T-Mobile declared its HSPA+ network to be "4G" today, claiming that it has the nation's largest 4G network. The company is also charting out a path beyond its current 21 Mbps speeds, potentially all the way up to 168 Mbps in the future.

Launching a major ad campaign, the carrier said it had turned on HSPA+ in six more metro areas including Chicago, announced the retail availability of the myTouch 4G phone, and announced a Dell Inspiron Mini 10 netbook with HSPA+ built in.

"By the end of this year, we'll have two times [the coverage] out there from anything approaching a competitive LTE or WiMAX footprint," T-Mobile chief network officer Neville Ray said.

What Is 4G, Anyway?

The definition of "4G" has been in dispute, most recently because the global body charged with setting wireless standards, the ITU, declared that nothing being sold in the U.S. as 4G is actually 4G. So everyone has their own definitions now, and T-Mobile wants to make it clear that its HSPA+ is at least as fast as Sprint's "4G" WiMax.

"In the majority of markets where WiMAX has actually been launched we're seeing [HSPA+] performance that often matches and beats the performance of those networks," Ray said.

So what is 4G, in T-Mobile's view? It's "a network that's capable of delivering true high-speed performance" with "IP-capable backhaul." And that excludes AT&T's new HSPA+ 14.4 network.

"14.4 is really still HSPA and not from a network perspective true HSPA+," Ray said.

The Road to 168 Mbps

Beyond the trash-talking, Ray laid out the future of HSPA+ at T-Mobile. In 2011, T-Mobile customers will see many more HSPA+ 21 and 42 Mbps compatible devices, he said. T-Mobile's two HSPA+ phones at the moment only support the 14.4 Mbps level of the standard.

During the second half of next year, T-Mobile will start to move to 42 Mbps in most of the carrier's cities. That requires double the spectrum of 21 Mbps, so it can't do it quite everywhere. In 2012, T-Mobile will upgrade its network to the 84 Mbps level of the HSPA+ standard, which uses MIMO antennas on handsets and base stations.

"Then we'll look to see how well the 168 Mbps scenarios mature, and we'll start that push for standardization beyond 168," Ray said.

T-Mobile has enough AWS 1700 Mhz spectrum for its current plans, Ray said; as things go forward, it can bond the AWS spectrum with 1900 MHz PCS spectrum and buy more spectrum in potential upcoming AWS auctions, he said.

That doesn't mean T-Mobile is writing LTE off. The carrier's parent company, Deutsche Telekom, is enthusiastic about LTE. It's just too early for T-Mobile USA to start with an unproven technology that doesn't even have a way to transmit voice calls, Ray said.

"There's going to be a better entry point for LTE than the one that would be there today," he said.