ML Decoding Complexity Reduction in STBCs Using Time-Orthogonal Pulse   Shaping
  Motivated by the recent developments in the Space Shift Keying (SSK) and Spatial Modulation (SM) systems which employ Time-Orthogonal Pulse Shaping (TOPS) filters to achieve transmit diversity gains, we propose TOPS for Space-Time Block Codes (STBC). We show that any STBC whose set of weight matrices partitions into P subsets under the equivalence relation termed as Common Support Relation can be made P -group decodable by properly employing TOPS waveforms across space and time. Furthermore, by considering some of the well known STBCs in the literature we show that the order of their Maximum Likelihood decoding complexity can be greatly reduced by the application of TOPS. 
Rakshith Rajashekar and K. V. S. Hari
cs.IT math.IT