多载波码分多址系统的上行空频信道盲估计

把均匀线阵应用于宏蜂窝制同步多载波码分多址系统的基站，给出了相应的空频信道模型，并构造了蕴涵空频信道信息和波达方向信息的辅助矩阵，利用子空间方法对辅助矩阵进行特征分解，实现了对同步多载波码分多址系统上行空频信道和波达方向联合盲估计，与借助旋转不变技术估计信号参数类方法不同，该方法巧妙回避了多个矩阵的联合对角化问题，基于对小区内各活动用户上行空频信道的估计，进一步实现了空频联合多用户符号检测，仿真结果表明，与基站仅使用单天线的同步多载波码分多址系统相比，该方法能够更好地减轻多用户情形下的多址干扰。

Blind Uplink Space-Frequency Channel Estimation for Multi carrier Code Division Multiple Access Systems

The uniform linear array (ULA) is investigated at the base station of macrocell synchronous multicarrier code division multiple access (MC CDMA) systems in a frequency selective fading channel environment.The resultant space frequency channel model is described. In order to resolve the joint estimation problem of both uplink space frequency channel and direction of arrival (DOA) blindly, an auxiliary matrix including uplink space frequency channel and DOA information is constructed. Based on subspace methods, by performing eigen decomposition on this auxiliary matrix, the closed form solution of both space frequency channel and DOA can be obtained simultaneously for all active users within one macrocell.By contrast with schemes like estimation of signal parameters via rotational invariance techniques (ESPRIT),the proposed scheme can elegantly avoid the joint diagonalization problem of multiple matrices. The estimated uplink space frequency channel can further be used for individual active user to implement the joint space frequency multiuser symbols detection. Simulation results demonstrate that the novel scheme can well mitigate the multiple access interference in multi user scenarios superior to the synchronous MC CDMA system with a single antenna at base station.