Case: 22-1755 Document: 63 Page: 1 Filed: 09/06/2024

United States Court of Appeals for the Federal Circuit ______________________

PARKERVISION, INC., Plaintiff-Appellant

v.

QUALCOMM INCORPORATED, QUALCOMM ATHEROS, INC., Defendants-Appellees ______________________

2022-1755, 2024-2221 ______________________

Appeal from the United States District Court for the Middle District of Florida in No. 6:14-cv-00687-PGB-LHP, Judge Paul G. Byron. ______________________

Decided: September 6, 2024 ______________________

JOSHUA WRIGHT BUDWIN, McKool Smith, P.C., Austin, TX, argued for plaintiff-appellant. Also represented by MATTHEW CAMERON, JOEL LANCE THOLLANDER, RAYMOND MITCHELL VERBONCOEUR; KEVIN L. BURGESS, Marshall, TX.

EAMONN GARDNER, Cooley LLP, Denver, CO, argued for defendants-appellees. Also represented by MATTHEW J. BRIGHAM, DENA CHEN, JEFFREY S. KARR, BENJAMIN S. LIN, PRIYA B. VISWANATH, Palo Alto, CA; STEPHEN SMITH, Case: 22-1755 Document: 63 Page: 2 Filed: 09/06/2024

2 PARKERVISION, INC. v. QUALCOMM INCORPORATED

Washington, DC; MICHAEL EDWARD LOCKAMY, Bedell, Dittmar, DeVault, Pillans & Coxe, P.A., Jacksonville, FL. ______________________

Before LOURIE, MAYER, and STARK, Circuit Judges. STARK, Circuit Judge. More than nine years ago, we affirmed a judgment as a matter of law (“JMOL”) of non-infringement in a patent infringement action brought by ParkerVision, Inc. (“Par- kerVision”) against Qualcomm Inc. (“Qualcomm”) relating to wireless communications technology. ParkerVision, Inc. v. Qualcomm Inc., 621 F. App’x 1009 (Fed. Cir. 2015) (“Par- kerVision I”). ParkerVision also filed a second infringe- ment suit against Qualcomm on different but related patents. The latter case, which we will refer to as the “2014 Action,” concluded with the district court granting Qual- comm’s motion for summary judgment of non-infringement based on collateral estoppel arising from ParkerVision I. ParkerVision, Inc. v. Qualcomm Inc., 2022 WL 1230505 (M.D. Fla. Mar. 22, 2022). The district court also granted Qualcomm’s motions to exclude certain testimony Par- kerVision had proposed to present through its validity and infringement experts (“Daubert motions”). ParkerVision now appeals the disposition of the 2014 Action. We vacate the judgment of non-infringement, reverse the exclusion of testimony, and remand for further proceedings. I The litigation saga between ParkerVision and Qual- comm dates back to 2011, when ParkerVision sued Qual- comm in the United States District Court for the Middle District of Florida, alleging infringement of its patented technology relating to “down-converting” electromagnetic signals (the “2011 Action”). As we described in our Par- kerVision I decision – which ended the 2011 Action by af- firming the district court’s grant of JMOL of non- infringement – “‘[d]own-converting’ refers to converting a Case: 22-1755 Document: 63 Page: 3 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 3

modulated high-frequency electromagnetic signal into a low-frequency or ‘baseband’ signal in an electronic device such as a wireless receiver.” ParkerVision I, 621 F. App’x at 1011. ParkerVision’s down-converting system uses a technique called “energy sampling,” which “differs from the technique of ‘voltage sampling,’ which was used in conven- tional down-converting systems.” Id. As depicted in Figure 82A of one of the patents at issue in the 2011 Action, U.S. Patent No. 6,061,551 (“’551 patent”), the circuit of Par- kerVision’s down-converting system “consists of an elec- tronic switch [8206] connected on one end to an input electromagnetic signal [8204] and on the other end to a storage capacitor [8208] . . . [and] a load device [8212].” Id.

In the 2011 Action, a jury returned a verdict “rejecting Qualcomm’s invalidity claims and finding that Qualcomm directly and indirectly infringed” multiple claims across four asserted patents. Id. at 1012. Following the verdict, Qualcomm filed motions for JMOL or alternatively a new trial on infringement and invalidity issues. The district court granted Qualcomm’s motion for JMOL of non- Case: 22-1755 Document: 63 Page: 4 Filed: 09/06/2024

4 PARKERVISION, INC. v. QUALCOMM INCORPORATED

infringement but denied the motions relating to invalidity. Both ParkerVision and Qualcomm appealed. On appeal, we treated claim 23 of the ’551 patent as representative of all claims asserted in the 2011 Action. See id. (parties agreeing that differences among other as- serted claims did “not materially affect the issues on ap- peal”). Claim 23 of the ’551 patent recites: An apparatus for down-converting a carrier signal to a lower frequency signal, compris- ing: an energy transfer signal generator; a switch module controlled by said energy transfer signal generator; and a storage module coupled to said switch mod- ule; wherein said storage module receives non-neg- ligible amounts of energy transferred from a carrier signal at an aliasing rate that is sub- stantially equal to a frequency of the carrier signal plus or minus a frequency of the lower frequency signal, divided by n where n repre- sents a harmonic or sub-harmonic of the car- rier signal, wherein a lower frequency signal is generated from the transferred energy. ’551 patent at 116:24-36 (emphasis added). The last limitation of claim 23, “wherein said storage module receives non-negligible amounts of energy trans- ferred from a carrier signal . . . wherein a lower frequency signal is generated from the transferred energy,” is re- ferred to as the “generating limitation.” This “generating limitation” was the focus of the disputed issues in Par- kerVision I and is again in this latest appeal as well. Case: 22-1755 Document: 63 Page: 5 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 5

