Channel Extrapolation Techniques for E-SDM System in Time-Varying Fading Environments
Channel Extrapolation Techniques for E-SDM System in Time-Varying Fading Environments
复制标题
时变衰落环境中 E-SDM 系统的信道外推技术
DOI：
10.1093/ietcom/e89-b.11.3083
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
T. Nishimura
中科院分区：
文献类型：
--
作者：
H. Bui;Y. Ogawa;T. Ohgane;T. Nishimura
与使用传统空分复用 (SDM) 的系统相比，使用特征波束空分复用 (E-SDM) 的多输入多输出 (MIMO) 系统性能良好，并且容量有所增加。然而，发射机处需要信道状态信息(CSI)，并且E-SDM系统的性能很大程度上取决于发射机和接收机处的CSI的准确性。在时变衰落环境中，传输权重确定时间和实际数据传输时间之间的信道变化会导致系统性能下降。为了补偿信道误差，已经提出了用于时分双工系统的线性外推方法。不幸的是，随着最大多普勒频率的增加，系统性能仍然恶化。这里，提出了两种信道外推新技术。一种是二阶外推，另一种是指数外推。此外，我们提出了指数外推的最大多普勒频率估计方法。 4tx 4rx MIMO 系统的仿真结果表明，使用所提出的技术，E-SDM 系统在较高的多普勒频率区域表现更好。
Multiple-input multiple-output (MIMO) systems using eigenbeam space division multiplexing (E-SDM) perform well and have increased capacities compared with those using conventional space division multiplexing (SDM). However, channel state information (CSI) is required at a transmitter, and the performance of E-SDM systems depends much on the accuracy of the CSI at a transmitter and a receiver. In time-varying fading environments, the channel change between the transmit weight determination time and the actual data transmission time causes the system performance to degrade. To compensate for the channel error, a linear extrapolation method has been proposed for a time division duplexing system. Unfortunately, the system performance still deteriorates as the maximum Doppler frequency increases. Here, two new techniques of channel extrapolation are proposed. One is second order extrapolation, and the other is exponential extrapolation. Also, we propose maximum Doppler frequency estimation methods for exponential extrapolation. Simulation results for 4tx 4rx MIMO systems showed that using the proposed techniques, E-SDM system performs better in a higher Doppler frequency region.