bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstrip Patch Arrays
Authors: Waterhouse R. B. , Ghorbani K. 
Published: November 2003

AbstractIn this paper a summary of microstrip patch array technology is presented. A variety of fixed beam linear and planar microstrip patch arrays, including design cases, as well as phased arrays incorporating this form of printed antenna are examined. It is shown that microstrip patches are a very versatile style of antenna and can be readily integrated into a multitude of arrays. The complexity of these arrays depends on the degree of control of the radiation performance that is required. Microstrip patch antennas are a cost effective solution to many wireless communication applications and will continue to be utilized in these systems for many years to come.
Antenna Arrays
Authors: Sahalos John N. 
Published: November 2003

AbstractAn attempt is made to describe antenna arrays. The fundamental theory of the array factor and the appropriate indices are described. Linear arrays with uniform binomial and Chebyshev excitations are presented. Planar, rectangular and circular as well as 3‐D and conformal arrays are outlined. Pattern synthesis for uniform and Chebyshev arrays is explained. Array design procedures by sampling or by root matching of Taylor and Bayliss line sources are analyzed. In the pattern synthesis Fourier transform, Woodward‐Lawson (WL) and orthogonal methods are included. Matrix methods, simplex and gradient methods simulated annealing and genetic algorithms are formalized for the design of antenna arrays systems. Antenna arrays combined with signal processing, known as smart antennas, are also discussed. Mutual coupling of the array elements is presented and array feeds are shown for various antenna arrays. Applications and examples as well as appropriate references are included in most of the above topics.
Digital Audiobroadcasting
Authors: Bauer Rainer 
Published: November 2003

AbstractThese days, the use of digital communication techniques is becoming more and more common. While wireline and mobile personal communication services have already taken the step from analog to digital, audio broadcasting is still at the beginning of the digital age. The first part of this article motivates the need for digital audio broadcasting (DAB) and summarizes the advantages of digital transmission compared to analog techniques. The second part sketches different approaches in digital audio broadcasting, both systems which are already in operation today and systems which are about to be introduced in the near future. Finally Eureka‐147 DAB, which has been adopted by many countries worldwide, is described in more detail as an example for an existing digital audio broadcasting system.
Antenna Modeling Techniques
Authors: Volakis John L. , Eibert Thomas F. 
Published: November 2003

Abstract
Antennas are the basic devices which transition an electronic signal within the wired network to an electromagnetic wave that travels through space for possible reception by a corresponding receiving system. They are consequently essential components of any wireless communication system, and the recent rapid growth in consumer wireless devices also resulted in high demand for new antennas satisfying a variety of specialized electrical performance (gain, bandwidth, radiation patterns, etc.) as well as structural and material requirements (size, shape, etc.). Computational techniques play an increasingly more significant role in the design of antennas for commercial as well as military applications and in this chapter we discuss the most popular frequency domain methods for antenna analysis. The standard integral equation and finite element methods are described along with hybrid techniques which combine finite element, integral and high frequency approaches for efficient analysis of antennas in isolation and in presence of the mounting platforms. Example simulations are also given to demonstrate the capability of recent analysis methods for narrowband(wire and patch) and broadband(spiral) antennas in isolations and on full‐scale aircraft.
Ultrawideband Radio
Authors: Siwiak Kazimierz (Kai) , Huckabee Laura L. 
Published: November 2003

AbstractUltra WideBand (UWB) signaling is a modern wireless technique whereby very short baseband signals are transmitted and received without a radio frequency (RF) carrier. This technique re‐uses previously allocated RF bands by spreading the impulse energy thinly in a wide spectrum, thus rendering signals imperceptible in the noise floor of conventional narrow band receivers. There are several methods of generating and radiating UWB signals, including a “low duty cycle UWB” implemented as Time‐Modulated UWB™ (TM‐UWB™), and a high duty cycle “direct sequence phase coded UWB” (DS‐UWB). Unique ways of coding and positioning the impulses, as in Transmitted‐Reference Delay hopped UWB (TRD‐UWB), can result in the efficient raking of the indoor multipath energy. Here, the technological basics and performance of time position coded impulse UWB, the direct sequence coded UWB, and the transmitted reference UWB approaches are explained. Applications of UWB devices are presented and potential uses of UWB are described. Short pulse, low power techniques have enabled practical through‐the‐wall radars, centimeter precision 3‐D positioning, and communications capabilities at the high data rates, all with exceptional spatial capacities.
Digital Phase Modulation and Demodulation
Authors: Xiong Fuqin 
Published: November 2003

