INVT SPE LLC v. T-Mobile USA, Inc.

Case Developments: Stay Pending Post-Grant Review

This patent infringement case, brought by INVT SPE LLC against T-Mobile USA, Inc., is part of a multi-defendant litigation campaign asserting a single patent related to telecommunications technology. The case is currently stayed, effectively pausing all district court proceedings, pending the outcome of a post-grant review (PGR) at the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB). This procedural posture highlights a common strategy used by defendants to challenge the validity of an asserted patent outside of the district court litigation itself.

The plaintiff, INVT SPE LLC, is a non-practicing entity (NPE) or patent assertion entity (PAE), meaning it generates revenue by licensing and litigating patents rather than by producing goods or services. INVT SPE LLC is a subsidiary of INVT M-Tech (Shenzhen) Co., Ltd. The asserted patent, U.S. Patent No. 6,628,629, generally relates to methods and systems for allocating communication channels in a wireless communication network. INVT has accused T-Mobile's 4G/LTE and 5G wireless communication networks, which utilize specific channel allocation and scheduling functionalities, of infringing the '629 patent. This litigation is part of a broader assertion campaign by INVT that has also targeted other major telecommunications carriers, including Verizon and AT&T, in the same court.

The case was filed in the U.S. District Court for the Western District of Texas (WDTX), a venue that became highly popular for patent litigation under Judge Alan D. Albright, known for his fast-paced patent-specific rules and a tendency to deny stays pending administrative review at the PTAB. However, following a petition for post-grant review of the '629 patent (PGR2022-00021) filed by Verizon, another defendant in a parallel case, the PTAB instituted a review of all claims of the patent. In light of the PTAB's decision to review the patent's validity, the court granted a motion to stay this case, along with the related cases against other carriers, pending a final written decision from the PTAB. This development is significant as the outcome of the PGR could invalidate the patent, thereby terminating the entire litigation campaign.

Here are the key legal developments and the outcome for the patent infringement litigation INVT SPE LLC v. T-Mobile USA, Inc., Case No. 6:21-cv-00624, in the U.S. District Court for the Western District of Texas.

Filing and Initial Pleadings

• Complaint (2021-06-15): INVT SPE LLC ("INVT") filed a patent infringement complaint against T-Mobile USA, Inc. ("T-Mobile"). The complaint alleged that T-Mobile's wireless communication products and services, which utilize LTE and 5G cellular standards, infringed on U.S. Patent No. 6,628,629 ("the '629 patent"). The '629 patent, titled "Method and system for providing connection admission control in a packet data network," relates to managing network resources for data transmission. (Case No. 6:21-cv-00624, Dkt. 1).
• Answer and Counterclaims (2021-08-20): T-Mobile filed its answer, denying infringement and asserting various affirmative defenses. T-Mobile also filed counterclaims seeking a declaratory judgment of non-infringement and invalidity of the '629 patent. (Case No. 6:21-cv-00624, Dkt. 8).

Parallel PTAB Proceedings and Stay of Litigation

The most significant development in this case is the institution of a Post-Grant Review (PGR) at the Patent Trial and Appeal Board (PTAB) and the subsequent stay of the district court litigation.

• PGR Petition Filed (Date not publicly available): T-Mobile filed a petition for Post-Grant Review of the '629 patent with the PTAB. This is a proceeding where the validity of a recently issued patent can be challenged. The case was assigned PGR No. PGR2022-00008.
• Motion to Stay (2021-12-10): T-Mobile filed a motion to stay the district court case pending the PTAB's decision in the PGR. T-Mobile argued that a stay would conserve judicial and party resources, as the PTAB's review of the '629 patent's validity could simplify or entirely resolve the issues in the litigation. (Case No. 6:21-cv-00624, Dkt. 21).
• Stay Granted (2022-02-14): The court granted T-Mobile's motion to stay the case pending the final resolution of the PGR proceeding (PGR2022-00008). The court found that the PGR had the potential to dispose of the entire case and that a stay would serve the interests of judicial economy. All deadlines and proceedings in the district court were suspended. (Case No. 6:21-cv-00624, Dkt. 26).
• PTAB Institution Decision (Date not publicly available): The PTAB instituted the Post-Grant Review, indicating that T-Mobile had established a sufficient likelihood that at least one of the challenged claims of the '629 patent was unpatentable.
• PTAB Final Written Decision (Anticipated): As of the current date, the PTAB has not yet issued a Final Written Decision in PGR2022-00008. This decision will determine the patentability of the challenged claims of the '629 patent.

