T-Mobile US (NYSE:TMUS) said 92 percent of MetroPCS' customers on its legacy CDMA network in Boston, Hartford, Conn., and Las Vegas moved onto T-Mobile's GSM/HSPA+/LTE network after T-Mobile shut off MetroPCS CDMA service in those markets. The carrier next plans to shut down MetroPCS' CDMA network in Philadelphia sometime later this year.

To move the customers, T-Mobile starting in April notified MetroPCS customers in Boston, Hartford and Las Vegas that they should move to T-Mobile's GSM-based network, and trade in their old CDMA phone for a new GSM one, in most cases at little to no cost. In April, T-Mobile warned those customers that their CDMA phones would no longer work after July 1.

"We've worked hard to make it easy, and to date, close to 92 percent of customers in those markets are now running on the new, faster 4G LTE network," T-Mobile said in a statement to FierceWireless.

On July 7, T-Mobile started to shut down the CDMA network in Boston, Hartford, and Las Vegas. T-Mobile is refarming the AWS spectrum in these markets to create wider spectrum channels and more capacity in its LTE network. Indeed, in mid-July T-Mobile said it launched LTE service in Las Vegas on "Wideband" 15x15 MHz channels, making Las Vegas one of 17 markets where T-Mobile is touting more capacity and faster speeds.

"However, for the handful of customers who have not yet moved over, their phones deactivated on or shortly after July 7, except for 911 emergency services and the 611 MetroPCS customer care line," T-Mobile said. "We prepared these customers for the switch, having sent messages outlining details of the transition via SMS and voicemail in both English and Spanish, as well as posting information in our stores, on our website, and through customer care lines, encouraging them to make the switch. We are ready and able to help these customers when they're ready to make the move and intend to continue our trade-in program until all customers have completed the migration process."

T-Mobile said it is "taking a very deliberate approach to repurposing the MetroPCS spectrum, going market by market and learning as we go, making things easier and smoother for customers in the future." For example, the carrier noted that it discovered a situation in Boston, Hartford, and Las Vegas where Samsung Galaxy S3 owners didn't have a comparable handset upgrade option, so the carrier increased the amount of their trade-in value by $100 (to $299) to ensure they could get a smartphone like the LG Optimus F6 and get a credit to their account.

"As we expand the migration effort to future markets, we will continue to communicate with customers months in advance in order to ensure a seamless experience," the carrier said.

Earlier this year, T-Mobile said the migration of customers off the legacy MetroPCS CDMA network was happening faster than it had anticipated. The company identified the CDMA networks in Philadelphia, Las Vegas and Boston as ones that would be shut off by the end of this year, a year earlier than expected.

The main reason T-Mobile is shutting down MetroPCS' CDMA network is to save on the cost of operating the network and to repurpose the spectrum for LTE. The "Wideband LTE" moniker is the operator's marketing term for spectrum deployments of at least 15x15 MHz. T-Mobile offers Wideband LTE in Atlanta, Ga.; Birmingham, Ala.; Columbus, Ohio; Dallas; Detroit; Honolulu; Houston; Jacksonville, Fla.; Las Vegas; Los Angeles; Minneapolis; Mobile, Ala.; Orlando, Fla.; Portland, Ore.; Seattle; Tampa, Fla.; and parts of upstate New York.

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