Multilevel Coding Schemes Using LDPC Codes with Signal Shaping for Spectral Efficient Data Communication Systems
Tarek Arafa, Wolfgang Sauer-Greff, Ralph Urbansky · 2019
Multilevel coding (MLC) with multistage decoding (MSD) is an effective approach to combine coding and modulation schemes with the capability of achieving a high degree of both power and bandwidth efficiency. However, signal shaping can further improve the performance of this system by adopting the transmitted constellation points to be unequally likely. In this contribution, we apply the capacity approaching low-density parity-check (LDPC) codes with proper code rates as component codes to the MLC/MSD system. Moreover, the system is combined with a tree LDPC-based signal shaping to achieve a shaping gain. Considering different higher order modulation schemes up to 256-QAM the combined MLC[MSD systems with signal shaping are designed and optimized to effectively operate at high spectral efficiencies up to 0.7 [dB]. Simulation results show that this combination can offer a shaping gain up to 0.7 [dB] even for 256-QAM schemes.