Showing papers on "Broadband networks published in 1997"

Multiservice Loss Models for Broadband Telecommunication Networks

Abstract: Loss networks ensure that sufficient resources are available when a call arrives However, traditional loss network models for telephone networks cannot cope with today's heterogeneous demands, the central attribute of Asynchronous transfer Mode (ATM) networks This requires multiservice loss models This text presents mathematical tools for the analysis, optimization and design of multiservice loss networks These tools are relevant to modern broadband networks, including ATM networks Addressed are networks with both fixed and alternative routing, and with discrete and continuous bandwidth requirements Multiservice interconnection networks for switches and contiguous slot assignment for synchronous transfer mode are also presented

Downloading applications software through a broadcast channel

Abstract: Set-top terminals utilized in broadband broadcast networks are becoming increasingly intelligent (programmable). However, transmitting executable code, data and interactive audio/video materials through a selectively dedicated link requires an extensive, broadband point-to-point broadband network, which is prohibitively expensive to implement for large numbers of customers. The present invention provides for downloading application software and transmitting audio/video information through one channel of a digital broadcast network. The network also provides two-way, low-speed data communications capacity, e.g. for signaling and/or interactive text services. Signaling via data communication with a text server controls downloading of executable code from the digital broadcast channel into a programmable digital set-top terminal. Execution of the downloaded code in turn controls selective capture and presentation of audio and video segments received over one of the digital broadcast channels. Resident operating system and application software in the terminal provides all communication with nodes of the network. The downloaded code forms a non-resident application having a set of predetermined function calls for activating communication functions of the resident software.

Traffic models in broadband networks

Abstract: Traffic models are at the heart of any performance evaluation of telecommunications networks An accurate estimation of network performance is critical for the success of broadband networks Such networks need to guarantee an acceptable quality of service (QoS) level to the users Therefore, traffic models need to be accurate and able to capture the statistical characteristics of the actual traffic We survey and examine traffic models that are currently used in the literature Traditional short-range and non-traditional long-range dependent traffic models are presented The number of parameters needed, parameter estimation, analytical tractability, and ability of traffic models to capture marginal distribution and auto-correlation structure of the actual traffic are discussed

Broadband wireless access

Abstract: 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.

An overview of wireless broadband communications

Abstract: 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.

Reduced-complexity equalization techniques for broadband wireless channels

Abstract: This paper presents reduced-complexity equalization techniques for broadband wireless communications, both outdoors (fixed or mobile wireless asynchronous transfer mode (ATM) networks) and indoors [high-speed local-area networks (LANs)]. The two basic equalization techniques investigated are decision-feedback equalization (FE) and delayed decision-feedback sequence estimation (DDFSE). We consider the use of these techniques in highly dispersive channels, where the impulse response can last up to 100 symbol periods. The challenge is in minimizing the complexity as well as providing fast equalizer start-up for transmissions of short packets. We propose two techniques which, taken together, provide an answer to this challenge. One is an open-loop timing recovery approach (for both DFE and DDFSE) which can be executed prior to equalization; the other is a modified DFE structure for precanceling postcursors without requiring training of the feedback filter. Simulation results are presented to demonstrate the feasibility of the proposed techniques for both indoor and outdoor multipath channel models. The proposed open-loop timing recovery technique plays a crucial role in maximizing the performance of DFE and DDFSE with short feedforward spans (the feedforward section of DDFSE is a Viterbi sequence estimator). A feedforward span of only five is quite sufficient for channels with symbol rate-delay spread products approaching 100. The modified DFE structure speeds up the training process for these channels by 10-20 times, compared to the conventional structure without postcursor precancellation. The proposed techniques offer the possibility of practical equalization for broadband wireless systems.

Broadband cable television and computer network

Abstract: A communication system is provided which may comprise an upstream source of broadband communications and a downstream local area network, wherein the upstream source of broadband communications is coupled to the downstream local area network through a notch filter In some embodiments, the upstream source of broadband communications may be a cable television service provider, and the local area computer network may use existing cable television wiring as communication cable

Load management in distributed video servers

Abstract: We define and formulate various policies for load management in distributed video servers. We propose a predictive placement policy that determines the degree of replication necessary for popular videos using a cost based optimization procedure based on a priori predictions of expected subscriber requests. For scheduling requests, we propose an adaptive scheduling policy that compares the relative utilization of resources in a video server to determine an assignment of requests to replicas. To optimize storage utilization, we also devise methods for dereplication of videos based on changes in their popularities and in server usage patterns. Performance evaluations indicate that a load management procedure which uses a judicious combination of the different policies performs best for most server configurations. Advances in storage technologies are making high performance video servers a reality. These video servers are being deployed over emerging broadband networks to deliver a variety of interactive, digital video services to thousands of residential subscribers. To meet the scalability requirements in such large deployments, distributed video server architectures are being considered (M. Buddhikot and G. Parulkar, 1995). We propose various methods for load management that are targeted at improving the cost effectiveness of distributed video servers.

