  United States Court of Appeals
      for the Federal Circuit
                 ______________________

               CISCO SYSTEMS, INC.,
                     Appellant

                                v.

                   TQ DELTA, LLC,
                        Appellee
                 ______________________

                       2018-1806
                 ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2016-
01466.

           ----------------------------------------------

                 ARRIS GROUP, INC.,
                      Appellant

                                v.

                   TQ DELTA, LLC,
                        Appellee
                 ______________________

                       2018-1917
                 ______________________
2                        CISCO SYSTEMS, INC. v. TQ DELTA, LLC




    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2016-
01160.
                 ______________________

                 Decided: July 10, 2019
                 ______________________

    THEODORE M. FOSTER, Haynes & Boone, LLP, Dallas,
TX, argued for appellant Cisco Systems, Inc. Also repre-
sented by DAVID L. MCCOMBS, DEBRA JANECE MCCOMAS.

   DAN GRESHAM, Thomas Horstemeyer LLP, Atlanta,
GA, argued for appellant ARRIS Group, Inc. Also repre-
sented by CHARLES GRIGGERS, WESLEY AUSTIN ROBERTS.

   RAJENDRA A. CHIPLUNKAR, McAndrews, Held & Malloy,
Ltd., Chicago, IL, argued for appellee. Also represented by
PETER J. MCANDREWS.
                  ______________________

    Before NEWMAN, LINN, and WALLACH, Circuit Judges.
WALLACH, Circuit Judge.
     The instant appeal is the companion to concurrently is-
suing appeal No. 2018-1799, where we determined that
claims 6, 11, 16, and 20 of Appellee TQ Delta, LLC’s (“TQ
Delta”) U.S. Patent No. 8,611,404 (“the ’404 patent”) are
unpatentable as obvious over the same combination of
prior art analyzed in this appeal. See TQ Delta, LLC v.
Dish Network, LLC, No. 2018-1799, slip op. 19 (Fed. Cir.
July 10, 2019). We presume familiarity with our opinion
in related appeal, which recites the same technology and
illustrative claim as in the instant appeal, and we, there-
fore, recite only that which is necessary to understand the
issues on appeal here. See TQ Delta, slip op. 2–4,
CISCO SYSTEMS, INC. v. TQ DELTA, LLC                        3



     Appellant Cisco Systems, Inc. (“Cisco”) sought inter
partes review (“IPR”) with the U.S. Patent and Trademark
Office (“USPTO”) of claims 6, 10, 11, 15, 16, and 20 of the
’404 patent. Appellant ARRIS Group, Inc. (“Arris”) also
filed a petition for IPR of claims 1–20 of the ’404 patent. In
both the Cisco and Arris (collectively, “Appellants”) IPRs,
the USPTO’s Patent Trial and Appeal Board (“PTAB”) is-
sued final written decisions finding, inter alia, that the
claims were not unpatentable over a combination of the
prior art. See Arris Grp., Inc. v. TQ Delta, LLC, No.
IPR2016-01160, 2017 WL 6398317, at *7 (P.T.A.B. Dec. 13,
2017); ARRIS Grp., Inc. v. TQ Delta, LLC, No. IPR2016-
01160, 2018 WL 1176779, at *3 (P.T.A.B. Mar. 5, 2018)
(denying rehearing); see also Cisco Sys., Inc. v. TQ Delta,
LLC., IPR No. 2016-01466 (P.T.A.B. Feb. 7, 2018) (J.A. 1–
16).
    Appellants appeal. Because we have already deter-
mined that claims 6, 11, 16, and 20 of the ’404 patent would
have been obvious, see TQ Delta, slip op. at 19, the issue of
patentability of these claims is mooted in this appeal, see
ArcelorMittal v. AK Steel Corp., 856 F.3d 1365, 1370 (Fed.
Cir. 2017) (“A case becomes moot—and therefore no longer
a Case or Controversy for purposes of Article III—when the
issues presented are no longer live or the parties lack a le-
gally cognizable interest in the outcome.” (internal quota-
tion marks omitted) (citing Already, LLC v. Nike, Inc., 568
U.S. 85, 91 (2013))). The remaining claims being chal-
lenged on appeal are the patentability of claims 1–5, 7–10,
12–15, and 17–19 (“the Challenged Claims”). We have ju-
risdiction pursuant to 28 U.S.C. § 1295(a)(4)(A) (2012). We
vacate and remand.
                       BACKGROUND
    Entitled “Multicarrier Transmission System with Low
Power Sleep Mode and Rapid-On Capability,” the ’404 pa-
tent relates to the field of “multicarrier transmission sys-
tems.” ’404 patent col. 1 l. 31. Relevant here, the exact
4                         CISCO SYSTEMS, INC. v. TQ DELTA, LLC




