A legal battle between Apple Inc and Nokia Corp over patent infringement is likely to last for more than a year, said Bill Merritt, the head of mobile licensing firm InterDigital.

Nokia dominates the global handset market, but it has lost ground to smartphone entrants like Apple, which has become one of the top handset vendors. "It's not a David versus Goliath story, these are two Goliaths," Merritt said.

Nokia filed suit in the United States last week, saying Apple had infringed 10 patents in technologies like wireless data transfer, a key factor in the success of iPhone. The suit accused Apple of trying to hitch a "free ride" on Nokia's technology investment.

In its form 10-K annual report filed on Tuesday, Apple said it "intends to defend the case vigorously."

The patents cover wireless data, speech coding, security and encryption and are infringed by all iPhone models shipped since the iPhone was introduced in 2007, Nokia said.

"It's the first card to be played, there's a lot more cards left. How this plays out will largely depend on Apple's response," Merritt told Reuters in an interview, adding the case was likely to continue for a couple of years.

"I'd be very surprised if anything gets solved in the short term. It's at least a year before some clarity," he said.

He said if Apple decides to just defend itself, or to countersue, the case would likely last two to three years, but if it takes the case to the US International Trade Commission, the decision would come somewhat faster.

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