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Book Performance Analysis for a New Model of the Fast Frequency Hopped Code Division Multiple Access Spread Spectrum Communication System

Download or read book Performance Analysis for a New Model of the Fast Frequency Hopped Code Division Multiple Access Spread Spectrum Communication System written by Ming-li Shen and published by . This book was released on 1993 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book PERFORMANCE ANALYSIS OF FREQUENCY HOPPED SPREAD SPECTRUM COMMUNICATION SYSTEMS WITH WORST CASE JAMMING INTERFERENCE

Download or read book PERFORMANCE ANALYSIS OF FREQUENCY HOPPED SPREAD SPECTRUM COMMUNICATION SYSTEMS WITH WORST CASE JAMMING INTERFERENCE written by SANG KYU PARK and published by . This book was released on 1987 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: strategies we consider allow the jammer to pulse between several power values subject to an average power constraint.

Book Performance Analyses of Frequency hopped Spread spectrum Multiple Access Systems in Fading Environments

Download or read book Performance Analyses of Frequency hopped Spread spectrum Multiple Access Systems in Fading Environments written by Usa Svasti-Xuto and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this dissertation is the performance analyses of two classes of frequency-hopped spread-spectrum multiple access (FH-SSMA) systems in various fading environments. The capacity of Viterbi's FH-SSMA system is evaluated under three types of fading, namely Rician, shadowed Rician, and Nakagami fading. The results of recent experiments have indicated that these fading phenomena occur in various environments where the FH-SSMA system may be implemented. In this dissertation, the deletion probability for each fading scenario is derived. Subsequently, the system capacity is analyzed in terms of maximum number of users versus average bit error rate. The effect of a change in the signal-to-noise ratio level on the system capacity is also demonstrated. For Rician fading, it is found that the capacity of the system with a Rician factor of 2 dBis reduced by 13 percent as compared to the capacity of the non-fading case. For shadowed Rician fading, three shadowing scenarios are considered: light, average, and heavy. It is shown that the light and the average shadowing scenarios provide only a slight decrease in the capacity, while the heavy shadowing scenario renders a capacity identical to that for the Rayleigh fading case. Finally, for Nakagami fading the capacity is found to decrease by 50 percent as the fading parameter is reduced to 0.5. The performance of a cellular frequency-hopped spread-spectrum multiple access system is studied under an indoor environment. It is demonstrated how the system capacity, given in terms of the number of users per cell, is affected by the number of cells in the system. Also, the influence of the delay spread, which is the result of multipath propagation, is investigated. The analysis focuses on a worst-case scenario where a user receives both the desired and interfering signals with equal power levels. This scenario applies to both the downlink and the uplink. It is shown that the system capacity is reduced drastically as the number of adjacent interfering cells increases from one to three. Previous work concerning the indoor multipath propagation assumed that the number of paths is fixed, the path delays are uniformly distributed, and the path gains are equal. In this dissertation, a more realistic channel model derived from actual impulse response measurements by Saleh and Valenzuela is employed. The model consists of clusters of rays with constant cluster and ray arrival rates and power-delay time constants. The system performance is shown to be affected strongly by the change in the power-delaytime constants, yet only slightly influenced by the variation in the arrival rates of the rays and clusters. In addition, the degradation in the system performance due to the delay spread becomes more severe as the transmission rate increases.

Book Performance Analysis of Noncoherent Slow Frequency hopped Spread spectrum Communications Over Specular Multipath Fading Channels

Download or read book Performance Analysis of Noncoherent Slow Frequency hopped Spread spectrum Communications Over Specular Multipath Fading Channels written by Kuo Tung Chiang and published by . This book was released on 1986 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Performance of Fast Frequency hopping Diversity Combiners in Multiple Access Interference for Ad Hoc Networks

Download or read book Performance of Fast Frequency hopping Diversity Combiners in Multiple Access Interference for Ad Hoc Networks written by Helene Ejenyi Tayong and published by . This book was released on 2006 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this work is to evaluate the performance of fast frequency-hopping diversity combiners in multiple access interference for ad hoc networks. Multiple access interference (MAI) is the interference that is common in a network with many devices sharing the channel. A model developed in, i.e. the alpha-stable distribution suggested for modeling impulsive signals, is investigated to characterize MAI for an ad hoc network. Impulsive processes are characterized by the presence of spikes or extreme outliers. As such, their probability density functions (pdfs) have heavier tails. Such impulsive behaviors have been verified experimentally in various radio and underwater acoustic channels. The characteristic exponent (the parameter alpha) controls the impulsive behavior of the process. Techniques based on characteristic functions, the Fourier transform of the probability density function (pdf), are used to calculate the probability of error since no-closed form exists for their distributions. Frequency-hopping spread spectrum (FHSS) multiple access radio networks using the same modulation and power is considered. FHSS is a powerful technique used in communication systems to provide protection against jamming and fading. The problem is applicable in wireless random-access communication systems where information about transmitters' positions is not provided. The signal strength attenuates with distance. The focus is on Fast Frequency-hopping (FFH) in order to exploit frequency diversity; a condition where the same data bit is transmitted on multiple independently faded hops. A modulation technique called frequency hopping multilevel frequency shift keying (FH-MFSK) is used to allow many users to effectively share the same frequency band. The Reduced Fuzzy Rank Order Detector (R-FROD), a FFH diversity combiner is studied in this interference environment and its performance is compared with that of hard decision majority vote (HDMV) detector, maximum rank sum receiver (MRSR) and order statistic normalized envelope detector (OS-NED). Simulation results show that the R-FROD is able to outperform the MRSR, OS-NED and HDMV detectors across a range of values for alpha. R-FROD is analyzed in alpha-stable environment using Gaussian and Cauchy membership functions. Simulation results show that either membership function can be used in R-FROD to analyze its performance in an alpha-stable environment. Increasing the hop sequence length reduces the probability of error. The analysis presented is important in the design of efficient interference suppression techniques and in solving mobile wireless communication systems. -- Abstract.

