InterDigital Communications, LLC. v. International Trade Commission

The differentiation doctrine presumption is particularly strong in cases where a limitation is the sole differentiation between claims and one party is asserting a dependent claim on an independent claim.

Opinion (Bryson): InterDigital Communications, LCC (“IDC”) appealed an International Trade Commission (“ITC”) ruling that Nokia did not infringe its patents. The patent uses the terms in two separate claims; in claim one “code” was used to describe the system used by cell phones to locate a cell phone tower (“tower”) over a multi-user frequency, whereas in claim five “code” as described in claim one was a “spreading code” transmitted by the phone to connect discreetly to a tower for data transmission. An ITC administrative judge determined that the term “code” should be limited to the definition in claim five; thus, the administrative judge imposed a dependent definition on an independent claim. The differentiation doctrine imposed a presumption that a dependent claim could not be read into an independent claim without “strong contrary” evidence. Here, the administrative judge’s interpretation rendered claim five superfluous to the patent, reasoning that since the code refers to a secondary system which uses “spreading codes” and does not identify non-spreading codes that all codes must be “spreading codes.” However, the Court of Appeals found that the simple non-identification of codes was not “strong contrary” evidence that only spreading codes were used. Furthermore, the Court of Appeals found that IDC did not intend to limit all codes to data carrying codes, and implicated such differences in other claims. Thusly, the ITC’s ruling was REVERSED AND REMANDED.