基于IRS辅助的OFDM-IM系统设计  

Design of OFDM-IM system based on IRS-assisted

作　　者：赵萌萌 何立明[1] 刘芳芳 ZHAO Mengmeng;HE Liming;LIU Fangfang(School of Information Engineering,Chang’an University,Xi’an 710064,China)

机构地区：[1]长安大学信息工程学院,陕西西安710064

出　　处：《电信科学》2023年第7期59-67,共9页Telecommunications Science

基　　金：国家自然科学基金资助项目(No.51308058)。

摘　　要：索引调制(index modulation,IM)和智能反射面(intelligent reflecting surface,IRS)是新兴的移动通信技术。为了提高传统正交频分复用(orthogonal frequency division multiplexing,OFDM)系统的可靠性,设计一种基于IRS的索引调制正交频分复用(orthogonal frequency division multiplexing-index modulation,OFDM-IM)系统。首先,使用空间调制和频域调制设计OFDM-IM系统,增大子载波间的欧几里得距离。其次,通过建立等效电路模型,设计实用的IRS模型。最后,使用交替优化算法联合优化接入点(access point,AP)的主动发射功率和IRS处的被动波束形成。仿真结果表明,基于IRS辅助的OFDM-IM系统与基准方案相比,其误符号率(symbol error rate,SER)或误码率(bit error rate,BER)可以降低60%~90%,在较高信噪比情况下,系统SER或BER可达到1.0×10^(-6),这说明IM和IRS技术的引入优化了端到端通信系统的链路传输质量。此外,以基于IRS辅助的OFDM-IM系统为标准,仿真结果证明了IRS模型和IM中各参数对系统的影响,并得出了系统中各模型参数要根据信道状态信息(channel state information,CSI)合理选择的结论。Index modulation(IM)and intelligent reflecting surface(IRS)are emerging mobile communication tech-nologies.In order to improve the reliability of traditional orthogonal frequency division multiplexing(OFDM)system,an orthogonal frequency division multiplexing with index modulation(OFDM-IM)system based on IRS-assisted was designed.Firstly,the OFDM-IM system was designed by using spatial modulation and frequency domain modulation to increase the Euclidean distance between subcarriers.Then,by establishing an equivalent circuit model,a practical IRS model was obtained.Finally,an alternating optimization algorithm was used to optimize the active transmission power of the access point(AP)and passive beamforming of the IRS jointly.The simulation results show that com-pared to the benchmark scheme,the symbol error rate(SER)or bit error rate(BER)of the OFDM-IM system based on IRS-assisted can be reduced by 60%~90%.Especially in the case of high signal-to-noise ratio,the SER or BER of the system can reach 1.0×10^(-6),which indicates that the introduction of IM and IRS technologies has optimized the link transmission quality of end-to-end communication system.In addition,based on the IRS-assisted OFDM-IM system as the standard,simulations are conducted to demonstrate the impact of various parameters from the IRS model and IM.It concludes that the parameters in the system should be selected reasonably according to channel state information(CSI).

关 键 词：智能反射面 索引调制 正交频分复用 相移模型 

分 类 号：TN929[电子电信—通信与信息系统]