Ipcom Gmbh & Co. v. Htc Corporation , 861 F.3d 1362 ( 2017 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    IPCOM GMBH & CO.,
    Appellant
    v.
    HTC CORPORATION,
    Appellee
    ______________________
    2016-1474
    ______________________
    Appeal from the United States Patent and Trademark
    Office, Patent Trial and Appeal Board in No. 95/001,192.
    ______________________
    Decided: July 7, 2017
    ______________________
    MITCHELL G. STOCKWELL, Kilpatrick Townsend &
    Stockton LLP, Atlanta, GA, argued for appellant. Also
    represented by MICHAEL S. PAVENTO, DAVID A. REED.
    MICHAEL A. OBLON, Perkins Coie, LLP, Washington,
    DC, argued for appellee. Also represented by TYLER R.
    BOWEN, JONATHAN M. JAMES, Phoenix, AZ; DAN L.
    BAGATELL, Hanover, NH.
    ______________________
    Before PROST, Chief Judge, CLEVENGER and CHEN, Circuit
    Judges.
    2                      IPCOM GMBH & CO.   v. HTC CORPORATION
    CHEN, Circuit Judge.
    IPCom GmbH & Co. (IPCom) is the owner of U.S. Pa-
    tent No. 6,879,830 (’830 patent), which describes and
    claims a method and system for handing over a mobile
    phone call from one base station to another base station.
    After IPCom sued HTC Corporation (HTC) for infringing
    the ’830 patent, HTC requested that the U.S. Patent and
    Trademark Office (PTO) conduct inter partes reexamina-
    tion of claims 1, 5–26, and 28–37 of the ’830 patent, which
    the PTO granted. The reexamination went through two
    rounds of review by the Examiner and the Patent Trial
    and Appeal Board (Board). In the first round, the Exam-
    iner concluded that the claims were patentable, but HTC
    appealed to the Board, which issued a new ground of
    rejection for claims 1 and 5–30. In the second round,
    IPCom amended claims 1, 5–26, and 28–37, 1 but the
    Board found that these amended claims were obvious
    under 35 U.S.C. § 103 in view of various combinations of
    McDonald, 2 Anderson, 3 GSM, 4 and PACS. 5
    In its appeal, IPCom alleges that, even though it had
    amended the scope of claims 31–37 during its second
    round before the Examiner, the Board lacked jurisdiction
    to review the Examiner’s patentability determination of
    these amended claims in the Board decision now on
    1   IPCom cancelled claim 27. J.A. 3.
    2   U.S. Patent No. 5,222,248.
    3  U.S. Patent No. 6,088,590.
    4  Digital cellular telecommunications system
    (Phase 2+); Mobile radio interface layer 3 specification
    (GSM 04.08 version 6.1.1 Release 1997). J.A. 13225; see
    infra Background Part III.
    5  American National Standard for Telecommunica-
    tions-Personal Access Communications System Air Inter-
    face Standard (approved November 16, 1998). J.A. 13823;
    see infra Background Part IV.
    IPCOM GMBH & CO.   v. HTC CORPORATION                      3
    appeal. IPCom also argues that the Board’s obviousness
    rejections were based on a flawed claim construction,
    because the Board never identified the structure in the
    patent specification that corresponds to the “arrangement
    for reactivating the link” means-plus-function claim
    limitation. IPCom also appeals the Board’s factual find-
    ings for several other claim limitations and the motiva-
    tion to combine the prior art references in the manner
    claimed by the ’830 patent.
    We conclude that, under the circumstances of this
    case, the Board properly had the authority to consider the
    patentability of claims 31–37 and thus reject IPCom’s
    procedural challenge to the Board’s rejection of these
    claims. But we agree with IPCom that the Board failed to
    conduct a proper claim construction of the “arrangement
    for reactivating the link” claim limitation, and we vacate
    and remand the obviousness rejections based on that
    limitation. We affirm the Board’s findings in all other
    respects.
    BACKGROUND
    The ’830 patent describes a method for performing
    handover (or handoff) of a cellular telephone or mobile
    station (MS) in a cellular telephone network from a first
    base station (BS1) to a second base station (BS2). ’830
    patent col. 1 ll. 14–62. Mobile stations communicate with
    a network by exchanging signals with a base station,
    where the base station is part of a wired network of base
    stations, fixed lines, and switching units. 
    Id. col. 2
    l. 64–
    col. 3 l. 3. Handover occurs in a network when the mobile
    station switches from one base station to another. 
    Id. col. 1
    ll. 25–28.
    The ’830 patent describes forward and forced hando-
    ver techniques. 
    Id. col. 5
    ll. 10–15, 61–64. A forward
    handover is one in which the mobile station, rather than
    the first base station, determines a handover is necessary,
    and seeks out the second base station. 
    Id. col. 1
    ll. 37–38.
    4                      IPCOM GMBH & CO.   v. HTC CORPORATION
    A forced handover is one in which the first base station
    initiates the handover, e.g., by sending a message to the
    mobile station instructing the mobile station to perform a
    handover to a second base station. 
    Id. col. 1
    ll. 53–56, col.
    2 ll. 24–31.
    To reduce the chance of interrupted service when a
    mobile station must perform a handover, the claimed
    invention calls for the first base station to maintain, for a
    period of time, the link data for the mobile station as well
    as hold in reserve link resources required to maintain a
    link between the mobile station and the first base station.
    When a handover of the mobile station to a second base
    station is unsuccessful, the mobile station reactivates the
    link with the first base station, e.g., by continuing to
    maintain the link. 
    Id. col. 2
    ll. 38–40, col. 5 ll. 10–15, 61–
    64, col. 6 ll. 13–53. By providing this feature, if the mo-
    bile station cannot establish a link with a second base
    station, the mobile station’s link with the first base sta-
    tion can be maintained without the mobile base station
    having to resend link information to the first base station.
    
    Id. col. 5
    ll. 24–26, col. 6 ll. 40–52. This feature is claimed
    in the “arrangement for reactivating the link” limitation
    in independent claims 1, 18, 30, and 34. J.A. 12565–74.
