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Iterative-detection-based time-domain adaptive decision feedback equalization for continuous phase modulation of
Ruigang Han1,2,3, Ning Jia1,2,3, Yunfei Li1,2,3
1Institute of Acoustics, Chinese Academy of Sciences, Beijing, 100190, China.
The Journal of the Acoustical Society of America
|March 19, 2025
Summary
Continuous phase modulation (CPM) offers efficiency for underwater acoustic (UWA) communications. A new iterative-detection-based time-domain adaptive decision feedback equalization (ID-TDADFE) algorithm significantly improves UWA communication performance by reducing bit errors.
Area of Science:
- Electrical Engineering
- Signal Processing
- Underwater Communications
Background:
- Continuous Phase Modulation (CPM) is efficient for aviation and satellite systems.
- Conventional frequency-domain equalization (FDE) struggles with time-varying underwater acoustic (UWA) channels.
- Existing time-domain equalization algorithms often use approximations, degrading symbol detection.
Purpose of the Study:
- To introduce an iterative-detection-based time-domain adaptive decision feedback equalization (ID-TDADFE) algorithm.
- To enhance symbol detection performance in UWA communication systems using CPM signals.
- To address performance degradation caused by time-varying UWA channels.
Main Methods:
- Developed an ID-TDADFE algorithm for symbol-by-symbol detection.
- Incorporated joint probability estimation to enhance symbol detection.
- Evaluated performance using minimum-shift keying (MSK) and Gaussian MSK signals.
Main Results:
- ID-TDADFE significantly improved communication performance over time-varying UWA channels within 1-2 iterations.
- Numerical simulations showed substantial gains compared to conventional methods.
- A sea trial demonstrated a 45.08% and 51.8% reduction in bit errors after the first and second iterations, respectively, compared to FDE.
Conclusions:
- The proposed ID-TDADFE algorithm effectively tracks channel variations in UWA systems.
- It enhances symbol detection by leveraging CPM's coding gain and joint probability estimation.
- ID-TDADFE offers a superior solution for reliable UWA communication with CPM signals.
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