Download or read book Analysis of Large Area Synchronous Code Division Multiple Access LAS CDMA written by Stephen A. Brooks and published by . This book was released on 2002-06-01 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large area synchronous code-division multiple access (LAS-CDMA) is a proposed fourth generation cellular standard, Similar to cdma2000, the distinguishing feature of LAS-CDMA is the new set of spreading codes used to separate users in the wireless channel, This thesis examines the properties of the new spreading codes, Unlike Walsh functions, which are orthogonal only when perfectly synchronized, LAS-CDMA spreading codes are orthogonal when synchronized within a nine-chip interference-free time window, The interference- free time window allows LAS-CDMA to transmit the forward link and reverse link over the same frequency band, The primary LAS-CDMA data channels are examined LAS-CDMA uses a separate set of modulation and coding rate combinations for voice and data communications Analysis of the effect of a tone jammer on the modulation and coding rate combinations is presented, Also, the ease with which LAS-CDMA can be intercepted is examined, and the security of LAS-CDMA is analyzed.
Download or read book Code Division Multiple Access CDMA written by R. Michael Buehrer and published by Morgan & Claypool Publishers. This book was released on 2006 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the basic aspects of Code Division Multiple Access or CDMA. It begins with an introduction to the basic ideas behind fixed and random access systems in order to demonstrate the difference between CDMA and the more widely understood TDMA, FDMA or CSMA. Secondly, a review of basic spread spectrum techniques are presented which are used in CDMA systems including direct sequence, frequency-hopping and time-hopping approaches. The basic concept of CDMA is presented, followed by the four basic principles of CDMA systems that impact their performance: interference averaging, universal frequency reuse, soft handoff, and statistical multiplexing. The focus of the discussion will then shift to applications. The most common application of CDMA currently is cellular systems. A detailed discussion on cellular voice systems based on CDMA, specifically IS-95, is presented. The capacity of such systems will be examined as well as performance enhancement techniques such as coding and spatial filtering. Also discussed are Third Generation CDMA cellular systems and how they differ from Second Generation systems. A second application of CDMA that is covered is spread spectrum packet radio networks. Finally, there is an examination of multi-user detection and interference cancellation and how such techniques impact CDMA networks. This book should be of interest and value to engineers, advanced students, and researchers in communications.
Download or read book Design and Analysis of a Dynamic Space code Multiple Access with Large Area Synchronous Scheme Using the Smart Antenna System written by Chee Kyun Ng and published by . This book was released on 2007 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most important property in wireless system, when it comes to increase the system capacity and spectrum efficienc, is eliminating interference. Code Division Multiple Access (CDMA) is considered interference-limited system. Spatial filtering using smart antenna has emergerd as a promising technique to improve the performance of cellular communication systems; hence, Space Division Multiple Access (SDMA) has recently received increasing interest in improving the performance of wireless systems. These interference interest in improving the performance of wireless systems. These interference-limited systems are susceptible to time of arrival (TOA) and angle of arrival (AOA) of individual user signals, thus, a non-uniform traffic can severely degrade the performance of CDMA and SDMA systems. In this thesis, new approach of the joint multiple access system from the combining of CDMA and SDMA systems is designed, and its system performances are then investigated. An innovative approach to eliminate the existing interferences in this joint multiple access system is proposed. The spreading sequences of Large Area Synchronous Even Ternary (LAS-ET) which exhibited an interference free window (IFW) in their correlation are exploited here. The spatial signature from smart antenna narrower beam is exploited to drive all the multipath propagation to arrive within the IFW in reverse link transmission. The size of IFW is adaptable with the size of smart antenna beamwidth through dynamic space code (DSC) algorithm. Hence, this double signatures scheme forms a novel multiple access scheme called Dynamic Space Code Multiple Access (DSCMA) system. From the nature of spatial filtering of smart antenna systems, a dynamic sequence reuse assignment is possible in DSCMA to increase its spectrum efficiency. The non-zero pulse intervals and sequence length of LAS-ET are arranged in even numbers which has demonstrated some performance improvements in ternary phase shift keying (TPSK) signalling. On the other hand, the combined spreading sequence and spatial signature scheme also prompts a possibility of developing a novel Space Division Duplexing (SDD) scheme. The reverse and forward links are transmitted within a narrower beam of smart antenna, and both links are distinguished by different LAS-ET sequences. The simulation results indicate that the reverse link system capacity in DSCMA using LAS-ET spreading sequences together with smart antenna system is increased dramatically compared to traditional binary spreading sequences. The results also showed that the spectrum efficiency of DSCMA is increased when the number of elements in smart antenna system is increased. Finally, it can be concluded that the system capacity and spectrum efficiency are increased significantly from DSCMA using smart antenna due to its perfect interference cancelation scheme.
