Court Opinion

ID: 4150583
Source: CourtListenerOpinion
Date Created: 2017-03-07 16:06:36.778164+00
Date Added: 2024-06-11T07:46:30.716408
License: Public Domain

United States Court of Appeals
      for the Federal Circuit
                 ______________________

          COMCAST IP HOLDINGS I LLC,
               Plaintiff-Appellee

                            v.

  SPRINT COMMUNICATIONS COMPANY, L.P.,
 SPRINT SPECTRUM LP, NEXTEL OPERATIONS,
                    INC.,
             Defendants-Appellants
            ______________________

                       2015-1992
                 ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:12-cv-00205-RGA, Judge
Richard G. Andrews.
                ______________________

                 Decided: March 7, 2017
                 ______________________

    MATTHEW B. LEHR, Davis Polk & Wardwell LLP,
Menlo Park, CA, argued for plaintiff-appellee. Also repre-
sented by ANTHONY I. FENWICK, GARETH DEWALT, DAVID
LISSON.

    BRIAN CHARLES RIOPELLE, McGuire Woods LLP,
Richmond, VA, argued for defendants-appellants. Also
represented by DAVID EVAN FINKELSON, BRIAN DAVID
SCHMALZBACH; RACHELLE HARLEY THOMPSON, Raleigh,
NC.
2   COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.

    Before O’MALLEY, REYNA, and CHEN, Circuit Judges.
CHEN, Circuit Judge.
    Comcast IP Holdings I LLC (Comcast) sued Sprint
Communications Company LP, Sprint Spectrum L.P., and
Nextel Operations, Inc. (collectively, Sprint) for infringe-
ment of, among other patents, U.S. Patent Nos. 8,170,008,
7,012,916, and 8,204,046 (collectively, Low Patents),
which are generally directed to the use of computer net-
work technology to facilitate a telephone call (phone call
or call). After a jury trial, the jury found that Sprint’s
handling of certain phone calls infringed claims 1, 13, and
27 of the ’008 Patent, claim 45 of the ’916 Patent, and
claims 90 and 113 of the ’046 Patent, and awarded Com-
cast a $7.5 million damages award. The district court
then denied Sprint’s motion for judgment as a matter of
law (JMOL), or in the alternative, for a new trial, and
added prejudgment interest to the damages award.
Sprint has appealed various rulings from the district
court. Because we see no error in these rulings, we affirm
the district court’s entry of judgment against Sprint.
                       BACKGROUND
                 A. The Claimed Inventions
    The Low Patents are in the same patent family 1 and
are generally directed to methods of using Domain Name
System (DNS) technology, such as the Internet, to initiate
and route a phone call through a switched telecommuni-
cation system.
    One example of a switched telecommunication system
is a public switched telephone network (PSTN), which

    1   The Low Patents share the same specification so
we cite to the ʼ008 Patent for convenience.
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.    3

provides for a bearer channel (i.e., “interconnection”)
between two telephones “according to a called-party
telephone number input at the calling-party telephone.”
ʼ008 Patent col. 2 ll. 13–17; see also id. col. 1 ll. 31–41
(defining a switched telecommunication system as “a
system comprising a bearer network with switches for
setting up a bearer channel through the network”). A
PSTN is shown in Figure 1.

Id. fig. 1. In Figure 1
    customer premises equipment, CPE[] 10 (such as
    standard analogue telephones . . . . ) are connected
    through an access network 11 to switching points,
    SPs 12.     The SPs 12 form nodes in an inter-
    exchange network 13 made up of interconnecting
    trunks 14 and SPs that are controlled by control
    entities 15 in the SPs. The control effected by the
    control entities 15 is determined by signalling in-
    puts received from the CPEs and other SPs, and
    involves call setup, maintenance and clearance to
    provide the desired bearer channel between call-
    ing CPE and called CPE. Conceptually, the PSTN
    may be thought of as a bearer network and a con-
    trol (signalling) network, the function of the latter
    being to effect call control through the bearer
    network, namely the control of setup, mainte-
    nance and take down of bearer channels through
    the bearer network; in practice, the bearer and
    signalling networks may use the same physical
    circuits and even the same logical channels.
4   COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.

