Wavelet Packets in Wideband Multiuser Communications

Abstract

Throughout the entire duration of this contract, the contractor has accomplished a number of tasks. First, we modeled communications channels using wavelet packets, for both time-invariant and time-varying channels. We then developed doubly orthogonal CDMA user spreading waveforms based on wavelet packets. We have also developed and evaluated a wavelet packet based multicarrier CDMA wireless communication system. In this system design a set of wavelet packets are used as the modulation waveforms in a multicarrier CDMA system. The need for cyclic prefix is eliminated in the system design due to the good orthogonality and time-frequency localization properties of the wavelet packets. Two new detection algorithms are developed to work in either time domain or wavelet packet domain to combat multiuser and inter symbol interferences. Compared with the existing DFT based multicarrier CDMA systems, better performance is achieved with the wavelet packet based system by utilizing the saved cyclic prefix overhead for error correction coding. Theoretical analyses as well as computer simulations are performed to support these claims.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 2004
Accession Number
ADA428785

Entities

People

  • Howard Fan

Tags

Communities of Interest

  • C4I
  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Algorithms
  • Communication Channels
  • Communication Systems
  • Computational Complexity
  • Computational Science
  • Detection
  • Frequency
  • Frequency Bands
  • Modulation
  • Multiple Access
  • Orthogonal Frequency Division Multiplexing
  • Random Variables
  • Simulations
  • Time Domain
  • Time-Varying Channels
  • Wireless Communications

Fields of Study

  • Engineering

Readers

  • Image Processing and Computer Vision.
  • Radio communications and signal processing.