Interference Effects in Direct Sequence Spread Spectrum Communications Systems PDF Download

Author: Ward James Davies
Publisher:
ISBN:
Category : Electromagnetic interference
Languages : en
Pages : 366

View

Book Description

Author: Christopher Lance Johnson
Publisher:
ISBN:
Category :
Languages : en
Pages : 232

View

Book Description

Author: Matthew G. Glen
Publisher:
ISBN: 9781423519928
Category : Coding theory
Languages : en
Pages : 78

View

Book Description
This research characterizes MAI effects on DS/SSMA system performance through simulation in Matlab , and explores the impact of multiple access code selection, chip waveform shaping, and multiple access code length on BER for both synchronous and asynchronous multiple access networks. In addition, the simulated DS/SSMA model permits rapid research into the effects of additional factors on BER. Prior to experimental testing, model validation is conducted through single user trials and by comparison with existing research for similar system designs. For synchronous and asynchronous networks, Gold coding improves BER by 7.5 and 4.0 dB, respectively, relative to aperiodic random spreading codes. Synchronous network results show that chip waveform shaping provides no significant BER improvement for the Blackman or Lanczos shapes. However, asynchronous network results show a potential BER improvement for Blackman and Lanczos shapes. Increasing code length from 31 to 511 resulted in a 7.5 dB BER improvement. Collectively, these results directly relate changes in BER to waveform cross-correlation statistics.

Author: Robert Clyde Dixon
Publisher: Wiley-Interscience
ISBN:
Category : Science
Languages : en
Pages : 544

View

Book Description

Author: Leonard Farber
Publisher:
ISBN:
Category :
Languages : en
Pages : 73

View

Book Description
A computer simulation model developed for determining the manner in which undesired spread spectrum signals affect the performance of conventional narrowband AM and FM voice communication systems is described. Direct-sequence, frequency-hopping and hybrid, frequency-hopping/direct-sequence, spread spectrum interference signals were modeled. Binary phase-shift keying and minimum-shift keying were included for the carrier modulation of the direct-sequence signals and the direct-sequence portion of the hybrid signals. In addition to the spread spectrum interference, pulsed interference and white Gaussian noise were modeled. Using articulation index as the measure of performance, comparisons are made between system performance for direct-sequence interference and white Gaussian noise. System performance for frequency-hopping or frequency-hopping/direct-sequence interference is compared with that for pulsed interference. (Author).

Author: Brian William Kozminchuk
Publisher:
ISBN:
Category : Algorithms
Languages : en
Pages : 476

View

Book Description

Author:
Publisher:
ISBN:
Category : Communications, Military
Languages : en
Pages : 0

View

Book Description
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.

Author: Roger L. Peterson
Publisher: Pearson
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 718

View

Book Description
Besides the traditional military application areas, there is a growing and intense interest in spread spectrum communications systems for evolving civil applications, e.g., cellular-mobile communications, personal communications, and satellite-mobile communications. Ideal for those who need to get up to speed or current quickly in this area, this self-contained exploration of spread spectrum system analysis and applications provides a solid theoretical background along with an abundance of examples of specific analysis/design situations, and exposes readers to the most recent research and developments in the field. Covers basic digital communication and spread spectrum concepts, and features exceptionally complete treatments of important hot topics such as spectrum spreading sequences; the code acquisition and tracking process; the effects of jamming on spread spectrum communications and the use of coding/interleaving to combat the detrimental effects of jamming; designing spread spectrum systems for low probability of the intercept; and the design of code division multiple access systems, wit h examples. Contains a complete set of technical appendices. For electrical engineers and others with a background in linear systems and probability/random processes who want a cutting-edge overview of the principles, research, and developments of spread spectrum systems.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
This report presents research results focused on the mitigation of both narrowband and multiple access interference in direct sequence spread spectrum communication systems. Both linear and nonlinear adaptive algorithmic approaches are developed and reported. Specific attention has been paid to making the algorithmic practicable. In addition to the algorithmic development, a software simulation for a code division multiple access system is developed using a commercially available programming environment.

Author: John R. Juroshek
Publisher:
ISBN:
Category : Television
Languages : en
Pages : 44

View

Book Description