Id. col. 2 ll. 19–35.
     The Low Patents also explain that a “communication
system” generally has “a broader meaning than switched
telecommunication system” and “include[s] datagram-
based communication systems where each data packet is
independently routed through a bearer network without
following a predetermined bearer channel.” Id. col. 1 ll.
50–55. One example of a datagram-based communication
system is the Internet. See, e.g., Appellant Br. at 40.
   Asserted claim 1 is representative of the claimed in-
vention in the ’008 Patent:
    1. A method, comprising:
        receiving, over a switched telecommunica-
        tion system, a request;
        determining, responsive to the request, a
        call destination using domain name sys-
        tem signaling; and
        initiating a call through the switched tele-
        communication system between a calling
        party and the call destination that was de-
        termined as a result of said domain name
        system signaling.
Id. col. 32 ll. 46–55.
    Asserted claims 45 and claim 90 below are repre-
sentative of the claimed inventions for the ’916 Patent
and the ’046 Patent.
    45. A method of accessing communications data
    for contacting a target entity, said method com-
    prising:
        forming, from a number string identifying
        the target entity, a domain name by a pro-
        cess including parsing at least a substan-
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.   5

        tial portion of the number string into at
        least a part of said domain name;
        supplying the domain name formed to a
        DNS-type database system and receiving
        back a resource record including an URI
        [uniform resource identifier] for locating
        communications data associated with the
        domain name; and
        using the URI received back to access said
        communications data.
’916 Patent col. 36 ll. 56–67.
    90. A method, comprising:
        forming, by at least one computing device,
        from a number string identifying a target
        entity, a domain name by a process includ-
        ing parsing at least a portion of the num-
        ber string into at least a part of said
        domain name; and
        supplying, by the at least one computing
        device, the domain name to a database
        and receiving back from that database a
        resource record including a uniform re-
        source identifier (URI) of the target entity.
’046 Patent col. 45 l. 65–col. 46 l. 6.
                    B. The Accused Methods
    The six accused methods are ways in which Sprint
connects a calling party with a called party (call flows),
and there is no dispute as to how these accused call flows
operate.
    Comcast accused three call flows of infringing the ’008
Patent. See Appellant Br. at 15. These calls generally
begin on Sprint’s wireless cellular network that uses a
standard known as Code Division Multiple Access, or
6   COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.

“CDMA” (CDMA Network). The calls then travel through
an Internet Protocol Multimedia Subsystem network
(IMS Network). “The IMS Network includes an IMS core,
which is a collection of servers on a packet-based network
used to route and process signaling traffic” for the calls.
Id. at 16 n.7.
     When a call enters the IMS core, it does so through a
media gateway controller, or “MGC.” Id. at 18. Once the
call enters the IMS core, “a network element named a call
session control function (‘CSCF’) uses [DNS] signaling to
determine an IP address used to route the call to a session
border controller (‘SBC’).” Id. at 18–19. “The SBC is
another server on the IMS core.” Id. at 19. From there,
the call is routed outside of the IMS core, and then back
into the IMS core to another MGC. Id. “The MGC is not
specific to any particular telephone number or service
provider.” Id. From the MGC, the call is ultimately
routed to the called party. Id.
    Comcast accused another three call flows of infringing
the ’916 Patent and the ’046 Patent. Id. at 15. Common
to these call flows are their use of a process referred to as
“ENUM” to route calls through the IMS core. “That
method starts with a [called] telephone number, removes
any special characters, reverses the numbers, places a dot
between each number, and adds ‘e.164.arpa’ to the end” of
the number.” Id. at 27.
                  C. Procedural Background
    Comcast asserted claims 1, 13, and 27 of the ’008 Pa-
tent, claim 45 of the ’916 Patent, and claims 90 and 113 of
the ’046 Patent against Sprint in the District of Dela-
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.    7

