Multilevel Ternary Line Codes with Trellis

Abstract

In this paper, a combination of the two coding techniques given by Imai-Hirakawa and Pottie-Taylor is applied to the ternary (+,0,-) line code design problem. New ternary coding systems with reduced decoding complexities and improved error performance compared to those obtained by the classical Ungerboeck's trellis coding approach, are obtained. The decoding complexity for high coding rates are reduced by the proper choice of the punctured convolutional component codes for each partitioning level. A spectral null at zero frequency is obtained by the use of a 1/2 rate unit memory convolutional encoder at the last partitioning level which selects line codewords with opposite disparities in an alternated fashion so that the running digital sum values vary in a finite interval.