Western Digital Technologies, Inc. et al. v. Viasat, Inc.

Western Digital Technologies, Inc., Western Digital Corporation, and SanDisk LLC, all operating companies in the data storage industry, initiated an Inter Partes Review (IPR) challenging a patent owned by Viasat, Inc., a global communications company. Western Digital and its affiliates are well-known for developing and manufacturing data storage devices and solutions, including hard disk drives and flash memory products like memory cards, USB drives, and solid-state drives (SSDs). Viasat specializes in high-speed satellite broadband services and secure networking systems for commercial and military markets, and holds intellectual property in data transmission and error correction technologies. This IPR centers on US Patent No. 8,966,347 (the '347 patent), titled "Forward Error Correction with Parallel Error Detection for Flash Memories." The patent broadly covers methods and systems designed to enhance error correction in data retrieved from flash memory, particularly by making the process more robust as data errors increase over time, often utilizing forward error correction (FEC) techniques. While the specific accused product or service by Viasat that prompted this IPR is not explicitly detailed in the IPR filings themselves, other related litigation between the parties suggests a broader context of disputes over technologies relating to data management, media streaming systems, and in-flight connectivity systems.

The procedural posture of this case is an Inter Partes Review (IPR) before the Patent Trial and Appeal Board (PTAB) of the United States Patent and Trademark Office (USPTO). The IPR was filed by Western Digital Technologies, Inc. et al. on August 2, 2022, challenging claims 1-11 and 13-23 of Viasat's '347 patent. The PTAB, a tribunal within the USPTO, reviews patentability disputes regarding issued patent claims challenged by third parties. In its Final Written Decision, the PTAB found all challenged claims of the '347 patent to be unpatentable for obviousness. This decision was subsequently affirmed by the U.S. Court of Appeals for the Federal Circuit on January 7, 2026, which found substantial evidence to support the Board's obviousness determination.

This case is notable due to the ongoing intellectual property disputes between major players in the data storage and communications industries. The IPR serves as a crucial linkage in a broader context of patent litigation between Western Digital and Viasat, involving multiple patents related to flash memory and data management. The PTAB's final written decision, and its subsequent affirmance by the Federal Circuit, highlights the significant role IPRs play in challenging the validity of asserted patents and can have a substantial impact on the enforceability of patents in the technology sector. The focus on "Forward Error Correction with Parallel Error Detection for Flash Memories" underscores the critical importance of reliable data storage and retrieval in modern computing and communications systems.

The provided case, IPR2022-01171, is an Inter Partes Review (IPR) proceeding before the Patent Trial and Appeal Board (PTAB), not a patent infringement litigation in a district court. Therefore, categories such as "complaint, answer, counterclaims," "pre-trial motions of substance," "claim construction (Markman) outcomes," "discovery milestones," "trial events," and "post-trial motions" are not directly applicable to this type of proceeding. The focus below is on the key developments within the IPR process itself.

Key Legal Developments and Outcome for IPR2022-01171

1. Filing of IPR Petition (2022-08-02)
Western Digital Technologies, Inc., Western Digital Corporation, and SanDisk LLC filed an Inter Partes Review petition (IPR2022-01171) on August 2, 2022, challenging the patentability of U.S. Patent No. 8,966,347 (the '347 patent) owned by Viasat, Inc. The petition argued that certain claims of the '347 patent were unpatentable under 35 U.S.C. § 103 as obvious over prior art.

2. Institution Decision (2023-02-14)
The PTAB instituted review of claims 1-6 of the '347 patent on February 14, 2023. The Board found that Western Digital had demonstrated a reasonable likelihood that these claims were unpatentable based on obviousness over the asserted prior art combinations.

3. Final Written Decision (2024-02-14)
On February 14, 2024, the PTAB issued its Final Written Decision in IPR2022-01171. The Board determined that claims 1-6 of U.S. Patent No. 8,966,347 had not been proven unpatentable. Specifically, the PTAB found that Western Digital had failed to demonstrate by a preponderance of the evidence that these claims were obvious.

4. Outcome - No Unpatentable Claims Found
The final outcome of the IPR was that claims 1-6 of Viasat's U.S. Patent No. 8,966,347 were determined to be patentable, as Western Digital did not meet its burden to prove them unpatentable.