term “synchronization signal” appears only in the claims.
See id. col. 10 l. 6–col. 12 l. 6. However, the specification
describes a “synchronizing pilot tone 62a,” id. col. 7 l. 15,
and refers to it as “a timing reference signal,” id. col. 5 ll.
38–39. The specification similarly describes using the
“timing reference signal” for “synchronization” as well as
other types of timing signals. See id. col. 5 ll. 39–45 (de-
scribing the “timing reference signal” being “synchronized
with the Master Clock in the transmitter” and explaining
that “[o]ther forms of timing signal[s] may, of course, be
used”).
   Independent claim 6 1 is illustrative and recites in rele-
vant part:
    An apparatus comprising a transceiver operable
    to . . . receive, in the full power mode, a synchroni-
    zation signal; . . . [and] receive, in the low power
    mode, a synchronization signal; and exit from the
    low power and restore the full power mode by using
    the at least one parameter and without needing to
    reinitialize the transceiver.



    1    While Cisco and Arris challenge certain claims in
the instant appeal that are not challenged in the related
appeal issued today, see TQ Delta, slip op. at 2, neither
party disputes the PTAB’s selection of independent claim 6
as illustrative of the Challenged Claims, nor do they pre-
sent any argument why claims 1–5, 7–10, 12–15, and 17–
19 are separately patentable, see generally Cisco’s Br.; Ar-
ris’s Br. Thus, we need not separately address those de-
pendent claims.       See Affinity Labs of Tex., LLC v.
DIRECTV, LLC, 838 F.3d 1253, 1264 n.4 (Fed. Cir. 2016)
(holding that when “[a party] has not separately argued the
patent eligibility of the dependent claims,” it “has waived
any argument that those claims should be analyzed sepa-
rately”).
CISCO SYSTEMS, INC. v. TQ DELTA, LLC                         5



Id. col. 10 ll. 29–43 (emphases added).
                         DISCUSSION
        I. Standard of Review and Legal Standard
    “We review the PTAB’s factual findings for substantial
evidence and its legal conclusions de novo.” Redline Detec-
tion, LLC v. Star Envirotech, Inc., 811 F.3d 435, 449 (Fed.
Cir. 2015) (citation omitted). “Substantial evidence is
something less than the weight of the evidence but more
than a mere scintilla of evidence,” meaning that “[i]t is such
relevant evidence as a reasonable mind might accept as ad-
equate to support a conclusion.” In re NuVasive, Inc., 842
F.3d 1376, 1379–80 (Fed. Cir. 2016) (internal quotation
marks and citations omitted). “If two inconsistent conclu-
sions may reasonably be drawn from the evidence in rec-
ord, the PTAB’s decision to favor one conclusion over the
other is the epitome of a decision that must be sustained
upon review for substantial evidence.” Elbit Sys. of Am.,
LLC v. Thales Visionix, Inc., 881 F.3d 1354, 1356 (Fed. Cir.
2018) (internal quotation marks, brackets, and citation
omitted).
    At the time of the Final Written Decisions, the PTAB
gave “[a] claim . . . its broadest reasonable construction in
light of the specification of the patent in which it appears.”
37 C.F.R. § 42.100(b) (2017). A specification “includes both
the written description and the claims” of the patent. In re
Packard, 751 F.3d 1307, 1320 n.11 (Fed. Cir. 2014). “A pa-
tent’s specification, together with its prosecution history,[2]
constitutes intrinsic evidence to which the PTAB gives pri-
ority when it construes claims.” Knowles Elecs. LLC v.