An FPGA-based coprocessor for ATM firewalls

Abstract: This implementation of the firewall enables a high degree of traffic selectability yet avoids the usual performance penalty associated with IP level firewalls. This approach is applicable to high-speed broadband networks, and asynchronous transfer mode (ATM) networks are addressed in particular. Security management is achieved through a new technique of active connection management with authentication. Past approaches to network security involve firewalls providing selection based on packet filtering and application level proxy gateways. IP level firewalling was sufficient for traditional networks but causes a severe performance degradation in high speed broadband environments. The approach described in this paper discusses the use of an FPGA-based front end processor that filters relevant signaling information to the firewall host while at the same time allowing friendly connections to proceed at line speed with no performance degradation.

On the cost structure of future wideband wireless access

Abstract: Wireless data services have attracted increasing attention in the last few years. Boosted by the massive use of popular Internet-based services such as email, WWW, etc., wireless wideband networks capable of supporting mobile multimedia services are being planned. An important requirement has been postulated for these wideband services-they cannot be substantially more expensive than the voice services offered today. Connection revenues cannot be expected to be proportional to the bandwidth provided. We use some simple cost models to analyze the cost structure of some proposed wireless infrastructure architectures supporting multimedia services. Both infrastructural costs and spectrum costs are included in the analysis. Results show that universal wideband coverage has an end-user connection cost that is almost directly proportional to the bandwidth provided. This is in contrast with wireline optical networks were the bandwidth cost is virtually "flat". We show further that for some hierarchical architectures, with wideband "hot-spot" service supplemented by wide-area, low data rate, coverage there exist some scenarios where a more favorable cost structure more suited for wideband multimedia applications can be achieved. The implication of the results is to use multimedia terminals and services tolerant to variable data rates and communication quality not only as proposed in a transient introduction phase, but also in the long-term perspective.

Residential broadband Internet services and applications requirements

Abstract: Consumer interest in accessing the Internet for browsing the World Wide Web has exploded in the past two years. The current narrowband residential Internet access infrastructure using dial-up through the PSTN not only is too slow, but also leads to high service blocking probability. Hence, providing an "always-on" high-speed Internet access service has been viewed as the new killer application for residential broadband networks. Residential broadband Internet service design requires understanding of the networking requirements of broadband Internet applications. This article provides a framework for characterizing applications requirements in general, with special emphasis on Internet applications such as Web browsing. The author presents a classification of applications based on their networking requirements, and discusses the traffic and quality of service requirements for each application class.

Method of using a narrowband server to provide service features to broadband subscribers

Abstract: A method for providing narrowband-related service features to subscribing broadband lines comprises establishing a composite voice path interconnecting a narrowband server and the subscribing broadband line via a broadband switching fabric. Particularly, a call set-up signal is received in a broadband call processor, converted to narrowband signaling format and extended to a designated narrowband server. Responsive to receipt of the call set-up signal, the designated narrowband server establishes a narrowband voice path interconnecting a narrowband network element to a synchronous-asynchronous converter. Subsequently, the broadband call processor establishes a broadband segment interconnecting the subscribing broadband line with the synchronous-asynchronous converter. The broadband segment corresponds to the narrowband voice path to form a composite voice path. The composite voice path is used by the designated narrowband server to provide narrowband-related service features to the subscribing broadband line. After a call in which narrowband-related features may be invoked has been disconnected, the composite voice path is released.

Diversity and equalization in frequency domain a robust and flexible receiver technology for broadband mobile communication systems

Abstract: A new receiver structure for broadband mobile communication systems is presented. Signals with block oriented single-carrier modulation are processed in frequency domain. By using a combination of diversity and equalization, an excellent receiver performance can be achieved even for time-variant and frequency-selective radio channels.

