In Cox Communications, Inc. v. Sprint Communication Co. LP, No. 2016-1013 (Fed. Cir. Sept. 23, 2016), the Federal Circuit reversed the district court’s determination that certain claims were indefinite under 35 U.S.C. § 112 ¶ 2 due to the phrase “processing system.” Id. at 3. The majority did so in a rather unique way, i.e., by considering how the claims would be affected if the alleged indefinite phrase “processing system” were omitted from the claim and concluding that doing so would not change the scope of the claims. Slip op. at 9-12. According to the majority, because the “point of novelty resides with the steps of the method claims, not with the machine that performs them,” they could be “revised to remove the word ‘processing system,’” without “discernably chang[ing]” their meaning. Id. at 9. The majority continued: “If ‘processing system’ does not discernably alter the scope of the claims, it is difficult to see how this term would prevent the claims … from serving their notice function under § 112, ¶ 2.” Id. at 12.
Judge Newman concurred in the result, i.e., that the claims were not invalid due to indefiniteness, but she took issue with the way the majority reached that result:
I agree with the court’s holding that the claims are not invalid on the ground of indefiniteness. However, the court creates an interesting, but flawed, new mode of analysis, whereby the adjudicator (1) first removes the challenged term from the claim, then (2) decides whether the claim has the same meaning without the challenged term, and (3) if the answer is “yes,” rules that the claim is not indefinite as a matter of law. Maj. Op. at 10–12. This new style of claim construction will confound the already confused determination of patent rights. I write to protest this further inroad on a reasoned and reliable law of patents. [Slip op. at 2 (Newman, J., concurring opinion).]
Cox Communications is an appeal from a district court rather than from the PTAB. While the PTAB generally follows Federal Circuit case law in deciding issues before it, the PTAB’s standard for indefiniteness contains some subtle differences than the standard used in district court. As set forth in Ex parte Miyazaki, 89 U.S.P.Q.2d (BNA) 1207, 1211 (BPAI Nov. 19, 2008) (precedential), “if a claim is amenable to two or more plausible claim constructions, the USPTO is justified in requiring the applicant to more precisely define the metes and bounds of the claimed invention by holding the claim unpatentable under 35 U.S.C. § 112, second paragraph, as indefinite.” That being said, it appears that the reasoning of the Cox Communication decision may apply with equal force to the indefiniteness standard used by the PTAB.  As in Cox Communication, if the disputed term has no effect on the overall scope of the claims, presumably the claim is not amenable to two or more constructions based on that term and thus would pass muster with respect to Miyazaki.
Going forward, it will be interesting to see whether parties try to utilize the Cox Communications decision’s approach to argue against indefiniteness. The same logic would seem to apply in PTAB proceedings and would provide one means for countering any assertion of indefiniteness. It will also be interesting to see how the PTAB reconciles the decision with its own Miyazaki precedential decision regarding indefiniteness and whether Judge Newman’s concern come to pass. That is, to the extent the Federal Circuit has confused the law on indefiniteness in Cox Communications, in attempting to apply the Federal Circuit’s analysis to post-grant review proceedings, will the PTAB’s law on indefiniteness also become confused? We will have to stay tuned.
 Inter partes reviews, technically, are limited to prior art issues, i.e., ones to be decided under 35 U.S.C. § 102 or 103. Nevertheless, the PTAB has addressed indefiniteness issues in inter partes reviews. See, e.g., Activision Blizzard, Inc. v. Acceleration Bay, Inc., IPR2016-00724, Paper 11 at 9 (Sept. 7, 2016) (refusing to institute with respect to claim 9 because PTAB determined the claim was indefinite). See Dahlgren & Linck, “Claim Survives IPR Challenge Due to Indefiniteness,” www.ptablaw.com (Sept. 12, 2016). The issue may also arise during the course of claim amendments.