High-Rate Complex Orthogonal Space-Time Block Codes for Multiple Transmit Antennas

Space-time coded modulation has been shown to efficiently use transmit diversity to increase spectral efficiency. Such high-rate orthogonal designs are available for complex symbol constellations only for two, three, and four transmit antennas. For five and six transmit antennas, two generalized complex orthogonal space-time block codes of rates 7/11 and 3/5 were proposed recently. In this correspondence, the complex orthogonal design for eight transmit antennas is presented. This code achieves the theoretically maximal rates and improved decoding complexity compared to known codes. Simulation results are provided to corroborate the analytical studies.