The Federal Circuit held almost twenty years ago, in 2007, that a signal (e.g., electrical or computer signal) is not subject matter eligible and, therefore, not patentable. In re Nuijten, 500 F.3d 1346 (Fed. Cir. 2007). This case remains good law and Examiners at the U.S.P.T.O. will cite this case in rejecting a patent application that appears to be claiming a signal as subject matter ineligible under 35 U.S.C.§ 101. Subject matter eligibility jurisprudence attempts to distinguish between patentable inventions and non-patentable abstract ideas, which the law holds that one person cannot exclude others from, as a matter of principle and practice. In re Nuijten's precedent is as close as anything gets to a bright line rule in the 35 U.S.C. § 101 subject matter eligibility jurisprudence—a signal cannot be patented. However, with a simple grammatical change "signal" becomes the verb, "signaling," and In re Nuijten ceases to proscribe patenting.
Method claims are used in patent applications to cover the steps of a process. Processes are subject matter eligible. Generally, each clause of a method claim, which defines the scope of the process being patented, begins with a verb in its present participle verb form (e.g., heating, controlling, signaling, etc.)
In In re Nuijten, the court stated that "transitory embodiments [like signals] are not directed to statutory subject matter" and found Claim 14 of the Nuijten patent directed to ineligible subject matter (reciting a transitory signal). Id. Ineligible Claim 14 is quoted below:
A signal with embedded supplemental data, the signal being encoded in accordance with a given encoding process and selected samples of the signal representing the supplemental data, and at least one of the samples preceding the selected samples is different from the sample corresponding to the given encoding process.
While holding that transitory embodiments are non-subject matter eligible, the In re Nuijten court further opined that subject matter eligible processes (method claims) require action. Id. However, actions are transitory by nature. Accordingly, a transitory signal can be claimed as an action with a change in grammatical form. Below Nuijten, Claim 14 is redrafted with the noun "signal" in a verbal (present participle) form, "signaling," denoting action, without changing the scope of the claim. (One could also add the phrase "using a physical carrier" to include some non-abstract claim elements and further avoid a 35 U.S.C. § 101 rejection.)
A process of signaling supplemental data, including:
signaling[, using a physical carrier,] in accordance with a given encoding process;
signaling[, using the physical carrier,] with selected samples representing supplemental data; and
signaling[, using the physical carrier,] with at least one sample preceding the selected samples differently than the sample corresponding to the given encoding process.
There is no logical difference between the above claim and Nuitjen's ineligible Claim 14; the difference is grammatical.1 For example, a network carrier that conveys the watermarked signal will necessarily be performing the above process. Nuitjen made the argument that his signal was a process, however the court rejected the argument because "his claims . . . do not recite acts." Id.
By changing a noun to a verb in present participle form, a thing becomes an act, and a signal becomes patent eligible subject matter.
Footnote
1. While I contend there is no logical difference, the law does treat system claims and method claims different. For instance, an infringer needs to practice each and every step of a method claim, but only needs to implement and benefit from the implementation of a system (other parties can do some of the system steps).
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