XR Communications LLC d/b/a Vivato Technologies v. AT&T Inc.
2:23-cv-00202
| E.D. Tex. | Sep 23, 2025Background
- This case involves XR Communications LLC d/b/a Vivato Technologies v. AT&T Inc. and others in the Eastern District of Texas, addressing DoE (doctrine of equivalents) and prosecution history estoppel.
- Defendants moved for partial summary judgment to preclude DoE arguments from XR’s experts Cooklev and Williams regarding the ’511, ’235, and ’369 patents.
- The court recommended GRANTING IN PART: preclude DoE for (i) the first and third elements of claim 20 of the ’511 patent, (ii) the proposition that n = 1 for claim 20 of the ’511 patent, and (iii) DoE for element 1[c] of the ’369 patent; otherwise the motion was DENIED.
- The analysis covered standard summary-judgment principles, the DoE framework, PHE (prosecution history estoppel), vitiation, and ensnarement, applied on a patent-by-patent basis.
- For the ’511 patent, the court rejected a pure waiver theory, found DoE analysis insufficient element-by-element for certain limitations, and held that PHE did not bar all DoE claims due to tangential-relationship rebuttal, but precluded the specific 1 = 1 theory for the challenged element.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| DoE preclusion for claim 20 of the ’511 patent based on element-by-element analysis | Cooklev's DoE theory applies to claim 20 despite a typographical difference. | Cooklev failed to provide element-by-element analysis for 1[a] and 1[c]; blanket DoE for claim 20 is improper. | Precluded for 1[a] and 1[c]; if 1[b] differs, precluded for 20[b] as well. |
| Whether n = 1 can be an equivalent for claim 20 of the ’511 patent | n = 1 is an alternative equivalent consistent with amendments. | Amendments narrowed the claim to require n ≥ 2; n = 1 is barred by PHE. | Precluded; n = 1 cannot be an equivalent. |
| DoE preclusion for element 1[c] of the ’369 patent based on prosecution history | DoE theory tied to non-amendment rationale and supporters; tangential relationship argument. | 1[c] narrowed during prosecution; PHE applies. | Precluded under PHE; tangential-relationship argument insufficient. |
| Application of prosecution history estoppel (PHE) and tangential relationship doctrine | Tangential Relationship Doctrine can rebut PHE for Cooklev’s theory in the ’511 patent. | PHE more broadly applies; tangential relationship must tie directly to the amendment. | PHE does not bar all DoE; but specific equivalence theories tied to amendments may be barred. |
Key Cases Cited
- Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (U.S. 2002) (prosecution history estoppel framework; foreseeability and tangential relation concepts)
- Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17 (U.S. 1997) (DoE must be applied element-by-element; function-way-result test)
- Conroy v. Reebok Int'l, Ltd., 14 F.3d 1570 (Fed. Cir. 1994) (hypothetical claim analysis for ensnarement assessment)
- Intendis GMBH v. Glenmark Pharms. Inc., USA, 822 F.3d 1355 (Fed. Cir. 2016) (hypothetical claim analysis; ensnarement framework)
- Wilson Sporting Goods Co. v. David Geoffrey & Assocs., 904 F.2d 677 (Fed. Cir. 1990) (ensnarement and DoE considerations; burden-shifting)
- Honeywell Int'l Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131 (Fed. Cir. 2004) (Tangential relationship and prosecution history principles)
- G. David Jang, M.D. v. Boston Sci. Corp., 872 F.3d 1275 (Fed. Cir. 2017) (burden on accused to present ensnarement evidence; patentee bears rebuttal burden)