Wi-Fi One, LLC v. Broadcom Corporation

United States Court of Appeals
for the Federal Circuit
______________________

WI-FI ONE, LLC,
Appellant

v.

BROADCOM CORPORATION,
Appellee

ANDREI IANCU, UNDER SECRETARY OF
COMMERCE FOR INTELLECTUAL PROPERTY
AND DIRECTOR OF THE UNITED STATES
PATENT AND TRADEMARK OFFICE,
Intervenor
______________________

2015-1944
______________________

Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2013-
00601.
______________________

Decided: April 20, 2018
______________________

DONALD PUCKETT, Nelson Bumgardner PC, Fort
Worth, TX, for appellant. Also represented by DOUGLAS
AARON CAWLEY, McKool Smith, PC, Dallas, TX; PETER J.
AYERS, Law Office of Peter J. Ayers, Austin, TX.
2 WI-FI ONE, LLC v. BROADCOM CORP.

DOMINIC E. MASSA, Wilmer Cutler Pickering Hale and
Dorr LLP, Boston, MA, for appellee. Also represented by
KEVIN GOLDMAN, KATIE SAXTON.

NATHAN K. KELLEY, Office of the Solicitor, United
States Patent and Trademark Office, Alexandria, VA, for
intervenor. Also represented by KAKOLI CAPRIHAN,
BENJAMIN T. HICKMAN, THOMAS W. KRAUSE, FRANCES
LYNCH; JOYCE R. BRANDA, MARK R. FREEMAN, MELISSA N.
PATTERSON, NICHOLAS RILEY, Appellate Staff, Civil Divi-
sion, United States Department of Justice, Washington,
DC.
______________________

Before DYK, BRYSON, and REYNA, Circuit Judges.
Opinion for the court filed by Circuit Judge BRYSON.
Dissenting opinion filed by Circuit Judge REYNA.

BRYSON, Circuit Judge.
These three consolidated cases return to the panel on
remand from the en banc court. That court reviewed, and
overturned, the panel’s decision that time-bar determina-
tions by the Patent Trial and Appeal Board (“PTAB” or
“Board”) in inter partes review proceedings are not ap-
pealable. Wi-Fi One, LLC v. Broadcom Corp., 878 F.3d
1364 (Fed. Cir. 2018) (en banc).
The three cases are related appeals from decisions of
the PTAB. In each case, the Board held various claims of
three patents owned by Wi-Fi One, LLC (“Wi-Fi”), to be
invalid for anticipation.
This panel initially wrote a precedential opinion in
appeal No. 2015-1944, and decided Appeal Nos. 2015-1945
and 2015-1946 by summary affirmance. See Wi-Fi One,
LLC v. Broadcom Corp., 837 F.3d 1329 (Fed. Cir. 2016);
Wi-Fi One, LLC v. Broadcom Corp., No. 2015-1945, 668 F.
WI-FI ONE, LLC v. BROADCOM CORP. 3

App’x 893 (Fed. Cir. 2016); Wi-Fi One, LLC v. Broadcom
Corp., No. 2015-1946, 668 F. App’x 893 (Fed. Cir. 2016).
Although the en banc court vacated the panel’s judg-
ments in all three cases, the en banc opinion addressed
only the appealability of the PTAB’s time-bar determina-
tion under 35 U.S.C. § 315(b). The court did not address
the remaining portions of the panel’s decision in Appeal
No. 2015-1944 or the aspects of the summary affirmances
in Appeal Nos. 2015-1945 and 2015-1946 that related to
the merits of Wi-Fi’s appeals.
The panel now reaffirms the portions of its three prior
decisions that were left unaffected by the en banc court’s
decision. Accordingly, in Appeal No. 2015-1944, parts III
and IV of the original panel opinion are reinstated and
are reproduced in substance as parts III and IV of this
opinion. In part II of this opinion, the panel addresses the
merits of Wi-Fi’s time-bar claim that the en banc court
held to be appealable. On that issue, we affirm the deci-
sion of the PTAB. In separate orders, we reinstate the
summary affirmances of the PTAB’s decisions in Appeal
Nos. 2015-1945 and 2015-1946. Because the time-bar
issue raised in those cases is identical to the time-bar
issue raised in Appeal No. 2015-1944, we affirm the
PTAB’s decision as to the time-bar issue in those cases as
well.
I
A
The patent at issue in this case, U.S. Patent No.
6,772,215 (“the ’215 patent”), is directed to a method for
improving the efficiency by which messages are sent from
a receiver to a sender in a telecommunications system to
advise the sender that errors have occurred in a particu-
lar message.
In the technology described in the patent, data is
transmitted in discrete packets known as Protocol Data
4 WI-FI ONE, LLC v. BROADCOM CORP.

Units (“PDUs”). The useful data or “payload” in those
packets is carried in what are called user data PDUs (“D-
PDUs”). Each D-PDU contains a sequence number that
uniquely identifies that packet. The sequence number
allows the receiving computer to determine when it either
has received packets out of order or has failed to receive
particular packets at all, so that the receiver can correctly
combine the packets in the proper order or direct the
sender to retransmit particular packets as necessary.
The receiver uses a different type of packet, a status
PDU (“S-PDU”), to notify the sender of the D-PDUs it
failed to receive. The ’215 patent is concerned with organ-
izing the information contained in S-PDUs efficiently so
as to minimize the size of the S-PDUs, thus conserving
bandwidth.
The patent discloses a number of methods for encod-
ing the sequence numbers of missing packets in S-PDUs.
Some of those methods use lists that indicate which
packets are missing by displaying the ranges of the se-
quence numbers of the missing packets. Other methods
are based on bitmaps that use binary numbers to report
on the status of a fixed number of packets relative to a
starting point.
Depending on how many packets fail to be properly
delivered and the particular sequence numbers of the
errant packets, different methods can be more or less
efficient for encoding particular numbers and ranges of
errors. In order to leverage the benefits of the different
encoding methods, the patent discloses an S-PDU that
can combine multiple message types in an arbitrary
order, with “no rule on the number of messages or the
type of message that can be included in the S-PDU.” ’215
patent, col. 7, ll. 55-57. Using that technology, S-PDUs
can be constructed with a combination of the encoding
types best suited for the particular errors being encoded,
WI-FI ONE, LLC v. BROADCOM CORP. 5

so that the S-PDU can be more compact than an S-PDU
that uses a single encoding type.
B
In 2010, Wi-Fi’s predecessors, Ericsson, Inc., and Te-
lefonaktiebolaget LM Ericsson (collectively, “Ericsson”)
filed a patent infringement action against D-Link Sys-
tems, Inc., and several other defendants in the United
States District Court for the Eastern District of Texas.
Ericsson alleged infringement of the ’215 patent and eight
other patents. Following a jury trial, that case resulted in
a judgment of infringement as to the ’215 patent and two
other patents, U.S. Patent Nos. 6,424,625 (“the ’625
patent”) and 6,566,568 (“the ’568 patent”). See generally
Ericsson, Inc. v. D-Link Sys., Inc., 773 F.3d 1201 (Fed.
Cir. 2014). 1
In 2013, shortly after judgment was entered in the
district court action, Broadcom petitioned for inter partes
review of the ’215 patent, the ’625 patent, and the ’568
patent. Broadcom was the manufacturer of two chips that
formed the basis for some of the infringement allegations
in the district court case, but Broadcom was not a defend-
ant in that litigation. The inter partes review proceeding
at issue in this case (PTAB No. IPR2013-00601) concerned
the ’215 patent. The ’568 patent was at issue in PTAB
No. IPR2013-00602, which is the subject of Appeal No.
2015-1945 in this court, and the ’625 patent was at issue
in PTAB No. IPR2013-00636, which is the subject of
Appeal No. 2015-1946 in this court.

1 During the proceedings before the PTAB, Ericsson
assigned its interest in the ’215 patent to Wi-Fi. For
simplicity, Wi-Fi will be referred to as the patent owner
throughout this opinion.
6 WI-FI ONE, LLC v. BROADCOM CORP.

