Google on Wednesday confirmed that it has added more IBM patents to its technology arsenal as smartphone rivals increasingly battle in courts over innovations.

Google bought 188 patents and 29 patent applications related to mobile phones from IBM but did not disclose how much it paid.

Last year, IBM sold Google 2,000 or so patents ranging from mobile software to computer hardware and processors.

Google has been strengthening its patent portfolio as the fight for dominance in the booming smartphone market increasingly involves lawsuits claiming infringement of patented technology.

The California Internet powerhouse behind Android mobile device software last year transferred a set of patents to smartphone titan HTC Corp. to help the Taiwan-based company in an intellectual property clash with iPhone maker Apple.

Technology giants have taken to routinely pounding one another with patent lawsuits. Apple has accused HTC and other smartphone makers using Google's Android mobile operating system of infringing on Apple-held patents.

Some of the patents that HTC got from Google had belonged to Motorola Mobility, which Google is buying for $12.5 billion in cash.

Motorola Mobility's trove of patents was a key motivation for Google, which is keen to defend Android.

"Our acquisition of Motorola will increase competition by strengthening Google's patent portfolio, which will enable us to better protect Android from anti-competitive threats from Microsoft, Apple and other companies," Google chief executive Larry Page said when the Motorola Mobility buy was announced.

Motorola Mobility chief executive Sanjay Jha told financial analysts the US maker of smartphones and touchscreen tablet computers has over 17,000 issued patents and another 7,500 pending.