Well, I quickly skipped down to the conclusion and found this:
We showed that IPs can vary on short time scales on a single device, and that they contain very little information about the locality of the device; cell phones hundreds of miles apart share the same IP address space. These properties of cell phone IPs make IP-based user identi cation and geolocation almost impossible, hampering the ability of websites to blacklist users, display localized content, optimize performance and detect fraud.Seems like a non-starter to me...