What Exactly Is '4G'?What Exactly Is '4G'?

The term "4G" is being tossed around a lot in the tech industry right now, and in some instances is being misapplied. information takes a few moments to to help sort out this alphabet soup and explain what's really going on here.First and foremost, there is no "iPhone 4G." This is a misnomer created by people who don't know what's what. Whatever Apple decides to call the next version of the iPhone, it most likely won't be the 4G -- for several reasons. The iPhone 3G was called the 3G because it added 3G to what was previously a 2.5G device. The likelihood of Apple adding a 4G radio to support 4G networks that aren't even available yet is slim to none. And while the 2010 iPhone will be the fourth version of the iPhone, I believe Apple is smart enough to avoid the 4G label. So what, then, is 4G?

Simply put, 4G is what comes after 3G. Today's wireless broadband networks are powered by 3G - short for third-generation -- technology. In the U.S., that means HSDPA/UMTS and CMDA EVDO radio technologies. These are currently used by AT&T/T-Mobile and Sprint/Verizon, respectively. The 3G standard was devised by the 3GPP2 organization. The same and other standards bodies are working to finalize what 4G -- or fourth generation -- wireless networks will include. The standard has not been finalized.

Let me repeat that: The standard has not been finalized. Without a finalized standard, technically speaking, 4G hasn't been defined and doesn't exist. Any company claiming to offer 4G products and/or services is not telling the entire truth (hell, it might even be misleading consumers).

Fourth generation wireless networks are to be IP-based, and must meet the IMT (International Mobile Telecommunications) Advanced criteria. According to the IEEE, IMT-Advanced requires the following:

In the U.S., Sprint and Clearwire are building a next-generation wireless broadband network using WiMax technology. Right now, mobile WiMax (802.16e) offers peak downloads of 128Mbps on the download and 56Mbps on the upload over 20MHz wide channels. Despite the potential performance levels of WiMax, the current spec doesn't yet meet all the IMT-Advanced requirements. It is possible that 806.16m will meet those requirements, making WiMax a true 4G technology. It hasn't been ratified yet.

Long Term Evolution, which will eventually be deployed by Verizon Wireless, AT&T and T-Mobile, is termed a "pre-4G" technology. LTE has the theoretical capacity to reach 100Mbps down and 50Mbps up in a 20MHz channel. In its current form, LTE doesn't meet the IMT-Advanced criteria, either. A newer version, called LTE Advanced, makes the appropriate changes and should clear the IMT-Advanced hurdle some time in 2011.

So to be clear: With modifications to the current specs, WiMax and LTE might become verified as 4G technologies in the future. Right now, they are not.

You know what else is not 4G? T-Mobile's HSPA+ network. T-Mobile is marketing its HSPA+ network as "4G like." This bit of marketing lingo used in the company's recent press releases should be squashed ASAP. Based on my experiences, T-Mobile's HSPA+ network is outperforming Sprint's WiMax network in sheer speeds, but HSPA+ is a 3G technology through and through. To call it anything else is confusing at best, and a disservice to the general public.

To sum up. There is no iPhone 4G. WiMax and LTE might eventually become 4G technologies. And T-Mobile is not offering 4G at all.