Sequential decoding of time-varying convolutional codes.

Abstract

A discussion of convolutional encoding and sequential decoding is given as background for the experimental phase of this research. A modified stack algorithm is programmed to simulate a sequential decoder for use in the study of time-varying convolutional codes. The decoder simulator is used to analyze the structure of codes with the aim of finding a systematic method by which to construct time-varying convolutional codes with good decoding properties. Some difficulties in construction techniques are discussed. Extensive computer simulation comparing decoding performance of time-varying codes to that of fixed codes Is reported. The conclusion of these comparisons is that the time-varying codes studied thus far are of theoretical interest only.