Abstract
In this thesis, the design of LDPC coded modulation is considered, where conventional density evolution and importance sampling cannot be used. Since non-zero codeword cannot be used for asymmetric channel, we introduce a method to modify importance sampling. In addition, EXIT (extrinsic information transfer) chart can't be applied to quantized PAM (pulse-amplitude modulation) since the Gaussian approximation for the soft values may loss its accuracy. Therefore, density evolution is modified for LDPC coded modulation. Although the use of gray labelling can achieve low threshold, the error floor performance can be enhanced using the proposed labelling. The proposed labelling is searched for LDPC coded modulation, where the labelling criterion is considered to lower error floor. These techniques are applied to LDPC coded MLC flash memory systems which is an LDPC coded modulation.