Sonos Inc v. Implicit LLC

1. Case Identification

• Case #: To Be Assigned
• Patent #: 7,391,791
• Filed: March 9, 2018
• Petitioner(s): Sonos, Inc.
• Patent Owner(s): Implicit, LLC
• Challenged Claims: 1-3, 6-9, 12, 16, 19, and 23-25

2. Patent Overview

• Title: Synchronizing Rendering of Content at Multiple Devices
• Brief Description: The ’791 patent describes methods and systems for synchronizing the rendering of content (e.g., audio, video) across multiple networked devices. The technology addresses challenges that arise when devices operate in different "time domains" (i.e., have unsynchronized internal clocks) by designating a master device and one or more slave devices, calculating time differentials between them, and adjusting playback accordingly.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 6-9, 12, 16, 19, and 23-25 under §102 over Janevski

• Prior Art Relied Upon: Janevski (Patent 7,269,338).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Janevski discloses every element of the challenged claims. Janevski describes a "synchronized viewing system" for personal video recorders (PVRs) that mirrors the ’791 patent's system. Janevski's "initiator" PVR functions as the master device and its "participant" PVRs function as slave devices. The system synchronizes playback by first calculating a "time misregistration" between the clocks of the initiator and participant PVRs, which corresponds to the ’791 patent's device time differential. It then calculates a "frame misregistration" based on the amount of content played, corresponding to the rendering time differential. Janevski's PVRs then adjust playback by slowing down, speeding up, or rewinding content to correct this misregistration, directly mapping to the adjustment and rendering limitations of the challenged claims.
  • Key Aspects: Petitioner argued that Janevski’s two-phase process for determining and compensating for both device clock differences ("time misregistration") and playback progress differences ("frame misregistration") is functionally identical to the synchronization method claimed in the ’791 patent.

Ground 2: Obviousness of Claims 1-3, 6-9, and 12 under §103 over Janevski in view of Schneidewend

• Prior Art Relied Upon: Janevski (Patent 7,269,338) and Schneidewend (Patent 8,286,207).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented as an alternative, arguing that if the Board finds Janevski does not disclose the limitation "determining a ... source time domain" recited in claim 1, the combination with Schneidewend renders the claims obvious. Janevski teaches the core master-slave synchronization system. Schneidewend, which discloses a digital video receiving system, explicitly teaches receiving "system timing information" from a broadcast source (e.g., as part of the PSIP standard) and using it to generate a local scheduling clock. Petitioner contended this directly teaches the "source time domain" limitation.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Janevski with Schneidewend for clear and predictable reasons. A primary motivation would be to make Janevski's system compliant with established industry standards like the PSIP standard taught by Schneidewend. Furthermore, Schneidewend explicitly states that using a time reference from the broadcast source avoids "time clock inaccuracy," preventing issues like recording the wrong program. A POSITA would have recognized this benefit and applied Schneidewend's source-based timing to Janevski's synchronization system to improve its robustness and accuracy.
  • Expectation of Success: A POSITA would have had a high expectation of success in this combination. Both references operate in the same field of synchronizing digital media playback. Integrating a source-based time reference (from Schneidewend) into a PVR synchronization system (from Janevski) to establish a common timing baseline is a straightforward application of known engineering principles.

4. Key Claim Construction Positions

Petitioner argued that several claim terms required construction, and for the purpose of the inter partes review (IPR), it proposed constructions broad enough to encompass the Patent Owner's interpretations from co-pending litigation.

• "time domain differential" and related rendering elements: Petitioner argued these terms should, under the broadest reasonable construction, cover any synchronization of a time measure (either device time or rendering time) between a master and slave device during playback. This broad construction was adopted from the Patent Owner's litigation position to show that the claims are unpatentable even under the Patent Owner's own expansive view.
• Dependent Claim 7: Petitioner identified an error in the formula recited in claim 7 for calculating the time differential, noting it "flipped the location of the slave receive time and master receive time" compared to the formula disclosed in the ’791 patent's specification. Petitioner argued that, consistent with the Patent Owner's apparent position in litigation, the claim should be construed to match the correct formula disclosed in the specification.
• "determining a ... source time domain" (Claim 1): In the context of the obviousness ground, Petitioner argued this term refers to determining a reference of time defined by a clock used by the content source (e.g., a broadcaster). Petitioner contended that while Janevski inherently discloses this, Schneidewend explicitly teaches it by describing a system that uses timing information provided by a broadcast source to establish a local clock.

5. Relief Requested

• Petitioner requested the institution of an IPR and cancellation of claims 1-3, 6-9, 12, 16, 19, and 23-25 of the ’791 patent as unpatentable.