    Claim 1 is reproduced below:
    1. (Unamended) A mobile station for use with a
    network including a first base station and a sec-
    ond base station that achieves a handover from
    the first base station to the second base station by:
    storing link data for a link in a first base
    station,
    holding in reserve for the link resources of
    the first base station, and
    when the link is to be handed over to the
    second base station:
    IPCOM GMBH & CO.   v. HTC CORPORATION                     5
    initially maintaining a storage of the link
    data in the first base station,
    initially causing the resources of the first
    base station to remain held in reserve, and
    at a later timepoint determined by a fixed
    period of time predefined at a beginning of
    the handover, deleting the link data from
    the first base station and freeing up the
    resources of the first base station, the mo-
    bile station comprising:
    an arrangement for reactivating the link
    with the first base station if the handover
    is unsuccessful.
    J.A. 12565 (emphasis added). Independent claims 18, 30,
    and 34 also recite three additional limitations of (1) a
    “forced handover request message” from the first base
    station to the mobile station; (2) a “handover query” from
    the mobile station to a second base station; and (3) a
    “rejection message” from the second base station if the
    second base station cannot support the mobile station.
    Appellant Br. 10–11; J.A. 12570–74.
    The ’830 patent also describes a flexible type of hand-
    over, in which a handover is handled in different ways,
    depending on whether a network can support handover by
    transferring “link data” directly between the first and
    second base stations, or whether that information must be
    communicated directly from the mobile station to the
    second base station. ’830 patent col. 2 ll. 32–38, col. 3
    ll. 10–16. This feature is the “informing the mobile sta-
    tion” limitation recited in independent claims 5, 12, and
    16. J.A. 12566–70. Claim 5, for example, recites “inform-
    ing the mobile station whether the network is capable of
    transferring the link data from the first base station to
    the second base station.” J.A. 12567. The last relevant
    limitation in the challenged claims covers a network using
    6                     IPCOM GMBH & CO.   v. HTC CORPORATION
    different generations of radio communication standards
    and is recited in claims 23 and 25. J.A. 12571–72. These
    claims recite that “the first base station and the second
    base station operate in respective parts of the network
    using different generations of radiocommunications
    standards for radio communication with the mobile sta-
    tion.” J.A. 12571–72.
    For purposes of this appeal, the challenged claims can
    be separated into five categories. First, independent
    claims 1, 18, 30, and 34 recite the “arrangement for
    reactivating the link” means-plus-function limitation.
    Second, independent claims 18, 30, and 34 recite the
    “forced handover request message,” “handover query,”
    and “rejection message” limitations. Third, independent
    claims 5, 12, and 16 recite the “informing the mobile
    station” limitation. Fourth, dependent claims 23 and 25
    recite using different generations of radio communications
    standards. Fifth, claims 31–37 are challenged based on
    jurisdiction.
    I. McDonald
    As noted, the Board considered four prior art refer-
    ences. McDonald describes a technique for dealing with
    failed handovers. When a mobile station moves from one
    cell to a neighboring cell in a cellular telephone network,
    the mobile station searches for a second base station in
    the neighboring cell and sends an inbound signaling word
    (ISW) message to inquire whether a handover is possible.
    McDonald col. 1 ll. 30–33, col. 2 l. 66–col. 3 l. 9. If the
    second base station cannot support a handover, the net-
    work sends the mobile station a busy outbound signaling
    word (OSW) rejection message. 
    Id. col. 1
    ll. 42–46, col. 2
    ll. 1–3). The “busy OSW” signal informs the mobile
    station that the network cannot transfer link data from
    the first base station to the second base station. J.A. 7.
    The mobile station “can then choose to return” to the first
    base station by “deregister[ing]” from the second base
    IPCOM GMBH & CO.   v. HTC CORPORATION                      7
    station, “inform[ing]” the network that it is “returning to
    the previous channel,” and “attempt[ing] to receive” at the
    first base station. McDonald col. 3 ll. 14–21.
    II. Anderson
    Anderson describes “mobile directed” or “mobile cen-
    tric” handover techniques. Anderson col. 17 ll. 45–52.
    Anderson describes integrating multiple cellular network
    technologies, including GSM (prior art reference described
    infra at Background Part III) into a single network. 
    Id. col. 4
    ll. 40–61. It also describes several types of success-
    ful handovers, including a “make before break” handover.
    
    Id. col. 1
    5 l. 25–col. 18 l. 25. In this handover, the mobile
    station initiates a handover attempt based on a drop in
    link quality below a predetermined threshold level be-
    tween the mobile station and a first base station. 
    Id. col. 1
    6 ll. 26–33. To initiate the handover, the mobile station
    scans for potential new base stations and measures the
    received signal quality from the potential new base sta-
    tions to identify a base station with the highest signal
    quality (the second base station). 
    Id. col. 1
    6 ll. 6–30. The
    mobile station then sends a handover request message to
    the second base station and waits for a response. 
    Id. col. 1
    6 ll. 26–33. If the second base station accepts the mobile
    station’s handover request, the second base station sends
    a response requesting transfer of the link data from the
    first base station to the second base station, and the
    network transfers the link data. 
    Id. col. 1
    6 ll. 36–60. By
    transferring the link data from the first base station to
    the second base station, the network informs the mobile
    station that the network can transfer the link data.
    Anderson also describes a “break before make” embod-
    iment to prevent interrupted service. Anderson col. 18
    ll. 16–21. In this embodiment, a mobile station that
    suddenly loses its connection with a first base station can
    quickly reacquire the first base station, or acquire a
    different base station (even if no information is available
    8                      IPCOM GMBH & CO.   v. HTC CORPORATION
    after the link with the first base station is lost).     
    Id. col. 1
    8 ll. 16–21.
