When T-Mobile announced this week that it was going to be calling its high-speed HSPA+ data network "4G," it made a good point. Assuming that you define 4G as being 'really fast,' then T-Mobile's claim was well-founded. Its network, regardless of its G level, is fast, and my tests proved it. But as you might imagine, everyone who isn't T-Mobile has started screaming about how T-Mobile's HSPA+ really isn't 4G, really isn't any faster, or really isn't as big as the company boasts.
This should be no surprise. Sprint and other related WiMax companies claim that they have the only real 4G network around, since the International Telecommunications Union mentions WiMax as one type of 4G in its specs. The other type of communications mentioned is LTE, and Verizon Wireless is still deploying that. AT&T hasn't been claiming 4G because it doesn't have it. AT&T has HSDPA in some places, and other places are being upgraded to HSPA. There are a few places where AT&T has upgraded its data service to HSPA+ that's very similar to what T-Mobile has deployed nationally.
WiMax vendor Beceem was one of the first with a press release asserting that T-Mobile is falsely claiming to be using a 4G technology. Beceem instead claims that only Sprint (and, of course, Beceem, which makes some of the gear) has real 4G. Verizon Wireless has so far stayed out of the fray, probably due to some innate level of sanity on its part.
So, since there seems to be some disagreement as to what constitutes 4G and what doesn't, let's clear this up. First, nobody, including Sprint or Beceem, has a 4G solution. If they claim to, they're stretching the truth. Second, T-Mobile doesn't have 4G either, and neither does AT&T.
Regardless of the mode of transmission, the ITU requires 4G to include download speeds of 100 Mbps for mobile devices, and 1 Gbps for fixed or portable devices. Nobody in the United States is even close. WiMax doesn't make the cut, what with its pokey 10 Mbps speeds. T-Mobile may be twice as fast, but it's not 4G either. So while both sides may fire press releases at each other, you can safely ignore them. No matter what they say, it's not 4G.
But there's the second part of the question, which is, which network is really fast? Sprint's gear claims 4G status, but delivers far less. With its laptop USB stick, you might get 12 Mbps. T-Mobile can deliver 21 Mbps to its laptop USB stick. AT&T has a USB stick similar to the one from T-Mobile, but there are no phones that can run nearly that fast. T-Mobile has two so far, and is releasing more. The difference between the HSPA+ from T-Mobile and AT&T is that it can be upgraded easily to eventually come close to 4G speeds demanded by the ITU. It's not clear that current WiMax technology will ever do that. The ITU says it will be WiMax 2 when that happens. In other words, Sprint and Beceem are wrong. AT&T and T-Mobile might be right eventually.
Meanwhile, what you're hearing is dueling marketing departments' attempts to sow FUD.
But you don't care. What actually matters is which network is actually fast enough to make a difference. Right now, that's T-Mobile. But that matters only if you're located in an area with T-Mobile's HSPA+. If you're not, the it's just one more set of claims that don't matter because you can't do anything with them.