Parallel Acquisition in Code Division Multiple Access Spread Spectrum Systems PDF Download

Author: Roland Reinhard Rick
Publisher:
ISBN:
Category :
Languages : en
Pages : 292

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Author: Savo G. Glisic
Publisher: Springer Science & Business Media
ISBN: 146152251X
Category : Technology & Engineering
Languages : en
Pages : 366

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Book Description
Code Division Multiple Access (CDMA) has become one of the main candidates for the next generation of mobile land and satellite communication systems. CDMA is based on spread spectrum techniques, which have been used in military applications for over half a century. Only recently, however, has it been recognised that spread spectrum techniques, combined with some additional steps, can provide higher capacity and better flexibility for the mobile cellular radio communications. Code Division Multiple Access Communications comprises a set of contributions from the most distinguished world scientists in the field. These papers review the basic theory and some of the most important problems related to spread spectrum and CDMA. The topics covered centre on the information theory aspects of CDMA; interference suppression and performance analysis. The material presented in this book summarises the main problems in modern CDMA theory and practice and gives a solid starting point for studying this complex and still challenging field. As such Code Division Multiple Access Communications is essential reading for all researchers and designers working in mobile communication systems and provides an excellent text for a course on the subject.

Author: Zhiyuan Yan
Publisher:
ISBN:
Category :
Languages : en
Pages : 52

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Author: Meera Srinivasan
Publisher:
ISBN:
Category :
Languages : en
Pages : 214

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Book Description
Parallel search schemes are presented for the acquisition of spreading sequences in chip-asynchronous direct-sequence spread-spectrum communication systems. In a parallel acquisition scheme, an estimate of the delay of a direct-sequence signal is made directly from a number of correlations of the received signal against different shifted versions of the spreading signal. Parallel schemes acquire the signal very quickly, but are more computationally intensive than serial schemes. In this thesis, we investigate several parallel strategies for the acquisition for general binary spreading sequences and develop suboptimal acquisition schemes that are easier to implement than the previously proposed optimal schemes. The techniques presented are attractive in that they approximate the optimal parallel schemes in terms of probability of successful acquisition, but are much easier to implement than the optimal schemes. The single-user phase-coherent situation is considered first. In this case, both carrier frequency and phase are known. We first discuss the optimal and maximum likelihood estimators for general binary spreading sequences and then present two new suboptimal schemes. One of these schemes is a small signal approximation of the optimal scheme, and it performs very well over a large range of signal-to-noise ratio. The other scheme is a hybrid of the optimal and maximum likelihood schemes, and is extremely simple. The hybrid scheme can be analyzed precisely in terms of its probability of unsuccessful acquisition. It is shown that this hybrid scheme has error probability decreasing exponentially with increasing SNR, and that this scheme is practically the simplest possible parallel scheme that has this property. Our result also proves an earlier conjecture that the optimal parallel estimator has error probability that decreases exponentially with increasing SNR. The same approach is used to devise simple acquisition schemes for the single-user noncoherent situation. A locally optimal estimator for low SNR is presented, along with two different noncoherent analogues of the coherent hybrid scheme. One of the noncoherent hybrid schemes is analyzed, and it is shown that this scheme also has exponentially decreasing error probability. This also proves that the error probability of the optimal noncoherent estimator decreases exponentially with increasing SNR. The problem of acquiring several direct-sequence signals in the absence of data modulation is also considered. The chip-synchronous situation is considered first and decorrelating methods are used to develop two near-far resistant strategies. One of these schemes estimates the signal delays in multiple stages, with each delay estimate depending on previous delay estimates, while the other scheme estimates the delays simultaneously and independently of each other. Schemes for the chip-asynchronous case are then developed by combining the coherent hybrid scheme for the single-user situation with the multistage decorrelating method. Monte Carlo simulation is used to obtain the error probabilities for the various schemes.

Author: Khaled Fazel
Publisher: John Wiley & Sons
ISBN: 0470714239
Category : Technology & Engineering
Languages : en
Pages : 384