ware. 2 The parties disputed the claim constructions for,
among other terms, the term “switched telecommunica-
tion system” in the ’008 Patent and the term “parsing” in
the ’916 Patent and the ’046 Patent. For the term
“switched telecommunication system,” the parties disa-
greed as to whether such a system could include elements
of a datagram-based system. J.A. at 3. The district court
concluded that “[a] system with elements of both switches
and a ‘datagram-based system’ is not necessarily outside
the scope of a ‘switched telecommunication system.’” Id.
at 4. “A ‘communication system’ is still a broader concept
than a ‘switched telecommunication system’ even where
the ‘switched telecommunication system’ has elements of
a ‘datagram-based system,’ because a ‘switched telecom-
munication system’ at a minimum must have switches
and function on a bearer network.” Id.
    As for the term “parsing,” the district court deter-
mined that “parsing” was an automated process because it
necessarily required a computer. See id. at 39. And the
parties agreed that the term must include “analyzing a
string according to a set of rules of a grammar.” Id. at 40.
But they differed on whether the relevant prosecution
histories of the ’916 Patent and the ’046 Patent demon-
strated disavowals of claim scope so as to limit the term
“parsing.” See id. The district court saw no clear disa-
vowals of claim scope in the prosecution histories. Id.
    After a six-day jury trial, the jury found that all of the
asserted claims of the Low Patents were infringed by
their respective accused call flows and awarded Comcast
a lump sum payment of $7.5 million in damages. Id. at
49. Sprint then moved for JMOL, as well as for a new

    2  Other patents from the Low family were also as-
serted against Sprint, but they are irrelevant to this
appeal as they were not part of the trial.
8   COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.

trial, on several bases. See id. at 48–69. For example,
Sprint argued that there was insufficient evidence to
support the jury’s verdict as to the ’008 Patent because
Comcast’s evidence, in the form of expert testimony from
Dr. Eric Burger, only demonstrated that “any destination
along the way in route of a call” could be a “call destina-
tion,” and wrongly suggested that there could be “multiple
destinations” along a call flow. Id. at 53–54. Sprint
insisted this understanding of “call destination” was
flawed because the claim term can only refer to “the
absolute final point in the call flow, or the receiving
phone,” otherwise the term would be superfluous. Id. at
52, 54.
    The district court disagreed with Sprint. The district
court noted that the jury was instructed to apply the
common meaning of “call destination” in rendering its
verdict as neither party asked for a construction of the
claim term. Id. at 53 & n.1. The district court explained
that the jury could have reasonably concluded—based on
Comcast’s expert—that “there are intermediate ‘call
destinations’” along the accused call flows. Id. at 54. It
further explained that the jury could have “reasonably
look[ed] at the claims and conclude[d] that the word ‘a’
before the first use of the term call destination implied
that there could be more than one destination . . . .” Id.
    Sprint likewise contended that there was insufficient
evidence to prove that Sprint’s accused call flows in-
fringed the asserted claims of the ’916 Patent and the ’046
Patent because Comcast did not demonstrate that the
“parsing” limitation was met. Id. at 57–58. The court
disagreed again, citing testimony from Dr. Burger. See id.
at 59–60.
    Moreover, Sprint took exception to the district court’s
decision to tack on prejudgment interest to the $7.5
million damages award. Id. at 65. Sprint maintained
that prejudgment interest should only be calculated from
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO.   9

the time of first infringement of each patent until judg-
ment, rather than from the time of the relevant hypothet-
ical negotiation—here 2006—until judgment. Id. More
specifically, Sprint insisted that prejudgment interest
should not be applied to the damages relevant to the
infringement of the ’008 Patent and the ’046 Patent
because those patents had not yet been issued in 2006
(the time when the ’916 Patent was issued)—they were
only issued in 2012. Id. at 65–66.
    The district court rejected Sprint’s argument, observ-
ing that “both sides’ experts opined that the reasonable
royalty should be a lump sum resulting from a single
hypothetical negotiation that took place in 2006” if Sprint
were found to infringe all three patents. Id. at 66 (citing
trial transcript). Based on that agreement, the district
court concluded that “[a] hypothetical negotiation in 2006
would include each of the asserted patents, even if they
issued later, and the resulting negotiation would include
the fact that two of the patents issued later.” Id. (citing
ResQNet.com, Inc. v. Lansa, Inc., 594 F.3d 860, 872 (Fed.
Cir. 2010)). Moreover, because of the agreed-upon meth-
odology of using a lump sum award for infringement of all
of the patents, the district court noted the practical prob-
lem of assessing prejudgment interest on a per patent
basis where the lump sum verdict did not apportion the
damages for each patent. See id.
   Sprint has filed a timely appeal. We have jurisdiction
pursuant to 28 U.S.C. § 1295(a)(1) (2012).
                  STANDARDS OF REVIEW
    The law of the regional circuit controls our standard
of review for the denial of a motion for JMOL. 3 E.g.,

