Rate 5/6 Trellis-Coded 8-PSK

Abstract

Some new short constraint length codes are described for satellite channels which are constant-envelope and which have spectral and energy efficiencies intermediate to other recent coded techniques, namelyr = 2/3coded 8-PSK andr = 3/4coded 16-PSK. We use two intervals of 8-PSK transmission to form a modulation base forr = 5/6trellis codes. A particularly attractive design is an eight-state code, producing 6.2 dB gain on the Gaussian channel over uncoded 8-PSK, yet sacrificing only 16 percent in spectral efficiency.