Download or read book Performance Analysis of Decorrelating Detectors for Dual rate Synchronous DS CDMA Systems Over Frequency selective Rayleigh Fading Channels written by Xiangtao Li and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the performance of a decorrelating-based multiuser detector for frequency-selective channels is discussed. The users transmit data at two different rates are instead of one single rate. According to their transmission rates, the users are classified into two groups, a group of high rate users and a group of low rate users. It is assumed that over the time interval [0, T o], the low rate users transmit one bit, while the high rate users transmit M bits of information. At the receiving end, two types of decorrelators are examined to decode the signals: a low rate decorrelator (LRD) and a high rate decorrelator (HRD). The LRD makes a decoding decision for every T o seconds and views one high rate user as M effective low rate users. The HRD makes a decision for every T 1 = T o / M seconds and detects a bit from a low rate user M times during the time interval[0, T o]. The signals from the two groups are transmitted over frequency-selective multipath Rayleigh fading channels. The maximal ratio combining (MRC) technique is used in two parts of the receivers. First, the multipath diversity and MRC diversity reception method are utilized in the receivers to combat against the multipath fading. Secondly, in HRD, MRC is employed to implement a soft decoding rule for the low rate users. The error probability and asymptotic multiuser efficiency for both types of decorrelators will be evaluated and the simulation results given. It can be seen in the simulation results that the LRD is superior to the HRD in the performance for both low rate and high rate users.

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings written by and published by . This book was released on 2000 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IEEE International Conference on Personal Wireless Communications written by and published by . This book was released on 1997 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Science Technology Index written by and published by . This book was released on 1997 with total page 2948 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 1996 Fifth IEEE International Conference on Universal Personal Communications Record written by and published by . This book was released on 1996 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings Exhibition future Access written by and published by . This book was released on 1997 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Conference Record written by and published by . This book was released on 1994 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Communications Theory Mini Conference Record written by and published by . This book was released on 1994 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IEEE Emerging Technologies Symposium written by and published by . This book was released on 2000 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wireless Applications of Spread Spectrum Systems written by Sawasd Tantaratana and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 1998 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt: These selected readings bring together introductory and advanced papers on various wireless applications of spread spectrum technology. The papers are grouped into sections according to the application areas: spread-spectrum technology, cellular mobile systems, satellite communications, wireless local area networks, and the global positioning system (GPS).

Download or read book 2002 International Zurich Seminar on Broadband Communications written by and published by Institute of Electrical & Electronics Engineers(IEEE). This book was released on 2001 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: These conference notes on communication networks and systems cover topics including: wireless local area networks; power line communications; smart antennas and space time signal processing; xDSL; cable modem technologies; and signal propogation and channel modelling.

Download or read book An Application of the Chase Algorithm to Multiuser Detection written by Feng Liu and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With various added services in future wireless communication systems, the demand for fast and highly reliable data transmissions is continuously increasing. Multiple access interference (MAI) in direct-sequence code division multiple access (DS-CDMA) and constrained capacity in single-input single-output (SISO) are the major obstacles to achieve this purpose. For overcoming these limitations, the use of multiuser detection (MUD) and multiple-input multiple-output (MIMO) is necessary. In the area of error control coding, the Chase algorithm, which takes advantage of the different reliabilities of the received symbols and focuses on correcting the error in the weakest symbols, can achieve a near maximum-likelihood (ML) performance and with significant complexity reduction. In this thesis, we discuss the application of the Chase algorithm in multiuser detectors for the SISO-CDMA and MIMO-CDMA systems. In the SISO-CDMA systems, we develop a parallel interference cancellation (PIC) scheme using the Chase algorithm after the matched filters (MFs). This scheme is called Chase-PIC. Instead of optimizing the weight of each user as most of PIC detectors do, this detector provides a new optimizing approach right after the MFs. Based on the analysis of the complexity and performance over the flat and frequency-selective Rayleigh fading channels, we also propose a new Chase based multistage PIC that uses the normalized least-mean-square (NLMS) algorithm at the earlier stages and the Chase algorithm at the later stages. This proposed scheme can achieve a better performance than NLMS-PIC but with less complexity. In the MIMO-CDMA systems, we proposed a new Chase based multiuser detector over the flat Rayleigh fading channels. This detector focuses on correcting the error of the weakest detected symbol in the layered space-time multiuser detector (LAST-MUD). Compared to another Chase based detector, B-Chase, the proposed scheme has less complexity but with the tendency of achieving better performance at high signal-to-noise ratio (SNR).

