Comparison of 16-ary DEQAM and 16-ary DEPSK signallings for spectrally efficient transmission over satellite links

A comparative study is presented of a 16-ary differentially encoded quadrature-amplitude-modulation (DEQAM) and 16-ary differentially encoded phase-shift keying (DEPSK) transmissions through a nonlinear satellite channel in the presence of additive white Gaussian noise (AWGN) and adjacent channel interference (ACI). It is assumed that the high-power amplifier of each earth station introduces both AM/AM and AM/PM conversion effects into the transmitted signals; the satellite transponder is assumed to be linear. The results show that in the presence of AWGN and ACI, 16-ary DEQAM systems outperform 16-ary DEPSK systems over nonlinear channels.link_to_subscribed_fulltex