   3   In moving for a new trial before the district court,
Sprint merely rehashed its arguments for why it deserved
10 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

MobileMedia Ideas LLC v. Apple Inc., 780 F.3d 1159, 1164
(Fed. Cir. 2015). In the Third Circuit, review of such a
denial is without deference. See, e.g., Rinehimer v. Cem-
colift, Inc., 292 F.3d 375, 383 (3d Cir. 2002). We “review
the record in the light most favorable to the prevailing
party ‘unless the record is critically deficient of that
minimum quantum of evidence from which a jury might
reasonably afford relief.’” Potence v. Hazleton Area Sch.
Dist., 357 F.3d 366, 370 (3d Cir. 2004) (quoting Rotondo v.
Keene Corp., 956 F.2d 436, 438 (3d Cir. 1992)).
    The proper construction of a patent’s claims is an is-
sue of Federal Circuit law, and we apply the framework
set forth in Teva Pharmaceuticals USA, Inc. v. Sandoz,
Inc., __ U.S. __, __, 135 S. Ct. 831, 840–42 (2015). E.g.,
Power Integrations, Inc. v. Fairchild Semiconductor Int’l,
Inc., 843 F.3d 1315, 1326 (Fed. Cir. 2016). Under that
framework, intrinsic evidence and the ultimate construc-
tion of claim terms are reviewed de novo, and underlying
factual determinations concerning extrinsic evidence are
reviewed for clear error. See id. “Where an infringement
verdict relies on incorrect construction of the disputed
claim terms, this court may grant JMOL or order a new
trial to correct the error, depending on the degree of
difference between the incorrect construction and the
correct construction.” Finisar Corp. v. DirecTV Grp., Inc.,
523 F.3d 1323, 1333 (Fed. Cir. 2008). “If no reasonable
jury could have found infringement under the proper
claim construction, this court may reverse a district
court’s denial of JMOL without remand.” Id. (citing

judgment as a matter of law. Because we assess those
arguments in the context of its JMOL motion, we need not
address them again in the context of its motion for a new
trial.
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 11

Harris Corp. v. Ericsson Inc., 417 F.3d 1241, 1255–57
(Fed. Cir. 2005)).
    Determination of infringement is a question of fact,
which, in the context of a jury trial, we review for sub-
stantial evidence. Union Carbide Chems. & Plastics Tech.
Corp. v. Shell Oil Co., 308 F.3d 1167, 1177 (Fed. Cir.
2002) (citing B. Braun Med., Inc. v. Abbott Labs., 124 F.3d
1419, 1423 (Fed. Cir. 1997)).
                        DISCUSSION
   A. Construction of “Switched Telecommunication Sys-
        tem” in the Asserted Claims of the ʼ008 Patent
    Sprint contends that the proper construction of
“switched telecommunication system” must be one that
excludes any element of a datagram-based system, so as
to render it consistent with the “fundamental require-
ment” of the ʼ008 Patent, which is that a phone call must
“travel[] over a predetermined bearer channel all the way
from the caller to the call destination.” Appellant Br. at
32–33 (emphasis added). Sprint’s insistence is not only
unpersuasive, but also irrelevant because the infringe-
ment verdict would remain unaffected even under its
narrower construction.
    We may affirm the jury’s findings on infringement if
substantial evidence appears in the record supporting the
jury’s verdict, and if correction of errors in claim construc-
tion would not have changed the verdict, given the evi-
dence presented. See Teleflex, Inc. v. Ficosa N. Am. Corp.,
299 F.3d 1313, 1328 (Fed. Cir. 2002) (citing Weinar v.
Rollform Inc., 744 F.2d 797, 808 (Fed. Cir. 1984)). Preju-
dicial error here requires “sufficient evidence . . . to sup-
port a finding of non-infringement under a correct
instruction.” CytoLogix Corp. v. Ventana Med. Sys., Inc.,
424 F.3d 1168, 1174 (Fed. Cir. 2005) (alteration omitted)
(quoting Ecolab, Inc. v. Paraclipse, Inc., 285 F.3d 1362,
1374 (Fed. Cir. 2002)).
12 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

