Download or read book On the System Level Performance of Mc cdma Systems in the Downlink written by Abdel-Majid Mourad and published by . This book was released on 2006 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: La technique de transmission multi-porteuses à étalement de spectral, MC-CDMA, est un candidat potentiel pour les interfaces radio des futurs systèmes radio mobiles. Cette technique bénéficie d'une part de la robustesse de la transmission multi-porteuses OFDM face à la propagation multi-trajets et d'autre part de la flexibilité de l'accès multiple à répartition par codes CDMA. Cette thèse s'intéresse à l'étude des performances systèmes de la technique MC-CDMA en liaison descendante. L'objectif est de valider au niveau système les concepts et algorithmes de la couche physique MC-CDMA. La thèse s'articule autour de deux thématiques qui sont liées. La première thématique concerne l'abstraction de la couche physique au niveau système. Cette thématique est aussi connue sous le nom d'interfaçage entre les niveaux lien physique et système. L'abstraction de la couche physique a pour principal objectif de définir une mesure adéquate pour prédire la qualité de transmission au niveau système. Dans cette thèse, nous étudions l'abstraction de la couche physique suivant deux échelles de temps. La première échelle est macroscopique et porte sur la transmission de plusieurs trames de données subissant des évanouissements de canal indépendants. D'autre part, la deuxième échelle est dite microscopique et porte sur la transmission d'une seule trame de données subissant un évanouissement particulier du canal. L'abstraction macroscopique est appropriée pour une évaluation des performances systèmes par des simulations systèmes statiques alors que l'abstraction microscopique est plus appropriée pour une évaluation plus précise des performances systèmes ainsi que pour étudier les algorithmes d'adaptation de lien par des simulations systèmes dynamiques. Dans notre étude, nous analysons les problèmes soulevés par les deux types d'abstraction et proposons des nouvelles solutions appropriées.La deuxième thématique concerne l'évaluation de la capacité cellulaire des algorithmes et configurations de la couche physique MC-CDMA. En utilisant l'abstraction macroscopique, nous développons une méthodologie semi-analytique d'évaluation de la capacité cellulaire. L'évaluation de la capacité est faite aussi bien au niveau lien à travers un nouveau indicateur de capacité qu'au niveau système à travers un simulateur statique de type Monte Carlo. La méthodologie développée ici est un outil simple et efficace pour identifier les algorithmes et configurations de couche physique les mieux adaptés pour un environnement donné.

Download or read book OFDM and MC CDMA for Broadband Multi User Communications WLANs and Broadcasting written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2005-01-28 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency-division multiplexing (OFDM) is a method of digital modulation in which a signal is split into several narrowband channels at different frequencies. CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimising the use of available bandwidth. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end. Multi-Carrier (MC) CDMA is a combined technique of Direct Sequence (DS) CDMA (Code Division Multiple Access) and OFDM techniques. It applies spreading sequences in the frequency domain. 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. This technical in-depth book is unique in its 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 Portrays the entire body of knowledge currently available on OFDM Provides the first complete treatment of OFDM, MIMO(Multiple Input Multiple Output)-OFDM and MC-CDMA Considers the benefits of channel coding and space time coding in the context of various application examples and features numerous complete system design examples Converts the lessons of Shannon’s information theory into design principles applicable to practical wireless systems Combines the benefits of a textbook with a research monograph where the depth of discussions progressively increase throughout the book This all-encompassing self-contained treatment will appeal to researchers, postgraduate students and academics, practising research and development engineers working for wireless communications and computer networking companies and senior undergraduate students and technical managers.

Download or read book Multi Carrier Spread Spectrum written by Khaled Fazel and published by Springer Science & Business Media. This book was released on 2006-02-23 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: The benefits and success of multi-carrier (MC) modulation on one side and the flexibility offered by the spread spectrum (SS) technique on the other side have motivated many researchers to investigate the combination of both techniques since 1993. This combination known as multi-carrier spread spectrum (MC-SS) benefits from the advantages of both systems and offers high flexibility, high spectral efficiency, simple detection strategies, narrow-band interference rejection capability, etc. The basic principle of this combination is straightforward: The spreading is performed as direct sequence spread spectrum (DS-SS) but instead of transmitting the chips over a single carrier, several sub-carriers are employed. The MC modulation and demodulation can easily be realized in the digital domain by performing IFFT and FFT operations. The separation of the users’ signals can be performed in the code domain. MC-SS systems can perform the spreading in frequency direction, which allows for simple signal detection strategies. Since 1993, MC-SS has been deeply studied and new alternative solutions have been proposed. Meanwhile, deep system analysis and comparison with DS-CDMA have been performed that show the superiority of MC-CDMA. The aim of Multi-Carrier Spread-Spectrum is to edit the ensemble of the newest contributions and research results in this new field that have been presented during the 5th International Workshop on Multi-Carrier Spread-Spectrum (MC-SS 2005), held in Oberpfaffenhofen, Germany.

