Improved high-rate space-time codes via concatenation of expanded orthogonal block code and M-TCM

In this paper, we propose a new technique for designing an improved high-rate space-time code. The proposed code construction is based on a typical concatenation of a space-time block code and an outer TCM/MTCM encoder. However, unlike the existing STB-MTCM schemes which are rate-lossy, the proposed technique produces higher-rate space-time codes by expanding the cardinality of the available orthogonal space-time signal points before concatenating with an outer M-TCM encoder. The set partitioning concept is then employed to realize large coding gains. Here, we present design examples for the 2-transmitter and 3-transmitter cases. The new space-time codes considerably outperform the existing designs. Furthermore, signal orthogonality is exploited to keep decoding complexity of the proposed construction relatively low