When I worked on this was a few years ago, so NFC wasn't a viable option at the time. I think even today, some research would need to be done on how widespread support is, we can't guarantee everyone has a brand new phone. but I agree NFC would be worth serious consideration now.
When considering robustness of support, one nice thing about the WIFI approach is in theory you can fall back to just a web browser. So basically any device could be used for provisioning.
And the audio method, would probably support a great set of devices. We didn't actually consider ultrasonic, just an audio codec that was in use at the time and doesn't sound awful.
When considering robustness of support, one nice thing about the WIFI approach is in theory you can fall back to just a web browser. So basically any device could be used for provisioning.
And the audio method, would probably support a great set of devices. We didn't actually consider ultrasonic, just an audio codec that was in use at the time and doesn't sound awful.