EXHIBIT 6 

Case 2:23-cv-00379-JRG-RSP Document 77-1 Filed 08/29/24 Page 1 of 4 PageID #: 4824
Kate Dominguez

Direct: +1 212.351.2338

Fax: +1 212.716.0839

KDominguez@gibsondunn.com

 

Gibson, Dunn & Crutcher LLP

200 Park Avenue

New York, NY 10166-0193

Tel 212.351.4000

gibsondunn.com

Abu Dhabi  Beijing  Brussels  Century City  Dallas  Denver  Dubai  Frankfurt  Hong Kong  Houston  London  Los Angeles

Munich  New York  Orange County  Palo Alto  Paris  San Francisco  Singapore  Washington, D.C.

February 2, 2024 

VIA E-MAIL

Marc Fenster

Russ August & Kabat 

12424 Wilshire Boulevard, 12th Floor 

Los Angeles, CA 90025 

Re: Headwater Research LLC v. T-Mobile USA, Inc. et al, No. 2:23-cv-00379 and -00377 

(E.D. Tex.)

Counsel, 

We write on behalf of Defendants T-Mobile USA, Inc. and Sprint LLC (collectively, 

“T-Mobile”) regarding the excessive number of claims asserted by Plaintiff Headwater 

Research LLC (“Headwater”) in the above-captioned action. 

Headwater currently purports to assert 281 claims collectively across the four Asserted Patents. 

See Headwater’s Disclosure of Asserted Claims and Infringement Contentions at 2. A large 

majority of these claims come from a single asserted patent, U.S. Patent No. 8,589,541, where 

Headwater has asserted all of that patent’s 174 claims. 

Headwater’s contentions fail to establish an articulable theory of infringement between the 

asserted claims and the evidence concerning the accused instrumentalities. Headwater has 

made virtually no effort to explain how the disclosures it cites allegedly meet even the asserted 

independent claims. 

The inscrutability of Headwater’s contentions is only exacerbated by Headwater’s assertion of 

hundreds of dependent claims, for which Headwater provides no substantive infringement 

allegations at all in most cases. For the vast majority of the asserted dependent claims, 

Headwater’s contentions simply refer to the evidence cited for other asserted claims, without 

more. See, e.g., Ex. A to Disclosure of Asserted Claims and Infringement Contentions, cls. 

10–23, 26–76, 78–169, 171–174. For the few dependent claims where Headwater does include 

purported evidence of infringement, that evidence is still by-and-large recopied from 

Headwater’s allegations regarding the sole independent claim and the charts provide no 

additional information or explanation of how the cited disclosures meet the claim limitations. 

In either case, it is impossible for T-Mobile to discern Headwater’s infringement theory for 

virtually any of the more than 200 asserted dependent claims. 

Case 2:23-cv-00379-JRG-RSP Document 77-1 Filed 08/29/24 Page 2 of 4 PageID #: 4825
Marc Fenster

Russ August & Kabat

February 2, 2024

Page 2

Headwater’s blanket approach has prejudiced T-Mobile’s ability to investigate invalidity and 

non-infringement and imposed immense and unnecessary burden and cost in the preparation 

of T-Mobile’s defenses. Accordingly, Headwater should commit to a meaningful narrowing 

of the number of asserted claims across all Asserted Patents. Headwater’s commitment to 

claim narrowing in the near term will avoid the additional and unjustified expenses of 

unnecessarily litigating hundreds of claims through discovery. 

Accordingly, T-Mobile proposes the following schedule for narrowing of the asserted claims, 

and commensurate narrowing of T-Mobile’s prior art: 

• By February 23, 2024, Headwater shall serve a Preliminary Election of Asserted 

Claims which shall assert no more than ten claims from each patent and not more than 

a total of 32 claims.

• No later than 14 days after service of Headwater’s preliminary election, T-Mobile shall 

serve a Preliminary Election of Asserted Prior Art, which shall assert no more than 

twelve prior art references against each patent and not more than a total of 40 

references.1

 

• No later than 28 days before the service of expert reports by the party with the burden 

of proof on an issue, Headwater shall serve a Final Election of Asserted Claims which 

shall asserted no more than five asserted claims per patent from among the ten 

previously identified claims and no more than a total of 16 claims. 

• No later than the date set for the service of expert reports by the party with the burden 

of proof on an issue, T-Mobile shall serve a Final Election of Asserted Prior Art, which 

shall identify no more than six asserted prior art references per patent from among the 

twelve prior art references previously identified for that particular patent, and no more 

than 20 total references. 

This two-phase election of asserted claims and prior art references conforms to the Eastern 

District of Texas’s Model Order. T-Mobile’s proposal above modifies that Model Order to 

bring the preliminary elections earlier in time, in order to focus the issues of the case and avoid 

the additional burden of litigating Headwater’s excessive number of asserted claims. 

 1 A prior art instrumentality (such as a device or process) and associated references that 

describe that instrumentality shall count as one reference, as shall the closely related work of 

a single prior artist. 

Case 2:23-cv-00379-JRG-RSP Document 77-1 Filed 08/29/24 Page 3 of 4 PageID #: 4826
Marc Fenster

Russ August & Kabat 

February 2, 2024 

Page 3 

 

Please confirm whether Headwater is amenable to the above schedule for narrowing the issues 

in this case. T-Mobile is available to meet and confer regarding this proposal. 

Sincerely,

/s/ Katherine Q. Dominguez

Katherine Q. Dominguez 

Case 2:23-cv-00379-JRG-RSP Document 77-1 Filed 08/29/24 Page 4 of 4 PageID #: 4827