PTAB

IPR2017-00696

T-Mobile US Inc v. Huawei Technologies Co Ltd

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Device for Realizing IP Multimedia Subsystem Disaster Tolerance
  • Brief Description: The ’365 patent describes methods for providing disaster tolerance in an IP Multimedia Subsystem (IMS) network. The technology focuses on recovering a user's service when a critical server, the Serving Call Session Control Function (S-CSCF), fails or restarts by backing up necessary user data to a Home Subscriber Server (HSS) and restoring it to a new or restarted S-CSCF.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claims 1 and 3 over Phan-Anh and S2-060216

  • Prior Art Relied Upon: Phan-Anh (Patent 7,769,374) and S2-060216 (a 3GPP technical contribution document from Jan. 2006).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Phan-Anh taught the core concept of the ’365 patent: applying a well-known checkpointing recovery technique to an IMS network. Specifically, Phan-Anh disclosed storing "necessary data," such as a user's Transport Address (TA), on the HSS during registration and retrieving that data to restore service after an S-CSCF fails and restarts. Petitioner asserted that S2-060216 supplied the remaining key limitation: a procedure for assigning a new S-CSCF when the originally assigned S-CSCF becomes unavailable during a call setup.
    • Motivation to Combine: A POSITA would combine these references to create a comprehensive disaster recovery solution. Phan-Anh provided a solution for an S-CSCF restart, while S2-060216 provided a solution for S-CSCF failure requiring re-assignment. Both addressed the same technical problem in the same context (mobile call termination). A POSITA would have found it a simple matter to incorporate the specific re-assignment messaging (e.g., LIR/LIA messages) detailed in S2-060216 into the recovery framework taught by Phan-Anh.
    • Expectation of Success: A POSITA would have a high expectation of success because the combination involved applying a known procedure (re-assignment from S2-060216) to a known system (the recovery framework of Phan-Anh) to achieve a predictable result.

Ground 2: Anticipation of Claim 27 by Vergara

  • Prior Art Relied Upon: Vergara (Patent 8,438,257).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner first contended that claim 27 of the ’365 patent was not entitled to its earliest claimed priority date (Oct. 24, 2006) because the subject matter of the claim was absent from the corresponding priority application. This would make Vergara, filed in 2007, valid prior art under 35 U.S.C. §102(e). Petitioner argued that Vergara taught every limitation of claim 27. Vergara disclosed an identical IMS recovery procedure for when an S-CSCF restarts and loses its locally stored user data. This included backing up "contact data" (including P-CSCF address and user equipment address) to the HSS during registration, and upon detecting a restart, having the S-CSCF query the HSS to retrieve the backed-up data and subscriber profile to restore service.
    • Key Aspects: The argument hinged on successfully invalidating the priority claim for claim 27, which was directed specifically to a restart scenario that Petitioner alleged was only added in a later priority document.

  • Additional Grounds: Petitioner asserted additional challenges, including that claims 1 and 3 are obvious over Phan-Anh, S2-060216, and 3GPP TS 23.228 to address potential narrow claim constructions. Petitioner also asserted that claim 27 is anticipated by Phan-Anh, and that claims 1 and 3 are obvious over Phan-Anh in view of TR 23.821, S2-060216, and TS 23.228.

4. Key Claim Construction Positions

  • Petitioner argued that the terms "necessary data which is required when a user service processing is restored," "necessary data," and "backup necessary data" should be given their ordinary and customary meanings.
  • This position was presented to counter an anticipated narrower construction from the Patent Owner, which sought to require specific data elements like a SIP URL of a P-CSCF and a user device contact address. Petitioner contended that even under this narrower construction, the prior art taught these limitations, as a POSITA would have understood that such addresses were essential for service restoration and would have obviously stored them in the HSS.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 3, and 27 of the ’365 patent as unpatentable.