    III. Global System for Mobile (GSM) Communications
    The Global System for Mobile (GSM) communications
    standard was developed by the European Telecommunica-
    tions Standards Institute (ETSI) to standardize telecom-
    munications protocols.     J.A. 13225.      GSM describes
    reactivating a link with a first base station when a hand-
    over attempt to a second base station is unsuccessful. The
    mobile station sends a “channel request” message to a
    second base station, which responds, in some circum-
    stances, with an “immediate assignment reject” message.
    J.A. 13303. The mobile station then sends a “handover
    failure” message to the first base station and “resumes
    normal operation as if no handover attempt had oc-
    curred.” 
    Id. GSM also
    describes the use of base stations
    that can operate using different generations of radio
    communications standards because it discloses a mobile
    station that can communicate with both “upgraded GPRS
    [General Packet Radio Service] or 2.5G base stations” and
    “pre-existing GSM or 2G-only base stations.” J.A. 19–20.
    IV. Personal Access Communications System Air Inter-
    face Standard (PACS)
    The American National Standards Institute (ANSI)
    adopted and promoted wireless telecommunications
    standards such as the Personal Access Communications
    System Air Interface Standard (PACS) in 1998.
    J.A. 13823, 14842. PACS describes a communications
    system using an Automatic Link Transfer (ALT) handover
    procedure to transfer a mobile station from one base
    station to another base station. J.A. 13969–71. When a
    first base station deems that a handover attempt to a
    different base station is necessary, the first base station
    sends a PERFORM_ALT message to the mobile station to
    force the mobile station to attempt a handover.
    J.A. 13969. The mobile station then issues a handover
    IPCOM GMBH & CO.   v. HTC CORPORATION                   9
    query by sending an ALT_REQ message to a second base
    station. J.A. 13987–88. If the network cannot perform
    the requested transfer, the network responds with an
    ALT_DENY message, and the mobile station “resume[s]
    the conversation on the old link.” J.A. 13976–77. Thus,
    PACS discloses, among other things, (i) a forced handover
    request message (PERFORM_ALT), (ii) a handover query
    message (ALT_REQ), and (iii) a rejection message
    (ALT_DENY). J.A. 11, 13. It also discloses interfacing
    with other networks, such as GSM. J.A. 13885.
    We have jurisdiction under 28 U.S.C. § 1295(a)(4).
    DISCUSSION
    I. Standard of Review
    In construing claims, the Board applies the broadest
    reasonable interpretation consistent with the specifica-
    tion. Cuozzo Speed Techs., LLC v. Lee, 
    136 S. Ct. 2131
    ,
    2142 (2016). “We review intrinsic evidence and the ulti-
    mate construction of the claim de novo.” SightSound
    Techs., LLC v. Apple Inc., 
    809 F.3d 1307
    , 1316 (Fed. Cir.
    2015). “We review the Board’s conclusions of law de novo
    and its findings of fact for substantial evidence.” Blue
    Calypso, LLC v. Groupon, Inc., 
    815 F.3d 1331
    , 1337 (Fed.
    Cir. 2016). Substantial evidence “means such relevant
    evidence as a reasonable mind might accept as adequate.”
    
    Id. (quoting Consol.
    Edison Co. of N.Y. v. NLRB, 
    305 U.S. 197
    , 229 (1938)).
    II. Claim Construction
    We begin with claim construction. Following our
    opinion in HTC Corp. v. IPCom GmbH & Co., KG, 
    667 F.3d 1270
    (Fed. Cir. 2012), the claim limitation “an ar-
    rangement for reactivating the link with the first base
    station” in the ’830 patent is a means-plus-function limi-
    10                     IPCOM GMBH & CO.   v. HTC CORPORATION
    tation. 6 While the Board recognized that ruling, it failed
    to properly construe that limitation. The Board rejected
    IPCom’s proposed three-step algorithm allegedly disclosed
    in the ’830 specification for performing the “arrangement
    for reactivating the link” function, but the Board failed to
    identify what it believed to be the correct algorithm from
    the specification; that omission led to an incomplete
    construction of the claim limitation and is incompatible
    with our holding in In re Donaldson Co., 
    16 F.3d 1189
    ,
    1193 (Fed. Cir. 1994) (en banc).
    In Donaldson, the PTO rejected Donaldson’s claims by
    construing a means-plus-function limitation to encompass
    any means capable of performing the recited function,
    giving no consideration to the content in the specification.
    
    Id. The PTO
    argued that such a practice was permissible
    under the broadest reasonable interpretation standard
    used by the agency. 
    Id. at 1194–95.
    We rejected the
    PTO’s view, holding that the agency must follow the plain
    language of §112 ¶ 6. 7 
    Id. at 1193.
    We explained that the
    construction of a means-plus-function limitation under
    § 112 ¶ 6 “must look to the specification and interpret
    that language in light of the corresponding structure,
    material, or acts described therein, and equivalents
    thereof, to the extent that the specification provides such
    6   In related district court litigation, IPCom asserted
    infringement of the ’830 patent against HTC, and the
    district court case has been stayed pending completion of
    the inter partes reexamination.
    7    Because the ’830 patent was filed before the effec-
    tive date of revisions to 35 U.S.C. § 112 made by The
    Leahy-Smith America Invents Act, Pub. L. No. 112-29,
    §§ 4(c) & 4(e), 125 Stat. 284, 296–97 (2011), the prior
    version of § 112 controls, see MobileMedia Ideas LLC v.
    Apple Inc., 
    780 F.3d 1159
    , 1168 n.3 (Fed. Cir. 2015)
    (applying the pre-AIA version of 35 U.S.C. § 112 ¶ 6).
    IPCOM GMBH & CO.   v. HTC CORPORATION                    11
    disclosure.” 
    Id. We “h[e]ld
    that paragraph six applies
    regardless of the context in which the interpretation of
    means-plus-function language arises, i.e., whether as part
    of a patentability determination in the PTO or as part of a
    validity or infringement determination in a court.” 
    Id. In other
    words, § 112 ¶ 6 “sets a limit on how broadly the
    PTO may construe means-plus-function language under
    the rubric of ‘reasonable interpretation,’” and “the PTO
    may not disregard the structure disclosed in the specifica-
    tion corresponding to such language when rendering a
    patentability determination.” 8 
    Id. at 1194–95.
