Expanded QAM mapping predistorter for nonlinear SSD-QPSK

Signal-space diversity (SSD) has received a lot of attention for use in broadcasting due to its robustness in harsh channel environment. However, SSD converts constant envelope QPSK signal into multiple level QAM-like signal. In the previous researches on SSD applied systems, nonlinear amplification effects have not been considered. In this paper, an expanded QAM mapping predistorter is proposed for use with SSD transmitter in order to compensate for HPA nonlinearity. BER performance is simulated to demonstrate the performance improvement of the proposed scheme.