In the proposed protocols, only a small number of the network nodes are selected based on their Heading Direction Angle (HDA), to form a route from the source to the destination... View full abstract»

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  • Investigation of Energy Efficiency for Singlehop and Multihop Routing Shcemes in a Wireless Sensor Network

    Publication Year: 2005, Page(s):1 - 4
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4201 KB)

    Wireless sensor nodes run on small battery power and it is sometimes impossible to replace the batteries due to the environment and cost factors associated with them. Therefore, energy efficiency is a critical issue in the design and management of a wireless sensor network. In this paper, following the configuration and protocol implementation within a wireless sensor network, energy efficiencies ... View full abstract»

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  • Cooperative Diversity in Wireless Networks

    Publication Year: 2005, Page(s):1 - 5
    Cited by:  Papers (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3102 KB)

    An ad-hoc network with a base station, a mobile and a third station acting as a relay is analysed. The channels are modelled using path loss, Rayleigh fading and thermal noise. Different combining methods and diversity protocols are compared. In the simulations, the amplify and forward protocol shows a better performance than the decode and forward protocol. To combine the incoming signals the cha... View full abstract»

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  • Relay Transmit Power Control In Cellular Multi-Hop Networks

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2806 KB)

    In cellular multi-hop networks relay stations (RSs) are used to forward transmissions between the base station (BS) and user equipment (UE). The power at which the RS transmits not only determines which UEs it can serve but also the spatial separation at which another RS can reuse the same channel. It therefore jointly controls the routing and the medium access control (MAC) decisions. This means ... View full abstract»

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  • Mobile Agents Based Congestion Aware Routing in Mobile Ad Hoc Networks

    Publication Year: 2005, Page(s):1 - 7
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2168 KB)

    This paper proposes a Mobile Agent based Congestion Aware Routing (MACAR) protocol, for routing in Mobile Ad Hoc Networks (MANETs). Here mobile agents collect network connectivity information based on congestion state and disperse this information across the network. This allows the nodes in the network to make "congestion aware decisions" during route discovery and route maintenance phases. The c... View full abstract»

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  • Robust GOB Intra Refresh Scheme for H. 264/AVC Video Over UMTS

    Publication Year: 2005, Page(s):1 - 4
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3024 KB)

    3G mobile system are designed to provide multimedia services. To fulfill QoS requirements for video applications, a robust video codec should be employed. In this paper, a robust and effective algorithm for Group of Blocks (GOB) Intra refresh in H. 264/AVC is presented. The objective is to mitigate the error propagation and improve the perceptual video quality over the mobile networks. Experimenta... View full abstract»

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  • Ultra-Fast 3G Videotelephony Session Setup

    Publication Year: 2005, Page(s):1 - 3
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3031 KB)

    The establishment of a typical 3G videotelephony (video calls) session is a process that lasts typically around 5 to 8 seconds between today's deployed 3G video-call enabled terminals. This delay is exclusive of call signalling, and is due to the need to complete several protocol procedures as prescribed by the ITU-T H.324 standard and its annex C, including mobile level detection and H.245 messag... View full abstract»

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  • Multimedia Broadcast Multicast Services: Concept & Capabilities

    Publication Year: 2005, Page(s):1 - 4
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3827 KB)

    Being one of the first 3G operators in the world with early UMTS experience, 3 were able to focus immediately on the UMTS opportunities and the challenges ahead, resulting in 3 being one of the early drivers for Multimedia Broadcast Multicast Service (or MBMS). This paper provides a brief history regarding the drivers for MBMS. The paper moves on to explain why the architecture is defined as it is... View full abstract»

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  • Transmission Power Saving Methods for Multimedia Broadcast/Multicast Services in UMTS Networks

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (475 KB)

    In current 3GPP R6 MBMS specifications, multimedia services are expected to be multicast/broadcast to all users or groups of users within the cell range. MBMS Counting Mechanism intends to analyse whether is more economic to transmit the multimedia services in a Point to Point (PtP) or Point to Multipoint (PtM) mode, evaluating in terms of radio resources management if it is preferable to use a si... View full abstract»

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  • Soft Decode and Forward Improves Cooperative Communications

    Publication Year: 2005, Page(s):1 - 4
    Cited by:  Papers (7)  |  Patents (6)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4214 KB)

    Mobile receivers can benefit from an increased spatial diversity through cooperation. Two relaying techniques are typically used: either Amplify and Forward (AF) or Decode and Forward (DF). This contribution presents a new technique which combines the main advantages of both AF and DF. This technique amounts to a DF scheme where all operations are performed in a soft-input soft-output fashion. The... View full abstract»

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  • Sequential Decoding for Mobile Receivers

