A Knowledge-Based Interference Rejection Scheme for Direct-Sequence Spread-Spectrum Systems

Abstract

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.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1999
Accession Number
ADA362918

Entities

People

  • D. D. Weiner
  • I. Demirkiran
  • P. K. Varshney
  • S. H. Nawab
  • V. N. Samarasooriya

Organizations

  • Syracuse University

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Communication Systems
  • Computer Programming
  • Computer Programs
  • Computer Science
  • Computers
  • Databases
  • Digital Information
  • Expert Systems
  • Filtration
  • Frequency
  • Frequency Bands
  • Modulation
  • Signal Generators
  • Signal Processing
  • Spread Spectrum
  • Time Domain

Fields of Study

  • Engineering

Readers

  • Artificial Intelligence
  • Radio communications and signal processing.