Court Opinion

ID: 9891385
Source: CourtListenerOpinion
Date Created: 2023-10-18 15:01:43.259994+00
Date Added: 2024-06-11T13:47:06.067506
License: Public Domain

Case: 22-1699   Document: 46     Page: 1    Filed: 10/18/2023

        NOTE: This disposition is nonprecedential.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 LEFFLER, Folio Law Group PLLC, Seattle,
 WA, argued for plaintiff-appellant. Also represented by
 ALEXANDRA O. FELLOWES, STEFAN SZPAJDA; JOSEPH
 ABRAHAM, Austin, TX.

     WILLIAM F. BULLARD, Carlson, Caspers, Vandenburgh
 & Lindquist PA, Minneapolis, MN, argued for defendants-
 appellees. Also represented by PHILIP P. CASPERS, SAMUEL
 A. HAMER.
Case: 22-1699     Document: 46      Page: 2    Filed: 10/18/2023

 2        DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC

                   ______________________

     Before PROST, 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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 4        DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC

     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).
                         DISCUSSION
      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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 6        DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC

 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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 8        DALI WIRELESS INC. v. COMMSCOPE TECHNOLOGIES LLC

 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