T-Mobile has become the kid who writes his term paper the night before it's due. For months now, the No. 4 wireless carrier has been insisting that it will cover 100 million Americans with its new LTE network by "midyear," and 200 million by the end of the year.

As I'm writing this at noon on June 28, that means they have about 60 hours to cover 76 million people.

The company announced its first seven LTE markets in late March: Houston, Kansas City, Las Vegas, Phoenix, San Jose, Baltimore, and Washington DC. Since then, nothing. Obviously, T-Mobile's network team hasn't been sleeping on the job. In our Fastest Mobile Networks 2013 tests, we saw glimpses of their LTE network in Tucson, San Francisco, New York City, and Seattle.

If T-Mobile is holding back until it has comprehensive coverage across metro areas, that's probably a good strategy. First Clearwire frustrated users with a WiMAX network full of holes, and now Sprint is getting mixed reviews for letting its users on board an LTE network that's clearly still in progress. Fortunately for T-Mobile, it has its fast HSPA+ network to fall back on, although as we found out in our network testing, it's not quite as fast as it appears because of slow time-to-first-byte results.

Still, though, I'm edgy. T-Mobile is the last major carrier to install LTE, and its LTE network has been trailing a bit behind predictions. Back at CES on Jan. 8, T-Mobile's CEO said LTE was coming "in another week or two." It came on March 26. Meanwhile, Verizon Wireless has covered pretty much the whole country.

This isn't just about speed. Increased LTE coverage will help T-Mobile absorb MetroPCS and keep that carrier's more than 9 million subscribers. Metro's competitors, most notably Boost, are running ads targeting Metro customers who feel uncertain about the effects of the merger. Since MetroPCS LTE phones will be able to access T-Mobile's LTE network, they'll see a dramatic jump in speeds when they get onto T-Mobile's system. That's a reason to stay.

I contacted T-Mobile for this story and they didn't have a new update, but I talk to T-Mobile every few days, and the last time I asked them about this deadline, they just smiled and told me to stay tuned.

T-Mobile is holding a press event on July 10, a full week and a half after its supposed deadline. Is it waiting to announce its LTE rollout, or will that event be about something entirely different? We'll see this weekend.

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