    2   A patent’s prosecution history “consists of the com-
plete record of the proceedings before the [US]PTO,” which
provides “evidence of how the [US]PTO and the inventor
understood the patent.” Phillips v. AWH Corp., 415 F.3d
1303, 1317 (Fed. Cir. 2005) (en banc) (citations omitted).
6                         CISCO SYSTEMS, INC. v. TQ DELTA, LLC




Cirrus Logic, Inc., 883 F.3d 1358, 1361−62 (Fed. Cir. 2018)
(citation omitted). We review the PTAB’s assessment of
the intrinsic evidence de novo. See id. at 1362.
II. The PTAB Improperly Construed the “Synchronization
                  Signal” Limitation
     The PTAB construed illustrative claim 6’s term “syn-
chronization signal” to mean “a signal allowing synchroni-
zation between the clock of the transmitter of the signal
and the clock of the receiver of the signal.” J.A. 10; Arris
Grp, 2017 WL 6398317, at *4. 3 The PTAB further clari-
fied, when rendering its obviousness determination, that
“[its] construction of ‘synchronization signal’ excludes a
synchronization frame.” Arris Grp., 2017 WL 6398317, at
*6. Appellants assert that by improperly limiting the con-
struction of “synchronization signal” to “a signal allowing
synchronization between the clock of the transmitter of the
signal and the clock of the receiver of the signal,” the PTAB
did not apply “the broadest reasonable [interpretation] in
light of the specification of the ’404 patent.” Cisco’s Br. 23;
Arris’s Br. 31. 4         Cisco specifically asserts that


    3    Arris and Cisco raised similar claim construction
challenges and the PTAB ultimately made identical or sub-
stantially similar determinations in both IPRs. See ARRIS
Grp., Inc. v. TQ Delta, LLC, No. IPR2016-01160, 2018 WL
1176779, at *3 (P.T.A.B. Mar. 5, 2018) (denying rehearing);
Cisco Sys., Inc. v. TQ Delta, LLC, IPR2016-01466 (P.T.A.B.
Feb. 7, 2018) (J.A. 1–16). Unless otherwise noted, we will
cite to the determination in ARRIS yet, our holdings apply
equally to ARRIS and Cisco.
     4   Appellants articulate substantially similar argu-
ments as to the “synchronization signal” limitation on ap-
peal. See Arris’s Br. 26; Cisco’s Br. 23. As such, we address
their arguments together. We use “Appellants” to refer to
arguments made by both parties and “Arris” or “Cisco” to
refer to arguments made by that party alone.
CISCO SYSTEMS, INC. v. TQ DELTA, LLC                        7



“synchronization signal” includes “a signal used to main-
tain timing between transceivers.” Cisco’s Br. 35. We
agree with Appellants.
     The ’404 patent’s claims and specification teach that
“synchronization signal” means “a signal allowing frame
synchronization between the transmitter of the signal and
the receiver of the signal,” and is not limited to describing
what the signal must synchronize or to a particular type of
synchronization. We begin our analysis with the claim lan-
guage. In re Power Integrations, Inc., 884 F.3d 1370, 1376
(Fed. Cir. 2018) (“[C]laim construction must begin with the
words of the claims themselves.” (citation omitted)). The
term “synchronization signal” is recited twice in claim 6:
first, the transceiver “receive[s], in the full power mode, a
synchronization signal,” ’404 patent col. 10 l. 33, and sec-
ond, the transceiver “receive[s], in the low power mode, a
synchronization signal,” id. col. 10 l. 39. We also look to
the surrounding claim language for context when the illus-
trative claim does not provide much clarification. See Phil-
lips, 415 F.3d at 1314 (“Other claims of the patent in
question, both asserted and unasserted, can also be valua-
ble sources of enlightenment as to the meaning of a claim
term.”). The “receiving a plurality of superframes” element
of the independent claim 1, however, only refers to the full
power mode. ’404 patent col. 10 ll. 2–4 (“An apparatus com-
prising a transceiver operable to: transmit, in full power
mode, a plurality of superframes. . . .”). Claim 6, therefore,
explains that the transceiver operates in in full power
mode at least when transmitting the “plurality of super-
frames.”
    The remainder of the specification does not expressly
define or even recite the term “synchronization signal.”
However it still provides useful insight for claim construc-
tion purposes. See generally ’404 patent; see Trs. of Colum-
bia Univ. v. Symantec Corp., 811 F.3d 1359, 1363 (Fed. Cir.
2016) (“[T]he specification is always highly relevant to the
claim construction analysis and is, in fact, the single best
8                         CISCO SYSTEMS, INC. v. TQ DELTA, LLC




