Optimal design of phase function in Generalized DFT

Ali N. Akansu, Handan Agirman-Tosun, Mustafa U. Torun

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Recently, a theoretical framework for Generalized DFT (GDFT) with nonlinear phase functions exploiting the phase space to design various constant modulus orthogonal transforms was introduced. This paper extends prior work to design longer bases widely used in real world communications systems. GDFT provides flexibilities in phase space yielding performance improvements over other code families including DFT in correlation metrics. GDFT phase functions are optimally designed in order to reduce inter carrier interference (ICI) and inter-symbol interference (ISI) that dictate the performance of a multiuser channel. It is presented in the paper that superior correlation of GDFT over DFT manifests itself in improved BER performance in direct sequence CDMA based multi-user communications systems.

Original languageEnglish (US)
Pages (from-to)255-264
Number of pages10
JournalPhysical Communication
Issue number4
StatePublished - Dec 2010

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


  • Auto-correlation function
  • Cross-correlation function
  • Direct Sequence Code Division Multiple Access (DS/CDMA)
  • Discrete Fourier Transform (DFT)
  • Generalized Discrete Fourier Transform (GDFT)
  • Gold codes
  • Walsh codes


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