基于旋转直积码本的3D有限反馈SDMA方案

Rotational kronecker-product codebook based 3-dimensional limited feedback SDMA

为平衡反馈开销和系统性能,在频分双工(FDD)系统下,针对三维多输入多输出(3D MIMO)系统的多用户预编码问题,提出一种应用于3D MIMO系统的基于统计信道信息的空分多址(SDMA)方法.首先,基于三维信道的空间相关性,提出3D MIMO中基于旋转直积的用户分簇码本设计,码本中每个分簇基的列向量相互正交,可作为发送方向用于下行预编码;其次,用户根据下行信道估计所得到的发端相关矩阵选取所在的分簇基及发送方向,并以长周期将其索引反馈至基站;最后,基站调度用户实现下行多用户传输.仿真结果表明:在信道相关性较高的情况下,该方法可以显著提升系统的吞吐量,且只须长时间向基站反馈信息,上行反馈开销极小.

Considering the multi-user precoding in frequency division duplex（FDD）three dimensional multiple-input multiple-output（3D MIMO）systems,a space division multiple access（SDMA）method was proposed based on statistical channel information that can be applied in 3D MIMO system to balance system performance with feedback overhead.Based on the spatial correlation of 3D MIMO channel,a user-clustering codebook was first designed as the kronecker product of rotated discrete Fourier transformation（DFT）matrices,in which column vectors are orthogonal and can be used as transmitting directions for precoding.Users selected the corresponding clustering basis and transmitting directions based on the transmit-side correlation matrix obtained by downlink channel estimation,then fed the selection information back to base station（BS）.Finally,BS transmited signal to the scheduled users.Simulation results demonstrate that the proposed SDMA method achieves high effectiveness with reduced feedback overhead when the channel correlation is high.