     Here, even if “switched telecommunication system”
were construed so as to exclude any element of a data-
gram-based system, Sprint has not demonstrated how the
relevant accused call flows do not infringe the ’008 Patent.
In other words, Sprint has not shown prejudice. Sprint
does not dispute that its CDMA Network is where a call is
initiated or set up and that the CDMA Network is a
switched telecommunication system having no datagram-
based elements. See Appellant Br. at 39–40.
     Moreover, adoption of Sprint’s construction would not
permit it to argue that the ’008 Patent requires a call to
travel “exclusively” over a switched telecommunication
system. See id. at 16 (“None of the accused call flows
travels exclusively over a switched network or predeter-
mined bearer channels. Instead, each starts on Sprint’s
CDMA network, travels through Sprint’s . . . IMS . . .
network (a packet-based network), and eventually returns
to the CDMA network or the CDMA air interface for
routing to the called handset.” (footnotes omitted)). The
claim language does not demand this. Claims 1 and 13
only require “initiating a call through the switched tele-
communication system,” ’008 Patent col. 32 ll. 46–55; id.
col. 33 ll. 31–40 (emphasis added), and claim 27 only
requires “setting up a call through the switched telecom-
munication system,” id. col. 34 ll. 39–47 (emphasis add-
ed). These claims do not state that after a call is either
initiated or set up through a switched telecommunication
system, the call must also travel exclusively on that
system to a particular destination.
    The specification also does not support the construc-
tion that Sprint desires. It reveals that the ’008 Patent is
not directed to methods of transmitting an entire call
from a calling party’s phone to the called party’s phone;
rather, it is directed to methods, consistent with the claim
language, for initiating or setting up a call intended for
transmission to a called party. See id. col. 1 ll. 27–30
(“The present invention relates to a method of accessing
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 13

service resource items that are intended to be used in
setting up bearer channels through a switched telecom-
munications system.” (emphasis added)). And figure 15 in
the specification expressly contemplates a call that does
not travel exclusively on a switched telecommunication
system. See id. fig. 15; see also id. col. 27 ll. 10–14.
     To support its theory that the ’008 Patent requires a
call to travel exclusively on a switched telecommunication
system, Sprint relies on the specification’s explanation
that datagram-based elements are “logically distinct”
from the switched telecommunication system. See Appel-
lant Br. at 35–36 (citing ’008 Patent col. 11 l. 65–col. 12 l.
2). The specification explains that “[t]he intention of
requiring the computer network to be logically distinct
from the [switched] telecommunication[] system is to
exclude computer networks that are dedicated to the
management or monitoring of the bearer network and
effectively form part of the [switched] telecommunica-
tion[] system itself.” ’008 Patent col. 11 ll. 50–55. This
explanation, however, does not suggest that a call either
initiated or set up on a switched telecommunication
system cannot traverse any datagram-based elements
once it leaves the system.
    Accordingly, we sustain the jury’s verdict of infringe-
ment of claims 1, 13, and 27 of the ’008 Patent because
there is substantial evidence that the relevant accused
call flows were either initiated or set up on a switched
telecommunication system.
   B. Sufficiency of Evidence for “Call Destination” Limi-
       tation in Asserted Claims 1 and 13 and “Identifier
      of a Second Party” Limitation in Asserted Claim 27
                        of the ’008 Patent
    Sprint next complains that there was insufficient evi-
dence for the jury to find that the “call destination” limi-
tation of claims 1 and 13 of the ’008 Patent—which the
jury was instructed to apply its plain and ordinary mean-
14 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

ing because neither party asked for a construction—was
met by the relevant accused call flows. See Appellant Br.
at 41–50. According to Sprint, Comcast only presented
evidence that a call destination was any point on a call
flow, but a call destination must be the “final point on the
path of a call.” Id. at 43. We disagree with Sprint as
there is substantial evidence to support the jury’s finding
that the relevant accused call flows met the “call destina-
tion” limitation.
    Sprint “is essentially [proffering] a claim construction
argument regarding the meaning of the term [‘call desti-
nation’] . . . in the guise of a challenge to the sufficiency of
the evidence of infringement.” ePlus, Inc. v. Lawson
Software, Inc., 700 F.3d 509, 520 (Fed. Cir. 2012). Sprint
invites the court to construe the meaning of a call destina-
tion as the final point on the path of a call. But if Sprint
“desired such a narrow definition, it could (and should)
have sought a construction to that effect.” ePlus, 700 F.3d
at 520; see also Hewlett-Packard Co. v. Mustek Sys., Inc.,
340 F.3d 1314, 1321 (Fed. Cir. 2003) (“[W]here the parties
and the district court elect to provide the jury only with
the claim language itself, and do not provide an interpre-
tation of the language in the light of the specification and
the prosecution history, it is too late at the JMOL stage to
argue for or adopt a new and more detailed interpretation
of the claim language and test the jury verdict by that
new and more detailed interpretation. The verdict must
be tested by the charge actually given and by giving the
ordinary meaning of the language of the jury instruc-
tion.”). “In the absence of such a construction, however,
the jury was free to rely on the plain and ordinary mean-
ing of the term . . . .” ePlus, 700 F.3d at 520. And Sprint
“has not met its burden of showing that it has the only
reasonable view of the claim [limitation] . . . .” Avid Tech.,
Inc. v. Harmonic, Inc., 812 F.3d 1040, 1048 (Fed. Cir.
2016). As the district court correctly explained, the jury
could have “reasonably look[ed] at the claims and con-
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 15