In ParkerVision I, 621 F. App’x at 1017, we affirmed the district court’s grant of JMOL of non-infringement. In doing so, we found that the generating limitation of the claims asserted in the 2011 Action required that “the ac- cused products produce a low-frequency baseband signal using energy that has been transferred . . . into a storage medium, such as a capacitor or set of capacitors.” Id. at 1013. In other words, in order to infringe representative claim 23 of the ’551 patent, the down-converting had to oc- cur at a point in the circuit located at or after the capacitor. Based primarily on the trial testimony of ParkerVision’s expert, who opined that in Qualcomm’s accused products the down-converted baseband signal “already exists before the capacitor,” we found that “Qualcomm products ob- tained the [down-converted] baseband signal from ‘some- where other than’ the energy stored in the capacitors, precluding a finding of infringement.” Id. at 1014 (empha- sis added). We subsequently denied ParkerVision’s peti- tion for rehearing. See ParkerVision, Inc. v. Qualcomm Inc., 627 F. App’x 921 (Fed. Cir. 2015). In 2014, while Qualcomm’s motions for JMOL or alter- natively a new trial were pending in the 2011 Action, Par- kerVision filed another action against Qualcomm in the Middle District of Florida (the “2014 Action”), asserting several patents that had not been at issue in the 2011 Ac- tion, including (as relevant to this appeal) U.S. Patent Nos. 7,218,907 (“’907 patent”) and 6,091,940 (“’940 patent”). The ’907 patent is in the same family as the ’551 patent and teaches technology relating to down-conversion. The ’940 patent is unrelated to the ’551 patent and describes down-conversion as well as technology relating to “up-con- verting” of electromagnetic signals. “Up-converting” refers to converting a low-frequency or baseband electromagnetic signal into a high-frequency electromagnetic signal. While down-conversion typically occurs after a wireless device re- ceives a transmitted signal, up-conversion typically occurs before a wireless device transmits signals. Case: 22-1755 Document: 63 Page: 6 Filed: 09/06/2024

6 PARKERVISION, INC. v. QUALCOMM INCORPORATED

In the 2014 Action, ParkerVision asserted certain claims primarily directed to down-conversion, referred to by the parties as “receiver claims,” and others primarily di- rected to up-conversion, referred to as the “transmitter claims.” 1 The receiver claims, according to the district court, include claims 1 and 10 of the ’907 patent and claims 24 and 331 of the ’940 patent. Illustrative of the receiver claims are claim 1 of the ’907 patent and claim 24 of the ’940 patent. Claim 1 of the ’907 patent recites: A method for down-converting an electromag- netic signal, comprising: periodically coupling an electromagnetic sig- nal that includes a carrier signal to an energy storage device and a load, wherein the peri- odic couplings occur at a rate less than twice the frequency of the carrier signal; providing, during the periodic couplings, en- ergy from the electromagnetic signal to the energy storage device, thereby changing an amount of energy stored by the energy storage device; providing, during the periodic couplings, en- ergy from the electromagnetic signal to the load; and providing, between the periodic couplings, en- ergy from the energy storage device to the load, thereby changing the amount of energy stored by the energy storage device;

1 The “transmitter claims,” according to the district court, include claims 22 and 25 of the ’940 patent and two claims of a patent that is not relevant to the issues raised in this appeal. Case: 22-1755 Document: 63 Page: 7 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 7

whereby the energy provided to the load forms a down-converted signal. ’907 patent at 130:64-131:14. Claim 24 of the ’940 patent depends from independent claim 22, which itself is a transmitter claim. Claim 22 re- cites: An apparatus for communicating comprising: (a) a transmitting subsystem comprising: (1) a switch module having a first input connected to a bias signal, a control in- put connected to a control signal, and an output generating a periodic signal, wherein said control signal is an oscil- lating signal, said control signal caus- ing said switch module to gate said bias signal, said periodic signal having an amplitude that is a function of said bias signal, and said periodic signal being a harmonically rich signal comprised of a plurality of harmonics, and (2) a filter to accept said harmonically rich signal and to output one or more desired harmonics from said plurality of harmonics; and (b) a receiving subsystem. ’940 patent at 69:33-47. Claim 24 recites: The apparatus of claim 22, wherein said re- ceiving subsystem comprises: an aliasing module, further comprising: (1) a universal frequency translation (UFT) module, said UFT module aliasing an electro- magnetic signal according to an aliasing Case: 22-1755 Document: 63 Page: 8 Filed: 09/06/2024

8 PARKERVISION, INC. v. QUALCOMM INCORPORATED

signal having an aliasing rate to down-con- vert said electromagnetic signal, and trans- ferring energy from said electromagnetic signal at said aliasing rate; (2) a signal generator generating said alias- ing signal, said aliasing signal comprising a plurality of pulses having non-negligible ap- ertures; and (3) a storage device storing energy from said UFT module. Id. at 69:54-67. Neither of the illustrative receiver claims (claim 1 of the ’907 patent and claim 24 of the ’940 patent) contains an explicit requirement that the down-converted signal be generated from energy transferred to an energy storage de- vice. That is, the receiver claims asserted in the 2014 Ac- tion do not appear, on their face, to require the “generating limitation” that turned out to be fatal to ParkerVision’s in- fringement case in the 2011 Action. During the pendency of the 2011 and 2014 Actions, Qualcomm filed several petitions for inter partes review (“IPR”) of ParkerVision’s ’940 patent. Meanwhile, Par- kerVision sued Qualcomm at the U.S. International Trade Commission (“ITC”). The parties jointly requested that the district court stay the 2014 Action pending resolution of the IPRs and the ITC proceedings, which the district court agreed to do. In one of the IPRs, Qualcomm challenged the patenta- bility of apparatus and method claims relating to up-con- version, including claim 25 of the ’940 patent. This same claim was asserted as one of the transmitter claims in the 2014 Action. The apparatus and method claims that were considered in the IPRs share certain limitations, including the requirement of generating or creating “a periodic signal having a plurality of harmonics.” Id. at 69:27-28 Case: 22-1755 Document: 63 Page: 9 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 9

