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Author: Vidhyacharan Bhaskar Publisher: LAP Lambert Academic Publishing ISBN: 9783843374521 Category : Languages : en Pages : 160
Book Description
This dissertation incorporates rate adaptation schemes for direct sequence spread spectrum systems. Subspace and pilot-aided methods for channel estimation can be used to estimate the nature of time varying channels. The simulated performance of punctured and repetition codes agrees well with the upper and lower theoretical bounds in hard-decision decoding over Rayleigh and Rician fading channels. The expression for the upper bound on soft-decision decoding is also derived and plotted. An adaptive forward error correction (FEC) coding scheme is proposed to combat the detrimental effects of fading in a mobile multiuser environment. The throughput of the proposed adaptive FEC scheme reaches the highest code rate of the punctured convolutional code used. The throughput of the proposed hybrid automatic repeat request (H-ARQ) scheme exceeds that of the generalized H-ARQ scheme for high signal to noise ratios.
Author: Vidhyacharan Bhaskar Publisher: LAP Lambert Academic Publishing ISBN: 9783843374521 Category : Languages : en Pages : 160
Book Description
This dissertation incorporates rate adaptation schemes for direct sequence spread spectrum systems. Subspace and pilot-aided methods for channel estimation can be used to estimate the nature of time varying channels. The simulated performance of punctured and repetition codes agrees well with the upper and lower theoretical bounds in hard-decision decoding over Rayleigh and Rician fading channels. The expression for the upper bound on soft-decision decoding is also derived and plotted. An adaptive forward error correction (FEC) coding scheme is proposed to combat the detrimental effects of fading in a mobile multiuser environment. The throughput of the proposed adaptive FEC scheme reaches the highest code rate of the punctured convolutional code used. The throughput of the proposed hybrid automatic repeat request (H-ARQ) scheme exceeds that of the generalized H-ARQ scheme for high signal to noise ratios.
Author: Savo G. Glisic Publisher: John Wiley & Sons ISBN: 0470859253 Category : Technology & Engineering Languages : en Pages : 628
Book Description
CDMA (Code Division Multiple Access) is one type of multiple access system used in radio communication. Other multiple access methods include TDMA, FDMA, etc. WCDMA (Wideband Code Division Multiple Access) is the main air interface used for third generation mobile communication systems - UMTS (Universal Mobile Telecommunication System) and is characterised by a wider band than CDMA. WCDMA uses a wider radio band than CDMA, which was used for 2G systems, and has a high transfer rate and increased system capacity and communication quality by statistical multiplexing, etc. WCDMA efficiently utilises the radio spectrum to provide a maximum data rate of 2 Mbit/s. Third generation mobile communication systems are scheduled for operational startup in Japan and Europe in 2001-2002. Applying high-speed data transfer and state-of-the-art radio terminal technology, third generations systems enable multimedia and are currently in the process of being standardised under 3GPP. Among the three types of system to be standardised (i.e. WCDMA, MC-CDMA, UTRA TDD), Japan and Europe will adopt WCDMA in a strategy to take the lead through superior service. This volume will cover the latest theoretical principles of WCDMA and explain why these principles are used in the standards. Starting with a general overview, the more advanced material is then gradually introduced providing an excellent roadmap for the reader. * Presents comprehensive coverage of the theoretical and practical aspects of WCDMA * Provides a detailed roadmap by presenting the material step-by-step for readers from differing backgrounds * Systematically presents the latest results in the field Ideal for Engineers, academics and postgraduate students involved in research and development, engineers involved in management and administration.
Author: Mohamed Aljerjawi Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The application of space-time coding in wireless communication systems has shown to improve the quality of the received signal at the mobile user by placing the spatial diversity at the base station. In this thesis, we propose a simple space-time spreading scheme for code-division multiple-access (CDMA) systems over fast-fading channels. The proposed transmit diversity scheme is based on two transmit and M receive antennas and is suitable for Rayleigh fast-fading channels. In this we employ orthogonal spreading codes to exploit the time diversity introduced by the channel, and hence a two-fold of the diversity order obtained using existing spacetime spreading schemes is achieved. Nevertheless, for slowly-fading channels, we show that the proposed coding scheme reduces to existing schemes introduced in the literature with no performance degradation. Then, we examine the effect of using nonorthogonal spreading codes on the receiver performance. Our results show that using a simple adaptive decoder, based on the minimum mean-squared error (MMSE) criterion, the diversity order is still maintained and only a small loss in the signal-to noise ratio (SNR) is incurred relative to the ideal case with orthogonal codes.
Author: Lajos Hanzo Publisher: John Wiley & Sons ISBN: 0470861800 Category : Technology & Engineering Languages : en Pages : 1014
Book Description
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.
Author: Francis Swarts Publisher: Springer Science & Business Media ISBN: 146155103X Category : Technology & Engineering Languages : en Pages : 324
Book Description
CDMA Techniques for Third Generation Mobile Systems presents advanced techniques for analyzing and developing third generation mobile telecommunication systems. Coverage includes analysis of CDMA-based systems, multi-user receivers, Turbo coding for mobile radio applications, spatial and temporal processing techniques as well as software radio techniques. Special emphasis has been given to recent advances in coding techniques, smart antenna systems, spatial filtering, and software implementation issues. Internationally recognized specialists contributed to this volume, and each chapter has been reviewed and edited for uniformity. CDMA Techniques for Third Generation Mobile Systems is an invaluable reference work for engineers and researchers involved in the development of specific CDMA systems.
Author: Volker Kuhn Publisher: John Wiley & Sons ISBN: 0470034610 Category : Technology & Engineering Languages : en Pages : 388
Book Description
Wireless Communications over MIMO Channels: Applications to CDMA and Multiple Antenna Systems covers both, state-of-the-art channel coding concepts and CDMA and multiple antenna systems, rarely found in other books on the subject. Furthermore, an information theoretical analysis of CDMA and SDMA systems illuminate ultimate limits and demonstrates the high potential of these concepts. Besides spatial multiplexing, the use of multiple transmit antennas in order to increase the link reliability by diversity concepts (space-time coding) is described. Another focus is the application of error control coding in mobile radio communications Accompanying appendices include: basic derivations, tables of frequently used channel models, chain rules for entropy and information, data processing theorem, basics of linear algebra, Householder reflection and Givens rotation, and the LLL algorithm for lattice reduction.
Author: Vidhyacharan Bhaskar
Author: Vidhyacharan Bhaskar
Author: Vidhyacharan Bhaskar
Author: Savo G. Glisic
Author: Kai Tang
Author: Mohamed Aljerjawi
Author: Lajos Hanzo
Author: David Winston Hansquine
Author: Francis Swarts
Author: Volker Kuhn
Author: Zulfiquar Sayeed