Download or read book Chinese well known dishes written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Performance Analysis of Multicarrier CDMA Systems written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research being conducted is designed to yield major improvements in the capabilities of military wireless communications systems. The new system is designed around a physical layer based upon a wideband direct sequence (DS) multicarrier (MC) code division multiple access (CDMA) link. Among other things, an MC signal does not require a contiguous spectrum: this means, for example. that an MC CDMA network can be overlaid upon an existing set of narrowband signals simply by leaving appropriate gaps in the placement of the multiple carriers. Such a characteristic will allow the military to employ the same frequencies as used by various commercial systems, thereby making use of the technology advancements in those frequency bands, and yet not be limited in deployment because of excessive interference from conventional narrowband signals. We have emphasized the effect of estimation errors in determining channel state information for use in optimal receiver design for MC CDMA systems, and have performed analyses of performance. as measured by the average probability of error of the system. We have also included the use of space-time spreading.

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 Multi Carrier and Spread Spectrum Systems written by Khaled Fazel and published by John Wiley & Sons. This book was released on 2008-09-15 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Transmission Strategies Employing Multiple Antennas for TheDownlink of Multi Carrier CDMA Systems written by Thomas Sälzer and published by . This book was released on 2004 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-Carrier CDMA (MC-CDMA) combining multi-carrier modulation and spreading in the frequency domain is a promising candidate for new air interfaces of future mobile radio systems. This thesis explores the potential of multiple antenna technologies for the downlink of an MC-CDMA system. Space-frequency transmit filtering is proposed for the case where instantaneous knowledge of the channel fading is available at the basestation. This approach can optimally exploit the spatial diversity of the channel and efficiently mitigate the multiple access interference. When only covariance knowledge is available, we propose transmit beamforming with direction-based spreading code assignment. This technique benefits from the antenna gain and from an implicit reduction of the interference. Both transmission strategies lead to an increased user capacity and simultaneously allow a transfer of implementation complexity from the mobile terminal to the basestation.

Download or read book Performance Analysis of MC CDMA and CI MC CDMA Using Interference Cancellation Techniques written by Anshul Sharma and published by . This book was released on 2008 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient use of the spectrum is an essential problem in creating any multi-user cellular mobile system. The bandwidth requirements of the future 4G systems far exceed what the existing traditional setup can provide. A more creative utilization of the available bandwidth is more important now than ever before. Improved receiver design that utilizes the frequency and code diversity of the MC-CDMA schemes is one way of increasing the number of users supported at very high bitrates. We discuss the MC-CDMA system operating over a frequency selective, slowly fading channel. We study in detail multiuser Parallel Interference Cancellation detectors employing the MRC and MMSE detectors. Various configurations of the PIC are studied and simulated to evaluate and understand the comparative advantages and disadvantages. In this thesis we offer a review of the literature available on MC-CDMA and CI/MC-CDMA systems. We study the performance of the MRC-PIC-MMSE system both semi-analytically and by computer simulations. By means of computer simulations, we also compare the advantages of using the Carrier Interferometry codes over the Walsh Hadammard codes under various system configurations.

Download or read book Frequency Generalized MC CDMA Systems and Performance Over Multiband Channels and with Multiple Level Orthogonal MLO Codes written by Jingtao Zhang and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Communications and Networking written by Jun Peng and published by IntechOpen. This book was released on 2010-09-28 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book "Communications and Networking" focuses on the issues at the lowest two layers of communications and networking and provides recent research results on some of these issues. In particular, it first introduces recent research results on many important issues at the physical layer and data link layer of communications and networking and then briefly shows some results on some other important topics such as security and the application of wireless networks. In summary, this book covers a wide range of interesting topics of communications and networking. The introductions, data, and references in this book will help the readers know more abut this topic and help them explore this exciting and fast-evolving field.

