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. The system uses a radio front end, an analog-to-digital converter (ADC), and a digital front end (DFE) to select desired channels from a broad spectrum and output them to one or more demodulators.

3. Grounds for Unpatentability

Ground 1: Anticipation and Obviousness over Zhang - Claims 1-3, 5, 7-13, 15, and 17-20 are anticipated under 35 U.S.C. §102 or obvious under 35 U.S.C. §103 by 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 every element of the challenged claims. Zhang’s circuit includes an input terminal, a down-converter (the claimed "radio front end"), a high-speed ADC, and a demultiplexer (the claimed "DFE"). This DFE selects target RF channels from a digitized signal and outputs them as a datastream to a bank of demodulators, which then extract the encoded information. Petitioner contended that Zhang explicitly teaches that the received RF channels need not be contiguous, meeting a key limitation of the claims.
  • Motivation to Combine (for §103 ground): The obviousness argument was presented as an alternative. Petitioner asserted that even if Zhang does not explicitly disclose selecting non-contiguous channels, a person of ordinary skill in the art (POSITA) would have understood that user channel selection is based on desired content, not frequency location, making selection of non-contiguous channels inherently obvious. A POSITA would be motivated to implement Zhang’s system to handle non-contiguous channels to improve flexibility and access a wider range of content for subscribers.
  • Expectation of Success: A POSITA would have an expectation of success because Zhang’s system is already designed to select a number of target channels from a wider band, and selecting non-contiguous channels requires no structural change to the disclosed architecture.

Ground 2: 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 2000 IEEE Communications Magazine article).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims 4 and 14, which require a first ADC for an in-phase (I) signal and a second ADC for a quadrature (Q) signal. While Zhang discloses a single ADC, Petitioner argued Mirabbasi explicitly teaches a low-intermediate frequency (low-IF) receiver architecture that uses complex mixing to generate separate analog I and Q signals, which are then digitized by two separate ADCs.
  • Motivation to Combine: A POSITA would combine Zhang with Mirabbasi to gain the known advantages of a low-IF architecture, such as eliminating DC offset and reducing gain/phase mismatches, which were known problems in the receiver designs of the time. Mirabbasi provides a well-known, advantageous implementation for the front-end and ADC stages of a receiver like Zhang’s.
  • Expectation of Success: Success would be expected because implementing Mirabbasi's well-documented dual-ADC, I/Q processing front-end into Zhang's similar receiver architecture was a known technique for improving performance and involved combining predictable and compatible components.

Ground 3: Obviousness over Zhang and Dong - Claims 5, 6, 15, and 16 are obvious over Zhang in view of Dong.

• Prior Art Relied Upon: Zhang (Application # 2003/0056221) and Dong (Application # 2004/0250284).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground targeted claims related to storing extracted information for a digital video recorder (DVR) (claims 5, 15) and outputting information for a picture-in-picture (PnP) display (claims 6, 16). Petitioner asserted that while Zhang’s system provides the multi-channel demodulation foundation, Dong explicitly discloses a set-top box architecture where demodulated data is output as a stream for PVR storage and a separate stream for PnP operations.
  • Motivation to Combine: A POSITA would combine the teachings to add valuable, highly demanded consumer features (DVR and PnP) to Zhang's multi-channel receiver. Providing these features would enhance the user experience, making the product more commercially attractive.
  • Expectation of Success: The combination was a routine integration of known technologies. Connecting the output of a demodulator like Zhang's to a DVR or PnP controller as taught by Dong was a common and predictable design choice for television receivers.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Zhang with Pandey (Patent 7,237,214) for claims requiring serial and parallel interfaces, and combining Zhang with Zhang ’933 (WO 2004/059933) for claims directed to using a single, time-multiplexed demodulator.

4. Key Claim Construction Positions

• "radio front end" and "digital frontend (DFE)": Petitioner argued that if these terms are construed as means-plus-function terms under pre-AIA 35 U.S.C. §112, paragraph 6, the structures disclosed in the prior art are the same as or equivalent to the corresponding structures in the ’275 patent. For example, Zhang’s down-converter 210 was argued to be structurally equivalent to the ’275 patent’s radio front end, and Zhang’s demultiplexer 230 was argued to be structurally equivalent to the claimed DFE.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) and §325(d). Regarding Fintiv factors, Petitioner asserted that the parallel district court case was in its earliest stages with no trial date set, and that the IPR challenges all claims while the litigation involves a subset. Regarding §325(d), Petitioner argued the examiner erred by failing to consider the primary prior art (Zhang), even though it was cited in an Information Disclosure Statement (IDS). Petitioner contended the examiner dismissed the IDS materials without substantive review, constituting a material error that warrants institution of the IPR.

6. Relief Requested

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