At the outset of the PTAB proceedings, Wi-Fi sought
to bar Broadcom from obtaining inter partes review of the
’215 patent. Wi-Fi contended that some or all of the
defendants in the D-Link case were in privity with Broad-
com or were real parties in interest in the inter partes
review proceeding brought by Broadcom. Because the D-
Link defendants would be time-barred from seeking inter
partes review under 35 U.S.C. § 315(b), Wi-Fi argued that
Broadcom’s petition should be time-barred as well. The
Board rejected that argument, holding that the evidence
did not show either that Broadcom was in privity with
any of the D-Link defendants or that any D-Link defend-
ant was a real party in interest in the inter partes review
proceeding.
The Board then instituted inter partes review of the
’215 patent, finding that there was a reasonable likelihood
that the challenged claims were anticipated by U.S.
Patent No. 6,581,176 to Seo. The Board declined to
institute review based on another reference that the
Board considered redundant in light of Seo.
Seo teaches improvements to what are known as neg-
ative acknowledgement (“NAK”) frames. NAK frames are
sent by the receiving unit to inform the transmitting unit
that frames sent by the transmitting unit were misdeliv-
ered. The Seo method uses a single packet to provide
information about multiple misdelivered frames, so that
“only one NAK control frame for all missed user data
frames is transmitted to a transmitting station to require
a retransmission of the missed user data when a timer for
an NAK is actually expired.” Seo, col. 5, ll. 32-35.
Seo describes the structure of the disclosed NAK
frames. The frames include a field called “NAK_TYPE”
that indicates how the NAK frame represents missing
frames. If the NAK_TYPE is set to “00,” then the missing
frames are encoded as a list, and the frame requests
retransmission of all user data frames between the first
WI-FI ONE, LLC v. BROADCOM CORP. 7

missing frame and the last, represented by the “FIRST”
and “LAST” values. If the NAK_TYPE is set to “01,” then
the NAK frame transmits information about the missing
transmitted frames using a bitmap. In that case, the
NAK frame contains the field “NAK_MAP_SEQ” to identi-
fy the starting point of the bitmap and the field
“NAK_MAP” to transmit the bitmap.
Before the Board, Wi-Fi argued that the NAK_TYPE
field disclosed in Seo is not a “type identifier field” and
that Seo therefore does not satisfy the type identifier field
limitation of the ’215 patent. Wi-Fi further argued that,
even if Seo discloses that feature, the NAK_TYPE field is
not found within a “message field,” as required by the
claims at issue. The Board rejected those arguments,
found that Seo disclosed all the limitations of the chal-
lenged claims of the ’215 patent, and therefore held those
claims to be unpatentable. The Board also rejected
Wi-Fi’s argument that claim 15 of the ’215 patent re-
quired some sort of “length field,” which Seo did not
disclose. Finally, the Board held that Wi-Fi had not
shown that Broadcom was in privity with the D-Link
defendants, and therefore Broadcom was not barred from
filing a petition for inter partes review.
II
On appeal, Wi-Fi reprises the argument that Broad-
com’s petition for inter partes review is time-barred. Wi-
Fi points out that the D-Link defendants would have been
barred from seeking inter partes review of any of the
claims at issue in the district court litigation because they
did not petition for inter partes review within one year of
the date on which they were served with the complaint in
the district court action. See 35 U.S.C. § 315(b). Under
that statute, Wi-Fi argues that Broadcom’s petition for
inter partes review should have been dismissed because
one or more of the D-Link defendants was in privity with
8 WI-FI ONE, LLC v. BROADCOM CORP.

Broadcom or was a real party in interest in the inter
partes review proceeding.
Section 315(b) provides, in pertinent part: “An inter
partes review may not be instituted if the petition re-
questing the proceeding is filed more than 1 year after the
date on which the petitioner, real party in interest, or
privy of the petitioner is served with a complaint alleging
infringement of the patent.” The use of the familiar
common law terms “privy” and “real party in interest”
indicate that Congress intended to adopt common law
principles to govern the scope of the section 315(b) one-
year bar. See Beck v. Prupis, 529 U.S. 494, 500-01 (2000)
(“[W]hen Congress uses language with a settled meaning
at common law, Congress ‘presumably knows and adopts
the cluster of ideas that were attached to each borrowed
word in the body of learning from which it was taken
. . . .” (quoting Morrissette v. United States, 342 U.S. 246,
263 (1952))); see also 154 Cong. Rec. S9987 (daily ed. Sept.
27, 2008) (statement of Sen. Kyl) (“The concept of privity,
of course, is borrowed from the common law of judg-
ments.”).
To determine whether a petitioner is in privity with a
time-barred district court litigant, the Board conducts a
“flexible” analysis that “seeks to determine whether the
relationship between the purported ‘privy’ and the rele-
vant other party is sufficiently close such that both should
be bound by the trial outcome and related estoppels.”
Patent and Trademark Office (“PTO”), Office Patent Trial
Practice Guide, 77 Fed. Reg. 48,756, 48,759 (Aug. 14,
2012); see also id. (“Privity is essentially a shorthand
statement that collateral estoppel is to be applied in a
given case . . . .” (quoting 154 Cong. Rec. S9987 (daily ed.
Sept. 27, 2008) (statement of Sen. Kyl))). To decide
whether a party other than the petitioner is the real party
in interest, the Board seeks to determine whether some
party other than the petitioner is the “party or parties at
whose behest the petition has been filed.” Id. at 48,759.
WI-FI ONE, LLC v. BROADCOM CORP. 9

“[A] party that funds and directs and controls an IPR or
[post-grant review] proceeding constitutes a ‘real party-in-
interest,’ even if that party is not a ‘privy’ of the petition-
er.” Id. at 48,760.
The interpretation of the concepts of privity and real
party in interest set forth in the PTO’s Office Trial Prac-
tice Guide and applied by the Board is consistent with
general legal principles. See Taylor v. Sturgell, 553 U.S.
880, 893-95 & n.8 (2008) (Privity is “a way to express the
conclusion that nonparty preclusion is appropriate on any
ground”; “a nonparty is bound by a judgment if she ‘as-
sume[d] control’ over the litigation in which that judg-
ment was rendered.”); see also 18A Charles Alan Wright,
Arthur R. Miller & Edward H. Cooper, Federal Practice
and Procedure § 4451, at 356 (3d ed. 2017) (“[I]t should be
enough that the nonparty has the actual measure of
control or opportunity to control that might reasonably be
expected between two formal coparties.”). 2
A
On the merits of the section 315(b) issue, Wi-Fi first
argues that the Board applied the wrong legal standard
when it determined that no district court defendant was
either a privy of Broadcom or a real party in interest in
the inter partes review proceeding. Specifically, Wi-Fi
argues that the Board improperly required Wi-Fi to
satisfy “a hard and absolute requirement that Broadcom
must have had the right to control the District Court
Litigation in order to find that a District Court Defendant
was a real party in interest or privy,” and that the Board

2 Wi-Fi has not taken issue with the analysis of the
requirements to establish privity or real party in interest
status under section 315(b) as set forth in the PTO’s
Office Trial Practice Guide.
10 WI-FI ONE, LLC v. BROADCOM CORP.

“made it abundantly clear that it viewed the District
Court Defendants’ right to control this IPR to be of no
importance whatsoever.” Under the Board’s legal test,
according to Wi-Fi, “it is irrelevant if a District Court
Defendant has an absolute right to control Broadcom’s
conduct of the IPR (and even if it has been exercising
actual control all along, such that Broadcom is a mere
shill).”
Wi-Fi mischaracterizes the Board’s decisions regard-
ing section 315(b). Contrary to Wi-Fi’s contention, the
Board recognized that there are a number of circumstanc-
es in which privity might be found, including when the
nonparty controlled the district court litigation. The
Board’s decision to focus on that ground was in response
to the specific arguments that Wi-Fi raised on the privity
issue.
In its motion for additional discovery, Wi-Fi began by
noting that the Supreme Court in Taylor set forth six
factors to consider in determining whether a nonparty to
an action is bound by the judgment in the action. Wi-Fi
argued that this case was governed by the factors provid-
ing for nonparty preclusion based on a pre-existing “sub-
stantive legal relationship” with a party to the action and
the opportunity to control the litigation. In particular,
Wi-Fi argued that the evidence would show that, by
virtue of its indemnity relationship with at least two of
the D-Link defendants, Broadcom “had the opportunity to
control and maintains a substantive legal relationship
with the D-Link Defendants sufficient to bind Broadcom
to the District Court’s judgment.”
In its decision on Wi-Fi’s motion, the Board first ob-
served that privity depends on “whether the relationship
between a party and its alleged privy is ‘sufficiently close
such that both should be bound by the trial outcome and
related estoppels.’” The Board further noted that
“[d]epending on the circumstances, a number of factors
WI-FI ONE, LLC v. BROADCOM CORP. 11

may be relevant to the analysis, including whether the
non-party ‘exercised or could have exercised control over a
party’s participation in a proceeding,’ and whether the
non-party is responsible for funding and directing the
proceeding.”
Turning to Wi-Fi’s argument, the Board stated that
“[w]hen a patent holder sues a dealer, seller, or distribut-
er of an accused product, as is the case at hand, indemnity
payments and minor participation in a trial are not
sufficient to establish privity between the non-party
manufacturer of the accused device and the defendant
parties.” The Board added that the fact that Broadcom
filed an amicus curiae brief in the appeal from the district
court judgment “shows interest in the outcome,” but “does
not bind Broadcom to the trial below outcome or show
that Broadcom exercised control over that outcome.” Nor
did Broadcom’s litigation activity in another forum or its
filing a petition for inter partes review “show control of
the Texas Litigation or otherwise show that Broadcom
would be bound by that outcome.”
In its request for rehearing of the Board’s discovery
order, Wi-Fi argued that it was error for the Board to
require a showing that Broadcom controlled the Texas
litigation; according to Wi-Fi, a “community of interest”
was sufficient to establish privity. Responding to that
argument, the Board noted that the PTO’s Office Patent
Trial Practice Guide “emphasizes control, which implies
that control is an important factor to establish privity.”
Finally, in its request for rehearing of the Board’s Fi-
nal Written Decision, Wi-Fi again argued that the Board
had erred in “applying a legal standard imposing an
inflexible standard requiring that Petitioner must have
exercised control over the District Court Defendants in
the District Court Litigation.” In addition, Wi-Fi argued
that the Board had neglected to address the “real-party-
in-interest” issue. Wi-Fi contended that under the
12 WI-FI ONE, LLC v. BROADCOM CORP.

