802.11n MAC Functions
What is the role of MAC functions in IEEE 802.11n?
MAC functions manage frame delivery, addressing, error detection, and access to the wireless medium.
How does 802.11n MAC differ from previous standards like 802.11a/b/g?
It includes enhancements like frame aggregation, block acknowledgments, and MIMO support for higher throughput.
What is frame aggregation in 802.11n MAC?
Aggregating multiple MAC frames into one larger frame to reduce overhead and increase efficiency.
What types of frame aggregation are supported?
A-MPDU (Aggregated MAC Protocol Data Unit) and A-MSDU (Aggregated MAC Service Data Unit).
How does block acknowledgment improve MAC performance?
It allows acknowledgment of multiple frames with a single response, reducing ACK overhead.
What MAC mechanisms handle retransmissions in 802.11n?
The MAC layer uses selective retransmissions coordinated with block acknowledgments for lost frames.
How does 802.11n MAC support MIMO?
It negotiates spatial stream capabilities and manages frame transmission across multiple antennas.
What is the role of the RTS/CTS mechanism in 802.11n MAC?
It reduces collisions by reserving the medium before transmitting large aggregated frames.
How does MAC handle Quality of Service (QoS) in 802.11n?
Through Enhanced Distributed Channel Access (EDCA) providing prioritized medium access.
What is the function of the MAC sequence control field?
It orders frames correctly and detects duplicates for reliable data delivery.
How does MAC fragmentation work in 802.11n?
It breaks large frames into smaller fragments to improve reliability over noisy channels.
Does 802.11n MAC support power management?
Yes, MAC coordinates power save modes and wake cycles with the AP to conserve energy.
How is MAC security handled in 802.11n?
MAC works with security protocols like WPA2 to encrypt frames and authenticate devices.
What is the role of the MAC address field?
It identifies source, destination, and BSS for correct frame delivery.
How does the MAC layer interact with the PHY layer?
It coordinates frame transmission timing, modulation, and error correction with the PHY layer.
What MAC timing parameters are crucial in 802.11n?
SIFS, DIFS, backoff timers, and acknowledgement timing for efficient medium access.
How does the MAC layer support roaming in 802.11n networks?
It handles reassociation and handoff procedures to maintain connectivity.
What is the role of management frames in MAC?
To manage network operations like association, authentication, and beaconing.
How does MAC error detection work?
Using CRC checksums to detect corrupted frames before passing to higher layers.
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