Hybrid Multilevel SMTC/STTC Modulation for Fast Fading MIMO Channel

In this chapter, a new Hybrid Multilevel Modulation (HML) technique using Trellis based Spatial
Modulation (SM-TC) scheme and Space Time Trellis Coding (STTC) scheme as component code is
analyzed which exploits the advantage of both in an optimal way. In this method, antenna grouping
technique is used and the group is selected based on the Trellis based spatial modulation (SMTC)
(Basar et al 2011a). Using this technique, MIMO system can be designed with any number of transmit
antennas. The system is analyzed with optimal Viterbi decoding and suboptimal sequential decoding
algorithm and compared with equivalent MLSTTC and MLSM schemes. Further, the performance of
the HML system is analyzed with branch metric computation based on Maximum Likelihood (ML)
criteria and Multi Resolution Modulation (MRM) technique. The HML system using low complex
branch metric calculations based on the MRM scheme with sequential decoding gives improved
performance compared to equivalent MLSTTC over fast flat fading uncorrelated channel conditions
with 12.5% reduced computations.