Download or read book Contributions on Receiver Design and Channel Estimation for Multi carrier DS CDMA Mobile Systems written by Ali Jamoos and published by . This book was released on 2007 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation deals with the development of receivers and channel estimation techniques for multi-carrier DS-CDMA mobile wireless systems. Two major problems should be taken into account in that case. Firstly, the Multiple Access Interference (MAI) caused by other users. Secondly, the multi-path fading of mobile wireless channels. In the first part of the dissertation, we propose two adaptive structures (called separate and joint detection) to design Minimum Mean Square Error (MMSE) receivers, based on the Affine Projection Algorithm (APA). These receivers are able to suppress the MAI, particularly when the fading channel is time-invariant. However, as they require a training sequence for every active user, we then propose two blind adaptive multiuser receiver structures based on a blind APA-like multiuser detector. In that case, only the knowledge of the spreading code of the desired user is required. When the spreading codes of all users are available, a decorrelating detector based receiver is proposed and is able to completely eliminate the MAI without any training. In the second part, as receiver design usually requires the estimation of the channel, we propose several training-based algorithms for the estimation of time-varying Rayleigh fading channels in multi-carrier systems. For this purpose, the fading channels are approximated by autoregressive (AR) processes whose order is higher than two. The first algorithm makes it possible to jointly estimate the channel and its AR parameters based on two-cross-coupled Kalman filters. Nevertheless, this filtering is based on restrictive Gaussian assumptions. To relax them, we investigate the relevance of a structure based on two-cross-coupled H_inf filters. This method consists in minimizing the influence of the disturbances such as the additive noise on the estimation error. Finally, we propose to view the channel estimation as an Errors-In-Variables (EIV) issue. In that case, the channel AR parameters and the variances of both the driving process and the measurement noise in the state-space representation of the system are estimated from the null space of suitable correlation matrices.

Download or read book Aspects of Channel Estimation and Receiver Design for DS CDMA Systems written by Shujun Chen and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Multi Carrier CDMA Mobile Radio Systems written by Stefan Kaiser and published by . This book was released on 1998 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory and Applications of OFDM and CDMA written by Henrik Schulze and published by John Wiley & Sons. This book was released on 2005-10-31 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory and Applications of OFDM and CDMA is an ideal foundation textbook for those seeking a sound knowledge of this fast-developing field of wideband communications. The advanced transmission techniques of OFDM, applied in wireless LANs and in digital and video broadcasting, and CDMA, the foundation of 3G mobile communications, have been part of almost every communication system that has been designed in recent years, with both offering a high degree of flexibility in adjusting the system to the requirements of the application and to the impairments caused by the transmission channel. Starting from the basics of digital transmission theory, the reader gains a comprehensive overview of the underlying ideas of these techniques and their strengths and weaknesses under various conditions. In this context, the specific requirements of the mobile radio channel and their relevance for the design of digital transmission systems are discussed and related to the items of channel coding and modulation. Clear explanation of the basics of digital communications, mobile radio channels, coding and modulation, OFDM as a multicarrier system and CDMA as an application of spread spectrum techniques Discusses the most important mobile radio and digital broadcasting systems that use OFDM and CDMA, and explains in detail the underlying ideas for the choice of system parameters Progresses from the fundamentals of wideband communication through to modern applications Includes a Companion Website featuring a solutions manual, electronic versions of the figures and other useful resources This volume will be an invaluable resource to advanced undergraduate students and first/second year postgraduates of electrical and engineering and telecommunications. It will also appeal to practising engineers, researchers and those in academia who wish to expand their knowledge on modern aspects of digital communications and systems in a mobile radio environment.

