广义发射激光选择下的FSO-VUWOC混合系统中断概率分析  

Outage⁃Probability Analysis of Mixed FSO⁃VUWOC Systems with Generalized Transmit⁃Laser Selection

作　　者：张琦 岳殿武[1] 赵公诺 徐宪莹 Zhang Qi;Yue Dianwu;Zhao Gongnuo;Xu Xianying(College of Information Science and Technology,Dalian Maritime University,Dalian 116026,Liaoning,China;School of Information Science and Engineering,Dalian Polytechnic University,Dalian 116034,Liaoning,China)

机构地区：[1]大连海事大学信息科学技术学院,辽宁大连116026 [2]大连工业大学信息科学与工程学院,辽宁大连116034

出　　处：《中国激光》2024年第23期82-94,共13页Chinese Journal of Lasers

基　　金：国家自然科学基金(62301108);辽宁省科技计划(2023JH26/10300010)。

摘　　要：无线光通信(WOC)作为一种高速、可靠的通信技术,成为实现陆上与水下无线连接的一种有吸引力的解决方案。无论是陆上还是水下环境,湍流衰落对WOC系统的性能都有很大影响。发射激光选择(TLS)作为减轻湍流衰落的有效技术而被提出。对于理想假设下的传统TLS,在多个候选激光源中,选择具有最高瞬时接收信噪比(SNR)的激光源(最佳激光源)来传输信号,但实际上,信道估计和反馈误差导致选择次优或更差的光源。因此,提出广义发射激光选择(GTLS)下的自由空间光(FSO)通信与垂直水下无线光通信(VUWOC)混合(FSOVUWOC)系统来实现陆海一体化通信,其中GTLS考虑实际场景下各种误差导致选择非最佳光源的情况。首先,基于Gamma-Gamma分布的大气湍流信道和多层级联垂直水下湍流信道,利用Meijer G函数和Gauss超几何函数,推导GTLS下FSO-VUWOC系统的闭式中断概率表达式。然后,利用高信噪比(SNR)条件下的中断概率渐近分析,得到了FSO-VUWOC系统的分集阶。最后,通过数值仿真验证上述推导结果,结果表明,与不具备GTLS的FSO-VUWOC系统相比,GTLS系统具有更好的中断概率性能表现,例如GTLS系统(光源数为5)在不同光源索引下,为实现10-3的目标中断概率,所需的平均SNR分别降低了33.0 dB(最佳光源)、27.0 dB(第二最佳光源)、20.5 dB(第三最佳光源)和11.5 dB(第四最佳光源)。除了选择光源索引外,VUWOC和FSO链路距离以及光源数量亦显著影响GTLS系统的性能。Objective In recent years,wireless optical communication(WOC)has received increasing attention.WOC is applicable to diverse applications,including those pertaining to terrestrial and underwater communications.Terrestrial WOC is similarly known as freespace optical(FSO)communication.Compared with the existing radio frequency(RF)communication system,FSO systems offer the advantages of large bandwidth,high data rate,reusable equipment and wavelength,high security,and anti-electromagnetic interference.WOC applied in an underwater environment is known as underwater wireless optical communication(UWOC).Compared with underwater acoustic and underwater RF communications,UWOC offers a higher transmission rate,lower link delay,and lower implementation cost.Whether on land or underwater,turbulence fading significantly affects the performance of WOC systems.Transmit-laser selection(TLS)has been proposed as an effective technique for mitigating fading.For the typical TLS under ideal assumptions,the laser source with the highest instantaneous received signal-to-noise ratio(SNR),i.e.,the best laser source,is selected for signal transmission.However,a suboptimal or worse source may be selected owing to channel-estimation and/or feedback errors.Additionally,to accommodate deep-ocean explorations,land platforms may be required to transmit information to underwater platforms through reliable wireless links,which are typically vertical links.Therefore,in this study,we propose a mixed communication system(FSO-VUWOC)comprising FSO communication and vertical UWOC(VUWOC)with generalized transmitlaser selection(GTLS)to realize land and ocean integrated communication.The GTLS considers the selection of non-optimal light sources due to various errors in the actual scene.Methods First,considering the atmospheric turbulence channel and the multilayer cascade vertical underwater turbulence channel based on a gamma-gamma distribution,as well as applying the Meijer G function and Gauss hypergeometric function,we derive the closed-form outage-pr

关 键 词：发射激光选择 自由空间光通信 水下无线光通信 中断概率 分集阶 

分 类 号：TN929.1[电子电信—通信与信息系统]