同信道干扰下RIS辅助FSO-RF混构系统性能分析  

Performance Analysis of RIS-Assisted FSO-RF Hybrid Systems Under Co-Channel Interference

作　　者：曹阳 包朝园 彭小峰 邢雯珺 Cao Yang;Bao Chaoyuan;Peng Xiaofeng;Xing Wenjun(School of Electrical and Electronic Engineering,Chongqing University of Technology,Chongqing 400054,China)

机构地区：[1]重庆理工大学电气与电子工程学院,重庆400054

出　　处：《光学学报》2024年第6期209-217,共9页Acta Optica Sinica

基　　金：重庆市教委科学技术项目(KJQN201901125);重庆市科委社会事业与民生保障科技创新专项(cstc2017shmsA40019);重庆市基础与前沿研究计划项目(cstc2019jcy-msxm X0233);重庆理工大学研究生教育高质量发展行动计划(gzlcx20223041)。

摘　　要：针对自由空间光(FSO)通信无法进行视距传输的问题,在FSO链路中引入可重构智能表面(RIS)技术,并考虑射频(RF)链路中的同信道干扰(CCI)信号,提出一种CCI下RIS辅助FSO-RF混构系统研究方案。其中FSO链路和RF链路分别服从Gamma-Gamma分布和Rayleigh分布,在光电转换中继节点处采用译码转发协议,以减少噪声对信号的干扰。基于系统端到端瞬时信噪比的概率密度函数,推导了系统中断概率和平均误码率的闭合表达式,采用蒙特卡罗仿真验证了结果的准确性。研究结果表明,相较于传统的混合FSO/RF系统,RIS能明显提升系统的性能。另外,根据系统的分集顺序,得出系统的性能主要与FSO链路的衰落参数、光检测方式和指向误差有关。Objective The problems of spectrum limitations and co-channel interference(CCI)in radio frequency(RF)communication systems have limited the development of high-speed rate services.At the same time,free-space optical(FSO)communication is complementary to RF communication because it does not require a spectrum license and is highly resistant to interference.However,FSO communication is susceptible to atmospheric turbulence and pointing errors,which can deteriorate the communication link and even cause disruptions.In order to improve the performance of FSO systems,traditional solutions use spatial diversity,aperture averaging,and FSO-RF hybrid systems.Based on the FSORF hybrid system,we introduce reconfigurable intelligent surface technology in the FSO link to solve the problem of FSO being unable to carry out line-of-sight communication.Considering the CCI problem in the RF link,we propose a reconfigurable intelligent surface(RIS)-assisted FSO-RF hybrid system scheme under CCI,which further improves the performance of the system compared with the traditional FSO/RF scheme.Methods We present a scheme for a hybrid FSO-RF system under CCI.Firstly,reconfigurable smart surface techniques are introduced in the FSO link for the case where line-of-sight transmission is not possible for FSO communication,and CCI signals in the RF link are considered.The FSO link obeys the Gamma-Gamma distribution,and the RF link obeys the Rayleigh distribution.In addition,a decode-and-forward protocol is used at the optoelectronic switching relay node.Then,based on the probability density function of the system end-to-end instantaneous signal-to-noise ratio(SNR),closed-form expressions for the system outage probability and average bit error rate(BER)are derived,and Monte Carlo simulation is used to verify the accuracy of the results.Finally,the corresponding conclusions are drawn based on the diversity order of the system.Results and Discussions With a fixed average SNR of the FSO link,the outage probability performance of the system deteri

关 键 词：光纤光学 可重构智能表面 同信道干扰 中断概率 平均误码率 译码转发协议 

分 类 号：TN929.12[电子电信—通信与信息系统]