DirecTV LLC v. Entropic Communications LLC

1. Case Identification

• Case #: IPR2024-01065
• Patent #: 8,363,681
• Filed: July 1, 2024
• Petitioner(s): DirecTV, LLC
• Patent Owner(s): Entropic Communications, LLC
• Challenged Claims: 1-40

2. Patent Overview

• Title: Method and Apparatus for Using Ranging to Improve Network Efficiency
• Brief Description: The ’681 patent discloses a method for synchronizing the local clocks of nodes in a communication network, such as a Multimedia over Coax Alliance (MoCA) network. The method involves exchanging packets to perform a ranging procedure that estimates the signal propagation delay between nodes, which is then used to adjust the clocks for improved synchronization.

3. Grounds for Unpatentability

Ground 1: Obviousness over IEEE802.3ah - Claims 1-3 and 6-10 are obvious over IEEE802.3ah.

• Prior Art Relied Upon: IEEE802.3ah (Institute of Electrical and Electronics Engineers Std. 802.3ah (Sep. 7, 2004)).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the IEEE802.3ah standard for Ethernet Passive Optical Networks discloses all limitations of the challenged method claims. IEEE802.3ah teaches a "ranging" procedure where a master node (OLT, first node) sends a GATE message to a slave node (ONU, second node). This message includes a timestamp (first packet clock time) and a Grant Start Time (scheduled arrival/response time). The ONU sets its local clock using the timestamp. The ONU then transmits a responsive packet back to the OLT at the scheduled Grant Start Time, which the OLT receives at an actual arrival time. Based on these times, the OLT calculates the round-trip time (RTT), which inherently includes the propagation delay.
  • Motivation to Combine (for §103 grounds): Not applicable for a single-reference ground.
  • Expectation of Success (for §103 grounds): Petitioner asserted that a person of ordinary skill in the art (POSITA) would have found it obvious to adjust node clocks using the calculated propagation delay (a component of RTT) rather than the full RTT to achieve more precise synchronization, as this would directly compensate for the time it took the initial message to travel between nodes.

Ground 2: Obviousness over Core Protocol and Hardware References - Claims 11-13, 16-23, 26-33, and 36-40 are obvious over IEEE802.3ah in view of Shvodian.

• Prior Art Relied Upon: IEEE802.3ah and Shvodian (Application # 2008/0101253).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground primarily addresses the system and device claims (11, 21, 31), which recite hardware elements like a "controller," "device module," and "memory." While IEEE802.3ah provides the core ranging protocol, Petitioner asserted that Shvodian supplies the explicit disclosure for these hardware components. Shvodian describes a "source node" in a coaxial network that functions as a "network device" and includes an apparatus with a "controller" and "memory" containing "computer programs" for controlling its operation.
  • Motivation to Combine (for §103 grounds): A POSITA would combine these references because both address the problem of determining RTT in a network. Shvodian provides a concrete hardware implementation (controller, memory, etc.) suitable for executing the abstract ranging protocol described in the IEEE802.3ah standard, thereby creating a complete and functional system.
  • Expectation of Success (for §103 grounds): Petitioner argued a POSITA would have a reasonable expectation of success because both references were designed for home networking environments and are compatible. Applying Shvodian's teachings on network device structure would be a straightforward way to implement the IEEE802.3ah protocol.

Ground 3: Obviousness over Core Protocol and Calculation References - Claims 1-3 and 6-10 are obvious over IEEE802.3ah in view of Frei.

• Prior Art Relied Upon: IEEE802.3ah and Frei (Application # 2007/0140127).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground strengthens the argument that calculating and using the specific "estimated propagation delay" would have been obvious. While IEEE802.3ah teaches calculating RTT, Frei was cited for its explicit teaching of calculating one-way propagation delay by dividing the RTT in half. Frei describes a formula, Propagation delay = (t4-t1-(t3-t2))/2, to derive this value from packet exchange timestamps. Frei further teaches transmitting this calculated propagation delay to the destination node to synchronize its clock.
  • Motivation to Combine (for §103 grounds): A POSITA seeking to improve the synchronization taught by IEEE802.3ah would have been motivated to consult a reference like Frei. After calculating RTT per IEEE802.3ah, a POSITA would find Frei's method of dividing RTT by two to be a well-known and logical next step to isolate the more precise one-way propagation delay needed for accurate clock adjustment.
  • Expectation of Success (for §103 grounds): Success would be expected because the combination involves applying a simple, explicit mathematical formula from Frei to the RTT value obtained from the compatible ranging protocol of IEEE802.3ah.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations including Ovadia (a paper on MoCA 1.0 networks) to provide explicit teachings of a mesh network operating under the MoCA standard, and Smith (Patent 7,821,958) to teach measuring packet arrival/transmission time using a "mean delay" to account for network variations.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under Fintiv is not warranted. A co-pending district court case exists, but no trial date has been set, discovery is not substantially complete, and no Markman hearing has occurred. Petitioner asserted that a Final Written Decision (FWD) in the IPR would issue months before any potential trial.
• Petitioner also contended that denial under §325(d) is inappropriate because the prior art combinations presented in the petition were never presented to or evaluated by the Examiner during the original prosecution of the ’681 patent.

5. Relief Requested

• Petitioner requests institution of inter partes review (IPR) and cancellation of claims 1-40 of Patent 8,363,681 as unpatentable.