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 2N_t-dimensional signalling space, which spans all N_t transmit antennas. The multi-dimensional partitioning can be designed to reduce the complexity of detection/decoding. We develop a space-time 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