In T-Mobile USA's fourth quarter 2011 earnings report, the magenta-branded carrier made official its plans to deliver LTE in 2013 on its AWS spectrum holdings, which were recently bolstered with more AWS acquired from the failed AT&T merger. In addition, the carrier will continue to deploy HSPA+ WCDMA carriers on its PCS 1900 holdings as part of its spectrum refarming efforts where possible. Some 37,000 cell sites will receive new hardware (likely new software defined radio base stations) that will make possible first HSPA+ improvements, and later the ability to light up LTE carriers when the time is right.

There has been considerable speculation about what T-Mobile's long term LTE plans would be leading up to this announcement, and the news doesn't come as a surprise for a number of reasons. In recent months, T-Mobile has been engaging in a number of practices to further its efforts to refarm PCS 1900 spectrum which it currently fills with GSM carriers. Efforts such as offering its entire "4G" collection of phones for free on contract signal the carrier's intention to get more subscribers on WCDMA, and in other markets with lots of PCS users have already reported seeing WCDMA on 1900 MHz PCS. In addition, the move will enable subscribers with unlocked iPhones in the USA a chance to get off of EDGE and onto 3G WCDMA. The absence of the iPhone is something T-Mobile identifies in their report as a "significant cause of contract deactivations," and more deployments of 1900 MHz WCDMA in conjunction with plans to offer more support for iPhone users are no coincidence. 

Lighting up WCDMA carriers on PCS 1900 will also enable T-Mobile to deploy DC-HSPA+ in some markets where it can't already. Dual-band DC-HSPA+ is a 3GPP Rel.9 feature that multiple upcoming basebands will support. It isn't completely clear just how much spectrum T-Mobile will end up with on average for LTE, but 5 MHz FDD in some markets and 10 MHz FDD in others seems like a good bet. As an aside, I would still love to see at least someone run 15 or 20 MHz FDD-LTE here in the USA. Update: During T-Mobile's "Challenger Strategy" conference call today, 10 MHz FDD-LTE on AWS was noted as the most likely target, which would bring peak LTE downstream speeds of 73 Mbps.

T-Mobile expects to reach broad deployment of LTE, with service in the vast majority of the top 50 markets and 20 MHz (10 MHz FDD) service in 75 percent of the top 25 markets. Most remaining markets will have 10 MHz (5 MHz FDD). 

The last encouraging and unstated bit of all this is that there's some chance that eventually we'll see some LTE device compatibility between AT&T and T-Mobile, who have both now announced support for LTE on AWS. 

Source: T-Mobile Earnings, Challenger Strategy