SWRU423A July   2015  – May 2016 WL1801MOD , WL1805MOD , WL1807MOD , WL1831MOD , WL1835MOD , WL1837MOD

 

  1.   WiLink 8 WLAN Features Guide
    1.     Trademarks
    2. 1 Introducion
      1. 1.1 Scope
      2. 1.2 Acronyms Table
      3. 1.3 WiLink 8 Specification
    3. 2 General Features
      1. 2.1  Supported Rates
        1. 2.1.1 11b Rates
        2. 2.1.2 11a/g Rates
      2. 2.2  High-Throughput (HT) Features
        1. 2.2.1 11n Rates
        2. 2.2.2 MIMO at 2.4 GHz
        3. 2.2.3 40-MHz BW Operation
        4. 2.2.4 A-MPDU and A-MSDU
        5. 2.2.5 RIFS
        6. 2.2.6 BA Sessions
        7. 2.2.7 Greenfield
      3. 2.3  Quality of Service (QoS)
      4. 2.4  Protection Types
        1. 2.4.1 General
        2. 2.4.2 Protection Methods
      5. 2.5  Suspend and Resume
      6. 2.6  WoW (Wake on WLAN)
      7. 2.7  Set TX Power
      8. 2.8  5-GHz Antenna Diversity
      9. 2.9  Wi-Fi – Bluetooth/Bluetooth Smart Coexistence
      10. 2.10 Wi-Fi – ZigBee Coexistence
      11. 2.11 Accurate Synchronization Over Wi-Fi
    4. 3 Single Role: Station
      1. 3.1  Scanning
        1. 3.1.1 One-Shot Scan
        2. 3.1.2 Connection Scan
        3. 3.1.3 Background Scan
      2. 3.2  Connection
        1. 3.2.1 Manual (Via Commands)
          1. 3.2.1.1 Connection Time
          2. 3.2.1.2 Connection Success Rate
          3. 3.2.1.3 Connect to Best BSSID of the Configured SSID
        2. 3.2.2 Automatic (Via Profiles)
        3. 3.2.3 Wi-Fi Protected Setup (WPS)
          1. 3.2.3.1 WPS PBC
          2. 3.2.3.2 WPS PIN
      3. 3.3  Disconnection
      4. 3.4  DHCP Client
      5. 3.5  Security
        1. 3.5.1 Authentication Types
        2. 3.5.2 Encryption Types
        3. 3.5.3 Broadcast Key Rotation (BKR)
      6. 3.6  Filtering
        1. 3.6.1 Beacon Filtering
        2. 3.6.2 Multicast Filtering
      7. 3.7  Auto ARP
      8. 3.8  Preferred Networks (Profiles)
        1. 3.8.1 Hidden Network
      9. 3.9  Power-Save Mode
        1. 3.9.1 Active
        2. 3.9.2 Auto Power-Save Mode
        3. 3.9.3 Forced Power-Save Mode
      10. 3.10 Power-Save Delivery Protocols
        1. 3.10.1 Legacy
        2. 3.10.2 U-APSD
      11. 3.11 Keep-Alive Mechanism
      12. 3.12 Smart Config
      13. 3.13 Regulatory Domain
      14. 3.14 DFS Slave (Channel Switch)
      15. 3.15 Roaming
        1. 3.15.1 Roaming Mechanism
          1. 3.15.1.1 Mechanism Enabling
          2. 3.15.1.2 Roaming Candidates List
          3. 3.15.1.3 A Decision to Roam
          4. 3.15.1.4 Connection to a Better AP
        2. 3.15.2 Roaming Triggers
          1. 3.15.2.1 RSSI Level Delta
          2. 3.15.2.2 APs Disappearing
    5. 4 Single Role: AP
      1. 4.1  Connection
      2. 4.2  Hidden SSID
      3. 4.3  Security
      4. 4.4  Regulatory Domain
      5. 4.5  AP Scan
      6. 4.6  Automatic Channel Selection (ACS)
        1. 4.6.1 40-MHz Operation
        2. 4.6.2 ACS Whitelist and Blacklist Channels
      7. 4.7  Maximum Connected Stations
      8. 4.8  Aging
      9. 4.9  DFS Master
        1. 4.9.1 DFS Standards
        2. 4.9.2 DFS Mechanism
        3. 4.9.3 WiLink8.0 DFS Master Capabilities
      10. 4.10 Access Control
        1. 4.10.1 Blacklist
        2. 4.10.2 Whitelist
      11. 4.11 Extreme Low Power (ELP)
    6. 5 Single Role: P2P
      1. 5.1 P2P Device
        1. 5.1.1 Searching Phase
        2. 5.1.2 Negotiation
        3. 5.1.3 Group Formation
      2. 5.2 PSP Client
      3. 5.3 P2P GO
    7. 6 Single Role: Mesh
      1. 6.1 Supported Modes
        1. 6.1.1 Mesh Point
        2. 6.1.2 Mesh Portal/Gate
        3. 6.1.3 Mesh Access Point
      2. 6.2 Hardware and Software Requirements
        1. 6.2.1 Hardware requirements
        2. 6.2.2 Software Requirements
      3. 6.3 Capabilities
    8. 7 Multi-Role
      1. 7.1 General Overview
      2. 7.2 Limitations
    9. 8 Performance
      1. 8.1 Single-Role
      2. 8.2 Multi-Role
      3. 8.3 AP and mBSSID (Dual AP) Fairness
        1. 8.3.1 AP Fairness: 1-to-10 Stations Throughput Distribution
        2. 8.3.2 mBSSID Fairness: 10 Stations Throughput Distribution
      4. 8.4 Bluetooth WLAN Coexistence
        1. 8.4.1 WLAN Single Role – Bluetooth Performance
  2.   Revision History

