T-Mobile has officially launched its 4G LTE network today with service in Baltimore, Houston, Kansas City, Las Vegas, Phoenix, San Jose, and Washington DC. The carrier expects to deliver LTE to 100 million people by the middle of 2013 doubling that to 200 million customers nationwide by year's end. Customers will be able to use the new faster service with the carrier's new rate plans, which initially went live this past weekend.

T-Mobile has a long way to go to catch up to the other major carriers when it comes to LTE coverage. Both Verizon Wireless and AT&T have been rolling out LTE service for a couple of years now, and Sprint launched its LTE network last summer. T-Mobile will be using its purchase of MetroPCS to help it launch LTE on the AWS frequencies, in addition to the spectrum it gained from AT&T's failed buyout in 2012. The carrier plans to have 200 million people covered by LTE by the end of this year.