The 4G LTE CellSpot is a like a mini-tower for your house or office. (Photo11: T-Mobile)

NEW YORK—Your cellphone coverage is pretty good in the neighborhoods where you live and work, but securing a decent signal inside your house has proved to be a challenge.

On Monday, T-Mobile announced T-Mobile 4G LTE CellSpot, an 8.5-inch tall and 8.5-inch wide box which plugs into your Internet router and which the company claims can provide an average of 3,000 square feet of full-bar LTE coverage indoors. Based on "femtocell" or "small cell" technology, T-Mobile says this is the first-ever 4G LTE mini-tower available from a U.S. wireless provider.

LTE (Long Term Evolution) is the prevailing 4th generation of speedy wireless. T-Mobile's solution is like putting a tiny cell phone tower in the home to improve coverage in the basement or other areas where network coverage might be shaky.

T-Mobile is giving CellSpot to its post-paid customers for free, though you'll have to leave a refundable $25 deposit, and remain a T-Mobile customer. Post-paid refers to the lucrative segment of customers who pay their wireless bills each month.

The low-power box becomes available on Wednesday. If you're a qualifying customer, you can request CellSpot in a T-Mobile store but the company won't have them in stock and is instead shipping out units.

T-Mobile is also pushing the benefit to its small business customers, since the 4G LTE CellSpot supports up to 16 calls at one time and works with any 3G, 4G or LTE device that is compatible with T-Mobile's network. But you'll need a T-Mobile phone to tap into the signal.

It's a "huge feat of engineering," T-Mobile CEO John Legere said in a statement.

Under Legere, T-Mobile has been building out and bolstering its 4G LTE network coverage, while attempting to also improve the company's reputation. Its 4G network now reaches more than 300 million people in the U.S., which T-Mobile claims puts the carrier on par with Verizon Wireless and AT&T. Still, the 4G LTE CellSpot could help provide coverage to consumers in less populated areas , where T-Mobile's coverage may not be as strong as its rivals.

This isn't the first time T-Mobile has tried to bolster indoor coverage.

In September of last year, T-Mobile unveiled a CellSpot Wi-Fi router that lets customers make Wi-Fi calls and text in areas beyond cell coverage. More than 1 million of the routers are currently in circulation; T-Mobile customers are making more than 11 million Wi-Fi calls daily, the company says. T-Mobile also offers customers a 4G LTE CellSpot Signal Booster.

That raises the question of where the new 4G LTE CellSpot box fits in, especially if you can already use a router to make Wi-Fi calls.

T-Mobile says that LTE is often faster and more reliable than Wi-Fi, and that the new box is compatible with the latest network technologies, including HD Calling, VoLTE (Voice over LTE), advanced messaging, and video calling. And once installed, T-Mobile's chief operating officer Mike Sievert said in an interview that "customers have to do absolutely nothing to make it work."

Today's announcement comes ahead of T-Mobile's next big "Un-carrier" promotional event, scheduled to take place in Los Angeles on Nov 10. Though T-Mobile hasn't said what next week will bring, the speculation is that the company might let you use popular streaming video services--perhaps, HBO, Hulu, Netflix, and so on—without having it count against your monthly data usage. T-Mobile already does this with many popular music services. Sievert wouldn't spill the beans ahead of time.

Email: ebaig@usatoday.com; Follow USA TODAY personal tech columnist @edbaig on Twitter

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