液晶智能超表面辅助的室内可见光通信系统优化设计  

Optimization design of liquid crystal-based reconfigurable intelligent surface-assisted indoor visible light communication systems

作　　者：余礼苏 吕欣欣 钟润 张鸣莉 王正海 王玉皞[1] YU Lisu;LÜXinxin;ZHONG Run;ZHANG Mingli;WANG Zhenghai;WANG Yuhao(School of Information Engineering,Nanchang University,Nanchang 330031,China;Jiangxi Provincial Key Laboratory of Advanced Signal Processing and Intelligent Communications,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学信息工程学院,南昌330031 [2]南昌大学先进信号处理与智能通信江西省重点实验室,南昌330031

出　　处：《工程科学学报》2025年第2期307-314,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(62161023,62061030,62161024);江西省主要学科学术和技术带头人省级人才项目(20232BCJ23085);江西省自然科学基金资助项目(20224BAB212002);中国博士后科学基金资助项目(2021TQ0136,2022M711463);江西省科技研发计划项目(20242BCC32016)。

摘　　要：可见光通信(VLC)作为6G的候选技术,具备广阔的免许可频谱、更高的安全级别、避免射频干扰等诸多优势,这些特点使得VLC成为射频通信的有效补充方案.本文设计并优化了一种基于功率域非正交多址(PD-NOMA)技术的室内VLC下行链路通信系统,该系统中包括一块位于信道中间的同时透射和反射智能超表面(STAR-RIS)和一个基于液晶智能超表面(LC-RIS)的接收器.为了评估所设计的系统性能,本文提出了一个和速率最大化问题,并考虑了实际情况下发射机和接收机之间的视距(LoS)路径存在非用户遮挡因素.由于所提出优化问题的非凸性,首先使用二次变换将目标函数转化为一个分式规划(FP)问题,其次采用分步优化算法和凸优化(CVX)工具来获得可行解.此外,本文分析了发光二极管(LED)的数量、入射光波长以及液晶折射率对室内可见光通信系统和速率的影响.数值仿真结果表明,在能量分裂(ES)操作协议下,STAR-RIS和LC-RIS联合辅助的室内VLC系统的和速率明显高于仅有反射智能超表面(RIS)和无LC-RIS的VLC系统.LED灯数量、入射光波长以及液晶(LC)折射率均会在一定程度上对系统性能产生影响.这些研究结果为室内可见光通信系统的设计和优化提供了重要参考.Visible light communication(VLC)is a promising technology for sixth-generation(6G)networks,offering a broad,license-free spectrum,enhanced security,and protection from radio frequency(RF)interference.This makes VLC an excellent complement to traditional RF communication.VLC is mainly used indoors,typically covering distances ranging between 2 and 5 meters.A major challenge in VLC is increasing data rates,especially when obstacles block the direct line of sight(LoS).To overcome such obstacles,reconfigurable intelligent surfaces(RISs)have been effectively used in wireless networks.Meta-surface-based simultaneous transmission and reflection reconfigurable intelligent surfaces(STAR RISs)have emerged to address LoS blockage and provide 360°coverage in radio-frequency wireless systems.The latest advancement is the proposal of optical simultaneous transmission and reflection reconfigurable intelligent surfaces for VLC systems.Liquid crystal(LC)RISs can electronically tune their physicochemical properties,such as the refractive index,by altering the orientation of the LC molecules using an external electric field.This fine-tuning capability enables LC RISs to precisely direct incident light beams,ensuring that the refracted beams perfectly align with the photodetector’s field of view.This paper introduces a VLC downlink communication system based on indoor power domain non-orthogonal multiple access(PD-NOMA)technology.The system is designed and optimized to include a STAR RIS in the channel and LC RIS-based receivers with co-assisted composition.By utilizing the energy splitting(ES)protocol,STAR RIS is deployed in the transmission channel,while LC RIS-based VLC receivers are employed at the receiver side.Both components significantly enhance the optical signal,improving overall system performance.The system performance is evaluated by solving a sum-rate maximization problem that accounts for practical scenarios such as the presence of nonuser-obscured LoS paths between the transmitter and the receiver.A low-complexity

关 键 词：可见光通信 同时透射和反射智能超表面 液晶智能超表面 功率域非正交多址 分式规划 

分 类 号：TG142.71[一般工业技术—材料科学与工程]