Constellation Design for Low-Complexity Receivers

Non-uniform constellations (NUCs) can significantly reduce error probabilities. However, employing NUCs substantially increases receiver’s demapping complexity due to the nonuniform symbol spacing. To address this challenge, we first propose a novel design concept for non-paired constellations, which allows the transmitter to use sophisticated NUCs while the receiver maintains a simple uniform quadrature amplitude modulation (QAM) constellation. Second, we propose a NUC design method for receivers employing max-log demapping. Numerical experiments with one-dimensional NUC (1D-NUC) demonstrate that our proposed NUC designs achieve up to 0.45dB improvement in error probability for scenarios where the receiver employs uniform QAM and/or max-log demapping.