Combined Multiple Transmit Antennas and Multi-Level Modulation Techniques
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Orthogonal transmit diversity with optimum signal combining can take full advantage of fading multi-path channels. Such a scheme however, has a bandwidth efficiency which decreases proportionally with the number of transmit branches, hence making it less attractive for wireless communication systems. It was recently shown that by using different constellation mapping for each transmit branch, improved performance can be obtained for an orthogonal transmit diversity system. It was shown that optimized constellations provide good spread for the constellation signal points and can be quite efficient for high-level linear modulation techniques. This thesis considers the extension of constellation rearrangement scheme to multiple transmit antennas as opposed to orthogonal transmit branches. Constellation rearrangement is used in conjunction with conventional space-time block coding schemes. While keeping the same rate and complexity, the obtained results show improvement over the system employing orthogonal transmit diversity with constellation rearrangement. Analytic upper bounds, to evaluate the performance of the new modified space-time block coding scheme, are also derived. Application of trellis-coded modulation in conjunction with the new scheme is also considered. This can be seen as, concatenation of trellis coded modulation with combined constellation rearrangement and space-time block coding. The obtained simulation results indicate further performance improvements for the concatenated scheme.
Place, publisher, year, edition, pages
2005. , 52 p.
Trita-S3-RST, ISSN 1400-9137 ; 0510
Computer and Information Science
IdentifiersURN: urn:nbn:se:kth:diva-28545OAI: oai:DiVA.org:kth-28545DiVA: diva2:387965
Slimane, S. Ben