Download or read book The Effects of Channel Estimation Errors on Wideband CDMA Systems with Path Frequency Time and Space Diversity written by Lucy Lok-Kwan Chong and published by . This book was released on 2001 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Channel Estimation and Multiuser Detection Algorithms for Multicarrier mc Cdma Communications Systems written by Hui Cheng and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "New Channel Estimation and Multiuser Detection Algorithms for Multicarrier(MC)-CDMA Communications Systems" by Hui, Cheng, 成慧, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of the thesis entitled New Channel Estimation and Multiuser Detection Algorithms For Multicarrier (MC)-CDMA Communications Systems submitted by Cheng Hui for the degree of Doctor of Philosophy at the University of Hong Kong in September 2005 Multicarrier code division multiple access (MC-CDMA) has been recently proposed as an efficient multicarrier transmission scheme for supporting multiple access communications. However, MC-CDMA is an interference-limited system, which is rather sensitive to multiple access interference (MAI). Multiuser detection techniques are critical to mitigate MAI. Meanwhile, channel estimation is essential to the coherent detection of MC-CDMA signals. This thesis is dedicated to new channel estimation and multiuser detection algorithms for wireless MC-CDMA systems. New blind constrained minimum output energy (CMOE)-based and subspace-based multiuser detection and channel estimation algorithms are first developed. In particular, a new blind CMOE receiver is proposed. The proposed CMOE receiver is based on recursive least square (RLS) updating, and it minimizes the receiver''s output energy while preserving the components of the desired signal. iiiBy imposing quadratic weight constraint, the CMOE detector is made more robust against the channel and correlation matrix estimation errors, and a better performance over the standard CMOE detector is obtained. The steady-state signal-to-interference-plus-noise ratio (SINR) performance of the blind adaptive CMOE and training adaptive minimum mean squared-error (MMSE) detectors is also analyzed. A blind mode decision-directed MMSE detector is then proposed to further improve the performance of the blind CMOE receivers. Simulation results show that the blind mode decision-directed MMSE detector substantially improves the system performance when the frequency-selective channel is slowly varying. Blind and group-blind subspace-based MMSE multiuser detectors are also developed, where the channel coefficients can be blindly estimated. The proposed group-blind multiuser detector considerably outperforms the blind subspace-based method in uplink MC-CDMA channels. It exploits the spreading codes of a group of known users within the cell, while suppressing the unknown interferers from other cells using the MMSE principle. The adaptive implementation of the blind and group-blind multiuser detectors is also studied based on signal and noise subspace tracking algorithms. Numerical simulations show that the convergence of the projection approximation subspace tracking with deflation (PASTd) algorithm is quite slow, while the more complicated bi-iteration square-root singular value decomposition (Bi-SVD) signal subspace tracker presents performance close to the solution with exact singular value decomposition (SVD). MC-CDMA systems are sensitive to narrowband interference (NBI). A new robust channel estimator and a robust multiuser detector are developed to combat time-varying NBI. In particular, an efficient weighted recursive least M-estimate (WRLM) algorithm is proposed to recursively estimate the frequency-selective ivfading channel while providing improved robustness to the time-varying NBI. Furthermore, a weighted least M-estimate (WLM) detector is developed to jointly suppress MAI and time-varying NBI. Simulations show that the proposed robust channel estimator and multiuser d

Download or read book Pilot Assisted Channel Estimation for Multipath DS CDMA Systems written by Mansour Tahernezhadi and published by . This book was released on 2009-11 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiuser Detection and Channel Estimation for DS CDMA Systems written by Alexander Lampe and published by . This book was released on 2003 with total page 294 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 Frequency Domain Receiver Design for Doubly Selective Channels written by Paulo Montezuma and published by CRC Press. This book was released on 2017-06-26 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frequency-Domain Receiver Design for Doubly-Selective Channels discusses broadband wireless transmission techniques, which are serious candidates to be implemented in future broadband wireless and cellular systems, aiming at providing high and reliable data transmission and concomitantly high mobility. This book provides an overview of the channel impairments that may affect performance of single carrier and multi-carrier block transmission techniques in mobile environments. Moreover, it also provides a new insight into the new receiver designs able to cope with double selectivity that affects present and future broadband high speed mobile communication systems.

Download or read book Single and Multi Carrier DS CDMA written by Lajos L. Hanzo and published by Wiley-IEEE Press. This book was released on 2003-09-26 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is dedicated to a range of CDMA and MC-CDMA transmission aspects of systems designed for communicating over fading wireless channels. Currently, a technical in-depth book on this subject, which has a similar detailed exposure of the recent advances in CDMA, M-ary CDMA and MC-CDMA, is unavailable. 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 five main parts: Part I: provides a detailed introduction to the subject of CDMA systems designed for employment in various application Part II: deals with the currently hot topic of genetic algorithm assisted multiuser detection Part III: gives a detailed account of new, reduced-complexity M-ary CDMA schemes Part IV: considers a range of novel MC-CDMA schemes which have the potential of supporting numerous design objectives Part V: provides an overview of the 3G wireless system proposals and characterises the expected network capacity gains attained with the aid of adaptive CDMA systems By providing an all-encompassing self-contained treatment this groundbreaking volume will have appeal to researchers, postgraduate students, academics practising research and development engineers working for wireless communications and computer networking companies, as well as senior undergraduate students and technical managers in the field.

