We present a new architecture of layered space-time codes as a combination of BLAST architecture and of special STTC codes which are variations about the codes first introduced by Jafarkhani et al. and named Super Orthogonal Space-Time Trellis Codes (SOSTTC). Using powerful set partitioning, these codes are able to combine the coding advantage of STTC’s together with the advantage diversity of orthogonal Space-Time Block Codes (STBC). The system we propose is named Super Quasi Orthogonal Horizontal Layered Space Time Trellis Code (SQOHLSTTC). It consists in a powerful STBC based STTC originally derived for a three transmit antenna system, together with an original block based decoding algorithm which enables to use a higher number of transmit antennas. The decoding of SQOHLSTTC combines group interference suppression and group interference cancellation techniques. To implement the system, we propose a low complexity hard decision iterative decoding method. System performances are illustrated and confirm the great interest of the proposed transmission scheme.