CWNA: Certified Wireless Network Administrator v107 — Question 17

What statement is true concerning the use of Orthogonal Frequency Division Multiplexing (OFDM) modulation method in IEEE 802.11 WLANs?

Answer options

• A. OFDM was used by Frequency Hopping Spread Spectrum (FHSS) PHY devices.
• B. OFDM was first introduced in 802.11 and is used by the ERP, HT and VHT PHYs as well.
• C. OFDM implement BPSK modulation to allow for data rates up to 7 Gbps.
• D. OFDM modulation is used only in 5 GHz 802.11 transmissions.

Correct answer: D

Explanation

The correct answer is D because OFDM is primarily associated with 5 GHz transmissions in the IEEE 802.11 standards. Options A, B, and C are incorrect as they either misattribute the use of OFDM or provide inaccurate details about its capabilities and applications.