Verizon Wireless’ new LTE network may be experiencing the biggest growing pains among U.S. operators, but T-Mobile’s brief network outage Monday night showed that even an established technology like HSPA+ isn’t free from problems.

Last night T-Mobile experienced intermittent data outages in different parts of the country, which led customers to flood T-Mobile’s Twitter feed and support forums with questions and complaints. T-Mobile confirmed the outage in a tweet at 7:48 p.m. PT, and 90 minutes later it tweeted that the network problems had been resolved and service restored to normal.

T-Mobile didn’t state publicly what the cause of the outage was, but if I can hazard a guess: T-Mobile is currently engaged in a major network overhaul, switching out major portions of its GSM network for new Ericsson and Nokia Siemens Networks HSPA+ base stations. At the same time, it’s retiring portion of its current HSPA+ network in the 1700 MHz/2100 MHz (AWS) band in order to make room for its new LTE systems.

It just so happens the first phase of that network reconfiguration is scheduled to begin this month with an initial 2500 cell sites. You can’t move that much hardware around with out experiencing some problems, so we’re probably going to see several more hiccups on the T-Mo network over the next year.

T-Mobile image courtesy of Flickr user swruler9284

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• The future of mobile: a segment analysis by GigaOM Pro
• CES 2012: a recap and analysis
• Updated: Forecast: global mobile subscribers, 2010-2015