光子学报, 2018, 47 (11): 1106003, 网络出版: 2018-12-17
基于空间分集的海洋无线光通信轨道角动量复用系统的性能
Performance of Oceanic Wireless Optical Communication Systems Based on Orbital Angular Momentum Multiplexing with Spatial Diversity
无线通信技术 湍流缓解 复用系统 等增益分集合并 海洋湍流 轨道角动量 传输距离 误码率 Wireless communications technology Turbulence mitigation Multiplexing system Equal gain spatial diversity combination Oceanic turbulence Orbital angular momentum Transmission distance Bit error rate
摘要
为了解决水下通信轨道角动量复用系统中海洋湍流引起的信号串扰, 基于空间分集技术提出了一种海洋湍流缓解方案.用随机相位屏法模拟海洋湍流对信号产生的相位扰动, 用分步传输法模拟光束的衍射传播, 在接收端使用等增益分集合并技术对信号进行合并处理.系统采用4路轨道角动量复用8路空间分集, 仿真分析了轨道角动量复用集合、海洋湍流强度和传输距离等因素对系统误码率性能的影响.仿真结果表明, 轨道角动量复用集合的模式间隔从1增加到2, 误码率降低较为明显; 随着模式间隔继续增大, 误码率性能改善有限; 误码率随传输距离和湍流强度的增加而增大.结果证明在海洋光通信系统中使用分集合并技术可以有效缓解湍流对信号传输的影响.
Abstract
In oceanic wireless optical communication systems based on orbital angular momentum multiplexing, oceanic turbulence will bring the channel crosstalk. To solve the problem of channel crosstalk, a spatial diversity mitigation scheme is proposed. Random phase screen method is used to simulate phase perturbation caused by ocean turbulence and split-step transmission method is used to simulate the beam diffraction. Equal gain diversity combination is used to process signal at the receiver. 4-orbital angular momentum-multiplexed channels and 8-spatial diversity are used in the system. The influences of orbital angular momentum mode sets, oceanic turbulence strength and communication distance on the bit-error rate are investigated. Simulation results show that bit error rates decrease obviously with the modes spacing increases from 1 to 2 in the orbital angular momentum multiplexed sets. Performances of bit-error rates remain steady as modes spacing become larger. Bit-error rate will also increase with the increasing transmission distance and turbulence strength. Results show using diversity combination on orbital angular momentum-multiplexed systems can effectively mitigate the performance degradation from oceanic turbulence.
尹霄丽, 孙志雯, 崔小舟, 郑子健, 陈小政, 郭翊麟, 廖焕宇, 刘光耀. 基于空间分集的海洋无线光通信轨道角动量复用系统的性能[J]. 光子学报, 2018, 47(11): 1106003. YIN Xiao-li, SUN Zhi-wen, CUI Xiao-zhou, ZHENG Zi-jian, CHEN Xiao-zheng, GUO Yi-lin, LIAO Huan-yu, LIU Guang-yao. Performance of Oceanic Wireless Optical Communication Systems Based on Orbital Angular Momentum Multiplexing with Spatial Diversity[J]. ACTA PHOTONICA SINICA, 2018, 47(11): 1106003.