Showing papers on "Broadband networks published in 1998"

Wideband DS-CDMA for next-generation mobile communications systems

Abstract: Wideband wireless access based on direct sequence code division multiple access aimed at third-generation mobile communications systems is reviewed. W-CDMA is designed to flexibly offer wideband services which cannot be provided by present cellular systems, with various data rates as high as 2 Mb/s. The important concept of W-CDMA is the introduction of intercell asynchronous operation and the pilot channel associated with individual data channels. Intercell asynchronous operation facilitates continuous system deployment from outdoors to indoors. Other technical features of W-CDMA include fast cell search under intercell asynchronous operation, fast transmit power control, coherent spreading code tracking, a coherent RAKE receiver, orthogonal multispreading factor forward link, and variable-rate transmission with blind rate detection. The introduction of the data-channel-associated pilot channel allows W-CDMA to support interference cancellation and adaptive antenna array techniques that can significantly increase the link capacity and coverage. This article presents the radio link performance evaluated by computer simulation. Field experiment radio link performance results are also presented.

UMTS/IMT-2000 based on wideband CDMA

Abstract: The UMTS terrestrial radio access is based on wideband 4.096 Mchip/s DS-CDMA technology. UTRA will be connected to an evolved GSM core network for both circuit and packet services. A merger between ETSI/Europe and ARIB/Japan based on W-CDMA, a GSM core network, and a common frequency allocation according to the ITU Recommendation of 2 GHz makes a global IMT-2000 standard feasible. UTRA based on W-CDMA fully supports the UMTS/IMT-2000 requirements (e.g., support of 384 kb/s for wide-area coverage and 2 Mb/s for local coverage). Furthermore, the air interface has flexible support of mixed services, variable-rate services, and an efficient packet mode. Key W-CDMA features also include improved basic capacity/coverage performance compared to second-generation systems, full support of adaptive antenna arrays, support of hierarchical cell structures with interfrequency handover, and support of asynchronous inter-base-station operation. There have been no constraints due to the strong requirements for backward compatibility with second-generation systems. This has facilitated a high degree of flexibility and a future-proof air interface. Extensive evaluations by means of simulations and field trials have been carried out by a number of companies, and full system tests are ongoing. Consequently, W-CDMA technology can now be regarded as a mature technology, ready to provide the basis for UMTS/IMT-2000.

Communication system for providing broadband data services using a high-voltage cable of a power system

Abstract: A communication system is disclosed for providing broadband multimedia services using one or more high-voltage cables of a power distribution network, while the power distribution network is supplying electrical power. A radio-frequency signal at a first location is coupled to the high-voltage cable, transported over the high-voltage cable, and then coupled from the high-voltage cable at a second location. The radio-frequency signal at the first location is modulated with information and demodulated at the second location, thereby providing broadband multimedia service between the two locations. The broadband multimedia communications system may be used for a variety of communication needs, such as telephone service, video service, internet service, and other services requiring high-speed data transfers.

A novel impulse radio network for tactical military wireless communications

Abstract: Two of the major concerns in tactical military wireless communication networks are covertness and throughput. Impulse radio is an ultra-wideband code division multiple access (UWB-CDMA) technique being considered as the physical layer for future networks. Impulse radio exhibits low power spectral density and relatively high immunity to fading but suffers from relatively long acquisition times. In traditional packet radio networks (PRNs), the physical layer link is terminated while scheduling half-duplex transmissions or in the absence of data packets. To re-establish physical layer links in an impulse radio system, signaling packets containing exceptionally long acquisition headers transmitted at higher powers are required. Hence, to improve covertness in an impulse radio based network, we propose a MAC layer scheme we call sustained link networks (SLN) where the physical layer links are maintained continuously. We develop a full-duplexing scheme which takes advantage of the low duty cycle nature of impulse radio to maintain physical layer links capable of supporting bi-directional data transfer. During the periods between data bursts, the physical layer links are maintained by transmitting supplementary data at low bit rates and low power levels. We quantify the performance of an impulse radio receiver implementing the full-duplex scheme developed. We also present performance comparisons of an SLN based on impulse radio with traditional PRN variations implemented using impulse radio.

