Mentone Solutions LLC v. Digi International Inc.

Court of Appeals for the Federal Circuit·Decided November 15, 2021·No. 21-1202·Unpublished

Opinion

NOTE: This disposition is nonprecedential.

United States Court of Appeals for the Federal Circuit

MENTONE SOLUTIONS LLC,

Plaintiff-Appellant

v.

DIGI INTERNATIONAL INC.,

Defendant-Appellee

2021-1202

Appeal from the United States District Court for the District of Delaware in No. 1:20-cv-00280-LPS, Judge Leonard P. Stark.

-------------------------------------------------

MENTONE SOLUTIONS LLC,

Plaintiff-Appellant

v.

ELO TOUCH SOLUTIONS, INC., Defendant-Appellee

2021-1203

2 MENTONE SOLUTIONS LLC v. DIGI INTERNATIONAL INC.

Appeal from the United States District Court for the District of Delaware in No. 1:20-cv-00281-LPS, Judge Leonard P. Stark.

Decided: November 15, 2021

GEORGE PAZUNIAK, O'Kelly, Ernst, & Bielli, LLC, Wilmington , DE, for plaintiff-appellant.

AMR O. ALY, Jenner & Block LLP, New York, NY, for defendant-appellee Digi International Inc. Also represented by YUSUF ESAT, Chicago, IL; ADAM G. UNIKOWSKY, Washington, DC.

RICARDO BONILLA, Fish & Richardson P.C., Dallas, TX, for defendant-appellee Elo Touch Solutions, Inc. Also represented by NEIL J. MCNABNAY, MICHAEL VINCENT.

Before MOORE, Chief Judge, LOURIE and DYK, Circuit Judges.

MOORE, Chief Judge.

Mentone Solutions LLC appeals an order from the District of Delaware holding the claims of U.S. Patent No. 6,952,413 invalid under 35 U.S.C. § 101 and dismissing Mentone’s claim of patent infringement. For the following reasons, we reverse.

BACKGROUND

I

The ’413 patent relates to dynamic resource allocation in general packet radio systems. ’413 patent at 1:8–10. In those systems, a number of mobile stations communicate with a single network through physical links called Packet

MENTONE SOLUTIONS LLC v. DIGI INTERNATIONAL INC. 3

Data Channels (PDCHs). Id. at 1:13, 19–24. When the mobile stations receive information from the network, they are engaging in downlink (DL) communication, and when the mobile stations are transmitting information to the network, they are engaging in uplink (UL) communication. Id. at 1:28–32. These mobile stations communicate within time frames, each divided into eight timeslots. Id. at 1:24– 26. Figure 1 of the patent depicts the numbering convention used for uplink and downlink slots in two successive frames:

Each corresponding pair of slots (e.g., uplink slot 0 and downlink slot 0) represents a PDCH. Id. at 1:55–58.

To control access to the PDCHs, which are shared among mobile stations, the network uses an uplink status flag (USF). Id. at 1:50–54. That flag can take eight values, 0 through 7, allowing allocation of resources for up to eight mobile stations. Id. at 1:60–62. When a mobile station receives a USF, it may recognize the value as valid, which communicates exclusive use of resources to that station. Id. at 1:63–64. In systems using an extended dynamic allocation method, a mobile station’s reception of a valid USF in a certain downlink timeslot indicates the availability for that station to begin transmission in the corresponding uplink slot. Id. at 1:65–2:5.

To “utilize most effectively the available bandwidth,”

access to PDCHs may be dynamically allocated. Id. at 1:33–38. “The amounts of time that the mobile station receives downlink or transmits uplink may be varied and slots allocated accordingly.” Id. at 1:39–41. However, as explained below, at the time of the alleged invention, 4 MENTONE SOLUTIONS LLC v. DIGI INTERNATIONAL INC.

certain multislot patterns or configurations were not available due to restrictions in mobile stations.

II

The ’413 patent identifies two restrictions. First, “the mobile station is not able instantly to switch from a receive condition to a transmit condition or vice versa.” Id. at 2:11– 12. This turn-around time, along with the time needed to perform certain measurements, prevents certain multislot patterns from functioning. Id. at 4:1–8. Figure 3 depicts an example of an impermissible multislot pattern, specifically a steady state single-downlink and 5 uplink slot allocation for a class 34 mobile station:

Id. at 2:11–14; 4:5–7. Between uplink timeslot 4 of the first frame and downlink timeslot 0 of the second frame (shown as letter A), there is insufficient time for the mobile station to change from a transmit state to a receive state. Id. at 4:5–7.

Second, in systems using an extended dynamic allocation method, there is a fixed relationship between the downlink slot in which a valid USF is received and the uplink slot in which transmission begins; a mobile station’s receipt of a valid USF in a certain downlink timeslot indicates the availability for that station to begin transmission in the corresponding uplink slot. Id. at 1:65–2:5. For example , if a valid USF indicating the availability of four uplink slots is received at downlink timeslot 0, the mobile station begins transmission in the corresponding uplink timeslot 0. Id. at 2:1–10, 27–35. Figure 2 illustrates this fixed relationship:

MENTONE SOLUTIONS LLC v. DIGI INTERNATIONAL INC. 5

Id. at 3:61–67. Due to these two restrictions, certain multislot configurations were not possible.

III

The ’413 patent’s purported invention focuses on easing the latter restriction. It allows a mobile station access to previously restricted multislot configurations through “altering the fixed relationship in the timing of the downlink allocation signalling [sic] and subsequent uplink transmission for certain classes of mobile station.” Id. at 2:46–49. For example, it purports to allow configurations that would otherwise be impossible due to insufficient turnaround time. Compare id. at Fig. 3 with id. at Fig 4. The ’413 patent specification purports to alter this fixed relationship through shifting, to the second downlink slot, the USF indicating the mobile station may begin uplink transmission at the first uplink slot, as shown in Figure 4:

Id. at 4:8–19. Any USF corresponding to the second uplink slot is also placed in the second downlink slot. Id. at 4:12– 14. Through this shifted USF, the invention purports to “reduce restrictions affecting extended dynamic allocation with minimal effect on the existing prescript.” Id. at 2:44– 46. It allows the mobile station to “transmit up to its physical slot limit.” Id. at 5:17–18. The present invention increases the capacity of networks to communicate data by 6 MENTONE SOLUTIONS LLC v. DIGI INTERNATIONAL INC.

allowing the network to use timeslots for transmission which, according to the patent, were not available in the prior art. The result is a system capable of a higher rate of data transmission. Claim 5 is representative and recites:

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.

IV

Mentone sued Digi International Inc. and Elo Touch Solutions, Inc. (collectively Appellees) for infringement of at least claim 5 of the ’413 patent. Appellees moved to dismiss under Federal Rule of Civil Procedure 12(b)(6), arguing the ’413 patent claims are patent ineligible under 35 U.S.C. § 101. The district court held that claim 5, which the parties agreed is representative, is patent ineligible. The district court held claim 5 is “directed to the abstract idea of receiving a USF and transmitting data during the appropriate timeslots.” J.A. 7. It further held that the shifted uplink status flag combined with the “abstract idea,

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