        In HTC Corp., we explained that HTC and IPCom
    agreed that the “arrangement for reactivating the link”
    recited in the ’830 patent was a means-plus-function
    
    limitation. 667 F.3d at 1278
    . Section 112 ¶ 6 thus re-
    quired the Board to perform a two-step analysis. 
    Id. First, the
    Board had to “identif[y] the particular claimed
    function.” 
    Id. Second, the
    Board had to “look[] to the
    specification and identif[y] the corresponding structure,
    material, or acts that perform that function.” 
    Id. In HTC
    Corp., the district court “concluded that the structure
    corresponding to the ‘arrangement for reactivating [the
    link]’ limitation was ‘a processor connected to a transceiv-
    er and programmed to formulate and send messages to
    reactivate the link, if the handover is unsuccessful.’” 
    Id. We held
    that the district court misstated the law when it
    “stated that disclosure of a processor and transceiver
    8     We also explained that “if one employs means-
    plus-function language in a claim, one must set forth in
    the specification an adequate disclosure showing what is
    meant by that language,” because “[i]f an applicant fails
    to set forth an adequate disclosure, the applicant has in
    effect failed to particularly point out and distinctly claim
    the invention as required by the second paragraph of
    section 112.” 
    Donaldson, 16 F.3d at 1195
    .
    12                     IPCOM GMBH & CO.   v. HTC CORPORATION
    alone was sufficient to provide structure to these claims”
    because “[t]he processor and transceiver amount[ed] to
    nothing more than a general-purpose computer.” 
    Id. at 1280.
    We explained that “[r]ather than relying on the
    processor and transceiver, IPCom had to identify an
    algorithm that the processor and transceiver execute.” 
    Id. We noted
    that although IPCom argued that the ’830
    patent contains such an algorithm, the district court
    never addressed that question “because HTC never asked
    it to do so.” 
    Id. “HTC had
    an opportunity to argue the
    algorithm issue—at IPCom’s invitation—during briefing
    on claim construction and HTC’s summary judgment
    motion, and at oral argument before the district court,”
    yet HTC did not do so. 
    Id. at 1282.
    We held that
    “[b]ecause HTC never attacked the adequacy of the algo-
    rithm in the ’830 patent when given an opportunity to do
    so before the district court,” HTC waived any opportunity
    to raise it on appeal as a basis for invalidating the claims.
    
    Id. at 1283.
        Here, the issue of identifying in the ’830 patent the
    algorithm for performing the “arrangement for reactivat-
    ing the link” function was front and center during the
    reexamination. The Board rejected IPCom’s proposed
    three-step algorithm of: (1) “receiving a rejection from the
    second (i.e., target) base station”; (2) “sending a message
    to the first (i.e., old) base station to maintain the link with
    the first base station”; and (3) “re-establishing the link
    with the first base station by receiving a message from
    that first base station.” J.A. 15. Rather than inquiring
    further into what algorithm (if any) the specification
    actually discloses, however, the Board only questioned
    whether each individual step of IPCom’s proposed algo-
    rithm was separately necessary. For step one, the Board
    found that the specification described an example of an
    “algorithm structure” that “does not involve receiving a
    rejection from the second base station” because “in some
    cases . . . no other base station is receiving.” J.A. 16. For
    IPCOM GMBH & CO.   v. HTC CORPORATION                     13
    step two, the Board cited the specification’s discussion of a
    timer mechanism that purportedly obviated the need for a
    message to be sent to the first base station to reactivate
    the link with the first base station. 
    Id. For step
    three,
    the Board pointed to the specification’s explanation that
    the mobile station “re-registers at its old [base station]
    and keeps its previous settings,” purportedly without
    requiring a receipt of an acknowledgement message from
    the first base station. J.A. 17. The Board then concluded
    its analysis by stating that it “need not consider whether
    or not the combination of Anderson and McDonald dis-
    closes or suggests these method steps.” J.A. 18.
    The Board’s analysis was erroneous because it never
    specified what it believed was the actual algorithm dis-
    closed in the ’830 patent for performing the “arrangement
    for reactivating the link” function. It was not enough for
    the Board to reject the individual steps of IPCom’s pro-
    posed three-step algorithm. As we explained in Don-
    aldson, “the PTO may not disregard the structure
    disclosed in the specification corresponding to such lan-
    guage when rendering a patentability determination.”
    
    Donaldson, 16 F.3d at 1195
    . And in HTC Corp., we held
    that “the functional claiming in claims 1 and 18 of the
    ’830 patent must include an adequate algorithm.” HTC
    
    Corp., 667 F.3d at 1283
    . Here, as in Donaldson, the
    Board never engaged in a comparison of the asserted prior
    art’s disclosure to the “structure” disclosed in the ’830
    patent, due to the Board’s failure to determine what the
    ’830 patent describes as the structure (i.e., the algorithm
    in combination with the processor and transceiver) for
    performing the “arrangement for reactivating the link”
    function. Like Donaldson, the Board here impermissibly
    treated the means-plus-function limitation in its patenta-
    bility analysis as if it were a purely functional limitation.
    We vacate the Board’s claim construction of the “ar-
    rangement for reactivating the link” limitation, and we
    remand for the Board to identify the corresponding algo-
    14                    IPCOM GMBH & CO.   v. HTC CORPORATION
    rithm (if any) in the specification in the first instance,
    consistent with our holdings in Donaldson and HTC Corp.
    Because it never identified any algorithm for the “ar-
    rangement for reactivating the link” limitation, the Board
    also erred by failing to evaluate whether the prior art
    disclosed that algorithm (or its equivalents). J.A. 15–18.
    We therefore vacate and remand the Board’s finding of
    obviousness of claims 1, 18, 30, and 34, and their corre-
    sponding dependent claims.