Board’s standard, Broadcom’s petition would not be
barred “even if there were irrefutable evidence that the
District Court Defendants had expressly hired Broadcom
to file this IPR petition, and that the District Court De-
fendants were paying for and controlling every aspect of
Broadcom’s IPR activity.”
In its decision on Wi-Fi’s request for rehearing, the
Board explained that it had previously focused primarily
on Broadcom’s “exercise of control, or opportunity to
exercise control over the prior District Court lawsuit”
because that was the focus of Wi-Fi’s argument. The
Board went on to say that its earlier decisions “did not
characterize the legal standard, for all cases, as being
limited strictly to a petitioner’s control, or opportunity to
control, a non-party in previous litigation.” The Board
explained that, in its previous decisions in the case, it had
addressed Wi-Fi’s theory “that the indemnity agreements
imply that the District Court Defendants are real parties
in interest in these inter partes reviews.”
The Board thus made clear that it understood that
privity and real-party-in-interest status could be estab-
lished not only by Broadcom’s exercise of control over the
district court proceedings, but also by the D-Link defend-
ants’ exercise of control over the inter partes review
proceeding. In sum, a review of the Board’s decisions in
this case, in the context of the arguments Wi-Fi made at
each stage, show that the Board did not apply a legally
erroneous standard in deciding the “real party in interest,
or privy” issue. 3

3 The dissent faults the Board for not discussing all
of the Taylor factors bearing on a finding of privity. But
the Board properly focused on the factors that Wi-Fi
raised in its argument. While it recognized that a variety
WI-FI ONE, LLC v. BROADCOM CORP. 13

B
Wi-Fi next contends that the Board improperly denied
its requests for discovery of evidence such as the indemni-
ty agreements between Broadcom and two of the D-Link
defendants. That evidence, according to Wi-Fi, would
have established that Broadcom and those defendants
were in privity or that those defendants were real parties
in interest in the IPR proceeding.
Discovery in inter partes review proceedings is more
limited than in proceedings before district courts or even
other proceedings before the PTO. By statute, the Direc-
tor of the PTO is authorized to prescribe regulations
“setting forth standards and procedures for discovery of
relevant evidence, including that such discovery shall be
limited to—(A) the deposition of witnesses submitting
affidavits or declarations; and (B) what is otherwise
necessary in the interest of justice.” 35 U.S.C. § 316(a)(5).
The legislative history of the America Invents Act con-
firms that “[g]iven the time deadlines imposed on these
proceedings,” it was intended that the PTO would “be
conservative in its grants of discovery.” 154 Cong. Rec.
S9988-89 (daily ed. Sept. 27, 2008) (remarks of Sen. Kyl).
By regulation, the Board has provided for limited
mandatory discovery, as well as a category called “addi-
tional discovery.” 37 C.F.R. § 42.51. The discovery sought
by Wi-Fi did not qualify as mandatory discovery and
therefore was allowable, if at all, only as “additional
discovery.” The Board’s rules provide that a party seek-
ing additional discovery “must show that such additional
discovery is in the interests of justice.” Id. § 42.51(b)(2)(i).
That standard is more restrictive than the “good cause”

of factors can contribute to a finding of privity, it limited
its discussion to the arguments made by Wi-Fi.
14 WI-FI ONE, LLC v. BROADCOM CORP.

standard that applies in post-grant review and covered
business method proceedings. Office Patent Trial Practice
Guide, 77 Fed. Reg. at 48,761. Additional discovery, the
Board has ruled, should be confined to “particular limited
situations, such as minor discovery that PTO finds to be
routinely useful, or to discovery that is justified by the
special circumstances of the case.” Apple Inc. v. Achates
Reference Publ’g Inc., No. IPR2013-00080, 2013 WL
6514049, at *2 (PTAB Apr. 3, 2013) (quoting 154 Cong.
Rec. S9988-89 (daily ed. Sept. 27, 2008) (remarks of Sen.
Kyl)).
After Broadcom petitioned for inter partes review, Wi-
Fi moved for additional discovery under 37 C.F.R.
§ 42.51(b). In its motion, Wi-Fi argued that the evidence
would show that “Broadcom is in privity with at least one
D-Link Defendant.” Wi-Fi cited evidence that at least two
of the defendants had indemnity agreements with Broad-
com, that Broadcom had communicated with some of the
D-Link defendants during that litigation, and that, more
generally, “Broadcom has been working behind the scenes
to help defeat Ericsson’s infringement claims against its
customers.” That level of coordination, Wi-Fi contended,
“raises serious questions about whether Broadcom is in
privity with the defendants and is likewise time barred
from filing these petitions by § 315(b).”
Wi-Fi requested a variety of documents, including any
indemnity agreements, joint defense agreements, or other
agreements relating to cooperation between Broadcom
and any of the D-Link defendants. Wi-Fi also sought any
correspondence between Broadcom and any of the D-Link
defendants relating to (1) the filing of Broadcom’s peti-
tions for inter partes review; (2) possible intervention by
Broadcom in the D-Link litigation; (3) claim construction
or interpretation of any of the patents at issue in that
litigation; and (4) the validity or invalidity of any of the
patents at issue in that litigation.
WI-FI ONE, LLC v. BROADCOM CORP. 15

Under the Board’s procedures, the burden is on the
party seeking discovery to show that the requested dis-
covery would be likely to produce favorable evidence. 37
C.F.R. § 42.51(b)(2) (“The moving party must show that
such additional discovery is in the interests of justice.”);
Apple Inc., 2013 WL 6514049, at *2; Garmin Int’l, Inc. v.
Cuozzo Speed Techs. LLC, No. IPR2012-00001, 2013 WL
11311697, at *3 (PTAB Mar. 5, 2013) (“[T]he requester of
information should already be in possession of a threshold
amount of evidence or reasoning tending to show beyond
speculation that something useful will be uncovered.
‘Useful’ in that context does not mean merely ‘relevant’
and/or ‘admissible.’ In [context], ‘useful’ means favorable
in substantive value to a contention of the party moving
for discovery.”).
The Board decided that Wi-Fi had not met that
standard, and therefore denied discovery. The Board’s
administration of its rules for trial proceedings is re-
viewed for an abuse of discretion. Ultratec, Inc. v. Cap-
tionCall, LLC, 872 F.3d 1267, 1272 (Fed. Cir. 2017);
Redline Detection, LLC v. Star Envirotech, Inc., 811 F.3d
435, 442 (Fed. Cir. 2015).
On appeal, Wi-Fi points to the evidence it presented
regarding the relationship between Broadcom and the D-
Link defendants, which included communications with
one of the D-Link defendants regarding the district court
litigation, an amicus brief filed by Broadcom in the appeal
of that case, and Broadcom’s use of the report of one of the
plaintiff’s experts from the district court litigation. In Wi-
Fi’s view, that evidence indicates that Broadcom and the
D-Link defendants were “closely coordinating their oppo-
sition to the ’215 patent,” which should have been suffi-
cient for the Board to order disclosure of the indemnity
agreements and other requested discovery.
The Board began its analysis of the discovery issue by
asking whether there existed more than a “mere possibil-
16 WI-FI ONE, LLC v. BROADCOM CORP.

ity” or “mere allegation that something useful [to the
proceeding] will be found.” It then engaged in a detailed
analysis of the issue of privity as applied in the context of
section 315(b), from which it concluded that “[t]o show
privity requires a showing that Broadcom would be bound
to the outcome of the Texas Litigation,” and that “[t]o be
bound, in normal situations, Broadcom must have had
control over the Texas Litigation.” Under that standard,
the Board concluded that “[p]aying for trial expenses
pursuant to indemnity normally does not establish privity
or control,” and that Wi-Fi’s “evidence and arguments fail
to show that the sought-after discovery would have more
than a mere possibility of producing useful privity infor-
mation.”
As noted, that legal standard is consistent with gen-
eral legal principles, as explained in the PTO’s Office
Patent Trial Practice Guide, 77 Fed. Reg. at 48759-60.
Given that the Board explored the discovery issue in
detail and applied the proper legal test for finding privity
or real party in interest status under section 315(b), we
decline to hold that the Board abused its discretion when
it concluded that additional discovery was not warranted
in this case.
C
Finally, Wi-Fi argues that the Board failed to provide
an adequate explanation for its ruling on the section
315(b) issue and that its decision on that issue was not
supported by substantial evidence. We disagree with both
propositions.
In its Final Written Decision, the Board ruled that
Wi-Fi had not shown that Broadcom was in privity with
the D-Link defendants or that any of the D-Link defend-
ants was a real party in interest in the inter partes review
proceeding. In so ruling, the Board explained that Wi-Fi’s
arguments were no different from the arguments Wi-Fi
had made in its motion for additional discovery several
WI-FI ONE, LLC v. BROADCOM CORP. 17

