Broadband CDMA techniques

Fumiyuki Adachi, Deepshikha Garg, Shinsuke Takaoka, Kazuaki Takeda

Research output: Contribution to journalReview articlepeer-review

251 Citations (Scopus)


A very high-speed wireless access of 100 Mb/s to 1 Gb/s is required for fourth-generation mobile communications systems. However, for such high-speed data transmissions, the channel is severely frequency-selective due to the presence of many interfering paths with different time delays. A promising wireless access technique that can overcome the channel frequency-selectivity and even take advantage of this selectivity to improve the transmission performance is CDMA. There may be two approaches in CDMA technique: direct sequence CDMA and multicarrier CDMA. A lot of attention is paid to MC-CDMA. However, recently it has been revealed that DS-CDMA can achieve good performance comparable to MC-CDMA if proper frequency domain equalization is adopted. This article discusses their similarities and performances. A major transmission mode in 4G systems will be packet-based. Automatic repeat request combined with channel coding is a very important technique. Recent research activity on this technique is also introduced.

Original languageEnglish
Pages (from-to)8-18
Number of pages11
JournalIEEE Wireless Communications
Issue number2
Publication statusPublished - 2005 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering


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