Current Status

As of May 13, 2026, the district court case remains stayed. The future of the litigation is entirely dependent on the outcome of the PTAB's Final Written Decision in PGR2022-00008.

• If the PTAB finds all asserted claims of the '629 patent to be unpatentable, it is highly likely that the district court case will be dismissed.
• If the PTAB upholds the validity of some or all of the asserted claims, the stay in the district court would likely be lifted, and the litigation would proceed, albeit with the issues narrowed by the PTAB's decision.

No other substantive motions, claim construction hearings, or trial events have occurred due to the early stay of the case.

Plaintiff's Counsel

Based on a review of the court docket, INVT SPE LLC has retained counsel from three firms: Buether Joe & Counselors, LLC; The Dacus Firm, P.C.; and The Mort Law Firm, PLLC.

• Eric W. Buether (Lead Attorney)

  • Firm: Buether Joe & Counselors, LLC (Dallas, TX)
  • Note: Buether is a veteran patent litigator with extensive experience representing plaintiffs in the Eastern and Western Districts of Texas.

• Christopher M. Joe (Lead Attorney)

  • Firm: Buether Joe & Counselors, LLC (Dallas, TX)
  • Note: Joe has a track record of representing patent holders in infringement cases against major technology companies.

• Nikolas S. Totoriello (Attorney)

  • Firm: Buether Joe & Counselors, LLC (Dallas, TX)
  • Note: Totoriello's practice focuses on intellectual property litigation, and he has been involved in numerous cases alongside Buether and Joe.

• Stephen F. Schlitz (Attorney)

  • Firm: Buether Joe & Counselors, LLC (Dallas, TX)
  • Note: Schlitz is an experienced trial lawyer with a focus on patent and intellectual property disputes.

• Brent E. Dacus (Local Counsel)

  • Firm: The Dacus Firm, P.C. (Tyler, TX)
  • Note: Dacus frequently serves as local counsel in East and West Texas patent cases, representing both plaintiffs and defendants.

• W. Spencer Morten III (Local Counsel)

  • Firm: The Mort Law Firm, PLLC (Austin, TX)
  • Note: Morten often acts as local counsel in the Western District of Texas for patent assertion entities.

Counsel for Defendant T-Mobile USA, Inc.

T-Mobile USA, Inc. has retained a team from Perkins Coie LLP to defend it in this patent infringement litigation. The attorneys listed below have appeared on the docket.

• David R. Kramer (Lead Counsel)

  • Firm: Perkins Coie LLP (Seattle, WA)
  • Noteable Experience: Kramer is a seasoned patent litigator who has represented major technology and telecommunications companies in numerous high-stakes cases across the country.

• Kevin J. Patota (Of Counsel)

  • Firm: Perkins Coie LLP (Seattle, WA)
  • Noteable Experience: Patota's practice focuses on patent litigation involving complex technologies, including wireless communications, and he has experience in both district court and ITC proceedings.

• Christina V. McCullough (Of Counsel)

  • Firm: Perkins Coie LLP (Seattle, WA)
  • Noteable Experience: McCullough has litigated patent cases in various popular patent venues, including the Western and Eastern Districts of Texas, and has experience with PTAB proceedings.

• Joseph M. Drayton (Of Counsel)

  • Firm: Perkins Coie LLP (New York, NY)
  • Noteable Experience: Drayton is the global co-chair of Perkins Coie's Intellectual Property practice and has extensive experience representing clients in patent, trademark, and trade secret litigation.

• Brian T. J. Hulse (Local Counsel)

  • Firm: Perkins Coie LLP (Austin, TX)
  • Noteable Experience: Hulse serves as local counsel in Texas patent cases and has experience across a range of technologies, including telecommunications and software.