Samsung Electronics Co. Ltd. will bring what it is calling the fastest smartphone yet, the Inspire 4G, to AT&T Inc. on May 15. The phone will be the first to run on AT&T's HSPA+ network at 21Mbit/s.

AT&T has the largest HSPA+ of any of its competitors, and it plans to tout this advantage even as it rolls out Long Term Evolution (LTE). To do that, it's going to need smartphones that take advantage of the faster speeds and support simultaneous voice and data. (See CES 2011: AT&T Accelerates LTE Push.)

"So the Infuse 4G really is HSPA+, unlike the Inspire, Atrix, and Veer. Take note!" tech blogger Chris Ziegler tweeted, jibing AT&T for wavering on its definition of 4G in the past.

For what it's worth, the carrier has now taken a definitive stand, telling PC Mag that it defines 4G as "14.4Mbit/s devices connected to high-speed backhaul at cell sites."

They say
That makes the Infuse (along with the 14.4 Mbit/s Hewlett-Packard Co. Veer, also launching May 15) the first truly 4G smartphone for the carrier, by its own definition. And it appears to be a good start. Boy Genius Report blogger Jonathan Gellar writes, "This is by far our favorite Android device from Samsung so far."

The $199 smartphone is also Samsung's thinnest at 8.99mm and largest Super AMOLED display at 4.5 inches. CNET was impressed that the phone didn't feel "so plasticky and slick like the first-generation of Galaxy S phones," and called the massive device's screen sharp and vibrant.

A few reviews expressed disappointment that the phone will only be running Android 2.2 at launch and that it features a single-core processor, not the dual-core that's becoming common in advanced devices. Techno Buffalo Editor-at-Large Noah Kravitz also questioned the validity of the 4G speeds. "AT&T Samsung Infuse 4G ... stretches the definition of '4G' just a little bit IMO [in my opinion]," he tweeted.

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The definition of 4G has become so convoluted that Light Reading Mobile made up its own name for it: FauxG. More important is how the device performs.

AT&T will need to continue to add to its lineup of strong smartphone performers as it gears up for an LTE launch later this year. The carrier plans to add more than 20 additional 4G devices to its lineup this year, as it confirmed at an event with Samsung to launch the phone.

• AT&T's LTE Plans Provide Clue to iPhone 5 Launch
• RIM PlayBook: LTE & HSPA+ Versions Coming
• Apple iPhone 5: Falling for 4G?
• AT&T Confirms Move to 21Mbit/s HSPA+
• AT&T Speeds Up 80% of Its 3G Network

— Sarah Reedy, Senior Reporter, Light Reading Mobile