(apparatus claim 21), 70:5-6 (method claim 25). We will refer to this as the “harmonically rich signal” limitation. In its final written decision, the Patent Trial and Ap- peal Board (“Board”) determined that the challenged appa- ratus claims of the ’940 patent are unpatentable as obvious because the prior art taught an apparatus that was “capa- ble of” performing functions that would satisfy the limita- tions of the apparatus claims. J.A. 38997. The Board, however, determined that Qualcomm failed to prove the challenged method claims would have been obvious, be- cause Qualcomm’s petition did not address whether a per- son of ordinary skill in the art would have been motivated to operate the prior art apparatus in a manner that would satisfy the limitations of the method claims. On appeal, we affirmed the Board’s patentability determinations. See ParkerVision, Inc. v. Qualcomm Inc., 903 F.3d 1354, 1362- 63 (Fed. Cir. 2018) (“ParkerVision II”). Thereafter, in December 2018, the district court lifted its stay in the 2014 Action and instructed the parties to “address whether any patents and claims brought in the instant litigation are affected by ParkerVision I.” J.A. 5989. Qualcomm responded with a motion for partial sum- mary judgment of non-infringement of the receiver claims of the ’907 patent, based on collateral estoppel arising from ParkerVision I (the “First Motion”). In this First Motion, Qualcomm contended that the receiver claims of the ’907 patent included “the same concept” as the “generating lim- itation” of the claims asserted in the 2011 Action, so Par- kerVision could no longer argue that Qualcomm infringed these claims. J.A. 9624. The district court denied Qualcomm’s First Motion, finding that Qualcomm failed to “show there is no material difference between the patents-at-issue in ParkerVision I and the claims now asserted by ParkerVision” in the 2014 Action. J.A. 10344. Specifically, the district court deter- mined there was expert support in the record for Case: 22-1755 Document: 63 Page: 10 Filed: 09/06/2024

10 PARKERVISION, INC. v. QUALCOMM INCORPORATED

ParkerVision’s position that, unlike the 2011 Action claims containing the generating limitation – which required en- ergy stored in the capacitors to be used to create the down- converted baseband signal – the receiver claims of the ’907 patent may only “require[] ‘a down-converted signal’ formed in a load using energy taken directly from the elec- tromagnetic signal, without charging and discharging a ca- pacitor.” J.A. 10343. Thus, in connection with the First Motion, the district court contrasted the generating limita- tion of the 2011 Action asserted claims, which required that the down-converting occur at or after the capacitor, with the receiver claims at issue in the 2014 Action, which the court recognized might lack the generating limitation and, therefore, would not exclude down-converting occur- ring before the capacitor. As trial approached in the 2014 Action, Qualcomm filed Daubert motions seeking, as relevant to this appeal, (1) ex- clusion of the testimony of ParkerVision’s validity expert, on the grounds that collateral estoppel arising from our af- firmance in ParkerVision II of the ’940 patent IPR pre- cludes ParkerVision from attempting to contradict any of the Board’s findings, and (2) exclusion of testimony from ParkerVision’s infringement experts based on its unrelia- bility, due to the experts’ failure to conduct allegedly nec- essary testing and simulations. Qualcomm also moved again for summary judgment of non-infringement (the “Second Motion”), contending, as relevant here, that (1) ParkerVision is collaterally estopped from asserting Qual- comm infringes the receiver claims of the ’907 and ’940 pa- tents, and (2) the accused products do not infringe the transmitter claims because they do not meet the “harmon- ically rich signal” limitation. The district court granted Qualcomm’s Daubert mo- tions, finding that ParkerVision II, affirming the PTAB’s invalidation of the challenged apparatus claims ’940 pa- tent, collaterally estopped ParkerVision from relitigating characteristics of the prior art reference on which Case: 22-1755 Document: 63 Page: 11 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 11

Qualcomm’s invalidity contentions rested. The district court also excluded certain infringement expert testimony, including testimony relating to infringement of the trans- mitter claims of the ’940 patent, based on its view that the experts’ opinions were unreliable. The district court then granted Qualcomm’s Second Motion. The court concluded that Qualcomm’s accused products would not infringe the receiver claims of the ’907 and ’940 patents because “there is no material dispute over whether the claims at issue here are materially similar to those in ParkerVision I,” in which we had affirmed the judgment of non-infringement. J.A. 8. With respect to the transmitter claims of the ’940 patent, the district court de- termined that because it had excluded the testimony of ParkerVision’s infringement experts, Qualcomm’s expert’s non-infringement opinion was unrebutted. Therefore, the district court granted summary judgment of non-infringe- ment of the transmitter claims as well. ParkerVision timely appealed. After briefing was com- pleted and oral argument was heard on November 6, 2023, we determined sua sponte that we lacked jurisdiction over the appeal because Qualcomm’s counterclaims for invalid- ity remained unadjudicated and, consequently, there was no final judgment. See No. 2022-1755 ECF No. 59 at 2. On July 16, 2024, we dismissed the appeal for lack of jurisdic- tion, subject to reinstatement, with the reinstated appeal to be decided by the same panel based on the briefs already filed and the oral argument heard. See id. On August 1, 2024, the district court entered a new judgment, which incorporated its prior order granting Qualcomm’s summary judgment of non-infringement and its prior judgment in favor of Qualcomm and against Par- kerVision, and also expressly dismissed without prejudice Qualcomm’s counterclaims for invalidity and any remain- ing claims and counterclaims in the case. See ParkerVi- sion, Inc. v. Qualcomm Inc., No. 6:14-cv-687-PGB-LHP, Case: 22-1755 Document: 63 Page: 12 Filed: 09/06/2024

12 PARKERVISION, INC. v. QUALCOMM INCORPORATED

ECF No. 699 (M.D. Fla. Aug. 1, 2024). On August 5, 2024, ParkerVision appealed from the August 1 final judgment. We reinstated ParkerVision’s initial appeal (No. 2022- 1755) and consolidated it with the new appeal (No. 2024- 2221). We have jurisdiction under 28 U.S.C. § 1295(a)(1). II We review the district court’s grant of summary judg- ment according to the law of the applicable regional circuit. See Lanard Toys Ltd. v. Dolgencorp LLC, 958 F.3d 1337, 1341 (Fed. Cir. 2020). The Eleventh Circuit reviews a grant of summary judgment de novo, “construing the facts and drawing all reasonable inferences in favor of the non- moving party.” Brucker v. City of Doraville, 38 F.4th 876, 881 (11th Cir. 2022) (internal quotation marks omitted). Summary judgment is appropriate when “there is no genu- ine dispute as to any material fact and the movant is enti- tled to judgment as a matter of law.” Fed. R. Civ. P. 56(a); see also Huggins v. Lueder, Larkin & Hunter, LLC, 39 F.4th 1342, 1345 (11th Cir. 2022). “A genuine dispute of material fact exists when ‘the evidence is such that a rea- sonable jury could return a verdict for the nonmoving party.’” Fernandez v. Trees, Inc., 961 F.3d 1148, 1152 (11th Cir. 2020) (quoting Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248 (1986)). We also apply regional circuit law when reviewing a district court’s evidentiary rulings. See Omega Pats., LLC v. CalAmp Corp., 13 F.4th 1361, 1368 (Fed. Cir. 2021). The Eleventh Circuit “review[s] a district court’s evidentiary rulings for abuse of discretion.” Great Lakes Ins. SE v. Wave Cruiser LLC, 36 F.4th 1346, 1353 (11th Cir. 2022). A district court abuses its discretion “where its decision rests upon a clearly erroneous finding of fact, an errant conclu- sion of law, or an improper application of law to fact.” Fur- cron v. Mail Ctrs. Plus, LLC, 843 F.3d 1295, 1304 (11th Cir. 2016) (internal quotation marks omitted). Case: 22-1755 Document: 63 Page: 13 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 13

