无线协作多点非理想回程下的CSI量化及分析

CSI Quantization and Analysis for Wireless Coordinated Multi-Point System Under Non-Ideal Backhaul Constraint

协作多点(CoMP)系统在第4代无线通信网络LTE-A及更远演化的版本中用于提高系统容量或分集,特别适用于蜂窝边缘.然而,在LTE-A CoMP系统中分布着非理想回程,非理想回程存在带宽限制和时延问题,使用户反馈到基站的信道状态信息(CSI)不完整,导致CoMP性能下降.针对该问题,文中提出了一种基于格莱斯曼流型理论的CSI量化方法,通过该方法对CSI进行量化及选择最优码书,以减小回程开销.数学分析和仿真结果说明,采用格莱斯曼流型法对CSI进行量化,非理想回程CoMP系统的性能可以得到改善.

Coordinated multi-point （CoMP） system has been applied to the 4th generation wireless communication network LTE-A and beyond networks to accommodate ever-growing need for system capacity and diversity. It is par- ticularly suitable for cell-edges. However, there exists bandwidth limit and transmission delay in the non-ideal backhauls of LTE-A CoMP system, which results in imperfect CSI （Channel State Information） feedback from user equipment to base stations and further causes the degradation of CoMP performance. In order to solve this problem, a CSI quantization method on the basis of Grassmann manifold theory is proposed. With this method, an optimal code book can be obtained to reduce the CS! feedback overhead. Both mathematical analysis and simulation show that the proposed method helps improve the CoMP performance under non-ideal backhaul constraint.