The week is ending with a storm of wireless patent activity. Google has filed a European suit accusing Microsoft and Nokia of hiding behind patent trolls, and has also scored the latest victory in its court battle with Oracle. The US International Trade Commission's hearings of Apple's allegations against Samsung have begun and another US agency, the Fair Trade Commission, has echoed recent European Commission concerns about the potential misuse of patents policies by mobile vendors.

Google's latest action is the first time it has taken direct aim at Microsoft, and the timing perhaps reflects its new IPR confidence in the wake of finalizing its acquisition of patent-rich Motorola Mobility. Before this, the search giant has supported Android partners in their defences against Apple and Microsoft attacks but has rarely acted directly. Microsoft, by contrast, has been very aggressive in asserting its patent rights in Android, and has signed licensing deals with most of the major OEMs - but not with Motorola Mobility. The new Google unit remains locked in combat with the Windows giant, and that will only intensify now.

Google is expected to unleash several lawsuits from its new position of strength, but it has started with an antitrust complaint with the European Commission, alleging that the Microsoft-Nokia axis is using patents to thwart competition. Specifically, it is focusing on

a transfer of about 2,000 patents and applications, which Nokia and Microsoft made last year to Canadian patent aggregator Mosaid Technologies.

Some of these are essential to wireless standards, which means they fall under European 'Frand' (fair reasonable and non-discriminatory) licensing rules. That limits their owner's flexibility in how they charge for the patents, and the assets cannot be withheld from a licensee or used to disadvantage a rival. Google's contention is that Microsoft and its premier handset ally are avoiding their obligations by putting the patents in the hands of a third party, and a litigious one at that - even though Microsoft has publicly pledged, most recently during the EU examination of the Google-Motorola deal, that it would not use essential IPR to block rivals from competing.

"Nokia and Microsoft are colluding to raise the costs of mobile devices for consumers, creating patent trolls that sidestep promises both companies have made," said Google in a statement. "They should be held accountable, and we hope our complaint spurs others to look into these practices."

Frand issues have been at the heart of several of the ongoing handset IPR disputes, especially those involving Apple and its Android rivals - Apple rarely cites standards essential technologies, while the power of combatants like Samsung and Motorola is heavily based on such patents. Samsung and Motorola are the subjects of preliminary EU probes regarding possible Frand infringements and other abuses of IPR strength. The Motorola investigation was prompted by complaints from Microsoft and Apple.