New results on space-time code design criteria

A sub-class of space-time codes, defined via compliance with a new criterion of optimality, is introduced. A new distance between two codewords is defined and leads to new criteria for code design. It is shown that, unlike the non-Euclidian metrics currently in use, the new distance measure is a true metric, its square has a useful additive property and, in itself, preserves the traditional form of the upper bound to the probability of mistaking two codewords, as encountered in the union bound. The resulting new criteria for space-time code design are presented