DVB-S2 and DVB-S2X commonly use which set of modulation schemes with LDPC coding and BCH outer codes?

• A. QPSK, 8PSK, 16APSK, 32APSK with LDPC and BCH outer code
• B. DVB-S2X uses Turbo codes with BPSK
• C. DVB-S2X uses RS codes instead of LDPC
• D. DVB-S2X only supports QPSK

Answer: (A)

DVB-S2 and DVB-S2X use a high‑efficiency LDPC code plus a BCH outer code, and the modulation schemes that are commonly paired with this coding structure are QPSK, 8PSK, 16APSK, and 32APSK. The LDPC inner code handles the main error correction, while the BCH outer code provides additional protection against burst errors, enabling reliable transmission over a range of channel conditions. The modulation choices span from robust low‑order (QPSK) to higher‑order constellations (8PSK, 16APSK, 32APSK) to balance data rate and resilience. Turbo codes are not used in DVB-S2X, RS codes aren’t the outer coding scheme, and DVB-S2X is not limited to QPSK, so those alternatives don’t fit with how these standards are typically implemented.