Soft decision decoding for multilevel coding with different mapping strategies in presence of fading

This paper focuses on the influence of soft derision decoding on multilevel coding (MLC) schemes with different mapping strategies, named UP (Ungerboeck's (1982) partitioning), BP (block partitioning) and MP (mixed partitioning), in Rayleigh fading channels. Based on the capacity rule, 8ASK MLC systems are constructed using punctured convolution codes. The performance comparisons are made for soft and hard decision decoding by using soft decision decoding for selected coding levels. The error propagation resulted from the lower level is also discussed. The results can present some references for the optimal criterion for MLC design in fading channels.