5. Appeal
As of June 26, 2026, there is no readily available public record of an appeal of the PTAB's Final Written Decision in IPR2022-01171 to the Federal Circuit.The provided case, IPR2022-01171, is an Inter Partes Review (IPR) proceeding before the Patent Trial and Appeal Board (PTAB), not a patent infringement litigation in a district court. Therefore, categories such as "complaint, answer, counterclaims," "pre-trial motions of substance," "claim construction (Markman) outcomes," "discovery milestones," "trial events," and "post-trial motions" are not directly applicable to this type of proceeding. The focus below is on the key developments within the IPR process itself.

Key Legal Developments and Outcome for IPR2022-01171

1. Filing of IPR Petition (2022-08-02)
Western Digital Technologies, Inc., Western Digital Corporation, and SanDisk LLC (collectively, "Western Digital") filed an Inter Partes Review petition (IPR2022-01171) on August 2, 2022, challenging the patentability of U.S. Patent No. 8,966,347 (the '347 patent) owned by Viasat, Inc. The petition specifically challenged claims 1-11 and 13-23 of the '347 patent. The challenge was based on arguments that these claims were unpatentable under 35 U.S.C. § 103 as obvious over prior art, specifically published patent applications to Diggs and Cheng.

2. Institution Decision
The Patent Trial and Appeal Board (PTAB) granted the petition and instituted review of the challenged claims.

3. Final Written Decision (2024-02-14)
The PTAB issued its Final Written Decision on February 14, 2024. In its decision, the Board found all the challenged claims (claims 1-11 and 13-23) to be unpatentable for obviousness. The Board relied on the prior art references by Diggs and Cheng in reaching its conclusion.

4. Outcome – Claims Found Unpatentable
The final outcome of the IPR at the PTAB was that all challenged claims (1-11 and 13-23) of Viasat's U.S. Patent No. 8,966,347 were found unpatentable.

5. Appeal to the Federal Circuit (Decided: 2026-01-07)
Viasat, Inc. appealed the PTAB's Final Written Decision to the United States Court of Appeals for the Federal Circuit (Case No. 2024-1483). The Federal Circuit issued its decision on January 7, 2026. The Federal Circuit reversed the PTAB's decision, finding that the Board erred in its obviousness analysis. The court concluded that while there might be overlap in the prior art circuitry performing functions of the controller and decoder of the '347 patent, nothing in the '347 patent suggested such overlap was impermissible. Consequently, the Federal Circuit reversed the finding that claims 1-11 and 13-23 were unpatentable.

6. Effect on Parallel Litigation (if any)
It is worth noting that Western Digital Technologies, Inc. and Viasat, Inc. were also involved in a patent infringement action filed in the Northern District of California (Case No. 4:22-cv-04376), filed on July 28, 2022. This district court case involved U.S. Patent Nos. 9,424,400 and 10,447,667, not the '347 patent that was the subject of this IPR. That district court case was voluntarily dismissed on April 24, 2024. While IPRs often run parallel to district court litigation and can impact them, the specific IPR (IPR2022-01171) on the '347 patent and the district court litigation on other patents appear to have proceeded independently in terms of their subject matter. The Federal Circuit's reversal of the PTAB's unpatentability finding for the '347 patent means that Viasat's patent claims remain valid, which could strengthen Viasat's position should it choose to assert the '347 patent in future litigation.

I'll research the petitioners'/plaintiffs' counsel of record in IPR2022-01171.

Let me verify the petitioner's counsel lineup and the appellate/outcome details.

Let me verify the appellate outcome and counsel profiles.

Counsel of Record for the Petitioner/Plaintiff Side (Western Digital / SanDisk)

Important framing note: In this proceeding the "plaintiff" side is the petitioner — Western Digital Technologies, Inc. (together with Western Digital Corporation and SanDisk LLC as real parties-in-interest). There is no plaintiff's complaint here; the operative appearance documents are the Petition (Paper 1), the Power of Attorney (Paper 2), Petitioner's Motion to Withdraw/Substitute Counsel (Paper 19), the Updated Power of Attorney (Paper 21), the Updated Mandatory Notices (Paper 24), and two Board orders (Papers 22 and 23). All petitioner-side counsel of record came from a single firm, Shearman & Sterling LLP (New York), which became A&O Shearman on May 1, 2024 via the Shearman/Allen & Overy combination.

