Sonos Inc v. Vocalife LLC

1. Case Identification

• Case #: IPR2022-00382
• Patent #: RE48,371
• Filed: December 29, 2021
• Petitioner(s): Sonos, Inc.
• Patent Owner(s): Vocalife LLC
• Challenged Claims: 22-41

2. Patent Overview

• Title: System for Enhancing Target Sound Signals
• Brief Description: The ’371 patent describes a system for enhancing a target sound signal, such as a person's voice, captured by a microphone array. The system uses a digital signal processor (DSP) to implement four functional units: a sound source localization unit, an adaptive beamforming unit, a noise reduction unit, and an echo cancellation unit.

3. Grounds for Unpatentability

Ground 1: Obviousness over Core System Reference - Claims 38-39 are obvious over Reuss in view of Dmochowski.

• Prior Art Relied Upon: Reuss (Patent 7,359,504) and Dmochowski (a 2007 IEEE journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Reuss disclosed a complete microphone array system with a DSP implementing three of the four claimed functional units: adaptive beamforming, noise reduction, and echo cancellation. Petitioner contended that Reuss also inherently disclosed the fourth unit, a sound source localization (SSL) unit, because its adaptive beamformer must locate the sound source to steer its directivity pattern toward a moving talker.
  • Motivation to Combine (for §103 grounds): Alternatively, if Reuss was found not to disclose the SSL unit, a person of ordinary skill in the art (POSITA) would combine Dmochowski with Reuss. A POSITA would incorporate Dmochowski’s well-known SSL algorithm (Steered Response Power or "SRP") and its specific delay calculation formula to improve Reuss’s system for its intended teleconferencing applications, thereby solving the same problem of determining a sound’s direction of arrival (DOA).
  • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success because SRP was a well-understood and predictable algorithm, and Reuss disclosed using commercially available DSPs fully capable of its implementation.

Ground 5: Obviousness over Alternative Core System Reference - Claims 38-39 are obvious over Chen in view of Dmochowski.

• Prior Art Relied Upon: Chen (Application # 2006/0147063) and Dmochowski (a 2007 IEEE journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: As an alternative primary reference, Petitioner asserted that Chen disclosed a microphone array system within a telephone that included a DSP performing adaptive beamforming, noise reduction, and echo cancellation. Petitioner argued that Chen’s DSP also determined the DOA of a user's voice, thus teaching the claimed SSL unit.
  • Motivation to Combine (for §103 grounds): Similar to the Reuss-based ground, Petitioner argued a POSITA would combine Dmochowski with Chen to add the specific SRP algorithm and its detailed delay calculation formula, which Chen described conceptually but did not explicitly provide. The motivation was to implement a known, high-performance algorithm to improve a known system (a speakerphone) for a known purpose (enhancing voice quality).
  • Expectation of Success (for §103 grounds): Success was expected due to the predictable nature of the SRP algorithm, its known benefits in reverberant environments like those described in Chen, and the capability of DSPs like those in Chen to execute such algorithms.
• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations including Li (for teaching delay calculation in terms of samples), Brandstein (for teaching the improved SRP-PHAT algorithm and specific adaptive beamformer designs), and Abutalebi (for teaching sub-band signal processing). These references were combined with the core Reuss/Dmochowski and Chen/Dmochowski combinations.

4. Key Claim Construction Positions

• Petitioner adopted constructions from a parallel district court litigation for the purposes of the IPR proceeding, including:
  • "adaptive beamforming": "a beamforming process where the directivity pattern of the microphone array is capable of being adaptively steered in the direction of a target sound signal emitted by a target sound source in motion."
  • "sound source localization unit": Plain and ordinary meaning, connoting "software/hardware in a DSP that includes functionality for locating a sound source."

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §314(a) based on Fintiv is inappropriate because all factors favor institution. Petitioner asserted that a stay of the parallel litigation is likely, the district court case is in its early stages with a trial date well after the statutory Final Written Decision deadline, and minimal investment has been made by the parties in that case. Petitioner also stipulated to not pursue any instituted grounds in the district court and argued the petition's merits are particularly strong because the primary references (Reuss and Chen) were never previously considered by the PTO, a court, or a jury.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 22-41 of Patent RE48,371 as unpatentable.