A senior network engineer is designing a high-density enterprise WLAN deployment supporting diverse legacy and high-performance real-time applications across multiple frequency bands. Match each IEEE wireless standard or deployment mechanism on the left with its precise operational constraint or physical layer (PHY) capability on the right.
- 802.11ax (Wi-Fi 6) Orthogonal Frequency-Division Multiple Access (OFDMA)Divides individual channels into sub-carriers called Resource Units (RUs) for simultaneous multi-user uplink and downlink communications across both 2.4 GHz and 5 GHz bands.
- 802.11ac (Wi-Fi 5) Wave 2 Multi-User MIMO (MU-MIMO)Supports up to four spatial streams of simultaneous multi-user downlink transmissions operating exclusively within the 5 GHz frequency band.
- 802.11n (Wi-Fi 4) Greenfield ModeEliminates legacy preamble headers to optimize throughput efficiency, preventing fallback compatibility with legacy 802.11a/b/g client stations.
- 802.11a Legacy 5 GHz PHY SpecificationOperates strictly in the 5 GHz band using 52 OFDM subcarriers across 20 MHz channel widths, providing maximum data rates up to 54 Mbps.
Answer
802.11ax OFDMA matches channel division into Resource Units across 2.4 GHz and 5 GHz bands. 802.11ac Wave 2 MU-MIMO matches downlink-only multi-user streams operating exclusively in 5 GHz. 802.11n Greenfield mode matches eliminating legacy preambles to optimize throughput without backward compatibility. 802.11a legacy PHY matches 5 GHz OFDM operation across 20 MHz channels achieving up to 54 Mbps.
The correct matches accurately differentiate between frequency spectrum constraints, multi-user transmission mechanisms (OFDMA vs MU-MIMO), frame preamble modes (Greenfield), and legacy OFDM channel characteristics across IEEE 802.11 wireless deployment standards.
Step-by-Step Solution
Key Concept
Wireless Standards and Physical Layer (PHY) Capabilities