EXHIBIT 2

Case 2:23-cv-00379-JRG-RSP Document 68-2 Filed 08/07/24 Page 1 of 4 PageID #: 1351
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

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February 1, 2024

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., Nos. 23-cv-00377 and 23-cv00379 (E.D. Tex.)

Dear Mr. Fenster:

I write on behalf of T-Mobile USA, Inc. and Sprint Corp. (collectively, “Defendants” or 

“T-Mobile”) regarding the Infringement Contentions served by Plaintiff Headwater Research 

LLC (“Headwater”) on November 20, 2023, in the above-captioned action. 

We understand that for each of U.S. Patent Nos. 8,589,541, 8,924,543, 9,198,042 and 

9,215,613 (collectively, the “Asserted Patents”), Headwater accuses “smartphones, basic 

phones, tablets, laptops, and hotspot devices sold (including those sold in bundles with data 

plans) or used by T-Mobile for use with T-Mobile’s wireless network services,” and includes 

a list of accused device models. Nov. 20, 2023 Infringement Contentions at 3–7. The items 

in these lists are identified as “comprising Apple software” or “Android software” and include 

solely end-user devices. Id. Similarly, each of the claim charts attached to Headwater’s 

infringement contentions identifies the “Accused Instrumentalities” as “smartphones, basic 

phones, tablets, laptops, and hotspot devices sold (including those sold in bundles with data 

plans) or used by T-Mobile for use with T-Mobile’s wireless network services.” Id., Exs. A–

D. 

Based on these contentions, including the lists of accused devices provided, T-Mobile 

understands that Headwater accuses solely end-user devices and functionality for each of the 

Asserted Patents. Nevertheless, Headwater’s infringement contentions also include, for each 

Asserted Patent, a vague reference to “[s]ervers, hardware, software, and services leased, 

owned, supported, and/or operated by T-Mobile comprising T-Mobile’s wireless network 

services functionality.” E.g., id. at 3. No specific servers or other network hardware or 

software are identified, nor are any network elements mentioned or depicted in the charts 

attached to Headwater’s contentions. See id., Exs. A–D. 

Headwater’s infringement contentions with respect to at least its vague references to “[s]ervers, 

hardware, software, and services” and “T-Mobile’s wireless network” are deficient in that they 

fail to comply with Local Patent Rule 3-1. P.R. 3-1 requires that the identification of accused 

instrumentalities “shall be as specific as possible,” including the “name or model number, if 

known,” of each accused instrumentality. P.R. 3-1(b). Headwater’s vague and unexplained 

references to “[s]ervers, hardware, software, and services”—terms which could apply to 

Case 2:23-cv-00379-JRG-RSP Document 68-2 Filed 08/07/24 Page 2 of 4 PageID #: 1352
Marc Fenster

Russ August & Kabat

February 1, 2024

Page 2

countless elements of “T-Mobile’s wireless network” or to the accused mobile devices—do 

not reasonably provide notice to T-Mobile as to which component(s) Headwater purports to 

accuse, let alone the “specific” allegations required by P.R. 3-1. 

Accordingly, T-Mobile understands the scope of Headwater’s infringement allegations to be 

limited to the accused end-user devices and functionality—i.e. “[p]hones, tables, wearables, 

[or] devices ... for use with T-Mobile’s wireless network services,” and will carry out its 

discovery obligations in this case consistent with that understanding.

Furthermore, T-Mobile is also unable to discern Headwater’s theories of infringement, 

undermining the notice function of the infringement contentions and substantially impairing 

T-Mobile’s ability to prepare its defenses. Pursuant to P.R. 3-1(c), Headwater’s infringement 

contentions must contain “[a] chart identifying specifically where each element of each 

asserted claim is found within each Accused Instrumentality.” P.R. 3-1(c). Headwater’s charts 

fail to do so. Although Headwater lists various end-user devices in its Infringement 

Contentions, the corresponding charts only provide screenshots for some Samsung and Apple 

products, but not every product Headwater identified, including, for example, Motorola’s moto 

g power (2022) or Google’s Pixel. This is insufficient under the Local Patent Rules. 

Furthermore, a plaintiff may only use a single chart for multiple products “if separate charts 

would be identical for each product.” UltimatePointer, LLC v. Nintendo Co., 2013 WL 

12140173, at *3 (E.D. Tex. May 28, 2013). If a plaintiff chooses to “designate and chart only 

an exemplar accused infringing product, Plaintiff must provide an explanation of the technical 

and functional identity of the products represented,” and “compare each exemplar product to 

each asserted patent on a claim by claim, element by element basis.” Id.; see also Traxcell 

Techs., LLC v. Huawei Techs. USA Inc., 2017 WL 6559256, at *5 (E.D. Tex. Dec. 21, 2017) 

(“[Plaintiff’s] contentions do not chart each accused product or otherwise identify how each 

accused product is technically or functionality equivalent to a charted product, as required by 

the rules. There is no way for the defendants to channel discovery to prepare for claim 

construction without such an indication. Identifying hundreds of products, without charting 

each product or identifying a clear link between these products is simply inadequate.”). 

Headwater’s charts do not comply with this Rule. For example, claim 1(d) of ’541 Patent 

requires the device to “determine at least an aspect of a policy based on a user input obtained 

through a user interface of the wireless end-user device or based on information from a network 

element, the policy to be applied if the service usage activity is the background activity, the 

policy at least for controlling the service usage activity.” Headwater only charts Samsung 

Galaxy devices and Apple products without alleging or showing that other accused products 

(e.g., Google, Motorola, Nokia, and Kyocera devices) or other versions of the Samsung and 

Apple products are technically and functionally identical. Additionally, Headwater’s 

Infringement Contentions for Apple’s products are not clearly stated, but instead intertwined 

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Marc Fenster

Russ August & Kabat 

February 1, 2024 

Page 3 

 

with the accusations against Samsung’s products; Headwater has not made a showing that 

these products are technically and functionally identical. 

Headwater also fails to establish an articulable theory of infringement between the asserted 

claims and the evidence concerning the accused instrumentalities. See Traxcell, 2017 WL 

6559256 at *4 (“[Plaintiff’s] infringement contentions make it impossible for a defendant to 

determine the theory of infringement with any certainty. The claims are set out, and much 

evidence concerning the accused instrumentalities is included, but no clear linkage is 

established between them.”). Headwater’s charts only include the asserted claims and excerpts 

about the accused products (e.g. screenshots of Apple phone screens, T-Mobile’s website, 

Android’s website, Microsoft’s website, etc.), but no linkage or analysis between them or 

explanation sufficient enough to provide notice of Headwater’s theory of infringement. 

* * * 

T-Mobile has already been prejudiced by Headwater’s failure to provide adequate contentions. 

The prejudice will be magnified the longer these issues go without being remedied. Please 

confirm that Headwater will promptly remedy the deficiencies contained in its Infringement 

Contentions. 

Sincerely,

/s/ Katherine Q. Dominguez

Katherine Q. Dominguez 

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