Abstract: The complex orthogonal designs with maximal rates and minimal delays is an open problem for space-time block codes. Maximal rates can effectively transmit symbols to the lonest distance in the space dimension ; and minimal delays is the least decoding delays in the time dimension. Many authors have observed that regarding the complex orthogonal designs for space-time block codes with the antennas n = 4k (k N), its minimal delay is the same as that for n=4k-1. However none was able to prove it.In this paper, we use the characteristics of Hadamard matrix to prove this property to fulfill this vacancy. 16 Refs. In English.

Key words: Complex orthogonal space-time block codes; Hadamard matrix; minimal delays; maximal rates