Dali Wireless Inc. v. Commscope Technologies LLC, Commscope Holding Company, Inc.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
DALI WIRELESS INC.,
Plaintiff-Appellant
v.
COMMSCOPE TECHNOLOGIES LLC,
COMMSCOPE HOLDING COMPANY, INC.,
Defendants-Appellees
______________________
2022-1699
______________________
Appeal from the United States District Court for the
District of Delaware in No. 1:19-cv-00952-MN, Judge
Maryellen Noreika.
______________________
Decided: October 18, 2023
______________________
CRISTOFER L EFFLER, Folio Law Group PLLC, Seattle,
WA, argued for plaintiff-appellant. Also represented by
ALEXANDRA O. F ELLOWES , STEFAN SZPAJDA; J OSEPH
ABRAHAM , Austin, TX.
WILLIAM F. BULLARD, Carlson, Caspers, Vandenburgh
& Lindquist PA, Minneapolis, MN, argued for defendants-
appellees. Also represented by P HILIP P. CASPERS , SAMUEL
A. HAMER .
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 2
______________________
Before P ROST , HUGHES , and STOLL , Circuit Judges.
STOLL , Circuit Judge.
Dali Wireless Inc. appeals from a stipulated judgment
of noninfringement of U.S. Patent No. 8,682,338 following
an adverse claim construction ruling from the United
States District Court for the District of Delaware. For the
following reasons, we agree with the district court that the
“translating” limitation is not conditional and agree with
the district court’s constructions of the “packetizing” and
“routing and switching” limitations. We therefore affirm
the district court’s noninfringement judgment.
BACKGROUND
Dali owns the ’338 patent, which discloses methods of
routing and switching signals in a distributed antenna sys-
tem (DAS). ’338 patent col. 1 ll. 15–19, col. 5 ll. 52–56. A
DAS is a cellular communication system that distributes
radio signals from a network operator’s signal source to us-
ers’ mobile devices. See id. Fig. 3, col. 1 l. 15–col. 2 l. 26.
This system enhances signal coverage in areas with limited
access to cell towers and areas that lack the capacity to
support a high density of users, such as office buildings or
stadiums. See id. The basic DAS architecture includes a
central hub—for example, a digital access unit (DAU)—
connected via cables to a network of remote radio units
(RRUs) placed throughout the building or stadium. See
id. Fig. 3, col. 4 ll. 39–44, col. 5 ll. 62–64. The DAU pro-
vides a wired connection to the operator’s signal source,
and the RRUs provide a wireless connection to users’ mo-
bile devices. See id. Fig. 3.
In a DAS, RRUs are generally mounted in specific lo-
cations that expect a high density of users. Id. at col. 1
l. 47–col. 2 l. 10. However, this high concentration of users
may move to different locations throughout the day and
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 3
physically moving the RRUs as the concentration of users
moves is not practical. Id. at col. 1 l. 23–col. 2 l. 26. Ac-
cordingly, the ’338 patent discloses a “dynamic” method for
managing and allocating radio resources to particular
RRUs where they are most needed. Id. at col. 3 l. 51–col 4
l. 8, col. 8 ll. 21–24, col. 11 ll. 40–53.
The claimed system transports signals in two direc-
tions: downlink and uplink. Downlink signals are signals
traveling from the operator’s signal source to mobile users,
and uplink signals are signals traveling from mobile users
to the operator’s signal source. Id. at col. 5 l. 64–col. 6 l. 9.
The claimed system encounters at least two types of sig-
nals: baseband (also referred to as “base band”) and radio
frequency (RF) signals. Baseband signals are low fre-
quency signals, which are more suitable for wired trans-
mission—for example, between the DAU and RRU. See id.
at col. 5 l. 64–col. 6 l. 4. RF signals are higher frequency
signals, which are more suitable for wireless transmis-
sion—for example, between the RRUs and mobile phones.
See id. at col. 6 ll. 4–9. Depending on the type of transmis-
sion, signals can be translated between RF and baseband.
See id. at col. 5 l. 64–col. 6 l. 9.
Claim 1 is representative and recites:
1. A method for routing and switching RF signals
comprising:
providing one or more remote radio units, each re-
mote radio unit configured to transmit one or more
downlink RF signals and to receive one or more up-
link RF signals;
providing at least one digital access unit configured
to communicate with the one or more remote radio
units;
translating the uplink and downlink signals be-
tween RF and base band as appropriate;
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 4
packetizing the uplink and downlink base band sig-
nals, wherein the packetized signals correspond to
a plurality of carriers;
configuring each remote radio unit to receive or
transmit a respective subset of the plurality of car-
riers, each respective subset of the plurality of car-
riers including a number of carriers;
reconfiguring each remote radio unit by:
determining a load percentage for each remote
radio unit; and
increasing or decreasing the number of carriers
in the respective subset of the plurality of car-
riers based on the load percentage; and
routing and switching the packetized signals
among the one or more remote radio units via the at
least one digital access unit according to a result of
the reconfiguring.