clude[d] that the word ‘a’ before the first use of the term
call destination implied that there could be more than one
destination” rather than exclusively referring to the call’s
final destination. J.A. at 54.
    In light of this, the jury reasonably relied on
Dr. Burger’s testimony that the relevant accused call
flows were routed to at least one call destination.
Dr. Burger testified that the various servers inside the
IMS core, such as the MGC and the SBC, were call desti-
nations because the CSCF routed calls to those servers.
Id. at 4439, 4541–42. This testimony from Dr. Burger did
not, as Sprint suggests, invite the jury to find that any
point along the accused call flows was a “call destination.”
These were specific servers in the IMS core.
    Sprint’s complaints regarding the “identifier of a sec-
ond party” limitation in claim 27 of the ’008 Patent 4 are
similar to those that it lodges against the “call destina-
tion” limitation in claims 1 and 13. See Appellant Br. at
45. But for the reasons we reject that a “call destination”
must be the final point on a path of a call, we also reject

   4   Claim 27 reads:
   A method, comprising:
       receiving a request from a first party;
       determining by a computer, responsive to
       the request, an identifier of a second party
       using domain name system signaling;
       setting up a call through the switched tel-
       ecommunication system between the first
       party and the second party that was de-
       termined as a result of said domain name
       system signaling.
16 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

that an “identifier of a second party” must be a “unique
identifier of a second party.” First, if Sprint wanted this
restrictive construction of the term, it should have sought
one. But it never did and now is too late. See ePlus, 700
F.3d at 520; see also Hewlett-Packard, 340 F.3d at 1321.
Second, the jury reasonably relied on Dr. Burger’s testi-
mony that the term means “how you get to [a] second
party” and that DNS signaling in the IMS core deter-
mined an identifier of a second party, which could include
the SBC inside the IMS core. See J.A. at 4539–41.
    Because substantial evidence demonstrates that the
“call destination” limitation in claims 1 and 13 and the
“identifier of a second party” limitation in claim 27 were
met, we sustain the jury’s verdict that Sprint infringed
these claims of the ’008 Patent.
   C. Construction of “Parsing” in Asserted Claims of the
               ’916 Patent and the ’046 Patent
    Sprint also attacks the district court’s claim construc-
tion of the term “parsing” in the asserted claims of the
’916 Patent and the ’046 Patent. See Appellant Br. at 50–
57. Specifically, Sprint faults the district court for refus-
ing to find disclaimers in the prosecution histories and
imposing limitations on the scope of “parsing.” Id. at 50.
But Sprint fails to identify any prejudice associated with
the district court’s claim construction as it never explains
in its opening brief how its purportedly correct and nar-
rower claim construction would have affected the in-
fringement verdict. See CytoLogix, 424 F.3d at 1174.
    Sprint notes that page fifty of its opening brief ex-
plained how it was prejudiced. Reply Br. at 21 n.7 (citing
Appellant Br. at 50). We disagree. For example, Sprint
does not explain how the relevant accused call flows do
not practice the asserted claims under its narrower claim
construction. Sprint has thus waived any arguments
concerning how it was prejudiced by a broader construc-
tion of “parsing.” See SmithKline Beecham Corp. v.
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 17

