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Low-power system design with AIROC™ Wi-Fi & Bluetooth® combo
chip and PSoC™ 6 MCU
WLAN power optimization techniques
AP
STA1
Slave listening to Beacon @ DTIM interval
(With PS without
Poll)
Figure 4
Power save without poll
3.1.4.3
Association timeout limit
If an STA does not expect to receive directed frames from the AP asynchronously, and it is not interested in
receiving broadcast or multicast traffic, then further power savings may be achieved.
Because APs generally have an association timeout limit with a default value of 60 seconds, an STA that uses
power save must wake up before the association timeout expires and send or receive a directly addressed
frame to inform the AP that the STA is still associated. Failure to comply results in the AP de-authenticating the
STA. Some APs allow the association timeout limit to be set to a value higher than 60 seconds, but the higher
limit is not signaled to the station and must be manually configured.
3.1.5
802.11ac-friendly features
AIROC™ CYW43012 Wi-Fi & Bluetooth® combo chip provides 802.11ac friendliness by supporting 256-QAM (for
20-MHz channels in the 5-GHz band) enabling data rates of up to 78 Mbps with 802.11ac APs. This enables
superior throughput and reduced power consumption in the device by sending/receiving data and then going
back to sleep faster. In addition, it supports 802.11ac's 'explicit beamforming' feature to offer significantly
higher throughputs than 802.11n chipsets at any given range.
3.2
Wi-Fi power save implementation
3.2.1
Wi-Fi Host Driver (WHD) power save interface
The power save implementation is provided as part of the
implement their power save mechanisms on top of the WHD to provide users with seamless low-power
integration.
Table 4
describes the low-level functions available as part of WHD providing various power save features. Refer
to the
WHD API reference guide
Table 4
WHD power save APIs
WHD API
whd_wifi_enable_powersave()
Application note
DTIM = 3
Beacon with
TIM
DTIM
Null frame from STA1
with PM bit cleared
for details.
Description
Enables PS-poll mode in the device (see
TIM with data for
STA1
WHD
library. In addition, platforms such as FreeRTOS
13
Data for STA1
Power save
poll)
002-27910 Rev. *C
2023-05-29
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