摘要
为克服传统水下弱湍流模型无法准确拟合实测数据的缺陷,选取经实验测试验证的广义Gamma分布(Generalized Gamma Distribution,GGD)来表征弱海洋湍流,并基于此提出综合考虑了GGD弱湍流、零视轴指向误差,以及无衰落信道冲激响应(Fading Free Impulse Response,FFIR)所表征的隐路径损耗和多径效应的新聚合衰落信道模型.接下来,利用Meijer-G函数推导出综合了GGD弱湍流与零视轴指向误差的混合衰落概率密度函数闭型表达,并据此分别推导出并行和串行中继水下无线光通信(Underwater Wireless Optical Communication,UWOC)系统中断概率的理论闭型公式.最后,则利用Monte Carlo数值仿真验证了上述推导的中断概率闭型表达的正确性,并考察不同系统核心参数的选择对中断概率的影响.研究结果表明:中继节点的引入可以有效降低长距离传输时UWOC系统的中断风险;而中继节点数、接收机孔径尺寸、入射光轴抖动方差等参数的选取,皆会对系统的中断性能产生重要影响.此外,光源发散角增大导致的FFIR时延扩展将引发严重的符号间干扰,进而导致系统中断概率普遍下降1~3个数量级.
In order to overcome the shortcoming of the traditional underwater weak turbulence model that cannot accurately fit the measured data,the generalized gamma distribution(GGD)which has been verified by series of laboratory experiments is chosen to characterize the weak oceanic turbulence.Based on this,a new aggregated fading channel model is proposed,which takes into account the GGD weak turbulence,zero boresight pointing error,and the implicit path loss and multipath propagation effect characterized by fading free impulse response(FFIR).Next,a closed-form expression of the hybrid fading probability density function integrating the GGD weak turbulence and zero boresight pointing error is derived using the higher transcendental Meijer-G function,and then,the theoretical closed-form expressions for the outage probabilities of the parallel and serial relaying underwater wireless optical communication(UWOC)systems are derived accordingly.Finally,Monte Carlo simulations are provided to verify the correctness of the above-derived analytical formulas for the outage probability and to investigate the effect of different system core parameters on outage performance of the systems.The results show that the introduction of relay nodes can effectively reduce the outage risk of UWOC over long distances.In contrast,the number of relay nodes,receiver aperture size,incident optical beam jitter variance,and other parameters can affect the outage performance.In addition,the FFIR delay spread caused by increasing of the divergence angle of the light source will lead to serious inter-symbol interference,which will result in a general decrease of 1~3 orders of magnitude in the outage performance of the relaying UWOC systems.
作者
张馨文
李岳衡
江雨薇
居美艳
黄平
ZHANG Xin-wen;LI Yue-heng;JIANG Yu-wei;JU Mei-yan;HUANG Ping(Hohai University,Nanjing,Jiangsu 211100,China)
出处
《电子学报》
EI
CAS
CSCD
北大核心
2023年第11期3294-3304,共11页
Acta Electronica Sinica
基金
国家自然科学基金(No.61832005)。
关键词
广义Gamma分布
弱海洋湍流
指向误差
中继
中断概率
水下无线光通信
generalized gamma distribution
weak oceanic turbulence
pointing error
relay
outage probability
underwater wireless optical communication
