大尺度衰落LTE协作通信的波束成型优化设计

Beamforming optimization for LTE cooperative transmission with large-scale fading

大尺度衰落环境不仅具有较长的信道延时特征,而且具有明显大于LTE调制带宽的系统交换延迟。当基于相邻小区基站进行虚拟天线联合处理,并对多个接收簇进行组播协作通信时,必须考虑两类延时带来的延时误差。此时,每个接收簇由多个单天线接收节点构成,簇内节点接收相同的信息流,不同簇间信息流不同。文中研究了发射天线之间存在交换同步延迟的情况下的信道估计性能,评估了系统整体性能,并在此基础上提出了一种波束成型的优化设计方案。仿真及部分算法分析表明,新算法可通过对每个接收节点的信号与干扰加噪声比(SINR)进行优化来提升整体系统性能,可在实际大尺度LTE工作环境下获得更好的系统性能。

large-scale fading environment not only has the character of channel delay, but its system switching delay is much larger than the modulation bandwidth of LTE. Such two kinds of delay have to be taken into account when the base stations in contiguous cells are going to form virtual antenna array for joint process and make cooperative transmission to multiple receiving clusters. Each cluster is supposed to receive a distinct data stream while nodes in each cluster receive the same packet simultaneously. This paper analyzes the performance of channel estimation and overall system performance with the existence of synchronization error among different transmitting antennas. A beamforming optimization is also given based on result of channel estimation. Using the simulation, it proves that through the optimization on each node＇s signal to noise and interference ratio （SINR）, the new scheme can greatly enhance the overall system performance in the practical large-scale LTE environment compared with other approaches.