SWRA733 March   2022 WL1807MOD , WL1837MOD

 

  1.   Trademarks
  2.   Acronyms
  3. 1Introduction
  4. 2 Single-Channel Versus Multi-Channel
    1. 2.1 MRSC Single Radio Network Topology
    2. 2.2 MRMC Single Radio Network Topology
    3. 2.3 Experiment and Results
  5. 3Multi-Channel Challenges and Requirements
    1. 3.1 802.11 Spec Enablers for Role Switch Protections
    2. 3.2 Role Switch Protection Implementations
      1. 3.2.1 AP Based Roles
      2. 3.2.2 STA Based Roles
    3. 3.3 Single Radio Multi-Channel Challenges
    4. 3.4 Single Radio Multi-Channel Key Requirements
  6. 4WL18xx™ Multi-Channel Implementations
    1. 4.1 Arranging the Role Activity Requests by Priority
    2. 4.2 Scheduling the Role Activities
    3. 4.3 Leveraging MRMC to Improve WLAN-BT Coexistence
  7. 5Conclusions
  8.   Appendix

3.1 802.11 Spec Enablers for Role Switch Protections

The MRMC solution is based on time division between the roles. When these roles operate on different channels, it means that for each role there are portions of time in which it is absent (not transmitting and unable to receive) on its operating channel. The typical WLAN operation (and in the original spirit of the 802.11 specification) the rest of the network will normally assume a device (especially an AP) is present on the channel at all time. Therefore, these absences from the channel need to be protected, in terms of their timing and the procedures taken in order to leave the channel.

The IEEE 802.11 WLAN specification provides several tools which can be utilized as protection mechanisms for seamlessly switching between the active roles:

  • CTS-To-Self – no transmissions on channel for a period of time defined by transmitter on this CTS frame (hold peers TX allowing AP role to leave the channel)
  • Power Save Mode – an AP will buffer packets for a STA during PS (hold RX by others to allow STA role to leave the channel)