The Patent Court revisits IPXL doctrine regarding prohibition on hybrid claiming

Rob Raheja | February 29, 2012

HTC Corporation v. IPCom GmbH & Co.

January 30, 2012

Panel:  Bryson, Linn and O’Malley.  Opinion by O’Malley.


HTC Corporation and HTC America, Inc. sued IPCom GmbH & Co., KG seeking a declaration that it did not infringe claims of IPCom patents. IPCom counterclaimed alleging infringement. HTC moved for summary judgment of invalidity on the ground that claims 1 and 18 of U.S. Patent No. 6,879,830 owned by IPCom were indefinite because (1) they claimed both an apparatus and method steps; and (2) the means-plus-function limitation “arrangement for reactivating,” found in the last paragraph of claims 1 and 18, was indefinite because the patent failed to disclose structure corresponding to the claimed function. On summary judgment, the district court agreed with HTC that claims 1 and 18 were indefinite based on the Federal Circuit’s precedent in IPXL Holdings, L.L.C. v., Inc prohibiting hybrid claiming of apparatus and method steps in the same claim, but rejected HTC’s argument that the claims were indefinite for failing to disclose the structure corresponding to the means-plus-function limitation. On appeal, the Federal Circuit reversed the district court’s judgment of invalidity based on hybrid claiming, but did not disturb the district court’s finding regarding the means-plus-function limitation. The Federal Circuit held that the district court misconstrued the asserted claims and that the patent did not describe any improper hybrid claiming of apparatus and method steps in the same claim because the claims, when properly construed, were drawn to only an apparatus and the prohibition on hybrid claiming under IPXL was inapplicable to claims 1 and 18.


“The ‘830 patent covers a handover in a cellular telephone network. A cellular telephone–called a “mobile station” in the patent–maintains a link with a tower–called a “base station.” A handover occurs when a mobile station switches from one base station to another. This happens, for example, when a person using a cellular telephone travels in a car between coverage areas. The invention, in principle, reduces the chance of interrupted service during a handover.”

Claims 1 and 18 recite as follows:

[1] A mobile station for use with a network including a first base station and a second base station that achieves a handover from the first base station to the second base station by:

[2] storing link data for a link in a first base station,

[3] holding in reserve for the link resources of the first base station, and

[4] when the link is to be handed over to the second base station:

[5] initially maintaining a storage of the link data in the first base station,

[6] initially causing the resources of the first base station to remain held in reserve, and

[7] at a later timepoint . . . deleting the link data from the first base station and freeing up the resources of the first base station, the mobile station comprising:

[8] an arrangement for reactivating the link with the first base station if the handover is unsuccessful.

(Emphasis and numbered paragraphs [1] to [8] in original).

Hybrid claiming issue

The issue on appeal was whether the mobile station or the network, as emphasized in paragraph 1 of representative claim 1 above, implemented the six functions recited in paragraphs 2-7. In other words, if the mobile station implemented said six functions recited in the claims, the claims would be indefinite because they would recite both an apparatus – the mobile station – and method steps – the functions enumerated in paragraphs 2-7. However, if the network performs the functions, the claims are not indefinite because the claims merely describe the network environment in which mobile station must be used.

First, the Federal Circuit found that the district court erred in construing the plain language of claims 1 and 18. “The plain language of claims 1 and 18 indicates that the network, not the mobile station, performs the enumerated functions.” This is because “the phrase beginning with ‘including’ and the clause beginning with ‘that achieves’ modify ‘network’ as modifier are generally placed next to the words they modify. William Strunk, Jr. & E.B. White, The Elements of Style 30 (4th edition 2000).”

Furthermore, Judge O’Malley writing for the court noted that “the network, not the mobile station, performs the enumerated functions” is supported by the fact that “the claims re-introduce the mobile station in paragraph 7 after the enumerated functions. The mobile station is followed by a functional limitation in paragraph 8: ‘the mobile station comprising . . . an arrangement for reactivating the link with the first base station if the handover is unsuccessful.’ The claims would read in a disjointed manner if they were to recite the mobile station in the first paragraph, modify the mobile station with the six enumerated functions, and then, without a transition, recite the mobile station again in paragraph 7, followed by yet another modifier. Had the claim drafter intended that format, the drafter likely would have followed the recitation of the mobile station in paragraph 7 with “further comprising” instead of “comprising” to signal that additional modification would be attached to the mobile station.” (Emphasis in original, citations omitted).

Second, the Federal Circuit faulted the district court for failing to look to the specification in properly construing the claims because the specification confirmed that the network, rather than the base station, performed the six functions.

Third, although the Federal Circuit acknowledged that the district court was correct in considering the prosecution history, it disagreed with the district court because it placed too much weight on the Applicants’ use of the word “process” in an Office Action response as an acknowledgement that claims 1 and 18 recite method steps. More specifically, in an Office Action response, the applicants of the ‘830 patent distinguished a prior art reference that the Examiner cited by arguing that “the cited section of [the prior art reference] clearly describes a process that is completely different from the claimed process …” App. 46 (Emphasis and Brackets in original).

