Further reduced search for optimal diagonal space-time constellations from groups

A reduced search algorithm for optimal diagonal space-time constellation is introduced. This algorithm reduces the computations by using the symmetrical attribute of the determinant distances, and by grouping the search space as a union of some equivalent classes. In an equivalent class, all of its elements will generate the same constellation set, in which there is exact one needed to be searched. As a result, the search are significantly reduced since no any repeatedly search is performed.