Broadband traffic modeling: simple solutions to hard problems

Abstract: A much clearer picture of the progress toward an integrated high-speed multiservice network is now emerging. Such networks were anticipated over 20 years ago, at a time when packet switching was just another way to transmit data. Now the technology is so mature that media barons are organizing their investments in order to take advantage of its profitability. Many of the technical problems are now solved, and the fundamental protocols required for these networks are sufficiently well-defined to support a rapidly expanding industry. However, consensus on how to talk about the statistics of the data transmitted around these networks has not been readily forthcoming. Nevertheless, there now exists a family of models with sufficient richness to describe real traffic fairly well, which can be parameterized conveniently, and which degenerates to a readily analyzable Gaussian model in the situation of very large networks. This analysis leads to important architectural conclusions which accord with common sense, in particular the conclusion that integrated networks of the future should be able to provide better and better service with efficiency tending toward perfection. This is a rather happy conclusion which thoroughly confirms the current rapid drive toward an all-encompassing integrated multiservice network. Rather than the increase in traffic and diversity of service types leading to greater and greater complexity, it seems that the flow of traffic in our networks may become steadily more manageable.

A millimeter-wave full-duplex fiber-radio star-tree architecture incorporating WDM and SCM

Abstract: We propose a full-duplex millimeter-wave fiber-radio network for providing wireless customer access to broadband services. It consists of a hybrid star-tree architecture connecting remote antenna base stations to a central control office (CO) by incorporating wavelength-division multiplexing (WDM) of the optical signals and subcarrier multiplexing (SCM) of the radio signals. These multiplexing schemes allow the sharing of equipment at the CO and therefore enable a simple radio distribution architecture to be implemented. We also demonstrate a 35.5-39.5-GHz full-duplex fiber-radio star-tree network, featuring three WDM carriers in the downstream and a single carrier in the upstream. Each downstream wavelength carries three 155-Mb/s BPSK SCM channels between 35.8-39.3 GHz, while a 37-GHz carrier transports 51.8 Mb/s upstream.

Telecommunications Network Planning

Abstract: From the Publisher: Telecommunications Network Planning will benefit both telecommunications practitioners looking for efficient methods to solve their problems and operations researchers interested in telecommunications. The book examines network design and dimensioning problems; it explores Operation Research issues related to a new standard Asynchronous Transfer Mode (ATM); it overviews problems that arise when designing survivable SDH/SONET Networks; it considers some broadband network problems; and it concludes with three chapters on wireless and mobile networks. Leading area researchers have contributed their recent research on the telecommunications and network topics treated in the volume.

Wide-area current differential backup protection employing broadband communications and time transfer systems

Abstract: As power systems grow larger, it is becoming difficult to achieve reach and time coordination in backup protection when using distance relays. To cope with those problems, current differential backup protection for a busbar and transmission circuits connected to that busbar on an inter-station or wide-area basis is proposed. The proposed system can operate better than conventional systems with respect to operation time, section selectivity, etc. A system configuration is also proposed to utilize ATM transmission networks and time synchronous systems which make the construction and operation of the proposed wide-area protection system easy and flexible.

Joint coding and decision feedback equalization for broadband wireless channels

Abstract: This paper introduces a new approach for joint convolutional coding and decision feedback equalization (DPE). To minimize error propagation, the DFE uses a combination of soft decisions and delayed tentative decisions to cancel intersymbol interference (ISI). Soft decisions are obtained by passing the DFE output through a (soft) nonlinear device. This simple method is shown to perform almost as well as an optimum soft feedback approach on wireless channels with diversity. Tentative decisions from the Viterbi decoder are used to cancel ISI due to multipath with large delays, thus remedying the increasing effect of error propagation in channels with large delay spreads. We consider the use of this soft/delayed feedback DFE (S/D-DFE) technique in broadband wireless channels (with delay spreads up to several tens of the symbol period) typical in high-bitrate mobile data applications. Simulation results indicate that the proposed joint coding and S/D-DFE technique performs to within 1-2 dB [in required signal-to-noise ratio (SNR)] of an ideal coded DFE without error propagation. When combined with antenna diversity and a reduced-complexity DFE concept with adaptive feedforward tap assignment, it provides high packet throughput against Rayleigh fading, severe delay spreads, and high Doppler rates.