Download or read book Performance Analysis of Direct Sequence Code Division Multiple Access Communications with Asymmetric Quadrature Phase Shift Keying Modulation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-04 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.Wang, C.-W. and Stark, W.Jet Propulsion LaboratoryQUADRATURE PHASE SHIFT KEYING; BINARY PHASE SHIFT KEYING; ASYMMETRY; CODE DIVISION MULTIPLE ACCESS; PHASE SHIFT KEYING; MULTIPLE ACCESS; PROTECTION; RELIABILITY ANALYSIS
Download or read book Temporal spatial Optical Code division Multiple Access CDMA Network design Analysis and Experimental Demonstration written by Eugene Park and published by . This book was released on 1991 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis and Simulation of a Direct Sequence code Division Multiple Access DS CDMA System with Averaged Diversity Code Combining written by Shuling Feng and published by . This book was released on 1997 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Coherent Random carrier CDMA and Hybrid WDMA CDMA Multiplexing for High capacity Optical Networks written by Behzad Ghaffari and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper provides an accurate analysis of the performance of a random-carrier (RC) code-division multiple-access (CDMA) scheme recenily introduced for use in high-capacity optical networks. According to this scheme coherent optical techniques are employed to exploit the huge bandwidth of single-mode optical fibers and are coupled with spread spectrum direct-sequence modulation in order to mitigate the interference from other signals due to the frcquency overlap caused by the instability of the carrier frequency of the laser, or to the mistakes in the frequency coordination and assignment. The average bit error pmbability of this multiplexing scheme is evaluated by using the characteristic function of the other-user interference at the output of the matched optical filter. Both phase noise and thermal noise (AWGN) are taken into account in the computation. Both synchronous and asynchronous Systems are analyzed in this context. The analysis is valid for any spreading gain and any number of interfering users and makes very limited use of approximations. The performance evaluation of RC CDMA establishes the potential advantage in employing hybrids of WDMA (wavelength-division multiple-access) and CDMA multiplexing to combat inter-carrier interference in dense WDMA systems.
Download or read book Analysis of Coherent Random carrier CDMA and Hybrid WDMA CDMA Multiplexing for High capacity Optical Networks written by Behzad Ghaffari and published by . This book was released on 1989 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OFDM and MC CDMA written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2007-01-11 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless communications has witnessed a tremendous growth during the past decade and further spectacular enabling technology advances are expected in an effort to render ubiquitous wireless connectivity a reality. Currently, a technical in-depth book on this subject is unavailable, which has a similar detailed exposure of OFDM, MIMO-OFDM and MC-CDMA. A further attraction of the joint treatment of these topics is that it allows the reader to view their design trade-offs in a comparative context. Divided into three main parts: Part I provides a detailed exposure of OFDM designed for employment in various applications Part II is another design alternative applicable in the context of OFDM systems where the channel quality fluctuations observed are averaged out with the aid of frequency-domain spreading codes, which leads to the concept of MC-CDMA Part III discusses how to employ multiple antennas at the base station for the sake of supporting multiple users in the uplink By providing an all-encompassing self-contained treatment this volume will appeal to a wide readership, as it is both an easy-reading textbook and a high-level research monograph.
