Download or read book Interface Rejection and Channel Equalization Techniques for Direct Sequence Spread Spectrum Systems written by Steven H. Goldberg and published by . This book was released on 1988 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Narrowband Interference Rejection Techniques in Direct Sequence Spread Spectrum Systems written by Ronald Athelstan Iltis and published by . This book was released on 1984 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Knowledge Based Interference Rejection Scheme for Direct Sequence Spread Spectrum Systems written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spread-spectrum signals are used widely in military and commercial communication systems due to their interference rejection capability and their lower probability of interception. In military applications the effects of intentional interference (jamming) are mitigated by the processing gain of the spread-spectrum system. In many spread-spectrum systems, processing gain alone is not sufficient to achieve satisfactory system performance and additional interference rejection techniques need to be employed. The interference suppression circuit is placed prior to the spectrum despreader with the goal of reducing the jammer/interferer energy to an adequately low level that can be handled by the system processing gain. We have presented a novel knowledge-based interference cancellation scheme for direct sequence spread-spectrum systems. This innovative approach utilizes: (1) IPUS, an expert system for the Integrated processing and Understanding of signals, to monitor the communication signal environment in order to determine the parameters of interfering signals within a pre-specified accuracy, and (2) Expert system rules to select from a library of preselected techniques, suitable interference rejection schemes based upon the knowledge obtained from monitoring the signal environment. The effectiveness of this novel interference rejection capability is demonstrated by considering a number of interference scenarios and using the software package SPW(copyright), a time-domain Signal Processing Worksystem.

Download or read book Interference Rejection Techniques to Aid Coarse Acquisition in Direct sequence Spread spectrum written by Lynn Denise Gottesman and published by . This book was released on 1993 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Convex Projections Method for Improved Narrowband Interference Rejection in Direct Sequence Spread Spectrum Systems written by Krishna Rama Narayanan and published by . This book was released on 1994 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Narrowband Interference Rejection in Direct sequence Spread spectrum Systems Using Time Domain Adaptive Filters written by Cheryl L. Stutzmann and published by . This book was released on 1998 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Narrowband Interference Suppression Techniques Using Decision Feedback Filtering in Direct Sequence Spread Spectrum Systems written by Katherine Jauregui Lovette and published by . This book was released on 1994 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Narrow band Interface Rejection in a Ds spread Spectrum Intercept Receiver Using Transform Domain Signal Processing Techniques written by John M. Gevargiz and published by . This book was released on 1987 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Band reject Filtering for Direct sequence Spread Spectrum Communication Systems written by John Edward Uth and published by . This book was released on 1985 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Narrowband Interference Excision in Hybrid Frequency hopping direct sequence Spread spectrum Systems written by Carlos Jaime Chávez and published by . This book was released on 2003 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: A direct-sequence spread-spectrum (DSSS) receiver is vulnerable to being desensitized by high-power narrowband signals within its wide received bandwidth. A solution to this problem is to detect the interfering signals and remove them from the received bandwidth in a process called narrowband interference excision. This can be achieved through a number of existing techniques. However, a hybrid system that utilizes both DSSS and frequency-hopping spread-spectrum (FHSS) techniques complicates the solution. This thesis investigates one technique for narrowband interference excision in the context of such a hybrid frequency-hopping/direct-sequence spread-spectrum (FH/DSSS) system. This technique is based on the discrete Fourier transform (DFT). An overview of DFT-based excision employing an overlap-and-add architecture is given. The critical properties of the window function used are examined, including windowing loss, excision lass, and interference rejection. Finally, the application of DFT-based excision in a hybrid FH/DSSS system is explored.

Download or read book An Alternative Approach to Direct Sequence Spread Spectrum Acquisition written by Eric Neal VanLandingham and published by . This book was released on 2012 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report an alternative approach to Direct Sequence Spread Spectrum acquisition and tracking will be explained and implemented. The system designed uses the impulse response of the channel to acquire and track the time difference between the locally generated pseudonoise code and received signal's pseudonoise code. The results of both simulation and over the air tests confirm the validity of this alternative approach. Several limitations and constraints that are innate in the technique and design used were also identified. Additional research and modifications that would improve the performance of this system are suggested.

Download or read book Excision Techniques in Direct Sequence Spread Spectrum Communication Systems written by and published by . This book was released on 1990 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents a comprehensive summary of a number of methods used in filtering narrowband jammers and interference out of direct sequence spread spectrum communication systems. The basic concept is presented first followed by a discussion of several analog techniques for interference suppression. Most of the emphasis is on digital adaptive methods, which rely on adaptive filtering algorithms. Many of these algorithms are highlighted. This is followed by a discussion on the research which has been conducted in digital excision over the past several years. Two cases based on the author's work are also presented. The first details the performance one can expect from the recursive least squares algorithm when the interferer is a stable tone. An analytical model, which predicts the bit error rate performance for the recursive algorithm under certain conditions, is derived. This model is compared to results obtained from computer simulation, the tracking and filtering capabilities of hte block and recursive least square algorithms when the interference is of the FM-type, i.e., a swept tone having a bandwidth which is approximately 20% of the chip rate. (Author).

Download or read book Signal Processing for Wireless Communication Systems written by H. Vincent Poor and published by Springer Science & Business Media. This book was released on 2006-01-19 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: Signal Processing for Wireless Communication Systems brings together in one place important contributions and up-to-date research results in this fast moving area. The Contributors to this work were selected from leading researchers and practitioners in this field. The book's 18 chapters are divided into three areas: systems, Networks, and Implementation Issues; Channel Estimation and Equalization; and Multiuser Detection. The Work, originally published as Volume 30, Numbers 1-3 of the Journal of VLSI Signal Processing Systems for Signal, Image, and Video Technology, will be valuable to anyone working or researching in the field of wireless communication systems. It serves as an excellent reference, providing insight into some of the most challenging issues being examined today.

Download or read book Filtering of Direct sequence Spread Spectrum Systems with Frequency hop Interference written by John Keelan Grosspietsch and published by . This book was released on 1984 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Techniques for Direct Sequence Spread Spectrum Acquisition written by Alem, Ahmad Waddah Kayyaly and published by . This book was released on 1977 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Receiver Optimization and Error Rates for Pseudo Noise Spread Spectrum Systems with Narrowband Interference Suppression written by John W. Ketchum and published by . This book was released on 1982 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the results of a study of maximum likelihood receiver structures for direct sequence spread spectrum communications over channels with multipath distortion and narrowband interference, and several methods of assessing the bit error probability performance of bit-by-bit receivers and maximum likelihood receivers. This work is a continuation of work which focused on the performance of various methods of suppressing narrowband interference using spectral estimation. The previous work gave performance results in terms of SNR improvement provided by interference suppression. The previous results are extended in this report by deriving a receiver structure based on the maximum likelihood (minimum probability of error) principle. Error probability results given include simulation of a bit-by-bit receiver operated in conjunction with dispersive and nondispersive channels with narrowband interference. Also, a technique for assessing the error rate by averaging conditional probabilities is stated which applies to both fixed nondispersive and fixed dispersive channels, and bit-by-bit and maximum likelihood receivers. Probability of error results obtained using this approach are given. (Author).