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

3.1 Scanning

A transmitted signal is subject to reflections and refraction on walls, surfaces, and so forth. The receiving node sees signals differing in phase and amplitude. All these signals superposition at the RX antenna, causing an effect called “fading”. Using more than one antenna allows the evaluation of different multipath scenarios to avoid or reduce the effects of fading and interferences.

Scanning is a process Wi-Fi devices use to detect other remote Wi-Fi devices (usually detection of access points before connection). This process can also be used for environment status or other measurements.

There are three primary scan types: Table 11 describes their different purposes and execution. Each scan completes in a different amount of time, depending on variables such as scan type, configuration, and regulatory rules.

The scan execution in the system is independent and can be executed between other Wi-Fi activities. When a scan is executed in parallel to those activities, it can impact things such as throughput or multi-role (MR) scenarios.

Some typical examples:

  • Multi-role scenario, where STA and AP roles run traffic to remote devices. Executing a scan impacts the throughput by up to 80% (during the scan itself) each time a channel is scanned off.
  • Multi-role scenario where STA is connected and AP is idle. Executing a scan could lower the connection success rate of a remote STA to less than 100%.

This should be taken into account when frequently executing scans.

The examples in Table 11 describe the shortest, typical, and longest scan process.

Table 11. Scan Types

Scan Band Channels Type Approximate Duration [msec]
Shortest BG 1-11 Active 500
Typical BG 1-11 Active 3000
A 36-161 (No DFS) Active
Longest BG 1-11 Active 5000
A 36-161 (With DFS) Active + Passive
J 12-14 Passive