Power Saving Mechanisms in IEEE 802.11bn protocol
What is the primary goal of power saving mechanisms in 802.11bn?
To extend battery life of devices while maintaining connectivity and network performance in mixed b/n environments.
How does 802.11bn handle power saving differently than pure 802.11n?
It balances modern power-saving features with legacy 802.11b compatibility, which can add overhead and affect efficiency.
What is Power Save Mode (PSM) in 802.11bn?
Stations enter sleep mode to conserve power and periodically wake to receive buffered frames from the AP.
How do stations notify the AP when entering or exiting Power Save Mode?
By setting or clearing the Power Management bit in transmitted frame headers.
What is the role of the Traffic Indication Map (TIM) in 802.11bn?
TIM bits in beacon frames inform stations about buffered unicast frames waiting at the AP.
How does the Delivery Traffic Indication Message (DTIM) function in 802.11bn?
It signals buffered multicast and broadcast traffic, prompting sleeping stations to wake and receive it.
Does 802.11bn support Unscheduled Automatic Power Save Delivery (U-APSD)?
Yes, to improve QoS and reduce latency for power-saving clients.
What is the significance of PS-Poll frames in 802.11bn power saving?
Stations use PS-Poll frames to request delivery of buffered unicast frames from the AP while in sleep mode.
How do legacy 802.11b devices impact power saving efficiency in 802.11bn networks?
They require protection mechanisms and longer preambles, which increase airtime and reduce power-saving benefits.
Can stations in 802.11bn receive multicast traffic while in power save mode?
Yes, multicast traffic is buffered and sent after DTIM beacons wake sleeping stations.
What is the Listen Interval and how does it affect power saving in 802.11bn?
The number of beacon intervals a station sleeps before waking to check buffered data; longer intervals save more power but increase latency.
How do APs coordinate power saving with mixed 802.11b and 802.11n clients?
By using protection mechanisms like RTS/CTS and managing buffered frames to minimize interference and power use.
Does frame aggregation in 802.11bn improve power saving?
Yes, by reducing overhead and transmission time, stations can return to sleep faster.
What impact do beacon interval lengths have on power saving in 802.11bn?
Longer beacon intervals allow longer sleep periods but can increase latency for receiving buffered frames.
How do stations handle missed beacons during power save mode in 802.11bn?
Missing beacons may delay delivery of buffered frames and cause retransmissions, impacting efficiency.
Are power save mechanisms in 802.11bn compatible with MIMO and multiple spatial streams?
Yes, power saving applies across spatial streams with coordination for aggregated frame delivery.
Is special AP support required for U-APSD in 802.11bn?
Yes, APs must support U-APSD to coordinate automatic frame delivery and minimize wake time.
What challenges do legacy 802.11b clients introduce to power saving in 802.11bn?
They increase airtime due to slower rates and protection overhead, reducing overall power saving effectiveness.
How do power saving mechanisms balance battery life and network performance in 802.11bn?
By scheduling sleep/wake cycles and buffering, devices optimize energy use while maintaining timely data delivery.
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