    III. Obviousness
    We also address here the Board’s findings on the oth-
    er claim limitations—the “forced handover request mes-
    sage,” “handover query,” and “rejection message”—which
    are each recited in claims 18, 30, and 34. J.A. 9–13. We
    then discuss the Board’s rejections of claims 5–17 based
    on the “informing the mobile station” limitation, and the
    Board’s rejections of claims 23 and 25 based on the limita-
    tion reciting different generations of radio communication
    standards, before addressing the motivation to combine
    McDonald, Anderson, GSM, and PACS to arrive at the
    claimed inventions.
    A.
    We first address IPCom’s procedural argument that
    the Board could not rely on GSM and PACS as prior art
    references because HTC did not explain why those refer-
    ences could not have been presented earlier in the pro-
    ceeding. [JA5] After the Board’s decision in the first
    round of review finding the challenged claims of the ’830
    patent unpatentable, IPCom reopened prosecution under
    37 C.F.R. § 41.77(b) and amended its claims in the second
    round of review. Under 37 C.F.R. § 41.77(c), HTC filed
    comments on IPCom’s response and claim amendments,
    raising the GSM and PACS references along with the
    previously relied upon Anderson and McDonald refer-
    ences. J.A. 2–5. IPCom argued to the Board that HTC
    did not explain why the additional prior art could not
    IPCOM GMBH & CO.   v. HTC CORPORATION                   15
    have been raised previously in the proceeding, but the
    Board explained that § 41.77(c) does not require HTC to
    “explain why the additional prior art could not have been
    presented earlier,” when HTC’s comments were filed in
    response to IPCom’s request to reopen prosecution. J.A.
    6.
    We apply “the standards set forth in the Administra-
    tive Procedure Act, 5 U.S.C. § 706” in reviewing the
    Board’s interpretation of PTO regulations. Microsoft
    Corp. v. Proxyconn, Inc., 
    789 F.3d 1292
    , 1306 (Fed. Cir.
    2015). “[W]e set aside actions of the Board that are
    arbitrary, capricious, an abuse of discretion, or otherwise
    not in accordance with law.” 
    Id. “We accept
    the Board’s
    interpretation of [PTO] regulations unless that interpre-
    tation is ‘plainly erroneous or inconsistent with the regu-
    lation.’” 
    Id. (quoting In
    re Sullivan, 
    362 F.3d 1324
    , 1326
    (Fed. Cir. 2004)).
    We agree with the Board, which properly applied its
    regulations to consider GSM and PACS because they were
    cited in response to IPCom’s election to reopen prosecu-
    tion and amend the challenged claims. J.A. 12564–74.
    The Board correctly explained that § 41.77(c) does not
    require HTC to “explain why the additional prior art
    could not have been presented earlier.” J.A. 6. Section
    41.77(c) requires only that HTC’s comments be limited to
    the Board’s decision and issues raised by IPCom’s request
    to reopen prosecution. 9 37 C.F.R. § 41.77(c). When it
    9    Similarly, contrary to IPCOM’s position,
    § 1.948(a) uses the disjunctive “or,” which makes it un-
    necessary for HTC to explain why the additional prior art
    could not have been raised previously.           37 C.F.R.
    § 1.948(a)(2). Section 1.948(a) provides that a third party
    requester may only cite additional prior art:
    16                      IPCOM GMBH & CO.   v. HTC CORPORATION
    reopened prosecution, IPCom amended claims 5, 12, 16,
    18, 23, 25, 30, and 34 (and their dependent claims) to
    include the “forced handover request message,” the
    “handover query,” the “rejection message,” the “informing
    the mobile station” limitation, and different generations
    of radio communications standards. 10 J.A. 12564–74. We
    affirm the Board’s finding that it could properly consider
    (1) which is necessary to rebut a finding of fact by
    the examiner;
    (2) which is necessary to rebut a response of the pa-
    tent owner; or
    (3) which for the first time became known or
    available to the third party requester after the fil-
    ing of the request for inter partes reexamination
    proceeding. Prior art submitted under paragraph
    (a)(3) of this section must be accompanied by a
    statement as to when the prior art first became
    known or available to the third party requester
    and must include a discussion of the pertinency of
    each reference to the patentability of at least one
    claim.
    37 C.F.R. § 1.948 (emphasis added). Thus, § 1.948(a)
    allows HTC to cite additional prior art if that prior art “is
    necessary to rebut a response of the patent owner.” 
    Id. 10 Although
    the “arrangement for reactivating the
    link” limitation was not an amendment to the challenged
    claims, IPCom sought a new construction of this limita-
    tion based on “new evidence in th[e] reexamination; it was
    not available when [IPCom] filed its [earlier] responses.”
    J.A. 12473–75, 12582. HTC properly responded to IP-
    Com’s new argument on the “arrangement for reactivat-
    ing the link” limitation. On remand, the Board should
    identify the correct algorithm for this limitation and
    determine whether the prior art discloses that algorithm.
    IPCOM GMBH & CO.   v. HTC CORPORATION                  17
    GSM and PACS against IPCom’s request to reopen prose-
    cution and amend the claims. 11
    B.
    We now turn to whether the prior art discloses the
    claim limitations in dispute other than the “arrangement
    for reactivating the link” limitation. The Board agreed
    with HTC that PACS discloses a “forced handover request
    message” by describing a PERFORM_ALT message that
    is transmitted from the network to a mobile station. J.A.
    11. It also agreed that PACS discloses a “handover query”
    by describing an ALT_REQ message and a “rejection
    message” by describing an ALT_DENY message. J.A. 13.
    We agree with the Board. We note that IPCom con-
    cedes that PACS discloses that the PERFORM_ALT
    message is forced, i.e., mandatory, but IPCom argues that
    PACS never teaches the possibility of reactivating the
    link if the handover is unsuccessful, which, in IPCom’s
    view, is part of the “forced handover request message”
    limitation. Appellant Br. 54; Reply Br. 24. IPCom is
    incorrect; the Board correctly explained that reactivating
    the link and the forced handover request message are
    separate claim limitations. J.A. 11. It also noted that
    IPCom did not challenge HTC’s argument that PACS
    discloses the “handover query” and “rejection message,”
    11  IPCom argues that it had no opportunity to sub-
    mit rebuttal evidence with respect to GSM and PACS.