months earlier, and that “[t]he argument and evidence
are unpersuasive for [the] same reasons explained in our
Decision on Patent Owner’s Motion for Additional Discov-
ery (Paper 23), which we adopt and incorporate by refer-
ence.” As described above, that earlier decision dealt at
length with the section 315(b) issue, as did the Board’s
decision in response to Wi-Fi’s request for reconsideration
of that order. In its subsequent decision in response to
Wi-Fi’s request for rehearing of the Final Written Deci-
sion, the Board further addressed the section 315(b) issue,
again writing on that issue at some length. In light of its
multiple and detailed discussions of the section 315(b)
issue, the Board cannot fairly be accused of not providing
an adequate explanation for its decision on that question.
We further hold that the Board’s decision was sup-
ported by substantial evidence. There was essentially no
evidence before the Board that any of the D-Link defend-
ants was a real party in interest in the inter partes review
proceeding. While Wi-Fi has speculated that Broadcom
may have been serving the interests of the D-Link de-
fendants when it sought inter partes review, Broadcom
clearly has an interest of its own in challenging the ’215
patent, based on its manufacture of the assertedly infring-
ing chips. Other than Wi-Fi’s conjecture, there is no
evidentiary support for Wi-Fi’s theory that Broadcom was
acting at the behest or on behalf of the D-Link defend-
ants.
On the issue of privity, the Board reasonably conclud-
ed that the evidence failed to show that Broadcom had
sufficient control over the district court litigation to
justify treating Broadcom as a virtual party to that pro-
ceeding. In applying the privity requirement of section
315(b), the Board has stated that the inquiry typically
requires proof that the party in question had sufficient
control over the prior proceeding that it could be bound by
the results of that proceeding. See Aruze Gaming Macau,
Ltd. v. MGT Gaming, Inc., No. IPR2014-01288, 2015 WL
18 WI-FI ONE, LLC v. BROADCOM CORP.

780607, at *4-8 (PTAB Feb. 20, 2015) (discussing the six
Taylor factors and emphasizing the “flexible and equita-
ble considerations” involved); BAE Sys. Info. & Elec. Sys.
Integration, Inc. v. Cheetah Omni, LLC, No. IPR2013-
00175, 2013 WL 5653116, at *2 (PTAB July 23, 2013)
(holding that parties are not privies based only on a
customer-seller relationship); Apple Inc., 2013 WL
6514049, at *2-4 (holding that an indemnification provi-
sion is not indicative of privity or real-party-in-interest
status).
There was no such showing of control in this case.
Wi-Fi’s evidence showed that Broadcom’s interests as to
the issue of infringement were generally aligned with
those of its customers, and that Broadcom had indemnity
agreements with at least two of the D-Link defendants.
But the evidence did not show that Broadcom had the
right to control that litigation or otherwise participated in
that litigation to the extent that it should be bound by the
results. Nor did any evidence suggest that the D-Link
defendants were the real parties in interest in Broadcom’s
inter partes review petition. 4 Section 315(b) thus does not
bar Broadcom from petitioning for inter partes review of
the ’215 patent. Based on the full record before the
Board, we conclude that substantial evidence supports the
Board’s decision on the “real party in interest, or privy”
issue.

4 Before the Board, Broadcom introduced evidence
that it did not control the district court litigation or
decisions made in that litigation. Although the document
presenting that evidence was designated as confidential,
the evidence was properly before the Board for its consid-
eration and is available to us on appeal.
WI-FI ONE, LLC v. BROADCOM CORP. 19

III
Wi-Fi also challenges the Board’s determination that
Seo anticipates the ’215 patent. Wi-Fi makes three sepa-
rate arguments: (1) that Seo does not disclose a “type
identifier field”; (2) that Seo does not disclose a type
identifier field within a message field; and (3) that the
Board misconstrued the term “type identifier field.”
A
Claim 1 of the ’215 patent, which is representative,
provides as follows:
A method for minimizing feedback responses in an
ARQ protocol, comprising the steps of:
sending a plurality of first data units over a
communication link;
receiving said plurality of first data units; and
responsive to the receiving step, constructing
a message field for a second data unit, said
message field including a type identifier field
and at least one of a sequence number field, a
length field, and a content field.
Wi-Fi argues that Seo does not disclose a type identi-
fier field because it discloses only a single type of mes-
sage, and the single type of message contains fields for
encoding errors as both lists and bitmaps. Wi-Fi relies on
Figure 4 of Seo, shown below:
20 WI-FI ONE, LLC v. BROADCOM CORP.

Based on Figure 4, Wi-Fi argues that the data struc-
ture in Seo contains fields for the list type of coding,
which are entitled FIRST, LAST, FCS, and PADDING,
and fields for the bitmap type of coding, which are enti-
tled NAK_Map_Count, NAK_Map_SEQ, and NAK_Map.
Wi-Fi argues that in Seo all fields are always present,
either as useful values or as “padded zeros,” i.e., place-
holders, regardless of the value of the NAK_TYPE field.
Therefore, Wi-Fi argues, the NAK_TYPE field does not
function as a type identifier field that identifies the type
of coding used in Seo’s data structure.
WI-FI ONE, LLC v. BROADCOM CORP. 21

The Board rejected that argument, relying on the dis-
closure in Seo that certain fields “exist” depending on the
value of the NAK_TYPE field. See Seo, col. 5, ll. 54-57
(“When a value of the field NAK_TYPE is ‘00’, the receiv-
ing station requests a retransmission of missed user data
frames numbered a field FIRST through a field LAST.”);
col. 6, ll. 18-22 (“If a value of the field NAK_TYPE is ‘01’,
the field NAK_MAP_COUNT exi[s]ts.”). Based on those
portions of the Seo specification, the Board concluded that
Seo discloses a control frame “that includes certain fields
only when NAK_TYPE is ‘00’ and includes other fields
only when NAK_TYPE is ‘01.’” Accordingly, the Board
rejected Wi-Fi’s argument that NAK_TYPE is not a type
identifier field.
The Board also credited the testimony of Broadcom’s
expert that it would not make sense to include unneces-
sary fields in a message. It was entirely reasonable for
the Board to read the term “exist” in Seo in that way.
Substantial evidence therefore supports the Board’s
conclusion that Seo discloses the type identifier field
feature recited in the ’215 patent.
B
Wi-Fi also argues that even if Seo discloses a type
identifier field, Seo does not anticipate the ’215 patent,
because the NAK_TYPE field in Seo is part of the S-PDU
header rather than the message field, as required by the
claims.
The Board rejected that argument, finding that the
’215 patent does not require the type identifier field to be
in any particular part of the message, and that, in any
event, Seo’s NAK_TYPE field was included in the mes-
sage field. We agree with the Board. Nothing in the ’215
patent specifies whether the type identifier field must be
located in the header or any other specific part of the
message.
22 WI-FI ONE, LLC v. BROADCOM CORP.

Wi-Fi also argues that a prior amendment to claim 1
shows that the claim is drawn to the distinction between
the message body and the header. During the prosecution
of the ’215 patent, Wi-Fi offered the following amend-
ment:
said message field including a type identifier field
and at least one of a type identifier field, a se-
quence number field, a length field, and a content
field.
That amendment moved the type identifier field from
being one of four optional fields to being a required field,
accompanied by at least one of the three remaining op-
tional fields.
On appeal, Wi-Fi argues that the amendment “distin-
guish[es], among other things, fields that were included in
the header of the PDU such as the ‘PDU_format’ field
shown in the admitted prior art.” That argument is
meritless. The type identifier field was identified as part
of the message field before and after the amendment, so
the amendment had no effect on where in the packet the
type identifier field had to be located. The amendment
simply made that term a required feature, rather than
one of the options listed in the “at least one” clause.
That understanding is confirmed by the applicants’
remarks accompanying the amendment. The applicants
distinguished a prior art reference by stating that amend-
ed claim 1 “provides the type identifier field and at least
one of a sequence number field, a length field, and a
content field.” Because there is no support in the patent
or the prosecution history for Wi-Fi’s distinction between
the presence of the type identifier field in the message
field and in the header, the Board was correct to reject
Wi-Fi’s argument.
WI-FI ONE, LLC v. BROADCOM CORP. 23

C
Wi-Fi next argues that the Board erred in construing
the term “type identifier field” in the phrase “responsive
to the receiving step, constructing a message field for a
second data unit, said message field including a type
identifier field” to mean “a field of a message that identi-
fies the type of that message.” Wi-Fi argues that the
Board’s construction failed to specify that a type identifier
field must distinguish the type of message from a number
of different message types.
We agree with the Board that Wi-Fi’s interpretation
does no more than restate what is already clear from the
Board’s construction—that a type identifier field must
distinguish between different message types. Wi-Fi’s real
quarrel is not with the Board’s claim construction, but
with the Board’s conclusion that Seo discloses different
message types. As we have noted, the Board’s conclusion
that Seo discloses different message types is supported by
substantial evidence.
IV
Wi-Fi challenges the Board’s analysis of claim 15.
That claim reads:
A method for minimizing feedback responses in an
ARQ protocol, comprising the steps of:
sending a plurality of first data units over a
communication link;
receiving said plurality of first data units; and
responsive to the receiving step, constructing
a message field for a second data unit, said
message field including a type identifier field
and at least one of, a length field, a plurality
of erroneous sequence number-fields, and a
plurality of erroneous sequence number
length fields, each of said plurality of errone-
24 WI-FI ONE, LLC v. BROADCOM CORP.

