Construction of Efficient Amplitude Phase Shift Keying Constellations

Inhalt:
Well-known modulation schemes for additive white Gaussian noise (AWGN) channels are based on uniform input distributions. Thus, their number of constellation points normally is a power of two. In this work, a method for the construction of efficient amplitude phase shift keying (APSK) modulation schemes is presented. The number of constellation points are not restricted to powers of two, and the referring input distributions are not uniform, although dyadic. Compared to the well-known quadrature amplitude modulation (QAM) schemes, they provide shaping gain both by arranging the constellation points in a circle, and due to the usage of non-uniform input distributions. Additionally, they allow a finer adaptation to the channel state. Performance evaluations show that these schemes are often better than the QAM schemes.