Channel capacity achieving space-time block codes for MIMO systems with two, three and four transmit antennas

In this paper, three new multiple-input multiple-output (MIMO) channel capacity achieving, full and partial diversity, space-time block codes with reduced decoder complexities are proposed for MIMO systems having two, three and four transmit antennas. It is shown that the proposed codes have the same transmission rates as those of spatial multiplexing schemes while, moreover, offer second order transmit diversity. Computer simulations illustrate that the proposed code for two transmit antennas achieves the same performance as that of the best known code in the literature, the Golden code, with a lower decoding complexity while the proposed codes for three and four transmit antennas achieve better error performances than the corresponding spatial multiplexing schemes.