Apotex Corp., 439 F.3d 1312, 1319 (Fed. Cir. 2006) (“Our
law is well established that arguments not raised in the
opening brief are waived.” (citation omitted)); see also
Fresenius USA, Inc. v. Baxter Int’l, Inc., 582 F.3d 1288,
1304 (Fed. Cir. 2009) (“[The appellant] failed to clearly
explain what result would occur if this court adopted [the
appellant’s] proposed claim constructions. [The appel-
lant] gave this court little guidance and cited no record
support regarding why a modified claim construction
would affect the infringement judgment, the validity
judgment, or both. For that reason alone, we may decline
to consider [the appellant’s] claim construction argu-
ments.”). Consequently, we sustain the jury’s verdict that
Sprint infringed the asserted claims of the ’916 Patent
and the ’046 Patent.
    Even without the waiver, we agree with the district
court’s construction of “parsing,” and its rejection of
Sprint’s prosecution disclaimer arguments concerning this
term. “[F]or prosecution disclaimer to attach, our prece-
dent requires that the alleged disavowing actions or
statements made during prosecution be both clear and
unmistakable.” Omega Eng’g, Inc. v. Raytek Corp., 334
F.3d 1314, 1325–26 (Fed. Cir. 2003). Where the prosecu-
tion history is ambiguous or susceptible to “multiple
reasonable interpretations” as to any alleged disavowal,
we decline to find prosecution disclaimer. Cordis Corp. v.
Medtronic AVE, Inc., 339 F.3d 1352, 1359 (Fed. Cir.
2003); Omega Eng’g, 334 F.3d at 1325.
    The district court construed “parsing” as “[a]n auto-
mated process of analyzing a string according to a set of
rules of a grammar.” J.A. at 40. But Sprint seeks a
narrower construction, contending that during the reex-
aminations of the ’916 Patent and the ’046 Patent, “Com-
cast distinguished ‘parsing’ from ‘predetermined
association’ and other processes such as ‘mapping,’
‘lookup,’ and ‘translating’” to avoid having the asserted
claims rejected. Appellant Br. at 52. While Comcast did
18 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

make statements indicating that such processes are not
the same as “parsing,” when read in context, we do not
read those statements as necessarily excluding any form
of these processes from “parsing.” See, e.g., Lucent Techs.,
Inc. v. Gateway, Inc., 525 F.3d 1200, 1211–12 (Fed. Cir.
2008) (“[T]he arguments made by the applicants during
prosecution clearly distinguish the claimed method from
that of [the prior art], but do not constrain the definition
of [the disputed claim term] as urged by the defendants.”).
Accordingly, we see no reason to disturb the district
court’s claim construction or the jury verdict.
                   D. Prejudgment Interest
    After an infringement finding, “the court shall
award . . . damages adequate to compensate for the in-
fringement . . . together with interest and costs . . . .” 35
U.S.C. § 284 (2012). “[P]rejudgment interest should be
awarded under § 284 absent some justification for with-
holding such an award.” Gen. Motors Corp. v. Devex Corp.,
461 U.S. 648, 657 (1983); see also Energy Transp. Grp.,
Inc. v. William Demant Holding A/S, 697 F.3d 1342, 1358
(Fed. Cir. 2012). We review the district court’s award of
prejudgment interest for an abuse of discretion. Gen.
Motors Corp., 461 U.S. at 657; see also Energy Transp.
Grp., 697 F.3d at 1358.
    Sprint contends that the district court erroneously
charged Comcast prejudgment interest from 2006 forward
even though neither the ’008 Patent nor the ’046 Patent
had issued at that point. Appellant Br. at 57–64. Specifi-
cally, because neither of those two patents had issued yet,
there could be no infringement as a matter of law for
them in 2006. In Sprint’s view, accordingly, the district
court’s award of prejudgment interest was an abuse of
discretion because the court should have calculated pre-
judgment interest from the time of first infringement of
each of the three infringed patents until judgment. In
other words, Sprint contends the district court should
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 19

