In this letter, a performance study of a mixed dual-hop communication system consisting of free-space optical/underwater wireless optical communication (FSO-UWOC) links is presented. In particular, considering both heterodyne detection and intensity modulation with direct detection (IM/DD), we assume that the FSO channel suffers a Gamma-Gamma fading in the presence of pointing error impairments, while the UWOC channel experiences a mixture Exponential-Generalized Gamma (EGG) fading with pointing errors. Assuming a fixed-gain amplify-and-forward (AF) protocol, closed-form expressions for the outage probability, average bit-error-rate, and average capacity in terms of the bivariate Fox’s H-function are derived. To verify the derived analytical expressions, numerical results are provided to verify the accuracy of our results.

中文翻译：

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关于混合 FSO-UWOC 双跳传输系统的性能

在这封信中，介绍了由自由空间光/水下无线光通信 (FSO-UWOC) 链路组成的混合双跳通信系统的性能研究。特别是，考虑外差检测和带直接检测的强度调制 (IM/DD)，我们假设 FSO 信道在存在指向错误损伤的情况下遭受 Gamma-Gamma 衰落，而 UWOC 信道经历混合指数-广义 Gamma (EGG) 因指向错误而衰落。假设一个固定增益放大转发 (AF) 协议，根据双变量 Fox 的 H 函数导出中断概率、平均误码率和平均容量的封闭形式表达式。为了验证导出的解析表达式，提供了数值结果来验证我们结果的准确性。