III ParkerVision raises three issues on appeal. First, Par- kerVision contends that the district court erred in granting summary judgment of non-infringement based on the pur- ported collateral estoppel effect of ParkerVision I. Second, ParkerVision argues that the district court erred in apply- ing collateral estoppel to prevent its validity expert from offering testimony that would have been arguably incon- sistent with the Board’s findings during the IPR that re- sulted in invalidation of the apparatus claims of the ’940 patent. Finally, ParkerVision asserts that the district court abused its discretion in excluding its infringement ex- perts’ testimony as unreliable. On all three issues, we agree with ParkerVision. A We begin with the district court’s grant of Qualcomm’s Second Motion, which resulted in entry of summary judg- ment of non-infringement of the receiver claims of the ’907 and ’940 patents, based on application of collateral estoppel arising from our ParkerVision I decision. 2 Determining whether collateral estoppel, also known as issue preclusion, applies presents a procedural question we evaluate according to regional circuit law. See Soverain Software LLC v. Victoria’s Secret Direct Brand Mgmt., LLC, 778 F.3d 1311, 1314 (Fed. Cir. 2015); see also Uniloc USA, Inc. v. Motorola Mobility LLC, 52 F.4th 1340, 1346 n.3 (Fed. Cir. 2022). The Eleventh Circuit applies

2 The district court’s grant of the Second Motion also resulted in summary judgment of non-infringement of the transmitter claims of the ’940 patent. We address this as- pect of the Second Motion in connection with our ruling on the exclusion of ParkerVision’s infringement expert testi- mony. See infra Part III.C. Case: 22-1755 Document: 63 Page: 14 Filed: 09/06/2024

14 PARKERVISION, INC. v. QUALCOMM INCORPORATED

collateral estoppel where the following four elements are satisfied: (1) the issue at stake must be identical to the one involved in the prior litigation; (2) the is- sue must have been actually litigated in the prior suit; (3) the determination of the issue in the prior litigation must have been a criti- cal and necessary part of the judgment in that action; and (4) the party against whom the earlier decision is asserted must have had a full and fair opportunity to litigate the issue in the earlier proceeding. CSX Transp., Inc. v. Bhd. of Maint. of Way Emps., 327 F.3d 1309, 1317 (11th Cir. 2003). 3 We apply our own law to questions involving substantive issues of patent law, in- cluding any aspects of collateral estoppel that may have special or unique application to patent cases. See Ohio Wil- low Wood Co. v. Alps S., LLC, 735 F.3d 1333, 1342 (Fed. Cir. 2013). Thus, for instance, “the question whether a par- ticular claim in a patent case is the same as or separate from another claim has special application to patent cases, and we therefore apply our own law to that issue.” Aspex Eyewear, Inc. v. Marchon Eyewear, Inc., 672 F.3d 1335, 1341 n.1 (Fed. Cir. 2012). Whether collateral estoppel ap- plies is a question of law we review de novo. See Miccosukee

3 The outcome would be the same under Federal Cir- cuit law, which requires essentially the same four elements for collateral estoppel. See Empresa Cubana Del Tabaco v. Gen. Cigar Co., 753 F.3d 1270, 1276 (Fed. Cir. 2014) (“Issue preclusion requires four preconditions to erect a bar to re- litigation: (1) identity of the issues in a prior proceeding; (2) actual litigation of those issues; (3) necessity of the prior determination to the resulting judgment; and (4) full and fair opportunities to litigate issues for the party defending against preclusion.”). Case: 22-1755 Document: 63 Page: 15 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 15

Tribe of Indians of Fla. v. U.S. Army Corps of Eng’rs, 619 F.3d 1289, 1296 (11th Cir. 2010); see also Aspex Eyewear, Inc. v. Zenni Optical Inc., 713 F.3d 1377, 1380 (Fed. Cir. 2013). Here, the parties agree that all but the first of the four requirements for collateral estoppel are satisfied. They agree that (1) the issue of whether the accused Qualcomm products infringe the claims asserted in the 2011 Action was actually litigated, (2) the determination of that issue was a critical and necessary part of the judgment in that action, and (3) ParkerVision had a full and fair opportunity to litigate the infringement issue in that earlier proceed- ing. The sole dispute concerns whether the infringement issue in this case (the 2014 Action) is identical to the in- fringement issue litigated in the 2011 Action. The parties have stipulated that the accused products at issue here operate, in all material respects, in the same manner as the products accused of infringement in the 2011 Action. Therefore, determining whether the infringe- ment issue here is the same as the infringement issue in the 2011 Action requires only an assessment of whether the receiver claims of the ’907 and ’940 patents asserted in this case are materially the same as the claims that were the basis for the finding of non-infringement in the 2011 Action. Evaluating this issue requires a comparison of the scope of the claims at issue in the 2011 Action with the scope of the claims asserted here. See Ohio Willow, 735 F.3d at 1342 (explaining collateral estoppel applies when “the differences between the unadjudicated patent claims and adjudicated patent claims do not materially alter the question” at issue). The determination of claim scope, in turn, is “a matter of claim construction.” Ottah v. Fiat Chrysler, 884 F.3d 1135, 1139 (Fed. Cir. 2018) (internal quotation marks omitted). Consistent with this legal framework, the district court correctly identified the dispositive issue as being “whether Case: 22-1755 Document: 63 Page: 16 Filed: 09/06/2024

