Claim Construction

Bill Schertler | March 18, 2015

Fenner Investments, LTD., v. Cellco Partnership (doing business as Verizon Wireless)

February 12, 2015

Before: Newman, Schall and Hughes. Opinion by Newman.


Fenner owns US Patent No. 5,561,706 (the ‘706 patent) directed to a personal communications services (PCS) system that permits users to access a communications network from different locations.  The US District Court for the Eastern District of Texas granted summary judgment that Cellco does not infringe claim 1 of the ‘706 patent.  Fenner appealed to the CAFC arguing that the district court erred in construing the term “personal identification number” in claim 1.  The CAFC affirmed the summary judgment of noninfringement.


At the time of the ‘706 patent filing, telephonic communications primarily consisted of switching units connected to a telephone present in a household or business.  When the telephone was used to make a call, the billing charges were associated with the telephone and not the individual making the call.

As discussed in the ‘706 patent, the personal communications services (PCS) concept was developed as a method for identifying telephone services independent of a telephone unit by assigning each telephone user a personal identification number.   The billing and call servicing are identified with the individual personal identification numbers and not with the telephone unit.

The ‘706 patent seeks to provide a PCS system that locates and tracks the personal identification numbers such that calls can be set up with and billed to the proper user.

Claim 1, the only asserted claim of the ’706 patent, is repeated below:

1.  A method of providing access to a mobile user in a communications system having a plurality of interconnected radio frequency communication switches for selectively collecting calls to mobile users via radio frequency links, a plurality of billing authorities for maintaining service profiles of mobile users and a plurality of location authorities for maintaining current locations of mobile users within the interconnected communication switches, the method comprising:

receiving at a radio frequency communication switch a personal identification number from a mobile user;

receiving from the mobile user at the communication switch a billing code identifying one of the plurality of billing authorities maintaining a service profile for the mobile use[r], wherein different ones of the plurality of billing authorities may maintain the service profile or a second profile for the mobile user identified by the personal identification number;

requesting a service profile of the mobile user from the billing authority identified by the received billing code;

storing in memory the service profile received from the billing authority; and

providing the mobile user access to the switch.

After a claim construction hearing, the district court adopted Verizon’s proposed construction of the term “personal identification number” in claim 1, construing it to mean “a number separate from a billing code (as construed herein) identifying an individual system user, which is associated with the individual and not the device.”  Based on the district court’s construction, the parties stipulated to final judgment of noninfringement subject to Fenner’s right to appeal.

Claim Construction

The issue on appeal is the district court’s construction of “personal identification number”.

On appeal to the CAFC, Fenner argued that the district court erred by narrowly construing “personal identification number” as a number that is associated with the individual user and not with the device.  Fenner’s position is that the plain meaning of “personal identification number” does not contain or require this limited definition, and that the district court erroneously imported this limitation from the specification and erroneously relied on the prosecution history to support this construction.

(I) Standard of Review         

In its claim construction analysis, the CAFC applies what appears to be a de novo standard of review.  The court’s analysis begins with:

“We review de novo the ultimate question of the proper construction of patent claims and the evidence intrinsic to the patent. Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 841 (2015); id. (‘[W]hen the district court reviews only evidence intrinsic to the patent (the patent claims and specifications, along with the patent’s prosecution history), the judge’s determination will amount solely to a determination of law, and the Court of Appeals will review that construction de novo.’). The district court’s determination of subsidiary facts based on extrinsic evidence is reviewed for clear error. Id. at 835, 841.”

(II) Claim Construction Analysis  

The Federal Circuit relied on intrinsic evidence found in the written description and prosecution history using the standard approach to claim construction that has been explained by the Federal Circuit in Phillips v. AWH Corp.  The opinion summarizes the claim construction process:

“The terms used in patent claims are not construed in the abstract, but in the context in which the term was presented and used by the patentee, as it would have been understood by a person of ordinary skill in the field of the invention on reading the patent documents. See Biogen Idec, Inc. v. GlaxoSmithKline LLC, 713 F.3d 1090, 1095 (Fed. Cir. 2013) (“[A] term’s ordinary meaning must be considered in the context of all the intrinsic evidence, including the claims, specification, and prosecution history.”). Thus, a claim receives the meaning it would have to persons in the field of the invention, when read and understood in light of the entire specification and prosecution history. Phillips v. AWH Corp., 415 F.3d 1303, 1312–1317 (Fed. Cir. 2005) (en banc). Any explanation, elaboration, or qualification presented by the inventor during patent examination is relevant, for the role of claim construction is to “capture the scope of the actual invention” that is disclosed, described, and patented. Retractable Techs., Inc. v. Becton, Dickinson & Co., 653 F.3d 1296, 1305 (Fed. Cir. 2011).”

