Differential Unitary Space-Time Modulation Based on Rotation Matrix

The performance of traditional differential unitary space-time coding is still imperfect in high signal-to-noise ratio (larger than 10 dB). A new design method of differential unitary space-time constellation is introduced. This method is based on rotation matrix. The non-group constellation designed by the proposed method will have a larger diversity product than the constellation designed by conventional cyclic group code. So it will have a better performance in theory. This proposed method could also be reduced to lesser computational complexity. When the size of the constellation is even, the number of the optimized parameter can be reduced to 3. The simulation results show that the performance of the proposed code is about 1 dB better than cyclic unitary code at BER(Bit Error Rate) is 10~(-4).