PTAB

IPR2014-00921

Ericsson Inc v. Intellectual Ventures I LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Generating a Nonsystematic Turbo Code
  • Brief Description: The ’783 patent is directed to methods and systems for correcting errors in data transmissions using turbo codes. The purported invention is a modification of prior art turbo coders that output both original (systematic) and encoded data, proposing instead a "nonsystematic" turbo coder that outputs only the encoded data to improve efficiency.

3. Grounds for Unpatentability

Ground 1: Obviousness of a Nonsystematic Turbo Coder - Claims 1, 2, 38, and 39 are obvious over Berrou in view of Forney.

  • Prior Art Relied Upon: Berrou (Patent 5,446,747) and Forney (a 1970 IEEE article titled "Convolutional Codes I: Algebraic Structure").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the ’783 patent itself admits Berrou teaches a standard prior art turbo coder. This includes all elements of independent claims 1 and 38—such as two parallel systematic convolutional encoders coupled to a data source via an interleaver—except for the final limitation requiring the system to output only the coded data. Berrou’s system is "systematic" because it outputs both the original data and the coded data. Forney was cited to teach the final "only coded output" limitation, as it describes "nonsystematic" encoders that output only coded data and explains their benefits. Dependent claims 2 and 39, which add a decoder, were mapped to Forney’s disclosure of a standard communications system that includes a decoder for receiving and decoding the coded signal to recover the original data.
    • Motivation to Combine: A POSITA would combine Berrou’s well-known turbo coder with Forney’s established technique of nonsystematic coding. The motivation was to achieve the predictable result of a more efficient coding system. By omitting the original data from the output, as taught by Forney, the system would conserve bandwidth and transmission power—addressing a known need for robust, efficient encoding in constrained environments.
    • Expectation of Success: Forney explicitly dismissed the "ignorant fear of error propagation" as the primary reason nonsystematic encoders were not widely used, stating such fears were "largely groundless," giving a POSITA a strong expectation of success.

Ground 2: Anticipation of a Nonsystematic Turbo Coder - Claims 1 and 38 are anticipated by Divsalar TCDSC.

  • Prior Art Relied Upon: Divsalar TCDSC (a NASA progress report from February 15, 1995, titled "Turbo Codes for Deep-Space Communications").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Divsalar TCDSC, a publication by the inventors of the ’783 patent published more than one year before the patent’s effective filing date, anticipates every limitation of claims 1 and 38. The reference’s Figure 1 was argued to disclose the complete structure of a turbo coder with two parallel systematic convolutional encoders and an interleaver. Critically, Figure 2 of Divsalar TCDSC disclosed a trellis termination scheme with a switch. Petitioner argued that when this switch is in position 'B', the system outputs only coded data elements and not the original data, thereby explicitly teaching the "only coded output" limitation required by the claims.
    • Key Aspects: This ground is particularly strong as it relies on the patent inventors’ own prior publication, which was not considered by the Examiner during the original prosecution, to show that the entire claimed invention was already in the public domain.

Ground 3: Obviousness of a Modulated Turbo Coder - Claims 23, 24, 60, and 61 are obvious over Berrou DTV in view of Ungerboeck.

  • Prior Art Relied Upon: Berrou DTV (a 1994 IEEE conference paper titled "Digital Television: Hierarchical Channel Coding Using Turbo-Codes") and Ungerboeck (a 1987 IEEE magazine article titled "Trellis-coded modulation with redundant signal sets").

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground targeted claims requiring the use of a multilevel modulator directly coupled to the turbo coder’s output. Petitioner argued Berrou DTV taught a turbo coder for digital television signals that disclosed a "Joint coding-and-mapping scheme" using 64QAM, a type of multilevel modulation. This combination inherently taught directly coupling the modulator to the coder’s outputs. For the dependent claims (24 and 61) requiring "trellis code modulation" (TCM), Petitioner relied on Ungerboeck. Ungerboeck was presented as the foundational reference on TCM, which was a widely known and effective modulation technique at the time of the invention.
    • Motivation to Combine: A POSITA would combine Berrou DTV's turbo coder system with the well-known TCM taught by Ungerboeck. The motivation was to achieve the predictable result of improved encoding performance and greater bandwidth efficiency, as the benefits of TCM were universally recognized in the art.
    • Expectation of Success: Combining a known coding scheme (turbo codes) with a known advanced modulation scheme (TCM) to improve performance was a standard design choice for a POSITA, who would have had a high expectation of success.

  • Additional Grounds: Petitioner asserted additional obviousness and anticipation challenges based on alternative combinations of prior art teaching turbo coders (e.g., Robertson, Palicot), nonsystematic coding, and known modulation (e.g., Le Goff), demodulation (e.g., Massey), and decoding techniques.

4. Key Claim Construction Positions

  • Systematic vs. Nonsystematic: Petitioner argued these were well-understood terms. "Systematic" refers to a coder that outputs both the original data and the encoded data. "Nonsystematic" refers to a coder that outputs only the encoded data, which is the central feature of the challenged claims.
  • Coupled: Petitioner proposed that "coupled" should be interpreted broadly as a connection of components, regardless of whether intervening structures exist. This interpretation was based on the patent’s own description.
  • Directly Coupled / Signal Directly From: These terms, present in claims 23 and 60, were added during prosecution to overcome a rejection over a reference (Le Goff) that included an interleaver between the coder and modulator. Petitioner argued that based on this history, "directly" should be construed to mean a connection without an intervening interleaver, but which may include other simpler components like puncturing functions or multiplexers.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-5, 23-24, 38-42, and 60-61 of the ’783 patent as unpatentable.