silabs.com | Building a more connected world. Rev. 1.7
AN1017: Zigbee
®
and Silicon Labs
®
Thread
Coexistence with Wi-Fi
This application note describes the impact of Wi-Fi on Zigbee and
Silicon Labs Thread and methods to improve coexistence with Wi-
Fi. These techniques are applicable to the Mighty Gecko family
(EFR32MGx). First, design considerations to improve coexistence
without direct interaction between Zigbee/Silicon Labs Thread and
Wi-Fi radios are described. Next, Silicon Lab’s Packet Traffic
Arbitration (PTA) support to coordinate 2.4GHz RF traffic for co-
located Zigbee/Silicon Labs Thread and Wi-Fi radios is described.
Finally, methods for using the coexistence CLI commands are
discussed.
This application note describes EFR32 Zigbee and Silicon Labs Thread coexistence sup-
port for EmberZNet PRO 6.6.1.0 and Silicon Labs Thread 2.10.1.0. See Section 9 Revi-
sion History for a summary of key changes in previous revisions of this application note.
Additional details about the implementation of managed coexistence and test results are
available in an expanded version of this application note, AN1017-NDA: ZigBee and
Thread Coexistence with Wi-Fi, available under non-disclosure from Silicon Labs tech-
nical support.
KEY POINTS
• Wi-Fi impact on Zigbee/Silicon Labs
Thread
• Improving unmanaged coexistence
• Implementing managed coexistence
• Using the coexistence CLI commands
AN1017: Zigbee® and Silicon Labs® Thread Coexistence with Wi-Fi
Contents
silabs.com | Building a more connected world. Rev. 1.7 | 1
Contents
1 Introduction ........................................................................................................................................................................................ 3
2 Wi-Fi Impact on Zigbee/Silicon Labs Thread ..................................................................................................................................... 4
3 Unmanaged Coexistence ................................................................................................................................................................... 8
3.1 Implement Frequency Separation ......................................................................................................................................... 8
3.2 Operate Wi-Fi with 20MHz Bandwidth .................................................................................................................................. 8
3.3 Increase Antenna Isolation.................................................................................................................................................... 8
3.4 Use Zigbee/Silicon Labs Thread Retry Mechanisms ............................................................................................................ 9
3.5 Remove FEM (or Operate FEM LNA in Bypass) ................................................................................................................... 9
4 Managed Coexistence ..................................................................................................................................................................... 10
4.1 PTA Support Options .......................................................................................................................................................... 10
4.1.1 1-Wire PTA ........................................................................................................................................................... 12
4.1.2 2-Wire PTA ........................................................................................................................................................... 12
4.1.3 3-Wire PTA ........................................................................................................................................................... 12
4.1.4 4-Wire PTA ........................................................................................................................................................... 12
4.1.5 Single EFR32 Connected to Wi-Fi/PTA Transmit Timing ..................................................................................... 12
4.1.6 Single EFR32 Connected to Wi-Fi/PTA Receive Timing ...................................................................................... 12
4.1.7 Directional PRIORITY Transmit Timing (Single EFR32) ....................................................................................... 12
4.1.8 Directional PRIORITY Receive Timing (Single EFR32) ........................................................................................ 12
4.1.9 Multiple EFR32s Connected to Wi-Fi/PTA ............................................................................................................ 13
4.1.10 Multiple EFR32s Connected to Wi-Fi/PTA Transmit Timing ................................................................................. 14
4.1.11 Multiple EFR32s Connected to Wi-Fi/PTA Receive Timing .................................................................................. 14
4.1.12 Directional PRIORITY Transmit Timing (Multiple EFR32s) ................................................................................... 14
4.1.13 Directional PRIORITY Receive Timing (Multiple EFR32s) .................................................................................... 14
4.1.14 Wi-Fi/PTA Considerations .................................................................................................................................... 14
4.1.14.1 Wi-Fi/PTA Supports Wi-Fi TX Pre-emption ..................................................................................... 15
4.1.14.2 Wi-Fi/PTA Prevents Wi-Fi Transmit when GRANT Asserted .......................................................... 15
4.1.14.3 Wi-Fi/PTA and Application Implements Reasonable Prioritization .................................................. 15
4.1.14.4 Wi-Fi/PTA Implements Aggregation ................................................................................................ 15
4.1.14.5 Wi-Fi/PTA Supports Directional PRIORITY ..................................................................................... 15
4.1.15 TX PRIORITY Escalation ...................................................................................................................................... 16
4.1.16 PWM for High Duty Cycle Wi-Fi ............................................................................................................................ 16
4.1.16.1 Background ..................................................................................................................................... 16
4.1.16.2 PWM Feature Description ............................................................................................................... 17
4.1.16.3 PWM Implementation ...................................................................................................................... 18
4.1.17 Directional PRIORITY ........................................................................................................................................... 19