同信道干扰下RIS辅助MUD-RF/FSO混构系统性能分析  

Performance Analysis of RIS-Assisted MUD-RF/FSO Hybrid System Under Co-Channel Interference

作　　者：包朝园 曹阳 彭小峰 邢雯珺 Bao Chaoyuan;Cao Yang;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》2023年第22期108-116,共9页Acta Optica Sinica

基　　金：重庆市教委科学技术项目(KJQN201901125);重庆市教委基金(KJ120827);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);重庆市研究生科研创新项目(CYS23667)。

摘　　要：为了解决射频(RF)通信中存在的同信道干扰问题,利用多用户的同时传输产生分集增益,并考虑自由空间光(FSO)通信无法完成视距传输的问题,在FSO链路中引入可重构智能表面(RIS)技术,提出一种同信道干扰下RIS辅助多用户分集(MUD)-RF/FSO混构系统方案。其中,具有多用户分集的RF链路服从独立同分布的Rayleigh分布,光学RIS辅助的FSO链路服从Gamma-Gamma分布,在电光转换中继节点处采用译码转发协议。基于系统端到端瞬时信噪比的概率密度函数及其累计分布函数,推导了系统中断概率和平均误码率的闭合表达式。仿真结果表明,RIS可以显著提升MUD-RF/FSO混构系统的性能。此外,用户数量的增加可以为系统带来分集增益,从而抑制同信道干扰所带来的不良影响。Objective Research on hybrid dual-hop radio frequency(RF)/free-space optical communication systems can improve the multipath fading robustness and communication coverage.However,since the co-channel interference problem in RF communication systems cannot be ignored,the adoption of a multi-user diversity scheme can improve the adverse interference effect and enhance the system performance.Meanwhile,optical reconfigurable intelligent surface(RIS)is introduced in the free-space optical(FSO)communication link to enhance the signal quality when the FSO communication cannot fulfill the conditions of line-of-sight communication.Methods To improve the co-channel interference in RF communication,we utilize the simultaneous transmission of multiple users to generate diversity gain and consider the problem that FSO communication cannot complete line-of-sight transmission.Additionally,RIS technology is introduced in the FSO link to put forward a scheme of RIS-assisted MUDRF/FSO hybrid system under co-channel interference.The RF link with multi-user diversity obeys the independent homogeneous Rayleigh distribution,the optical RIS-assisted FSO link obeys the Gamma-Gamma distribution,and the decode-and-forward protocol is adopted at the electro-optical conversion relay node.Based on the probability density function(PDF)of the system's end-to-end instantaneous signal to noise ratio(SNR)and its cumulative distribution function(CDF),closed expressions for the system outage probability and average bit error ratio(BER)are derived.Simulation results show that RIS can significantly improve the performance of the MUD-RF/FSO hybrid system,and the increasing user number can bring diversity gain to the system,thus suppressing the undesirable effects caused by co-channel interference.Results and Discussions In strong turbulence conditions,the SNR of the FSO link is fixed at 50 dB to study the effect of different L and M on the outage probability of the system.The outage probability performance of the system is dramatically improved when th

关 键 词：多用户分集 可重构智能表面 中断概率 平均误码率 同信道干扰 

分 类 号：TN929.12[电子电信—通信与信息系统]