New Tight Upper-Bounds on the Error Probability of Multilevel Coded Modulation Schemes

This paper presents two theoretical upper-bounds on the word and bit error probabilities of individual levels of multilevel coded modulation schemes with equal error protection and multistage decoding. Lattice-type or PSK modulation with Ungerboeck partitioning over an AWGN channel is assumed. Inspired by both Imai's [1] and Wachsmann's [2] channel models, a new model is introduced, yielding the expression of two upperbounds tighter than those known so far [3][4]. The tightness of the bounds is illustrated with simulation results and compared to existing bounds. Finally, a method for approximating the simulated performance of individual levels is discussed.