By Topic

Communications Magazine, IEEE

Issue 8 • Date Aug. 1999

Filter Results

Displaying Results 1 - 13 of 13
  • Conference Calendar

    Page(s): 22 - 32
    Save to Project icon | Request Permissions | PDF file iconPDF (805 KB)  
    Freely Available from IEEE
  • CMOS wireless transceivers: the new wave

    Page(s): 119 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    A new generation of wireless transceivers is being intergrated into CMOS IC technology, which so far has been used mainly to realize digital and mixed analog-digital baseband circuits. This article reviews some of the RF CMOS circuit design techniques, and shows how an understanding of the strengths and weaknesses of these circuits influences choice of radio architecture. The CMOS approach to radio design calls for the elimination of discrete components in favor of high levels of on-chip integration which freely use translators and mix analog and digital functionality; in these respects, it departs from traditional RF circuit practices. Successful wireless devices of the future will require that radio system design evolve around these new trends in RF integration View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Configurable logic for digital communications: some signal processing perspectives

    Page(s): 107 - 111
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    For the past two decades software programmable digital signal processors and ASICs have provided hardware solutions for signal processing system designers. A new option has become available: field programmable gate arrays. FPGA-based DSP platforms allow the designer to realize a data path that exactly matches the required processing, while at the same time maintaining the flexibility of a software approach. This article presents an overview of some FPGA DSP applications. Several filter designs are presented, and the use of CORDIC arithmetic for constructing an FPGA carrier recovery loop is outlined. In addition to presenting design examples that can be realized using present-generation devices and tools, we take a brief look at how the dynamic reconfiguration aspect of certain FPGAs could be exploited in future-generation communication technologies View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Survivability in a new pan-European carriers' carrier network based on WDM and SDH technology: current implementation and future requirements

    Page(s): 63 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    A pan-European carriers' carrier network, like other carrier networks, must cope with the enormous traffic inflation by introducing appropriate network solutions. WDM technology is the solution adopted by GTS Carrier Services' Trans European Network unit (TEN, formerly known as Hermes Europe Railtel), driven by bandwidth requirements, infrastructure limitations, flexibility, and cost. The introduction of such new technology presents specific technical issues, although it lays the foundation of future optical networking. Network outages are an important concern since, by using WDM, tens of gigabits of data are transported on each fiber. On one hand, traffic interruption is avoided as much as possible through secure fiber routings, cable protection, high design and equipment standards, and security. On the other hand, network protection techniques are used to limit the impact on services when inevitable outages occur. We explain the role of the different technologies in TEN's network. We concentrate on WDM and optical networking where optical channels are used to interconnect the equipment used by the different technologies. We focus on optical network protection techniques and illustrate that a clear requirement exists for this. We also emphasize interworking issues that come into play when multiple technologies are combined in the same network. It is not the intent to discuss only future requirements, but also to explain how the different aspects are currently implemented in TEN's operational network View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The evolution of transport network survivability

    Page(s): 44 - 51
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    The bandwidth explosion ushered in by the popularity of the Internet has spurred the acceleration in the development and deployment of equipment supporting packet-based services. This-coupled with the widespread deployment of dense wavelength-division multiplexed systems in the core transport network to satisfy the corresponding increase in capacity demand-has led network planners to reconsider traditional approaches to network survivability. Existing architectures for transport network survivability were developed based on a ubiquitous circuit-switched/TDM network paradigm. As tariffed services increasingly migrate from circuit-switched/TDM to packet-switched/DWDM networks, survivability architectures must also evolve to meet the service requirements of this “new” packet-switched/DWDM network paradigm. We begin with an overview of existing strategies for providing transport network survivability, followed by an analysis of how the architectures for network survivability may evolve to satisfy the requirements of emerging networks View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Architectures for ATM network survivability and their field deployment

    Page(s): 88 - 94
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    Future networks must offer extremely high levels of reliability because information has become critical to the continued well-being of society. This article shows the approaches to the survivable ATM network. The reliability requirements of future networks are discussed first. Development results of three typical restoration architectures (automatic protection switch (APS), self-healing network (SHN), and failure-resistant virtual path (FRVP)) for ATM networks are then shown. Next, we describe current progress in standardization activities. They also discuss open issues that must be resolved in future studies View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The evolution of a reliable transport network

