By Topic

Communications Magazine, IEEE

Issue 1 • Date Jan. 1997

Filter Results

Displaying Results 1 - 13 of 13
  • Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full text access may be available. Click article title to sign in or learn about subscription options.
  • A survey of active network research

    Page(s): 80 - 86
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2266 KB)  

    Active networks are a novel approach to network architecture in which the switches (or routers) of the network perform customized computations on the messages flowing through them. This approach is motivated by both lead user applications, which perform user-driven computation at nodes within the network today, and the emergence of mobile code technologies that make dynamic network service innovation attainable. The authors discuss two approaches to the realization of active networks and provide a snapshot of the current research issues and activities. They illustrate how the routers of an IP network could be augmented to perform such customized processing on the datagrams flowing through them. These active routers could also interoperate with legacy routers, which transparently forward datagrams in the traditional manner. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Internet and the “plodding” standard bodies

    Page(s): 12 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (968 KB)  

    The role of the ITU in the development of standards for the Internet is discussed. The speed with which standards are addressed and the relevant procedures in their development are considered View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Digital wireless broadband corporate and private networks: RNET concepts and applications

    Page(s): 42 - 51
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1600 KB)  

    The radio broadband networks suffer from some specific constraints-access protocol efficiency, multipath effects, and limited available frequency bands-which have to be overcome by choosing the best possible compromises in cost/performance on physical and MAC layers. Current WLAN products (1-2 Mb/s at 2.45 GHz), which provide mainly data exchange service, are able to make seamless handover for an indoor cellular network but suffer from relatively low data rates. Even if compliant with the IEEE 802.11 future standard, they do not necessarily lead to interoperability. New generations become necessary for higher data transfer rates, real-time video, and multimedia applications compatible with the future ATM transfer mode. ETSI is proposing the HIPERLAN concept, working in the 5.3 and 17.2 GHz bands. Our contribution to this new standard, called RNET (Radio Network), uses a spread spectrum linear ramp waveform with enhanced capabilities (relative to the TDMA, CSMA/CA, and FDMA structures). The advantages of the MAC layer are highlighted and the first results of a transceiver demonstrator are given View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • IP multicast for mobile hosts

    Page(s): 54 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB)  

    We present alternative designs for efficiently supporting multicast for mobile hosts on the Internet. Methods for separately supporting multicasting and mobility along with their possible interactions are briefly described, and then various solutions to the combined problem are explored. We examine three different multicast delivery mechanisms and compare them based on their efficiency and impact on host protocol software. We describe proposals for integrating multicasting and mobility in the Internet architecture. We first present IP extensions for host mobility and other extensions for multicasting. We then examine local multicasting mechanisms, focusing on a group membership protocol that is optimized for wireless point-to-point links. Next, we examine the problems of sending and receiving multicast datagrams in a wide area network. For multicast reception, we describe three alternative proposals and compare them by examining both their applicability and their performance, as well as possible tradeoffs among the two View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The ETSI computation model: a tool for transmission planning of telephone networks

    Page(s): 70 - 79
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2448 KB)  

    This article deals with the ETSI computation model-the E-model-for evaluating speech communication quality in telephone networks. The reasons why such models are of interest for transmission planning of modern networks and the various subjective tests and customer surveys that must form the basis for the computation algorithms are discussed. Then a survey is given of models that are described in the ITU's documents. The structure of the new E-model and the various considerations taken in its development and verification are also discussed. Results from application of the E-model on typical connections agree well with results from other models and from published subjective tests. In particular, impairments caused by low-bit-rate codecs can be quite well predicted by the model, better than by the hitherto used methodology of “quantizing distortion units.” The E-model has also been used in the process of updating some of the ITU-T C-series Recommendations on transmission planning View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Broadband wireless access

    Page(s): 20 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2760 KB)  

    This article reviews the technologies and potential markets, applications, and architectures for broadband wireless access. The emergence of wireless communications for cellular systems is presented, together with its projected future evolution to mobile wideband systems. The field of broadband access systems, services, and network architectures is also covered, and then systems for broadband wireless communications for indoor local area networks and outdoor public fixed access networks are discussed. Broadband wireless access systems are emerging as a new and growing area of telecommunications, since the ability to provide access without extensive installation of copper or fiber infrastructures make wireless technology well suited for broadband services. Finally, some of the key enabling technologies, such as adaptive antennas and video compression, and the future architectural directions of broadband wireless networks are presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Presentation methods: Web-to-host integration

    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    With the increasing popularity of the Internet new implementations for the Internet and Web browsers are appearing almost every day. One such implementation is Web-to-host integration. The author reviews this new phenomenon and discusses some of the possible benefits it has to offer. The key to successful Web-to-host integration lies in thorough implementation planning and careful selection among the different implementation alternatives to better suit a multitude of company-specific integration realities and needs View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • IP switching and gigabit routers

    Page(s): 64 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1020 KB)  

    To cope with the growth in the Internet and corporate IP networks, we require IP routers capable of much higher performance than is possible with existing architectures. This article examines two approaches to the design of a high-performance router, the gigabit router and the IP switch, and then provides some detail on the implementation of an IP switch and the protocols associated with IP switching View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • vBNS: the Internet fast lane for research and education

    Page(s): 60 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1184 KB)  

    The very-high-speed Backbone Network Service (vBNS) is a National Science Foundation (NSF) sponsored high-performance network service implemented by MCI. It was first implemented as an IP/ATM network with an OC-3 (155 Mb/s) infrastructure. The vBNS was activated on a test basis late in 1994, and the full network topology was on-line in early 1995. The NSF's high-performance connections program is now expanding the vBNS to reach more research and education (R&E) institutions, and the vBNS backbone is currently being upgraded to OC-12 (622 Mb/s) speeds. The vBNS supports scientific applications between NSF-supported supercomputer centers (SCCs), directly connected research institutions, and research institutions that are served by other networks. The vBNS also provides a test environment for early deployment and evaluation of new internetworking technologies View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New concepts and technologies for achieving highly reliable and high-capacity multimedia wireless communications systems

    Page(s): 34 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2760 KB)  

    The rapid growth of multimedia wireless communications services forces the development of advanced digital wireless systems with high reliability and high speed as well as flexibility for varying traffic conditions. To achieve such advanced wireless systems. New system design concepts different from the conventional ones aiming at increasing system capacity for voice transmission would be required. Since multimedia wireless communications require high quality, high speed, and high flexibility as well as temporary and spatial control of traffic under severe fading environments, the so-called conventional system design concept will be insufficient. New system design concepts and techniques for achieving highly reliable and high-capacity multimedia wireless communications are discussed using both time division multiple access (TDMA) and code division multiple access (CDMA) systems. The demands for high-speed and high-reliability mobile, personal, and multimedia wireless communications services strongly require matching with the trunk network constructed by a broadband optical fiber system or wired system View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An overview of wireless broadband communications

    Page(s): 28 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2076 KB)  

    A brief overview of wireless broadband communication systems, those providing a data rate higher than 2 Mb/s and up to 155 Mb/s, is done by addressing some of the applications and services that are foreseen, as well as some of the technical challenges that need to be solved, and by referring to some safety considerations. After an introduction, the need for high data rates is justified, and possible applications are listed and compared, concerning user mobility and bandwidth. Then an analysis of the propagation aspects at the bands foreseen for these systems-microwaves, millimeter waves and infrared-is presented, also addressing the issue of the antennas and batteries for these systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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

Meet Our Editors

Editor-in-Chief
Osman Gebizlioglu
Huawei Technologies