CDMA

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CDMA

• Motohiro Ichinose

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CDMA

• Code Division Multiple Access (CDMA)
• A digital wireless technology that uses a "spread
  spectrum" technique to scatter a radio signal
  across a wide range of frequencies. CDMA provides
  greater total capacity than other technologies,
  along with outstanding voice quality and fewer
  dropped calls. CDMA is the technology of choice
  for new third-generation systems

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CDAM (history)

• CDMA is a military technology first used during
  World War II by the English allies to foil German
  attempts at jamming transmissions. The allies
  decided to transmit over several frequencies,
  instead of one, making it difficult for the
  Germans to pick up the complete signal.

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CDMA(code division multiple access)
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Advantage of using CDMA

• Noise reduction
• Secrecy

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Spread singnal
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How to spread
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Transmit, receive and noise reduction
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IMT-2000 begins last year

• Celluer phone 9.6kbps
• Foma (w-cdma) 384kbps
• 2Mbps