Patent 8355484
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
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Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
Current assignee: Cerence Operating Company
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Based on the search results and the provided "PTAB proceedings on file" block, there is no PTAB activity recorded for US Patent 8355484 at this time. The search results primarily focus on the recent patent infringement litigation filed by Cerence Operating Company against Amazon, including an ITC complaint and parallel district court actions, but do not mention any associated PTAB proceedings.
Proceedings overview
There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method review) on file for US Patent 8,355,484 as of today's date, 2026-05-29. This means all claims of the patent remain unexamined by the PTAB. This gives a defendant no specific PTAB-based claim invalidation to leverage.
Strategic summary
All claims of US Patent 8,355,484 are currently UNTESTED by the Patent Trial and Appeal Board. The patent has not been subjected to any IPR, PGR, or CBM proceedings. This implies that no claims have been canceled or sustained through PTAB trials.
Regarding the estoppel landscape, since no PTAB proceedings have occurred, there are no estoppel bars under 35 U.S.C. § 315(e)(2) for any potential petitioner. All prior-art grounds that could be raised under § 102 (novelty) or § 103 (non-obviousness) based on patents or printed publications are still available for a new PTAB challenge.
There is no discernible pattern signal from PTAB filings, as there are none. The current owner, Cerence Operating Company, has recently initiated patent infringement litigation against Amazon, indicating active assertion of the patent.
Recommended next steps
Since no PTAB activity exists for US Patent 8,355,484, a defendant facing assertion of this patent should consider initiating an Inter Partes Review (IPR) to challenge the patentability of the claims. This could be a strategic move given the ongoing district court and ITC litigation. IPRs can be a faster and less expensive route to challenge patent validity compared to district court litigation, with a lower evidentiary burden (preponderance of the evidence vs. clear and convincing evidence). The patent's priority date of January 8, 2007, means it would be subject to AIA IPR rules. IPRs can be filed after 9 months of patent grant, and apply to patents issued before, on, or after September 16, 2012.
Generated 5/29/2026, 9:04:01 PM