2.3 Quality of Service (QoS)

The purpose of WLAN QoS is to allow different types of traffic (voice, video, or normal traffic) to have different priorities when approaching the air (trying to send a frame).

The WiLink8 device supports the enhanced distributed channel access (EDCA) QoS. With EDCA, high-priority traffic has a higher chance of being sent than low-priority traffic. On average, a station with high-priority traffic waits less time before it sends its packet than a station with low-priority traffic.

The levels of priority in EDCA are called access categories (ACs). The contention window (CW) can be set according to the traffic expected in each access category, with a wider window needed for categories with heavier traffic. The CWmin and CWmax values are calculated from aCWmin and aCWmax values, respectively, that are defined for each physical layer supported by 802.11e.

EDCA provide four different ACs (from lowest to highest priority):

  • Background (AC_BK)
  • Best Effort (AC_BE)
  • Video (AC_VI)
  • Voice (AC_VO)

The WiLink8 devices (STA and AP) support the EDCA in both software and hardware: while the software maintains the different AC queues, the hardware runs the “Air Approach” in real-time competition.

Table 9 shows the default EDCA parameters.

Table 9. QoS Access Categories

AC CWmin CWmax AIFSN Max TXOP
Background (AC_BK) 15 1023 7 0
Best Effort (AC_BE) 15 1023 3 0
Video (AC_VI) 7 15 2 3.008 ms
Voice (AC_VO) 3 7 2 1.504 ms

The actual EDCA parameters are published by the AP side. When running a WiLink8 device as an AP role, you can configure the EDCA parameters in the TI configuration file. There is no option to disable QoS from the STA role (enabled by default), but there is an option in the hostapd.conf file to disable the QoS.

A frame is handled as a QoS frame only if it arrived from the network with QoS information. Each frame without QoS information is handled as a non-QoS frame. The default parameters of non-QoS frames are the same as best-effort frames (that is also the case when the AP does not support QoS).

The EDCA QoS is compatible with the Wi-Fi Alliance WMM Certification, with a small modification. WMM defines eight different TIDs (Traffic ID 0-7), while each traffic ID (TID) gets a specific AC handling.

In a WiLink8 solution, each TID is automatically assigned to its correlated AC (see Table 10).

Table 10. QoS TIDs

TID AC
0 AC_BE
1 AC_BK
2 AC_BK
3 AC_BE
4 AC_VI
5 AC_VI
6 AC_VO
7 AC_VO

WiLink8.0 devices are fully compliant with Wi-Fi Alliance WMM requirements.