Abstract

1 Introduction Power and bandwidth efficient digital communication 1 The recently proposed Turbo codes are applied to bandwidth efficient modulation schemes via multilevel coding. For this purpose, Turbo codes are extended for a wide range of fine tunable rates by puncturing. A straightforward derivation of iterative Turbo decoding and the concept of extrinsic information is presented. New design rules for multilevel codes with arbitrary component codes and codeword lengths are derived from information theory. Simulation results show that application of Turbo codes to properly designed multilevel coding schemes leads to digital transmission schemes with high power and bandwidth efficiency. Since C.E. Shannon's fundamental work [1] the task in channel coding theory has been to find digital communication schemes with tolerable complexity close to the capacity limit. For a long time, mainly binary codes have been the focus of interest. Recently, a coding scheme with rate 1 2, consisting ...

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