Are you sure you understand the terms here?
Carrier-grade NAT is, conceptually, little different from the same NAT that your home router has probably been doing for years. The only difference is one of scale (thousands, or tens of thousands of private addresses behind a pool of public addresses, vs. a single /24 network behind a single public address), and where the translation happens (on your router, or on some upstream device).
So what IP address is it you're trying to determine?
The IP address on your local machine? Check your system settings.
The IP address your router uses to communicate upstream (your public IP address in a traditional NAT, or the carrier's internal address)? Check your router settings
The IP address the rest of the world sees (doesn't matter whether you're directly connected, using NAT, or using CNAT)? Something like whatismyip.com is perfectly valid. This is the address other public sites would see you as coming from.