Performance of trellis codes for primary rate ISDN

Trellis code combines channel coding and modulation techniques for data transmission over band limited channels. Theoretically, it achieves significant coding gains over conventional uncoded multilevel modulation without compromising bandwidth efficiency. The authors study the effect of trellis encoding algorithms, and evaluate their effectiveness for the carrier serving area (CSA) loop environment in the presence of imperfect echo cancelers, for primary rate ISDN application. A basic methodology for the simulation of trellis codes for QAM clusters is utilized. The effect of trellis codes for 16and 64-QAM is studied. Results for the coded 16- and 64-QAM constellations for three typical loops with 60 dB of echo cancellations are presented. The effect of trellis codes on the entire PCSA (pseudo CSA) loop population is also presented.<
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