Android-based phone makers are at a stake of paying a large sum of money to Microsoft and Oracle for patent infringement, giving a chance for Apple’s iOS and iPhone to widen the gap in the rivalry mobile OS competition.

Unlike Apple who developed their own operating system for iPhone, other major rivalry smartphone companies – including Samsung, Motorola, and HTC – have taken  advantage of the so-called-free Android OS on their phones.

However, partnering with Android may not have been free after all as a serious repercussion is about to come.

Both Microsoft and Oracle are going after Android-based smartphone makers and ask them to pay per device sold, putting a heavy pressure on the companies.

Oracle, who is already in a legal battle against Google claiming that Android has infringed Java copyright, is now directly approaching the smartphone manufacturers, according to Jonathan Goldberg of Deutsch Bank’s report to CNET. The report says Oracle is offering an early adopters program, which will require the smartphone makers to pay around $15 to $20 per device to license the technology that Oracle claims its own patents.

Goldberg told CNET that no one has signed this program at the moment.

Microsoft is also putting a strain on Android users.

“It’s not like Android’s free. Android has a patent fee. You do have to license patents,” said the Microsoft CEO Steve Ballmer in an interview with The Wall Street Journal.

HTC has already agreed a deal with Microsoft, paying $5 per device sold. Motorola has decided to fight against Microsoft in a legal battle. Microsoft has recently requested $15 per device to Samsung, and the South Korean company is reportedly in a negotiation process of lowering the cost, as the Guardian reports.

It is unfortunate for Google and Android to have lost the Nortel patents, a collection of over 6,000 mobile patents, in an auction last week against a team of rivals comprising of Microsoft, Sony, RIM, EMC, Ericsson, and later joined Apple. Obtaining the patents, according to the Washington Post, could have been the last saving factor for Android.

The situation for Android-based phone and its makers seem gloomy at the moment. But could the IT-giant able to bring back hope for the mobile companies who were loyal to Android? Or is it going to fall behind in a race against Apple’s iPhone and iOS?