Wide dynamic range signal detection for underwater optical wireless communication using a PMT detector

Area of Science:

• Photonics
• Optical Communications
• Signal Processing

Background:

• Underwater optical wireless communication (UOWC) systems face challenges due to wide dynamic range of incident optical power.
• Photomultiplier tubes (PMTs) are used as detectors but operate across pulse, transition, and waveform regimes, complicating signal analysis.

Purpose of the Study:

• To develop advanced symbol detection methods for UOWC systems using PMTs.
• To improve the accuracy and robustness of UOWC signal detection under varying conditions and ambient radiation.

Main Methods:

• Experimental measurements of upsampled discrete signal samples within a symbol duration.
• Fitting the probability density function (PDF) using generalized extreme value (GEV) distribution.
• Proposing joint sample distribution (JSD) and superimposed sample distribution (SSD) based detection methods using GEV and log-likelihood ratio (LLR) testing.

Main Results:

• GEV distribution accurately fits the PDF of signal samples across different PMT operating regimes.
• Proposed JSD and SSD methods outperform traditional Poisson and Gaussian-based maximum likelihood detection.
• Effectiveness demonstrated in alleviating strong ambient radiation interference.

Conclusions:

• GEV distribution-based methods offer a robust approach for symbol detection in UOWC.
• The proposed methods significantly enhance UOWC system performance, extending transmission capabilities.
• This research contributes to more reliable underwater communication systems.