基于导频序列的空时编码OFDM系统的信道估计方法

利用空时分组码(STBC)导频序列,在最小二乘(LS)和最小均方误差(MMSE)信道估计技术的基础上,用基于本征向量分解(EVD)的低秩信道估计技术对空时编码OFDM系统进行信道估计,避免了矩阵求逆运算,大大减少了运算量。分析并仿真了在降低秩条件下的系统性能和用不同调制结构的不同空时码的性能。仿真结果表明,降低秩会影响系统性能,当忽略掉一个相对较小的特征值时,系统性能降低较少;如果相对很重要的特征值被忽略,系统性能就会随信噪比的增大下降较多。系统性能会随空时码状态的提高和采用更高调制结构而提高。

Method of channel estimation based on pilot sequence for space-time coded OFDM system

Based on Least Square(LS) and Minimum Mean Square Error(MMSE) channel estimation techniques,in this paper,the channel estimation techniques using Space-time Block Codes(STBC) pilot sequences are introduced.A low rank channel estimation techniques based on Eigen Vector Decomposition(EVD) is investigated,so it avoids the large scale matrix inversion and thereby reduces the complexity significantly.The performance under the reduced rank and the performance of different modulation schemes and different space time codes are analyzed and simulation.The results show that the performance will be effect if it reduced rank,when the ignored eigen value is comparatively small,the performance will not degradation much;while when the significant value is ignored,the degradation of performance increases with SNR.And performance will be improved with higher state Space Time Codes or with higher modulation schemes.