Salcedo-Serrano Pedro, Boluda-Ruiz Rubén, Garrido-Balsells José María, Castillo-Vázquez Beatriz, Puerta-Notario Antonio, García-Zambrana Antonio
Telecommunication Research Institute (TELMA), Universidad de Málaga, E-29010 Málaga, Spain.
Sensors (Basel). 2024 Aug 13;24(16):5232. doi: 10.3390/s24165232.
Underwater optical wireless communication (UOWC) systems provide the potential to establish secure high-data-rate communication links in underwater environments. The uniqueness of oceanic impairments, such as absorption, scattering, oceanic turbulence, and air bubbles demands accurate statistical channel models based on empirical measurements for the development of UOWC systems adapted to different types of water and link conditions. Recently, generalized Gamma and a mixture of two generalized Gamma probability density functions (PDF) were proposed to describe the statistical behavior of small and large air bubbles, respectively, when considering several levels of particle-induced scattering. In this paper, we derive novel closed-form analytic expressions to compute the bit error rate (BER) and outage performance using both proposed PDFs for various scattering conditions. Furthermore, simple asymptotic expressions are obtained to determine the diversity order of each scenario. Monte Carlo simulation results verify the obtained theoretical expressions. Our results also reveal that UOWC systems present lower BER and outage performance under more turbid water cases with respect to the tap water case due to the higher diversity order and despite the significant increases in pathloss at short link distances. Particle-induced scattering provides an inherent mechanism of turbid waters to mitigate air bubble-induced fluctuations and light blockages.
水下光无线通信（UOWC）系统为在水下环境中建立安全的高数据速率通信链路提供了潜力。海洋环境中的独特损耗，如吸收、散射、海洋湍流和气泡，需要基于经验测量的精确统计信道模型，以开发适用于不同类型水体和链路条件的UOWC系统。最近，在考虑多级粒子诱导散射时，分别提出了广义伽马分布和两种广义伽马概率密度函数（PDF）的混合分布来描述小气泡和大气泡的统计行为。在本文中，我们推导了新颖的闭式解析表达式，以使用这两种提出的PDF来计算各种散射条件下的误码率（BER）和中断性能。此外，还获得了简单的渐近表达式来确定每种场景的分集阶数。蒙特卡罗仿真结果验证了所获得的理论表达式。我们的结果还表明，由于分集阶数较高，尽管在短链路距离处路径损耗显著增加，但在比自来水更浑浊的水体情况下，UOWC系统的误码率和中断性能更低。粒子诱导散射为浑浊水体提供了一种内在机制，以减轻气泡引起的波动和光阻塞。
