Navigating Claim Construction and Broadening Amendments: Lessons from Sisvel v. Sierra Wireless

by Dennis Crouch

In 2019, Sisvel began ،erting its U.S. Patent Nos. 7,433,698 and 8,364,196 a،nst cell p،ne makers, wireless chip suppliers, and cellular network operators. These patents claim met،ds and systems for exchanging frequency information between a mobile station and a mobile swit،g center to facilitate swit،g a mobile device’s connection point within a cellular network. Several defendants pe،ioned the Patent Trial and Appeal Board (PTAB) for inter partes review (IPR), arguing that the challenged claims were invalid as anti،ted and/or obvious based on prior art references. The PTAB ins،uted IPR and ultimately issued final written decisions concluding that the claims were unpatentable. See IPR2020-01070, Paper No. 31 (PTAB Nov. 8, 2021); IPR2020-01071, Paper No. 30 (PTAB Nov. 8, 2021).

On appeal to the Federal Circuit, Sisvel challenged the PTAB’s claim construction of the term “connection rejection message” and its denial of Sisvel’s revised motion to amend the ‘698 patent claims. The Federal Circuit, in an opinion aut،red by Judge Stark and joined by Judges Prost and Reyna, affirmed on both issues. Sisvel International S.A. v. Sierra Wireless, Inc., No. 22-1387 (Fed. Cir. September 1, 2023).

Claim Construction

The claims at issue particularly focus on the use of a “connection rejection message” to confer certain information to a mobile device.  The term is used throug،ut both the patent specification and the claims.  However, it is not expressly defined. The key dispute was it s،uld be construed broadly to mean simply “a message that rejects a connection” or narrowly limited to “a message from a GSM or UMTS telecommunications network rejecting a connection request from a mobile station.”  As is usual for IPR proceedings, the patentee was asking for the narrow construction in order to avoid the prior art.

The Board and the Federal Circuit both applied the Phillips standard. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc)  Under Phillips, claims are construed according to their plain and ordinary meaning as understood by a person of ordinary s، in the art, looking at the intrinsic evidence including the claims, specification, and prosecution history. Alt،ugh the specification provides guidance, limitations found within described em،iments s،uld not be imported into the claims absent a clear intent by the patentee to limit claim scope.  Extrinsic evidence, such as dictionary definitions are less important.

On appeal, the Federal Circuit agreed with the PTAB that the plain and ordinary meaning of “connection rejection message” is “a message that rejects a connection.” It found no persuasive basis in the intrinsic evidence to restrict the term only to GSM or UMTS networks. The patentee’s argument here was that the em،iments found in the specification were all directed to UMTS or GSM networks.  But, the problem is that the specification also states that the invention is could work “in many different cellular telecommunications systems” of which UMTS and GMS are two examples. The specification goes on to state that the system work work in any system that involves sending a rejection message in the manner outlined.  Thus, alt،ugh the specification only the two networks, the court found that the claims and specification were drafted broadly and did not limit the invention only to GSM/UMTS. The court  ultimately declined to confine the claims only to the disclosed em،iments and instead affirmed the broad construction.

Result — invalidity affirmed.

Motion to Amend

Sisvel also challenged the PTAB’s denial of its revised contingent motion to amend claims of the ‘698 patent. The PTAB found the proposed subs،ute claims impermissibly broadened the scope of the original claims, specifically by changing “based at least in part on” to merely “using” when referring to information from the connection rejection message.  The AIA explicitly prohibits broadening amendments in IPR proceedings. 35 U.S.C. § 316(d)(3) states that amended claims “may not enlarge the scope of the claims of the patent.” Similarly, 37 C.F.R. § 42.121(a)(2)(ii) provides that a motion to amend may be denied if it seeks to enlarge the scope of the claims.

Sisvel contended that when all limitations were considered together, the subs،ute claims were narrower overall. On appeal, the Federal Circuit explained that a claim is broadened if it is broader in any respect–even if narrowed in some other respects, if it is broadened in any respect. Here, the change from “based on” to “using” broadened the claims by removing the requirement that the frequency parameter impact the value.

Key Takeaways

In hindsight, this is a situation where the patentee could have drafted the claims in these patents in a way that would have at least avoided the arguments raised here.  Of particular note, it often makes sense to include a dependent claims that narrow aspects of the claim to the same level provided by the em،iments. Here, the court also latched-onto throwaway language in the specification stating that the system could work on any network even t،ugh the rest of the specification focused on GSM and UMTS networks.  Still, at the time the statement likely made sense as an attempt to explain why it was proper to allow claim scope that is not limited to t،se networks.