DirecTV LLC v. Entropic Communications LLC

1. Case Identification

• Case #: IPR2024-01063
• Patent #: 8,320,566
• Filed: July 1, 2024
• Petitioner(s): DirecTV, LLC
• Patent Owner(s): Entropic Communications, LLC
• Challenged Claims: 1-6 and 12

2. Patent Overview

• Title: Communications Transmission Using Orthogonal Frequency Division Multiple Access (OFDMA)
• Brief Description: The ’566 patent discloses methods for data transmission in wired or wireless networks, such as those compliant with the Multimedia over Coax Alliance (MoCA) standard, using OFDMA. The invention focuses on applying a pseudorandom noise sequence to scramble quadrature amplitude modulated (QAM) symbols on subcarriers to reduce interference.

3. Grounds for Unpatentability

Ground 1A: Claims 1-3 are obvious over Cleveland in view of Hayashino.

• Prior Art Relied Upon: Cleveland (2008/0112359) and Hayashino (5,682,376).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Cleveland discloses a wireless OFDMA network that provides a plurality of transmitting devices, a set of available subcarriers, and a method for allocating subsets of those subcarriers. Hayashino, an OFDM reference, was argued to teach the remaining limitations of claims 1-3. Specifically, Hayashino teaches applying an element from a pseudorandom noise (PN) sequence to each subcarrier to perform a predetermined transformation (scrambling) on QAM symbols before transmission. Petitioner asserted Hayashino discloses advancing a PN sequence generator to provide a unique element for each subsequent subcarrier until the last used subcarrier is transformed.
  • Motivation to Combine: Petitioner contended a person of ordinary skill in the art (POSITA) would combine Hayashino's scrambling technique with Cleveland's OFDMA network to solve the known problem of high peak-to-average power ratio (PAR). Reducing PAR lessens signal interference and power concentration, which in turn allows for the use of more efficient and less costly transmitters, a clear benefit for the battery-powered mobile devices in Cleveland's network.
  • Expectation of Success: Petitioner asserted a POSITA would have a reasonable expectation of success because both references operate in the analogous fields of OFDM/OFDMA and address similar interference problems. Implementing Hayashino’s PN sequence circuitry into Cleveland’s transmitter was presented as a routine and predictable engineering task that would not alter the fundamental operation of Cleveland's system.

Ground 2A: Claims 1-3 are obvious over Scheim in view of Tzannes.

• Prior Art Relied Upon: Scheim (2008/0233966) and Tzannes (6,961,369).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Scheim discloses a conventional OFDMA network with multiple transmitting devices and subcarriers, and a method for allocating subsets of those subcarriers to users. Scheim addresses inter-cell interference by using a sequence generator (a linear feedback shift register) to randomly allocate resources. Tzannes was argued to teach scrambling the phase of QAM symbols using a pseudo-random number generator to provide a unique phase shift value for each carrier signal, thereby performing a predetermined transformation to reduce PAR.
  • Motivation to Combine: A POSITA seeking to improve the performance of Scheim's OFDMA network and further mitigate interference would be motivated to incorporate the phase scrambling techniques taught by Tzannes. Both references are directed to overcoming inefficiencies in OFDM-based networks arising from non-uniformly distributed carrier signals, making Tzannes's solution directly applicable to the problems faced in Scheim.
  • Expectation of Success: Petitioner argued the combination would have been successful because both references utilize QAM mapping and address the same fundamental issues. The petition asserted that incorporating Tzannes's phase randomizer into Scheim's transceiver would be a predictable modification for a POSITA and an exercise of ordinary skill.

Ground 1D: Claims 6 and 12 are obvious over Cleveland-Hayashino in view of Mutagi and Ohana.

• Prior Art Relied Upon: Cleveland (2008/0112359), Hayashino (5,682,376), Mutagi ("Pseudo noise sequences for engineers," 1996), and Ohana (2008/0298241).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds on the Cleveland-Hayashino combination. Petitioner argued Mutagi establishes that using a PN-15 sequence (a limitation of claim 4, on which claims 6 and 12 depend) was a well-known and obvious design choice for a POSITA. Petitioner then argued that Ohana, which is directed to improving MoCA networks, explicitly teaches the remaining limitations of claims 6 and 12: a receiving network device comprising a network coordinator and packets comprising a resource reservation request packet.
  • Motivation to Combine: A POSITA would be motivated to incorporate Ohana's teachings to increase data speeds in the combined Cleveland-Hayashino network. Ohana teaches using persistent reservation requests to reduce latency, addressing the increasing demand for higher data rates in wireless and wired networks of the time.
  • Expectation of Success: Petitioner asserted that success was expected because Ohana discloses known components (network coordinators, reservation requests) for use in coordinated networks like the MoCA networks relevant to the ’566 patent. Implementing these features was argued to be an exercise of ordinary skill.
• Additional Grounds: Petitioner asserted additional obviousness challenges for claims 4 and 5 based on Cleveland-Hayashino in view of Mutagi, and Ting (a 2007 Ph.D. thesis), as well as parallel grounds based on the Scheim-Tzannes combination with the same additional references.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under Fintiv, asserting that no trial date has been set in the co-pending district court litigation and that discovery is in its early stages. The petition contended that the median time to trial in the relevant district (CDCA) is significantly longer than the statutory deadline for a Final Written Decision (FWD), ensuring the IPR would conclude well before any potential trial. Petitioner also argued against denial under §325(d), stating that the prior art combinations presented in the petition were not previously considered by the USPTO examiner during prosecution.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-6 and 12 of the ’566 patent as unpatentable.