AT&T beats Cheetah patent claim with the ‘grandparent’ principle

US telecoms giant AT&T has fought off a patent infringement claim from optical products developer Cheetah OMNI, after the Federal Circuit confirmed that a license covering a patent’s ‘grandparent’ also covers subsequent descending patents.

Cheetah, which owns US Patent 7,522,836 (related to optical communication networks), had asserted at the District Court for the Northern District of Texas, that AT&T had infringed the patent by “making, using, offering for sale, selling, or importing its fiber equipment and services”.

In response, Ciena Communications, a telecom networks, products and services provider, and also a named defendant, moved to intervene in the suit because it manufactures and supplies certain components for AT&T’s fiber optic systems, the components that formed the basis of some of Cheetah’s infringement allegations.

The Texan court granted Ciena’s motion to intervene, and Ciena and AT&T then moved for summary judgment that Cheetah’s infringement claim was barred by agreements settling previous litigation over the ‘836 patent’s ‘grandparent’, brought by Cheetah against both Ciena and Fujitsu Network.

In 2011, Cheetah brought a lawsuit against Ciena and Fujitsu, accusing them of using certain Reconfigurable Optical Add/Drop Multiplexer (ROADM) products that infringed its US Patent 7,339,714. ROADM products add the ability to remotely alter data transfer methods.

Cheetah had settled the case with both Ciena and Fujitsu, executing two separate deals with each party, namely a covenant not to sue and a license.

Cheetah granted to Ciena “a perpetual, irrevocable, worldwide, nonexclusive, fully paid-up license under the Licensed Patents to make, have made (directly or indirectly and solely for Ciena or its affiliates), use, offer to sell, sell, and import and export the licensed products”.

Hence, the US Court of Appeals for the Federal Circuit found that “AT&T’s fiber optic products were covered by an earlier license to a grandparent patent covering the same invention between Cheetah and AT&T’s supplier”.

“Because the licenses extend to both the ’836 patent and the AT&T products accused in this litigation, the district court properly granted summary judgment for AT&T and Ciena and dismissed the infringement suit,” said the appeals court.

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