bluuebunny/crossref_metadata_2025_split huggingface dataset:
WirelessATM
Authors: Passas Nikos , Merakos Lazaros 
Published: November 2003

AbstractThis paper discusses the challenges and proposals for combining wireless communications and Asynchronous Transfer Mode (ATM). ATM is considered the most suitable transport technique for the Broadband Integrated Services Digital Network (B‐ISDN), due to its ability to flexibly support a wide range of services. On the other hand, wireless local area networks (LANs) are enjoying a large growth, providing increased transmission speed and reliable communication. The combination of wireless LANs and ATM aims at providing freedom of mobility with service advantages and quality‐of‐service guarantees. The paper studies two main areas of research in wireless ATM: i) advanced medium access control protocols, able to provide adequate support to ATM traffic classes, and ii) signaling enhancements for the support of mobility related operations, such as (de)registration, handover, location update, etc.
Threshold Decoding
Authors: Wu William W. , Massey James L. 
Published: November 2003

Abstract
A fairly comprehensive review is given of threshold decoding from its inception in the 1960s to the present time. Both forms of threshold decoding, namely majority decoding and APP decoding, are based on orthogonal parity checks. The construction of linear block codes and convolutional codes for threshold decoding is treated. The connection between self‐orthogonal codes and perfect difference sets is explained. Examples are used copiously throughout.
Speech Recognition
Authors: Billa Jayadev 
Published: November 2003

AbstractThe ease at which humans use speech understates the complexity of speech recognition for machines. The fundamental difficulty with speech recognition is the overwhelming variation in the production of speech. An automatic speech recognition system must successfully address this variability in speech before any useful output can be provided to the user. Typical automatic speech recognition systems use sophisticated mathematical models, Hidden Markov Models, to build a catalogue of speech features. These models, along with models of language grammar and structure, are used to recognize an incoming speech signal into its most likely word sequence.Today, speech recognition systems are increasing deployed in areas where automation provides both convenience and cost savings. Key problems such as the ability to recognize speech in a variety of environments and over different speaking styles prevent the widespread use of speech recognition technology. In the future, solutions to these problems and others will pave the path for many new and exciting uses and applications of speech recognition.
Minimum‐Shift‐Keying
Authors: Simon Marvin K. 
Published: November 2003

AbstractAmong the many bandwidth efficient constant envelope modulation schemes that fall in the class of continuous phase frequency modulations, minimum‐shift‐keying is undoubtedly the most popular of the group that transmit binary information. The reason for this stems perhaps from the fact that MSK can be viewed both from the standpoint of frequency modulation and pulse‐shaped offset quadrature phase‐shift‐keying thereby allowing a large degree of flexibility in the design of transmitter and receiver implementations. In this chapter we explore a large variety of these implementation options with emphasis on their analytical characterization as well as their power and bandwidth performance behaviors. While the chapter attempts to cover a large body of the published literature on MSK, it is not offered to the readership as an all‐inclusive treatise on the subject but rather one that highlights the key technical contributions that are essential to a basic understanding of the modulation method as well as its associated demodulation, detection, and synchronization techniques.
Linear Predictive Coding
Authors: El‐Jaroudi Amro 
Published: November 2003

AbstractMost real‐world signals carry redundant information from one sample (or snapshot) to the next. The focus of this article is on the use of LP in redundancy removal or data compression for coding applications (also known as linear predictive coding (LPC)). The remainder of the article is organized as follows: LP is formulated and the optimal prediction parameters are derived; the computational aspects and algorithms for the implementation of LP are explored; examples and applications of LPC are presented, and finally, variations on LPC used for coding speech signals are discussed.
Speech Coding: Fundamentals and Applications
Authors: Hasegawa‐Johnson Mark , Alwan Abeer 
Published: November 2003

