CDMA COMMUNICATION SYSTEM

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CDMA COMMUNICATION SYSTEM

• Signaler, Sensorer System

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Project Organisation
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Project Goals

• Implementation of a real-time digital acoustic
• communication system using CDMA.
• The system should work reliably in a multipath
• environment.
• The system should allow for different coding gain
  to illustrate
• the trade-off between data rate and robustness
  to interference.

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What is CDMA?

• Code Division Multiple Access
• Multiple users utilizing the same bandwidth
• Each user is allocated a unique code sequence
• Robust towards interference

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Spreading the Signal
c(t)
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PN signal
t
-1
v(t)
1
Data signal
t
-1
v(t)c(t)
1
Product signal
t
-1
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Spreading Effects on Interference
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BPSK Modulation

• Why Choose BPSK?
• Easy to implement
• Well suited for CDMA

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Choise of Carrier Frequency
White noise Ambiance
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Communication System
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Results
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Results

• Maximum transmitted chip rate
• Matlab 8000 chip/s
• DSP 4000 chip/s
• Maximum transmitted information bit rate
• Matlab 1000 bits/s
• DSP 500 bits/s

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Possible Improvments

• Decision on each chip
• Multiple user implementation
• Using old equalizer coefficients to
• equalize the training sequence
• before synchronization

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User Interface