Download or read book Spread Spectrum Frequency hopping Systems with Majority Voting Fractional band Noise Interference Performance Analyses written by Vernon A. Dorrell and published by . This book was released on 1980 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spread Spectrum Systems written by Robert Clyde Dixon and published by Wiley-Interscience. This book was released on 1984 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diversity Combining for Frequency hop Spread spectrum Communications with Partial band Interference and Fading written by Catherine Marie Keller and published by . This book was released on 1985 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents results on the evaluation of several diversity combining techniques that are suggested for frequency-hop (FH) communications with partial-band interference and fading. The analysis covers systems with M-ary orthogonal signaling and noncoherent demodulation. The partial-band interference is modeled as a Gaussian process, although some of the results also apply to general (non-Gaussian) partial-band interference. The performance measures we use to evaluate the diversity combining techniques are the narrowband interference rejection capability and the signal to noise ratio requirement over the entire range of interference duty factors. We evaluate the exact probability of error for each of the diversity combining techniques studied. The performance of the optimum combining technique for receivers with perfect side information is established. It is shown that for receivers with perfect side information, the system performance does not change significantly with the choice of the diversity combining technique. However, the same schemes that work well in receivers with perfect side information perform poorly in receivers without side information. Keywords include: Diversity combining; Frequency-hop; Spread-spectrum; Partial band interference and Fading.
Download or read book PERFORMANCE ANALYSIS OF CODED FREQUENCY HOPPED SPREAD SPECTRUM SYSTEMS WITH UNKNOWN INTERFERENCE written by MANJUNATH V. HEGDE and published by . This book was released on 1987 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: combining and linear combining, are unable to overcome the worst case partial band noise, but clipped linear combining is asymptotically able to neutralize the partial band noise, i.e. allow its effect to be no worse than added white Gaussian noise of equivalent noise spectral density.
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.
Download or read book Performance Analysis of Diversity Combining for Frequency hop Communications Under Partial band and Multitone Interference written by Gang Li and published by . This book was released on 1992 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Spread Spectrum Communications Handbook Electronic Edition written by Marvin K. Simon and published by McGraw Hill Professional. This book was released on 2001-09-22 with total page 1250 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acknowledged Spread-Spectrum Bible the most complete reference in the field! INCLUDESCD-ROM CONTAININGTHE ENTIRE BOOKIN FULLY-SEARCHABLE PDF Spread-spectrum systems have found important commercial applications in CDMA cellular networks and wireless personal communication networks. Communications engineers and technicians now have ready access to a wealth of spread-spectrum information in this exhaustive handbook the most comprehensive and authoritative compendium on spread-spectrum systems available anywhere. Written by recognized authorities in the field, the Handbook presents both theoretical basics and practical applications, providing succinct, results-oriented solutions to engineering problems. Starting with basic concepts and system models, the book covers: Anti-jamming communication systems Coherent direct-sequence systems Non-coherent frequency-hopped systems Coherent and differentially coherent modulation techniques Pseudonoise acquistion and tracking in direct sequence receivers Time and frequency synchronization of frequency-hopped receivers Low probability of intercept communications In addition, it offers an in-depth look at multiple access communications and positioning systems and discusses the growth of spread-spectrum applications. INCLUDES CD-ROM CONTAINING THE ENTIRE BOOK IN FULLY SEARCHABLE PDF
Download or read book Performance Analysis of Coded Frequency Hopped Spread Spectrum Systems with Unknown Interference written by M. V. Hedge and published by . This book was released on 1987 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two classes of problems are considered. In the first class we model the process of communicating in the presence of interference, which is unknown or hostile, as a two-person zero sum game with the communicator and the jammer as the players. The objective functions we consider are mutual information and the channel cutoff rate. The communicator's strategies are distributions on the input alphabet and on a set of quantizers and the jammer's strategies are distributions on the noise power subject to certain constraints. We consider various conditions on the jammer's strategy set and on the communicator's knowledge. For the case with the decoder uninformed of the actual quantizer chosen, we show that, from the communicator's perspective the worst-case jamming strategy is a distribution concentrated at a finite number of points thereby converging a functional optimisation problem into a nonlinear programming problem. Moreover, we are able to also characterize the worst-case distributions by means of necessary and sufficient conditions which are easy to verify. For the case with the decoder informed of the actual quantizer chosen we are able to demonstrate the existence of saddle-point strategies.
Download or read book Coded FH SS Frequency Hopped Spread Spectrum Communications in the Presenceof Combined Partial Band Noise Jamming Rician Nonselective Fading and Multiuser Interference written by Evaggelos Geraniotis and published by . This book was released on 1987 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report, we address the problem of combatting combined interference in spread-spectrum communication links. We consider frequency-hopped spread-spectrum systems with M-ary FSK modulation and noncoherent demodulation that use forward-error control coding. The interference consists of partial-band noise jamming, nonselective Rician fading, other-user interference, and thermal noise. The coding schemes that we analyze include: Reed-Solomon codes (with or without diversity and error/only), erasure-error or parallel erasure/error decoding); binary, nonbinary, and dual-k convolutional codes with or without side information (information about the state of the channel); and concatenated schemes (Reed-Solomon outer codes with either inner detection-only block codes or inner convolutional codes). In all cases, we derive the minimum signal-to-jammer energy ratio required to guarantee a desirable bit error rate as a function of the fraction of the band that is jammed when the number of interfering users is fixed, and the maximum number of users that can be supported by the system as a function of the fraction of the band that is jammed, when the signal-to-jammer energy ratio is fixed. (Author).
Download or read book Performance Analysis of Both Hybrid and Frequency Hopped Phase coherent Spread Spectrum Systems written by Giovanni Cherubini and published by . This book was released on 1986 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance of Frequency Hopping Spread Spectrum Mobile Radio Systems written by Ramanarayanan Viswanathan and published by . This book was released on 1983 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Performance Study of Modified Frequency Hopping Spread Spectrum Multiple Access Packet Communication Systems written by Ki Jong Hong and published by . This book was released on 1982 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance analysis of frequency hopped spread spectrum communication withworst case jamming interference written by Sang K. Park and published by . This book was released on 1987 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Evaluations of Fast Frequency hopped Spread spectrum Communication Systems with Partial band Noise Jamming and Multitone Jamming written by Kah Chan Teh and published by . This book was released on 1998 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
