T-Mobile USA was sued today by a company called On Track Innovations, which claims that T-Mobile's smartphones with NFC technology infringe one of its patents. OTI's been around since 1990 and has a long history developing smart card systems, which is why the single patent in the lawsuit may not be quite so easy to win with in court: it narrowly covers a "data transaction card" with fixed contacts on it in addition to working in a contactless mode. That doesn't appear to describe either the Samsung Galaxy S II or the Nexus S — T-Mobile's only NFC smartphones — but we have yet to see OTI's complaint and how the company's lawyers have made the argument. Then again, OTI says it's pursuing an "ongoing strategy to leverage its IP assets," so in the end this is less about patents and more about cash. We'll see how hard T-Mobile decides to fight back.