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Communications Magazine, IEEE

Issue 10 • Date Oct 2000

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Displaying Results 1 - 17 of 17
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  • A multicarrier allocation (MCA) scheme for variable-rate 3Gwireless systems

    Page(s): 86 - 91
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    High spectral efficiency and flexible data rate access are the main focus of future wireless networks. Multiple channel allocation schemes have the potential of achieving this goal. By assigning multiple slots and/or multiple carriers to one user, it is possible to provide a flexible data rate with quite low complexity. In this article we propose a simple allocation scheme where each user is assigned a fixed group of carriers. These carriers are adaptively used depending on the interference situation within the system. The system performance in terms of average throughput is investigated for two different types of allocation schemes: a fully centralized scheme and a distributed one that uses frequency diversity as a mean of improving the user link quality. The obtained results show that both schemes improve the system throughput over single carrier allocation without affecting the capacity of the system in terms of number of users per cell View full abstract»

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  • IP-centric control and management of optical transport networks

    Page(s): 161 - 167
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    Previous techniques for the management and control of optical transport networks are proving inadequate in today's rapidly evolving multivendor environments. This article examines the issues and challenges involved in developing a standardized optical network control plane. The control of optical transport networks is decomposed into provisioning models, a circuit provisioning process based on signaling, a neighbor and service discovery process, and a topology and resource discovery process. Unique properties and challenges of optical transport networks are explained in the context of these functions View full abstract»

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  • Video transcoding proxy for 3Gwireless mobile Internet access

    Page(s): 66 - 71
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    Transcoding proxies for mobile World Wide Web access have been developed. In the near future, wideband mobile communication systems such as IMT-2000 will emerge, and these proxies will have to cope with a variety of media such as video. In this article we identify issues involved in viewing a video stream in a mobile computing environment; to handle these issues, we propose a video transcoding system and its control method. These mechanisms provide stable transmission of video data and comfortable video viewing on user clients by estimating the communication conditions, client device capabilities, and user preferences View full abstract»

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  • Control and management in next-generation networks: challenges and opportunities

    Page(s): 94 - 102
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    This article discusses the challenges and opportunities associated with a fundamental transformation of current networks toward a multiservice ubiquitous infrastructure with a unified control and management architecture. After articulating the major driving forces for network evolution, we outline the fundamental reasons why neither the control infrastructure of the PSTN nor that of the present-day Internet is adequate to support the myriad of new services in next-generation networks. Although NGN will inherit heavily from both the Internet and the PSTN, its control and management architecture is likely to be radically different from both, and will be anchored on a clean separation between a QoS-enabled transport/network domain and an object-oriented service/application domain, with a distributed processing environment that glues things together and universally addresses issues of distribution, redundancy, and concurrency control for all applications. Finally, we allude to the transition issues and show how voice-over-packet services are emerging as the bootstrap application for marshaling in the NGN architecture View full abstract»

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  • Comparison of multi code link-layer transmission strategies in 3G wireless CDMA

    Page(s): 58 - 64
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    Within this article we investigate the possibility of using multiple codes within a code-division multiple access system to reduce the losses in a delay bounded transmission for 3G multimedia applications over wireless links with fading. Multiple codes are used to recover from gaps on the wireless link after a fading period by means of ARQ-type retransmissions. One key feature of our work is that even a small number of multiple codes leads to a dramatic reduction of losses regarding delay bounds of multimedia applications View full abstract»

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  • Optical Domain Service Interconnect (ODSI): defining mechanisms for enabling on-demand high-speed capacity from the optical domain

    Page(s): 168 - 174
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    Signaling and control mechanisms at the electro-optical boundary, such as IP routers, will one day interconnect with the intelligent optical switched network. Creating this open boundary between the electrical and optical domains is the central goal of the Optical Domain Service Interconnect, a coalition of more than 100 companies formed in 2000. ODSI is working to provide an interface to the optical network that can quickly implement and deploy bandwidth on demand. The initiative previously defined a specification for interoperability. Once in use, network elements at the edge of the intelligent optical network can establish optical paths in real time, as demanded by bandwidth demands or needed to support new and innovative high-speed services View full abstract»

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  • Efficient call admission control for heterogeneous services in wireless mobile ATM networks

    Page(s): 72 - 78
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    An efficient call admission control scheme for handling heterogeneous services in wireless ATM networks is proposed. Quality-of-service provisioning of jitter bounds for constant bit rate traffic and delay bounds for variable bit rate traffic is used in the CAC scheme to guarantee predefined QoS levels for all traffic classes. To reduce the forced handoff call dropping rate, the CAC scheme gives handoff calls a higher priority than new calls by reserving an appropriate amount of resources for potential handoff calls. Resource reservation in the CAC scheme makes use of user mobility information to ensure efficient resource utilization. Simulation results show that the proposed CAC scheme can achieve both low handoff call dropping rate and high resource utilization View full abstract»

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  • Optical layer signaling: how much is really needed?

