室内大规模天线系统无线信道空间相关性分析

Channel spatial correlation analysis for indoor large-scale antenna systems

无线信道空间相关性直接影响大规模天线系统的实际性能.基于大型报告厅内的无线信道测量数据,分析了基站天线阵列中不同阵元之间及不同用户之间的无线信道空间相关性.首先对阵元相关系数随阵元间隔的变化进行拟合建模分析,然后研究多用户信道相关性的影响因素.提出了一种负指数衰减余弦模型对其拟合建模.研究结果表明:在水平面内,阵元相关系数随阵元间隔增加近似为负指数衰减波动较小;在垂直面内,阵元相关系数随阵元间隔增加而呈现振荡衰减,基站天线数量增加对多用户信道相关性有明显改善,基站天线数量超过30以后,改善幅度变小但是仍有较明显提升.此外,不同用户之间的大尺度衰落会降低多用户信道正交性,且水平面内用户间大尺度衰落比垂直面内严重.但是基站阵列中不同阵元间的大尺度衰落对多用户信道正交性的影响十分微弱.

The performance of large scale antenna systems is affected by channel spatial ation. Based on field channel measurement in an auditorium, this paper analyzes the channel ation between different antenna elements in the array as well as different users. Antenna correlation coefficients with the antenna spacing are fitted with different models, and the factors that have impact on user channel correlation are also investigated. The results show that the an tenna correlation coefficients in the array decays exponentially with antenna spacing in the hori zontal plane. However, the antenna correlation tends to be a damped cosine wave in the vertical plane. In this paper, a model of negative exponential attenuation cosine is proposed to fit its rood eling.Increasing the number of antenna introduces significant decrease in user channel correlation, especially when the number of antennais less than 30. The large scale fading between different us ers degrades the channel orthogonality, and the fading is more severe in horizontal plane.Besides, the impact of large scale fading over the array on user orthogonality is limited.