Real-Time Application of Trellis Coding to High-Speed Voiceband Data Transmission

We describe the application of multilevel trellis coding to the transmission of high-speed´ voiceband data. The implementation aspects of soft-decision Viterbi decoding associated with such coding are discussed, Real-time performance comparison is made of two coded systems at 9600 bits/s with respect to an uncoded system. The performance sensitivity Of the three systems to DDD channel impairments other than additive Gaussian noise are also described. It is shown that the experimental results agree well with those from theory, and that trellis coding provides significant improvement in performance in the presence of impairments other than additive Gaussian noise.