ous sequence number fields associated with a
respective one of said plurality of erroneous
sequence number length fields.
Wi-Fi argues that claim 15, properly construed, re-
quires that the message field contain either a “length
field” or an “erroneous sequence number length field.”
Because Seo does not disclose length fields of either type,
Wi-Fi argues that it does not anticipate claim 15.
Wi-Fi’s argument is based on the structure of the “at
least one of” clause. That clause requires that at least one
of the following be present: “a length field,” “a plurality of
erroneous sequence number fields,” or “a plurality of
erroneous sequence number length fields.” The second
entry on the list, “a plurality of erroneous sequence-
number fields,” is not by itself a type of length field.
However, the final clause of that limitation provides “each
of said plurality of erroneous sequence number fields
associated with a respective one of said plurality of erro-
neous sequence number length fields.” That clause, Wi-Fi
argues, requires that each erroneous sequence number
field must be associated with an erroneous sequence
number length field. For that reason, Wi-Fi contends that
some sort of length field is required to meet claim 15.
Broadcom argues that the “each of said” clause re-
quires that each of the erroneous sequence number length
fields must be associated with an erroneous sequence
number field, not the other way around. Therefore, in
Broadcom’s view, an erroneous sequence number field can
stand alone, without an accompanying erroneous se-
quence number length field; for that reason, according to
Broadcom, claim 15 does not require the presence of a
length field in all cases.
Wi-Fi’s is the better reading of the text of the claim.
The structure of the “at least one of” limitation is best
understood by stripping it to its essence: substituting A
for the length field, B for the plurality of erroneous se-
WI-FI ONE, LLC v. BROADCOM CORP. 25

quence number fields, and C for the erroneous sequence
number length fields. So viewed, the claim by its terms
would require one of A, B, or C, except that each of B
must be associated with one of C. That reading is at odds
with Broadcom’s, which would require each of C to be
associated with one of B.
While the text of the limitation, standing alone, favors
Wi-Fi’s interpretation, we conclude that Wi-Fi’s interpre-
tation does not make sense in light of the specification,
and thus that Broadcom’s interpretation must be accepted
as correct.
The specification of the ’215 patent explains the prop-
erties and purpose of the length field. The length field is
used in open-ended data structures to provide information
about the data structure, such as the number of lists or
bitmaps that are present in a packet, or the length of the
bitmaps that are used to represent errors. See ’215 pa-
tent, col. 2, ll. 56-62; col. 6, ll. 25-34; col. 7, ll. 52-65.
Because the length of a particular message can be fixed
by the rules of the protocol, a length field is not a required
feature of the invention. See id., col. 7, ll. 57-60 (“For this
exemplary embodiment, each such message includes a
type identifier, and the length is either fixed or indicated
by a length field for each specific message.”).
The specification also describes the purpose of the er-
roneous sequence number fields and the erroneous se-
quence number length fields. The specification explains
that one method for representing errors “is to include a
field after each list element which determines the length
of the error, instead of indicating the length of the error
with an ‘ending’ [sequence number].” Id., col. 7, ll. 31-33.
Using that method, strings of consecutive errors are
represented with an erroneous sequence number that
marks the beginning of the error, followed by an errone-
ous sequence number length field that marks how long
the error persists. That method is generally more effi-
26 WI-FI ONE, LLC v. BROADCOM CORP.

cient than representing an error sequence by its starting
and ending point because “[i]n most systems, the size of
the length field would then be substantially smaller than
the size of the [sequence number] field.” Id., col. 7, ll. 33-
35.
Figure 9 of the ’215 patent shows how that method
would represent the failed transmission of a series of
packets numbered 51-77:

The erroneous sequence number field, SN1, shows that
the error sequence begins at sequence number 51. The
erroneous sequence number length field, L1, shows that
the error extends for 27 packets, covering packets 51
through 77.
Based on those descriptions of embodiments of the in-
vention, it is clear that an erroneous sequence number
length field is useful only when it is paired with an erro-
neous sequence number field, while an erroneous se-
quence number field can be useful without an
accompanying erroneous sequence number length field.
Thus, an erroneous sequence number field can stand
alone, but an erroneous sequence number length field
cannot.
The ’215 specification makes clear that an erroneous
sequence number field can be used absent an erroneous
WI-FI ONE, LLC v. BROADCOM CORP. 27

sequence number length field. As examples, Figure 10
shows four erroneous sequence numbers that are used to
indicate errors, and Figure 12 shows a bitmap that con-
tains an erroneous sequence number field to indicate
where the bitmap begins. Both contain erroneous se-
quence number fields, but not erroneous sequence number
length fields, thus supporting the Board’s construction of
claim 15.
By contrast, an erroneous sequence number length
field can indicate an error only by reference to a starting
point, which would be represented by an erroneous se-
quence number field. The ’215 patent discloses no exam-
ples of an erroneous sequence number length field
without an accompanying erroneous sequence number
field, for the simple reason that an erroneous sequence
number length field standing alone would not convey
sufficient information to determine what packets must be
retransmitted.
Based on the full teaching of the specification, we con-
clude that Wi-Fi’s proposed construction of claim 15 is
unreasonable. It would allow an erroneous sequence
number length field to be present without an erroneous
sequence number field, which the specification indicates
would not work, while requiring all erroneous sequence
number fields to be associated with erroneous sequence
number length fields, which the patent teaches is not
necessary. The Board’s construction, on the other hand,
comports with what the patent teaches about the number
and length fields. Even though the language of claim 15,
standing alone, provides some support for Wi-Fi’s inter-
pretation, we hold that in the end the claim must be read
as the Board construed it in order to be faithful to the
invention disclosed in the specification.
Accordingly, claim 15, as properly construed, does not
require either a length field or a plurality of erroneous
sequence number length fields. Because Wi-Fi contends
28 WI-FI ONE, LLC v. BROADCOM CORP.

that Seo is distinguishable solely on the ground that it
does not require length fields of any type, we hold that the
Board was correct to conclude that Seo anticipates claim
15 of the ’215 patent.
Each party shall bear its own costs for this appeal.
AFFIRMED
 United States Court of Appeals
for the Federal Circuit
______________________

WI-FI ONE, LLC,
Appellant

v.

BROADCOM CORPORATION,
Appellee

ANDREI IANCU, UNDER SECRETARY OF
COMMERCE FOR INTELLECTUAL PROPERTY
AND DIRECTOR OF THE UNITED STATES
PATENT AND TRADEMARK OFFICE,
Intervenor
______________________

2015-1944
______________________

Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2013-
00601.
______________________

REYNA, Circuit Judge, dissenting.
In this appeal, the court for the first time defines the
legal standard for establishing “privity” under 35 U.S.C.
§ 315(b). The majority concludes that to establish privity,
a petitioner must have had control over the prior district
court litigation. This narrow standard will make it diffi-
cult for a patentee to successfully assert § 315(b). I be-
2 WI-FI ONE, LLC v. BROADCOM CORP.

lieve that control of a prior litigation is but one form of
privity. Privity may exist in other forms that do not
involve control over the prior litigation, all of which are
excluded under the standard adopted by the majority. I
respectfully dissent.
This court recently ruled en banc that § 315(b) time
bar determinations by the Patent Trial and Appeal Board
(“Board”) in inter partes review (“IPR”) proceedings are
appealable. Wi-Fi One, LLC v. Broadcom Corp., 878 F.3d
1364, 1375 (Fed. Cir. 2018) (en banc). Following that
ruling, the court remanded these three consolidated cases
to this panel to consider the merits of Wi-Fi One, LLC’s
(“Wi-Fi”) appeal of whether Broadcom Corporation’s
(“Broadcom”) petition is time barred, and whether Wi-Fi
is entitled to additional discovery on the § 315(b) issue.
The majority affirms the Board’s decision that Broad-
com’s petition is not time barred under § 315(b). The
majority rejects Wi-Fi’s argument that the Board applied
a legally erroneous standard in its privity analysis. The
majority affirms the Board’s decision that the applicable
legal standard is whether “the party in question had
sufficient control over the prior proceeding.” Maj. Op. at
17. The majority also concludes that the Board did not
abuse its discretion in denying Wi-Fi’s request for addi-
tional discovery. Maj. Op. at 16.
I depart from the opinion of my colleagues. I conclude
that the Board applied an erroneous standard for estab-
lishing privity, which in turn drove its decision to deny
further discovery. The Board’s denial of Wi-Fi’s motion
for additional discovery was therefore an abuse of discre-
tion. I would vacate the Board’s final written decision
with instruction that the Board permit limited, focused
discovery on the § 315(b) privity issue and thereafter
determine anew whether Broadcom’s petition is time
barred in accordance with the correct standard.
WI-FI ONE, LLC v. BROADCOM CORP. 3

