The DS/SSMA systems using trellis coding with asymmetric PSK signal constellation

Analyzes the performance of direct-sequence spread spectrum multiple access (DS/SSMA) systems using trellis coding with asymmetric phase shift keying (PSK) modulation. By designing the signal constellation to be asymmetric, the authors obtain a performance gain of DS/SSMA systems over the systems using the traditional symmetric signal constellation. Bit error probability analysis of the proposed system is carried out for some cases. A few examples are given to show the performance gain due to the asymmetry of the signal constellation.