Re: How are over the air updates (i.e., Android L, etc.) transmitted?
Hi there. OTA updates are transmitted in all sorts of ways, depending on the carrier and manufacturer.
If your phone comes from a manufacturer, it can usually be downloaded via WiFi or mobile data. Carriers might limit their updates to their own networks, but usually they do allow using WiFi as long as you have an active SIM with said carrier.
However, sometimes due to size, security or stability issues, some updates are limited to WiFi or to a tethered connection if available (for instance, some Samsung updates require you to download the update to your computer using Kies and then installing it via USB).
In your case, you should be able to download the update since your phone is factory-unlocked and not carrier branded.