16 PARKERVISION, INC. v. QUALCOMM INCORPORATED

the claims [in this 2014 Action] are materially different from those in ParkerVision I.” J.A. 7 n.5. To resolve this issue, however, the district court did not undertake claim construction; nor did it analyze the claim language or con- sult any other intrinsic evidence to determine the scope of the claims asserted in this action. Instead, the district court relied on Qualcomm’s expert reports, which it found to be “unrebutted,” J.A. 8, and from this extrinsic evidence concluded that “the [r]eceiver [c]laims at issue here have the same requirements as the claims in ParkerVision I, in- cluding the ‘generating limitation.’” J.A. 7 (citing, e.g., J.A. 49082-103, 50497-500). The district court’s analysis suf- fers from several errors. First, the district court erred by failing to assess claim scope by conducting claim construction according to the process we set out in Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). Instead, as we just noted, the district court relied principally on extrinsic evidence, par- ticularly Qualcomm’s expert opinion. The proper approach to determining claim scope is to “look first to the intrinsic evidence of record, i.e., the patent itself, including the claims, the specification and, if in evidence, the prosecution history.” Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996). Extrinsic evidence, including expert and inventor testimony, dictionaries, and treatises, is “less significant than the intrinsic record in determining the legally operative meaning of claim language.” Phillips, 415 F.3d at 1317 (internal quotation marks omitted). Ad- ditionally, and importantly, “[e]xtrinsic evidence may not be used to contradict claim meaning that is unambiguous in light of the intrinsic evidence.” Profectus Tech. LLC v. Huawei Techs. Co., 823 F.3d 1375, 1380 (Fed. Cir. 2016) (internal quotation marks omitted). Hence, the district court erred by ignoring the relevant intrinsic evidence and turning directly to the extrinsic evidence in determining that the receiver claims asserted in this case have Case: 22-1755 Document: 63 Page: 17 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 17

materially the same scope as the claims that were at issue in ParkerVision I. 4 Second, the district court erred by treating Qualcomm’s expert opinion as “unrebutted,” and concluding as a conse- quence there is “no material dispute over whether the claims at issue here are materially similar to those in Par- kerVision I.” J.A. 8. While ParkerVision’s expert was not as explicit about his opinion as Qualcomm’s expert – Par- kerVision’s expert did not provide claim charts comparing the limitations of the 2011 Action claims to the 2014 Action receiver claims and did not precisely state that the gener- ating limitation is omitted from the receiver claims as- serted here – it is evident and indisputable that he repeatedly opined that there are material differences in the scope of the claims involved in the two cases that would materially alter the question of infringement. In particu- lar, ParkerVision’s expert opined that Qualcomm’s accused products infringe the asserted receiver claims of the ’907 and ’940 patents because the “down converted signal exists at the output of the mixer,” which is a point before the ca- pacitor. J.A. 40334. Because the claims in ParkerVision I, containing the generating limitation, could only be in- fringed if the down-conversion occurred at a point at or

4 We are not persuaded by Qualcomm’s suggestion that ParkerVision “invited” the district court’s error of as- sessing claim scope without conducting claim construction and largely without considering the intrinsic evidence. Ap- pellees’ Br. at 42. Qualcomm, as the party invoking collat- eral estoppel and the party moving for summary judgment, bears the burden of proving the identity of the issues liti- gated in the 2011 and 2014 Actions. See In re McWhorter, 887 F.2d 1564, 1566 (11th Cir. 1989). Thus, if any party was obligated to request claim construction, it was Qual- comm, which sought to read into the receiver claims a lim- itation that is not expressly recited in the claims. Case: 22-1755 Document: 63 Page: 18 Filed: 09/06/2024

18 PARKERVISION, INC. v. QUALCOMM INCORPORATED

after the capacitor, see ParkerVision I, 621 F. App’x at 1013-16, the expert’s infringement opinion was necessarily predicated on his understanding that the claims asserted here do not contain the generating limitation. More specif- ically, ParkerVision’s first expert, Dr. Allen, submitted a declaration (more on that below) opining that claim 1 of the ’907 patent “describes the energy that is provided to the load (during periodic couplings) from the electromagnetic signal, without passing through the energy storage device,” adding that “energy provided to the load, including the en- ergy provided directly from the electromagnetic signal, forms a down-converted signal.” J.A. 10091 (emphasis added). This opinion is plainly in conflict with the gener- ating limitation’s requirement that down-conversion occur “using energy that has been transferred . . . into a storage medium.” ParkerVision I, 621 F. App’x at 1013. The district court’s abbreviated claim scope analysis in connection with the Second Motion was inconsistent with the approach it properly took in denying Qualcomm’s First Motion. At that earlier point in the litigation, the district court found “a material issue of fact precluding summary judgment” based on the declaration filed by ParkerVision’s expert, Dr. Allen. J.A. 10344. The district court made no subsequent determination that the Allen declaration on which it had relied in denying the First Motion was no longer a part of the record when it considered the Second Motion. It appears that neither party asked the district court to strike the Allen declaration, nor to consider or ig- nore it. 5 Moreover, as we have already pointed out, the

5 After the court denied the First Motion, Dr. Allen withdrew from the case, due to health reasons, and was re- placed by Dr. Steer, who adopted Dr. Allen’s expert reports in their entirety. The record appears to contain an ambi- guity as to whether Dr. Steer also adopted the Allen Case: 22-1755 Document: 63 Page: 19 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 19

district court did not ever expressly construe the receiver claims asserted here to include the generating limitation. Therefore, the record contained the same genuine dispute of material fact that had compelled the denial of the First motion. Thus, the trial court erred by treating Qualcomm’s expert testimony as “unrebutted” and concluding there was “no material dispute over whether the claims at issue here are materially similar to those in ParkerVision I.” J.A. 8. The trial court’s error is further demonstrated by com- paring our conclusions in ParkerVision I with the question presented in the Second Motion. In ParkerVision I, 621 F. App’x at 1013, we concluded that the generating limitation in each of the claims asserted in the 2011 Action “requires that the accused products produce a low-frequency [i.e., down-converted] baseband signal using energy that has been transferred from a high-frequency carrier signal into a storage medium, such as a capacitor or set of capacitors.” This meant that the down-conversion of the signal had to occur at or after the capacitor. Our affirmance of the judg- ment of non-infringement of claim 23 of the ’551 patent was based on the undisputed fact that Qualcomm’s accused products do not practice the generating limitation, as they down-convert the baseband signal before the capacitor. See id. (ParkerVision expert testifying in 2011 Action that down-converted baseband signal in accused products “has already been created before the signal reaches the identified capacitors”) (emphasis added).

