Inter-code interference and optimum spreading sequence in frequency-selective Rayleigh fading channels on uplink MC-CDMA

Takashi Shono, Tomoyuki Yamada, Kiyoshi Kobayashi, Katsuhiko Araki, Iwao Sasase

Research output: Contribution to journalArticle

2 Citations (Scopus)


In uplink multicairier code division multiple access (MC-CDMA), the inter-code interference (ICI) caused by the independent and frequency-selective fading channel of each user and the inter-carrier interference caused by the asynchronous reception of each user's OFDM symbols result in multiple access interference (MAI), This paper evaluates the ICI in frequency-selective Rayleigh fading channels for uplink MC-CDMA. We derive theoretical expressions for the desired-to-undesired signal power ratio (DUR) as a quantitative representation of ICI, and validate them by comparison with computer simulations using a Walsh-Hadamard (WH) code. Based on the analytical results, we obtain the optimum spreading sequence that minimizes the ICI (in short, maximizes the multiplexing performance); this sequence appears to be orthogonal. Three equalization combining methods are examined; equal gain combining (EGC), orthogonality restoring combining (ORC), and maximum ratio combining (MRC).

Original languageEnglish
Pages (from-to)1981-1993
Number of pages13
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number8
Publication statusPublished - 2004 Aug



  • Desired-to-undesired signal power ratio
  • Inter-code interference
  • OFDM
  • Spreading sequence

ASJC Scopus subject areas

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics

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