Next-generation 4G data networks

If you've ever wished your cell phone would load Web pages faster, you're in luck. All four major U.S. carriers have begun rolling out next-generation 4Gdata networks, at least in major cities. These networks, while utilizing different technologies, all promise sustained, real-world download speeds in excess of 5 megabits per second. That's roughly a five-fold increase over what existing 3G networks are capable of.
It should not come as a surprise that not everyone agrees on the exact definition of "4G." Worse, the ITU, the global body in charge of setting wireless network standards, didn't help the situation when it declared that all current wireless technologies aren't actually 4G. (The ITU has since reversed course and declared that LTE, WiMAX, and HSPA+ can all be branded 4G.)
There are several kinds of 4G. Sprint threw down with Clearwire's WiMAX 802.16e network, which was first out of the gate stateside. Originally branded Xohm, WiMAX-compatible cellular USB modems on Sprint launched in late 2008. But actual 4G-capable smartphones didn't arrive until mid-2010. Arguably the best-known WiMAX smartphone is the HTC EVO 4G, a fast Android device with a 4.3-inch touch screen, a very slim form factor, and HTC's beautiful Sense UI layer. Fire up YouTube, and it kicks into an HD mode that displays crystal clear, widescreen video that's much sharper than the pixelated streams you'd see on most 3G handsets.
Sprint also sells other WiMAX-capable cell phones. Two examples are the Samsung Epic 4G, a unique version of the popular Galaxy S with WiMAX capability and a slide-out QWERTY keyboard, and the HTCEVO Shift 4G, a slightly smaller and less powerful iteration of the EVO 4G, albeit with an added hardware keyboard as well.
WiMAX is fast, but it's not perfect. In our tests, we've found that it has trouble penetrating the outer walls of buildings, at least compared to EV-DO (3G CDMA) devices on Sprint's network. More significantly—and this is a problem throughout the industry, regardless of the 4Gtechnology used—Clearwire is still building out its WiMAX network. Major destinations like San Francisco and Bridgeport, CT only came on line at the end of 2010. For now, expect little to no WiMAX coverage in most suburban and rural parts of the U.S.
Another major 4G option is LTE. AT&T and Verizon are backing this standard in the U.S.—and with approximately 190 million subscribers between the two carriers, it's a significant undertaking. Verizon unveiled its first batch of LTE devices, which includes the HTC Thunderbolt and the dual-core Motorola Droid Bionic 4G. These phones will use LTE for data, but still make voice calls over the existing CDMA network. The first voice-capable LTE phones (VoLTE), which promise much clearer call quality, won't arrive until later.
But leave it to the upstart MetroPCS, of all carriers, to release the first two LTE-compatible devices (on MetroPCS's admittedly very small LTE network): the Samsung Galaxy Indulge smartphone, and the Samsung Craft SCH-R900 feature phone. For its part, Clearwire is already testing a form of 4G LTE that should prove faster than Verizon Wireless's network, as well as its own existing WiMAX network. In fact, there are some indications—including directly from Sprint CEO Dan Hesse—that Sprint may eventually begin abandoning WiMAX as early mid-2011 in favor of an LTE network deployment.
Then there is HSPA+, which is essentially a three-and-a-half-G version of existing 3G HSDPA networks. T-Mobile is hard at work updating its 3G network to HSPA+. AT&T is also building out HSPA+ as a stopgap ahead of LTE, but is being cagey about exactly how fast its version is. While HSPA+'s theoretical maximum speeds are lower, for now, than that of WiMAX and LTE, real world speeds are proving quite similar, at least at the very beginning.
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