(i) Written Description

To support the claim construction analysis, the Federal Circuit looked to drawing Fig. 1 (drawings are part of the written description) and the text of the ‘706 patent describing Fig. 1, which states “Referring now to Fig. 1, wherein there is shown a block diagram of the present invention. . . . The personal identification numbers 2 are not associated with any particular communications unit or physical location but are associated with individual users.” [Emphasis added.]

The Federal Circuit also looked to description in each of the Background of the Invention, the Summary of the Invention, and the Detailed Description sections of the ‘706 patent to support the construction that the personal identification number is associated with the user and not the device.  For example,

“Describing the PCS system as centered on the user instead of the device, the patent describes the ‘PCS concept envision[ing] each telephone user having a personal identification number’ and ‘[b]illing and call servicing are identified with the individual personal identification numbers and not with a telephone unit.’ Col. 1 ll. 24-30.”  [Emphasis added.]

“The patent states that its invention ‘overcomes’ these problems and accomplishes the tracking of location and billing authority through a user-centered system in which users have personal identification numbers that are associated with the individual user, but not a particular communications unit or physical location. Col. 1 l. 49; col. 2 ll. 35-37.”  [Emphasis added.]

(ii) Prosecution History

The Federal Circuit considered that the prosecution history bolstered the district court’s construction that the term “personal identification number” is a number associated with the user, not the device.

For example, in overcoming a rejection under §103, Fenner distinguished the claimed invention over US Patent No. 5,210,787 to Hayes by emphasizing that “[t]he present invention, on the other hand, is centered around the mobile user, not the mobile telephone. The user is identified by a personal code. Furthermore, the mobile user need not be, unlike a mobile telephone, assigned to a particular home exchange.”

Fenner argued that the purportedly limiting statements made during prosecution do not limit the claims because the statements and limitations discussed were not the basis for grant of the patent.  However, the Federal Circuit dismissed this argument noting that a patentee’s statements during prosecution, whether relied upon by the Examiner or not, are relevant to claim interpretation.

III. Fenner’s Additional Arguments

(i) Inoperability

Fenner argued that the district court’s claim construction of “personal identification number” to mean “associated with the individual and not the device” cannot be correct because it renders the patented invention inoperable.  Fenner asserts that only a device (not a person) is capable of transmitting the personal identification number to a radio-frequency communication switch, and that “a human being cannot communicate with such a switch except through a compatible radio-equipped cell phone or other wireless unit.”

However, the Federal Circuit dismissed this argument responding, “the district court’s construction requires only that a personal identification number is not permanently associated with a specific communications unit or location. This construction is not flawed.”

(ii) Claim Differentiation

Fenner also argued that the doctrine of claim differentiation negates the district courts claim construction because claim 19 would be redundant or superfluous if claim 18 is construed with the restriction imposed by the of the district court.

Claim 18 reads:

18.  In a communications network having a plurality of interconnected communication switches, and in which users are identified by a personal identification code wherever that user is located within the communications network, a method for completing a call from a source to a destination user comprising:

receiving from a source user logged onto a first communication switch a personal identification code of a destination user to whom a call is to be routed:

determining whether the destination user is currently logged onto the first communication switch; and

if the destination user is not logged onto the first communication switch,

identifying a location tracking authority assigned to the personal identification code of the destination user,

requesting from the location tracking authority an identity for a destination communication switch on which the destination user is currently logged onto,

receiving the identity of the destination communication switch at the first communication switch, and

routing the call to the destination switch.

Claim 19 states:

19.  The method of claim 18 wherein the personal identification number of the source and the destination user are independent of a particular physical communications unit.”

However, the Federal Circuit dismissed this argument responding, “[a]lthough claim differentiation is a useful analytic tool, it cannot enlarge the meaning of a claim beyond that which is supported by the patent documents, or relieve any claim of limitations imposed by the prosecution history.”


During claim construction, the claim language is not construed in the abstract.  The “plain meaning” of the claim language will be evaluated based on at least intrinsic evidence, such as the written description and the prosecution history.

During claim construction, the doctrine of claim differentiation does not trump the intrinsic evidence.

Full Opinion

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