智能天线数字波束形成的LMS-DRMTCMA算法

本文提出一种适用于TD-SCDMA智能天线系统数字波束形成的LMS(最小均方)解扩重扩多目标恒模阵列(LMS-DRMTCMA)算法。该算法通过将Z.Rong等提出的LS解扩重扩多目标恒模阵列(LS-DRMTCMA)参考信号形成方法应用到LMS算法,并将TD-SCDMA标准提供的训练序列用于加速算法的收敛,使运算量远低于LS-DRMTCMA算法,明显低于导频LMS解扩重扩多目标阵列(LMS-DRMTA)算法。LMS-DRMTCMA算法还适用于激活用户数远大于天线阵元数的移动通信系统。仿真实验表明,LMS-DRMTCMA算法比LS-DRMTCMA算法和导频LMS-DRMTA算法具有更低的误码率,适合在极低信噪比环境中工作。LMS-DRMTCMA算法具有运算量低、易于实时实现的特点。

LMS-DRMTCMA Algorithm for Digital Beamforming of Smart Antenna

LMS-DRMTCMA (least mean square despread respread multi-target constant modulus array) digital beamforming (DBF) algorithm of smart antenna is proposed for TD-SCDMA systems. The reference signal used in LS-DRMTCMA (least squares despread respread multi-target constant modulus array) algorithm proposed by Z.Rong is applied to LMS algorithm. The training sequences, which are provided in TD-SCDMA standard, are also used in the LMS-DRMTCMA algorithm to accelerate convergence. LMS-DRMTCMA algorithm cuts down much computation complexity compared with LS-DRMTCMA algorithm. Furthermore, LMS-DRMTCMA algorithm is suitable for applying to mobile communications system in which the number of active users is far more than the number of array elements. The simulation experiments show that LMS-DRMTCMA algorithm can perform at much lower Bit Error Rate( BER) than pilot LMS-DRMTA and LS-DRMTCMA, and also can work in very low SNR situation. Therefore, LMS-DRMTCMA algorithm is characterized by low computation and easy real time implementation.