摘要
大规模多入多出(Massive MIMO)系统中,随着天线数的增加,线性预编码算法的性能逐渐趋于最优,选择合适的线性预编码对系统性能具有重要的意义。针对发射端信道状态信息(Channel State Information at Transmitter,CSIT)不完美的Massive MIMO系统,推导出了迫零(Zero-Forcing,ZF)和最大比传输(Maximum Ratio Transmission,MRT)这两种常见预编码方案在向量归一化方式下的下行可达和速率下界,并给出了证明。随后对两种下界进行了分析,提出了一个关于系统用户数的阈值,当系统用户数和阈值的大小关系不同时,两种预编码性能的优劣关系也不相同。根据分析结果,文章进一步提出了一种以系统中用户数为参量的预编码选择策略,可以保证不论用户数如何变化,系统都能选择出更优的那一个预编码算法来对信号进行预处理。分析的有效性和方案的可靠性通过仿真得到了验证。
In massive MIMO （Muhi-Input Multi-Output） system, linear precoding＇ s performance tend to be optimal while the number of the antennas increased. Hence, choosing a appropriate linear precoding has a significant meaning to the performance of system. For this paper, the downlink achievable sum rate of Zero-Forcing （ZF） precoding is analyzed and Maximum Ratio Transmission （MRT） precoding use vector normalization in massive MIMO system with imperfect CSIT then give proof. Compare the pe formances of these two precodings and a threshold is proposed on the number of users in the system, when the number of users different from the system threshold, the merits of two pre-coding performance also different. According to the results , a procedure of precoding schemes selection is provided which is depend on the number of system users. This procedure choose the better precoding algorithm no matter the amount of users change. The computer simulation proves the method is correct.
出处
《电视技术》
北大核心
2016年第5期40-47,共8页
Video Engineering
基金
国家科技重大专项项目(2014ZX03003005-003)
陕西省国际科技合作与交流计划项目(2015KW-012)
