基于二维嵌套阵的3D MIMO系统信道估计算法

信道估计通过对基站接收信号和用户端发送的已知导频序列进行处理获得。二维嵌套阵列可以节约系统的成本并且得到大规模MIMO（multiple-input multiple-output）天线阵列的性能，然而由于二维嵌套阵列的结构不规整，直接对基站接收信号进行处理具有一定的难度。本文提出一种基于2D-DFT（two-dimensional Discrete Fourier Transform）的信道重构算法，首先对接收信号做自相关处理转化为连续差分阵列的接收信号，然后通过2D-DFT估计出用户的每一条路径的初始DOA（the direction of arrival），然后利用角度旋转技术增强DOA估计实现超分辨率估计，再根据精确的DOA估计通过传统的LS（least squares）估计方法估计出信道增益；最后重构出用户的信道。数值仿真验证了算法的有效性。 

2D Nested Arrays Based Channel Estimation Algorithm for 3D MIMO Systems

Channel estimation is obtained by processing the received signal of the base station(BS) and the known pilot sequence sent by the user.Two-dimensional(2D) nested arrays save system cost and enable performance of massive MIMO(multiple-input multiple-output).However,the structure of 2D nested arrays is not a regular planar arrays,so it’s difficult to directly process received signal from BS.In this paper,a 2D-DFT-based channel reconstruction algorithm was proposed.Firstly,the received signal was autocorrelation processed and converted into received signal of the continuous differential co-array.Secondly 2D-DFT was used to estimate the initial direction of arrival(DOA),and the angle rotation technique was used to enhance the DOA estimation to achieve super-resolution estimation.Then channel gain was estimated by conventional LS estimation method based on accurate DOA estimation.Finally,user’ s channel was reconstructed.Various numerical results are provided to corroborate the proposed studies.