declaration – and whether doing so was necessary, as it ap- pears ParkerVision reasonably understood the collateral estoppel issue to have been conclusively resolved in its fa- vor at the time it substituted Dr. Steer for Dr. Allen. We leave it for the district court on remand to determine whether the Allen declaration is or should be part of the pertinent record (and, if requested, whether to permit ex- pansion of the record). Case: 22-1755 Document: 63 Page: 20 Filed: 09/06/2024

20 PARKERVISION, INC. v. QUALCOMM INCORPORATED

The case now before us involves the same accused prod- ucts but different claims and, potentially, a materially dif- ferent infringement question. None of the asserted receiver claims of the ’907 or ’940 patents expressly in- cludes the generating limitation or appears to otherwise in- clude a requirement that the down-converted signal be generated from the energy transferred to an energy storage device, such as a capacitor. That is, none of the asserted receiver claims in this case appears to require that the down-conversion occur at or after the capacitor; instead, the claims involved here appear to permit the down-con- version to occur before the capacitor. In fact, ParkerVi- sion’s infringement contentions allege, with expert support, that the capacitor may not even be involved in the down-conversion. 6 Absent a claim construction finding a generating limitation or similar requirement to be part of the claims, the Qualcomm accused products might infringe the receiver claims in this action even if they are found to down-convert the signal before the capacitor. Thus, we agree with ParkerVision that there is at least a dispute as to the scope of the asserted receiver claims of the ’907 and ’940 patents. Consequently, summary judgment of non-infringement based on collateral estoppel is not warranted at this stage. Instead, we vacate the grant of summary judgment and re- mand for the district court to determine the scope of the

6 Dr. Allen opined in his expert report, which was adopted by Dr. Steer, that Qualcomm’s accused products infringe the relevant limitations of, for example, claim 1 of the ’907 patent because, during periodic couplings, “a down-converted signal exists at the output of the mixer,” J.A. 40334, a point before the capacitor, meaning that the capacitor may not be involved in the down-conversion. Case: 22-1755 Document: 63 Page: 21 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 21

asserted receiver claims and further to determine whether that scope is materially different from that of the claims at issue in the 2011 Action. In defending the grant of summary judgment of collat- eral estoppel, Qualcomm relies heavily on ParkerVision’s experts in this case, who testified in deposition that the re- ceiver claims of the ’907 and ’940 patents “require that you produce a lower-frequency signal using energy that’s been transferred from a higher-frequency signal into a storage medium.” J.A. 42088. We agree that this testimony might be understood as an admission that the claims asserted in this case include a generating limitation or similar require- ment. However, this is not the sum total of opinions Par- kerVision’s experts provide; they also both opined, as already noted, that the receiver claims at issue here do not require that the down-conversion occur at or after the ca- pacitor. See, e.g., J.A. 10091, 40334. When the totality of the record evidence is taken in the light most favorable to ParkerVision, as the nonmovant, there is sufficient evi- dence from which a reasonable juror could choose to credit ParkerVision’s experts’ infringement opinions rather than view the deposition statements as admissions of non-in- fringement. See generally Insituform Techs., Inc. v. CAT Contracting, Inc., 385 F.3d 1360, 1377 (Fed. Cir. 2004) (va- cating summary judgment because totality of testimony, including “inconsistent testimony” of witness, “created a disputed issue of material fact”); see also ACLU of Fla., Inc. v. Dixie Cnty., 690 F.3d 1244, 1249 (11th Cir. 2012) (“If an affidavit differs from the statements made in a deposition, the two in conjunction may disclose an issue of credibility. Under such circumstances, a district court is not free to credit one piece of evidence and ignore the other.”) (internal citation and quotation marks omitted). Qualcomm next faults ParkerVision for asserting a po- sition that creates further factual disputes. For example, with respect to claim 1 of the ’907 patent, Qualcomm ar- gues that if a down-converted signal already exists with the Case: 22-1755 Document: 63 Page: 22 Filed: 09/06/2024

22 PARKERVISION, INC. v. QUALCOMM INCORPORATED

energy that flows directly to the load, then the energy pro- vided to the load would not “form” a down-converted signal, as required by claim 1 of the ’907 patent. See ’907 patent at 131:13-14 (“whereby the energy provided to the load forms a down-converted signal”). ParkerVision counters that the term “forms,” which it argues connotes “shapes,” has a different meaning than “generates” or “creates.” Ap- pellant’s Reply Br. at 10. With respect to claim 24 of the ’940 patent, Qualcomm contends that if the electromag- netic signal is down-converted by the UFT module (a type of switch), then other claim limitations, including “a stor- age device,” would serve no purpose. ParkerVision re- sponds that the UFT module down-converts a signal while the storage device stores energy from the UFT module. Re- gardless of the merits of the parties’ competing positions on these (and other) points, the existence of potentially mate- rial fact disputes only makes all the more clear the need for additional proceedings on remand. As a final effort to persuade us that summary judgment was appropriate, Qualcomm points to instances on which ParkerVision has relied on similarities between the re- ceiver claims at issue here and the claims adjudicated in ParkerVision I. Qualcomm shows that ParkerVision relied on the same figures to explain the receiver claims in the 2014 Action that it used to explain the claims in the 2011 Action, and also notes that ParkerVision moved to sever and stay the receiver claims in this case during the pen- dency of the appeal from the 2011 Action, based on similar- ities between the two sets of claims. These generalized acknowledgments of some overlap between the claims do not, however, constitute admissions that the patent claims themselves are materially the same in the two actions. In sum, the district court erred by concluding, without expressly assessing through the ordinary claim construc- tion process, that the scope of the claims asserted here is materially the same as the scope of those at issue in Par- kerVision I. While claim construction is ultimately a Case: 22-1755 Document: 63 Page: 23 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 23

