On high-rate full-diversity 2 × 2 space-time codes with low-complexity optimum detection
IEEE Transactions on Communications
Blind channel estimation in orthogonally coded MIMO-OFDM systems: a semidefinite relaxation approach
IEEE Transactions on Signal Processing
IEEE Transactions on Wireless Communications
Hi-index | 754.84 |
In this correspondence, we prove an interesting property of orthogonal space-time block codes (OSTBCs). For flat block-fading channels, it is shown that the internal structure of the vector space of the input constellation remains invariant to the effects of both the OSTBC and the channel except for certain scaling factors. This property sheds light on the mechanism of maximum-likelihood (ML) decoding of OSTBCs and, in particular, provides an alternative explanation of why optimal decoding can be reduced to symbol-by-symbol decoding. New simple expressions for the ML decoder are obtained which clarify its intrinsic structure.