Wireless research firm OpenSignal Inc. has identified T-Mobile USA 4G services in nine cities, providing an average download speed of 25 Mbit/s, ahead of the wireless operator's imminent official launch of LTE-based services. (The launch is expected on March 26 -- see T-Mobile's LTE Advance: What's Happening.) OpenSignal states in its report that users of its app -- including "many network engineers" -- have detected T-Mobile's LTE signal in Seattle, Denver, Las Vegas, Kansas City, New Orleans, New York, San Diego, San Jose and San Francisco ("Bay Area"). T-Mobile has only revealed Kansas City and Las Vegas as launch cities so far. Other T-Mobile subscribers have reported seeing signals in the Baltimore and Washington D.C areas too, as well as parts of Texas.T-Mobile has to launch big with 4G services to meet its targets: The operator wants to cover 100 million potential customers in the U.S. with the new technology by the middle of 2013.The operator is the first in the U.S. to deploy a network based on Release 10 of the 3GPP's LTE specifications. While this release incorporates the specifications for LTE-Advanced -- the next evolutionary step of 4G -- T-Mobile's network is best described as "LTE-Advanced-ready," as the user device hardware to receive LTE-Advanced services is not yet commercially available. (See Why You Should Care About LTE-Advanced (Eventually).)Nonetheless, OpenSignal's findings of average 25Mbit/s downloads in the test cities is consistent with Release 10 LTE deployed in 2x5MHz channels. In all, the report says the speed test app "observed a respectable 25Mb/s average download speed, an 8Mb/s average upload speed and an average latency of 40ms." OpenSignal also notes that this is "early days" for T-Mobile and that real-world speeds will be different. The current results are "based on a small sample size, there's no other load on the network and the tests that gives us this data were likely carried out close to cell sites with good signal," OpenSignal notes. T-Mobile does already have good 3G speeds to fall back on when users are outside of LTE coverage areas. In its recent report, RootMetrics notes that T-Mobile's "HSPA+ 42" network (offering speeds up to 42 Mbit/s) is providing average downloads of 7.3 Mbit/s across 77 markets tested.Samsung Corp., meanwhile, is well represented on the device side of T-Mobile’s new LTE network. The imminent service launch was revealed when T-Mobile issued an over-the-air update for the Galaxy Note II. "We've also seen them use an unreleased Galaxy S IV to test their LTE network," OpenSignal notes.The firm also detected Samsung S II HD and unlocked AT&T S III smartphones on the network, all of which suggests that Samsung will be a key device supplier for T-Mobile’s nascent LTE network. — Dan Jones, Site Editor, Light Reading Mobile