question of law, see Teva Pharms. USA, Inc. v. Sandoz, Inc., 574 U.S 318, 320 (2015) (“The ultimate construction of the claim is a legal conclusion that the appellate court can re- view de novo.”), in this appeal we are not well-positioned to undertake claim construction in the first instance. The parties have not provided us with claim construction brief- ing. Moreover, extrinsic evidence, including the testimony of the parties’ competing experts, may need to be consid- ered. Subsidiary fact-finding in connection with claim con- struction is for the trial court to perform, subject to appellate review for clear error. See id. at 333. Thus, on remand, the district court should undertake any necessary claim construction and then determine whether the re- ceiver claims asserted in this case have the same require- ment as the generating limitation of the claims at issue in ParkerVision I. This will allow the district court to then assess whether there is a difference in claim scope that would materially alter the question of infringement of the receiver claims and, accordingly, whether summary judg- ment based on collateral estoppel is warranted. B ParkerVision next contends that the district court erred in precluding its expert from offering testimony to support the validity of the ’940 patent method claims against Qualcomm’s invalidity challenge. As we explained above, in the IPRs the Board found the ’940 patent’s appa- ratus claims invalid as obvious while at the same time re- jecting the effort to prove that patent’s method claims unpatentable. We affirmed both dispositions in ParkerVi- sion II. In ruling on Qualcomm’s Daubert motions, the dis- trict court agreed with Qualcomm that the collateral estoppel effect of having lost a substantial part of the IPRs meant ParkerVision was precluded from asking the district court (or a jury) – as part of its effort to withstand Qual- comm’s challenge to the validity of the ’940 patent’s method claims, which survived Qualcomm’s IPR – to reach differ- ent conclusions than the Board had with respect to up- Case: 22-1755 Document: 63 Page: 24 Filed: 09/06/2024

24 PARKERVISION, INC. v. QUALCOMM INCORPORATED

conversion technology and the prior art. The matter in question concerns the Board’s factual findings concerning prior art. We disagree with the trial court and, hence, re- verse the order excluding ParkerVision’s validity expert. As an initial matter, we reject Qualcomm’s contention that we lack jurisdiction and cannot consider this aspect of ParkerVision’s appeal. Qualcomm argues that the only fi- nal decision we are reviewing is the district court’s judg- ment of non-infringement. Although Qualcomm presented a defense of invalidity, the district court did not make a final determination as to validity; it only made preliminary determinations as to what evidence could be presented to the jury if the case had gone forward on the issue of valid- ity. Our jurisdiction to review district court judgments is generally limited to appeals from “a final decision of a dis- trict court.” 28 U.S.C. § 1295(a)(1); see also Halo Elecs., Inc. v. Pulse Elecs., Inc., 857 F.3d 1347, 1350 (Fed. Cir. 2017). Our decision to vacate summary judgment of non- infringement, however, means there will be further pro- ceedings on remand with respect to the asserted claims of the ’940 patent, and those proceedings are likely to include Qualcomm’s invalidity defense. If so, it is in the interest of judicial economy that we let the district court know now that it was wrong to exclude ParkerVision’s validity ex- pert’s opinion, rather than allow the district court to re- solve invalidity on an improperly truncated record, which could easily lead to yet another remand. Under such cir- cumstances, we have discretion to review an issue we be- lieve will be important on remand. See, e.g., Aspex Eyewear, 672 F.3d at 1346-47 (vacating summary judg- ment of non-infringement on res judicata grounds and re- viewing claim construction rulings in interest of judicial economy); Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, 1376 (Fed. Cir. 2014) (reviewing non-dispositive claim construction that might become important on re- mand); Advanced Software Design Corp. v. Fiserv, Inc., 641 F.3d 1368, 1378 (Fed. Cir. 2011) (same). Case: 22-1755 Document: 63 Page: 25 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 25

The application of collateral estoppel is “subject to cer- tain well-known exceptions.” B & B Hardware, Inc. v. Har- gis Indus., Inc., 575 U.S. 138, 148 (2015). One is where “the second action involves application of a different legal standard, even though the factual setting of both suits may be the same.” Id. at 154; see also Grogan v. Garner, 498 U.S. 279, 284-85 (1991) (explaining that prior judgment proven by preponderance of evidence “could not be given collateral estoppel effect” in subsequent proceeding gov- erned by clear-and-convincing standard). Although we have not previously addressed the question of whether a finding underlying an unpatentability decision in an IPR proceeding collaterally estops a patentee from making va- lidity arguments regarding separate, related claims in dis- trict court litigation, we now hold that it does not. In the IPR proceedings, Qualcomm’s burden of proof was only a preponderance of the evidence. See Google LLC v. IPA Techs. Inc., 34 F.4th 1081, 1085 (Fed. Cir. 2022) (“In an IPR, the burden of persuasion is on the petitioner to prove unpatentability by a preponderance of the evi- dence.”) (internal quotation marks omitted); see also 35 U.S.C. § 316(e). Accordingly, Qualcomm proved the capa- bilities of the prior art apparatus by a preponderance of the evidence. To prevail on its invalidity contentions in the district court, however, Qualcomm must meet a higher bur- den: clear and convincing evidence. See Microsoft Corp. v. i4i Ltd. P’ship, 564 U.S. 91, 102 (2011) (“[A] defendant rais- ing an invalidity defense bore a heavy burden of persua- sion, requiring proof of the defense by clear and convincing evidence.”) (internal quotation marks omitted). Qualcomm has not faced, let alone overcome, this burden previously. Thus, no finding of the Board (or our affirmance of the Board in ParkerVision II) estops ParkerVision from pre- senting evidence on the unresolved question of whether Qualcomm is able to prove the capabilities of the prior art apparatus (and the other components of its invalidity con- tention) by clear and convincing evidence. ParkerVision Case: 22-1755 Document: 63 Page: 26 Filed: 09/06/2024

