Determine the frequency band(s) your device will use for wireless communication. The WPC regulates the use of radio frequency spectrum in India and assigns frequency bands to different types of wireless devices.

Ensure that your device complies with the technical specifications and safety requirements set by the WPC for wireless communication devices. This may involve testing the device's electromagnetic compatibility, power output, and other performance parameters.

Apply for WPC approval by filling out an application form and providing the required documentation, such as test reports, user manuals, and circuit diagrams.

Pay the required fee for WPC approval and wait for the approval process to be completed. The process may take several weeks or months, depending on the complexity of the device and the workload of the WPC.

Once your Smart Home Gateway has been approved by the WPC, you can use it for wireless communication in India and market it as WPC-approved. You will need to comply with the ongoing regulatory requirements for wireless communication devices, such as obtaining renewal of the approval certificate and reporting any changes in the device's specifications or usage.