Download or read book Performance Analysis of a Multi code Multi carrier CDMA Communication System written by and published by . This book was released on 2004 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new wireless communication system denoted as Multi-Code Multi-Carrier CDMA (MC/MC-CDMA), which is the combination of Multi-Code CDMA and Multi-Carrier CDMA, is analyzed in this thesis. This system can satisfy multi-rate services using multicode schemes and multi-carrier services used for high rate transmission. In addition, the new MC/MC-CDMA system is robust against frequency selective fading, is good for narrowband interference rejection, and has higher spectral efficiency. The system is evaluated in Nakagami slow fading channel model, which can be used to model urban and suburban environments. At the receiver, the system employs three diversity schemes; namely, selection diversity, equal gain combining and maximal ratio combining. The improvements of the diversity schemes are analyzed and compared. Also the system performance is presented and compared with that of other systems such as conventional CDMA system, multi-code CDMA system, and multi-carrier CDMA system. In addition, the performance of the system in the presence of a narrow jammer signal is considered and analyzed. Results indicate that the performance of the MC/MC-CDMA system is superior to that of the conventional CDMA, multi-code CDMA and multi-carrier CDMA systems. It is also shown that the MC/MC-CDMA system is suitable for high data rate and multi-rate services.

Download or read book Cellular MC CDMA Downlink Systems written by Simon Plass and published by . This book was released on 2008 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Downlink Performance Analysis of DS CDMA System with Base Station Diversity written by Hemabh Shekhar and published by . This book was released on 2002 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we study the performance of DS-CDMA downlink with base station diversity (BSD), since most of the works till date have concentrated on uplink. A BSD architecture is considered with three base stations (BSs) per cell and its performance compared against the conventional cellular network with one BS per cell. A mobile station (MS) will be connected to multiple BSs in its cell. In downlink each BS will transmit same data to the MS using certain power control scheme. Three power control schemes have been studied. One scheme distributes the power equally among all the BSs communicating to a certain MS, maintaining a constant transmit power. Second scheme maintains a constant power at the MS receiver taking into account the path loss. Third scheme analyzed is the famous water filling solution to compute the transmitted power in each BS-MS channel keeping the total power level constant. This scheme will have the advantage that transmitted power from each base station will be changed adaptively based on the channel SNR and interference conditions to provide maximum channel capacity. However it has been concluded from this work that this scheme is suitable for a MIMO system unlike this work which considers a MISO system. A conventional matched filter receiver is implemented at the MS. The communication channel has been modeled to have AWGN, frequency non-selective fast rayleigh multipath fading, considering the effect of path loss and MAI.

Download or read book Frequency Domain Multiuser Detection for CDMA Systems written by Paulo Silva and published by CRC Press. This book was released on 2022-09-01 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future broadband wireless communication systems are expected to be able to offer new and powerful services enabling fast transmission rates of several tens of Mbit/s. This is an ambitious challenge especially for mobile communication systems since these systems should be able to cope with severely time dispersive channels, associated to the signal multipath propagation. Moreover, these systems should have high spectral and power efficiencies, as well as high capacity and flexibility. Spread spectrum techniques, particularly coded division multiple access (CDMA) techniques allow high capacity and flexibility, continuous transmission requiring low-peak power requirements for the amplifiers, as well as some robustness against fading and time-dispersion effects associated with the multipath propagation. When employed in prefix assisted (PA) block transmission schemes combined with frequency-domain receiver implementations they become especially interesting for broadband wireless systems. In Frequency-Domain Multiuser Detection for CDMA Systems the use of PA block transmission is considered in the context of both DS (Direct Sequence) and MC (Multicarrier) CDMA schemes. The main goal is the study of frequency-domain multiuser detection techniques with iterative signal detection/decoding techniques, also in combination with estimation and cancelation of nonlinear distortion effects. The receiver structures are suitable to scenarios with high interference levels and strongly time-dispersive channels.

Download or read book Multi Carrier Spread Spectrum Related Topics written by Khaled Fazel and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-Carrier Spread-Spectrum has been deeply studied and new alternative solutions have been proposed. This book edits the newest contributions and research results in this new field presented at the Third International Workshop on MC-SS & Related Topics, held in Oberpfaffenhofen, Germany.

Download or read book Multicarrier Techniques for 4G Mobile Communications written by Shinsuke Hara and published by Artech House. This book was released on 2003 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the research for future fourth generation (4G)mobile communication systems has been launched worldwide in major companies and academic institutions, forward-thinking professionals are striving to gain a thorough understanding of the cutting-edge technologies and design techniques that will make these systems work. This unique new book helps you do just that. It provides you with a comprehensive introduction to multicarrier techniques for 4G mobile communications with a special focus on the analytical aspects. Radio channel characteristics and phenomena are explained along with discussions on the advantages and disadvantages of OFDM scheme. You get in-depth explanations of new multicarrier-related techniques, MC-CDMA, research on several 4G systems and a look at several problems to be overcome regarding these systems.