T-Mobile will likely announce its new LTE network on March 26 with a launch date probably soon after that. Now reports are surfacing that the company has been testing the network in eight U.S. cities.

The network was spotted in New York City but now it appears it is also being tested in San Jose (and surrounding areas), Seattle, Denver, Las Vegas, New Orleans, New York, San Diego and Kansas City, according to TechCrunch.

T-Mobile is currently using a HSPA+ network, which offers 3.5G speeds but T-Mobile had branded as 4G. T-Mobile had to follow AT&T and Verizon, just as Sprint did, by changing course on its 4G initiative by using a standard called WiMAX and switching to the industry 4G LTE standard, iTechPost previously reported.

The testing was discovered through data on a third-party app OpenSignal. Engineers noticed their signal analysis/mapping app was used by an unfamiliar network and began monitoring it, TechCrunch reports.

T-Mobile could be testing the LTE network in other cities using other tools, so the list may be incomplete.

OpenSignal's testing tool determines network speed and was able to get an idea of what T-Mobile's long-awaited LTE network has in store. The average performance was timed at 25 Mb/s download and 8 Mb/s upload.

At its March 26 press conference, T-Mobile will likely announce the 4G LTE network and its plans to offer unsubsidized phones, including possibly iPhone 5. Several million people are using unlocked iPhones on T-Mobile but 3G speed has limited their ability to use Visual Voicemail.

As iTechPost previously reported, the iPhone 5 release rumor would make sense, considering the 4G LTE roll-out. With T-Mobile's merger with MetroPCS approved last week by the FCC, T-Mobile may also have news about doing away with two-year contracts in lieu of non-contract plans.