I. PRIVITY
In 2010, Wi-Fi’s predecessors-in-interest, Ericsson,
Inc. and Telefonaktiebolaget LM Ericsson (collectively
“Ericsson”), filed its complaint for infringement of U.S.
Patent Nos. 6,772,215 (“’215 patent”), 6,466,568 (“’568
patent”), and 6,424,625 (“’625 patent”) in the United
States District Court for the Eastern District of Texas
against multiple defendants (“the Texas Litigation”). See
Ericsson Inc. v. D-Link Sys., Inc., No. 6:10-CV-473, 2013
WL 4046225, at *24 n.1 (E.D. Tex. Aug. 6, 2013), aff’d in
part, vacated in part, rev’d in part, 773 F.3d 1201 (Fed.
Cir. 2014). The case progressed to a jury trial, where the
jury found that the defendants infringed the asserted
claims. Broadcom, the appellee here, was not a named
defendant in the Texas Litigation. In 2013, three years
after the defendants in the Texas Litigation were served
with complaints for infringement, Broadcom filed three
separate petitions for IPR of the three patents.
During the pre-institution phase, Wi-Fi sought to bar
institution of Broadcom’s IPRs. Wi-Fi argued that Broad-
com “is subject to the 35 U.S.C. § 315(b) bar as a privy to”
the defendants of the Texas Litigation initiated three
years before the filing of Broadcom’s petitions. J.A. 144.
Wi-Fi argued that privity could exist on multiple inde-
pendent grounds: substantive legal relationship between
Broadcom and the Texas Litigation defendants, Broad-
com’s control over the Texas Litigation, and the defend-
ants’ collusion in filing of the IPR petitions. J.A. 46, 49–
50. However, the Board limited its privity analysis to a
single ground. The Board repeatedly stated that in order
to find privity, Wi-Fi had to show that Broadcom had
control over the Texas Litigation. “To be bound [to the
outcome of the Texas Litigation], in normal situations,
Broadcom must have had control over the Texas Litiga-
4 WI-FI ONE, LLC v. BROADCOM CORP.

tion.” Broadcom Corp. v. Wi-Fi One, LLC, No. IPR2013-
00601, Paper No. 23, at 7 (P.T.A.B. Mar. 6, 2015) (empha-
sis added); J.A. 81. 1 Applying this standard, the Board
rejected Wi-Fi’s motion for additional discovery because
Wi-Fi’s evidence and arguments failed to show that
“Broadcom controlled or could have controlled the Texas
Litigation.” J.A. 89.
Wi-Fi appeals and argues that “[t]he Board committed
a critical and serious legal error” in making its § 315(b)
determination by “appl[ying] a narrow and rigid legal
standard that focused exclusively on whether Broadcom
has a right to control the District Court Litigation.”
Appellant Br. at 31, 34. Wi-Fi argues that “[t]he Board’s
erroneous legal standard undermines both the plain text
and purpose of § 315(b).” Id. at 35. The majority avoids
Wi-Fi’s precise argument on appeal, endorses the Board’s
narrow standard for proving privity under § 315(b), and
affirms the Board’s finding of no privity between Broad-
com and the Texas Litigation defendants because “[t]here

1 See also J.A. 85 (“The totality of the evidence fails
to amount to more than a ‘mere possibility’ that Broadcom
controlled, or could have controlled, the Texas litigation.”)
(emphasis added); J.A. 87 (“[T]he IPR filings fail to show
control over the Texas Litigation. The evidence does not
amount to more than speculation that any of Broadcom’s
activity constitutes evidence of collusion with the D-Link
defendants in the Texas Litigation in a manner that
would bind Broadcom to the outcome thereof.”) (emphasis
added); J.A. 89 (“The evidence and arguments fail to show
that the sought-after discovery would have more than a
mere possibility of producing useful privity information,
i.e., that Broadcom controlled or could have controlled the
Texas Litigation.”) (emphasis added).
WI-FI ONE, LLC v. BROADCOM CORP. 5

was no such showing of control in this case.” Maj. Op. at
18.
I disagree. The Board’s narrow and rigid “control over
the prior litigation” requirement contravenes precedent
from the Supreme Court and this court, impermissibly
cabins the privity inquiry into only one factor—control of
the prior litigation—and ignores other relevant factors. It
fails to account for the complexities of the marketplace
and the infinite number of business forms and relation-
ships that entities assume to achieve common purpose.
The term “privity” is not defined in the Leahy-Smith
America Invents Act (“AIA”). I agree with the majority
that Congress intended to adopt common law principles of
“privy” and “real party in interest” when it drafted the
AIA. Maj. Op. at 8 (citing 154 Cong. Rec. S9987 (daily ed.
Sept. 27, 2008) (statement of Sen. Kyl)). Congress did not
leave to the U.S. Patent and Trademark Office’s (“PTO”)
discretion to determine the legal standards for “privity”; it
is a question well within the province of the judiciary. See
U.S. Bank Nat’l Ass’n ex rel. CWCapital Asset Mgmt. LLC
v. Vill. at Lakeridge, LLC, 138 S. Ct. 960, 967 (2018)
(finding appellate courts should apply de novo review
when “elaborating on a broad legal standard” because of
“‘institutional advantages’ in giving legal guidance”
(quoting Salve Regina College v. Russell, 499 U.S. 225,
231–33 (1991))); Princeton Vanguard, LLC v. Frito-Lay N.
Am., Inc., 786 F.3d 960, 964 (Fed. Cir. 2015) (“Whether
the Board applied the correct legal standard . . . is a
question of law we review de novo.”); McDonnell Douglas
Corp. v. United States, 323 F.3d 1006, 1014 (Fed. Cir.
2003) (holding that “determination of legal standards is a
pure issue of law” that we review de novo).
The general definition of privity is “[t]he connection or
relationship between two parties, each having a legally
recognized interest in the same subject matter (such as a
transaction, proceeding, or piece of property).” Privity,
6 WI-FI ONE, LLC v. BROADCOM CORP.

Black’s Law Dictionary (10th ed. 2014). Generally, one is
not bound by a judgment “in a litigation in which he is not
designated as a party or to which he has not been made a
party by service of process.” Hansberry v. Lee, 311 U.S.
32, 40 (1940). However, this rule is subject to important
exceptions where the judgment would preclude a nonpar-
ty from relitigating the same claims and issues in another
forum. See Taylor v. Sturgell, 553 U.S. 880, 893 (2008).
The term “privity” is used broadly “as a way to express
the conclusion that nonparty preclusion is appropriate on
any ground.” Id. at 894 n.8; Richards v. Jefferson Cty.,
Ala., 517 U.S. 793, 798 (1996) (same); Int’l Nutrition Co.
v. Horphag Research, Ltd., 220 F.3d 1325, 1329 (Fed. Cir.
2000) (stating that the term privity “is simply a short-
hand way of saying that [a] nonparty [i.e., a party not
named in a prior action] will be bound by the judgment in
that action”).
In a unanimous opinion, the Supreme Court in Taylor
described a non-exhaustive list of six categories where
each alone is sufficient to establish privity between a
named party and a nonparty in litigation: (1) an agree-
ment between the parties to be bound; (2) pre-existing
substantive legal relationships between the parties; (3)
adequate representation by the named party; (4) the
nonparty’s control of the prior litigation; (5) where the
nonparty acts as a proxy for the named party to relitigate
the same issues; and (6) where special statutory schemes
foreclose successive litigation by the nonparty (e.g., bank-
ruptcy and probate). 553 U.S. at 894–95. The Supreme
Court noted that this list of six categories “is meant only
to provide a framework” for considering privity, “not to
establish a definitive taxonomy.” Id. at 893 n.6.
The PTO’s Trial Practice Guide is consistent with
Taylor. Office Patent Trial Practice Guide, 77 Fed. Reg.
48,756 (Aug. 14, 2012). The Trial Practice Guide provides
that the PTO “intends to evaluate what parties constitute
‘privies’ in a manner consistent with the flexible and
WI-FI ONE, LLC v. BROADCOM CORP. 7

equitable considerations established under federal
caselaw.” Id. at 48,759. The Trial Practice Guide adopts
Taylor’s definition for privity: “[p]rivity is essentially a
shorthand statement that collateral estoppel is to be
applied in a given case . . . . The concept refers to a
relationship between the party to be estopped and the
unsuccessful party in the prior litigation which is suffi-
ciently close so as to justify application of the doctrine of
collateral estoppel.” Id. (citations omitted); see Taylor,
553 U.S. at 894 n.8 (“The term ‘privity,’ however, has also
come to be used more broadly, as a way to express the
conclusion that nonparty preclusion is appropriate on any
ground.”).
Based on the record before the Board, at minimum
three of the six Taylor grounds—the second, fourth and
fifth—are implicated in this case. First, privity can be
found when there is a substantive legal relationship
between the parties. Taylor, 553 U.S. at 894. For exam-
ple, as this court has observed, nonparty preclusion is
warranted when an indemnitor participates in defending
an action brought against its indemnitee. Intel Corp. v.
U.S. Int’l Trade Comm’n, 946 F.2d 821, 839 (Fed. Cir.
1991) (finding that “an indemnification agreement, in
other cases, has alone been enough to find privity”); see
also SpeedTrack, Inc. v. Office Depot, Inc., No. C 07–3602
PJH, 2014 WL 1813292, at *6–7 (N.D. Cal. May 6, 2014)
(ruling that in view of the indemnification obligations the
manufacturer owed to its customer, the manufacturer was
in privity with the customer such that claim preclusion
could apply), aff’d, 791 F.3d 1317, 1324–29 (Fed. Cir.
2015). In cases involving indemnification agreements, the
indemnitor operates like an insurer who indemnifies the
insured—the indemnitee—and when the indemnitor has
paid the entire claim to the indemnitee, he is subrogated
to the rights of the indemnitee and becomes the real party
in interest. See 18A Charles Alan Wright, Arthur R.
Miller & Edward H. Cooper, Federal Practice and Proce-
8 WI-FI ONE, LLC v. BROADCOM CORP.

