In this letter, we propose a lattice-based full diversity design for rate-one quasi-orthogonal space time block codes (QSTBC) to obtain an improved diversity product for eight transmit antennas where the information bits are mapped into 4-D lattice points instead of the common modulation constellations. Particularly, the diversity product of the proposed code is directly determined by the minimum Euclidean distance of the used lattice and can be improved by using the lattice packing. We show analytically and by using simulation results that the proposed code achieves a larger diversity product than the rate-one QSTBCs reported previously.
Liu, W., Sellathurai, M., Wei, J., & Tang, C. (2010). A Cyclotomic Lattice Based Quasi-Orthogonal STBC for Eight Transmit Antennas. IEEE Signal Processing Letters, 17(4), 394-397. https://doi.org/10.1109/LSP.2009.2039951