In March 2022, the Middle District of Florida dismissed the second of two cases filed by ParkerVision, Inc. against Qualcomm, ruling in part that certain infringement claims were barred due to collateral estoppel because the patents were too similar to others that Qualcomm was found not to infringe in a first suit. However, the Federal Circuit has now reversed and remanded this and other holdings by the lower court in a September 6 precedential decision, concluding that the district judge erred by failing to adequately compare the language of the claims at issue in the two actions. Among other issues, the appellate court also tackled a previously unresolved question over collateral estoppel based on Patent Trial and Appeal Board (PTAB) decisions where the challenged claims survived review.

Publicly traded ParkerVision began its litigation campaign back in July 2011 with the aforementioned first case against Qualcomm (3:11-cv-00719), targeting various receiver and transceiver products. In October 2013, a jury returned a $173M verdict finding that the company had infringed four patents (6,061,551; 6,266,518; 7,496,342; 6,370,371) generally related to down-converting electromagnetic signals from a higher frequency to a lower frequency, but District Judge Roy B. Dalton Jr. set aside that verdict in June 2014, granting Qualcomm’s judgment as a matter of law (JMOL) as to infringement. The Federal Circuit then upheld that decision on appeal in July 2015 (“ParkerVision I”). At issue in both that appeal and the one just decided was the “generating limitation”, which describes a portion of the claimed down-conversion system “wherein [a] storage module receives non-negligible amounts of energy transferred from a carrier signal . . . wherein a lower frequency signal is generated from the transferred energy”. In ParkerVision I, the Federal Circuit held that to infringe, “the down-converting had to occur at a point in the circuit located at or after the capacitor” (a capacitor being a possible type of “storage module”), which the court found not to be the case for the accused Qualcomm products.

Meanwhile, ParkerVision filed a second suit against Qualcomm in May 2014 (6:14-cv-00687) over a different set of patents, including a family member of the ‘551 patent (7,218,907) also related to down-conversion as well as another, unrelated patent (6,091,940) with claims related to both down-conversion and up-conversion. The parties primarily referred to the asserted claims related to down-conversion as “receiver claims” (because, per the Federal Circuit, down-conversion “typically occurs after a wireless device receives a transmitted signal”) and those related to up-conversion as the “transmitter claims” (as up-conversion “typically occurs before a wireless device transmits signals”). Notably, as would later become relevant, “the receiver claims asserted in the 2014 Action do not appear, on their face, to require the ‘generating limitation’ that turned out to be fatal to ParkerVision’s infringement case in the 2011 Action” (as later characterized by the Federal Circuit).

Additionally, during the time the 2011 and 2014 cases were pending, Qualcomm filed multiple petitions for inter partes review (IPR) of the ‘940 patent, in one of which the PTAB invalidated all of the challenged apparatus claims but none of the challenged method claims. In September 2018, the Federal Circuit affirmed this decision (“ParkerVision II”).

District Judge Paul G. Byron subsequently granted two Daubert motions from Qualcomm in the second case, one of which sought to exclude the testimony of a ParkerVision validity expert—the court holding that the Federal Circuit’s ParkerVision II decision collaterally estopped ParkerVision from relitigating its characterization of the underlying technology and prior art. In granting the other motion, the court excluded the testimony of ParkerVision’s infringement experts as unreliable due to the experts’ failure to perform independent testing and validation in support of their positions. The court then granted Qualcomm’s motion for summary judgment of noninfringement due to collateral estoppel, holding that the company did 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”, which Qualcomm was held not to infringe. As for the transmitter claims of the ‘940 patent, the court held that because it had excluded the testimony of ParkerVision’s infringement experts, the noninfringement opinion of Qualcomm’s expert was “unrebutted”—granting the motion for those claims on that basis.

ParkerVision appealed in May 2022, though the proceeding hit a late-breaking procedural speedbump: In July 2024, after briefing and oral argument had concluded, the Federal Circuit dismissed the appeal for lack of jurisdiction sua sponte (on its own initiative) for lack of jurisdiction “because Qualcomm’s counterclaims for invalidity remained unadjudicated and, consequently, there was no final judgment”. Proceedings resumed (including a newly filed appeal, consolidated with the old one) after the district court issued a revised final judgment that dismissed Qualcomm’s invalidity counterclaims without prejudice.

