802.11 Standards & Protocol Architecture Flashcards

What does OFDMA in 802.11ax allow compared to OFDM in earlier amendments?

Answer: Serve multiple clients simultaneously within a single channel

OFDMA divides a channel into resource units (RUs) allowing the AP to simultaneously transmit to or receive from multiple clients within one TXOP.

Which 802.11 amendment defines fast BSS transition (fast roaming) to reduce handoff latency for voice applications?

Answer: 802.11r

802.11r defines Fast BSS Transition (FT), pre-caching keys to speed up re-authentication during roaming handoffs.

What is the purpose of the 802.11k amendment?

Answer: Radio resource measurement to help clients make better roaming decisions

802.11k provides radio resource management, giving clients neighbor reports and measurements to choose the best AP when roaming.

Which modulation scheme offers the highest data rate in 802.11ax and requires the strongest signal?

Answer: 1024-QAM

1024-QAM encodes 10 bits per symbol, offering the highest data rate in 802.11ax but requiring a very high signal-to-noise ratio.

What is the 802.11 interframe space (SIFS) primarily used for?

Answer: Immediate responses such as ACK, CTS, and Block ACK

SIFS (Short Interframe Space) is the shortest IFS, used for high-priority immediate responses like ACKs and CTS frames.

Which 802.11 feature allows an access point to send data to multiple clients simultaneously using downlink MU-MIMO?

Answer: MU-MIMO introduced in 802.11ac Wave 2

Downlink MU-MIMO was introduced in 802.11ac Wave 2, allowing the AP to transmit different spatial streams to multiple clients at the same time.