可重构智能表面中低复杂度毫米波信道估计算法

A Low Complexity Millimeter Wave Channel Estimation Algorithm in Reconfigurable Intelligent Surface

针对可重构智能表面(RIS)辅助的大规模多输入多输出(MIMO)毫米波系统中信道估计复杂度高的问题,该文提出一种低复杂度的信道估计算法。在该方案中,将RIS部分元素连接射频(RF)链,分离估计基站/用户和RIS之间的信道,分开获取信道有助于提升用户移动性场景下信道估计的灵活性。在所考虑系统中,首次使用低复杂度的2维快速傅里叶变换(2D-FFT)算法对角度进行估计,并考虑信号补零以获得更加精准的角度估计值,最后利用信号2维空间谱的谱峰和其对应的辐角得到路径增益估计。仿真结果表明,该算法达到了优良的信道估计性能,且在确保信道估计性能的系统参数设置下,该算法具有压倒性的复杂度优势。

In this paper,a low complexity channel estimation algorithm is proposed,which is used to reduce the computational complexity of the millimeter wave channel estimation in the massive MIMO systems assisted by the Reconfigurable Intelligent Surfaces(RIS).In the proposed scheme,some elements of the RIS are connected to the Radio Frequency(RF)chain to estimate the channel between the base station/user and the RIS separately,which improves the flexibility of channel estimation.The zero-padding two-Dimensional Fast Fourier Transform(2D-FFT)algorithm is used for angle estimation in this scenario for the first time.The path gain estimation is obtained by using the spectral peak of the two-dimensional spatial spectrum of the signal and its corresponding argument.Simulation results show that the proposed algorithm achieves excellent channel estimation performance,and based on the system parameter setting to ensure the channel estimation performance,the proposed algorithm has a strong complexity advantage.