PTAB

IPR2021-01092

Ericsson Inc v. TOT Power Control SL

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Outer loop power control method and device for wireless communications systems
  • Brief Description: The ’865 patent discloses a method for managing outer loop power control in wireless communication systems, such as WCDMA. The technology addresses the "wind-up" problem, where a device's transmission power excessively increases during poor channel conditions and remains too high after conditions improve, causing unnecessary interference. The patent’s claimed invention is a method to rapidly reduce the signal-to-interference ratio (SIR) target back to its pre-wind-up value at the start of the "unwinding" phase.

3. Grounds for Unpatentability

Ground 1: Claims 1-12 are obvious over Chi in view of Murata.

  • Prior Art Relied Upon: Chi (Application # 2003/0148769) and Murata (Application # 2004/0259584).
  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Chi, a reference cited during prosecution, discloses most elements of the challenged claims. Chi teaches a CDMA outer loop power control system that detects a "wind-up" condition (e.g., when the measured SIR fails to track the target SIR due to an obstruction) and caps the target SIR to prevent it from growing excessively. Chi also discloses detecting the start of an "unwinding" process when channel conditions improve. However, Petitioner contended that the examiner allowed the claims because Chi did not explicitly teach modifying the target SIR at the start of unwinding to match the level it was at just before wind-up began.

      Petitioner asserted that Murata supplies this missing teaching. Murata addresses the same problem of excessive power consumption after a mobile device emerges from a poor propagation environment (e.g., "shadowing"). Murata explicitly teaches that upon detecting departure from the shadowing state (the start of unwinding), its system "shifts the state to the initial state again and lowers the SIR rapidly down to the SIR convergence point." Murata’s figures illustrate the actual target SIR being "instantaneously" lowered to the ideal target SIR level from just prior to the wind-up event. This, Petitioner argued, directly teaches the final limitation of independent claims 1 and 5. Arguments for dependent claims 2-4 and 6-12 followed from the teachings of Chi and the combination with Murata.

    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Chi and Murata because both references address the identical problem of excessive transmission power during the unwinding phase of outer loop power control. Chi provides a robust framework for detecting and managing wind-up but is less specific on the optimal unwinding procedure. Murata provides a specific, advantageous solution for unwinding by rapidly returning the target SIR to its pre-wind-up state. A POSITA would have been motivated to implement Murata's explicit and rapid unwinding technique into Chi's system to achieve the shared goals of reducing interference, improving system capacity, and conserving power, as taught by both references.

    • Expectation of Success: A POSITA would have had a high expectation of success. The combination involved integrating known control logic from Murata into the well-defined system of Chi, likely as a software modification. Both references operate in the same technical field (WCDMA power control) and their principles are fully compatible, ensuring a predictable and successful outcome.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under 35 U.S.C. §325(d). Although Chi was before the examiner, the combination with Murata was not. Petitioner asserted that Murata expressly teaches the very limitation added by the Patent Owner to overcome the examiner’s rejection over Chi. Therefore, the argument and art combination are not substantially the same as those before the examiner, and the examiner materially erred by not considering a reference like Murata.
  • Petitioner also argued against discretionary denial under 35 U.S.C. §314(a) and the Fintiv factors. Petitioner stated it would stipulate not to pursue in the parallel district court litigation any ground raised or that could have been reasonably raised in the IPR. Furthermore, the parallel litigation was in a very early stage, with no trial date set and minimal investment by the parties or the court. Petitioner argued these factors weigh strongly in favor of institution, as the IPR would be a true alternative to litigation and would serve the interests of efficiency and fairness.

5. Relief Requested

  • Petitioner requests institution of an inter partes review of claims 1-12 of the ’865 patent and cancellation of those claims as unpatentable.