Cell Phone Network Patent Survives § 112 Attacks in Federal Circuit

By Chris Reaves

HTC Corporation v. IPCom GmbH & Co., KG, No. 2011-1004, Fed. Cir. Jan. 30, 2012

In a recent infringement suit, a patent for a cell phone network mobile station narrowly survived several attempts at invalidation through indefiniteness.  The Federal Circuit applied numerous rules of claim interpretation, especially for means-plus-function claims, and reminded the defense of the importance of addressing all issues at the trial level.  The case serves as a good lesson in “what not to do” for both prosecutors and litigants.

Background

IPCom GmbH & Co., KG owns US Patent No. 6,879,830 (‘830) and other patents, which go to cell phone networks and their methods.  ‘830 in particular discusses an efficient cellular phone network “handover” – the process by which one cell tower takes over a call from another as the phone moves from place to place.

IPCom and the HTC Corporation countersued each other for, respectively, infringement of three of IPCom’s patents, including ‘830, and declaration of non-infringement.  During the trial’s Markman hearing, HTC moved for summary judgment of invalidity of ‘830 claims 1 and 18.  The district court found that the means-plus-function portion of these claims had the required corresponding structure.  However, it also found that the claims included both method steps and an apparatus, making them indefinite under the rule of IPXL Holdings v. Amazon.com.  It therefore invalidated both claims.

On stipulation of the parties, the decision was promptly declared final and certified for appeal under Fed. R. Civ. P. 54(b).  Judges Bryson, Linn, and O’Malley of the Federal Circuit heard the appeal.

IPXL Indefiniteness Does Not Apply to “Preamble-Within-A-Preamble”

Claim 1 of ‘830 recites, in total:

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:

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:

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 mobile station comprising:

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

Claim 18 and, by stipulation, claim 16 differ only in ways “immaterial to this appeal.”

The district court had construed the claims to state that the mobile station “achieves a handover” which is then described as a series of steps.  Because the claim described the mobile station both in terms of this method and separately in terms of “an arrangement,” the court therefore invalidated it as indefinite.

The Federal Circuit, however, determined that the “that achieves a handover” clause described “network”, not “mobile station.”  First, “[m]odifiers should be placed next to the words they modify”, and the clause was closer to “network.”  Second, the repetition of “mobile station” in the seventh paragraph “would read in a disjointed manner” if the preceding functions also referred to the mobile station.  And third, the specification confirmed that the base stations of the network, not the mobile station, perform the functions in the handover.

HTC and the district court both tried to overcome this language by pointing to the prosecution history, but the Federal Circuit recalled Phillips v. AWH for the principle that prosecution “often lacks the clarity of the specification and thus is less useful for claim construction purposes.”  Although the applicants had referred to the “claimed process” of claim 1 during prosecution, the Federal Circuit found this insufficient to overcome the “plain language of the claims and the specification” that showed the mobile station was an apparatus.  A single reference to “steps” was similarly unpersuasive.

As the claims did not claim both the apparatus and the process, the Federal Circuit ruled that they did not violate the rule of IPXL.  They were instead merely in a “preamble-within-a-preamble” form, which was “unconventional” but valid under Microprocessor Enhancement Corp. v. Texas Instruments.

General Structure for Means-Plus-Function Claims May Be Implied, Not Explicit

The court then examined HTC’s alternate argument that the claims were indefinite under § 112 ¶ 6.  The parties had agreed that the “arrangement for reactivating” in all three claims was a means-plus-function limitation, which requires disclosure of a corresponding structure in the specification.  But the district court found, and the Federal Circuit agreed, that no literal disclosure was necessary, because a person skilled in the art “would understand that the mobile device would have to contain a processor and transceiver.”  Expert testimony, including the deposition of HTC’s own expert, supported this assessment.

The Federal Circuit also noted that a detailed hardware configuration was not necessary; “reference to such general-purpose processors will suffice” to make the claim definite if the description also discloses an algorithm that “describe[s] a means for achieving [the reactivating] outcome, not merely the outcome itself.”  At the trial level, HTC had argued exclusively that the hardware disclosure was insufficient with or without algorithms, and did not contend in the alternate that the disclosed algorithms were inadequate, even when IPCom argued in briefs that they were.  Therefore, the Federal Circuit did not let HTC raise the argument on appeal, finding no reason not to apply the general appellate policy against considering issues not raised at trial.

With no other cause to invalidate, the panel reversed, declaring all claims valid.

Post-Case Analysis

The Federal Circuit creates little new law here, but reminds us of some existing principles for both prosecutors and litigators.  Prosecutors are reminded of the importance of clarity in drafting.  Although IPCom’s claims survived their second interpretation, clearer attachment of nouns to modifiers would have avoided the initial invalidation.  Simple use of commas or semi-colons to break up the clauses, and then leading each clause with its own element, can be an invaluable rule of thumb.  For instance, opening with “A mobile station for use with a network, the network including…” would have made it undeniable what the following paragraphs referred to.

Similarly, although the courts will treat a structure as implicitly disclosed when it is “understood” by those skilled in the art, it is better to be explicit.  What is “understood” can vary from expert to expert, and had HTC’s own expert not admitted to the validity of IPCom’s position, the patent might well have failed on this point.  Also, this rule has less benefit when the structure is not a processor or similar; that is, one that must be thoroughly defined on its own terms instead of in the context of algorithms.

Means-plus-function claims are especially vulnerable to a few mistakes that IPCom nearly stumbled over.  Prosecutors should always remember to check their claims for IPXL-style indefiniteness, as the drafter is already thinking in terms of the corresponding process and may forget to make the distinction.  Double-checking for the appropriate structure for each function – including the algorithm, if software is involved – is also vital.

Finally, in all cases, proofreading is key.  A second pair of eyes to check for these and other mistakes during drafting can save your client from both a higher risk of invalidity and unnecessary legal fees the first time he tries to enforce.

Litigators, meanwhile, are reminded of the importance of attacking the opponent from every reasonable angle; in this case, to challenge the structure disclosure on both hardware and software.  It is sometimes splitting hairs to say what specific sub-(sub-sub-)issues a party has failed to address, and HTC might have argued that, by bringing up structure disclosure at all, they preserved all aspects of it for appeal.  But at minimum, once IPCom reminded HTC of the algorithm issue in its own briefs, HTC needed to respond.  Leaving that argument unchallenged cost them dearly.

The opinion is available at: http://www.cafc.uscourts.gov/images/stories/opinions-orders/11-1004.pdf

Oral arguments may be heard at: http://oralarguments.cafc.uscourts.gov/default.aspx?fl=2011-1004.mp3

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