Download or read book Practical Design and Performance Evaluation of Dynamic Channel Estimation Based Log MAP Turbo Decoder for DS CDMA Systems in Multi Path Fading Environment written by Fan Mo and published by . This book was released on 2002 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improved Decoder Metrics for DS CDMA in Practical 3G Systems written by Shady Osama Mahmoud Elbassiouny and published by . This book was released on 2016 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: While 4G mobile networks have been deployed since 2008. In several of the more developed markets, 3G mobile networks are still growing with 3G having the largest market -in terms of number of users- by 2019. 3G networks are based on Direct- Sequence Code-Division Multiple-Access (DS-CDMA). DS-CDMA suffers mainly from the Multiple Access Interference (MAI) and fading. Multi-User Detectors (MUDs) and Error Correcting Codes (ECCs) are the primary means to combat MAI and fading. MUDs, however, suffer from high complexity, including most of sub-optimal algorithms. Hence, most commercial implementations still use conventional single-user matched filter detectors. This thesis proposes improved channel decoder metrics for enhancing uplink performance in 3G systems. The basic idea is to model the MAI as conditionally Gaussian, instead of Gaussian, conditioned on the users’ cross-correlations and/or the channel fading coefficients. The conditioning implies a time-dependent variance that provides enhanced reliability estimates at the decoder inputs. We derive improved log-likelihood ratios (ILLRs) for bit- and chip- asynchronous multipath fading channels. We show that while utilizing knowledge of all users’ code sequences for the ILLR metric is very complicated in chip-asynchronous reception, a simplified expression relying on truncated group delay results in negligible performance loss. We also derive an expression for the error probability using the standard Gaussian approximation for asynchronous channels for the widely used raised cosine pule shaping. Our study framework considers practical 3G systems, with finite interleaving, correlated multipath fading channel models, practical pulse shaping, and system parameters obtained from CDMA2000 standard. Our results show that for the fully practical cellular uplink channel, the performance advantage due to ILLRs is significant and approaches 3 dB..

Download or read book Iterative EM Channel Estimation for Turbo coded DS CDMA Receiver Under Different Communication Scenarios written by and published by . This book was released on 2008 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis proposes a scheme of obtaining an estimate of channel coefficients and noise power spectral density (PSD) using iterative expectation maximization based on a turbo-coded code-division multiple-access (CDMA) receiver under different communication scenarios such as time-varying interference and pulse-band jamming. At the receiver, an initial estimate is obtained with the aid of pilot symbols. The subsequent values of channel coefficient and noise PSD are updated by soft feedback from the turbo decoder. The updated channel coefficient and noise PSD are iteratively passed to the turbo decoder, which results in improved decoding accuracy. The proposed systems are verified through simulations using a structure similar to the Third Generation Partnership Project Long-Term Evolution (3GPP LTE) system under Jakes and Rayleigh fading environments. In addition, this thesis also proposes the scheme of obtaining an estimate of channel coefficients and noise PSD without sending any pilots under a single-user environment. At the receiver, the initial estimate of channel coefficient and noise PSD are obtained without pilots using blind estimation, and then the further estimations are done using expectation maximization. The estimated values are updated iteratively by feedback from the turbo decoder. The updated channel coefficient and noise PSD are iteratively passed to the turbo decoder, which yields improved decoding results. The elimination of pilot symbols sacrifices performance but allows increased energy per transmitted symbol, increased information throughput, or the inclusion of additional parity bits.