Abstract

Digital phase modulation is a class of power‐ and bandwidth‐efficient modulations widely used in telecommunications. In this article, the reader will first be introduced to the general concept of digital phase modulation, and the notions of bandwidth and power efficiency. The commonly used class of digital phase modulation schemes, that is,
M
‐ary phase shift keying (MPSK), are described in detail. Their signal waveform expressions, signal constellations, and power spectral densities (PSDs) are presented. The block diagrams of the modulator and the optimal coherent demodulator are presented and explained. The symbol and bit error rate (BER) of the demodulator is derived and symbol error probability graphs are given. Widely used binary PSK (BPSK) and quaternary PSK (QPSK) are treated as special cases of MPSK. Next, differential PSK schemes are introduced, which are particularly useful in wireless fading channels. Their symbol error probability expressions and graphs are presented. At the end, two important phase modulation variations, namely, offset QPSK (OQPSK) and π/4‐DQPSK, and the advanced continuous‐phase modulation (CPM), including multi‐
h
CPM, are briefly introduced.
Adaptive Antenna Arrays
Authors: Kim Kyungjung , Sarkar Tapan K. , Palma Magdalena Salazar 
Published: November 2003

AbstractConventional adaptive techniques generally deal with antenna arrays that consist of omni directional isotropic radiating elements uniformly spaced. When the uniformity in the spacing is relaxed one then needs multiple snapshots in estimating the complex amplitude of the signal of interest (SOI) arriving from a known direction in the presence of multipaths, clutter and thermal noise. Usually a statistical methodology is used for the adaptive process which makes it difficult to incorporate the various electromagnetic effects like mutual coupling between the elements, presence of near field scatterers and so on and obtain a real time solution in a dynamic environment where the interference scenario may change from snap shot to snap shot.The object of this article is to present an adaptive methodology that can not only deal with realistic antenna elements operating in a real environment but can also handle the effects of mutual coupling between the antenna elements. In addition, one can incorporate in this methodology the effects of near field scatterers and use of dissimilar antenna elements in the array. The analysis is carried out by using a dynamic electromagnetic analysis tool. In addition, an array transformation technique is used to mitigate the various complex electromagnetic effects in a non‐uniformity spaced nonplanar array in the presence of the mutual coupling and transform the problem to that of a virtual linear array of uniformly spaced omni directional isotropic point radiators operating in free space. The preprocessed data from the interpolated virtual array is analyzed using a direct data domain least squares approach utilizing a single snapshot of data to estimate the strength of the signal of interest arriving from a known direction in the presence of coherent strong jammers, clutter and thermal noise. In addition, this methodology is quite amenable to real time processing.Thus this adaptive methodology is split into two parts. First one uses an electromagnetic analysis tool in conjunction with an interpolation algorithm to transform the induced voltages in the real antenna elements due to the presence of mutual coupling and near field scatterers to that of a virtual array containing isotropic omni directional point radiators. Then a direct data domain least square method is applied to the pre processed data to obtain the desired signal strength in the presence of strong interferers, clutter and thermal noise. Numerical results are represented to illustrate the efficiency and accuracy of this method. No attempt has been made to cite the earlier references; the bibliography provides a list where supplemental information may be available.
ALOHA
Protocols
Authors: Metzner John J. 
Published: November 2003

Abstract
ALOHA protocols deal with largely uncoordinated packet transmissions by multiple senders, where the senders all learn of success or collision via a common feedback channel. Slotted ALOHA involves sending fixed‐size packets in random time slots. Unslotted ALOHA involves sending variable‐size packets at any starting time. The article provides a brief analysis of ALOHA efficiency and stability, and explains some modifications to ALOHA that improve these properties. The improvements include collision resolution algorithms, reservation ALOHA, multichannel ALOHA, capture ALOHA, multibase ALOHA, and nonbinary ALOHA. Also discussed is the use of ALOHA with a time constraint and CDMA‐related spread ALOHA.
Wideband
CDMA
in Third‐Generation Cellular Communication Systems
Authors: Mark Jon W. , Zhu Shihua 
Published: November 2003

Abstract
ITU, the international wireless standards body, has adopted both IMT‐2000 (European) and CDMA‐2000 (North American) as multiple access technologies for 3G air interface. IMT‐2000 is direct‐sequence wideband CDMA, while CDMA‐2000 is multi‐carrier CDMA. Of relevance are the transmission and reception issues in the physical layer and resource management issues in the link layer. This article describes and discusses the IMT‐2000 network architecture and the associated signaling mechanisms as a 3G air interface for service support using wideband DS‐CDMA as multiple access strategy. To combat channel impairments, IMT‐2000 uses a combination of channel coding and spectrum spreading. To circumvent the need for stringent synchronization, IMT‐2000 uses two‐layer spreading: orthogonal codes for channelization in the first layer and non‐orthogonal codes for scrambling in the second layer. For the downlink, every base station in the cellular system uses the same set of Hadamard codes or orthogonal variable spreading factor codes as its channelization codes, while each cell uses a cell‐specific Gold code as its scramble code.
Scalar and Vector Quantization
Authors: Kaukoranta Timo 
Published: November 2003