AbstractIn this chapter, we present an overview of the most widely used algorithms, standards, and applications of wideband and narrowband speech coding. Algorithms for speech coding are classified into four broad headings: (1) waveform coding techniques (including PCM, companded PCM, and DPCM), which are typically used for landline telephony, internet telephony, and secure military communications; (2) subband coding, including perceptually transparent multi‐rate and embedded coding which is mainly used for internet and digital audio applications; (3) linear predictive analysis by synthesis coding (LPC‐AS) algorithms, including multipulse LPC, CELP, SELP, VSELP, and low‐delay CELP, which are typically used for digital cellular and telephony; and (4) LPC vocoders, including advanced vocoder algorithms (e.g., MELP, MBE, and PWI) are used for applications such as secure telephony and satellite telephony. Applications in areas such as voiceover IP (VoIP) and digital cellular are emerging and require a speech coder to gracefully adapt to rapidly changing channel conditions—a need that is met by embedded and multirate speech coders associated with joint source‐channel coding algorithms. Measures of speech coder perceptual quality include subjective measures of intelligibility (DRT and DALT) and naturalness (MOS and DAM), as well as objective measures such as segmental SNR, Bark spectral distortion, PSQM, and PESQ. Speech coding standards are set by organizations including the ITU (for landline telephony), MPEG (for multimedia applications), ETSI (for European digital cellular), TIA (for U.S. digital cellular), and DDVPC (for United States military applications).
BCH
Codes—Binary*
Authors: Michelson Arnold M. , Levesque Allen H. 
Published: November 2003

Abstract
Binary BCH codes are described as a subclass of cyclic codes. The required mathematical background is presented first ‐ finite fields, extension fields, and certain properties of polynomials defined over finite fields. Cyclic codes are introduced using the notion of the generator polynomial and BCH codes are defined in terms of the roots of the generator polynomial. Encoding and decoding of binary BCH codes are discussed and algorithms for both hard‐ and soft‐decision decoding are considered.
Optical Couplers
Authors: Keiser Gerd 
Published: November 2003

Abstract
Optical couplers are used in wavelength division multiplexing (WDM) applications for combining and separating wavelength channels, tapping off power for monitoring purposes, or adding and dropping specific wavelengths at a particular point in an optical fiber communication link. Most optical couplers are passive devices in the sense that they do not need to be powered externally to perform their function on optical signals. Fundamentally, optical couplers connect three or more fibers to combine, split, or redirect light signals. The key optical coupler performance parameters include insertion loss, excess loss, and crosstalk between channels.
Survivable Optical Internet
Authors: Mouftah Hussein T. , Ho Pin‐Han 
Published: November 2003

AbstractThe optical fiber communications with the densewavelength division multiplexing(DWDM) technology have been well recognized as a solution to the ever‐increased bandwidth demand by the versatile multimedia applications foreseeable in the future. The issue ofsurvivability, on the other hand, plays a key role on whether the communication systems can meet the requirements for service continuity. This article is an introduction to the state‐of‐the‐art of theoptical Internetwith a special emphasis on the issue ofsurvivability. A general survey over the evolution of architectural design for protection, and the sketches of implementing restoration algorithms, are provided with detailed discussions and heuristic examples.
Optical Sources
Authors: Buus Jens 
Published: November 2003

AbstractThis article describes the development and the start of the art of optical sources for use as transmitters in fiber optic based communication systems. The evolution of optical sources is described starting from basic laser physics, semiconductor properties, and the transmission characteristics of optical fibers. This includes LEDs and simple laser structures, fixed wavelength single frequency lasers, wavelength selective lasers and tunable lasers.
Optical Filters
Authors: Poladian Leon 
Published: November 2003

Abstract
Optical filters are devices that introduce a wavelength dependent change into the amplitude or phase of an optical signal. The perform many of the functions required in wavelength division multiplexed (WDM) networks: they manipulate, combine, change and reroute information based on the wavelength of light. The most important classes of optical filters are Fabry‐Perot and Mach‐Zehnder interferometers, bulk diffraction gratings, thin‐film stacks, arrayed waveguide grating routers and Bragg gratings. Wavelength selective filters are used as optical demultiplexers, add/drop filters, switches and narrow wavelength mirrors. Wavelength corrective filters are used as amplifier gain‐flattening filters and as dispersion compensators.
Communication System Traffic Engineering
Authors: Kakaes Apostolos K. 
Published: November 2003