dure § 1546 (2d ed. 2011) (hereinafter “Wright & Miller”).
In this regard, the indemnitor stands in the shoes of the
indemnitee. Thus, I disagree with the majority’s en-
dorsement of the Board’s finding that an indemnification
provision cannot be indicative of privity or real-party-in-
interest status. Maj. Op. at 15–16. Indemnification
agreements alone may not always mandate a finding of
nonparty preclusion, but their existence is strong evidence
for privity and, at minimum, presents an independent
basis that warrants additional discovery into the terms of
these agreements and the parties’ actions pursuant to the
agreements.
Wi-Fi discovered that Broadcom had indemnification
agreements pertaining to the infringing products with
some Texas Litigation defendants during IPR. Indeed,
Broadcom supplied the Texas Litigation defendants the
very chipsets that formed the basis for the infringement
allegations in the Texas Litigation. Broadcom does not
deny the existence of the indemnification agreements, nor
contest whether they pertained to the accused products.
Rather, Broadcom reported in its SEC filings that it is not
uncommon for Broadcom to be “required to indemnify
some customers and strategic partners under our agree-
ments if a third party alleges or if a court finds that our
products or activities have infringed upon, misappropriat-
ed or misused another party’s proprietary rights.” J.A.
190–91. The Board acknowledged that the district court
in the Texas Litigation mentioned “two indemnity agree-
ments and an e-mail communication about indemnity.”
J.A. 84. Wi-Fi also alleges that Broadcom assisted de-
fendants during the Texas Litigation, and provided analy-
sis of the “very patents that are now the subject of
Broadcom’s [IPR] petitions.” J.A. 45–46.
Citing Taylor, Wi-Fi argued that indemnity agree-
ments constitute a substantive legal relationship suffi-
cient under the second category of Taylor to establish
privity in its motion for additional discovery. Wi-Fi
WI-FI ONE, LLC v. BROADCOM CORP. 9

proffered concrete evidence of a substantive legal rela-
tionship between Broadcom and the prior defendants, and
its position cannot be said to be mere “speculation” or
“conjecture.” J.A. 90. The evidence suggests that the
relationship between Broadcom and the Texas Litigation
defendants went beyond typical transactions between
supplier and buyer. Based on this evidence, Wi-Fi sought
limited additional discovery on the terms of the indemni-
fication agreements, but was rejected by the Board. This
denial was in error. The terms of indemnity agreements
between Broadcom and the Texas Litigation defendants
are important to determine the relationship between
Broadcom and the Texas Litigation defendants. Depend-
ing on the agreements’ terms and whether Broadcom has
paid claims to the defendants pursuant to the court’s
judgment in the Texas Litigation, the indemnification
agreements would create a substantive legal relationship
between Broadcom and the Texas Litigation defendants,
potentially barring the PTO under § 315(b) from institut-
ing Broadcom’s IPRs. See Intel, 946 F.2d at 839; Speed-
Track, 2014 WL 1813292, at *6–7.
Second, privity can also be found when a nonparty
“assume[d] control” over the litigation in which that
judgment was rendered. Taylor, 553 U.S. at 895 (citing
Montana v. United States, 440 U.S. 147, 154 (1979)). The
rationale for this ground of nonparty preclusion is that
since the nonparty has had “the opportunity to present
proofs and argument,” he has already “had his day in
court” even though he was not a named party to the
litigation. Id. (quoting Restatement (Second) of Judg-
ments § 39 cmt. a). To determine whether privity exists
between parties, “all contacts between [the parties], direct
and indirect, must be considered.” Intel, 946 F.2d at 838.
Although whether the nonparty exercised or could have
exercised control over a party’s participation in a proceed-
ing is a “common consideration” for a privity inquiry, the
PTO’s Trial Practice Guide explicitly states that “[c]ourts
10 WI-FI ONE, LLC v. BROADCOM CORP.

and commentators agree, however, that there is no
‘bright-line test’ for determining the necessary quantity or
degree of participation to qualify as a ‘real party-in-
interest’ or ‘privy’ based on the control concept.” 77 Fed.
Reg. at 48,759 (emphases added).
The evidence before the Board shows that Broadcom
was more than a bystander to the Texas Litigation.
Broadcom has a corporate policy on litigation on behalf of
its customers, including an undisputed contractual obliga-
tion to indemnify the Texas Litigation defendants. J.A.
84. Broadcom’s SEC filings report that to protect inter-
ests of its indemnified “customers and strategic partners,”
Broadcom “engage[s] in litigation to . . . determine the
validity and scope of the proprietary rights of others,
including [its] customers.” J.A. 45. Wi-Fi also proffered
evidence that Broadcom coordinated with the defendants
in the Texas Litigation, which may have assisted Broad-
com in the filing of the IPRs. J.A. 45–47, 50. In addition,
Broadcom filed an amicus brief in the appeal from the
Texas Litigation supporting the defendants. While the
Texas Litigation was pending, Broadcom argued in an-
other forum that the assertion of Wi-Fi’s patents was
anticompetitive, demonstrating that Broadcom had direct
business interests implicated in the Wi-Fi patents assert-
ed in the Texas Litigation. Thus, while the evidence so
far may not be sufficient to establish the extent of control
that Broadcom had in the Texas Litigation, the evidence
is sufficient to warrant additional discovery concerning
Broadcom’s control over the Texas Litigation defendants.
In my view, discovery is required for the Board to proper-
ly assess the degree of Broadcom’s involvement in the
Texas Litigation. See Intel, 946 F.2d at 838.
Finally, a party bound by a judgment cannot escape
preclusion by relitigating the same issues through a
nonparty proxy. Taylor, 553 U.S. at 895 (recognizing that
a nonparty cannot “later bring[] suit as the designated
representative of a person who was a party to the prior
WI-FI ONE, LLC v. BROADCOM CORP. 11

adjudication”). This concept is similar to real party in
interest. The typical common law expression of real party
in interest indicates a party “who, according to the gov-
erning substantive law, is entitled to enforce the right.”
See Wright & Miller § 1543 (discussing Fed. R. Civ. P. 17).
This notion reflects standing concepts that do not fit
directly in the America Invents Act trial context because
there is no standing requirement for a petitioner to file an
IPR. The PTO interprets real party in interest as “the
party that desires review of the patent” and “may be the
petitioner itself, and/or it may be the party or parties at
whose behest the petition has been filed.” 77 Fed. Reg. at
48,759.
Wi-Fi contends that the Texas Litigation defendants
are the real parties in interest in Broadcom’s IPRs. In
support, Wi-Fi alleges evidence that suggested collusion
between the defendants and Broadcom in the filing of the
petitions. For example, Broadcom’s petitions relied on
Ericsson’s (Wi-Fi’s predecessor-in-interest) expert report
from the Texas Litigation—a report that Broadcom alleg-
edly could only have obtained from one of the defendants.
Broadcom’s IPR petitions also recited the same prior art
references used by the defendants in the Texas Litigation,
as the Board acknowledged, again suggesting collusion
between Broadcom and the defendants. Before the Board,
Wi-Fi sought discovery of communications between
Broadcom and the defendants relating to the filing of the
IPRs. Under the facts of this case, and in view of Taylor,
Wi-Fi provided the Board with sufficient evidence to
support its privity allegations and the Board abused its
discretion by denying Wi-Fi’s request for discovery.
In face of a fact pattern that calls into question multi-
ple Taylor categories—substantive legal relationships,
control of the prior litigation, and relitigating by proxy—
the Board applied a “control over the prior litigation” test
for privity that is impermissibly narrow. The Board
concluded that “[t]o be bound [to the outcome of the Texas
12 WI-FI ONE, LLC v. BROADCOM CORP.

Litigation], in normal situations, Broadcom must have
had control over the Texas Litigation.” J.A. 81 (emphasis
added). The Board’s narrow application is inconsistent
with Taylor and the PTO’s Trial Practice Guide. By
concluding “[p]aying for trial expenses pursuant to in-
demnity normally does not establish privity or control,”
the Board failed to recognize that substantive legal rela-
tionship under Taylor is a separate ground for privity
from control over prior litigation, and is not merely a
circumstance to establish the latter. J.A. 85. The Board
cited a few cases from other circuits and district courts to
support its proposition, J.A. 81–83, but these cases pre-
dated Taylor and do not stand for the proposition that
privity can only be satisfied if the petitioner controls the
district court litigation. At most, these cases demonstrate
that when a party has had control over a prior litigation,
privity can be found, an outcome that is consistent with
Taylor’s fourth category.
Privity, therefore, can exist in situations where a par-
ty has not had direct control over a prior litigation, as
outlined by Taylor and acknowledged by the PTO. 77
Fed. Reg. at 48,759 (“There are multiple factors relevant
to the question of whether a non-party may be recognized
as a ‘real party-in-interest’ or ‘privy.’” (emphasis added)).
Hence, the majority reaches the incorrect conclusion that
the Board’s legal standard for privity analysis “is con-
sistent with general legal principles.” 2 Maj. Op. at 9.