Network for providing switched broadband multipoint/multimedia intercommunication

Abstract: The present invention provides broadband multimedia communication over the standard circuit-switched public switched telephone network infrastructure (PSTN) and other physical or virtual circuit-switched infrastructures while simultaneously and transparently interoperating with the public Internet packet-switched infrastructure to effectively merge the capabilities of the two types of infrastructures into a seamless capability that can bring the benefits of using both types of existing switching infrastructures to large groups of users under the control of the same common and simple interface tools such as web browsers. The invention enables users to establish both packet-switched connections for sending or receiving content for which low-latency and unpredictable response times are not a problem (i.e. text, small graphics, e-mail, small file transfers); and circuit-switched connections for sending or receiving content that benefits from streaming data at fixed data rates, without contention for bandwidth from other users during a communication session, (i.e. video, voice, complex graphics and animations, or large file transfers). The broadband network of the present invention thus mates the convenience of point-and-click on-demand Internet-type packet-switched connectivity with the continuity of a circuit-switch connection, and bundles B channels, or controls connections on virtual circuit switches such as ATM or RSVP for the required bandwidth on-demand for video conferencing and other high-bandwith applications.

Broadband spectrum surveys in Denver, CO, San Diego, CA, and Los Angeles, CA: methodology, analysis, and comparative results

Abstract: The Institute for Telecommunication Sciences (ITS) has performed a set of automated, broadband measurement surveys of spectrum usage in several metropolitan areas in the United States across the frequency range 108 MHz to 19.7 GHz. The methodology, hardware and software used to conduct the surveys are described. The survey results are broken down into separate categories for mobile, point-to-point and radiolocation bands. In mobile bands, maximum, minimum and average levels of usage during the survey periods are measured. Relatively light usage by terrestrial point-to-point microwave systems is observed. Broadband occupancy at relatively levels is shown for radar systems in the radiolocation bands.

Evolutionary-fuzzy prediction for strategic QoS routing in broadband networks

Abstract: We present an application of evolutionary-fuzzy prediction in inter-domain routing of broadband network connections with quality of services requirements in the case of an integrated ATM and SDH networking architecture. The higher-layer nature of inter-domain routing requires us to review the whole routing process in order to maximize performance at low decision making cost, a clear case for fuzzy-set logic based algorithms. In order to probabilistically avoid shortage of resources, besides effectively computing the feasible paths for an incoming connection request, under uncertainty, these paths should be compared in terms of the negative impact in resource supply which may be caused by other connections. To do this, besides enriching the protocol with vectors of per-class shadow cost metrics, quantized using fuzzy-set theory, we used a subset-interactive autoregressive time-series predictor which is based on fuzzy measures to evaluate path costs under supply metrics that change over time. Moreover, as the connections we are dealing with are semi-permanent, we must take into account the connections lifetime. The complete system is part of the MISA (Management of Integrated SDH and ATM) network architecture and will be implemented and evaluated in the global broadband connection service of the pan-European test-bed.

Emerging wireless broadband networks

Abstract: The rapid evolution of mobile wireless access networks toward multimedia support with QoS provision forces the development of advanced wireless broadband systems with high reliability and high data rate. To achieve this goal, new system design concepts with increased system capacity will be required. In that context, ATM is becoming a major infrastructure, receiving a lot of attention for telecommunication systems since ATM networks can most effectively support wireless access systems. Wireless ATM systems have low transmission cost, flexible functionality, mobile ATM protocol, and radio access layer protocols. This article overviews the various wireless broadband systems studied at 5, 19.37, 40, and 60 GHz by European Union funded projects within the ACTS program. Moreover, related standardization activities and network evolution are also addressed.

Radio resource allocation in fixed broadband wireless networks

Abstract: We consider use of fixed broadband wireless networks to provide packet services for telecommuting and Internet access. Each cell is divided into multiple sectors, each of them served by a sector antenna colocated with the base station (BS), and user terminals also use directional antennas mounted on the rooftops of homes or small offices and pointed to their respective BS antennas. To support a target data rate of 10 Mb/s, a bandwidth of several MHz is required. Since radio spectrum is expensive, the bandwidth needs to be reused very aggressively. Thus, efficient strategies for frequency reuse and managing cochannel interference are critically important. We propose several algorithms for dynamic radio-resource allocation in the fixed wireless networks. In particular, a method to be referred to as the staggered resource allocation (SRA) method uses a distributed scheduling algorithm to avoid major sources of interference while allowing concurrent packet transmission and meeting signal-to-interference objectives. The performance of the method is studied by analytic approximations and detailed simulation. Our results show that the combination of directional antennas plus the SRA method is highly effective in controlling cochannel interference. For reasonable system parameters, the SRA method delivers a throughput in excess of 30% per sector while permitting a given frequency band to be reused in every sector of every cell. It also provides satisfactory probability of successful packet transmission. In addition, a simple control mechanism can be applied in the method to improve performance for harsh radio environments.

