PTAB

IPR2017-01785

Shure Inc v. ClearOne Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Apparatuses for Echo Cancelation with Beamforming Microphone Arrays
  • Brief Description: The ’553 patent describes a system for audio conferencing that combines beamforming (BF) and acoustic echo cancellation (AEC). The disclosed method involves generating a plurality of signals from a microphone array, combining them into multiple fixed beams, performing AEC on each of these beamformed signals individually, and then selecting one or more of the resulting echo-canceled signals for transmission.

3. Grounds for Unpatentability

Ground 1: Claims 1-20 are obvious over Brandstein alone or in combination with Chen.

  • Prior Art Relied Upon: Brandstein (a 2001 technical book, "Microphone Arrays: Signal Processing Techniques and Applications") and Chen (Application # 2010/0128892).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Brandstein teaches nearly all elements of the independent claims. Brandstein's Figure 13.8 discloses a system with N microphones that feed a "Fixed Beamforming" unit to produce M fixed beams (where 1<M<N). These M signals are then simultaneously processed by an AEC unit to produce M echo-canceled signals. Finally, a "Voting" process selects one or more of these echo-canceled signals for output. This architecture was alleged to map directly to the core limitations of claims 1, 8, and 15, which require performing AEC on a plurality of combined signals from fixed beams before a selection step. Chen was cited primarily to teach the limitations of dependent claims related to using an orientation sensor to adjust beamforming characteristics.
    • Motivation to Combine (for §103 grounds): Petitioner asserted a POSITA would combine Brandstein with Chen because Brandstein explicitly suggests its technology is suitable for various communication terminals, including mobile phones, which is the subject of Chen. Adding Chen’s orientation sensor to Brandstein’s system was presented as a predictable improvement, applying a known technique (orientation-based adjustment) to a similar device (a beamforming system) to enhance its functionality.
    • Expectation of Success (for §103 grounds): A POSITA would have a reasonable expectation of success because combining Brandstein's established signal processing chain with Chen's orientation sensor functionality involved integrating known elements to achieve predictable results.

Ground 2: Claims 1-20 are obvious over Ishibashi alone or in combination with Chen and/or Reuss.

  • Prior Art Relied Upon: Ishibashi (Application # 2009/0052684), Reuss (Patent 7,359,504), and Chen (Application # 2010/0128892).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Ishibashi discloses a conferencing apparatus with all the key components: a microphone array, beamforming, a selection module, and an echo cancellation module. However, Ishibashi's system architecture selects the desired beamformed signal before performing echo cancellation. Petitioner argued that it would have been obvious for a POSITA to modify Ishibashi by performing AEC before the selection step. This modification would solve the known technical problem of performance degradation that occurs when an adaptive AEC filter must track a potentially time-varying, post-selection signal. Reuss was introduced to supply the teaching of noise filtering for certain dependent claims, and Chen was used, as in Ground 1, to address dependent claims requiring an orientation sensor.
    • Motivation to Combine (for §103 grounds): The primary motivation to modify Ishibashi's architecture was to improve system performance and avoid the complexity and inferiority of having an AEC filter track a switched input. A POSITA would combine Ishibashi with Reuss because both relate to teleconferencing, and adding a known noise reduction technique from Reuss was a simple, predictable way to improve audio quality. The motivation to add Chen’s teachings was to incorporate orientation-based features to improve the beamforming microphone array in Ishibashi's system.
    • Expectation of Success (for §103 grounds): A POSITA would expect success in reordering Ishibashi's processing steps for known performance benefits and in adding the well-understood noise filtering and orientation sensor technologies from Reuss and Chen.

4. Key Claim Construction Positions

  • "Fixed Beam": Petitioner argued that, based on the patent owner’s arguments during prosecution to distinguish the claims from the Kajala prior art (which disclosed adjustable beams), the term "fixed beam" should be construed as a "non-adjustable and non-adaptive beam that is focused in a predetermined direction." This construction was asserted to be a disclaimer of adjustable or dynamic beamforming applications.
  • "Performing an acoustic echo cancelation operation on the plurality of combined signals...": Petitioner proposed that this phrase, central to independent claims 1, 8, and 15, should be interpreted to encompass the processing of two or more beamformed signals delivered to the echo canceller either simultaneously or sequentially. This broader construction was proposed because the specification and file history are silent on the timing of delivery, and it would allow prior art disclosing sequential processing to meet the claim limitation.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-20 of Patent 9,264,553 as unpatentable.