Google headquarters must be all high-fives today. Just hours after the European Commission cleared the company’s proposed acquisition of Motorola, the U.S. Department of Justice has given its approval on the deal as well.

“The division concluded that the specific transactions at issue are not likely to significantly change existing market dynamics,” the Department of Justice said in a press release today that concerned Google’s Motorola acquisition and its approval of the Nortel and Novell patent sales to other major tech companies.

The U.S. and EU had been looking closely at the Google acquisition of Motorola because of possible antitrust issues. There were apparent concerns that Motorola could be given unfair advantage when it came to Android mobile operating system that is developed by Google and embedded in Motorola phones and tablets.

Google deflected those concerns by saying that it is in the company’s best interest to maintain the Android ecosystem and not give Motorola advantages over mobile device manufacturers such as Samsung, HTC, and LG.

The primary reason Google said it wants Motorola is to own its patents, which will help Google better defend Android from lawsuits. Motorola Mobility has some 17,000 patents, and it has another several thousand patents pending approval. That will make for one heck of a shield when other companies like Microsoft, Apple, and Oracle try to attack Android and its manufacturing partners.

In a related note, the Department of Justice’s press release about Google and Motorola also announced that it had approved a deal for a consortium including Microsoft, Apple, and RIM to buy Nortel’s patent portfolio. The release also states that Apple has won approval to buy some of Novell’s patents.

“After a thorough review of the proposed transactions, the Antitrust Division has determined that each acquisition is unlikely to substantially lessen competition and has closed these three investigations,” the DOJ said. “In all of the transactions, the division conducted an in-depth analysis into the potential ability and incentives of the acquiring firms to use the patents they proposed acquiring to foreclose competitors.”

Google logo: Flickr/Robert Scoble