have apportioned the prejudgment interest calculations
based on the royalty periods covered by the individual
patents. See id. While in other contexts Sprint’s conten-
tions might be well taken, they are not here.
   The parties’ experts agreed that any damage award
should take the form of a lump sum royalty payment.
And, the jury was told that the lump sum royalty pay-
ment should run from the date of the earliest relevant
hypothetical negotiation. Specifically, Comcast’s damages
expert, Ms. Carla Mulhern, explained to the jury how it
was to calculate damages as follows:
   Q. So when would this hypothetical negotiation
   have taken place had it actually taken place?
   A. The hypothetical negotiation is set at the time
   of first infringement. So, in this case, it’s a little
   complicated because we have multiple patents.
   So if the ’916 [P]atent is found to be infringed by
   Sprint, the hypothetical negotiation would have
   occurred at the time of first infringement of the
   ’916 [P]atent, which is in late 2006. . . .
   If Sprint is not found to have infringed the ’916
   [P]atent, but only either the ’046 or ’008 patents,
   which issued much later, then the hypothetical
   negotiation would occur in 2012 at the time of
   first infringement of those patents.
J.A. at 4593–94. Sprint’s damages expert Dr. Debra Aron
agreed with Ms. Mulhern’s statements on the timing of
the hypothetical negotiation:
   Q. You agree with Ms. Mulhern that if the ’916
   [P]atent or any combination of patents that in-
   cludes the ’916 [Patent] is found to be infringed,
   then the appropriate date for the hypothetical ne-
   gotiation for all infringed patents in this case is
   late 2006; correct?
20 COMCAST IP HOLDINGS I LLC v. SPRINT COMMUNICATIONS CO.

   A. Yes, that’s right.
   Q. And the analysis that both you and Ms. Mul-
   hern have done, you understand is directed to a
   lump sum royalty through the time of trial; cor-
   rect?
   A. That’s what it should be, yes.
   Q. And you and she agree on that point; correct?
   A. I think we agree on that point.
Id. at 4974–75. The jury was also told that the hypothet-
ical negotiators would have employed the “book of wis-
dom,” looking forward in time from the date of the first
hypothetical negotiation to account for “all information
that would have been relevant to the parties in coming to
and arriving at a deal.” Id. at 66; id. at 4594–95. Both
experts agreed that this information would have included
the issuance of any later patent relating to the same
technology. Id. at 4593–95; id. at 5002–03.
    As the verdict form reflects, the jury found that claims
in all three of the Low patents were infringed. Id. at 46–
47. And as it was invited to do, the jury then awarded
Comcast a lump sum royalty in the amount of $7.5 mil-
lion. Id. at 47. That award necessarily was predicated on
a hypothetical negotiation occurring in 2006. Because the
jury found the ’916 Patent infringed and the hypothetical
negotiation to have occurred in 2006 there was only one
damage award for the district court to consider when
assessing the dollar figure against which prejudgment
interest should be measured and the date from which it
was to run. There was, accordingly, neither a basis for
the district court to apportion prejudgment interest nor a
COMCAST IP HOLDINGS I LLC   v. SPRINT COMMUNICATIONS CO. 21

need for the district court to undertake such apportion-
ment. 5
    Prejudgment interest runs from the earliest date of
infringement for any patent issued at the time of the
hypothetical negotiation; here, the ’916 Patent indisputa-
bly had been issued by 2006. We see no abuse of discre-
tion in the district court’s assessment of prejudgment
interest against Sprint based on the entire royalty award.
See Bio-Rad Labs., Inc. v. Nicolet Instrument Corp., 807
F.2d 964, 969 (Fed. Cir. 1986) (“[T]he purpose of prejudg-
ment interest . . . is ‘to ensure that the patent owner is
placed in as good a position as he would have been had
the infringer entered into a reasonable royalty agree-
ment.’” (quoting Gen. Motors Corp., 461 U.S. at 655)); cf.
Stickle v. Heublein, Inc., 716 F.2d 1550, 1561 n.8 (Fed.
Cir. 1983) (“Since the parties treated the mechanical and
process patents as a unitary licensing property, we need
not consider damages for infringement of each patent
individually. Under other circumstances it may well be
necessary to determine damages separately for each such
patent since a patent owner has every right to demand
royalties for each patent he holds.”).
                       CONCLUSION
    For the preceding reasons, we AFFIRM the judgment
entered by the district court.

   5     The district court properly rejected Sprint’s sug-
gestion that it could have determined what portion of the
jury’s award was attributable to each patent, based on the
damages methodology employed by Ms. Mulhern. See
J.A. at 66. The jury’s award was less than half of what
Ms. Mulhern proposed, thereby indicating that the jury
did not actually follow her proposal. See Appellee Br. at
60 (citing J.A. at 47, 4635).