    Reply Br. 21–23. The Board explained to IPCom in its
    second round decision, however, that the rejections based
    on GSM and PACS were new grounds of rejection that
    would allow IPCom to reopen prosecution. J.A. 20–21.
    IPCom had the opportunity to reopen prosecution just as
    IPCom did after the first round before the Board in which
    the Board adopted new grounds of rejection, but IPCom
    chose not to do so.
    18                   IPCOM GMBH & CO.   v. HTC CORPORATION
    
    id. at 13,
    and IPCom does not challenge these findings on
    appeal. Appellant Br. 42–44; Reply Br. 13–16, 24. Thus,
    we affirm the Board’s findings that PACS discloses the
    “forced handover request message,” the “handover query,”
    and the “rejection message” limitations.
    C.
    Next, we turn to claims 5–17 and find no error in the
    Board’s analysis of the “informing the mobile station”
    limitation. The Board explained that claim 5, as amend-
    ed, recites “informing the mobile station whether the
    network is capable of transferring the link data from the
    first base station to the second base station.” J.A. 6.
    IPCom argued independent claims 5, 12, and 16 and their
    dependent claims to the Board as a group, and the Board
    treated claim 5 as representative. 
    Id. The Board
    found
    that McDonald’s “busy OSW” signal informs the mobile
    station that the network cannot transfer the link data
    from the first base station to the second base station.
    J.A. 7. It also found that Anderson disclosed a successful
    handover, which informs the requesting mobile station
    that the network could perform the transfer. 
    Id. The Board
    found that combining Anderson and McDonald
    would have disclosed informing the mobile station wheth-
    er a network was capable of handover because it would
    achieve both alternatives: successful and unsuccessful
    handover messages. J.A. 7–8.
    We agree that substantial evidence supports the
    Board’s finding that the combination of Anderson and
    McDonald teaches the recited “informing the mobile
    station” limitation because Anderson teaches a successful
    handover, and McDonald describes cases in which hando-
    ver is unsuccessful by using a busy OSW signal. Under
    the broadest reasonable construction, a combined system
    that can indicate either a successful handover using the
    features of Anderson or that no handover is possible using
    the features of McDonald is sufficient to meet the re-
    IPCOM GMBH & CO.   v. HTC CORPORATION                   19
    quirements of the claims, which only recite that the
    network informs the mobile base station whether a hand-
    over is possible. We affirm the Board’s findings that
    combining Anderson and McDonald discloses the inform-
    ing the mobile station limitation.
    D.
    We next address the claim limitations calling for the
    use of different generations of radio communications
    standards recited in claims 23 and 25. 12 These claims
    recite that “the first base station and the second base
    station operate in respective parts of the network using
    different generations of radiocommunications standards
    for radio communication with the mobile station.” J.A.
    12571–72. The Board rejected claims 23 and 25 in view of
    Anderson, McDonald, and GSM. J.A. 18–20. The Board
    credited HTC’s argument that GSM disclosed “a mobile
    station that is capable of communicating with upgraded
    GPRS or 2.5G base stations, as well as pre-existing GSM
    or 2G-only base stations.” J.A. 19–20. It found that the
    base stations need not be incapable of communicating
    among themselves to facilitate handover, even if the
    specification discloses such an example, because the
    example from the specification should not be imported
    into the claims. J.A. 19–20.
    IPCom argues on appeal that because the specifica-
    tion shows an example of different base stations that
    cannot communicate directly with each other when the
    base stations use different generations of radio communi-
    cation standards, ’830 patent col. 6 ll. 57–64, a person of
    ordinary skill in the art would understand claims 23 and
    25 to require that those base stations be unable to com-
    municate directly. Appellant Br. 52, 54–56. IPCom also
    12  Claim 23 depends on claim 1 and claim 25 de-
    pends indirectly on claim 5. J.A. 12565–72.
    20                    IPCOM GMBH & CO.   v. HTC CORPORATION
    argues that claim 5 (from which claim 25 indirectly de-
    pends) requires the same result because claim 5 recites
    that the mobile station transmits link data to a second
    base station “if the network cannot transfer the link
    data.” Appellant Br. 54; J.A. 12567. IPCom contends
    that this limitation is missing from GSM because the base
    stations with and without GPRS in GSM can communi-
    cate directly with each other. Appellant Br. 55.
    We disagree. We find that substantial evidence sup-
    ports the Board’s findings that GSM teaches the recited
    limitation of using different generations of radio commu-
    nications standards because, as the Board found, GSM
    discloses using a mobile station that can communicate
    with both GSM/2G and GPRS/2.5G base stations, a find-
    ing that IPCom does not challenge. J.A. 19–20. Contrary
    to IPCom’s position, claims 23 and 25 do not require that
    the base stations be incapable of communicating with
    each other; the claims simply require that the first and
    second base stations operate “using different generations
    of radiocommunications standards for radio communica-
    tion with the mobile station.” J.A. 12571–72. We agree
    that the specification’s example of base stations incapable
    of communicating among themselves to facilitate hando-
    ver should not be imported into claims 23 and 25. 13
    We also address IPCom’s argument relating to claim
    5, from which claim 25 indirectly depends through claim
    11. Claim 5 does not require that the base stations be
    unable to transfer link data directly because it covers both
    networks that are capable of transferring link data and
    ones that are not capable of transferring link data.
    J.A. 12567. Claim 5 recites “causing the mobile station to
    13 Because claim 23 depends from claim 1, which re-
    cites the “arrangement for reactivating the link” limita-
    tion, the Board must resolve this limitation from claim 1
    before it can determine claim 23’s patentability.
    IPCOM GMBH & CO.   v. HTC CORPORATION                    21
    transmit the link data to the second base station, if the
    network cannot transfer the link data.” 