System at telecommunications network

Abstract: A system provides interactive control of broadband services. There are today systems which offer distributive services, for instance analog cable-TV, analog satellites and acting terrestrial TV-networks. A paradigm shift, however, has been initiated in connection with that digital transmissions have started, which make possible a more spectrum efficient transmission. This means, for instance, that a broadband service such as digital transmission of video channels can be developed by making it interactive. One solution can be to use the GSM-system. For example, services which require low capacity in uplink can utilize the SMS-function is GSM. At larger demand of bandwidth GSM's data services can be utilized, which however prevents calls when the telephone is used for interactive communication. The invention solves this problem by interactive traffic between the transmitting and receiving equipment being managed by an interactive center (IC) which is arranged to execute wanted broadband service. IC in addition is in connection with a distributive centre (DC) for distribution of the broadband signals out on the telecommunications network.

Low-power equalizer architectures for high speed modems

Abstract: In many DSP-based high-speed modem applications, such as broadband modems for high-speed Internet access to the home or gigabit Ethernet transceivers, channel equalization requires processing power so high that power consumption and clock speed become major design challenges. This article describes techniques to implement low-cost adaptive equalizers for ASIC implementations of broadband modems. Power consumption can be reduced using a careful selection of architectural, algorithmic, and VLSI circuit techniques. The derivation of a hybrid FIR filter structure is given that enables the designer to adjust both the speed and power consumption to suit an application. Furthermore, the architecture can be made programmable to target multiple applications in one piece of silicon while maintaining or even improving the efficiency of the architecture. Run-time techniques are shown that can minimize the power consumption for a given application or operating environment. In all cases, the power reduction techniques are supported by simulations and measurements made on a test integrated circuit.

A proposal for an RLC/MAC protocol for wideband CDMA capable of handling real time and non-real time services

Abstract: In this paper we describe a proposal for a radio link control/medium access control (RLC/MAC) protocol for a W-CDMA system It makes use of the flexibility offered by the physical layer in the sense that it supports variable bit rate services In addition the RLC/MAC is designed such that multiple services are supported, without the necessity to transmit with multiple spreading codes

Performance evaluation of connection rerouting schemes for ATM-based wireless networks

Abstract: Supporting mobility in asynchronous transfer mode (ATM)-based broad-band networks with wireless access links poses many technical challenges. One of the most important of these challenges is the need to reroute ongoing connections to/from mobile users as these users move among base stations. Connection rerouting schemes must exhibit low handoff latency, maintain efficient routes, and limit disruption to continuous media traffic while minimizing reroute updates to the network switches. In this paper we propose, describe an implementation for, and experimentally evaluate the performance of five different connection rerouting schemes. We show that one of these schemes, which operates in two phases, executes very fast reroutes (with a measured latency of 6.5 ms) in a real-time phase and, if necessary, reroutes again in a nonreal-time phase to maintain efficient routing. The scheme also results in negligible disruption to both audio (e.g., a 1-in-100 chance of a single packet loss at CD-quality audio rates of 128 kb/s) and low-bit-rate video (e.g., a 2-in-100 chance of a single packet loss for 1-Mb/s video) traffic during connection rerouting. Based on these results, we conclude that simple handoff schemes coupled with a connection management architecture are sufficient for supporting low-bit-rate continuous media applications over ATM-based wireless networks.

Minimum overhead burst synchronization for OFDM based broadband transmission

Abstract: In this paper the subject of training data overhead in burst oriented transmission systems using OFDM is addressed. Previous work has shown that burst synchronization for such scenarios is possible. However, the training data needed in some cases will significantly decrease the usable bandwidth. In order to minimize overhead we analyze the impact of synchronization errors on OFDM and derive a suitable optimization criterion. A novel training data format is introduced that allows to tailor the overhead according to the actual requirements. Using theoretical analysis and simulation the training data overhead can be decreased significantly without loss in performance.

