1 

THE UNITED STATES DISTRICT COURT 

FOR THE EASTERN DISTRICT OF TEXAS 

MARSHALL DIVISION

HEADWATER RESEARCH LLC, 

Plaintiff, 

 v. 

T-MOBILE USA, INC. and SPRINT CORP., 

Defendants. 

Civil Action No. 2:23-cv-00379-JRG-RSP 

(Lead Case) 

JURY TRIAL DEMANDED 

HEADWATER RESEARCH LLC, 

Plaintiff, 

 v. 

T-MOBILE USA, INC. and SPRINT CORP., 

Defendants. 

Civil Action No. 2:23-cv-00377-JRG-RSP 

(Member Case) 

JURY TRIAL DEMANDED 

DEFENDANTS’ UNOPPOSED MOTION FOR LEAVE 

TO AMEND INVALIDITY CONTENTIONS 

Defendants T-Mobile USA, Inc. and Sprint LLC (collectively, “T-Mobile” or 

“Defendants”) seek leave, per Local Patent Rule 3-6(b), to amend their Invalidity Contentions 

for good cause. Headwater Research LLC (“Plaintiff” or “Headwater”) does not oppose this 

motion. 

This is Defendants’ first request to amend their invalidity contentions. These 

amendments seek to apply in this case prior art references already disclosed to Plaintiff in related 

cases involving the same patents-at-issue1 and to provide further detail and support regarding 

1

 The patents are U.S. Patent No. 9,215,613 (“the ’613 Patent”), U.S. Patent No. 8,589,541 (“the 

’541 Patent”), U.S. Patent No. 9,198,042 (“the ’042 Patent”) and U.S. Patent No. 8,924,543 (“the 

’543 Patent”), (collectively, the “Asserted Patents”). These cases involving the Asserted Patents 

Case 2:23-cv-00379-JRG-RSP Document 52 Filed 03/04/24 Page 1 of 10 PageID #: 426
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certain of Android prior art systems already disclosed in Defendants’ Preliminary Invalidity 

Contentions (the “Android System Art”), including evidence acquired through a recent thirdparty subpoena to Google, LLC. 

Good cause exists for Defendants to amend their Invalidity Contentions because: 

Defendants were diligent in discovering the additional evidence, notifying Plaintiff, and seeking 

to amend; the Android System Art is important to Defendants’ invalidity case; and the time 

passed is minor and will not affect the case schedule or prejudice Plaintiff. E.g., Atlas Global 

Tech. LLC v. TP-Link Tech. Co., Ltd, et al., No. 21-cv-430-JRG-RSP, ECF No. 140 (E.D. Tex. 

March 8, 2023) (granting defendants’ unopposed motion for leave to amend invalidity 

contentions to add 11 claim charts from related cases); Orckit Corp. v. Cisco Sys., Inc., No. 2:22-

CV-276-JRG, ECF No. 61 (E.D. Tex. April 13, 2023) (granting defendant’s unopposed motion 

for leave to amend invalidity contentions “to include prior art documents recently received from 

third-party subpoenas”); Garrity Power Sevrs. LLC, v. Samsung Elecs. Co., No. 2:20-CV-269, 

2021 WL 4894262 at *1 (E.D. Tex. Oct. 19, 2021) (granting defendants’ motion for leave to 

amend invalidity contentions to add newly discovered evidence). 

Defendants served their Preliminary Invalidity Contentions on January 16, 2024. The 

AT&T defendants in the Related Cases served their Preliminary Invalidity Contentions on 

February 2, 2024. Defendants promptly notified Plaintiff of their intention to amend their 

Invalidity Contentions and met and conferred with Plaintiff on February 5, 2024 and again on 

February 22, 2024. Defendants continued to investigate the Android System Art and on February 

29, 2024, Defendants served a subpoena on Google requesting additional evidence in support of 

include: Headwater Research LLC v. Cellco Partnership. et al, Case No. 2:23-cv-00352-JRG-RSP 

(E.D. Tex.); Headwater Research LLC v. AT&T, Inc. et al, Case No. 2:23-cv-00397-JRG-RSP 

(E.D. Tex.); and Headwater Research LLC v. AT&T, Inc. et al, Case No. 2:23-cv-00398-JRG-RSP 

(E.D. Tex.) (collectively, the “Related Cases”).

Case 2:23-cv-00379-JRG-RSP Document 52 Filed 03/04/24 Page 2 of 10 PageID #: 427
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the Android System Art disclosed in Defendants’ Preliminary Invalidity Contentions. This 

additional evidence includes a transcript of a deposition taken of a Google witness in another 

case filed by Plaintiff asserting patents related to the Asserted Patents on January 23, 2024, 

wherein Plaintiff questioned the witness.2

The parties have met and conferred in good faith to minimize motion practice, and 

Plaintiff does not oppose this motion. Defendants therefore respectfully submit that good cause 

exists under P.R. 3-6(b) for Defendants to amend their invalidity contentions as described herein. 

