AT&T is working to bolster its claim of having "America's Fastest 3G Network," by rolling out HSPA 7.2 in six cities by year-end. The speed improvements are nice, sure, but they alone won't help the legions of angry subscribers who experience dropped calls and spotty service.

The rollout of HSPA 7.2 in Charlotte, Chicago, Dallas, Houston, Los Angeles, and Miami has nothing to do with capacity, and it will have no effect on users of older phones. This is purely a speed boost, supporting theoretical download speeds of 7.2 Mbps, and only helps users whose phones support HSPA 7.2. That means the iPhone 3GS will feel the difference, but the iPhone 3G won't.

What's really important are the backhaul improvements AT&T is performing alongside the HSPA 7.2 rollout. Backhaul is a crucial aspect in having a smooth calling experience, so by adding capacity there is a more significant improvement than the speed boosts AT&T is touting. In each market where AT&T rolls out HSPA 7.2, the carrier will improve backhaul capacity as well.

AT&T subscribers who complain about weak signals indoors may also find solace in the rollout of the 850-MHz 3G spectrum. This additional band of coverage could reach people who previously had trouble getting bars, and has the added benefit of boosting capacity by taking people off the existing band. San Francisco may have noticed the difference last month, and AT&T says the spectrum is now open for 90 percent of its network. The timeline for the remaining 10 percent isn't clear.

AT&T is also boasting of 2,000 new cell phone towers in 2009, which should help improve coverage overall. All told, the carrier is investing $18 billion in its network this year.

Thing is, with all these capacity and coverage related improvements in mind, why did AT&T place the HSPA 7.2 rollout front-and-center in its announcement? Speed is nice, but it's meaningless if the underlying service is terrible, and some reports missed the most important part of the message.

I guess "America's Fastest 3G Network" has a better ring to it than "More Tolerable Than Ever."