Iterative channel estimation-based soft successive interference cancellation for multiuser underwater acoustic...

Area of Science:

• Underwater Acoustic Communications
• Signal Processing
• Information Theory

Background:

• Underwater acoustic communication systems face significant challenges from multiple access interference (MAI).
• Existing receivers struggle to effectively mitigate MAI in multiuser scenarios.
• Passive time-reversal (PTR) and turbo equalization are advanced techniques for improving communication reliability.

Purpose of the Study:

• To develop a novel single-carrier multiuser receiver for underwater acoustic communications.
• To enhance the performance of receivers in the presence of strong MAI.
• To improve the accuracy of channel estimation and interference reconstruction in iterative receivers.

Main Methods:

• Iterative block-by-block processing combining passive time-reversal (PTR) and direct-adaptation-based turbo equalization.
• Successive interference cancellation (SIC) for initial symbol detection.
• Channel impulse response (CIR) updating using post-SIC signals for improved MAI reconstruction and PTR combination.
• Utilizing a priori symbol information in subsequent iterations to refine MAI and CIR estimates.

Main Results:

• Demonstrated successful recovery of single-carrier nine-user communication data using quadrature phase-shift keying (QPSK).
• Achieved an average data rate of 1.67 kbps per user.
• Experimental validation using data collected at Songhua Lake, China, in 2019 confirmed the receiver's effectiveness.

Conclusions:

• The proposed receiver effectively mitigates MAI in single-carrier multiuser underwater acoustic communication systems.
• The iterative approach combining PTR and turbo equalization significantly enhances communication performance.
• The system offers a viable solution for achieving higher data rates in challenging underwater acoustic environments.