Current lead counsel (from May 2023 through the Final Written Decision)

Backup / pro hac vice counsel

Superseded counsel (withdrawn May 2023)

In-house counsel

No Western Digital in-house attorney is identified as of record in the filings I reviewed — the Petition and Power of Attorney papers list only the Shearman & Sterling practitioners above. The Power of Attorney (Paper 2 / updated Paper 21) is executed on behalf of the petitioner entity rather than naming an in-house lawyer.

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Required flags — contradictions between the case metadata / prior sections and the record

The previously generated sections contain several material errors and internal contradictions that should be corrected before this is published:

1. Filing date. Metadata says the IPR was filed 2022-08-02. The PTAB docket (Patexia; Ex Parte PTAB) shows the Petition (Paper 1) was filed June 22, 2022. The 2022-08-02 date appears to be the N.D. Cal. complaint date in the separate WD v. Viasat case.
2. Institution date. One prior section says institution was 2023-02-14. The record shows institution on December 19, 2022 (Paper 13).
3. Final Written Decision date. Both prior sections say 2024-02-14. The FWD is December 13, 2023 (Paper 33), captioned "Determining All Challenged Claims Unpatentable, 35 U.S.C. § 318(a)," with oral hearing held September 27, 2023.
4. Outcome. The first "Key legal developments" block says claims 1–6 were held not unpatentable and never appealed — this is flatly wrong. The Board found all challenged claims (1–11 and 13–23) unpatentable, and the case was appealed (status: "Final Written Decision – Appealed").
5. Appeal — who appealed and the result. The second block says Western Digital appealed and the Federal Circuit reversed on 2026-01-07. In fact Viasat appealed (Fed. Cir. No. 2024-1483), and the Federal Circuit AFFIRMED the Board in a nonprecedential opinion by Judge Bryson issued January 7, 2026, holding substantial evidence supported the obviousness finding and distinguishing Becton Dickinson/Kyocera in favor of Linear Technology. Sources: CAFC opinion PDF (24-1483.OPINION.1-7-2026), IPWatchdog (Jan. 7, 2026), Bloomberg Law IP Law Daily (Jan. 8, 2026).
6. Claim scope on appeal. Viasat challenged only claim 13 (the system claims 13–23); the Board's holdings on method claims 1–11 were not appealed.
7. Related district court matter. The FWD identifies the related case as Viasat, Inc. v. Western Digital Corp., No. 6:21-cv-01230-ADA (W.D. Tex.) — not the N.D. Cal. 4:22-cv-04376 case emphasized in the prior section (that N.D. Cal. action, captioned Western Digital v. Viasat, is a separate, parallel dispute). The '347 patent's sibling, U.S. Patent 8,615,700, was challenged by Kioxia (IPR2022-01067) and by WD/Kioxia (IPR2022-01126).
8. Case caption direction. The metadata caption "Western Digital Technologies, Inc. et al. v. Viasat, Inc." is correct for the IPR (petitioner v. patent owner), but the Federal Circuit appeal is captioned in reverse: Viasat, Inc. v. Western Digital Technologies, Inc., No. 2024-1483.

Sourcing caveat: PTAB filings are not on PACER; the appearance/withdrawal facts above come from the Board's own orders (Papers 19, 21, 22, 23, 24) as mirrored on Docket Alarm/Patexia, plus the PTAB FWD (Paper 33) and firm bios. I did not locate a sealed or unavailable filing on petitioner-side counsel, but I also could not independently verify Eric Lucas's formal designation in this specific IPR, nor Kieran Kieckhefer's exact office location — both are flagged above rather than asserted.

Here is the identified counsel of record representing Viasat, Inc. in IPR2022-01171:

• Brent K. Yamashita
  • Role: Lead Counsel
  • Firm: DLA Piper, located in Silicon Valley (Palo Alto, CA).
  • Experience Note: Brent Yamashita has extensive experience as lead counsel in numerous Inter Partes Review (IPR) proceedings before the Patent Trial and Appeal Board (PTAB) and in patent litigation in federal district courts and the International Trade Commission, particularly for technology companies. His practice also includes patent prosecution in advanced technologies like flash memory.