http://news.cnet.com/8301-30686_3-20022011-266.html
QuoteEarlier this week, T-Mobile USA, the fourth largest cell phone operator in the U.S., launched a marketing campaign calling its newly upgraded network "America's Largest 4G Network."
The claim has ruffled more than a few feathers at T-Mobile competitors, namely Sprint Nextel, which has been helping its partner Clearwire build a nationwide network using a technology called WiMax that it claims is 4G (http://news.cnet.com/Sprint-Nextel%2C-Clearwire-plan-nationwide-WiMax-network/2100-1039_3-6197569.html).