On bounding the coding gains of space-time coset codes

Many space-time codes can be viewed as coset codes. This new perspective not only confirms the relevance of Euclidean distance and geometrical properties to space-time coding, but also helps to shed light on the structures, geometrical properties, and performances of space-time codes. From this new perspective, some geometrical properties, such as the geometrical uniformity of space-time codes, are easily seen. Using this new viewpoint, we directly relate the space-time coding gain to the fundamental coset coding gain of the same collection of signal point sequences by giving a bound on coding gains of the space-time codes over a flat quasi-static fading channel if and when they are viewed as coset codes