26 PARKERVISION, INC. v. QUALCOMM INCORPORATED

should be provided an opportunity to defend the validity of its method claims, which were not shown to be unpatenta- ble in the IPR, with evidence as to what the prior art con- sidered by the Board does and does not disclose. Our decision in XY, LLC v. Trans Ova Genetics, 890 F.3d 1282 (Fed. Cir. 2018), involved a different situation. In XY, we stated that “an affirmance of an invalidity find- ing, whether from a district court or the Board, has a col- lateral estoppel effect on all pending or co-pending actions.” Id. at 1294 (emphasis added); see also Packet Intell. LLC v. NetScout Sys., Inc., 100 F.4th 1378, 1381 (Fed. Cir. 2024); Fresenius USA, Inc. v. Baxter Int’l, Inc., 721 F.3d 1330, 1344 (Fed. Cir. 2013). Once we have affirmed the invalidity of a patent claim – regardless of whether the case leading to that conclusion arose at the Board, applying a prepon- derance standard, or in the district court, applying the more stringent clear and convincing standard – the claim no longer exists and cannot be asserted as a basis for in- fringement and “the affirmance of an invalidity finding, whether from a district court or the Board, has a collateral estoppel effect on all pending or co-pending actions.” XY, 890 F.3d at 1294. Where, as here, however, we are dealing with claims that have not been found unpatentable – which is true of the asserted method claims of the ’940 patent – those claims remain presumptively valid and can only be found invalid in district court litigation by clear and con- vincing evidence. Because the district court’s application of collateral es- toppel is legal error, the district court abused its discretion in excluding the testimony of ParkerVision’s validity ex- pert. Thus, we reverse the trial court’s grant of Qual- comm’s Daubert motion. C Finally, we turn to ParkerVision’s contention that the district court erred in excluding the testimony of its in- fringement experts regarding how Qualcomm’s accused Case: 22-1755 Document: 63 Page: 27 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 27

products satisfy several disputed limitations of the ’940 transmitter claims, including “harmonically rich signal,” “gating module,” “switch module,” and “non-negligible en- ergy.” The district court granted Qualcomm’s Daubert mo- tion excluding this evidence after finding the opinions at issue are “unreliable because [they] are not supported by testing and simulation” of the accused products. J.A. 32. To be admissible, “proposed expert testimony must be supported by appropriate validation – i.e., good grounds, based on what is known.” United States v. Doak, 47 F.4th 1340, 1358 (11th Cir. 2022) (internal quotation marks omitted). Under Federal Rule of Evidence 703, an expert can have “good grounds” for his opinion even when he did not “obtain[] the basis for his opinion from personal percep- tion.” Monsanto Co. v. David, 516 F.3d 1009, 1015 (Fed. Cir. 2008). Instead, “experts can base their opinion on facts or data in the case ‘that the expert has been made aware of.’” St. Louis Condo. Ass’n, Inc. v. Rockhill Ins. Co., 5 F.4th 1235, 1245 n.8 (11th Cir. 2021) (quoting Federal Rule of Evidence 703). Moreover, “[a]s a general rule,” in the Elev- enth Circuit “questions relating to the bases and sources of an expert’s opinion affect the weight to be assigned that opinion rather than its admissibility and should be left for the jury’s consideration.” Carrizosa v. Chiquita Brands Int’l, Inc., 47 F.4th 1278, 1323 (11th Cir. 2022). Here, it is undisputed that the materials considered by ParkerVision’s experts included schematics and technical documents, which, as Qualcomm conceded, are the “type of documents . . . that experts in the field would reasonably consider in evaluating the operation of a circuit.” J.A. 61095. Relatedly, we have observed that “reliance on sci- entific test results prepared by others may constitute the type of evidence that is reasonably relied upon by experts.” Monsanto, 516 F.3d at 1015. There is, then, neither a fac- tual nor legal basis here for finding that expert testimony is unreliable unless the expert herself undertakes to test or simulate the accused products. Indeed, even Qualcomm’s Case: 22-1755 Document: 63 Page: 28 Filed: 09/06/2024

28 PARKERVISION, INC. v. QUALCOMM INCORPORATED

senior director of engineering agreed that, in this case, one could “come to an accurate understanding as to how one of the accused products works without the need to do an in- dependent simulation,” as long as one looked “solely at the simulation results that are contained in the design re- views.” J.A. 5058. ParkerVision’s experts did precisely what this Qualcomm witness testified would be sufficient. See, e.g., J.A. 51073-85. The district court’s finding that testing and simula- tions were critical for the experts’ testimony to be reliable appears to have been based on scientific literature to the effect that “‘simulation is necessary to accurately predict detailed circuit behavior.’” J.A. 35 (quoting J.A. 40107). The district court also seemed to think that ParkerVision had admitted that tests and simulations were absolutely necessary. See J.A. 34 (quoting ParkerVision’s argument that “it’s really not possible to test the actual performance of a circuit in one of these computer chips without simula- tion”). The district court committed clear error in reading the literature’s general statements, and ParkerVision’s lawyers’ arguments for discovery from Qualcomm, as es- tablishing a prerequisite for a reliable infringement opin- ion in the specific context of this case. While Qualcomm’s attacks on ParkerVision’s experts may well persuade a jury not to credit the experts’ infringement opinions, the district court should have left it to jurors to “evaluate the correct- ness of facts underlying an expert’s testimony.” i4i Ltd. P’ship v. Microsoft Corp., 598 F.3d 831, 856 (Fed. Cir. 2010); see also Liquid Dynamics Corp. v. Vaughan Co., 449 F.3d 1209, 1221 (Fed. Cir. 2006) (finding expert’s use of “in- correct data” and “wrong equations” in analysis “goes to the weight of the evidence rather than the admissibility of [the expert’s] testimony and analysis”). Thus, we conclude that the district court abused its dis- cretion by excluding the testimony of ParkerVision’s in- fringement experts. We reverse the grant of Qualcomm’s Daubert motions. We likewise vacate the district court’s Case: 22-1755 Document: 63 Page: 29 Filed: 09/06/2024

PARKERVISION, INC. v. QUALCOMM INCORPORATED 29

grant of summary judgment of non-infringement of the transmitter claims of the ’940 patent, which was based on the exclusion of ParkerVision’s infringement experts. IV We have considered the remaining arguments made by Qualcomm and find them unpersuasive. For the foregoing reasons, we vacate the district court’s entry of summary judgment of non-infringement, reverse its grant of the Daubert motions relating to ParkerVision’s validity and in- fringement experts, and remand for further proceedings consistent with this opinion. VACATED-IN-PART, REVERSED-IN-PART, AND REMANDED COSTS Costs awarded to appellant.