AbstractScalar quantization is a basic technique for analog‐to‐digital signal transformation. It has an extensive theoretical background in addition to the practical usefulness. Vector quantization offers very good possibilities for lossy signal compression. The method has the great advance that its decoding runs extremely fast. Unfortunately, it includes other complexity problems such as the construction of the codebook, the search of the nearest reproduction vector, and the storage of the codebook. This work describes the basic properties of quantization and introduces several vector quantization structures briefly. Most common methods for codebook construction are described also.
Iterative Detection Methods For Multiuser Direct‐SequenceCDMASystems
Authors: Rasmussen Lars K. 
Published: November 2003

AbstractIn this paper, the fundamental principles behind iterative multiuser detection are presented. Such strategies are also known as iterative interference cancellation. Cancellation structures can be constructed in a systematic manner, using an interference cancellation unit. The inter‐connection of such units decides the specific cancellation strategy, whether cancellation is done serially, in parallel or as a combination of the two. The unit itself is characterized by a tentative decision function. In this paper we particularly focus on four different tentative decision functions and provide theoretical background. The considered decision functions are the linear, hard, clipped linear, and hyperbolic tangent functions, respectively. The concept of weighted cancellation is also presented and explained. Selected numerical examples are included to illustrate the characteristic convergence behavior and bit error rate performance.
Geosynchronous Satellite Communications
Authors: Lee Lin‐Nan , Karimullah Khalid 
Published: November 2003

Abstract
In this article, we discuss the development of the geosynchronous satellite concept. We explore frequency bands and orbital slots, satellite antenna beam patterns, transmission techniques, multiple‐access techniques and onboard processing. Also included is a discussion of satellite communications system equipment. We conclude with a section on GEO satellite system link budgets.
Signature Sequences forCDMACommunications
Authors: Ottosson Tony , Ström Erik , Svensson Arne 
Published: November 2003

AbstractCode‐division multiple accessis a method allowing several users to share a common physical channel. Different users use differentsignature sequencesfor their messages. The signature sequences and the channel determine theinterferencebetween different users in the receiver and the performance of the synchronization method used, and thus the signature sequences represent an important part of the multiple access method. In this article, an overview of code‐division multiple access is presented and properties of signature sequences are discussed. Some common classes of signature sequences are described and their properties are summarized. Some remarks on the difficulty in designing signature sequences are also given at the end.
Spread Spectrum Signals for Digital Communications
Authors: Proakis John G. 
Published: November 2003

Abstract
Spread spectrum signals is a class of signals that were designed primarily for use in digital communication systems to overcome either intentional or unintentional interference. We begin by illustrating the basic elements of a spread spectrum digital communication system. Next, we consider the transmission of a binary information sequence by means of binary PSK. Later, we discuss frequency‐hopped (FH) spread spectrum. Finally, we close with a section on commercial spread spectrum systems.
cdma
2000
Authors: Corazza Giovanni Emanuele , Vanelli‐Coralli Alessandro 
Published: November 2003

Abstract
cdma2000 is the multicarrier wideband code‐division multiple access (CDMA) radio interface included in the International Mobile Telecommunications‐2000 (IMT‐2000) family of standards. The cdma2000 radio interface has been developed within the Third Generation Partnership Project 2 (3GPP2). The multicarrier structure pertains strictly to the forward link baseline configuration, where three adjacent direct‐sequence spread RF carriers are used, while in the reverse link a single direct‐spread RF carrier is adopted. cdma2000 is backward compatible with the TIA/EIA‐IS‐95‐B standard, also known as cdmaOne. The article introduces the role of cdma2000 within IMT‐2000, the 3GPP2 organization, and the general characteristics of the standard. It then describes in detail the air interface protocol architecture, in terms of physical layer, medium access control layer, link access control layer, upper signaling layer, and system procedures. Finally, the key features of the cdma2000, also in comparison with other 3G CDMA air interfaces, are summarized.
Wireless Sensor Networks
Authors: Megerian Seapahn , Potkonjak Miodrag 
Published: November 2003