The Federal Circuit found that the remarks made by the patentee during the prosecution did not rise to a level sufficient to support a finding that the patentee disavowed a particular claim scope. Citing Phillips v. AWH Corp., the Federal Circuit stated that “Claim language and the specification carry greater weight than the prosecution history. ‘[B]ecause the prosecution history represents an ongoing negotiation between the PTO and the applicant, rather than the final product of that negotiation, it often lacks the clarity of the specification and thus is less useful for claim construction purposes.’ An attorney’s single reference to a ‘process’ in the office action response is unpersuasive when weighed against the plain language of the claims and the specification, both of which clearly indicate that the enumerated functions are part of the network environment.”

The Federal Circuit noted that when claims 1 and 18 are properly construed as noted above, they do not contravene its holding in IPXL Holdings, L.L.C. v., Inc. prohibiting hybrid claiming.

The claim at issue in IPXL read as follows:

The system of claim 2 [including an input means] wherein the predicted transaction information comprises both a transaction type and transaction parameters associated with that transaction type, and the user uses the input means to either change the predicted transaction information or accept the displayed transaction type  and transaction parameters.

In IPXL, the Federal Circuit held “the claim indefinite because the claim failed to make clear whether infringement would occur ‘when one creates a system that allows the user to change the predicted transaction information or accept the displayed transaction, or whether infringement occurs when the user actually uses the input means to change transaction information or uses the input means to accept a displayed transaction.’ The IPXL claim, in other words, was ambiguous because it recited both a system that allowed a user to practice a method step and the user’s practicing the method step. Claims 1 and 18 are different. They do not recite a mobile station and then have the mobile station perform the six enumerated functions. The claims merely establish those functions as the underlying network environment in which the mobile station operates.” (Citations omitted).

The Federal Circuit found Claims 1 and 18 similar to a claim they found definite in Microprocessor Enhancement Corp. v. Texas Instruments, Inc. (“MEC”), in which the claim recited as follows:

A method of executing instructions in a pipelined processor comprising: [structural limitations of the pipelined processor]; the method further comprising: [method steps implemented in the pipe-lined processor].

Like the MEC claim, in which the direct infringement was limited to practicing the claimed method in the pipelined processor possessing the required structure, claims 1 and 18 of the IPCom patent “make clear that infringement occurs when one makes, uses, offers to sell, or sells the claimed apparatus: the mobile station–which must be used in a particular network environment.”

Last but not least, under the proper claim construction, the Federal Circuit found that, like the MEC claim, the claims 1 and 18 in this case are drafted using an unconventional format what the MEC court called a “preamble-within-a-preamble” format.

As a side note, this finding could create trouble for IPCom if the district court decides to re-open this case under its discretionary power. This is because, under the “preamble-within-a-preamble” format, claims 1 and 18 are drawn to only one means-plus-function element. MPEP 2164.08(a) defines a single means claim as follows: “A single means claim, i.e., where a means recitation does not appear in combination with another recited element of means, is subject to an undue breadth rejection under 35 U.S.C. 112, first paragraph. In re Hyatt, 708 F.2d 712, 714-715, 218 USPQ 195, 197 (Fed. Cir. 1983) (A single means claim which covered every conceivable means for achieving the stated purpose was held nonenabling for the scope of the claim because the specification disclosed at most only those means known to the inventor.). When claims depend on a recited property, a fact situation comparable to Hyatt is possible, where the claim covers every conceivable structure (means) for achieving the stated property (result) while the specification discloses at most only those known to the inventor.” (Emphasis added).

Means-plus-function issue:

HTC argued that the specification did not disclose sufficient structure to practice the algorithm, but did not attack the sufficiency of the algorithm.  On summary judgment, “[t]he district court concluded that the structure corresponding to the ‘arrangement for reactivating’ limitation was ‘a processor connected to a transceiver and programmed to formulate and send messages to reactivate the link, if the handover is unsuccessful.’”

On appeal, the Federal Circuit pointed out that the district court was wrong when it concluded that a person of ordinary skill in the art would understand a processor and transceiver alone to be sufficient structure corresponding to the “arrangement for reactivating” limitation.  However, because HTC waived any attack on the algorithm, it held that “the district court correctly concluded that the ‘830 patent’s specification adequately disclosed a processor and transceiver for use in performing the function claimed in claims 1 and 18.”

Prosecution Tips

To avoid the hybrid claiming problem, apparatus claims should be drafted to suggest capabilities and not actual use. That is, an apparatus must be capable of performing functionality recited in apparatus claims without requiring actual performance or use. When possible, avoid reciting functionality of the claimed element of an apparatus using active tense (-ing form).  Rather, use language such as “element to perform [functional language]”, “element configured to perform [functional language]”, “element adapted to perform [functional language]”. Even the use of the language “element for performing [function]” is okay as long as the “element” recited is a sufficiently definite structure to avoid invocation of section 112, paragraph 6 limitation. Obviously, avoid using a single means claim. Importantly, whenever a computer/processor makes up the claimed elements, always ensure that an algorithm supporting the structure is described in the specification. Also, it should be noted that the algorithm requirement may not be satisfied by merely describing in the specification and/or in the claims, in functional terms, as to what an element does without describing in the specification how it does it. For other examples of hybrid claiming see In re Katz (Fed. Cir. 2011) and Ex parte Lyell.


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