PCS mobility support over fixed ATM networks

Abstract: As broadband multimedia services and wireless services become popular, there is growing interest in the industry to support ATM over a wireless link, and wireless access to fixed ATM networks. We focus on the internetworking of PCS and ATM networks, in which the air interface remains one of the PCS standards and the backbone is an ATM network with mobility support. It is desirable to minimize the impact of the internetworking and mobility support on the existing/emerging PCS and ATM specifications. A network architecture, a protocol reference model, and signaling protocols for PCS mobility support over fixed ATM networks are described. They are compared against other implementation alternatives and the trade-offs are discussed. Some performance results of the proposed architecture are also presented.

ATM Network Resource Management

Abstract: From the Publisher: Many companies are turning to ATM to speed the transfer of information over networks: However,ATM is especially complex and costly to manage. This book covers ATM network management in both technical and dollars and cents terms. It presents a coherent detailed framework to help network managers optimize their resources in implementing and maintaining ATM. Readers will also find guidance on managing non-ATM high-performance broadband networks.

Broadband data interface

Abstract: A broadband data interface and a broadband digital interface couples broadband systems to digital client systems. The broadband digital interface is coupled to the digital client systems to transfer data to and from the digital client systems. The broadband digital interface is owned and controlled by the digital client systems. The broadband data interface interfaces broadband systems to the broadband digital interface. The broadband data interface is customized for the particular broadband system such that the broadband data interface is owned and controlled by the operator of the broadband system. The broadband data interface contains a broadband receiver and network access control to permit the broadband system operator to implement access control for data transmitted from the broadband system to the clients. The broadband data interface further includes a broadband transmitter and broadband access control to transfer data from the broadband digital interface to the broadband system and to provide access control to the broadband system.

A broadband wireless access system at 28 GHz

Abstract: This paper describes a broadband local access system at 28 GHz. In the United States these systems are generally referred to as Local Multipoint Distribution Service or LMDS. The FCC bandplan is discussed and a proposed utilization of the spectrum is presented. The architecture for an LMDS system is described along with link budgets and capacity estimates.

Wideband multi-rate DS-CDMA for next generation mobile communications systems

Abstract: The design concept of wideband multi-rate DS-CDMA (W-CDMA) that can support various services with different data rates and also flexible system deployment is presented. It is characterized by asynchronous cell site operation with fast cell search algorithm, pilot symbol assisted coherent reverse/forward links, and forward links that use tree-structured orthogonal multi-spreading factor (SF) codes. Adaptive antenna array diversity and interference canceller are designed to further enhance the transmission quality and increase the link capacity. Field experiments including 2 Mbps transmission are also presented.

Onboard switching for ATM via satellite

Abstract: This article presents an architecture for onboard ATM switching. The constraints of the space environment and the associated delays (especially with geostationary satellites) create often conflicting requirements for the implementation of ATM via satellite. These requirements must be considered when designing onboard equipment. The article suggests that the use of MF-TDMA framing and of physical-layer scheduling as a preswitching stage allows for the use of standard switch fabrics onboard with additional fault tolerance and buffer mechanisms. The details of the scheduler and of the RF front end, including demodulation and demultiplexing, are presented as well as suitable switch fabrics and their performance/implementation impact. ATM is now widely considered the delivery medium for the broadband services of the future. This fact has also attracted the attention of the satellite community. Current satellite ATM trials have concentrated on trunking applications using available broadcast satellites. However, the US FCC filings for Ka band satellites, as well as Canadian W and European initiatives, have focused on a new generation of digital regenerative multibeam onboard processing satellites.

Optimal spare capacity design for various protection switching methods in ATM networks

Abstract: With the employment of very high capacity transmission systems in high-speed broadband networks (B-ISDN, broadband integrated services digital network), based upon the asynchronous transfer mode (ATM), the consequences of a link failure have increased, since even during a short disconnection a large volume of data is lost. These networks can be made safer against failure, if in the case of a transmission link outage the affected traffic is routed over still intact network parts. This paper describes various protection switching methods for ATM networks and presents mathematical models which can be used to determine globally optimal restoration paths and to dimension spare capacities in the network. Finally, the results are discussed and the various methods are compared.

The residential gateway

Abstract: Burgeoning competition in telecommunications is multiplying the number of communications paths into the home-but a standard multinetwork connection could sort them out. Services going into the residence may enter over copper wires, hybrid fiber coax, RF transmission, fiber to the curb, or, most importantly, by any combination of these sources and structures. To have a successful market, residential customers must be able to move smoothly from one combination of these offerings to another so that the customers consider the move worthwhile. For this multinetwork-to-multiservice interconnection to have value, it must be simple, and that simplicity is the basis for the residential gateway concept. In other words, the substantial complexity of the interconnection must be hidden from the consumer. The concept is essentially the development of a set of interface standards between the broadband residential access networks and the communication services (the internal networks) required for the consumer's home.

