Arbitron has filed a patent-infringement complaint against The Media Audit and its European partner, Ipsos, alleging that The Media Audit's smart-cell-phone radio ratings technology infringes on its portable people meter technology.

Arbitron is seeking a permanent injunction against its rival, and is asking for compensatory damages, writes Adweek (via MediaBuyerPlanner).

The Media Audit first emerged as a possible competitor to Arbitron's portable people meter ratings service when Clear Channel Radio requested proposals for a new electronic ratings measurement system. Arbitron and The Media Audit/Ipsos were the finalists, and the Clear Channel committee, made up of representatives from radio groups and agencies, has yet to make a final decision.

Clear Channel, however, has been loath to renew a long-term deal with Arbitron based on its portable people meter without any competition in the market, according to MediaPost. However, about a third of radio broadcasters, including CBS Radio, have signed with Arbitron., and many industry executives and analysts expect Clear Channel to do so as well in the coming months.

In related news, a TV ratings startup erinMedia received a ruling from the U.S. Patent and Trademark Office accepting two of the company's patent claims tied to its system for measuring TV audiences via digital set-top devices.