    Id. Claim 11
    depends on claim 5, and claim 11 recites “causing the first
    base station to transfer the link data to the second base
    station if the network can transfer link data.”
    J.A. 12567–68. Thus, claim 5 does not require that the
    network be unable to transfer link data, but it encom-
    passes both types of networks—ones that can transfer the
    link data and ones that cannot transfer the link data—
    because claim 5 must include the scope of claim 11. We
    reject IPCom’s argument that the base stations “using
    different generations of radiocommunications standards
    for radio communication with the mobile station” must be
    incapable of communicating directly with each, and we
    affirm the Board’s finding that GSM discloses this limita-
    tion.
    E.
    We turn last to the motivation to combine McDonald,
    Anderson, GSM, and PACS. The Board rejected IPCom’s
    arguments that it would not have been obvious to a
    person of ordinary skill in the art to combine either GSM
    or PACS with Anderson and McDonald based on the
    length of the references or because the combination would
    be inoperable.       J.A. 13.     The Board found that
    (1) Anderson and McDonald disclose methods of handover
    in a mobile telephone system; (2) GSM discloses a tech-
    nical specification for handover procedures for mobile
    stations; and (3) PACS discloses mobile applications that
    include communications and handover methods among
    network components (e.g., PERFORM_ALT). J.A. 14. It
    further found that combining the known systems of
    handover for mobile stations in Anderson or McDonald
    with systems for handover discussed in GSM and PACS
    would have been obvious because it would have yielded no
    more than a predictable result. 
    Id. (citing KSR
    Int’l Co. v.
    Teleflex Inc., 
    550 U.S. 398
    , 416 (2007)).
    22                     IPCOM GMBH & CO.   v. HTC CORPORATION
    IPCom argues that the Board engaged in impermissi-
    ble hindsight to combine the references in the precise
    manner claimed by the ’830 patent. IPCom contends that
    combining these references would not have yielded pre-
    dictable results because Anderson relates to a system
    where the mobile system controls the handover, McDon-
    ald relates to a system where the user enters input that
    guides the handover, and GSM relates to a handover in
    which the network is in control. IPCom does not argue
    which entity is in control in PACS.
    Substantial evidence supports the Board’s motivation
    to combine findings. Both Anderson and McDonald teach
    solutions for solving the problem of an unsuccessful
    handover in a cellular telephone network, and each teach
    a means for returning to a first base station after a failed
    handover attempt to a second base station. As discussed
    above, McDonald teaches a method for a mobile station to
    return to the first base station after a failed handover
    attempt. McDonald col. 3 ll. 14–21. Similarly, Anderson
    discloses a “break before make” embodiment to prevent
    interrupted service, in which a mobile station that sud-
    denly loses its connection with a first base station can
    quickly reacquire the first base station or acquire a differ-
    ent base station after a failed handover attempt. Ander-
    son col. 18 ll. 16–24. A person of ordinary skill in the art
    would have been motivated to combine these teachings to
    solve the common problem of unsuccessful handovers.
    J.A. 13–14. Combining McDonald with Anderson’s “make
    before break” embodiment also teaches the “informing the
    mobile station” limitation, as we discuss above. J.A. 6–8.
    Anderson further discloses that its communication
    system can be combined with a GSM network. Anderson
    col. 4 ll. 40–44. McDonald contains a similar disclosure in
    its reference to “TDM time slots” because HTC’s expert
    explained that at the time of the invention, “GSM was a
    common cellular protocol using TDM time slots.” J.A.
    12791–92; McDonald col. 1 ll. 24–26. Adding GSM to
    IPCOM GMBH & CO.   v. HTC CORPORATION                    23
    Anderson and McDonald teaches the limitation of using
    different generations of radio communication standards in
    a cellular telephone network because GSM discloses using
    a mobile station that can communicate with both GSM/2G
    and GPRS/2.5G base stations. J.A. 19–20.
    A person of ordinary skill would also have been moti-
    vated to combine Anderson or McDonald with PACS.
    Anderson describes a mobile-centric system designed to
    connect with different networks. Anderson col. 1 ll. 18–
    21, col. 4 ll. 40–51. The crossover between McDonald and
    PACS was also readily apparent for the same reasons. As
    discussed above, PACS discloses a “forced handover
    request message” by describing a PERFORM_ALT mes-
    sage transmitted from the network to a mobile station, a
    “handover query” by describing an ALT_REQ message,
    and a “rejection message” by describing an ALT_DENY
    message. J.A. 11, 13–14. PACS itself further discloses
    interfacing with GSM. J.A. 13885.
    The Board correctly explained that both McDonald
    and Anderson disclose methods of handover for mobile
    telephone systems (including the “informing the mobile
    station” limitation), GSM discloses using a mobile station
    that can communicate with both GSM/2G and GPRS/2.5G
    base stations (which are different generations of radio
    communication standards), and PACS discloses using
    communication messages between base stations and
    mobile stations (including a forced handover request
    message, a handover query, and a rejection message).
    J.A. 14. In light of their interrelated teachings, combin-
    ing these four known systems for handover and handoff
    for cellular telephone systems would have resulted in no
    more than the predictable result for a system for handing
    over mobile stations between base stations, consistent
    with the GSM and PACS industry standards. 
    Id. For these
    reasons, we affirm the Board’s factual find-
    ings that the prior art discloses all the limitations of the
    24                     IPCOM GMBH & CO.   v. HTC CORPORATION
    challenged claims on appeal, except for the “arrangement
    for reactivating the link” means-plus-function limitation.
    We also affirm the Board’s finding of a motivation to
    combine McDonald, Anderson, GSM, and PACS to arrive
    at the combinations recited in the challenged claims
    except for the “arrangement for reactivating the link”
    limitation. We vacate and remand the Board’s findings on
    the “arrangement for reactivating the link” limitation.
