802.11 Co-existence: Trusted Wireless 2.0
Trusted Wireless 2.0 is a proprietary protocol found in industrial environments based on the WirelessHART standard.
In the ISM 2.4GHz band, Trusted Wireless 2.0 uses frequency hopping spread spectrum across 440 possible channels. The protocol will select 127 channels from the possible 440. Blacklisting is implemented to avoid channels that contain interference or a high duty cycle. The selection of the channels is done so that enough distance is given between the channels to avoid signal fading.
Trusted Wireless 2.0 also has the capability to operate across multiple RF bands. This means if the 2.4GHz band becomes congested, the protocol can switch to 900MHz or 868MHz for communication.