Book Multicarrier Communications

Download or read book Multicarrier Communications written by Lie-Liang Yang and published by John Wiley & Sons. This book was released on 2009-01-21 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Benefiting from both time-domain and frequency-domain signal processing techniques, multicarrier systems have the potential for achieving high spectral-efficiency, high-flexibility and low-complexity wireless communications. Multicarrier techniques therefore constitute the promising techniques for implementation of future generations of wideband, broadband and ultra-wideband systems. Multicarrier Communications offers comprehensive and in-depth evaluation of numerous topics in the area, covering the fundamental principles of spread-spectrum and multicarrier CDMA as well as more advanced topics such as multiuser detection (MUD), multiuser transmitter preprocessing (MUTP), MIMO and space-time processing. It examines OFDM and various multicarrier CDMA within an unified framework and provides analytical approaches and formulas for error-performance evaluation of numerous multicarrier systems. Examines MUD and MUTP in parallel to illustrate the strong duality between receiver optimization and transmitter optimization Comprehensively establishes the theory of noncoherent MUD and noncoherent interference suppression Details the body of knowledge on MIMO theory and space-time multicarrier communications Contains tables, diagrams and figures to illustrate the performance results. Practicing electrical engineers and researchers in wireless communications will find Multicarrier Communications an invaluable guide. It will also be of interest to senior undergraduate and graduate students on wireless communications courses.

Book Analysis of Binary Frequency hopped Spread spectrum Multiple access Communications Systems

Download or read book Analysis of Binary Frequency hopped Spread spectrum Multiple access Communications Systems written by Evaggelos A. Geraniotis and published by . This book was released on 1980 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Performance Study of Hybrid Spread Spectrum Techniques

Download or read book Performance Study of Hybrid Spread Spectrum Techniques written by and published by . This book was released on 2005 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the performance analysis of hybrid direct sequence/slow frequency hopping (DS/SFH) and hybrid direct sequence/fast frequency hopping (DS/FFH) systems under multi-user interference and Rayleigh fading. First, we analyze the performance of direct sequence spread spectrum (DSSS), slow frequency hopping (SFH) and fast frequency hopping (FFH) systems for varying processing gains under interference environment assuming equal bandwidth constraint with Binary Phase Shift Keying (BPSK) modulation and synchronous system. After thorough literature survey, we show that hybrid DS/FFH systems outperform both SFH and hybrid DS/SFH systems under Rayleigh fading and multi-user interference. Also, both hybrid DS/SFH and hybrid DS/FFH show performance improvement with increasing spreading factor and decreasing number of hopping frequencies.

Book Performance of Cellular Frequency Hopped Spread Spectrum Radio Networks

Download or read book Performance of Cellular Frequency Hopped Spread Spectrum Radio Networks written by Jeffrey W. Gluck and published by . This book was released on 1989 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple access interference is characterized for cellular mobile networks, in which users are assumed to be Poisson-distributed in the plane and employ frequency-hopped spread-spectrum signaling with transmitter-oriented assignment of frequency-hopping patterns. Exact expressions for the bit error probabilities are derived for binary coherently demodulated systems without coding. Approximations for the packet error probability are derived for coherent and noncoherent systems and these approximations are applied when forward-error-control coding is employed. In all cases, the effects of varying interference power are accurately taken into account according to some propagation law. Numerical results are given in terms of bit error probability for the exact case and throughput for the approximate analyses. Comparisons are made with previously derived bounds and it is shown that these tend to be very pessimistic. Keywords: Communications network; Multiple access; Frequency hopping; Spread spectrum; Error control coding. (jhd).

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Performance Evaluation of Frequency Hopped Spread Spectrum Multi Hop Networks

Download or read book Performance Evaluation of Frequency Hopped Spread Spectrum Multi Hop Networks written by J. W. Gluck and published by . This book was released on 1988 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Primary and secondary multiple-access interference processes are characterized for multi-hop packet radio networks, in which users are assumed to be Poisson-distributed in the plane and to use frequency hopped spread-spectrum signaling with a receiver-oriented assignment of frequency-hopping patterns. The throughput per node and the average forward progress are then evaluated for frequency-hopped multi-hop networks that employ (i) random forward routing with fixed transmission radius (RFR) and(ii) most forward progress routing with fixed transmission radius (MFR). The optimal average number of neighbors and transmission radius are derived for these cases when Reed-Solomon forward-error-control coding with minimum distance decoding or binary convolutional coding with Viterbi decoding is employed.