New efficient method to generate optimal 2n-PSK space-time trellis codes with a large number of transmit antennas

In this study, the author propose a new method called coset partitioning to generate easily and efficiently the best space-time trellis codes (STTCs), thereby reducing considerably the usual important search time. This method, used in the case of 2ⁿ-PSK STTCs, is an extension of the set partitioning proposed by Ungerboeck based on the coset and lattice Calderbank´s approach. The main guideline of the coset partitioning is to divide the set of multiple input and output symbols into cosets, not into simple sets as the set partitioning. The case of a large number of transmit antennas is considered because the time to obtain the best STTCs with an exhaustive search is very important when the number of transmit antennas increases. Using the coset partitioning, new 4-PSK STTCs with five to six transmit antennas are generated. Simulation results show that the new codes slightly outperform the best corresponding known codes. Thanks to the effectiveness of the coset partitioning, for the first time, 4-PSK STTCs with seven and eight transmit antennas and 8-PSK STTCs with five to six transmit antennas are obtained. Their performance is also analysed by simulation.