Download or read book Training Based Channel Estimation Approaches for Multipath Fading CDMA Systems written by Ahmet Rizaner and published by . This book was released on 2004 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Multi user Detection and Blind Channel Estimation for DS CDMA Systems written by Sergeï Burykh and published by . This book was released on 2003 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbo Coding Turbo Equalisation and Space Time Coding written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2011-05-03 with total page 839 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the full range of channel codes from the most conventional through to the most advanced, the second edition of Turbo Coding, Turbo Equalisation and Space-Time Coding is a self-contained reference on channel coding for wireless channels. The book commences with a historical perspective on the topic, which leads to two basic component codes, convolutional and block codes. It then moves on to turbo codes which exploit iterative decoding by using algorithms, such as the Maximum-A-Posteriori (MAP), Log-MAP and Soft Output Viterbi Algorithm (SOVA), comparing their performance. It also compares Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM) and Iterative BICM (BICM-ID) under various channel conditions. The horizon of the content is then extended to incorporate topics which have found their way into diverse standard systems. These include space-time block and trellis codes, as well as other Multiple-Input Multiple-Output (MIMO) schemes and near-instantaneously Adaptive Quadrature Amplitude Modulation (AQAM). The book also elaborates on turbo equalisation by providing a detailed portrayal of recent advances in partial response modulation schemes using diverse channel codes. A radically new aspect for this second edition is the discussion of multi-level coding and sphere-packing schemes, Extrinsic Information Transfer (EXIT) charts, as well as an introduction to the family of Generalized Low Density Parity Check codes. This new edition includes recent advances in near-capacity turbo-transceivers as well as new sections on multi-level coding schemes and of Generalized Low Density Parity Check codes Comparatively studies diverse channel coded and turbo detected systems to give all-inclusive information for researchers, engineers and students Details EXIT-chart based irregular transceiver designs Uses rich performance comparisons as well as diverse near-capacity design examples

Download or read book Multiuser Detection and Channel Estimation for DS CDMA Systems written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 K. Fazel and published by John Wiley & Sons. This book was released on 2004-02-06 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frequency spectrum is a limited and valuable resource for wireless communications. A good example can be observed among network operators in Europe for the prices to pay for UMTS-frequency bands. Therefore, the first goal when designing future wireless communication systems (e.g. 4G - fourth generation) has to be the increase in spectral efficiency. The development in digital communications in the past years has enabled efficient modulation and coding techniques for robust and spectral efficient data, speech, audio and video transmission. These are the multi-carrier modulation (e.g. OFDM) and the spread spectrum technique (e.g. DS-CDMA), where OFDM was chosen for broadcast applications (DVB, DAB) as well as for broadband wireless indoor standards (ETSI HIPERLAN-II, IEEE-802.11) and the DS-CDMA was selected in mobile communications (IS-95, third generation mobile radio systems world wide, UMTS/IMT 2000). Since 1993 various combinations of multi-carrier (MC) modulation and the spread spectrum (SS) technique have been introduced and the field of MC-SS communications has become an independent and important research topic with increasing activities. New application fields have been proposed such as high rate cellular mobile, high rate wireless indoor and LMDS. It has been shown that MC-SS offers the high spectral efficiency, robustness and flexibility that is required for the next generation systems. Meanwhile, different alternative hybrid schemes such as OFDM/OFDMA, MC-TDMA, etc. have been deeply analysed and adopted in different international standards (ETSI-BRAN, IEEE-802 & MMAC). Multi-Carrier & Spread-Spectrum: Analysis of Hybrid Air Interfaces draws together all of the above mentioned hybrid schemes therefore providing a greatly needed resource for system engineers, telecommunication designers and researchers in order to enable them to develop, build and deploy several schemes based on MC-transmission for the next generation systems (which will be an integration of broadband multimedia services covering both 4G mobile and fixed wireless systems). * Offers a complete treatment of multi-carrier, spread-spectrum (SS) and time division multiplexing (TDM) techniques * Provides an in-depth insight into hybrid multiple access techniques based on multi-carrier (MC) transmission * Presents numerous hybrid multiple access and air interface architectures including OFDM/CDMA, MC-CDMA, MC-DS-CDMA and MT-CDMA * Covers new techniques such as space-time coding and software radio Telecommunications engineers, hardware & software system designers and researchers as well as students, lecturers and technicians will all find this an invaluable addition to their bookshelf.

Download or read book Performance and Analysis of Digital Code Tracking Loops for DS CDMA Systems Over Fading Channels written by 蔡宗樺 and published by . This book was released on 2006 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On Multipath Channel Estimation for CDMA Systems written by Iain G. Stirling and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blind Data Detection and Channel Estimation for CDMA Systems Over Fading Channels written by Qian Yu and published by . This book was released on 2005 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Wireless Communication written by David Tse and published by Cambridge University Press. This book was released on 2005-05-26 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook takes a unified view of the fundamentals of wireless communication and explains cutting-edge concepts in a simple and intuitive way. An abundant supply of exercises make it ideal for graduate courses in electrical and computer engineering and it will also be of great interest to practising engineers.