Download or read book Channel Estimation in Multicarrier Code Division Multiple Access written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The concepts of OFDM and MC-CDMA are not new but the new technologies to improve their functioning is an emerging area of research. In general, most mobile communication systems transmit bits of information in the radio space to the receiver. The radio channels in mobile radio systems are usually multipath fading channels, which cause inter-symbol interference (ISI) in the received signal. To remove ISI from the signal, there is a need of strong equalizer. In this thesis we have focused on simulating the OFDM and MC-CDMA systems in MATLAB and designed the channel estimation for them.

Download or read book Interative Receivers with Channel Estimation for Multi carrier Systems written by Abdul Rehman Usmani and published by . This book was released on 2006 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book OFDM Baseband Receiver Design for Wireless Communications written by Tzi-Dar Chiueh and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency-division multiplexing (OFDM) access schemes are becoming more prevalent among cellular and wireless broadband systems, accelerating the need for smaller, more energy efficient receiver solutions. Up to now the majority of OFDM texts have dealt with signal processing aspects. To address the current gap in OFDM integrated circuit (IC) instruction, Chiueh and Tsai have produced this timely text on baseband design. OFDM Baseband Receiver Design for Wireless Communications covers the gamut of OFDM technology, from theories and algorithms to architectures and circuits. Chiueh and Tsai give a concise yet comprehensive look at digital communications fundamentals before explaining modulation and signal processing algorithms in OFDM receivers. Moreover, the authors give detailed treatment of hardware issues -- from design methodology to physical IC implementation. Closes the gap between OFDM theory and implementation Enables the reader to transfer communication receiver concepts into hardware design wireless receivers with acceptable implementation loss achieve low-power designs Contains numerous figures to illustrate techniques Features concrete design examples of MC-CDMA systems and cognitive radio applications Presents theoretical discussions that focus on concepts rather than mathematical derivation Provides a much-needed single source of material from numerous papers Based on course materials for a class in digital communication IC design, this book is ideal for advanced undergraduate or post-graduate students from either VLSI design or signal processing backgrounds. New and experienced engineers in industry working on algorithms or hardware for wireless communications devices will also find this book to be a key reference.

Download or read book The Performance Analysis of Space Time Spreading CDMA on Transmit and Receive Antenna Diversity Systems with Imperfect Channel Estimation written by Norihito Aoki and published by . This book was released on 2002 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimation of Fading Channel in DS Cdma Multiuser Communications Systems written by Chun-Yu Fung and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Estimation of Fading Channel in DS-CDMA Multiuser Communications Systems" by Chun-yu, Fung, 馮震宇, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of the Thesis Entitled Estimation of Fading Channel in DS-CDMA Multiuser Communications Systems submitted by Fung Chun Yu for the degree of Master of Philosophy at the University of Hong Kong in December 2002 Multipath fading and multiuser access interference are two major impairments in direct-sequence code-division multiple-access (DS-CDMA) systems. Efficient channel estimation and multiuser detection techniques play important roles in overcoming these deficiencies. This thesis is concerned with the design of a space-time (ST) blind adaptive receiver for DS-CDMA systems and the accompanied channel estimation algorithm. A new space-time decorrelating RAKE (ST-DRAKE) receiver is developed for blind reception of CDMA signals in frequency-selective fading channels. It has the advantage that only the knowledge of the desired user's signature waveform is required and therefore no transmission of training sequence is needed. The ST-DRAKE receiver consists of two parts. The first part is a set of constrained adaptive filters that are designed to suppress interference based on the minimum output energy criterion. These filters are implemented in a structure analogous to the general sidelobe canceller in array processing, which is implemented by a multistage Weiner filter is employed to reduce the complexity of the receiver. The second part of the ST-DRAKE receiver coherently combines the outputs of the constrained adaptive filters and gives an estimate of the transmitted signal. Simulation results show that the ST- DRAKE delivers significant performance improvement by exploiting the spatial diversity of the antenna array. The problem of estimating fast fading channels in the proposed receiver is also addressed. The time-varying channel is modeled as an autoregressive process and the Kalman filter is employed to estimate the time-varying channel coefficients. A robust Kalman filter based on the M-estimate cost function is also developed to suppress impulsive noise present in the received signals. Simulation results show that the Kalman filter provides more accurate channel estimate to the ST-DRAKE than using the decomposition method. Simulation results also show that the coupled receiver has a performance comparable to the optimum minimum mean-squared error receiver with known channel information. DOI: 10.5353/th_b2750902 Subjects: Code division multiple access Wireless communication systems