Id. at col. 13 ll. 2–25 (emphases added to highlight dis-
puted limitations).
Dali sued CommScope Technologies LLC and
CommScope Holding Company, Inc. (collectively,
“CommScope”), alleging CommScope’s OneCell system in-
fringes, inter alia, claims 1–3 of the ’338 patent. After an
initial claim construction order, the parties filed cross mo-
tions for summary judgment. The district court invited the
parties to submit supplemental claim construction briefing
relevant to CommScope’s noninfringement arguments. Af-
ter a hearing, the district construed the “translating . . . as
appropriate”; “packetizing”; and “routing and switching”
limitations. Dali Wireless, Inc. v. CommScope Techs. LLC,
No. 19-952, 2022 WL 621547 (D. Del. Mar. 3, 2022) (Deci-
sion). Following this supplemental claim construction, the
parties stipulated to final judgment that, under the district
court’s claim constructions, the accused product does not
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 5
infringe the asserted claims. The district court entered
judgment accordingly. Dali appeals. We have jurisdiction
under 28 U.S.C. § 1295(a)(1).
D ISCUSSION
We review claim construction de novo, except for nec-
essary subsidiary factual findings based on extrinsic evi-
dence, which we review for clear error. Teva Pharms. USA,
Inc. v. Sandoz, Inc., 574 U.S. 318, 331–32 (2015). On ap-
peal, Dali challenges the district court’s constructions of
(1) “translating the uplink and downlink signals between
RF and base band as appropriate”; (2) “packetizing the up-
link and downlink base band signals”; and (3) “routing and
switching the packetized signals among the one or more re-
mote radio units via the at least one digital access unit.”
I
We address the first two limitations together. The dis-
trict court held that “translating the uplink and downlink
signals between RF and base band as appropriate” is not
conditional and requires translation. Decision, 2022 WL
621547, at *3–4. The court also held the subsequent limi-
tation of “packetizing the uplink and downlink base band
signals” refers to the “baseband signals produced by the
prior ‘translating’ step.” Id. We adopt these constructions.
Dali’s primary argument is that “translating . . . as ap-
propriate” does not require translation each time the
method is performed. According to Dali, the phrase “as ap-
propriate” at the end of the translating limitation means
that the translating step is only performed when neces-
sary. In other words, translation from RF to baseband at
the DAU is required only when the downlink signal arrives
in RF. Appellant’s Br. 30. “[I]f the downlink signal is al-
ready in baseband, there is no need to translate it.” Id.
We agree with the district court that the claimed trans-
lating step is not conditional. Like the district court, we
reject Dali’s interpretation of “as appropriate” as meaning
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 6
that translation need not occur. The claim does not recite
“translating . . . as needed.” Nor does the claim recite
“translating unless not needed.”
The specification further supports that “as appropri-
ate” does not make the translation conditional. The speci-
fication explains:
For the downlink (DL) path, RF signals received
from the BTS are separately down-converted, dig-
itized, and converted to baseband . . . . For the up-
link (UL) path optical signals received from RRUs
are de-serialized, deframed, and up-converted dig-
itally using a Digital Up-Converter. Data streams
are then independently converted to the analog do-
main and up-converted to the appropriate RF fre-
quency band.
’338 patent col. 5 l. 64–col. 6 l. 9 (emphases added). None
of this language is conditional or optional. Instead, the
specification teaches the uplink and downlink signals “are”
converted. Id.
The district court interpreted “as appropriate” to mean
“the amount of translation necessary to produce a base-
band signal from an RF signal.” Decision, 2022 WL
621547, at *1. We think it possible that, instead, “as ap-
propriate” modifies “between RF and base band” such that
the claimed translating step covers either translating from
RF to baseband or from baseband to RF. However, because
we need only construe claim terms as much as necessary to
resolve the parties’ dispute, Vivid Techs., Inc. v. Am. Sci. &
Eng’g, Inc., 200 F.3d 795, 803 (Fed. Cir. 1999), we need not
resolve this aspect of the district court’s construction. We
must only resolve whether the translating step is condi-
tional, as Dali’s infringement theory depends on such con-
struction. As discussed above, we agree with the district
court that it is not. Under either interpretation of “as ap-
propriate,” translation is required by the claimed method.