    Page(s): 52 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    This article shows how transport networks may evolve in the future, driven by new technologies and new customer requirements for cost, reliability, and traffic growth. It does not simply compare new technologies and architectures, but accepts that most operators are not starting with a green-field site. It therefore also addresses the operator's problems of introducing and integrating new technologies into existing transport networks and migrating services from one transport technology to another. This in turn drives different technologies to evolve to new levels of reliability over time. The article is written from the perspective of an established European network operator, and differences are brought out from the evolution of networks in North America View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Photonic transport technologies to create robust backbone networks

    Page(s): 78 - 87
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB)  

    This article discusses the role of the new optical layer in terms of transport layer architecture and functional allocations. The envisaged future photonic network is identified, and the technologies needed to realize reliable communication are clarified. Network-node interface technologies, and network protection and restoration strategies are discussed in detail, since these are key to developing a network with high integrity that will be a main pillar of the future information society. Finally, applications of photonic network technologies and a network design example are presented; the IP backbone network based on optical path technologies is highlighted View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Future transport network architectures

    Page(s): 96 - 101
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    The architecture of today's long distance transmission networks, which we call the baseline architecture, is a complex and multilayered hierarchy of TDM circuits. One premise of the baseline architecture is that restoration from network failures is provided mostly by SONET/SDH rings. This article presents an alternative architecture that uses ATM and optical layer cross-connect technology for TDM services. Using a sophisticated set of network design tools developed at AT&T Labs-Research, we show that the alternative architecture offers dramatic capital savings and improved network efficiency over the baseline architecture. Most of this savings can be attributed to use of OLXC mesh network restoration, which makes more efficient use of capacity than SONET/SDH rings, and use of ATM switching for transport of TDM circuits, which consolidates the numerous TDM equipment layers inherent to the baseline architecture. In addition, motivated by the rapid growth of IP services, we analyze in the alternative architecture whether to provide restoration for IP services in the IP layer itself, by rerouting packets over precalculated restoration paths with MPLS, or to alternatively provide restoration of failed IP layer links in the OLXC layer. One potential advantage of IP layer restoration is that network operators may choose to only restore a fraction of the services, in particular the “priority” services, affected by a network failure. This article gives some methodology of how to determine this fraction at which IP layer restoration is cost-competitive with OLXC restoration View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Recent developments in enabling technologies for software defined radio

    Page(s): 112 - 117
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    In response to the technical challenges surrounding the realization of software defined radio, high-performance digital signal processors and related software have emerged as key enabling technologies. This article focuses on high-performance digital signal processing architectures and devices. The partitioning of the transceiver functions between DSPs and programmable dedicated hardware is examined View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mode switching and software download for software defined radio: the SDR Forum approach

    Page(s): 104 - 106
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    The proliferation of air interfaces has created the need for a standard way of switching services supported by a wireless system and downloading new code to systems in the field. Both conventional and software defined systems need this capability. This article describes the work of the SDR Forum in developing such a switcher/downloader standard View full abstract»

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

    Page(s): 70 - 76
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    The integration of different technologies such as ATM, SDH, and WDM in multilayer transport networks raises many questions regarding the coordination of the individual network layers. Especially in the area of network survivability, much can be gained by a better alignment of the healing actions taken by different network layers in case of outages. Survivability issues encountered in a multilayer environment include, among others: how to identify the original failure cause, how to appoint for each failure a layer responsible for its healing, how to let different layers interwork, and how to provide spare resources in an efficient way View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Sprint long distance network survivability: today and tomorrow

    Page(s): 58 - 62
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    The high reliability exhibited by the Sprint long distance network is the result of many interrelated factors. The network utilizes robust architectures, systems, and equipment to provide a reliable transport infrastructure. Redundant equipment, conservative synchronization, protected power, and other factors combine to form a dependable foundation. New architectures and systems are under development to meet the changing demands of customers. This article summarizes Sprint's current network reliability, and emerging demands and technology, and presents possible directions for the future Sprint network. Sprint selected the SONET four-fiber bidirectional line switched ring (4F BLSR) architecture for the vast majority of its transport network architecture. A 4F BLSR architecture requires four fibers, or four optical wavelengths of wave division multiplexing (WDM), to accommodate a work and protect path in each direction around a ring of network elements or add-drop multiplexers (ADMs) 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
Sean Moore
Centripetal Networks