RIS辅助高铁毫米波通信的信道估计算法

Channel Estimation Algorithm for RIS-Assisted High-Speed Railway Millimeter-Wave Communication

为了解决高铁毫米波无线通信信道估计导频成本过高等问题,提出一种利用可重构智能表面(RIS)辅助的毫米波通信系统信道估计方案。在该方案中,首先利用卡尔曼滤波器(KF)对信道进行预测,基于高铁毫米波信道前后时刻的相关性得到信道状态信息(CSI)的估计值;其次,基于正交匹配追踪(OMP)算法对高铁毫米波稀疏信道进行恢复,得到RIS的最佳反射矩阵;最后在数据传输阶段,根据最佳反射矩阵调整RIS的幅度和相位来控制无线传输环境,从而提升高铁毫米波无线通信信道的传输性能。仿真结果表明,与传统的最小二乘(LS)算法、最小均方误差(MMSE)算法、OMP算法相比,KF-OMP算法在时变信道中表现出更优越的性能。

To solve the problem of high pilot cost in high-speed railway millimeter-wave wireless communication channel estimation,this study proposes a channel estimation scheme for millimeter-wave communication systems assisted by a reconfigurable intelligent surface(RIS).In this scheme,a Kalman filter(KF)is used to predict the channel,and the estimated channel state information(CSI)is obtained based on the correlation between adjacent time slots of the high-speed railway millimeter-wave channel.Then,an orthogonal matching pursuit(OMP)algorithm is used to recover the highspeed railway millimeter-wave sparse channel to obtain the optimal reflection matrix of the RIS.Finally,in the data transmission stage,the amplitude and phase of the RIS are adjusted according to the optimal reflection matrix to control the wireless transmission environment,thereby improving the transmission performance of the high-speed railway millimeter-wave wireless communication channel.Simulation results show that,compared with the traditional least squares(LS),minimum mean square error(MMSE),and OMP algorithms,the KF-OMP algorithm exhibits superior performance in time-varying channels.