The maximal rates of more general complex orthogonal designs

The maximal rates and the minimal delays are basic problems of space-time block codes from complex orthogonal designs. Liang [5] systematically solved the problem on the maximal rates for a special kind of complex othogonal designs, and posed an open problem on the minimal delays. Recently, Kan & Shen [3] gave a negative answer for the open problem. In the paper, we prove that the maximal code rates that Liang gave in [5] also hold for more general complex orthogonal designs.