LDPC-coded BICM-ID based nonuniform signaling for ultra-high-speed optical transport

An LDPC-coded BICM-ID scheme with nonuniform signaling (NS) for 9-QAM and 12-QAM is proposed, which is designed by mapping Huffman code onto constellations. We demonstrate that proposed NS scheme outperforms LDPC-coded 8-QAM by 0.8 dB.