Two generalized complex orthogonal space-time block codes of rates 7/11 and 3/5 for 5 and 6 transmit antennas

Space-time block codes from orthogonal designs have two advantages, namely, fast maximum-likelihood (ML) decoding and full diversity. Rate 1 real (pulse amplitude modulation-PAM) space-time codes (real orthogonal designs) for multiple transmit antennas have been constructed from the real Hurwitz-Radon families, which also provides the rate 1/2 complex (quadrature amplitude modulation-QAM) space-time codes (complex orthogonal designs) for any number of transmit antennas. Rate 3/4 complex orthogonal designs (spacetime codes) for three and four transmit antennas have existed in the literature but no high rate (>1/2) complex orthogonal designs for other numbers of transmit antennas exist. We present rate 7/11 and rate 3/5 generalized complex orthogonal designs for five and six transmit antennas, respectively.