Modulation: QPSK to 256QAM

Packing Bits Into Symbols

NR supports four modulation schemes that trade robustness for spectral efficiency. QPSK maps 2 bits per symbol using four widely spaced constellation points, making it reliable even at very low SINR around zero dB. 16QAM maps 4 bits per symbol with sixteen points, 64QAM maps 6 bits per symbol with sixty-four points, and 256QAM maps 8 bits per symbol using a dense grid of 256 constellation points. Each step up in modulation order doubles the data carried per symbol but places the constellation points closer together, demanding a cleaner signal with progressively higher SINR to distinguish them…