Microsoft's strategy of demanding patent license fees from major Android device makers has been resoundingly successful in recent months, but that doesn't mean it's not controversial: the Wall Street Journal says Barnes & Noble has asked the Justice Department for an antitrust investigation into Redmond's attempts to "kill off" Android devices from smaller players with license fees and lawsuits. B&N told the government over the summer that "Microsoft's willingness to bully small players with expensive litigation raises a substantial barrier to entry" because only big companies can afford to pay the license fees. Unfortunately, we don't know how much Microsoft asks in fees, so we can't really evaluate that claim, but it's obviously more than Barnes & Noble was willing to spend — and when B&N refused to pay, the money was enough for Microsoft to file a lawsuit.

For its part, Microsoft says that it's had to pay patent licenses for Windows, and that it's happy to license its intellectual property to Android makers, Barnes & Noble included. That's very polite, but if Microsoft's real plan is to make Android more expensive for OEMs to use than Windows and Windows Phone, the Justice Department might well take action.