By AppleInsider Staff

Published: 06:55 PM EST (03:55 PM PST)

Google purchased another round of patents from IBM in the last week of 2011, adding 217 filings as the search giant looks to strengthen its existing IP portfolio to help protect itself in an increasingly litigious tech industry.

A report on Tuesday revealed that the United States Patent and Trademark Office officially recorded Google's acquisition of 188 granted patents and 29 published pending applications from IBM in its patent assignment database on Dec. 30, 2011, according to blog SEO by the Sea.

The patents, which were effectively assigned to Google on Dec. 28, 2011, cover a variety of topics pertinent to the company's internet business including blade servers, server load balancing, email administration and network performance.

Also found in the batch of intellectual property are patents useful to Google's Android smartphone platform, like portable OS updating, transferring of web applications between devices, voice based keyword searching and a computer phone patent.

The keyword searching patent is of particular interest as Apple's Siri digital assistant is seen as a key feature of the company's iPhone 4S, with at least one market analyst saying that it was one of the main drivers of November sales for the new handset. Google is rumored to be working on a Siri competitor for its Android OS, naming the project "Majel" after Star Trek's on-board computer.

Google has been on an IBM patent buying spree over the last year, with a July 2011 acquisition of 1,030 filings being followed by purchases of 1,022 filings and 41 filings in August and September, respectively.

The financials of the patent buy has yet to be revealed, and both Google and IBM don't normally disclose the details of such transactions.