Download or read book Adaptive Distributed Detection with Applications to Cellular CDMA written by Jian-Guo Chen and published by . This book was released on 1997 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chair and Varshney have derived an optimal rule for fusing decisions based on the Bayesian criterion. To implement the rule, probabilities of detection PD and false alarm PF for each detector must be known, which is not readily available in practice. This dissertation presents an adaptive fusion model which estimates the PD and PF adaptively by a simple counting process. Since reference signals are not given, the decision of a local detector is arbitrated by the fused decision of all the other local detectors. Adaptive algorithms for both equal probable and unequal probable sources, for independent and correlated observations are developed and analyzed, respectively. The convergence and error analysis of the system are analytically proven and demonstrated by simulations. In addition, in this dissertation, the performance of four practical fusion rules in both independent and correlated Gaussian noise is analyzed, and compared in terms of their Receiver Operating Characteristics (ROCs). Various factors that affect the fusion performance are considered in the analysis. By varying the local decision thresholds, the Rocs under the influence of the number of sensors, signal-to-noise ratio (SNR), the deviation of local decision probabilities, and correlation coefficient, are computed and plotted, respectively. Several interesting and key observations on the performance of fusion rules are drawn from the analysis. As an application of the above theory, a decentralized or distributed scheme in which each fusion center is connected with three widely spaced base stations is proposed for digital cellular code-division multi-access communications. Detected results at each base station are transmitted to the fusion center where the final decision is made by optimal fusion. The theoretical analysis shows that this novel structure can achieve an error probability at the fusion center which is always less than or equal to the minimum of the three respective base station. The performance comparison for binary coherent signaling in Rayleigh fading and log-normal shadowing demonstrates that the decentralized detection has a significant increased system capacity over conventional macro selection diversity. This dissertation analyzes the performance of the adaptive fusion method for macroscopic diversity combination in the wireless cellular environment when the error probability information from each base station detection is not available. The performance analysis includes the derivation of the minimum achievable error probability. An alternative realization with lower complexity of the optimal fusion scheme by using selection diversity is also proposed. The selection of the information bit in this realization is obtained either from the most reliable base station or through the majority rule from the participating base stations.

Download or read book Selective Multistage Detection Algorithm in Flat Rayleigh Fading Channel written by Li Pan and published by . This book was released on 2004 with total page 200 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.

Download or read book Adaptive Wireless Transceivers written by Lajos Hanzo and published by Wiley-IEEE Press. This book was released on 2002-04-03 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Wireless Transceivers provides the reader with a broad overview of near-instantaneously adaptive transceivers in the context of TDMA, CDMA and OFDM systems. The adaptive transceivers examined employ powerful turbo codecs, turbo equalisers and space-time codecs, equipping the reader with a future-proof technological road map. It demonstrates that adaptive transceivers are capable of mitigating the channel quality fluctuations of the wireless channel as a lower-complexity alternative to space-time coding. By contrast, if the higher complexity of multiple transmitters and multiple receiver-assisted systems is deemed acceptable, the advantages of adaptability erode. Provides an in-depth introduction to channel equalisers and Kalman filtering and discusses the associated complexity versus performance trade-offs Introduces wideband near-instantaneously adaptive transceivers and studies their performance both with and without turbo channel coding Describes how to optimise adaptive modulation mode switching and highlights a range of practical considerations Introduces neural network based channel equalisers and discusses Radial Basis Function (RBF) assisted equalisers embedded into adaptive modems supported by turbo channel coding and turbo channel equalisation Employs the above adaptive principles also in the context of CDMA and OFDM transceivers and discusses the pros and cons of space-time coding versus adaptive modulation Researchers, advanced students and practising development engineers working in wireless communications will all find this valuable text an informative read.