Cradlepoint Inc v. Sisvel Intl SA

1. Case Identification

• Case #: IPR2020-01070
• Patent #: 7,433,698
• Filed: June 16, 2020
• Petitioner(s): Cradlepoint, Inc., Dell Inc., Sierra Wireless, Inc., Thales DIS AIS Deutschland GmbH, ZTE Corporation, and ZTE (USA) Inc.
• Patent Owner(s): Sisvel International S.A.
• Challenged Claims: 10, 11, 13, 17, and 24

2. Patent Overview

• Title: Cell Reselection Signalling Method
• Brief Description: The ’698 patent relates to a method for managing cellular network congestion. It discloses a mobile device receiving a connection rejection message that includes at least one frequency parameter, which directs the device to attempt a new connection on a different frequency, thereby improving cell reselection.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 10, 13, and 17 by Kallin

• Prior Art Relied Upon: Kallin (Patent 5,287,545).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kallin, which describes a 1G cellular system, anticipates all limitations of the challenged claims. When a mobile station attempts to access a congested cell, Kallin’s system sends a "directed retry message" (a connection rejection message) containing frequency parameters for neighboring cells. Kallin’s mobile station receives this message, observes the frequency parameters to identify candidate channels, selects the one with the strongest signal, and sets a parameter corresponding to that channel to initiate a new connection attempt. This process directly maps to the steps of receiving a rejection, observing a parameter, and setting a new parameter based on frequency information as recited in independent claim 10 and its dependents.

Ground 2: Obviousness of Claims 10, 11, 13, 17, and 24 over Ericsson Alone

• Prior Art Relied Upon: Ericsson (a 3GPP document labeled TSGR2#6(99)813).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Ericsson, a 3GPP working group paper proposing a specification for the Radio Resource Control (RRC) protocol, renders the claims obvious. Ericsson explicitly states that when any of a list of Information Elements (IEs) are received by User Equipment (UE) in any RRC message, the UE must perform specified actions. This list of messages includes the RRC CONNECTION REJECT message, and the list of IEs includes "Frequency info." Ericsson further teaches that if "Frequency info" is included, the UE must store it as the active frequency and tune to it. Petitioner argued this express teaching makes it obvious to include a frequency parameter in an RRC CONNECTION REJECT message to redirect the UE, thus teaching all limitations of the challenged claims.
  • Key Aspects: Petitioner contended that the Examiner and Patent Trial and Appeal Board (PTAB) erred during prosecution by concluding Ericsson was silent on sending a frequency parameter in a rejection message. This petition presented a new argument focusing on sections of Ericsson allegedly overlooked during prosecution.

Ground 3: Obviousness of Claims 10, 11, 13, 17, and 24 over TS 25.331 in view of Kallin or Kissee

• Prior Art Relied Upon: TS 25.331v.3.1.0 (a 3GPP technical specification), Kallin (Patent 5,287,545), and Kissee (Patent 6,567,665).

• Core Argument for this Ground:

  • Prior Art Mapping: The base reference, TS 25.331, is a 3G standard that defines the RRC CONNECTION REJECT message but does not explicitly include frequency information. The secondary references, Kallin (1G) and Kissee (2G), both teach using a rejection message (a "directed retry message") that includes frequency information to efficiently redirect a mobile device during network congestion.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these teachings because the 3G RRC CONNECTION REJECT message is a direct analog to the directed retry messages in the earlier 1G and 2G systems described by Kallin and Kissee. A POSITA would be motivated to incorporate the known and successful technique of frequency redirection from older systems into the 3G standard's rejection message to achieve more efficient connection, provide better network control, and improve user experience by reducing connection time and bandwidth usage.
  • Expectation of Success: A POSITA would have had a high expectation of success. The combination involves applying a well-understood technique (including frequency data in a rejection message) to a known protocol (3G RRC) to achieve the predictable result of improved connection re-establishment, a simple and functional improvement.

• Additional Grounds: Petitioner asserted additional challenges, including that claims 10, 13, and 17 are anticipated by Kissee; that claims 10, 13, and 17 are anticipated by C.S0005 (a cdma2000 standard); and that claims 10, 11, 13, 17, and 24 are obvious over TS 25.331 in view of C.S0005.

4. Key Claim Construction Positions

• "mobile communication means": Petitioner proposed this term from the preamble of claim 10 should be construed as "mobile station." This construction is consistent with the patent’s own specification and ensures the prior art, which describes mobile stations, maps directly to the claim language.
• "RRC CONNECTION REJECT message": Petitioner proposed this term from dependent claim 11 should be construed as the message defined in the 3GPP standard TS 25.331v.3.1.0. This was the version of the standard published at the time of the alleged invention and provides the technical foundation for several of the obviousness grounds.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that institution of the inter partes review (IPR) was proper and that the grounds were not cumulative of art considered during prosecution. It was argued that the core prior art references—Kallin, Kissee, C.S0005, and TS 25.331—were never applied or considered by the Examiner. For the Ericsson reference, which was considered, Petitioner argued that the Office erred in its analysis and that the new arguments and expert testimony presented Ericsson in a new light, pointing out specific teachings that were previously overlooked. These factors, Petitioner contended, weigh heavily in favor of institution.

6. Relief Requested

• Petitioner requested institution of an IPR and cancellation of claims 10, 11, 13, 17, and 24 of Patent 7,433,698 as unpatentable.