Abstract
In order to investigate the traffic engineering problem we begin with a study of the arrival process statistics. We then analyze the most common models used in traffic engineering: the Erlang B model, followed by the Erlang C and the Poisson models. We elaborate on these three models, individually and collectively. Finally, we discuss the problem of random‐access.
Adaptive Equalizers
Authors: Wesołowski Krzysztof 
Published: November 2003

AbstractThe paper considers the problem of adaptive equalization. After introduction of the system model and explanation of the phenomenon of intersymbol interference observed on many communication channels, the equalizer structures and algorithms are classified. Then, linear equalizers are considered, concentrating on Zero‐Forcing (ZF), Mean Square Error (MSE) and Least Squares (LS) adaptation algorithms. Subsequently, the choice of a reference signal and fast linear equalizers using periodic test signals are described. Next, the symbol‐spaced equalizer with the fractionally‐spaced equalizer is compared, showing performance superiority of the latter. The operation of the decision feedback equalizer (DFE) is explained in the next section. Subsequently, more complicated than a DFE, non‐linear equalization structures are described such as those based on the Maximum a Posteriori Probability (MAP) symbol‐by‐symbol detection and the Maximum Likelihood (ML) sequence estimation. Equalizers for trellis‐coded signals are also considered. The last part of the paper is devoted to blind adaptive equalizers and their algorithms. The Bussgang algorithms, the algorithms using the second‐order statistics of the received signal and the probabilistic algorithms are shortly characterized.
Serially Concatenated Codes and Iterative Algorithms
Authors: Benedetto S. , Montorsi G. 
Published: November 2003

Abstract

A serially concatenated code with interleaver consists of the cascade of an
outer
encoder, an interleaver permuting the outer code word bits, and an
inner
encoder whose input words are the permuted outer code words. Decoding is performed by an iterative technique based on two soft‐input soft‐output algorithms tailored to the trellis of the outer and inner encoders. The iterative algorithm can be easily extended to other forms of concatenation, where one or both encoders are replaced with system modules with some form of memory performing different functions, like a modulator, a channel with intersymbol interference, a multiuser combiner. In this paper, we give upper bounds to the
average
maximum‐likelihood error probability of serially concatenated block and convolutional coding schemes. Then, we present design guidelines for the outer and inner encoders that maximize the
interleaver
gain and the asymptotic slope of the error probability curves, describe the iterative decoding algorithm, and, finally, propose extensions to different schemes.
Spatiotemporal Signal Processing in Wireless Communications
Authors: Hatzinakos Dimitrios , Pacheco Ryan A. 
Published: November 2003

Abstract
Spacetime diversity can significantly enhance the performance of wireless communication systems. In this chapter we highlight the potential benefits, requirements and limitations of such systems. In the first half we provide a general treatment of the spacetime signal processing scenario and spacetime diversity and coding frameworks based on block spacetime codes. In the second half, a semiblind signal processing approach is presented and integrated with spacetime diversity and coding to form a realistic scenario for detection and estimation. Our aim is to illustrate the basic priciples and to suggest a realistic approach for implementation of spacetime wireless transcievers.
Streaming Video
Authors: Cohen Robert A. , Radha Hayder 
Published: November 2003

AbstractThe streaming of video over networks has become an important technology as the uses of networks such as the Internet have expanded beyond the exchange of just text and picture‐based information. The purpose of this article is to give an overview of the basic elements and concepts used within a videostreaming system. After describing the concept of videostreaming, we review the components that make up the basic server/client architecture of a video streaming system. We then give details on how video data is prepared for streaming, which include some of the technologies used for compression, rate scalability, and packetization. Next, we cover network‐related aspects such as session control, buffer and delay issues, and congestion control. We end with a summary of the new challenges that are being addressed by researchers and developers of today's videostreaming solutions.
Intranets and Extranets
Authors: Pakštas Algirdas 
Published: November 2003

