  In this paper, we introduce further our recently designed family of L2
orthogonal Space-Time codes for CPM. With their advantage of maintaining both
the constant envelope properties of CPM, the diversity of Space-Time codes and
moreover orthogonality, and thus reduced decoding complexity, these codes are
also full rate, even for more than two transmitting antennas. The issue of
power efficiency for these codes is first dealt with by proving that the
inherent increase in bandwidth in these systems is quite moderate. It is then
detailed how the initial state of the code influences the coding gain and has
to be optimized. For the two and three antennas case, we determine the optimal
values by computer simulations and show how the coding gain and therewith the
bit error performance are significantly improved by this optimization.
