Guangtongxin yanjiu (Aug 2025)
Bit Error Rate Analysis of Underwater Photon-counting Communication System based on Joint Channel
Abstract
【Objective】Underwater Photon Counting Wireless Communication (UPCC) is capable of achieving weak signal detection. It can effectively mitigate the impact of optical signal attenuation induced by complex underwater environments and extend the communication range. The absorption and scattering of light in underwater channels lead to signal attenuation, while turbulence gives rise to fluctuations in signal amplitude. Both of these phenomena can degrade the Bit Error Rate (BER) of the UPCC systems. It is crucial to reasonably evaluate the comprehensive impact of these factors on the bit error performance of the UPCC system based on the underwater joint channel model that takes into account the effects of absorption, scattering and turbulence simultaneously.【Methods】In this study, the random phase screen model is employed to simulate the impact of turbulence effects on the transmitted beam. The turbulence phase screen model is further extended to the Monte Carlo (MC) numerical simulation framework for underwater channels. Subsequently, a more comprehensive joint channel model of absorption, scattering, and turbulence, incorporating the influence of the seawater environment, is constructed. Additionally, based on the Single-Photon Avalanche Diode (SPAD) and On-Off Keying (OOK) modulation methods, an UPCC system is developed.【Results】Utilizing the established joint channel model, a comparative analysis is conducted on the bit error performance of the UPCC system under diverse parameters, including water quality conditions, link distance, and turbulence intensity.【Conclusion】The results of the simulation indicate that in the environments of pure seawater and clean seawater with excellent water quality, the impact of turbulence on the communication performance of the system cannot be ignored. Specifically, the communication distance is significantly attenuated, and the BER of the system increases. For instance, under the ideal conditions of pure seawater and the absence of turbulence, the maximum communication distance of the system can reach approximately 500 m. Under weak turbulence, it reduces to about 400 m, and under strong turbulence, it further shrinks to approximately 200 m. As the water quality deteriorates, the absorption and multiple scattering effects emerge as the primary factors influencing the communication performance of the system. In the seawater of the port with the poorest water quality, the farthest communication distance of the system under different turbulence intensities ranges from approximately 25~30 m. Moreover, the influence of different turbulence intensities on the BER of the system is nearly negligible.
