Google has many services and products it gives away for free. They got into this market because they thought the iPhone and other phone OSes were too closed. So they created an open software approach. Here is a blurb from Wikipedia about license
Licensing
With the exception of brief update periods, Android has been available under a free software/open source license since October, 21 2008. Google published the entire source code (including network and telephony stacks)<36> under an Apache License.<37> Google also keeps the reviewed issues list publicly open for anyone to see and comment.<38>
Even though the software is open-source, device manufacturers cannot use Google's Android trademark unless Google certifies that the device complies with their Compatibility Definition Document (CDD). Devices must also meet this definition to be eligible to license Google's closed-source applications, including the Android Market.<39>
In September 2010, Skyhook Wireless filed a lawsuit against Google in which they alleged that Google had used the compatibility document to block Skyhook's mobile positioning service (XPS) from Motorola's Android mobile devices.<40> In December 2010 a judge denied Skyhook's motion for preliminary injunction, saying that Google had not closed off the possibility of accepting a revised version of Skyhook's XPS service, and that Motorola had terminated their contract with Skyhook because Skyhook wanted to disable Google's location data collection functions on Motorola's devices, which would have violated Motorola's obligations to Google and its carriers.<41>
In early 2011 Google chose to temporarily withhold the source code to the tablet-only Honeycomb release, which called into question the "open-ness" of this Android release.<42> The reason, according to Andy Rubin in an official Android blog post, was because Honeycomb was rushed for production of the Motorola Xoom,<43> and they didn't want third parties creating a "really bad user experience" by attempting to put onto smartphones a version of Android intended for tablets.<44> Google later confirmed that the Honeycomb source code would not be released until after it was merged with the Gingerbread release in Ice Cream Sandwich.<45>
Oh, and most of those patents weren't that relevant. Many were social app type patents. And Google does not sell the hardware, so none of those were relevant to Google.