AbstractIntranets and extranets are types of networks which are based on the internet protocols (TCP/IP, HTTP, etc.). Article describes features of these networks and compares them with intergroupware. Examples of extranet applications are given. Open application standards are described in more detail. Network security issues are considered and a role of security policy is emphasized. Various schemes of applying encryption are described. Special attention is devoted to the secure Virtual Private Networks (VPNs) and use of tunnels for eanbling VPNs. Cost issues related to running of the Web‐site and various methods of remote access (ISDN, mobile) are considered. Example of the estimate for the cost of down time is given. Intranet and extranet trends are presented.
Wirelessad hocNetworks
Authors: Haas Zygmunt J. , Deng Jing , Liang Ben , Papadimitratos Panagiotis , Sajama S. 
Published: November 2003

AbstractA mobile ad hoc network is a relatively new term for an old technology ‐ a network that does not rely on pre‐existing infrastructure. Roots of this technology could be traced back to the early 1970s with the DARPA PRNet and the SURAN projects. The new twitch is the application of this technology in the non‐military communication environments. Additionally, the research community has also recently addressed some extended features of this technology, such as multicasting and security. Also numerous new solutions to the “old” problems of routing and medium access control have been proposed. This survey attempts to summarize the state‐of‐the‐art of the ad hoc networking technology in four areas: routing, medium access control, multicasting, and security. Where possible, comparison between the proposed protocols is also discussed.
Wireless Packet Data
Authors: Balachandran Krishna , Budka Kenneth , Luo Wei 
Published: November 2003

AbstractWireless packet data is defined as transfer of information over radio links that are shared dynamically by multiple users without dedicating wireless resources to individual users during periods of inactivity. In this article, we provide an overview of wireless packet data. Important system aspects, such as system architecture, protocol stacks, system requirements, performance metrics and technology methods are discussed.
LEOSatellite Networks
Authors: Henderson Thomas R. 
Published: November 2003

AbstractIn this article, we survey the main system parameters for multi‐satellite communications networks, highlighting features distinguished from those of geostationary satellites. We first describe various non‐geostationary orbits and popular multi‐satellite constellation designs at low‐Earth‐orbit (LEO). Next, we contrast the differing characteristics of geostationary and non‐geostationary satellite systems, including link performance, tracking and link handoff issues, spectrum and interference concerns, and intersatellite communications links. Finally, we focus on networking aspects of satellite constellations, discussing various circuit‐switching and packet‐switching network architectures that have been proposed in the research literature.
Serially Concatenated Continuous‐Phase Modulation with Iterative Decoding
Authors: Moqvist Pär , Aulin Tor 
Published: November 2003

AbstractSerially concatenated continuous phase modulation (SCCPM), or coded and interleaved CPM, is examined. Like turbo codes, SCCPM allows for iterative decoding based ona posterioriprobability algorithms. The system is analyzed through an upper bound on the average bit error probability with maximum likelihood sequence detection, showing that SCCPM is capable of providing interleaver gain ‐ and thus turbo‐like performance ‐ if a proper mapping of the CPM symbols is used. Simulations indicate that firstly, the analysis gives a satisfactory view of system performance when equal outer codes are used, and secondly, that remarkably good performance can be obtained with some simple systems. For unequal outer codes, the convergence of the iterative decoder will also have a significant effect on performance. Finally, a bandwidth/performance comparison of some selected systems shows that SCCPM can achieve large gains compared to the best known coded CPM systems without interleaving.
IMT
‐2000 3
G
Mobile Systems
Authors: Cerboni Anne , Charles Jean‐Pierre , Ghandour Pierre , i Tresserres Josep Sole 
Published: November 2003

