Cisco Systems, Inc. v. Tq Delta, LLC
928 F.3d 1359
Fed. Cir.2019Background
- TQ Delta owns U.S. Patent No. 8,611,404 (the ’404 patent) concerning multicarrier transmission with low-power sleep and rapid-on features.
- Cisco and Arris filed inter partes review (IPR) petitions challenging various claims; the PTAB issued final written decisions finding the challenged claims not unpatentable over prior art.
- A companion Federal Circuit opinion (No. 2018-1799) found claims 6, 11, 16, and 20 obvious; that determination mooted those claims in this appeal.
- Remaining challenged claims on appeal: claims 1–5, 7–10, 12–15, and 17–19 (the “Challenged Claims”), with claim 6 treated as illustrative.
- Central disputed term: “synchronization signal.” The PTAB construed it narrowly as a signal for clock synchronization between transmitter and receiver and excluded synchronization frames; appellants argued for a broader construction that includes frame synchronization and signals used to maintain timing between transceivers.
- The Federal Circuit vacated the PTAB’s claim construction and remanded for reconsideration under the correct, broader construction because the specification supports use of the synchronization signal for establishing or maintaining timing relationships (including frame synchronization).
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Whether the PTAB correctly construed “synchronization signal” | Cisco/Arris: term includes signals used to establish or maintain timing (including frame synchronization) between transceivers | TQ Delta/PTAB: term means a signal allowing clock synchronization and excludes a synchronization frame | Court: PTAB erred; correct broadest reasonable construction is a signal used to establish or maintain a timing relationship (includes frame synchronization); vacated and remanded |
| Whether certain claims are moot due to companion decision | Appellants: companion opinion renders claims 6,11,16,20 unpatentable, so those issues are resolved | TQ Delta: (no dispute on mootness) | Court: companion decision moots those claims; they are not at issue in this appeal |
| Whether PTAB must reassess obviousness under the proper claim construction | Appellants: PTAB’s obviousness analysis rested on incorrect construction and must be re-evaluated | PTAB/TQ Delta: prior analysis sufficient under their construction | Court: Remand required for PTAB to consider unpatentability challenges under the proper construction |
| Whether dependent claims require separate treatment | Appellants: dependent claims are not separately argued as distinct from claim 6 | TQ Delta: no separate defense presented | Court: No separate analysis needed for dependent claims; claim 6 is illustrative |
Key Cases Cited
- ArcelorMittal v. AK Steel Corp., 856 F.3d 1365 (Fed. Cir.) (case-mootness principles)
- Already, LLC v. Nike, Inc., 568 U.S. 85 (U.S.) (when a case becomes moot)
- Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir.) (claim construction principles; specification as primary guide)
- In re Packard, 751 F.3d 1307 (Fed. Cir.) (specification and claims constitute the patent for PTAB construction)
- Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898 (Fed. Cir.) (do not import limitations from preferred embodiments absent clear intent)
- Redline Detection, LLC v. Star Envirotech, Inc., 811 F.3d 435 (Fed. Cir.) (standard of review for PTAB factual findings)