The Federal Circuit’s Decision on Appeal

Ruling on appeal on September 6, the Federal Circuit began with the lower court’s summary judgment of noninfringement due to collateral estoppel from ParkerVision I. Here, the appellate court noted that out of the four requirements for collateral estoppel, the parties disputed just one: whether the infringement case in the 2014 action is identical to the one litigated in the 2011 action. Given the parties’ stipulation that the accused products in the two suits operate in the same manner “in all material respects”, this question hinged only on “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”. This question must be answered by comparing the language of the claims asserted in the two cases, the Federal Circuit held.

However, the Federal Circuit ruled that Judge Byron made two key errors in his analysis. The first was that he failed to perform any claim construction in determining that the claims in suit have materially the same scope as those asserted in the first case—instead relying mainly on extrinsic evidence, including Qualcomm’s expert opinion. The second was that he should not have treated Qualcomm’s opinion as “unrebutted”, the Federal Circuit finding to the contrary that ParkerVision’s expert, despite addressing the issue in less detail than Qualcomm’s expert did, “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 particular, the Federal Circuit flagged that expert’s contention that the claims lack the generating limitation crucial to the noninfringement ruling in the first case. The court appeared to agree:

None of the asserted receiver claims of the ‘907 or ‘940 patents expressly includes the generating limitation or appears to otherwise include 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-conversion to occur before the capacitor. In fact, ParkerVision’s infringement contentions allege, with expert support, that the capacitor may not even be involved in the down-conversion. 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.

On this basis, the court held that “summary judgment of non-infringement based on collateral estoppel is not warranted at this stage” for the receiver claims, reversing and remanding for further proceedings.

Later in the opinion, the Federal Circuit also addressed the ruling that led to a judgment of noninfringement for the transmitter claims, concluding that the district court was wrong to exclude the underlying report by ParkerVision’s infringement experts due to the failure to support its conclusions based on “testing and simulation” of the products at issue. Given that ParkerVision’s experts relied upon “schematics and technical documents” that experts in the field would undisputedly have relied upon, and the Federal Circuit’s prior observation that experts may rely on test results prepared by others, the court held that there is “neither a factual nor legal basis here for finding that expert testimony is unreliable unless the expert herself undertakes to test or simulate the accused products”. Moreover, the Federal Circuit held that the “district court committed clear error” in determining that such testing and simulation was required based solely on “general statements” from general technical literature and on “ParkerVision’s lawyers’ arguments for discovery from Qualcomm”. Concluding as a result that Judge Byron abused his discretion in excluding the expert reports, the Federal Circuit overturned the order granting Qualcomm’s Daubert motions on that issue and vacated the grant of summary judgment for the transmitter claims.

The Federal Circuit additionally tackled the exclusion of ParkerVision’s expert report on validity based on collateral estoppel from the IPR decisions affirmed in ParkerVision II. The court began by declining to accept Qualcomm’s argument that it lacks jurisdiction to hear the appeal because Judge Byron “only made preliminary determinations as to what evidence could be presented to the jury if the case had gone forward on the issue of validity” and had not made a final validity determination. To the contrary, the Federal Circuit held that its decision vacating summary judgment of noninfringement means that the ensuing proceedings will likely include Qualcomm’s invalidity defense. As a result, the court determined that “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 expert’s opinion, rather than allow the district court to resolve invalidity on an improperly truncated record, which could easily lead to yet another remand”.

Turning to the merits, the Federal Circuit proceeded to rule as follows: “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 validity arguments regarding separate, related claims in district court litigation, we now hold that it does not”. The reason, per the court, stems from the different evidentiary standards that apply under the circumstances. While Qualcomm had to make the factual showing here at issue—the capabilities of a prior art apparatus—under the preponderance of the evidence standard that applies in PTAB proceedings, it had not done so under the higher clear and convincing evidence standard that applies in district court. As a result, the Federal Circuit concluded that no decision by the PTAB (nor the Federal Circuit’s affirmance in ParkerVision I) estops ParkerVision from presenting evidence on this topic—holding that it “should be provided an opportunity to defend the validity of its method claims, which were not shown to be unpatentable in the IPR, with evidence as to what the prior art considered by the Board does and does not disclose”.

The court contrasted this decision with its 2018 holding in XY v. Trans Ova Genetics. While that case established that the affirmance of invalidity decisions from district court or the PTAB means that the claim no longer exists and thus cannot have a collateral estoppel effect, the Federal Circuit reached the opposite conclusion for claims under which a patent is not invalidated: “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 convincing evidence”.

The court then reversed the grant of Qualcomm’s Daubert motion, teeing up potential further litigation on validity alongside post-remand proceedings on infringement.