Important to keep claim construction in mind when drafting a patent applicationSeptember 25, 2023

Claim construction, or how claim terms of a patent are understood, interpreted, and construed, is often a major factor in the outcome of a patent infringement lawsuit. Claim construction also can often be a highly contentious point of disagreement amongst parties in an infringement suit. The meaning of claim terms can often dictate the scope of the claims of a patent, which directly impacts potential infringement situations. While claim construction involves an analysis that can include many different factors and which is not fully discussed herein, as a patent applicant/owner, it is important to remember that the specification of the patent application or patent has a significant impact on claim construction.

We are reminded of the importance of a patent application’s or patent’s specification in terms of claim construction in a recent decision from the Court of Appeals for the Federal Circuit (“Federal Circuit”). On September 1, 2023, in Sisvel International S.A. v. Sierra Wireless, Inc., et al., (“Sisvel v. Sierra”) the Federal Circuit opined on an issue of claim construction.

Sisvel v. Sierra involved an appeal by Sisvel International S.A. (“Sisvel”) of two inter partes review decisions wherein the Patent Trial and Appeal Board (“PTAB”) held claims of two patents owned by Sisvel to be unpatentable as anticipated and/or obvious. The two patents at issue were U.S. Patent No. 7,433,698 (“the ‘698 patent”) and U.S. Patent No. 8,364,196 (“the ‘196 patent”), wherein the ‘196 patent is a continuation of the patent application that resulted in the ‘698 patent. The ‘698 and ‘196 patents “claim methods and apparatuses that rely on the exchange of frequency information in connection with cell reselection between a mobile station (or user cell phone) and a central mobile switching center.” In the claims at issue, both the ‘698 and ‘196 patents include the claim term “connection rejection message.” The Federal Circuit notes that the ‘698 patent employs “a connection setup rejection message . . . to direct a mobile communication means to attempt a new connection with certain parameter values such as a certain carrier frequency.” Further, the court notes that the ‘698 patent describes that the connection rejection message is “used to direct a mobile communication means to attempt a new connection with certain parameter values such as a certain carrier frequency.” The portion of Sisvel’s appeal related to claim construction focuses solely on construction of the term “connection rejection message”.

On appeal, Sisvel argued that the PTAB erred in its construction of the term “connection rejection message.” In its decision, the Federal Circuit noted that in claim construction, “[t]he words of a claim are generally given their ordinary and customary meaning as understood by a person of ordinary skill in the art when read in the context of the specification and prosecution history.” Thorner v. Sony Comput. Ent. Am. LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012) (citing Phillips v. AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc)). The Federal Circuit further noted that a “claim term’s plain and ordinary meaning will not apply 1) when a patentee sets out a definition and acts as his own lexicographer, or 2) when the patentee disavows the full scope of a claim term either in the specification or during prosecution.’” Thorner, 669 F.3d at 1365. Thus, it is important that a patent applicant understands that the specification, as well as prosecution history, of the patent application impacts claim construction.

The Federal Circuit agreed with the PTAB that the claim term “connection rejection message” should be given its plain and ordinary meaning of “a message that rejects a connection.” Sisvel argued that the term at issue should be given the meaning of “a message from a GSM or UMTS telecommunications network rejecting a connection request from a mobile station.” However, the Federal Circuit found that Sisvel’s proposed construction would “improperly limit the claims to embodiments using a Global System for Mobile Communication (“GSM”) or Universal Mobile Telecommunications System (“UMTS”) network.”

The Federal Circuit found no basis to limit the claim to any particular cellular networks. The claim language itself broadly claims use of a cellular telecommunication network. Further, while the specifications only explicitly describe embodiments in a UMTS or GSM network, the specifications also include:

[t]he invention is applicable in many different cellular telecommunication systems, such as the UMTS system or the GSM system. The invention is applicable in any such cellular telecommunication system, in which the cellular telecommunication network sends a rejection message as a response to a connection setup request from a mobile station, if the network is unable to provide the requested connection.

Thus, the Federal Circuit agreed with the PTAB in that the claim term at issue can refer broadly to telecommunication systems other than only UMTS or GSM systems. Therefore, the Federal Circuit affirmed the decision of the PTAB that the claims at issue are unpatentable in light of the prior art. While Sisvel raised another argument in its appeal regarding amendment of the claims, that portion of the appeal is not discussed herein.

Sisvel v. Sierra is a reminder to patent applicants that wording of the specification has a significant impact on construction of claim terms. Thus, it is important to draft claims in the context of the specification.

Joseph M. Hallman is a Patent Attorney in the Mechanical and Electrical Patent Practice Groups at McKee, Voorhees & Sease, PLC. For additional information please visit or contact Joseph directly via email at

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