Multi-Dimensional Space-Time Multilevel Codes
To date there has been little work done on multilevel codes for the space-time environment. In this paper we develop multi-dimensional space-time multilevel codes (ST-MLCs). Several construction methods are proposed, including a coset code approach. The proposed space-time multilevel encoders partition a 2Nt-dimensional signalling space, which spans all Nt transmit antennas. The multi-dimensional partitioning can be designed to reduce the complexity of detection/ decoding.We develop a spacetime multistage decoder for the proposed ST-MLCs. It allows the complexity of soft decision decoding to be significantly reduced compared to a single level approach. In addition, significant performance gains over a single level approach are obtained.