PTAB

IPR2021-01423

Motorola Mobility LLC v. Evolved Wireless LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method for Performing Random Access Procedure
  • Brief Description: The ’679 patent discloses methods and systems for managing a random access procedure during the handover of a mobile terminal from a source base station to a target base station. The invention aims to reduce handover processing time by avoiding collisions on the Random Access Channel (RACH) through the use of a dedicated preamble provided to the terminal.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 and 6-8 are obvious over Nokia in view of Hu.

  • Prior Art Relied Upon: Nokia (3GPP draft R2-061135) and Hu (Chinese Application # CN159602A).
  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Nokia taught most elements of the challenged claims, disclosing a complete handover procedure in a Long Term Evolution (LTE) system. Nokia’s process involved a mobile terminal (UE) receiving a "Handover Command" with "necessary parameters," followed by synchronization with the target base station via a "Non contention based access burst" or a RACH procedure. Petitioner asserted that Nokia’s disclosure of a "non-contention" RACH procedure implies the use of a mechanism to avoid collisions on a shared channel.

      Petitioner contended that Hu supplied the specific implementation for this non-contention procedure. Hu taught a handover method where the target base station designates a specific "random access resource" (disclosed as an "uplink synchronization code," i.e., a preamble) for a particular mobile terminal. Hu specified that this resource is reserved for, dedicated to, and used only by that one terminal to enhance the access success rate, thereby teaching the use of a dedicated preamble for collision avoidance.

      The combination of Nokia and Hu allegedly disclosed all limitations of independent claims 1 and 6. For example, the "preamble information" of the claims was met by Hu's "random access resource." This information was received in Nokia's "Handover Command" (dedicated downlink signaling) and used for the RACH procedure. The UE then transmitted the dedicated preamble (per Hu) and received a "random access response" (Nokia's "UL allocation and timing advance"). Finally, the UE transmitted "uplink data" (Nokia's "Handover Confirm" message) using the uplink grant from the response. The dependent claims were allegedly met by further explicit teachings in the combined references.

    • Motivation to Combine (for §103 grounds): Petitioner argued a person of ordinary skill in the art (POSITA) would have been motivated to combine Nokia and Hu because both references address the same problem of improving handover efficiency in wireless communication systems. A POSITA implementing Nokia’s handover, which specified a "non-contention" RACH procedure over a shared channel, would have naturally looked to known techniques for collision avoidance. Hu provided a clear and advantageous solution by teaching the use of dedicated preambles for individual UEs during handover, a known method for managing shared channel resources.

    • Expectation of Success (for §103 grounds): A POSITA would have had a reasonable expectation of success in combining the references, as incorporating Hu’s dedicated preamble into Nokia’s "Handover Command" would have been a predictable implementation of a contention-free RACH procedure.

4. Key Claim Construction Positions

  • "handover": Petitioner argued this term is well understood and requires no construction. However, Petitioner preemptively argued against a potential construction from a prior litigation that would limit "handover" to a "hard" or "break-before-make" process. Petitioner asserted that the claims contain no such temporal limitations and that the specification does not disavow other handover types.
  • "target base station": Petitioner contended this term also needs no construction. It argued against a prior proposed construction limiting the term to "the base station to which the source base station determines the mobile terminal will be transferred." Petitioner argued this is improperly narrow, as various handover types do not require the source station to make the determination, and the intrinsic evidence does not support importing such a limitation.

5. Arguments Regarding Discretionary Denial

  • Petitioner presented extensive arguments that discretionary denial would be inappropriate under both 35 U.S.C. §314(a) (Fintiv factors) and §325(d).
  • Against Fintiv Denial (§314(a)): Petitioner noted that a parallel district court action was stayed. Regarding a parallel ITC proceeding, Petitioner stipulated that if the IPR were instituted, it would not assert any invalidity grounds based on Nokia in the ITC case, thereby eliminating any significant overlap between the forums. Petitioner also argued the merits of the petition were strong and that this petition was a "me-too" filing seeking joinder with a previously filed IPR, further weighing in favor of institution.
  • Against §325(d) Denial: Although Nokia and Hu were cited to the USPTO during prosecution, Petitioner argued they were part of a list of hundreds of references and were never substantively analyzed or applied by the Examiner in any rejection. Petitioner contended the Examiner materially erred by overlooking the clear teachings of the Nokia and Hu combination, which disclosed the use of a dedicated preamble for collision avoidance. This specific combination was not previously considered by the Office, and its arguments were not substantially the same as those presented in a prior IPR on a related patent.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3 and 6-8 of Patent RE46,679 as unpatentable.