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 7
We also agree with the district court that “packetizing
the uplink and downlink base band signals” refers to the
baseband signals produced by the previous “translating”
step. The antecedent basis for “the uplink and downlink
base band signals” is the “base band” signals referred to in
the required “translating” step. See ’338 patent col. 13
ll. 9–13. That is, the downlink RF signals must be trans-
lated to baseband before the packetizing step.
Dali argues claim 1 does not require downlink signals
be translated from RF to baseband because the claim is not
limited to receiving downlink signals in RF. Appellant’s
Br. 32–35. In support, Dali points to claim 6, which de-
pends from claim 1. Claim 6 adds the limitation that “the
first digital access unit is configured to communicate with
a first base station, and the second digital access unit is
configured to communicate with a second base station.”
’338 patent col. 14 ll. 8–11. According to Dali, claim 6 lim-
its the source of the downlink signals to a base station and
requires the DAU to receive downlink signals in RF. Ap-
pellant’s Br. 33. Based on this, Dali argues that independ-
ent claim 1 is not limited to receiving downlink RF signals
at the DAU. Id.
We are unpersuaded by Dali’s claim differentiation ar-
gument. Claim 6 simply adds the limitation that two DAUs
are “configured to communicate” with two base stations.
This limitation does not require that the downlink signals
are in RF. More importantly, we do not think the district
court’s construction requires that downlink signals are al-
ways received in RF at the DAU. It simply requires that
downlink signals be translated from RF to baseband at
some point before the packetizing step. In other words, un-
der the district court’s construction, claim 1 does not cover
a purely baseband system where no translation from RF to
baseband is required. This construction is consistent with
the specification, which states an object of the “present in-
vention” is “to facilitate conversion and transport of several
discrete relatively narrow RF bandwidths.” ’338 patent
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 8
col. 4 ll. 20–22 (emphases added); see also id. at col. 7 ll. 5–
6 (“The present invention facilitates conversion and
transport of several discrete relatively narrow RF band-
widths.” (emphases added)).
In sum, we adopt the district court’s construction of the
“translating” limitation to the extent it held translation is
not conditional. We also adopt the district court’s construc-
tion of the “packetizing” limitation.
II
We next address the “routing and switching” limita-
tion. The district court held that “‘routing and switching
the packetized signals among the one or more remote radio
units via the at least one digital access unit’ refers to ‘the
packetized signals’ produced by the ‘packetizing’ step and
includes both uplink baseband signals and downlink base-
band signals that were previously packetized.” Decision,
2022 WL 621547, at *1, *5. Dali argues this construction
is erroneous because the plain language of the claim limits
this term to downlink signals. Appellant’s Br. 52–54.
We agree with the district court that this limitation in-
cludes both uplink and downlink signals. The claim lan-
guage recites “routing and switching the packetized
signals.” ’338 patent col. 13 l. 23 (emphasis added). The
antecedent basis for “the packetized signals” is the signals
produced in the previous packetizing step, which recites
both “uplink and downlink base band signals.” Id.
at col. 13 l. 11. Moreover, the specification depicts routing
and switching in both the uplink and downlink directions.
See id. Fig. 1 (downlink), Fig. 2 (uplink). In describing Fig-
ure 2, which depicts the claimed invention operating in the
uplink direction, the specification explains the uplink “sig-
nals resulting from processing performed within each of
the four RRU are routed to the two DAUs.” Id. at col. 9
ll. 27–31.
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DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC 9
Dali nevertheless argues the district court’s construc-
tion is “nonsensical” because the claim language “among
the one or more remote radio units via the at least one dig-
ital access unit” inherently means the signal is flowing in
the downlink direction—i.e., from the DAU towards the
RRUs. Appellant’s Br. 54–57. We disagree. Instead, this
claim language encompasses the embodiment in Figure 2,
which depicts uplink signals coming from “among” the
RRUs and flowing “through” the DAU. ’338 patent Fig. 2;
see also Decision, 2022 WL 621547, at *5 (construing “via”
as “through”). We therefore adopt the district court’s con-
struction of the “routing and switching” limitation.
CONCLUSION
We have considered the parties’ remaining arguments
and find them unpersuasive. For the reasons discussed
above, we agree with the district court that the “translat-
ing” limitation is not conditional. We also agree with the
district court’s constructions of the “packetizing” and “rout-
ing and switching” limitations. Accordingly, we affirm the
district court’s judgment of noninfringement.
AFFIRMED
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