The maximal rates and minimal decoding delay of more general complex orthogonal designs

AbstractSpace-time block codes based on complex orthogonal design have been widely investigated for their remarkable performance. In this paper, we propose a definition of more general complex orthogonal designs, which permits arbitrary complex factor with unit modulus in each entry. We prove that the maximal rate is still $$ \frac{{m + 1}} {{2m}} $$ for n = 2m or 2m − 1 antennas and minimal delay is also lower-bounded by $$ (_{m - 1}^{2m} ) $$. Thus, allowing complex factor with unit modulus in each entry will not improve the main performance criterion of space-time block codes.