Download or read book Sequences and Their Applications SETA 2010 written by Claude Carlet and published by Springer Science & Business Media. This book was released on 2010-09 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volumecontainstherefereedproceedingsoftheSixth International Conf- ence on Sequences and Their Applications (SETA 2010), held in Paris, France, September 13-17, 2010. The previous ?ve conferences were held in Singapore (RepublicofSingapore),Bergen(Norway),Seoul(SouthKorea),Beijing(China) and Lexington (USA). Topics of SETA include: – Randomness of sequences – Correlation (periodic and aperiodic types) and combinatorial aspects of - quences (di?erence sets) – Sequences with applications in coding theory and cryptography – Sequences over ?nite ?elds/rings/function ?elds – Linear and nonlinear feedback shift register sequences – Sequences for radar distance ranging, synchronization, identi?cation, and hardware testing – Sequences for wireless communication – Pseudorandom sequence generators – Boolean and vectorial functions for sequences, coding and/or cryptography – Multidimensional sequences and their correlation properties – Linear and nonlinear complexity of sequences The Technical Program Committee of SETA 2010 refereed 56 submitted - pers. Each paper was reviewed by at least 2 referees (at least 3 when an author was a TPC member) and the TPC selected 33 papers to be presented at the conference. In addition, we had 4 invited papers, byRobert Calderbank(Prin- ton University, USA), James Massey (retired from ETH Zurich, Switzerland), Jong-Seon No (Seoul National University, South Korea) and Arne Winterhof ¨ (Osterreichische Akademie der Wissenschaften, Austria). TheCo-chairsoftheTPCwereClaudeCarlet(Universit´ eParis8,France)and Alexander Pott (Otto-von-Guericke-Universit¨ at, Magdeburg, Germany). They wish to thank the other members of the ProgramCommittee: Thierry P.
Download or read book Technology Base of Mobile Cellular Operators in Germany and China written by Mingtao Shi and published by Univerlagtuberlin. This book was released on 2007 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Access Nets written by Chonggang Wang and published by Springer. This book was released on 2009-09-29 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: The annual International Conference on Access Networks (AccessNets) aims to provide a forum that brings together researchers and scientists from academia as well as man- ers and engineers from industry to meet and exchange ideas and recent work on all aspects of access networks. AccessNets 2008 was the third edition of this event, which was successfully held in Las Vegas, Nevada, USA, during October 15–17, 2008. The conference consisted of two keynote addresses, five invited talks, seven technical sessions, and two panel sessions. Leonid Kazovsky from Stanford University and Kevin Schneider, Chief Technology Officer of ADTRAN, delivered their exciting keynote - dresses on “Future Evolution of Broadband Access,” and “Carrier Ethernet and the Evo- ing Access Networks,” respectively. Maurice Gagnaire, Martin Reisslein, Martin Maier, Paolo Giacomazzi, and John M. Cioffi gave interesting invited talks on different research topics on access networks. The technical papers presented original and fundamental - search advances in the area of access networks, while the panels focused on the interesting topics of “Fiber Assisted Wireless for Broadband Access Networks and Dynamic Spectrum Management (DSM) Successes. ” These conference proceedings include all the technical papers that were presented at AccessNets 2008. We hope that it will become a useful reference for researchers and practitioners working in the area of access networks.
Download or read book Optical Code Division Multiple Access written by Paul R. Prucnal and published by CRC Press. This book was released on 2018-10-03 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Code-division multiple access (CDMA) technology has been widely adopted in cell phones. Its astonishing success has led many to evaluate the promise of this technology for optical networks. This field has come to be known as Optical CDMA (OCDMA). Surveying the field from its infancy to the current state, Optical Code Division Multiple Access: Fundamentals and Applications offers the first comprehensive treatment of OCDMA from technology to systems. The book opens with a historical perspective, demonstrating the growth and development of the technologies that would eventually evolve into today's optical networks. Building on this background, the discussion moves to coherent and incoherent optical CDMA coding techniques and performance analysis of these codes in fiber optic transmission systems. Individual chapters provide detailed examinations of fiber Bragg grating (FBG) technology including theory, design, and applications; coherent OCDMA systems; and incoherent OCDMA systems. Turning to implementation, the book includes hybrid multiplexing techniques along with system examples and conversion techniques to connect networks that use different multiplexing platforms, state-of-the-art integration technologies, OCDMA network security issues, and OCDMA network architectures and applications, including a look at possible future directions. Featuring contributions from a team of international experts led by a pioneer in optical technology, Optical Code Division Multiple Access: Fundamentals and Applications places the concepts, techniques, and technologies in clear focus for anyone working to build next-generation optical networks.
Download or read book Cellular Communication Networks and Standards written by Wei Jiang and published by Springer Nature. This book was released on with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical Reviews written by and published by . This book was released on 2004 with total page 1078 pages. Available in PDF, EPUB and Kindle. Book excerpt:
