In this paper, we introduce the optimal signal constellation design (OSCD) in both 2-D and multidimensional cases, which is obtained by minimization of mean square error of optimal source distribution.In addition, by analyzing block-interleaved coded modulation with iterative decoding, in which the bit error rate is Pregnancy Tests reduced by iteration of extrinsic information between a multilevel/multidimensional demapper and an LDPC decoder, with the help of EXIT chart, we propose new mapping methods for OSCDs outperforming previously known ones.The simulation results show that optimized mappings for LDPC-coded OSCDs outperform natural mappings by 0.
5 dB in 8-ary 2-D case and 0.6 dB in 16-ary 2-D case.Meanwhile, our proposed optimized mappings for 3-D-8-ary OSCD outperform natural mapping by 0.
2 dB and sphere packing constellation by 0.5 dB in coherent optical Rectangle - Acrylic Block LED Night Light OFDM few-mode fiber system.