PTAB

IPR2018-01773

Sprint Spectrum L.P. v. Intellectual Ventures II LLC

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1. Case Identification

2. Patent Overview

  • Title: Combined Open and Closed Loop Power Control
  • Brief Description: The ’828 patent discloses a system for managing the uplink transmit power of a user equipment (UE) in a wireless network. The technology purports to improve upon conventional power control by strategically combining aspects of both open-loop (path loss-based) and closed-loop (TPC command-based) schemes to achieve fast and accurate power adjustments.

3. Grounds for Unpatentability

Ground 1: Obviousness over Zeira, Krishnan, and Khan - Claims 1-2, 5-6, 8-9, 12-13, 15-16, 19-20, 22-23, 26-27, 29-30, 33-34, 36-37, and 40-41 are obvious over Zeira in view of Krishnan and Khan.

  • Prior Art Relied Upon: Zeira (Patent 6,600,772), Krishnan (Patent 7,493,133), and Khan (Application # 2004/0190485).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the primary reference, Zeira, discloses the core of the claimed invention: a combined open-loop/closed-loop power control system where a UE determines path loss and calculates transmit power based on both path loss and accumulated Transmit Power Control (TPC) commands. However, Zeira does not explicitly teach certain implementation details. Krishnan was asserted to supply the teaching of using a specific feedback signal (an “enable/disable bit”) to indicate whether closed-loop power control, and thus the accumulation of TPC commands, is enabled. Khan was argued to teach the final key element: transmitting both an allocation of a scheduled uplink resource (a scheduling grant) and TPC commands together on a single physical channel (a Walsh channel) to improve efficiency.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to achieve predictable improvements. Zeira’s disclosure that a network may wish to use solely open-loop or closed-loop control would motivate a POSITA to implement Krishnan’s explicit enable/disable signal. Similarly, Zeira’s reference to “assigned resource units” without specifying the assignment mechanism would lead a POSITA to Khan’s efficient method for allocating uplink resources and transmitting that allocation information alongside TPC commands on a single physical channel.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves applying prior art elements according to their established functions to achieve their known benefits—namely, switchable power control modes and efficient use of channel resources.

Ground 2: Obviousness over Zeira, Krishnan, Khan, and Andersson - Claims 2, 9, 16, 23, 30, and 37 are obvious over the combination of Zeira, Krishnan, Khan, and Andersson.

  • Prior Art Relied Upon: Zeira (Patent 6,600,772), Krishnan (Patent 7,493,133), Khan (Application # 2004/0190485), and Andersson (Patent 6,334,047).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targets dependent claims requiring a “multilevel TPC command.” The argument builds on Ground 1, adding Andersson to explicitly teach this limitation. Petitioner argued that while Zeira’s teaching that TPC step sizes are “typically 1 dB although other values may be used” renders the limitation obvious, Andersson provides a more explicit disclosure. Andersson teaches an adaptive power control system that uses a flag bit to switch between different TPC step sizes (e.g., a typical 1 dB step and a larger 8 dB step). This directly teaches a TPC command of a variable, or multilevel, size.
    • Motivation to Combine: Zeira’s suggestion of using “other values” for TPC step sizes would motivate a POSITA to seek out prior art that discloses specific techniques for implementing variable step sizes to gain known advantages, such as more rapid response to fast channel fading. Andersson provides a clear and readily implementable solution.
    • Expectation of Success: A POSITA would have recognized that Andersson's variable step size technique was compatible with Zeira's power control system. Implementing it by adding a flag bit to the TPC command would be a simple modification with a high expectation of achieving the desired benefit of faster power control adjustments.

4. Key Claim Construction Positions

  • "multilevel TPC command": Petitioner proposed that this term should be construed as "a TPC command of a variable size." This construction was argued to be supported by the patent’s specification, which contrasts a command for a change "by a fixed amount" with the "multi-level TPC command." This distinction suggests the latter is variable. This construction is central to the obviousness arguments, particularly the application of Zeira's disclosure of using "other values" and Andersson's explicit teaching of variable step sizes.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under 35 U.S.C. § 325(d) would be inappropriate. While the examiner considered Zeira, Krishnan, and Khan individually or in different combinations during prosecution, the specific combination and the arguments presented in the petition were argued to be novel. Specifically, Petitioner contended that the examiner never substantively considered Khan’s teaching of transmitting both scheduling grants and TPC commands on a single physical channel in the context of the other references. As this limitation was key to the allowance of the claims, Petitioner asserted that the new grounds raise substantial new questions of patentability that warrant review.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-2, 5-6, 8-9, 12-13, 15-16, 19-20, 22-23, 26-27, 29-30, 33-34, 36-37, and 40-41 of Patent 8,897,828 as unpatentable.