Abstract
IMT‐2000 mobile systems are designed to provide wireless communication services including moving pictures, graphics, sound, and data to people on all continents. While standardization work has made significant strides to achieve a high degree of universality, IMT‐2000 in fact covers a family of standards. This article discusses the relevant standards issues and their implications in different regions. The migration paths from existing mobile systems toward 3G systems are reviewed. The enhanced data rates offered by IMT‐2000 are expected to provide a broad range of mobile multimedia services on a multiple choice of terminals. These new facilities and applications are examined. IMT‐2000 radio access and core network architecture is addressed, as are the most salient economic implications of migration toward 3G, with emphasis on license costs and new business models. The authors conclude with a discussion of beyond 3G evolution, which involves not only an all‐IP core network, but also optimization of scarce spectral resources through cooperation among heterogeneous networks.
Turbo Trellis‐Coded Modulation (TTCM) Employing Parity Bit Puncturing and Parallel Concatenation
Authors: Robertson Patrick , Wörz Thomas 
Published: November 2003

AbstractIn this contribution we explain the principles of Turbo Trellis Coded Modulation (TTCM), a bandwidth efficient channel coding scheme that has an overall structure similar to binary Turbo codes but employs Trellis Coded Modulation (TCM) as component codes. The combination of Turbo codes with powerful bandwidth efficient component codes leads to a straightforward encoder structure and allows iterative decoding in analogy to the binary Turbo decoder. However, certain special conditions are to be met at the encoder, and the iterative decoder needs to be adapted to the decoding of the component TCM codes and to the puncturing used in the code construction. We present simulation results for TTCM schemes for 8‐PSK, 16‐QAM and 64‐QAM modulation schemes with varying overall bandwidth efficiencies. These results show that TTCM is very powerful yet of modest complexity since simple component codes are used. Because TTCM relies onpuncturedTCM component codes, search results based on the best minimal distance of these punctured component codes are also presented. In the Appendix we summarize the derivation of the symbol‐by‐symbol component decoder; the reader will also find implementation guidelines based on processing in the logarithmic domain as well as a number of online and traditional references.
Network Traffic Modeling
Authors: Devetsikiotis Michael , Fonseca Nelson L. S. 
Published: November 2003

Abstract

Telecommunication networks are built to carry “traffic” in the form of data being transmitted. Efforts in network design, control or management require decisions and optimization actions that in turn require traffic
models
. This is why the science and “art” of traffic modeling has been playing a crucial role in the area of communication network design and operation. Traffic modeling has an analytical aspect, whereby suitable stochastic models are devised, and attributed to different types of data sources and network types; and a computational aspect where actual parameter values are estimated from measured data.

In this article, the most common models used in network traffic modeling are presented and basic concepts on traffic characterization are provided. Models for individual traffic sources as well as for aggregates of sources are also introduced. Finally, a brief discussion on the state‐of‐the art and on future trends is presented.
DMT
Modulation
Authors: Schur Romed , Pfletschinger Stephan , Speidel Joachim 
Published: November 2003

Abstract
Due to the enormous growth of telecommunication services during the last decade, the need for a modulation technique that can transmit reliably high data rates with high band‐width efficiency arises. In this context, multicarrier modulation schemes have become very popular for wireless, mobile as well as fixed networks. A well known applications is digital subscriber line (DSL) communication over wired media using the discrete multitone (DMT) modulation scheme.
In this article we present the principles of DMT modulation. We start from the basics of analogue and digital transmission and consecutively develop the main concepts of DMT, as there are: the incorporation of the discrete Fourier transform (DFT) into the modulation scheme, the use of the guard interval to combat interference, the principle of the generalized Nyquist theorem for perfect reconstruction of the signal, the cost‐effective equalization and the adaptive bit‐loading scheme.
Synchronous Optical Network (
SONET
) and Synchronous Digital Hierarchy (
SDH
)
Authors: Freeman Roger 
Published: November 2003

Abstract
SONET and SDH are similar digital transport formats that were developed for the specific purpose of providing a reliable and versatile digital structure to take advantage of the higher bit rate capacity of optical fiber. The objective of this article is to provide an overview of these two standards and some of their challenging innovations that make them interesting, such as the payload pointer.