Federal Circuit Affirms PTAB’s Non-Obviousness Decision Due To Lack Of Motivation To Combine
On April 13, 2021, the Court of Appeals for the Federal Circuit (CAFC) issued an opinion affirming the decision of the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB), finding that the claims of the challenged patent had not been proved obvious because the petition for inter partes review (IPR) failed to show that there would have been a motivation to combine the two allegedly invalidating prior art references. Apple Inc. v. INVT SPE LLC, —F.3d — (Fed. Cir. Apr. 13, 2021).
The challenged ’676 patent is directed to a radio communications system with a variable transmission rate, where decreasing the transmission rate is caused by increasing a spreading factor. The problem that the ’676 patent purports to solve relates to decreasing interference that results from an increase in transmission power, which power-increase compensates for low reception quality. To solve the interference problem, the ’676 patent discloses decreasing the transmission rate of the radio signal (by increasing the spreading factor), which allegedly improves reception quality without increasing interference with other mobile devices. According to the claims of the ’676 patent, the decrease of transmission rate is triggered only after determining that the “average transmission power” exceeds a predetermined threshold.
Petitioners-Appellants filed a petition for IPR alleging that the claims of the ’676 patent are obvious over a combination of two prior art references “Keskitalo” and “Lindell.” Keskitalo, a data throughput reference, discloses improving reception quality in a Code Division Multiple Access (CDMA) system by adjusting the spreading factor. Petitioners-Appellants conceded, however, that Keskitalo, while similar to the ’676 patent in some ways, does not disclose the “average transmission power” limitation. Petitioners-Appellants allege that one skilled in the art would have looked to a second reference, Lindell, to supply the missing “average transmission power” limitation. Lindell, a radiofrequency (RF) exposure reference, discloses a radio transmitter power controller that automatically restricts transmission power when the average power approaches or exceeds a predetermined limit. Lindell’s power controller, which uses an average-power-determining circuit to determine the average transmission power during a preceding time period (e.g., 6 or 30 minutes), is used to limit a user’s exposure to RF radiation (as transmission power and RF radiation are correlated). The PTAB found that a skilled artisan would not have been motivated to modify Keskitalo to measure average transmission power according to Lindell’s teachings, and therefore held that Petitioners-Appellants had failed to prove the challenged claims obvious.
On appeal, Petitioners-Appellants argued that the PTAB erred by misconstruing the proposed combination. Specifically, Petitioners-Appellants argued that the PTAB mistakenly viewed the obviousness argument as merging Keskitalo’s maximum possible power threshold with Lindell’s maximum permitted power threshold. To support their argument, Petitioners-Appellants quoted various excerpts of the PTAB’s final written decision that allegedly demonstrate the PTAB’s confusion. Petitioners-Appellants characterize their actual argument (which was allegedly not properly considered) as replacing Keskitalo’s instantaneous power measurement with an average power measurement (such as that disclosed in Lindell).
In finding that substantial evidence supported the PTAB’s decision, the CAFC explained that the quotes that allegedly supported Petitioners-Appellants’ view that the PTAB had misconstrued their argument were taken out of context, and that the full quotations demonstrated that the PTAB had in fact considered and rejected their argument. And, further, the CAFC agreed with the PTAB’s finding that there was no motivation to modify Keskitalo’s measurement of instantaneous transmission power to instead measure average transmission power. The CAFC found that, although Keskitalo and Lindell both involve measuring transmission power, they do so for different reasons, on different time scales, and compare the results to different thresholds. The CAFC explained that, on the one hand, Keskitalo compares transmission power to the maximum possible value to determine whether its system must resort to decreasing transmission rate to improve reception quality. On the other hand, Lindell compares average transmission power to the maximum permitted value to determine whether its system must decrease transmission power to limit RF exposure. The CAFC noted both that Petitioners-Appellants acknowledge these functionalities are “distinct,” and that Lindell operates on much longer time scales than Keskitalo, as Lindell discloses a relatively long averaging time (e.g., 6 or 30 minutes), as compared to Keskitalo’s relatively short-term power adjustments (i.e., every 1–1.25 milliseconds). The CAFC explained that, given these disparities, a reasonable fact finder could have concluded there was no motivation to combine Keskitalo and Lindell, and, therefore, that substantial evidence supports the PTAB’s decision.