The drone itself will either transmit the ID information or it will be sent via the phone/controller you are using. This is something that is either going to have to be incorporated into the drone (some type of broadcasting device) or possibly via a firmware upgrade to the app you're using to fly. There is still a lot to be decide. At this point it's probably going to be a couple of years before all drones will have to be in compliance. Actually for now drones less than 250g are not required to have the ID system but I'm not 100% certain that's going to survive the final rule making.