    IV. The Board’s Rejection of Claims 31–37
    We briefly address IPCom’s arguments that the Board
    lacked jurisdiction to consider the patentability of claims
    31–37 during its second round of review. In its first
    decision in the reexamination proceeding, the Board did
    not address whether claims 31–37 should be regarded as
    obvious, J.A. 12475–76, as HTC had not expressly chal-
    lenged those claims for obviousness in its first Notice of
    Appeal to the Board. 14 J.A. 8670–71. After the Board’s
    first decision, IPCom reopened prosecution of claims 1, 5–
    26 and 28–37 and amended these claims, and HTC re-
    sponded that the amended claims were unpatentable.
    J.A. 3, 5.
    After IPCom filed its request to reopen prosecution in
    view of the Board’s initial decision, the Board issued its
    Order Remanding Inter Partes Reexamination under 37
    CFR 41.77(d) to the Examiner, granting IPCom’s request
    to enter “claim amendments to claims 5, 12, 16, 18, 23, 25,
    30, and 34” and ordering that “[t]his matter will be re-
    manded to the Examiner for consideration of claims 1 and
    5–37 in view of the newly submitted claim amendments,
    14 HTC’s first Notice of Appeal did challenge the Ex-
    aminer’s refusal to maintain rejections of claims 30–37
    under 35 U.S.C. § 305 as enlarging the scope of the
    claims, J.A. 8671, but HTC did not maintain this argu-
    ment in its appeal brief to the Board. J.A. 8814–25.
    IPCOM GMBH & CO.   v. HTC CORPORATION                   25
    the declaration of [IPCom’s expert], and Requester’s
    response pertaining to the new grounds of rejection as
    enumerated in our prior Decision.” J.A. 14422. The
    Board expressly explained that “[a]s Patent Owner ob-
    serves (Request, p. 14), the new ground of rejection ap-
    plies to claims 1 and 5–37.” J.A. 14422 n.1. The
    Examiner then reviewed claims 1 and 5–37 in light of the
    new amendments, J.A. 14541, 14754, and found, as rele-
    vant here, claims 31–37 patentable based on IPCom’s
    amendments. 15 J.A. 14547–48, 14757–61.
    IPCom argues that when the reexamination returned
    to the Board for the second time, the Board lacked juris-
    diction to consider the obviousness of claims 31–37 be-
    cause, even though IPCom amended those claims when it
    reopened prosecution, claims 31–37 had not been part of
    the first Board appeal. There certainly was some confu-
    sion below about the impact of the Board’s first decision
    on claims 31–37. For example, IPCom itself stated on the
    record below, after receiving the Board’s first decision,
    that it “presume[d] that the Board intended to reject all
    claims that were subject to appeal, namely claims 1 and
    5–37.” J.A. 12577 n.1. IPCom’s initial reaction to the
    Board’s first decision is not surprising, since the Board’s
    logic in rejecting claims 1, 5–26, and 28–30, appears to
    apply equally to claims 31–37. J.A. 12471–75.
    More importantly, when IPCom reopened prosecution,
    it amended all of the pending claims, including claims 31–
    37. J.A. 12565–76. IPCom amended independent claims
    30 and 34 to add the forced handover request, handover
    15   When the reexamination returned to the Board,
    the Board reversed, initially addressing only claims 1 and
    5–30, J.A. 15688, 15692, but it later issued a replacement
    decision, clarifying that IPCom had reopened prosecution
    of claims 1, 5–26, and 28–37, and it found those claims
    unpatentable. J.A. 2–5.
    26                    IPCOM GMBH & CO.   v. HTC CORPORATION
    query, and rejection message limitations. J.A. 12572–74.
    IPCom also for the first time raised its claim construction
    argument on the “arrangement for reactivating the link”
    limitation in claims 1 and 18, a limitation that is also
    recited in both claims 30 and 34. J.A. 12565–74. IPCom
    explained that this construction was “new evidence in this
    examination; it was not available when the Patent Owner
    filed its [prior] responses.” J.A. 12582. Although depend-
    ent claims 31–33 and 35–37 were not directly amended,
    they were indirectly amended because they depend on
    amended claim 30 or 34. J.A. 12572–74. By amending
    claims 31–37, IPCom altered the scope of these claims,
    and this opened the door to permit HTC to challenge the
    amended claims.
    IPCom also argues that the Board lacked jurisdiction
    to consider claims 31–37 because HTC’s notice of appeal
    in the first Board appeal did not challenge claims 31–37
    as to obviousness. J.A. 8670–71. However, IPCom cites
    no authority (other than an inapposite Board decision
    that found that a proposed obviousness rejection was
    waived) 16 to support IPCom’s argument that the Board’s
    jurisdiction in the second round before the Board is lim-
    ited by HTC’s Notice of Appeal in the first round. Reply
    Br. 26–27. We find that in its second decision (which is
    the one on appeal), the Board properly considered HTC’s
    challenge to claims 31–37 after IPCom had reopened
    prosecution and amended those claims.
    16 Google Inc. v. Netlist, Inc., No. 2014-007777, 
    2015 WL 799035
    , at *8 (P.T.A.B. Feb. 24, 2015) (finding that a
    requester’s arguments opposing an examiner’s nonadop-
    tion of a proposed rejection for obviousness were waived
    because the requester did not identify that issue in its
    Notice of Cross Appeal).
    IPCOM GMBH & CO.   v. HTC CORPORATION                    27
    CONCLUSION
    For the foregoing reasons, we affirm in part, vacate in
    part, and remand for consideration in light of this opinion.
    We vacate and remand the Board’s finding of obviousness
    of independent claims 1, 18, 30, and 34, and their corre-
    sponding dependent claims based on the “arrangement for
    reactivating the link” means-plus-function limitation. We
    affirm the Board’s findings that the prior art discloses all
    the other limitations of the challenged claims on appeal,
    and the motivation to combine McDonald, Anderson,
    GSM, and PACS to arrive at claims 5–17 and 25. We
    affirm the Board’s finding of obviousness with respect to
    claims 5–17 and 25.
    AFFIRMED-IN-PART, VACATED-IN-PART, AND
    REMANDED
    COSTS
    No costs.