八天线TD-LTE系统的波束赋形算法分析

多天线是天线技术的发展趋势,TD-LTE引入了8发2收的天线配置.基于小间距多天线阵列,利用TDD系统信道互易性,波束赋形技术可以根据上行导频获得信道信息,形成对基带(中频)信号的最佳组合或者分配,补偿无线传播过程中由空间损耗、多径效应等因素引入的信号衰落与失真,同时降低同信道用户间的干扰.EBB(Eigen-based Beamforming)算法是波束赋形主要算法之一,该算法中在整个波束空间中,找到使接收信号功率最大的赋形权矢量.通过仿真,对EBB算法在各种应用场景下的性能进行了分析,结果表明八天线EBB波束赋形算法可以正确实现波束合成,在低速或上行信道信息估计误差较小情况下能够明显提高系统性能.

8 Antennas Eigen-based Single Stream Beamforming Algorithm for TD-LTE System

Multi antenna technology is the mobile telecommunication trend and an 8×2 antenna configuration is introduced in TD LTE recently. Based on small distanc e multi antenna arrays, in such a system, by utilizing the TDD system specific ch annel reciprocity characteristic, the beamforming gets channel information form uplink signals, then forms the best combination or distribution of base-band (IF ) signal, compensates signals fading and distortion caused by facto rs such as space loss or multi path effects in wireless communication process, w hile reducing co channel interference between users. EBB (Eigen based Beamform in g) algorithm is one of the main algorithms for beamforming. EBB algorithm finds the weight vector in the whole beam space, which makes the receiving signal powe r biggest. Through simulation, the EBB algorithm performance under various appli cation scenarios is analysed. The results show that the 8 antennas EBB algorithm can correctly achieve beam synthesis and significantly improve the system g ain under the cases with low speed and small channel estimation error.