Phase jitter sensitivity of rotationally invariant 8 and 16-point trellis codes

The authors describe the rules and the procedures used in designing feedforward rotationally invariant trellis codes. Eight PSK (phase shift keying), 16 PSK and 16 QAM (quadrature amplitude modulation) trellis codes with and without rotational invariance are discussed, and their performances under different degrees of phase jitter are compared. It is found through computer simulation that for practical values of root-mean-square phase jitter, coding gains for rotationally invariant codes are either maintained or enhanced through trellis coding