Simplified Detection Techniques For Serially Concatenated CodedContinuous Phase Modulations Dileep K

1
Simplified Detection Techniques For Serially
Concatenated Coded-Continuous Phase Modulations
Dileep Kumaraswamy dileep_at_ittc.ku.edu, Erik
Perrins esp_at_eecs.ku.edu
Advantages of SCC-CPMs
Serial Concatenation of CPM

• Very high coding gains mean low operative Eb/No
• Approaches ML decoding at much lower complexity

n(t)
Noise
Input Bits
CPM Modulator
Problems to be addressed
Interleaver
CC
u
c
r (t)
Matched Filtering

• Need for Simpler Detection Techniques Bandwidth
  Efficiency trades off Detection Complexity in
  bandwidth efficient CPMs.
• Problems with coherent detection at low Eb/No-
  false locks, Doppler shifts, phase slips due to
  fading, frequency jitters
• Some challenges encountered in improving
  detection
• Reducing latency and complexity smaller trellis
  and simpler non-coherent metric (exponential
  window)
• Resolving the unknown carrier phase
• Non-coherent detection in the presence of phase
  noise

SISO (CPM)
De-Interleaver
C1
SISO (CC)
Decoded Bits
C2
Interleaver
Techniques Adopted
Performance Results

• Non Coherent Detection
• Heuristic (and practical) versus Optimal
• Trellis Reduction
• Decision Feedback
• Pulse Truncation

• 8 state detector is less than half the complexity
  of optimal detector at an expense of just 0.17 dB
  power
• Non-coherent detector with a phase noise of 2
  degrees/symbol is just 0.35 dB worse than the
  coherent detection