SWRU616B September   2023  – April 2024 CC3300 , CC3301 , CC3301MOD , CC3350 , CC3351

 

  1.   1
  2.   CC33xx WLAN Features Guide
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Scope
    2. 1.2 Acronyms Used in This Document
    3. 1.3 CC33xx Specification
  5. 2General Features
    1. 2.1  Supported Rates
      1. 2.1.1 11ax Rates
      2. 2.1.2 11n Rates
      3. 2.1.3 11a/g Rates
      4. 2.1.4 11b Rates
    2. 2.2  A-MPDU and A-MSDU
    3. 2.3  BA Sessions
    4. 2.4  Keep Alive
      1. 2.4.1 STA
      2. 2.4.2 AP
    5. 2.5  Wake on WLAN (WoW)
    6. 2.6  Antenna Diversity
    7. 2.7  Quality of Service (QoS)
    8. 2.8  Security
      1. 2.8.1 Authentication Types
      2. 2.8.2 Encryption Types
    9. 2.9  Wi-Fi Provisioning
      1. 2.9.1 AP Provisioning
      2. 2.9.2 Bluetooth Low Energy Provisioning
      3. 2.9.3 Wi-Fi Protected Setup (WPS)
        1. 2.9.3.1 WPS PBC
        2. 2.9.3.2 WPS PIN
    10. 2.10 Wi-Fi Power Management Modes
      1. 2.10.1 Power Levels
        1. 2.10.1.1 Active
      2. 2.10.2 Power Save Delivery
        1. 2.10.2.1 Legacy Power Save
  6. 3Single Role: Station
    1. 3.1 Scanning
      1. 3.1.1 Active
      2. 3.1.2 Passive
    2. 3.2 Wi-Fi 6
    3. 3.3 Multicast Filtering
    4. 3.4 Preferred Networks
    5. 3.5 Channel Switch
    6. 3.6 Wi-Fi Power Management Modes
      1. 3.6.1 Power Save Delivery
        1. 3.6.1.1 Unscheduled Asynchronous Power Save Delivery (U-APSD)
        2. 3.6.1.2 Target Wake Time (TWT)
      2. 3.6.2 TI Specific Features
        1. 3.6.2.1 Auto Power-Save Mode
        2. 3.6.2.2 Long Sleep Interval
  7. 4Single Role: AP
    1. 4.1 Hidden SSID
    2. 4.2 Maximum Connected Stations
    3. 4.3 Aging
  8. 5Multirole Multichannel
    1. 5.1 AP-STA
    2. 5.2 STA-STA
  9. 6Wi-Fi/Bluetooth Low Energy Coexistence
  10. 7References
  11. 8Revision History

3.6.1.1 Unscheduled Asynchronous Power Save Delivery (U-APSD)

The unscheduled automatic power-save delivery (U-APSD) mechanism is also known as wireless multimedia (WMM) power-save. Legacy power-save methods can decrease the quality of periodic bi-directional traffic consisting of short frames as in VOIP. Because VOIP data should send data periodically on a fixed time (20 msec. for VOIP call), the legacy mechanism is not efficient enough. The U-APSD mechanism was built to optimize the legacy mechanism.

U-APSD is basically a polling scheme, similar to the legacy power-save delivery. However, in U-APSD mode, any transmitted frame, while in power-save mode, acts as a polling frame and triggers the AP to release a buffered frame from the same access category (AC) as the transmitted packet (the number of frames that are released by the AP is configurable and determined during the connection phase). For example, a voice packet releases only voice-buffered packets. If there are no transmitted packs, STA sends QoS null data packets (after the AP publicizes in its beacon that it has data for the specific associated station), which polls the buffered data. This is very efficient for bi-directional traffic streams, such as VOIP call.

As the STA awakes from power save to transmit the data, the STA then takes advantage of it to get any data buffered from the AP. This feature only works if the STA and AP are configured to WMM-enabled.