All carriers that allow signal boosters on their networks must have customers register their locations. 

Register or update your booster

You'll need your account number (located on your T-Mobile bill) and your device information. If you're unable to locate it, check the user manual. Register your device if you have recently:

• Received a new signal booster from T-Mobile, your device is already registered to the shipping address! Set up your booster.
• Moved to a new address, use  Signal Booster Registration​ and select update.
• Purchased your own booster, use Signal Booster Registration and select register.

Why we need to register your booster

• T-Mobile needs the registration to locate the addresses of signal boosters and, if necessary, to contact the owners.
• This ensures signal boosters don't interfere with cellular coverage. Our engineers can use the information to resolve network problems in your area.
• The FCC mandates signal boosters to be registered for this reason. Read more at: http://wireless.fcc.gov/signal-boosters/index.html​.
• Any information you provide us is subject to T-Mobile's Privacy Policy.