Full service optical access networks: ATM transport on passive optical networks

Abstract: Multimedia communication has become the driving force for installing broadband systems in the public network. Different alternative solutions have been presented to realize a broadband interactive access network, such as installing optical fiber or upgrading the existing copper network with ADSL for twisted pair or hybrid fiber coax for CATV networks. Among these alternatives, optical fiber access networks are seen as the most future-safe solution. Especially, passive optical networks prove to be a cost-effective way to introduce fiber into the access network. This article presents ATM-based transport on passive optical networks, starting with a current implementation of an ATM-PON (APON) system that has already been installed for various trials. It further describes the evolution of APON systems to high-splitting, long-range PONs. The increase in both number of subscribers and distance range is discussed in combination with some specific technological issues such as upstream burst mode optical amplification. Special emphasis is placed on the work carried out within the scope of the ACTS PLANET project.

Residential Broadband

Abstract: From the Publisher: This comprehensive, accessible resource organizes and puts in context the complexities and variables that characterize full-scale deployment of residential broadband networks. This book provides valuable information and perspective for anyone with an interest in implementing, guiding, and predicting the future of residential broadband technologies: product developers, engineers, network designers, business people, lawyers, regulators, investors, and industry analysts.

Architectures for broadband residential IP services over CATV networks

Abstract: The current state of the art in digital broadband access technologies to support emerging telecommunications services makes imminent the introduction of interactive broadband services-including data, video and the Internet-into the residential market. Over the last few years, much attention has been paid to the development of media access control protocols for cable TV networks that will allow the immediate support of broadband data services as the first step toward enhanced communications services for residential users. We review some of the architectural options that must be carefully considered in order to deliver Internet protocol (IP) services to such users in an efficient yet flexible manner. Future residential cable data services are expected to deliver Internet access, work-at-home applications, small business access, local area network LAN-LAN interconnect, and LAN emulation services over cable (CATV) networks.

Broadband to the home (BTTH): architectures, access methods, and the appetite for it

Abstract: The demand for high-volume data transfer to the home for interactive multipurpose residential multimedia applications (such as tele-education, interactive on-demand entertainment, home shopping, browsing the World Wide Web to retrieve up-to-date information) and telecollaboration, including telecommuting to work, are continuously increasing. Technological advances and the 1996 Telecommunications (Deregulation) Act allow both telephone and television service providers to compete in each other's territory for providing broadband services to the home (BTTH). BTTH refers to broadband data services which may or may not use a high bandwidth link. It essentially gives the end user an impression or feeling that megabit-rate data transmission is occurring to/from the terminal, so the benefits of broadband services are enjoyed at the most convenient time within the comforts of home. It can be achieved for example, by using twisted pair copper wire telephone line using various types of digital subscriber line (xDSL) modems installed at both ends of the line. Issues and challenges of BTTH are discussed, in addition to describing future position(s) of the traditional service providers.

The full services access networks initiative

Abstract: An international collaboration aimed at kick-starting investment in broadband access networks is discussed. This activity has focused on producing requirements and design solutions for a low-cost full services access network which is suitable for both home and business service delivery, starting from the telco position where enormous investment has already been made in copper pair technology. This article reports on the drivers, key issues, and top-level view of key requirements as agreed on by the seven major telcos and ten leading suppliers involved until June 1996.

Multi-class connection admission control policy for high speed ATM switches

Abstract: Broadband networks based on ATM have to support multiple classes of services with widely different traffic characteristics and quality of services. We propose and develop a multi-class connection admission control (CAC) policy that supports cell loss and delay requirements. In this model-based CAC, the source traffic is described in terms of the usage parameter control (UPC) parameters. Through careful analysis and approximations, we derive simple closed-form formulas to calculate the bandwidth required to meet guarantees on quality of service (QoS). While being robust, the CAC achieves a high level of resource utilization and can be easily implemented for real-time admission control.

Resource assignment in a fixed broadband wireless system

Abstract: We propose a time slot reuse partitioning (TRSP) scheme for resource assignment in packet-switched fixed TDMA wireless networks. The TSRP scheme is based upon two key ideas. The first one is for the system to have more than one coexisting reuse pattern in the time domain. The second is to match a terminal or application to an appropriate reuse pattern, so as to guarantee the required quality of service (QoS). We define and then simulate a specific implementation of the TRSP scheme for an integrated voice and broadband data system. The results show that this scheme provides good performance for both voice and data.