Application of Shaping Technique to Multi-level Turbo-Coded Modulation

This article presents a method for the combined Turbo-code and QAM modulation using coset coding. A symbolbased Turbo-code acting on symbols of size 4 is used to select a coset along each one-D sub-constellation (using the partition Z=4Z). The proposed method satisfies the conditions for the separability of shaping and coding, and consequently, can be easily integrated with a shaping algorithm. Numerical results are presented which show that the proposed configuration outperforms the best known techniques in terms of the complexity and BER performance. The proposed method also demonstrates an excellent performance near the error floor region