    Publication Year: 2005, Page(s): 1
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (97 KB)

    Currently many classical detection and decoding algorithms receive new attention in mobile communications. Amongst those classics are low density parity check codes [1], concatenated codes [2], weighted decoding with log-likelihood values as well as soft-in/soft-out decoding as performed by the BCJR algorithm and its derivatives [4], [5]. All four classics show up as key elements in the so-called ... View full abstract»

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  • Interference Suppression in UTRA FDD Downlink Handover Regions

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1366 KB)

    It is known that significant multi-access interference is generated in a handover region in UTRA FDD downlink, particularly when both the Node-Bs involved in a handover are fully loaded. This paper investigates the use of blind minimum output energy (MOE) adaptive detector for suppressing this multi-access interference. A simple solution to the mismatch problem of the MOE detector is also proposed... View full abstract»

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  • Forward-link Interference in CDMA-Based Cellular Networks

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4249 KB)

    In this paper we have studied the in-band interference power caused by macro-cell base stations of a CDMA based cellular network. The impact of macro-cell load, location of the target receiver, service data rate of macro-cell users, and the number of sectors, on the average and standard deviation of the received interference power at a target receiver that works in the same frequency band of macro... View full abstract»

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  • Blind Timing Synchronization for Filter-Bank Multicarrier Wireless Communications

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (3666 KB)

    We describe the performance of a blind timing recovery algorithm for filter bank multicarrier modulation (FBMCM) modems. Our starting point is a the maximum-likelihood criterion. From that, we present the derivation of a closed-loop tracker and demonstrate how to derive a relatively low-complexity scheme with reasonable performance loss. Unlike previously published works, a remarkable acquisition ... View full abstract»

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  • Improvements for the IPv6 Access Network Protection Protocols in Wireless Environments

    Publication Year: 2005, Page(s):1 - 4
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1126 KB)

    Every user that joins a wireless access network to connect to the Internet expects to receive a secure and reliable service. The process of discovering other nodes on the same link as well as the recovery of routing information is known as Neighbour Discovery Protocol (NDP) [1] and until recently little attempt was made to protect it from misuse and attacks. The recently suggested protection metho... View full abstract»

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  • IPv6-Based Architecture for Fast and Cost-Effective Micro-Mobility Management

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (5831 KB)

    To improve mobility management in all IPv6-based wireless networks, optimisation work on Mobile IPv6 (MIPv6) is being standardised. The Hierarchical MIPv6 (HMIPv6) and the Fast Handovers for MIPv6 (FMIPv6) have emerged as the two most promising protocols. However, the optimal integration of both schemes, together with mobility-aware QoS (quality of service) management, remains an open research iss... View full abstract»

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  • TCP Performance Over UMTS Dedicated Channels with Finite RLC Buffer Size

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4953 KB)

    In this paper, simulation results are presented to demonstrate the effects on the performance of a TCP connection over a UMTS dedicated channel when the size of the Acknowledged Mode Radio Link Control (AM-RLC) data buffer at the Radio Network Controller is finite. The consequence of this restriction is that buffer overflow can occur. The TCP flavour (Tahoe, Reno, New Reno or SACK), FTP file size,... View full abstract»

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  • Inter-Operator Cooperation Challenges in SIP-Based Service Architecture of IP Multimedia Subsystem of UMTS

    Publication Year: 2005, Page(s):1 - 6
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4688 KB)

    One of the benefits of the evolution of the third generation mobile systemss such as UMTS (Universal Mobile Telecommunications System) toward the all-IP network architecture is to provide functionalities to support real-time multimedia services. Simple and efficient multimedia session handling characteristics of the Session Initiation Protocol (SIP), candidates it by 3GPP (Third Generation Partner... View full abstract»

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  • VoIP Applications over WLAN with Multistage Interference Cancellation Smart Antennas

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1290 KB)

    In order to improve the transmission quality of wireless local area network (WLAN), incorporation of emerging technologies is required. Smart antennas, as one of the key technologies in future communications, can significantly improve the Signal-to-Interference-plus-Noise ratio (SINR) and hence reduce the transmission errors. Because WLAN uses the unlicensed industrial, scientific, and medical (IS... View full abstract»

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  • Slow Frequency Hopping Assisted MC DS-CDMA Using Large Area Synchronised Spreading Sequences

    Publication Year: 2005, Page(s):1 - 5
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1540 KB)

    The family of Multi-Carrier Direct-Sequence CDMA (MC DS-CDMA) systems exhibits numerous attractive properties, which render them attractive candidates for next-generation wireless communications. We demonstrate that spreading codes exhibiting a so-called interference-free window (IFW) are capable of outperforming classic spreading codes, when the interfering multi-user and multipath components arr... View full abstract»

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