In Mentone Solutions LLC v. Digi International Inc., 2021 WL 5291802 (Fed. Cir. Nov. 15, 2021) the U.S. Court of Appeals for the Federal Circuit reversed the U.S. District Court for the District of Delaware and former Chief Judge Leonard Stark, who had found U.S. Patent No. 6,952,413 invalid under 35 U.S.C. §101. (Stark was confirmed earlier this month to fill the upcoming Federal Circuit vacancy created by the scheduled retirement of Judge Kathleen O'Malley in March 2022.)

The patent allows mobile communication base stations to use previously unavailable time slots in a communication transmission protocol. This resulted in increased data communication capacity of a network. More particularly, the patent disclosed a technique of shifting previously fixed uplink status flags (USFs). The shifting allowed base stations to respond to transmissions without the prior impediment of waiting to send data as required by the traditional, fixed USFs.

Representative claim 5 reflects the technical details that achieve increased network capacity:

5. A multiple access communication method in a mobile station, comprising the steps of:

receiving an assignment of at least a first PDCH (packet data channel) and a second PDCH;

monitoring an assigned PDCH to detect a USF; and

transmitting on an assigned PDCH corresponding to the USF,

wherein (i) if shifted USF operation is not used then a first assigned PDCH is monitored to detect a USF corresponding to the first assigned PDCH and (ii) if the shifted USF operation is used then a second assigned PDCH is monitored to detect the USF corresponding to the first assigned PDCH and a USF corresponding to the second assigned PDCH.

The district held that claim 5 was directed to the abstract idea of "receiving a USF and transmitting data during the appropriate time slots." The Federal Circuit found that characterization a too high-level description of the use of USFs, which best described the prior art. The characterization did not reflect the invention recited by the claims, and specifically the characterization failed to mention the technological improvement, that is, the USF shifting recited by the claims.

In so concluding, the Federal Circuit looked to the specification to identify the problem solved, and to ascertain the details of how the problem was solved. The patent specification, according to the Federal Circuit, disclosed how shifting of the USFs resulted in improved network capacity.

With that understanding of what the patent was directed to, and how the goal of increased data capacity was achieved, the Federal Circuit looked at the claims to determine if they recited how and why the status flags, USFs, would be shifted. The Federal Circuit specifically determined that the claims identified details on how the results of improved data capacity were achieved, the recited USF shifting. The Federal Circuit thus found that claim 5 did not merely recite a desired goal, improved data capacity. It instead recited a particular method of breaking the prior fixed location of the USF status flag, which breaking resulted in the desired improvement of increasing data capacity. Finding that the claims recited details of how to achieve increased data capacity, the Federal Circuit held the claims patent eligible.

Finally, because the Federal Circuit found the claims directed to a technical improvement in network data capacity under Alice Corp. v. CLS Bank Int'l, 573 U.S. 208, 216 (2014) step one, the Federal Circuit did not reach Alice step two.

* * *

Thank you for reading.