Broadband any point to any point switch matrix

Abstract: This invention is a broadband matrix switch system and method of operation The broadband matrix switch has N number of broadband inputs, each of the broadband inputs having one or more broadband signals The matrix switch has M number of broadband outputs There are N number of splitters Each of the splitters has a splitter input connected to one of the broadband inputs Each of the splitters has M number of splitter outputs that produce the splitter output signal There are N times M number of node switches Each node switch is uniquely connected to one of the splitter outputs The node switches have a control input that allows the node switch to pass the respective splitter output signal upon receiving a close command at the control input and to terminate the respective splitter output signal with an input impedance upon receiving an open command at the control input There are M number of combiners Each combiner has a combiner output connected to one of the broadband outputs Each combiner further having N number of combiner inputs Each of the combiner inputs are connected to one and only one of the inputs through the respective splitter and node switch The node switches terminate the combiner input with an output impedance upon receiving an open command The matrix switch further has a controller that sends one or more open commands to selected node switches to connect one or more of the broadband inputs to one or more of the broadband outputs The matrix switch has many uses in switching and monitoring and analyzing broadband networks, for example, cable TV networks

Millimeter waves for short-range multimedia communication systems

Abstract: A framework for the performance characterization of short-range communications systems is developed with the intention of investigating the feasibility of new multimedia wireless services at millimeter waves (MMWs). Both narrow- and wide-band systems are considered for mobile and/or fixed users. This paper aims at defining and evaluating proper metrics to characterize the service quality for the user and jointly takes the propagation characteristics, the transmission techniques, and the multiple access protocols into account. The definition of service-oriented metrics is emphasized. Three different real scenarios operating at MMW are investigated with a unified perspective: intelligent transport systems, wide-band local-area networks, and local multipoint distribution systems for interactive video services. The role played by the MMW band in the development of these services is discussed. In each scenario, accurate propagation analysis is carried out and suitable countermeasure techniques are pointed out in order to join suitable service-quality levels. The methodology considered is based on both analytical and semianalytical tools for performance evaluation.

Regional and far-regional earthquake locations and source parameters using sparse broadband networks: A test on the Ridgecrest sequence

Abstract: Events of the 1995 Ridgecrest, California, earthquake sequence were located and source parameters were estimated using data recorded by the broadband, high-dynamic-range instrumentation of the Berkeley Digital Seismic Network (BDSN). The purpose of this study is to investigate the capability of a sparse broadband network at monitoring a region located outside of the network, as will be the case in the monitoring of the Comprehensive Test Ban Treaty (CTBT) for low-magnitude seismic events. In addition, we present a case study that is representative of the capabilities of other regional broadband networks. To assess the capability of a sparse network, we compared locations estimated from BDSN phase measurements to a “ground truth” catalog of high-quality earthquake locations derived from data recorded by the Southern California Seismic Network (SCSN). An adaptive grid search location program that utilizes the timing and azimuth of multiple-phase picks from one or more stations was used to determine the importance of the different types of data on absolute event locations. Sparse subnets of BDSN stations in the distance ranges from 250 to 500 km and 500 to 800 km were used. The results indicate that in the regional distance range, it is possible to obtain absolute event locations to within 18 km as is prescribed by the CTBT; however, in the far-regional distance range, the lower signal-to-noise levels precluded the location of the events to within the CTBT objective.

A dynamic programming methodology for managing prerecorded VBR sources in packet-switched networks

Abstract: Broadband networks will increasingly carry prerecorded traffic, such as high-fidelity audio, short multimedia clips, and full-length movies. We study how to manage the transmission and transport of traffic from prerecorded VBR sources so that network resources are efficiently utilized and end users receive satisfactory service. Specifically, we study Piecewise Constant-Rate Transmission and Transport (PCRTT), whereby the server transmits and the network transports each connection's packets at different constant rates over a small number of intervals. We show how Dynamic Programming (DP) can be applied to find optimal PCRTT rates and intervals for a wide variety of optimization criteria, including criteria which explicitly account for delays to user interaction (pause, fast forward, and rewind). We also introduce two admission policies for PCRTT: peak-rate admission and packing admission. For peak-rate admission, for each video the network allocates an end-to-end CBR connection; the rate of the CBR connection is equal to the maximum PCRTT rate. For packing admission, for each video the network reserves a series of CBR connections of different rates over specific time intervals. Using public domain MPEG traces, we present several numerical examples which illustrate the traffic management schemes and the DP methodology.

A dynamic quality of service framework for video in broadband networks

Abstract: A dynamic framework for QoS control of video in distributed multimedia applications is presented. The framework allows flexible and efficient video delivery with application-level QoS support. Key components of the framework are client QoS renegotiation, server source rate control, and dynamic bandwidth allocation. The coordinated functionality of these distributed components provides soft QoS to adaptive applications. A proof-of-concept prototype of a video browser with user-level control of soft QoS is implemented within the proposed framework. The implementation uses a distributed software architecture that represents soft QoS requirements by software objects called service contracts. These objects are exchanged among servers, network nodes, and clients to achieve distributed soft QoS control. Experiences with the prototype and its performance are discussed.