I. THE PROPOSED AMENDMENTS 

U.S. Patent No. 8,589,541 

Exhibit 

No. Prior Art Reference Prior Notice to Plaintiff 

A16 Android System Art Preliminary Invalidity 

Contentions

A26 U.S. Patent No. 9,167,480 (“Erman”) Invalidity Contentions 

from AT&T case

U.S. Patent No. 8,924,543 

Exhibit 

No. Prior Art Reference Prior Notice to Plaintiff 

B9 U.S. Patent Pub. 2009/0180377 (“Sullivan”) Invalidity Contentions 

from AT&T case

B10 U.S. Patent Pub. 2008/0181208 (“Maes”) Invalidity Contentions 

from AT&T case

U.S. Patent No. 9,198,042 

Exhibit 

No. Prior Art Reference Prior Notice to Plaintiff 

C6 U.S. Patent Pub. 2008/0046965 (“Wright”) Invalidity Contentions 

from AT&T case

U.S. Patent No. 9,215,613 

Exhibit 

No. Prior Art Reference Prior Notice to Plaintiff 

D17 Android System Art Preliminary Invalidity 

Contentions

D21 U.S. Patent No. 9,167,480 (“Erman”) Invalidity Contentions 

from AT&T case

2

 The case is Headwater Research, LLC v. Samsung Electronics Co., Ltd. et al, Case No. 2:22-cv00422-JRG-RSP.

Case 2:23-cv-00379-JRG-RSP Document 52 Filed 03/04/24 Page 3 of 10 PageID #: 428
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II. ARGUMENT 

A party may amend or supplement invalidity contentions “by order of the Court, which 

shall be entered only upon a showing of good cause.” P.R. 3-6(b). “Good cause...requires a 

showing of diligence.” O2 Micro Int’l Ltd. v. Monolithic Power Sys., Inc., 467 F.3d 1355, 1366 

(Fed. Cir. 2006). Courts apply the following four-factor test to determine whether good cause has 

been shown: (1) the explanation for the failure to meet the deadline; (2) potential prejudice in 

allowing the thing that would be excluded; (3) the importance of the thing that would be excluded; 

and (4) the availability of a continuance to cure such prejudice. Here, good cause exists as all four 

factors favor granting Defendants leave for amendment. 

A. Defendants Acted Diligently and in Good Faith 

Defendants were diligent in obtaining evidence that would support the invalidity arguments 

against the Asserted Patents. First, Defendants were diligent in assessing references that became 

known through parallel litigation in Headwater’s cases against AT&T. The 281 asserted claims 

increased the time to adequately analyze these potential references. Despite the complexity, 

Defendants determined the prior art that supported the invalidity contentions within two months. 

See RJ Tech. LLC. V. Samsung Elec. Co. Ltd., No. 2:22-CV-00401-JRG-RSP, Dkt. No. 88, at *3 

(E.D. Tex. Dec. 8, 2023) (finding amending the contentions only two-months after serving the 

invalidity contentions weighs in favor of diligence); see also Optis Wireless Tech., LLC v. Huawei 

Tech. Co. LTD., No. 2:17-cv-00123-JRG-RSP, Dkt. No. 135, at *3 (E.D. Tex. Apr. 02, 2018) 

(finding it is not unreasonable for a detailed prior art search to take a few months for a case 

involving complex technology). Plaintiff has been on notice of the additional references since the 

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parties met and conferred on February 5, 2024, where Defendants communicated that they 

intended to align the invalidity contentions with those asserted in the Related Cases. 

Second, Plaintiff has been on notice of Defendants’ reliance on the Android System Art at 

least through service of Defendants’ Preliminary Invalidity Contentions on January 16, 2024. 

Defendants have continued to investigate the Android System Art, and in response to a subpoena, 

Google disclosed additional evidence to support the Android System Art through deposition 

testimony that occurred on January 23, 2024. Defendants continued to discuss the proposed 

amendment and promptly notified Plaintiff of their intent to supplement with additional evidence 

and citations in support of already-disclosed system art theories during the meet and confer on 

February 22, 2024. Ex. A (02/27/2024 Email from Zhu to Plaintiff). See Grand Overseas, Inc. v. 

CVS Pharmacy, Inc., Case No. 2:15-cv-1401-JRG, Dkt. No. 32 (E.D. Tex. Oct. 28, 2016) (granting 

motion for leave to supplement invalidity contentions to include newly discovered information 

from a third party). Therefore, Defendants have been diligent in identifying the prior art and in 

communicating it to Headwater upon its discovery. 

B. The Proposed Amendments are Important 

Defendants proposed amendments are important to Defendants’ invalidity case. 

