RIS辅助毫米波MIMO级联信道的角度估计

智能反射表面（RIS）用低成本的无源反射元件控制入射信号的相位，将增强第6代移动通信系统的无线覆盖范围，并提高信道容量.由于RIS辅助毫米波多入多出（MIMO）级联信道仅有少量的弥散空间角度和相应的路径损耗，提出采用无网格的原子范数最小化方法来估计下行链路基站处的离开角和用户处的到达角，把级联信道的角度估计问题转化为凸优化模型进行求解.仿真结果表明，仅用少量的快拍数就能得到精确的角度参数.

Angle estimation for RIS assisted millimeter wave MIMO cascaded channels

The intelligent reflective surface (RIS) used low-cost passive reflective elements to control the phase of incident signal, which could enhance wireless coverage range and improve channel capacity in the sixth-generation mobile communication system. Since the dispersion environment of the RIS-assisted millimeter wave multiple input multiple output (MIMO) cascaded channel only had a few paths with corresponding spatial angles and loss, the non-grid atomic norm minimization method was proposed to estimate the angle of departure at base station and the angle of arrival at user equipment on downlink in this paper. The angle estimation problem was converted into convex optimization models for solution. Simulation results showed that accurate angles could be obtained only with a small number of snapshots.