Q: 20
What statement is true concerning the use of Orthogonal Frequency Division Multiplexing (OFDM)
modulation method in IEEE 802.11 WLANs?
Options
Discussion
Makes sense to pick B here.
Option B makes the most sense because OFDM first appeared in 802.11a and then got adopted by ERP (11g), HT (11n), and VHT (11ac) PHYs. The other options either mix up modulation types or bands (like C, which isn't accurate since 2.4 GHz devices can use OFDM too). I'm pretty sure about B but open if someone's got another angle.
C tbh seems close since OFDM was a big part of 5 GHz 802.11a, but it's not only for 5 GHz because later standards like 802.11g (2.4 GHz) use it too. I thought C might work based on frequency, but looking again, probably not right-correct me if I'm off here.
B got my pick. OFDM was first in 802.11a and then used in the later PHYs like ERP (11g), HT, and VHT. The other options mix up frequency bands or mention FHSS, which never used OFDM. Pretty confident here but let me know if I'm missing something major.
Don’t think it’s C. B fits since OFDM started in 802.11a and is used by ERP, HT, and VHT PHYs too.
Pretty sure B, not C. C is tempting if you only think about 802.11a, but OFDM got used in later PHYs (like ERP and HT) in both 2.4 and 5 GHz bands. Pretty sure B is safest pick here.
C/D? Not sure, C is a trap since OFDM isn't only for 5 GHz but wording might confuse.
OFDM wasn't just for 5 GHz, so C isn't quite right. Best fit here looks like B, since OFDM started in 802.11a and carried into later PHYs (ERP, HT, VHT). Pretty sure but let me know if you see it differently.
It’s B, C is a common trap since OFDM isn’t just for 5 GHz. Pretty sure from other exam reports.
B saw almost this exact question in a practice set. OFDM started with 802.11a and applies to ERP, HT, VHT PHYs too.
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