Chapter 9: BICM in Modern Standards

Learning Objectives

• Explain why every modern wireless standard (5G NR, Wi-Fi 6/7, DVB-S2/S2X) uses BICM, and identify the customisation of the three ingredients (code, interleaver, mapper) in each
• Map the 3GPP NR PDSCH pipeline from transport block to modulation symbol: CRC, LDPC base-graph selection (BG1/BG2), rate matching, scrambling, QAM mapping; and compute the effective rate for a given MCS index on MCS table 1/2/3
• Compute peak spectral efficiency for Wi-Fi 6/7 MCS configurations and interpret the SNR-threshold curves for 1024-QAM and 4096-QAM
• Derive the 32-APSK ring-ratio design for DVB-S2 at a specified code rate and explain why APSK is preferred to QAM over nonlinear satellite channels
• State and prove the adaptive-modulation-and-coding (AMC) optimality theorem — that the throughput envelope $\mathbb{E}[\eta^\star(\text{SNR})]$ is maximised by one MCS per SNR bin — and use it to interpret the staircase curves seen in real link adaptation
• Explain probabilistic amplitude shaping (PAS) as a distribution matcher + BICM encoder + mapper, state the Maxwell-Boltzmann entropy-maximisation theorem, and quantify the asymptotic shaping gain as $\pi e / 6 \approx 1.53$ dB