Structured trellis encoding
G. Zou, H. Weinrichter · IEE Proceedings I Communications Speech and Vision · 1990
We propose a systematic trellis encoding technique based on trellis partitioning and on newly defined branch distances. This encoding technique avoids the usual exhaustive search for finding good trellis codes. It gives the lower and upper bounds on free distance which depend only on the encoder memory and the signal space. We also discuss the optimal combination of signal set and trellis and give the sufficient condition for avoiding catastrophic codes.