Enhancing the Error Performance of 5G New Radio Using Hierarchical and Statistical QAM

The latest mobile network technology, 5G New Radio (NR), utilizes the combination of Low-Density Parity Check (LDPC) codes, which are powerful forward error correction codes and Quadrature Amplitude Modulation (QAM) for data transmission. However, there is still significant research focus to further improve the bit error rate (BER) of 5G NR systems. In this paper, the performance of 5G NR is enhanced using two different modulation techniques: Hierarchical Modulation (HM) and Statistical QAM (S-QAM). HM is employed by altering the spacing between specific QAM constellation points such that high priority bits are given enhanced protection. On the other hand, to improve BER using S-QAM, the spacing between every constellation point is uniformly increased while keeping the same transmission power through the remapping of data on the constellation points based on their probabilities. Modulation mapper functions for both the HM and S-QAM schemes are derived. Simulation results show that E_b/N₀ gains of up to 1.4 dB and 1.6 dB could be achieved with the HM and S-QAM schemes respectively.