Receiver Constellation Waveform Subspace Preprocessing for Burst Alamouti Block STC CPM Modulation

The authors assume burst Alamouti coded STC CPM (MSK) modulation in MIMO channel as a particular example of nonlinear multichannel modulation (NMM). The NMM has multidimensional constellation waveforms. The major goal is to find suboptimal receiver signal preprocessing that could substantially reduce receiver decoding metric computation complexity with minor degradation of the STC performance. The author introduce linear waveform subspace projector reducing the dimensionality and thus the complexity of the receiver signal processing. The author analyzed the impact of the subspace projector on the code performance in terms of its rank, determinant (diversity and coding gain) and bit error rate. The author found an optimal subspace basis which does not reduce the rank of the code and which affects the determinant and bit error rate by the minimum possible amount.