Abstract
Space-time codes in both spatial and temporal domains have been proposed and become very popular for use in multi-input multi output systems. This thesis introduces a more general structure for super-orthogonal space-time codes called expanded super-orthogonal space time codes, which can retain the property that the maximum-likelihood decoding complexity is linear in the number of transmit antennas. Its codebook can be obtained by expanding the original space-time block code via both sides of unitary transformations. Besides, with a systematic parameterization, we can show a systematic procedure to obtain codebooks with optimal diversity gain. The results demonstrate better performance compared with super-orthogonal space-time block codes in terms of bit error rate.