Defendants expect to rely on the Android System Art and the additional prior art references 

disclosed in the Related Cases for their invalidity defenses. The proposed amendments help 

explain and clarify how the Android System Art (which was already disclosed in Defendants’ 

preliminary contentions) and additional prior art references (of which Plaintiff has been on notice 

in parallel cases) anticipate and/or render obvious the asserted claims of the Asserted Patents. See 

Garrity Power Sevrs. LLC., v. Samsung Elecs. Co., No. 2:20-CV-269, 2021 WL 4894262 at *2 

(E.D. Tex. Oct. 19, 2021) (finding amendments to the system art important where the defendants 

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“acknowledged the importance of the prior art by disclosing it in their initial contentions and 

expending efforts to locate” the prior art system to “supplement its contentions”); see also Atlas 

Global Technologies LLC., v. TP-Link Technologies Co., LTD., No. 2:21-cv-00430, Dkt. No. 140, 

at *1 (E.D Tex. March 08, 2023) (granting amendment of specific prior art references that were 

provided in parallel cases filed by the plaintiff). 

C. Plaintiff Will Not be Prejudiced; No Continuance is Required 

The proposed amendments will not prejudice Plaintiff, nor will they necessitate a 

continuance or any other schedule changes. As noted above, the proposed amendments provide 

further detail and support for the Android System Art that Defendants disclosed in their original 

Invalidity Contentions and add references that were disclosed to Plaintiff in the parallel Related 

Cases. See Garrity Power Sevrs., 2021 WL 4894262 at *3 (“The fact that Plaintiff would have to 

respond to invalidity theories” included in “Defendants’ timely original invalidity contentions” 

“was already baked into the situation.”); Atlas Global Tech. LLC v. TP-Link Tech. Co., Ltd, et al., 

No. 21-cv-430-JRG-RSP, ECF No. 140 (E.D. Tex. March 8, 2023); Ax Wireless, LLC v. HP, Inc., 

No. 2:22-cv-0279-JRG-RSP, Dkt. No. 99, at *4-5 (E.D. Tex. Dec. 11, 2023) (prejudice is minimal 

when amending contentions four months before the close of fact discovery); Estech Sys. IP, LLC. 

V. Mitel Networks, Inc., No. 2:21-CV-00473-JRG-RSP, Dkt. No. 368, at *5-6, (E.D. Tex. May 04, 

2013) (prejudice was mitigated where the nonmoving party had enough time to investigate the 

amended references when there was six weeks before the end of fact discovery). Plaintiff has ample 

time to examine the additional references and the already-disclosed Android System Art, given 

that there are over eight months before the Markman hearing and around ten months before the 

close of fact discovery. 

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Finally, this case is still in the early stages of fact discovery; the Markman hearing is not 

until November 19, 2024. Thus, the Court’s schedule will not need to be adjusted if leave to amend 

is granted. See Uniloc 2017 LLC v. Google LLC, No. 218-CV-00493-JRG-RSP, 2019 WL 

6465318, at *2 (E.D. Tex. Dec. 2, 2019) (finding no continuance required when neither party 

sought a continuance and the court deemed one unnecessary based on the case schedule). 

III. CONCLUSION 

For the reasons set forth herein and for any others that may appear to the Court, Defendants 

respectfully request that the Court grant their Unopposed Motion for Leave to Amend Invalidity 

Contentions. 

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Dated: March 4, 2024 Respectfully submitted, 

By: /s/ Celine J. Crowson

Celine Crowson 

HOGAN LOVELLS US LLP 

555 13th St NW, 

Washington, DC 20004 

Telephone: 202-637-5600 

celine.crowson@hoganlovells.com 

Tej Singh 

Yi Zhang 

Kyle Xu 

HOGAN LOVELLS US LLP 

4 Embarcadero Center Suite 3500 

San Francisco CA, 94111 

Telephone: 415-374-2300 

tej.singh@hoganlovells.com

yi.zhang@hoganlovells.com 

kyle.xu@hoganlovells.com

Kate Dominguez 

Charlie Sim 

GIBSON, DUNN & CRUTCHER LLP 

200 Park Avenue 

New York, NY 10166-0193 

Telephone: 212-0351-4000 

KDominguez@gibsondunn.com

CSim@gibsondunn.com

Andrew Robb 

GIBSON, DUNN & CRUTCHER LLP 

310 University Avenue 

Palo Alto, CA 94301-1744 

Telephone: 650-849-5300 

ARobb@gibsondunn.com

Melissa Richards Smith

GILLAM & SMITH LLP

303 South Washington Avenue 

Marshall, TX 75670 

903-934-8450 

Case 2:23-cv-00379-JRG-RSP Document 52 Filed 03/04/24 Page 8 of 10 PageID #: 433
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Fax: 903-934-9257 

Email: melissa@gillamsmithlaw.com

Attorneys for Defendants 

T-Mobile USA, Inc. and Sprint Corp. 

Case 2:23-cv-00379-JRG-RSP Document 52 Filed 03/04/24 Page 9 of 10 PageID #: 434
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CERTIFICATE OF SERVICE 

I hereby certify that on March 4, 2024, the foregoing was served to plaintiff’s counsel of 

record via email. 

/s/ Celine J. Crowson 

CERTIFICATE OF CONFERENCE 

I hereby certify that, on February 22, 2024, counsel for T-Mobile met and conferred with 

counsel for Plaintiff Headwater Research LLC in accordance with Local Rule CV-7(h). This 

motion is unopposed. 

/s/ Celine J. Crowson 

Celine J. Crowson 

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