针对垂直维空间自由度未被充分利用的问题,设计一种基于部分Kronecker积的两级码本。在两级码本中,第1级码本确定一个波束向量组,该向量组确定用户的大致范围,描述信道的长期/宽带特性。第2级码本对此波束向量组进行波束列选择和极化方向间的相位调整,选出的波束能准确地指向用户,反映信道的短期/子带特性。该两级码本能平衡大规模MIMO系统中反馈开销和信道量化精确度之间的关系。仿真结果表明,在不增加反馈开销的情况下,该码本设计方法在系统频谱效率和吞吐量方面能获得明显的性能增益。
Aiming at the problem that the additional degrees of freedom in the vertical dimension cannot be fully utilized,a.partial Kronecker product based dual-stage codebook is proposed.In the dual-stage codebook,the first stage determines a beam group and identifies the approximate range of the user and describes the long-term/wideband properties of the channel.The second stage performs column selection from the beam group and quantizes the co-phasing between two polarizations.Accordingly,the selected beam improves the beam-steering accuracy of the user,the shortterm/subband information of channel may be tracked by the second stage.The dual-stage codebook can make a good tradeoff between the feedback overhead and the accuracy of channel quantization in the massive Multiple-input Multipleoutput(MIMO) systems.Simulation results show that the proposed codebook scheme achieves significant performance gain in terms of the whole spectral efficiency and throughput.