In this letter, we present a new maximum likelihood (ML) decoding algorithm for space time block codes (STBCs) that employ multidimensional constellations. We start with a lattice representation for STBCs which transforms complex channel models into real matrix equations. Based on the lattice representation, we propose a new decoding algorithm for quasiorthogonal STBCs (QO-STBC) which allows simpleML decoding with performance identical to the conventional ML decoder. Multidimensional rotated constellations are constructed for the QO-STBCs to achieve full diversity. As a consequence, for quasi-orthogonal designs with an arbitrary number of transmit antennas N (N ≥ 4), the proposed decoding scheme achieves full rate and full diversity while reducing the decoding complexity from O(McN/2) to O(McN/4) in a Mc-QAM constellation.
Bibliographical noteFunding Information:
This work was supported in part by the Ministry of Knowledge Economy (MKE), Korea, under the Information Technology Research Center (ITRC) support program supervised by the Institute for Information Technology Advancement (IITA) (IITA-2008-C1090-0801-0013) and in part by grant No. R01-2006-000-11112-0 from the Basic Research Program of the Korea Science and Engineering Foundation. This paper was presented in part at the IEEE International Conference on Communications, Istanbul, Turkey, June 2006.
- Diversity methods
- Maximum likelihood decoding (MLD)
- Multidimensional rotated constellations
- Space-time block codes (STBC)
ASJC Scopus subject areas
- Electrical and Electronic Engineering