Which type of forward error correction does the 200G WDM line card for the NCS 2000 use to achieve maximum distance?

Question

Options

• Ahard-decision FEC
• Bgeneric FEC
• Cquadrature amplitude FEC
• Dsoft-decision FEC

• A
  9% (3)
• B
  3% (1)
• C
  16% (5)
• D
  72% (23)

Explanation

Soft-decision FEC (SD-FEC) achieves maximum distance because it operates on analog signal probabilities rather than forcing each received bit into a hard 0/1 decision before correction - this "soft" information yields roughly 2–3 dB more coding gain over hard-decision approaches, directly extending reach on the 200G WDM line card.

Hard-decision FEC (A) discards the analog confidence levels and works only with binary bit decisions, resulting in lower coding gain and shorter achievable distances - it's simpler but less powerful.

Generic FEC (B) is not a recognized FEC category in optical standards; it's a meaningless distractor combining a vague adjective with a real term.

Quadrature amplitude FEC (C) conflates two unrelated concepts - QAM (quadrature amplitude modulation) is a modulation scheme, not an error correction type; no such FEC exists.

Memory tip: Think "Soft = Superior reach" - soft-decision FEC keeps the signal's analog nuance alive during correction, just as a soft answer considers nuance rather than forcing a hard yes/no. If a question asks about maximum distance, reach for soft-decision FEC.

No community discussion yet for this question.