Developed to enable low-cost, commercial and smart home networks, MiWi is used in applications such HVAC systems and Alarm sensors where reliable sub-GHz connections and long battery life are needed.
MiWi also runs in the 2.4GHz worldwide ISM band. The MiWi protocol runs on the IEEE 802.15.4 RF Physical Layer.
The MiWi stack offers a significantly smaller foot-print relative to the open standard based ZigBee® compliant protocol stack. This enables operation in microcontrollers with smaller memory / lower cost.
Click https://www.microchip.com/design-centers/wireless-connectivity/embedded-wireless/802-15-4/software/miwi-protocol for details.