    Page(s): 154 - 160
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    This article challenges the emerging industry trend of adapting Internet-style distributed network-control with its full complexity for the optical transport network. Instead, we argue that an extensive telecom-style network management interface augmented with a minimal control plane and a service layer interface between management systems is more appropriate for the real needs of the optical layer. This approach will allow more flexibility in extending the interoperability between vendors and carriers as our understanding of these networks grows, increase the reliability of the network, and be a better fit for the telecom service provider. On the other hand, the simplicity of use and automation the Internet control plane promises can just as easily be achieved with our proposal View full abstract»

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  • Voice over IP signaling: H.323 and beyond

    Page(s): 142 - 148
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    Signaling has been one of the key areas of Voice over IP (VoIP) technologies since inception. H.323 was the key protocol that allowed interoperability of VoIP products and moved the industry away from the initial proprietary solutions. Once the VoIP industry started maturing, some limitations of H.323 came to light. In this article we provide an overview of H.323, describe its capabilities, and discuss how its limitations are being addressed using the concept of gateway decomposition. We also discuss how H.323 can coexist with other protocols such as MGCP, H.248, and SIP which are attracting a lot of interest in the VoIP industry today View full abstract»

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  • Megaco/H.248: a new standard for media gateway control

    Page(s): 124 - 132
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    Arango and Huitema (1998) were the first to propose a new architecture for voice-over-IP networks, physically separating call control from media and bearer control. This separation created the need for a new class of protocol to link the two units. The Media Gateway Control Protocol is now seeing limited deployment for that purpose. However, MGCP is optimized for circuit to packet voice connections and has a North American bias in the types of events it can handle. A new protocol has been standardized by the IETF Megaco Working Group working together with ITU-T Study Group 16, which has been published as both a standards-track RFC and ITU-T Recommendation H.248. This protocol extends media gateway control to include a transport-independent connection model, support for more advanced services such as multimedia conferencing, and support for operation in countries around the world. The present article provides a technical description of the features of Megaco/H.248 View full abstract»

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  • The Session Initiation Protocol: Internet-centric signaling

    Page(s): 134 - 141
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    The Session Initiation Protocol (SIP) provides advanced signaling and control functionality for a wide variety of multimedia services. SIP can efficiently and scalably locate resources based on a location-independent name and then negotiate session characteristics. It can find use in applications ranging from Internet telephony and conferencing to instant messaging, event notification, and the control of networked devices. We summarize the main protocol features and describe a range of extensions currently being discussed within the Internet Engineering Task Force View full abstract»

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  • Developing next-generation distributed applications with QoS enabled DPE middleware

    Page(s): 112 - 123
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    This article describes how recent advances in distributed object computing middleware are enabling the creation of common quality-of-service capabilities that support next-generation distributed applications. DOC middleware helps to simplify and coordinate applications in order to leverage the underlying network and end-system QoS architectures more effectively. This article also describes a QoS-enabled middleware framework used to customize the CORBA audio/video streaming service for applications on multiple operating system platforms View full abstract»

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  • TINA for services and advanced signaling and control in next generation networks

    Page(s): 104 - 110
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    This article describes solutions that use the Telecommunications Information Networking Architecture and its advanced service architecture and call model, for the definition of services and advanced signaling and control in next-generation networks. It presents both the solutions for extending traditional signaling and/or interacting and interworking with it, and the way the TINA service architecture can constitute an intelligent service platform providing multiple value-added services to the PSTN and the Internet. In each case, the article provides details and examples to demonstrate the case and illustrate the solutions for trendy technologies such as mobile and the Internet View full abstract»

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  • Dynamic resource scheduling schemes for W-CDMA systems

    Page(s): 80 - 84
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    W-CDMA is the strongest candidate for the air interface technology of third-generation wireless communication systems. Dynamic resource scheduling is proposed as a framework that will provide QoS provisioning for multimedia traffic in W-CDMA systems. The DRS framework monitors the traffic variations and adjusts the transmission powers of users in an optimal manner to accommodate different service classes efficiently. Variable and optimal power allocation is suggested to provision error requirements and maximize capacity, while prioritized queuing is introduced to provision delay bounds. A family of DRS algorithms has been devised along these dimensions for obtaining different levels of QoS. The DRS schemes are discussed in terms of queuing and bandwidth allocation with an emphasis on their impact on delay QoS View full abstract»

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Aims & Scope

IEEE Communications Magazine covers all areas of communications such as lightwave telecommunications, high-speed data communications, personal communications systems (PCS), ISDN, and more.

Full Aims & Scope

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Editor-in-Chief
Sean Moore
Centripetal Networks