Viterbi decoding of ternary line codes

The Viterbi decoding algorithm provides maximum likelihood decoding and has found widespread application since its introduction in 1967. It is currently the most widely used technique for the decoding of codes having a state system description, including the class of linear error correcting convolutional codes. Contrary to this, it is still common practice to use combinational logic decoders for ternary line codes. These are non-linear codes frequently used in metallic cable systems due to advantages such as efficient utilization of bandwidth, and a DC free power spectral density function. We investigate in this paper the behaviour of Viterbi decoding for the most important ternary line codes, and the coding gain that can be obtained by applying soft-decision decoding. The simplification of the Viterbi decoding implementation and the reduction in latency by shortening its survivor path length, have also been investigated.