Collateral Estoppel May Bar Patentability of Substitute Claims in an IPR

In ZyXEL Communications Corp. v. UNM Rainforest Innovations, No. 22-2220 (Fed. Cir. July 22, 2024), the Federal Circuit affirmed-in-part, reversed-in-part, and remanded-in-part the PTAB’s findings regarding U.S. Patent No. 8,265,096 (the “’096 patent”).

The ’096 patent relates to methods for constructing frame structures in orthogonal frequency-division multiple access (OFDMA) systems. In an IPR proceeding, the PTAB found claims 1-4, 6, and 7 unpatentable as obvious but found claim 8 not unpatentable. It also granted UNMRI’s contingent motion to amend, substituting new claims and finding them to be nonobvious. ZyXEL appealed, and UNMR cross-appealed.

The Federal Circuit affirmed that claims 1-4, 6, and 7 were unpatentable as obvious. But it reversed the Board’s non-obviousness ruling for claim 8, holding that a prior art reference need not explicitly articulate or express why its teachings are beneficial if a POSA would recognize that their application was beneficial. The Federal Circuit affirmed the PTAB’s decision to grant the motion to amend but remanded it for the Board to evaluate whether the substitute claims (which were a combination of claims 1-4 and 6-8, which were now all held to be unpatentable) are unpatentable under collateral estoppel. On remand, the Federal Circuit indicated that the Board may also consider whether the substitute claims are unpatentable based on a new prior art combination not previously raised.