Design of Space-Time Trellis Codes for Transmit-Correlated Fading Channels

We derive design criteria for space-time trellis codes in the presence of transmit correlation. For the case of two transmit antennas we show that in strongly correlated channels, performance is governed by the constellation that results from the sum of the constellations associated to the transmit antennas. This suggests the use of new constellations to design better codes for correlated channels. The design criteria are then extended to any number of transmit antennas. Based on these criteria, we derive new space-time Trellis codes for two and three transmit antennas that perform much better in correlated channels than STTC optimized for the i.i.d. case