guide to the meaning of a disputed term.” (internal quota-
tion marks and citation omitted)). 5 The ’404 patent’s writ-
ten description explains that in its preferred embodiment,
timing reference signal is the signal that allows “both” the
synchronization of the respective transmitter and receiver
clocks, as well as the synchronization of the transmitter
and receiver frame counters. ’404 patent col. 5 ll. 37–45.
The specification describes “[o]ther forms of timing signals”
that may be used, as well as one embodiment as “advanta-
geous[].” Id. col. 5 ll. 45, 42. As such, without any clear
indication otherwise in the specification, synchronization
is not restricted to the “advantageous” clock-based pre-
ferred embodiment as described in the specification. See
Liebel-Flarsheim Co v. Medrad, Inc., 358 F.3d 898, 913
(Fed. Cir. 2004) (explaining that “it is improper to read lim-
itations from a preferred embodiment described in the
specification—even if it is the only embodiment—into the
claims absent a clear indication in the intrinsic record that
the patentee intended the claims to be so limited”). Addi-
tionally, the ’404 patent’s “timing reference signal” pro-
vides the reference for both frequency and frame
synchronization, and the presence of frame synchroniza-
tion requires frequency synchronization. See ’404 patent
col. 5 ll. 37–41 (explaining that “[d]uring normal (non-sleep
mode) operation, a phase-lock loop (PLL) 62 receives . . . a


    5    The PTAB based its construction on the specifica-
tion’s reference to a “timing reference signal” in the “nor-
mal (non-sleep mode) operation,” as representative of the
claimed “synchronization signal.” Arris Grp., 2017 WL
6398317, at *3–5; see ’404 patent col. 5 l. 37; see also
J.A. 2350 (explaining, in Arris’s Petition for IPR, that
“[t]he timing reference signal is thus inferred to be repre-
sentative of th[e synchronization signal] claim limitation),
2548 (providing, in Patent Owner Response to Petition for
IPR, that “the claimed ‘synchronization signal’ relates to
timing synchronization”).
CISCO SYSTEMS, INC. v. TQ DELTA, LLC                        9



timing reference signal 62a (see FIG. 1A) via a line 62b
[which] . . . is transmitted from the transmitter with which
the receiver 16 communicates (e.g., the CO transmitter)”);
J.A. 2834, 2866 (explaining, in Arris’s expert declaration,
that “[t]he ’404 [p]atent teaches the transmission of a tim-
ing signal to maintain synchronization between ADSL
transceivers called the ‘timing reference frame, each frame
having a duration of one symbol period of approximately
two hundred and fifty microseconds’”). The specification
explains that the timing reference signal “is advanta-
geously a pure tone of fixed frequency and phase which is
synchronized with the Master Clock in the transmitter; its
frequency defines the frame rate of the transceivers.” ’404
patent col. 5 ll. 41–45. Contrary to the PTAB’s conclusion,
we determine that the broadest reasonable interpretation
of the disputed claim term “synchronization signal” is
simply “used to establish or maintain a timing relationship
between transceivers between the transmitter of the signal
and the receiver of the signal,” meaning synchronization
signal includes frame synchronization.
    TQ Delta’s primary counterargument is unpersuasive.
TQ Delta asserts that “Arris fails to show that the [PTAB]
erred in finding that ‘synchronization signal’ does not in-
clude a ‘synchronization frame.’” Appellee’s Br. 46. How-
ever, the timing reference signal described in the
specification allows for both frequency and frame synchro-
nization. ’404 patent col. 5 ll. 48–53 (explaining that “[t]he
PLL 62 locks itself to [the timing reference] signal and
drives clock 30 in synchronism with the Master Clock in
the driving transmitter” and that this mechanism “also
synchronizes frame counter 34 of the CPE transceiver to
the corresponding frame counter of the CO transceiver”).
As explained by the ’404 patent, the timing reference signal
“synchronizes frame counter 34 of the CPE transceiver to
the corresponding frame counter of the CO transceiver.”
Id. col. 5 ll. 50–52. Therefore, because the existence of the
frame synchronization requires frequency synchronization,
10                      CISCO SYSTEMS, INC. v. TQ DELTA, LLC




the “timing reference signal” demonstrates that the “syn-
chronization signal,” as disclosed by the Challenged
Claims, is necessary. See id. col. 5 ll. 41–45 (explaining
that the transmitter’s “frequency defines the frame rate of
the transceivers”). Thus, we vacate the PTAB’s claim con-
struction and we remand for the PTAB to consider Appel-
lants’ unpatentability challenge under the proper claim
construction.
                       CONCLUSION
    We have considered the parties’ remaining arguments
and find them unpersuasive. Accordingly, the Final Writ-
ten Decisions of the U.S. Patent Trial and Appeal Board
are vacated and the case is remanded.
             VACATED AND REMANDED