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Book Description
The technological progress in multi-carrier (MC) modulation led orthogonal frequency division multiplexing (OFDM) to become an important part of beyond 3G cellular mobile communication standards, including LTE and WiMAX. In addition, the flexibility offered by the spread spectrum (SS) and time division multiplexing (TDM) techniques motivated many researchers to investigate several MC combined multiple access schemes, such as MC-CDMA, OFDMA and MC-TDMA. These schemes benefit from the advantages of each sub-system and offer high flexibility, high spectral efficiency, simple detection strategies and narrow-band interference rejection capability. Multi-Carrier and Spread Spectrum Systems is one of the first books to describe and analyze the basic concepts of multi-carrier OFDM transmission and its combination with spread spectrum (MC-CDMA). The different architectures and detection strategies as well as baseband-related transceiver components are explained. This includes topics like FEC channel coding and decoding, modulation and demodulation (IFFT/FFT), digital I/Q-generation, time and frequency synchronisation, channel estimation, frequency domain equalization and RF aspects such as phase noise and non-linearity issues. Concrete examples of its applications for cellular mobile communication systems (B3G/4G) are given. Further derivatives of MC-SS (such as OFDMA, SS-MC-MA and DFT-spread OFDM) and their corresponding applications in the LTE, WiMAX, WLAN and DVB-RCT standards are detailed. Capacity and flexibility enhancements of multi-carrier OFDM systems by different MIMO diversity techniques such as space time/frequency coding (STC, SFC) and software defined radio concepts are also described. Written in a highly accessible manner this book provides a unique reference on the topics of multi-carrier and spread spectrum communications, assisting 4G engineers with their implementation. Fully updated new edition of successful text, including two new chapters on LTE and WiMAX Describes in detail new applications of OFDM in mobile communication standards Examines all multi-carrier spread spectrum schemes, with in-depth analysis, from theory to practice Introduces the essentials of important wireless standards based on multi-carrier/spread spectrum techniques.

Author: Marvin K. Simon
Publisher:
ISBN: 9780881750157
Category : Spread spectrum communications
Languages : en
Pages : 456

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Author: Durgaprasad Kashinath Shamain
Publisher:
ISBN:
Category :
Languages : en
Pages : 330

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Book Description

Author: Amer A. Hassan
Publisher: Springer Science & Business Media
ISBN: 1461555310
Category : Technology & Engineering
Languages : en
Pages : 170

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Book Description
Perspectives in Spread Spectrum brings together studies and recent work on six exciting topics from the spread spectrum arts. The book gives a wide, collective view of trends, ideas, and techniques in the spread spectrum discipline, due to the authors' extensive work on spread spectrum techniques and applications from different vantage points. The inexorable march of electronics towards ever faster, ever smaller, and ever more powerful electronic and optical circuitry has wrought, and will continue to enable, profound changes in the spread spectrum arts, by allowing increasingly complex signalling waveforms and statistical tests to be implemented as the theory beyond spread spectrum continues to evolve. Perspectives in Spread Spectrum is divided into six chapters. The first chapter deals with sequence spreading design. There is not a single metric for design of spreading sequences; rather, the design is ideally tailored to the specific scenario of usage. This chapter delves into recent and very promising synthesis work. The second chapter deals with OFDM techniques. As channels become wider and trans-channel fading (or jamming) becomes frequency selective across the band, OFDM techniques may provide a powerful alternative design perspective. The third chapter is a generalization of the venerable Walsh functions. A new modulation scheme, Geometric Harmonic Modulation, GHM for short, is reviewed and characterized as a form of OFDM. From GHM, a further generalization of the Walsh functions is derived for non-binary signalling. The fourth chapter is concerned with some new and exciting results regarding the follower jammer paradigm. A counter-countermeasure technique is reviewed, notable for its counterintuitive characteristic which can be understood from a simple yet elegant game framework. The fifth chapter recounts some results pertaining to random coding for an optical spread spectrum link. The technique is based on laser speckle statistics and uses a coherent array of spatial light modulators at the transmitter but allows the receiver to be realized as a spatially distributed radiometric and therefore incoherent structure. The sixth and final chapter looks at an important and interesting application of spread spectrum to accurately locate a wideband, ‘bent pipe’, satellite transponder. It is, in a strong sense, an inverted GPS technique. Perspectives in Spread Spectrum serves as an excellent reference and source of ideas for further research, and may be used as a text for advanced courses on the topic.

Author: Richard Poisel
Publisher: Artech House
ISBN: 1608071669
Category : Technology & Engineering
Languages : en
Pages : 895

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Book Description
This edition features a wealth of new material on urban warfare, including a computer simulation of EW architecture alternatives for land-based forces based on urban constraints. It also includes an expanded section on time-hopped spread spectrum communications, more details on modern communication system technologies such as CDMA and OFDM, and an in-depth discussion on sources of urban noise. This practical resource is focused on showing the reader how to design and build jammers specifically targeted at spread spectrum, anti-jam communications. Moreover, it gives assistance in evaluating the expected performance of jamming systems against modern communications systems, and discover the best waveform to use to counter communication systems designed to be effective in jamming environments. While mathematical derivations in general are avoided, the book presents error rate performance equations for most modern digital anti-jam communication systems

Author: Don Torrieri
Publisher:
ISBN: 9781423508052
Category :
Languages : en
Pages : 150

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Book Description
This report presents a detailed analysis of the most important aspects of spread spectrum code division multiple access (CDMA). The foundations are provided to enable the reader to understand the more advanced literature. The fundamental characteristics of a fading channel are summmarized. Various types of diversity and diversity combining are examined. Both direct sequence and frequency hopping systems and networks are analyzed.