Eigenmode SNR increasing method for ML criterion based space-time linear precoder

In this paper, we propose an eigenmode SNR increasing method for a maximum likelihood (ML) criterion based space-time linear precoder (ML-STLP). In the proposed method, several ML-STLPs are employed for one frame whereas only one ML-STLP is employed in the conventional method. When over two ML-STLPs are employed, the same ML-STLPs, which have short preceded symbol length, are arranged in parallel. Also, a length of preceded symbol for one frame and a data rate are same between the proposed method and the conventional method. We investigate the effect of the preceded symbol length on the resulting eigenmode SNR and show that the eigenmode SNR increasing can be achieved by selecting the preceded symbol length with higher eigenmode SNR depending on the channel condition. Also, the applicability of the proposed method is demonstrated by a computer simulation