Google's Android could be making arch-rival Microsoft a cool $444 million (£285 million) in patent levies, a Goldman Sachs analyst has estimated, and not much short of what it makes from its own Windows Phone OS.

The company reportedly calculated the sum by totting up the $3-$6 per handset fee it should be making having reached patent deals with a number of handset makers, including HTC and, more recently, Samsung.

It's a small sum when set against the company's estimated $75 billion in annual revenues, but it not bad pocket money considering the underwhelming sums being made by its own mobile OS, Windows phone. According to Business Insider, this will add up to $0.04 to Microsoft's earnings per share.

Only days ago, Samsung became the latest Asian handset maker to cave in and agree to cough up a slice of revenues to keep the Microsoft patent team off its back.

That leaves Motorola - recently and not coincidentally bought by Google - as the single major standout against the levy with no settlement likely anytime soon.

Microsoft will see its Windows phone revenues rise as its alliance with Nokia starts to kick in but perhaps it is just as well that it is making money from Android too; Google's OS is looking as if it will be the dominant platform in the mobile age in the way that Windows was for the now-declining PC era. Fighting this could force Microsoft to cap the sums it demands from Windows Phone partners in the short term.

Increasingly, the issue of patents looks as if it could be a deciding issue with the vendor controlling the largest number in mobile technology winning in the long run. Microsoft's deal with Nokia added a reported further 30,000 to Redmond's patent pile. What customers, networks and businesses actually prefer is looking like a secondary issue.