Samsung filed a countersuit to Apple's patent claim, accusing the Cupertino, Calif.-based technology giant of infringing on 10 patents, most of which relate to smartphone software and hardware.

Apple sued Samsung on April 16, claiming that Samsung's smartphones, including the Galaxy S 4G, Nexus S and Epic 4G, were copies of the Apple iPhone design as well as its technology. Much of that suit centers on the similarities between the designs of Samsung Galaxy S and iPhone 4.

Samsung fired back with its own countersuits in Germany, Japan and South Korea. Those suits center on patents related to reducing power use during data transmission, reducing data transmission errors on 3G networks, and wireless data communication.

The 10 patents Samsung cites in its latest complaint are broadly similar. They are for technologies that control the ways a mobile phone transmits and receives data, the method by which the phone displays incoming images and the user interface.

The patent battles between Samsung and Apple are a bit unusual, says Florian Mueller, an intellectual property consultant in Germany. Samsung is a major supplier of components to Apple, and the lawsuit could complicate that business relationship.

Unlike the Apple complaint, Samsung's doesn't address any visual or design similarities between its phones and Apple's iPhone-it covers technology patents only.

Apple, meanwhile, is claiming that Samsung lifted significant portions of the iPhone's user interface and the iPhone's trade dress, a term used to describe the shape of the device itself. Like the iPod and iPad, Apple says, the Galaxy Tab features a rectangular design with rounded corners and a black border. Rows of icons also play a significant role in the device's design. Apple's suit also cites Samsung's Galaxy Tab, a major competitor to the iPad tablet, as a major reason for the suit.

Apple filed a similar suit against both HTC and Nokia. Both are still pending. The various smartphone makers and technology companies -- including Apple, Nokia, Research in Motion, Motorola and even Kodak -- are all enmeshed in a web of intellectual property lawsuits.

In the U.S. court system, claims of infringement in other countries don't have as much value as precedent as a case in the U.S. The lawyers can only cite the cases and hope that the judge takes it into consideration. That is one reason Samsung chose to countersue in the U.S. to begin with and supplement it with suits overseas. Filing suits in overseas jurisdictions is also an effective way of driving up the cost of litigation for the other party.

If either side loses, it could cost the company tens of millions, and possibly hundreds of millions of dollars in damages. The costs could go even higher if damage awards are given out in several countries.

The full text of Samsung's patent suit is here.