Comcast Cable Communications, LLC v. Entropic Communications, LLC

1. Case Identification

• Case #: IPR2025-00180
• Patent #: 11,785,275
• Filed: December 6, 2024
• Petitioner(s): Comcast Cable Communications, LLC
• Patent Owner(s): Entropic Communications, LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: System and Method for Receiving a Television Signal
• Brief Description: The ’275 patent describes a wideband television receiver capable of simultaneously processing multiple non-contiguous radio frequency (RF) channels from a broad spectrum. The system uses a radio front end, an analog-to-digital converter (ADC), and a digital front end (DFE) to select, down-convert, and output a plurality of desired channels to one or more demodulators.

3. Grounds for Unpatentability

Ground A/B: Anticipation and Obviousness over Zhang - Claims 1-3, 5, 7-13, 15, and 17-20 are anticipated by or obvious over Zhang.

• Prior Art Relied Upon: Zhang (Application # 2003/0056221).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Zhang, which describes a multi-channel demodulator circuit for set-top boxes, discloses all limitations of the challenged claims. Zhang’s circuit includes an input terminal receiving a multi-channel RF signal, a down-converter (claimed "radio front end"), a high-speed ADC, and a digital channel demultiplexer (claimed "digital frontend" or "DFE"). Petitioner contended that Zhang’s DFE selects a plurality of desired channels, and its selector outputs them as a digital datastream to multiple demodulators that extract the encoded information. The petition asserted that Zhang explicitly teaches the broadcast channels can be non-contiguous and that implementing this is an obvious design choice to accommodate user channel selections across different frequency bands. Dependent claims related to satellite/cable channels and DVR/PVR storage were also argued to be disclosed by Zhang’s description of its system being a front-end for PVRs and compatible with cable and satellite systems.
  • Motivation to Combine (for §103 grounds): For the obviousness ground, Petitioner argued a person of ordinary skill in the art (POSITA) would find it obvious to operate Zhang's system to select non-contiguous channels to improve system flexibility and increase the number of accessible content channels for subscribers, which is a predictable variation.
  • Expectation of Success (for §103 grounds): A POSITA would have expected success as Zhang's system is already configured to receive channels across different frequency bands and is indifferent to whether selected channels are contiguous.

Ground C: Obviousness over Zhang and Pandey - Claims 2, 3, 12, and 13 are obvious over Zhang in view of Pandey.

• Prior Art Relied Upon: Zhang (Application # 2003/0056221) and Pandey (Patent 7,237,214).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addresses claims requiring the DFE to output the digital datastream via a serial interface (claims 2, 12) or a parallel interface (claims 3, 13). While arguing Zhang inherently discloses these, Petitioner asserted that, to the extent it does not, the combination with Pandey renders the claims obvious. Pandey was cited for its teaching of common methods for interconnecting functional blocks on an integrated circuit, including using either time-multiplexed serial interfaces or dedicated parallel interfaces depending on chip layout and resource constraints.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Zhang with Pandey because Zhang teaches implementing its digital components on a single chip, and Pandey provides a well-known, ubiquitous technique for connecting such components. Using Pandey’s methods would be a standard design choice to optimize the chip layout and interconnects for Zhang’s demodulator system.
  • Expectation of Success (for §103 grounds): Success would be expected as implementing serial or parallel interfaces was a standard, predictable process for connecting digital components on a chip, and the ’275 patent itself admits these are "commonly known methods."

Ground E: Obviousness over Zhang and Mirabbasi - Claims 4, 11-15, and 17-20 are obvious over Zhang in view of Mirabbasi.

• Prior Art Relied Upon: Zhang (Application # 2003/0056221) and Mirabbasi (a Nov. 2000 journal article).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground addresses claims requiring the ADC to comprise a first ADC for a digital in-phase (I) signal and a second ADC for a digital quadrature (Q) signal. Petitioner argued that Mirabbasi, a tutorial on RF receiver architectures, teaches a low-IF receiver that explicitly uses a complex mixer to generate analog I and Q signals, which are then separately digitized by a pair of ADCs.
  • Motivation to Combine (for §103 grounds): A POSITA would have been motivated to implement Zhang’s receiver using the low-IF architecture from Mirabbasi to gain its known advantages, such as eliminating DC offset issues (which are significant in CMOS technology used by Zhang), improving signal sampling feasibility, and correcting for gain/phase mismatches digitally.
  • Expectation of Success (for §103 grounds): A POSITA would have expected success as this was merely the application of a known technique (Mirabbasi's I/Q processing) to a similar system (Zhang's receiver) to obtain predictable benefits. The components and architecture in Mirabbasi were common and well-understood.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Zhang with Zhang ’933 (WO 2004/059933) to teach using a single time-multiplexed demodulator, and with Dong (Application # 2004/0250284) to teach DVR storage and picture-in-picture functionality. Further grounds combined Mirabbasi with these secondary references.

4. Key Claim Construction Positions

• Petitioner argued that no special claim constructions are necessary. However, should the Board construe "radio front end" (claim 11) and "digital frontend (DFE)" (claims 11-13) as means-plus-function terms, Petitioner provided proposed corresponding structures from the ’275 patent. Petitioner contended that even under this construction, the prior art (specifically Zhang) discloses equivalent structures performing the identical functions, and the claims remain unpatentable.

5. Arguments Regarding Discretionary Denial

• §314(a) / Fintiv: Petitioner argued against discretionary denial under Fintiv, stating that a stay has been requested in the parallel district court litigation, no trial date has been set, and court investment has been minimal. The petition asserts it presents compelling, meritorious challenges based on prior art that was never substantively considered during prosecution, favoring institution.
• §325(d): Petitioner argued that denial under §325(d) is unwarranted because the primary reference, Zhang, was not meaningfully considered by the Examiner. Although Zhang was cited in a large Information Disclosure Statement (IDS) during prosecution, the Examiner never discussed it and incorrectly stated in the reasons for allowance that the prior art of record did not teach the claimed DFE functionality, a key feature Petitioner asserts is clearly disclosed in Zhang.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of the ’275 patent as unpatentable.