Space-time multilevel coded modulation with iterative detection for multiple-antenna transmission

We propose a novel space-time coded modulation approach for multi-antenna systems, namely space-time multilevel coded modulation with iterative decoding (ST-MLCM-ID), for the purpose of exploiting both multiplexing gain and multilevel coding gain. This scheme allows flexible selection of space-time mappings, signal constellations, and outer codes used on each level of the mapping, for each antenna. We introduce the concept of the space-time distorted bit-level extrinsic information transfer (STDBL-EXIT) function, derive the area properties of the STDBL-EXIT functions in information theoretic terms, and show a highly-efficient code design rule for ST-MLCM-ID. Simulations further demonstrate that by employing our rule based on the STDBL-EXIT function, ST-MLCM-ID is capable of achieving full convergence close to the theoretical limit, while also allowing sufficient flexibility in the choice of codes on each level of the space-time mapping of each antenna.