T-Mobile rolls out dual-carrier HSPA+ to put it on par with Verizon's LTE

Lynnette LunaIf T-Mobile USA hadn't canceled the majority of its executives' appearances during this year's CTIA Wireless 2011 show thanks to AT&T's (NYSE:T) proposed $39-billion acquisition of the operator, its announcement would have created buzz at the show.

In a press release, T-Mobile announced that it has already deployed dual-carrier HSPA+ that effectively doubles the speed of its HSPA+ 21 network to theoretical speeds of 42 Mbps. T-Mobile has deployed the technology in three markets--Las Vegas, New York and Orlando--with plans to roll out the faster speed technology in 25 markets by mid-2011. It also rolled out its first dual-carrier device, the Rocket 3.0 data stick.

The higher data speeds come about because T-Mobile is taking two 5-megahertz HSPA+ downlink carriers--each supporting theoretical speeds of 21 Mbps--and bonding them together. The resulting bandwidth puts T-Mobile on par with Verizon Wireless' (NYSE:VZ) LTE network, which is available in 39 markets.

Interestingly, HSPA+, which is supposed to be old news in the face of newer LTE technology, was on the lips of many executives during this year's show. Kris Rinne, senior vice president, architecture and planning with AT&T Mobility, touted HSPA+ as a key differentiator for the operator as it rolls out its LTE network beginning this year.

"We're the only U.S. carrier deploying both HSPA+ and LTE,"  Rinne said during FierceWireless'  Path to 4G event. "Why is that important? It's about customer experience. It takes years to build out networks. In the early days of LTE when customers move from LTE to HSPA, it will be a very smooth transition--much different than some of the other competitors."

Rinne was obviously referring to the user experience on Verizon's LTE network. Subscribers roam between LTE and the slower data speeds of CDMA EV-DO. While AT&T only has a handful of HSPA+ markets with enhanced backhaul that enables the enhanced data speeds, it will inherit T-Mobile's work.

Chris Pearson, president of 4G Americas, said HSPA+ has a lot of longevity. The roadmap for the technology shows a path to 168 Mbps using a multi-carrier aggregation by bonding two 20-megahertz HSPA+ downlink carriers. Australia's Telstra is aiming to move to HSPA+ at 84 Mbps this year. The standards body 3GPP2 is considering a move beyond HSPA+ 168 by looking at data speeds of 336 Mbps, and there's even talk of 650 Mbps, Pearson said.

Interestingly, T-Mobile and Nokia Siemens Networks have been the ones pushing data speeds beyond 168 Mbps. But given AT&T's acquisition of T-Mobile and its plans for rolling out LTE, it may not want to make the investment given the fact that 2x2 MIMO is required to reach the 84 Mbps and higher speeds.--Lynnette

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