2 The majority justifies its narrow holding on
grounds that Wi-Fi did not raise other Taylor grounds
before the Board and that Wi-Fi limited its argument to
the “control over the prior litigation” ground. Maj. Op. at
12 n.3. This is incorrect. In its motion for additional
discovery, Wi-Fi argued that Taylor is the legal standard
and it sets out the six categories for determining whether
WI-FI ONE, LLC v. BROADCOM CORP. 13

In deciding whether privity exists under § 315(b), the
Board should start with a review of the six grounds of
privity set forth in Taylor and consider all the facts and
circumstances for each ground. Among the factors that
the Board should consider are: (1) whether there exists a
substantive legal relationship between the parties and the
nature of that relationship; (2) whether the petitioner and

a nonparty to a suit is bound by a prior judgment. J.A.
49. Wi-Fi explicitly argued that privity could found on
multiple grounds: substantive legal relationships based
on indemnification agreements, Broadcom’s control over
the Texas Litigation, and the defendants’ collusion in
filing of the IPR petitions. J.A. 46, 49–50. For example,
Wi-Fi argued that “[o]ne [Taylor] category asks whether
the nonparty maintains a ‘substantive legal relationship’
with a party in suit” and that “[t]he weight of authority
strongly supports that an indemnity agreement consti-
tutes a substantive legal relationship sufficient to estab-
lish privity.” J.A. 49, 50. Wi-Fi repeats the allegation
that the Board applied an erroneous legal standard in the
instant appeal. See Appellant Br. at 31. It is well-
established that a litigant has a “right to have all issues
fully considered and ruled on by the appellate court.”
Bernklau v. Principi, 291 F.3d 795, 801 (Fed. Cir. 2002)
(citing United States v. Garza, 165 F.3d 312, 314 (5th Cir.
1999)). Although this does not equate to a right to a full
written opinion on every issue raised, this court should
not avoid addressing the very question on appeal: what is
the legal standard for establishing that a petition is time
barred under § 315(b)? This is particularly true where, as
here, we review for the first time the legal standard for
privity under § 315(b), a question that naturally rises
from our en banc decision holding that this court has
jurisdiction to review § 315(b) determinations. Wi-Fi One,
878 F.3d at 1375.
14 WI-FI ONE, LLC v. BROADCOM CORP.

an accused infringer in a prior litigation have worked in
concert in that litigation; and (3) whether the petitioner
and the accused infringer in the prior litigation have
worked in concert to file the IPR petition. 3
Substantive legal relationships may take a variety of
forms, including, but not limited to, subsidiary and parent
company, joint venture, preceding and succeeding owners
of property, bailee and bailor, assignee and assignor,
indemnitee and indemnitor, and subrogee and subrogor.
See Taylor, 553 U.S. at 894. For example, the relation-
ship between parties may extend beyond that of typical
suppliers and buyers, such that the parties are stakehold-
ers engaged in a common enterprise. In such instances, a
substantive legal relationship may exist and privity may
be established. Further, a petitioner’s participation in the

3 The use of “prior litigation” does not imply that
the prior district court action must be resolved or reach a
judgment for the purpose of the time bar under § 315(b).
Section 315(b) states that “[a]n inter partes review may
not be instituted if the petition requesting the proceeding
is filed more than 1 year after the date on which the
petitioner, real party in interest, or privy of the petitioner
is served with a complaint alleging infringement of the
patent.” 35 U.S.C. § 315(b) (emphasis added). Once a
complaint of infringement is served, the petitioner, real
party in interest, or privy of the petitioner has a statutory
one year period to file an IPR from the date of service.
Nothing in § 315(b) indicates that the outcome of the
district court litigation affects the time bar determina-
tions. The time bar applies regardless if the prior litiga-
tion is still ongoing at the end of the one year period, or if
the parties settle before that date.
WI-FI ONE, LLC v. BROADCOM CORP. 15

prior litigation can take a variety of forms, such as:
whether the petitioner participated, directly or indirectly,
in the prior litigation and the extent of the participation;
whether the petitioner controlled, or had opportunity to
control the prior litigation; and whether the petitioner
provided funding for or was obliged to fund the prior
litigation. Similarly, an accused district court litigation
infringer’s participation in the filing of the IPR petition
via a nonparty proxy, such as whether the accused in-
fringer participated, controlled, or funded the filing of the
IPR petition, directly or indirectly, could lead to a finding
that the petitioner is in privity with the accused infringer.
II. DISCOVERY
Relying on an erroneous standard of privity, the
Board abused its discretion when it denied Wi-Fi’s motion
for additional discovery. The Board gave two reasons for
denying Wi-Fi’s motion for additional discovery. First,
the Board cautioned that “without some evidence of actual
control of a trial,” the discovery could “spiral into what
amounts to a separate trial that involves a myriad of
considerations.” J.A. 89. The Board also suggested that a
restrictive standard for additional discovery is required,
or anything less would “impact[] the PTAB’s mandate to
expedite the proceedings and provide limited discovery in
the interests of justice.” Id.
The Board’s first ground fails because the record of
this case amply supports granting Wi-Fi’s motion for
additional discovery. First, Wi-Fi’s request amounts to
more than a “mere possibility” or “mere allegation that
something useful [to the proceeding] will be found.” J.A.
80. Wi-Fi has asserted the existence of concrete evidence,
which Broadcom does not dispute. Second, Wi-Fi’s discov-
ery request was limited in scope and focused only on the
privity claims. And third, the requested discovery, if
proven to be true, would likely establish privity between
Broadcom and the Texas Litigation defendants.
16 WI-FI ONE, LLC v. BROADCOM CORP.

The inquiry into privity is highly fact-dependent, and
the Board should not be overly restrictive in granting
discovery motions. See Intel, 946 F.2d at 838 (holding
that “all contacts between [the parties], direct and indi-
rect, must be considered”). As discussed above, each
Taylor ground alone may be sufficient to establish privity
and thus bar the institution of the IPR. Privity can also
be inferred if circumstantial evidence supports collusion
or a substantive legal relationship between the parties.
This is particularly relevant because evidence of privity
often involves confidential commercial agreements that
are not publically available. 4 Parties often take steps to
conceal their relationship and in so doing hide the identi-
ty of the actual stakeholder(s). Additional discovery
should only be denied when a patentee fails to concretely
identify evidence implicating at least one Taylor factor, or
when the allegation of privity, if taken as true, cannot
establish a single Taylor factor.
Wi-Fi’s motion for additional discovery should be
granted because the record shows that the relationship
between Broadcom and the Texas Litigation defendants
went beyond a typical supplier/buyer relationship; Wi-Fi
alleged factual evidence to support its discovery request;
and most of Wi-Fi’s requested evidence, such as the
indemnification agreements (the existence of which is not
disputed by Broadcom) are easy to produce and cannot be
otherwise obtained. When viewed in aggregate, Wi-Fi’s
showing established a strong basis for allowing discov-
ery. 5

4 Broadcom and the Texas Litigation defendants re-
fused to waive confidentiality with regard to the indemni-
fication agreements before the Board. J.A. 51.
5 Wi-Fi sought to discover contracts between the
parties, especially the terms of the indemnification
WI-FI ONE, LLC v. BROADCOM CORP. 17

The Board’s expediency ground also fails. The Board
notes that given the statutory deadlines for issuing final
written decisions in IPRs, the Board “must be conserva-
tive in authorizing additional discovery.” J.A. 80. How-
ever, the desire to expedite the proceedings cannot come
at the cost of justice. Sackett v. EPA, 566 U.S. 120, 130
(2012) (repudiating “the principle that efficiency of regu-
lation conquers all”). Importantly, a fundamental statu-
tory purpose of § 315(b) is to “govern[] the relation of IPRs
to other proceedings or actions, including actions taken in
district court,” and to “set[] limits on the [PTO] Director’s
statutory authority to institute, balancing various public
interests.” Wi-Fi One, 878 F.3d at 1374.
As a threshold issue prior to institution, time bar de-
terminations are vital because IPRs can deprive a patent-
ee of significant property rights though the cancellation of
patents, as happened in this case. Although the statute
imposes no standing requirement on who may file a
petition, § 315(b) attests that the doors to IPR institution
are not open to every would-be petitioner. As this court
noted en banc, § 315(b) protects both the integrity and
efficiency of the IPR process by giving the Director of the
PTO an important tool to refuse institution. Wi-Fi One,
878 F.3d at 1374. The restrictive standard adopted by the
majority dulls that tool and defeats the purpose of
§ 315(b). For these reasons, I respectfully dissent.

agreements, records of invoices and payments between
them pursuant to the indemnification agreements, and
communications relating solely to the Texas Litigation
and the IPRs. The Board may limit the scope of addition-
al discovery.