When undertaking a patent infringement analysis, a patent owner’s first task is to construe the claims. When technology continues its march forward, the evolving state of the art can present opportunities for wider adoption of earlier-patented inventions, but can also foreclose patent enforcement if the specification does not leave room for technological alternatives. Such was the case in the Federal Circuit decision in Ruckus Wireless, Inc. v. Innovative Wireless Solutions, LLC, Nos. 2015-1425, -1438 (Fed. Cir. May 31, 2016). This case provides a useful reminder to patent practitioners that when drafting specifications, providing a range of exemplary alternatives can be an important consideration.

The case involved Innovative Wireless Solution’s U.S. Patent Nos. 5,912,895; 6,327,264; and 6,587,473 (collectively, “the Terry patents”), claiming a collision avoidance scheme for data communicated in a local area network (LAN) where there is a relatively large distance between master and slave modems. In their simplest form, the Terry patents claim managing data traffic over a “communications path” connecting two modems. Slip op. at 3-4.

The claimed “communications path” was held by the trial court to require wired communication, and thus found Ruckus’s use of wireless communications to be noninfringing. On appeal, the Federal Circuit took this outcome-determinative issue of claim construction de novo, noting that the trial court had used exclusively intrinsic evidence from the file wrapper.

The Federal Circuit affirmed the Western District of Texas in a 2-1 decision, with a dissent filed by Judge Leonard P. Stark, Chief District Judge from the District of Delaware, who sat by designation.1 Consistent with the trial court’s findings, the Federal Circuit found that the Terry patents made no mention of wireless communication. In discussing the trial court’s decision, the Federal Circuit stated:

The district court found particularly persuasive a passage from the written description regarding the scope of alternative embodiments. That passage states that, “although as described here the line 12 is a telephone subscriber line, it can be appreciated that the same arrangement of master and slave modems operating in accordance with the new protocol can be used to communicate Ethernet frames via any twisted pair wiring which is too long to permit conventional 10BASE-T or similar LAN interconnections.”

(citation omitted). The Federal Circuit found that the repeated discussions of wired communications exclusively, and the disclosure’s solution to a problem belonging to long-distance communications over wires, was an important consideration. Id. at 7. The appeals court also explained that the patentee’s assumption that the term “communications path” had an ordinary meaning that encompassed both wired and wireless communications was not supported by the intrinsic or extrinsic record. Id. The majority further found that the intrinsic record “militate[d] powerfully” against patentee’s argument in several important ways, in addition to the absence of any discussion of wireless embodiments. Id. at 7-8.

First, the shared title of the Terry patents is “Information Network Access Apparatus and Methods for Communicating Information Packets Via Telephone Lines.” Second, the specification describes “[t]his invention” as one “particularly concerned” with “two-wire lines such as telephone subscriber lines.” See ’895 patent, col. 1 ll. 6–10. Third, every embodiment described in the specification utilizes a telephone wire, and every statement expressing the full breadth of the invention refers only to other wired connections. Id. at col. 9 ll. 45–51.

The insights of Plas-Pak—and the line of cases cited in the opinion—might be useful in attacking rejections where obviousness rejections violate a prior art reference’s “principle of operation” or “intended purpose.” Because these attributes are questions of fact, applicants should build a record that will support an advantageous position, which could include using declarations in appropriate circumstances.

The majority also analyzed the claims as a whole, but found no support for the patentee’s argument that “communications path” includes wireless communications. The dependent claims, to the extent that they characterized the “communications path,” referred to a “two-wire telephone subscriber line” (’895 patent, claims 13, 21, 23, 25) or a “two-wire line” (’473 patent, claims 6, 21, 27, 28). Each variation is a form of wired communication, and although the court acknowledged that the doctrine of claim differentiation can broaden a claim element’s meaning, it cannot extend it outside the boundaries of what would be understood by one of ordinary skill in the art. Ruckus Wireless, slip op. at 8-9.

The Federal Circuit concludes its analysis by pointing out that, in litigation, an ambiguous claim should be construed to preserve its validity. Here, to construe the claims to include wireless communications would implicate their validity as lacking written description. So, even if the extrinsic evidence were to show that one of skill in the art would understand the term “communications path” to include wireless communications, one could speculate that the claims might nevertheless fail the test for written description.

Patent prosecutors should try to accommodate alternatives to claim elements in the specification. While there are no crystal balls, emerging technical alternatives are sometimes possible to identify. As shown in this case, even when claims are broad, if the specification is not written to accommodate alternatives, it can limit the claims, especially where vague claim terms correspond to relatively narrow disclosure. Practitioners should avoid giving narrow examples without a more general description of the elements forming the exemplary embodiment. Also, beware of titles and how the word “invention” is used in the specification. Ordinary words may be limiting!