Multiple-antenna wireless systems with space-time block-codes exploit channel-diversity for improving performance without loss in spectral efficiency. Up to date, most work on this area assumed that perfect channel estimates are available at the receiver so to make feasible fully coherent decoding. However, accurate channel-estimates require long training sequences that lower spectral efficiency. Therefore, in this contribution we focus on architecture, optimized design and performance of multiple-antenna block-coded systems with imperfect channel-estimates. After considering emerging fourth-generation WLANs (4GWLANs) as a possible application scenario, new performance bounds and optimized design criteria are presented together with a new family of robust-space block-codes that "self-match" to channel estimation errors.