Nonlinear Trellis Description for Convolutionally Encoded Transmission   Over ISI-channels with Applications for CPM
  In this paper we propose a matched decoding scheme for convolutionally encoded transmission over intersymbol interference (ISI) channels and devise a nonlinear trellis description. As an application we show that for coded continuous phase modulation (CPM) using a non-coherent receiver the number of states of the super trellis can be significantly reduced by means of a matched non-linear trellis encoder. 
Fabian Schuh, Johannes B. Huber
cs.IT math.IT