Abstract
Sensor networks consist of a set of sensor nodes, each equipped with one or more sensors, communication subsystems, storage and processing resources, and in some cases actuators. The sensors in a node observe phenomena such as thermal, optic, acoustic, seismic, and acceleration events, while the processing and other components analyze the raw data and formulate answers to specific user requests. Recent advances in technology have paved the way for the design and implementation of new generations of sensor network nodes, packaged in very small and inexpensive form factors with sophisticated computation and wireless communication abilities. Although still at infancy, these new classes of sensor networks, generally referred to as wireless sensor networks (WSN), show great promise and potential with applications ranging in areas that have already been addressed, to domains never before imagined. In this article we provide an overview of this new and exciting field and a brief discussion on the factors pushing the recent flurry of sensor network related research and commercial undertakings. We also provide overview discussions on architectural design characteristics of such networks including physical components, software layers, and higher level services. At each step, we highlight special characteristics of WSNs and discuss why existing approaches and results from wireless communication networks are not necessarily suitable in WSN domains. We conclude by briefly summarizing the state of the art and the future research directions.
Wireless Application Protocol (
WAP
)
Authors: Andreadis Alessandro , Giambene Giovanni 
Published: November 2003

Abstract

The
Wireless Application Protocol
(WAP) is the result of the WAP Forum's efforts for allowing mobile users to access easily the Internet. WAP contains a lightweight protocol stack (based on the Internet one) well suited for the wireless scenario. It also includes an application environment for the development of user applications, allowing the delivery of information services to mobile phones. A review of the protocol stack and system architecture is provided here together with some aspects related to the tools to develop WAP applications.
Multimedia Over Digital Subscriber Lines
Authors: Zheng Haitao , Liu K. J. Ray 
Published: November 2003

Abstract
The purpose of the chapter is to examine multimedia communications systems in the context of joint source channel optimization. The key to the design of high‐performance multimedia communications systems is the ability to perform efficient resource allocation. The characteristics of source traffic raise a wider variety of channel design and configuration issues. The traffic generator should plan source traffic flow wisely to make intelligent use of channel resources. The channel designer should have the ability to adjust transmission design and configuration according to source traffic characteristics. In this chapter, we explore this joint design concept in ADSL by comparing two transmission architectures and their associated resource allocation procedures. The study indicates that the characteristics of both multimedia traffic and ADSL transmission channel can be jointly utilized to provide efficient resource usage.
Bandwidth Reduction Techniques for Video Services
Authors: da Fonseca Nelson L. S. 
Published: November 2003

AbstractA single videostream requires a considerable amount of bandwidth. Considering a potential population of several million viewing households, the network bandwidth demand would be beyond the present‐day network capacity. Such a demand prevents the deployment of VoD on a large scale. In this paper, techniques for the reduction of the bandwidth demand of video services are presented. The techniques discussed here are: piggybacking, patching, batching, and periodic broadcasting.
Channel Tracking in Wireless Communication Systems
Authors: Bottomley Gregory E. , Arslan Hüseyin 
Published: November 2003

AbstractChannel estimation is an integral part of standard adaptive receiver designs used in digital wireless communication systems. In this article, commonly used approaches to channel tracking are reviewed, including both filtering and recursive approaches. These approaches are based on approximate models of how the channel response changes with time. Both reference‐assisted (pilot symbols, pilot channel) and data‐directed channel tracking are considered. Applications include second and third generation digital cellular communication systems, which employ time‐division multiple‐access (TDMA) or direct‐sequence code‐division multiple‐access (DS‐CDMA).
Optical Transport System Engineering
Authors: Cvijetic Milorad 
Published: November 2003

Abstract
The fundamentals of optical transport system engineering are introduced in this article. Optical transport system engineering is related to the physical layer of an optical network, and takes into account the optical signal propagation length, characteristics of optical elements used (optical fibers, lasers, optical amplifiers, photodiodes, etc.), modulation bit rate, networking impact and transmission requirements. The article involves accounting for different impairments that degrade and compromise the integrity of an optical signal on its way from the source (semiconductor laser) on through photodetection by photodiode, and to the decision point, where it is recovered from corruptive additives (noise, crosstalk, and interference.)
Constrained Coding Techniques for Data Storage
Authors: Coene Wim M. J. , Hollmann Henk D. L. 
Published: November 2003

AbstractModulation codes such as runlength‐limited codes have been widely employed in magnetic and optical data storage systems. We review the main techniques involved in the design and use of these codes: the maximal code rate or capacity, graphical presentations of constraints, encoders and decoders, and code construction methods such as the ACH state‐splitting algorithm. We conclude this survey by discussing some recent developments and research trends.
Interference Modeling in Wireless Communications
Authors: Yang Xueshi , Petropulu Athina P. 
Published: November 2003

AbstractIn wireless communication networks, signal reception is often corrupted by interference from other sources that share the same propagation medium. Knowledge of the statistics of interference is important in achieving optimum signal detection and estimation. We here discuss statistical‐physical models for modeling interference. The interesting feature of these models is that they are non‐Gaussian, and in certain cases are heavy‐tail distributed. The latter property introduces several challenges in the analysis of interference, since heavy‐tail processes lack second‐order statistics. A introduction on heavy‐tail processes is also provided.