一种新的MIMO OFDM系统特征模式构造方法

Novel Eignmode Construction Method for MIMO OFDM Systems

特征模式分解是MIMO OFDM系统进行自适应功率分配的前提,而目前MIMO OFDM系统的模式大多是通过每个载波信道矩阵的奇异值分解得到。但是,这种分解方法在载波个数很多时,具有很大的实现复杂性,且脱离空时编码在MIMO OFDM下的实现形式,使最终的功率分配结果忽视了空时编码对系统性能的影响。为此,通过空时编码MIMO OFDM系统模型,给出一种全新的特征模式分解方法。该方法综合了空时编码的实现,不必针对每个载波进行特征模式分解,具有更简单的实现形式。实验结果进一步表明,与传统的特征模式分解相比,新特征模式分解具有更好的鲁棒性。

In current MIMO OFDM systems, the eignmode decomposition of spatial channel is the preconditions of adaptive power allocations, and these eignmodes are generally obtained by the singular value decompositions of the channel matrix at every carrier. However, the decomposition in this way doesn＇ t consider the special implementation in MIMO OFDM systems, which ignored the effects of space time codes on system performance. Furthermore, it has great complexity for the case with a larger number of carriers. So, a novel eignmode decomposition is proposed to integrate the space time codes in system models, which could be conducted simultaneously for many carriers with simple implementation. Numerical results show that the novel eignmode decomposition is more robust than the classical approaches.