Method and system for provisioning a single physical broadband drop to accommodate multiple devices

Abstract: A method and system for allowing a plurality of devices at a physical drop to receive access to video and/or data services from a plurality of video/data service providers in a digital broadband network serviced by a telecommunication services provider utilizes a broadcast manager, in communication with the video/data service providers, for transmitting an electronic message in a modified format determined by the telecommunication services provider, wherein the electronic message contains information identifying the physical drop, a type of the device being provisioned a the physical drop, and a maximum number of devices for the device type allowed to receive corresponding service at the physical drop. A broadband digital terminal, in communication with the broadcast manager and the physical port, is programmed to receive the electronic message and store the corresponding information. Upon receiving a sign-on request from a requesting device that is requesting access to one of the video and data services, the broadband digital terminal determines whether the requesting device is authorized to access the requested video or data service based on the stored information.

TCP for high performance in hybrid fiber coaxial broad-band access networks

Abstract: Motivated by the phenomenal growth of the Internet in recent years, a number of cable operators are in the process of upgrading their cable networks to offer data services to residential subscribers, providing them direct access to a variety of community content as well as to the Internet. Using cable modems that implement sophisticated modulation-demodulation circuitry, these services promise to offer a several hundredfold increase in access speeds to the home compared to conventional telephone modems. Initial experiences indicate that cable networks are susceptible to a variety of radio-frequency (RF) impairments that can result in significant packet loss during data communication. In the face of such losses, the transmission control protocol (TCP) that is predominantly used by data applications degrades dramatically in performance. Consequently, subscribers of broad-band data services may not perceive the projected hundredfold increase in performance. We analyze the performance of TCP under different network conditions using simulations and propose simple modifications that can offer up to threefold increase in performance in access networks that are prone to losses. These modifications require only minor changes to TCP implementations at the local network servers alone (and not at subscribers' PCs).

Traffic shaping, bandwidth allocation, and quality assessment for MPEG video distribution over broadband networks

Abstract: This article provides an overview of residential video delivery systems and presents the applications, benefits, and challenges of using VBR MPEG video encoding in broadband video distribution networks. The network resources required to transmit stored variable-rate MPEG can be reduced by properly analyzing and smoothing the video stream before transmission. A scheduling technique is presented which selects a traffic contract for a pre-encoded MPEG video stream with the criteria of minimizing network resources and maintaining video quality. Several effective bandwidth metrics are discussed and used to model the potential savings in network resources for the shaped streams.

A novel broadband all-wireless access network using stratospheric platforms

Abstract: This paper proposes a novel broadband access network using a number of stratospheric platforms. This is a new wireless infrastructure, and consists of wireless access links between the platform and terminals in the Ka-band and a mesh-like network using optical inter-platform links. One platform covers a 40 km/spl times/40 km area with 64 beams of an onboard multi-beam antenna. Thus, the cell size is almost as same as that of current cellular systems. This network can provide 25 Mbps to more than 156 Mbps access links and a flexible wireless ATM network to subscribers.

Broadband millimeter-wave fiber-radio network incorporating remote up/downconversion

Abstract: A high capacity full-duplex millimeter-wave fiber-radio network which incorporates remote up and downconversion is demonstrated. This technique minimizes fiber dispersion-induced phase noise, allowing higher-order modulation formats to be incorporated which increase network capacity and spectral efficiency. Remote up and downconversion also enables lower cost components to be employed throughout the network.

Application and evaluation of large deviation techniques for traffic engineering in broadband networks

Abstract: Accurate yet simple methods for traffic engineering are important for efficient dimensioning of broadband networks. The goal of this paper is to apply and evaluate large deviation techniques for traffic engineering. In particular, we employ the recently developed theory of effective bandwidths, where the effective bandwidth depends not only on the statistical characteristics of the traffic stream, but also on a link's operating point through two parameters, the space and time parameters, which are computed using the many sources asymptotic. We show that this effective bandwidth definition can accurately quantify resource usage. Furthermore, we estimate and interpret values of the space and time parameters for various mixes of real traffic demonstrating how these values can be used to clarify the effects on the link performance of the time scales of burstiness of the traffic input, of the link parameters (capacity and buffer), and of traffic control mechanisms, such as traffic shaping. Our approach relies on off-line analysis of traffic traces, the granularity of which is determined by the time parameter of the link, and our experiments involve a large set of MPEG-1 compressed video and Internet Wide Area Network (WAN) traces, as well as modeled voice traffic.