PTAB

IPR2017-00210

Apple Inc. v. California Institute of Technology

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1. Case Identification

2. Patent Overview

  • Title: Serial Concatenation of Interleaved Convolutional Codes Forming Turbo-Like Codes
  • Brief Description: The ’710 patent relates to error-correcting codes, specifically methods and systems for encoding signals using irregular repeat-accumulate (IRA) codes. The invention uses a first coder (an irregular repeater) and a second coder (an accumulator) connected by an interleaver to improve data transmission reliability.

3. Grounds for Unpatentability

Ground 1: Anticipation over Frey - Claims 1 and 3 are anticipated by Frey.

  • Prior Art Relied Upon: Frey, B. J. and MacKay, D. J. C., “Irregular Turbocodes,” (published on or before March 20, 2000).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Frey, which was not considered during prosecution, teaches every element of claims 1 and 3. Frey discloses a method of encoding a signal using an irregular turbocode that operates on blocks of data. This involves a "first encoding" step where a data block is partitioned into sub-blocks, and the data elements in different sub-blocks are repeated a different number of times (irregular repetition). The resulting data is then interleaved ("permuted") and subjected to a "second encoding" by a convolutional encoder with a rate "close to one" (e.g., 0.74, which is within the proposed construction of 50% of one).
    • Key Aspects: Petitioner contended that Frey’s disclosure of an irregular turbocode structure with an irregular repeater, a permuter, and a subsequent convolutional encoder directly maps to the claimed method steps, including the variable rate of the first coder and the "substantially close to one" rate of the second coder required by claim 3.

Ground 2: Obviousness over Divsalar and Frey - Claims 1-8 and 11-14 are obvious over Divsalar in view of Frey.

  • Prior Art Relied Upon: Divsalar et al., “Coding Theorems for ‘Turbo-Like’ Codes,” (Mar. 1999) and Frey.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Divsalar teaches a regular repeat-accumulate (RA) code structure comprising a repeater (first encoder), an interleaver, and a rate-1 accumulator (second encoder). This structure teaches most limitations of the challenged claims. The key missing element is the "irregular" repetition of the first encoding step. Frey explicitly teaches that making turbocodes irregular—repeating some bits more than others—improves performance over regular turbocodes.
    • Motivation to Combine: A POSITA would combine Frey’s teaching of irregularity with Divsalar’s RA codes. Both references are in the same field of error-correcting "turbo-like" codes and share a similar architecture (repeater-interleaver-encoder). Frey’s conclusion that irregularity "clearly performs better" would have provided a strong motivation to apply this known technique to improve the performance of Divsalar’s RA codes. The modification would be a simple matter of making Divsalar’s repeater repeat bits irregularly, as taught by Frey.
    • Expectation of Success: A POSITA would have had a high expectation of success. The combination involved applying a known, performance-enhancing technique (irregularity) to a known code structure (RA codes) to achieve a predictable improvement. The similarity in the underlying code structures would have made the integration straightforward.

Ground 3: Obviousness over Divsalar, Frey, and Luby97 - Claims 15-17, 19-22, and 24-33 are obvious over Divsalar in view of Frey and further in view of Luby97.

  • Prior Art Relied Upon: Divsalar, Frey, and Luby, M. et al., “Practical Loss-Resilient Codes,” (1997).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground builds on the combination of Divsalar and Frey to address claims (e.g., independent claim 15) that recite receiving a "stream of bits." While the combination of Divsalar and Frey teaches the core irregular repeat-accumulate structure, Luby97 supplies the teaching of processing data as a "stream of data symbols... partitioned and transmitted in logical units of blocks."
    • Motivation to Combine: Luby97, which first introduced irregularity, also taught a common method of handling data. A POSITA would be motivated to modify the encoder from Divsalar and Frey to accept a "stream" of bits as taught by Luby97. This modification would enable the encoder to handle data in a conventional, real-time manner, which was a common and desirable feature for coding systems.
    • Key Aspects: The incremental addition of Luby97 addresses specific claim language related to data handling ("stream of bits") not explicitly detailed in Divsalar or Frey. This ground argues that combining these three references renders the apparatus claims (e.g., "coder," "coding system") obvious, as all the functional elements were known and their combination was predictable.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including:

    • Claims 10 and 23 are obvious over Divsalar and Frey, further in view of Pfister. Pfister was argued to teach using two accumulators in series to improve performance, motivating a POSITA to add a second accumulator to the Divsalar/Frey combination.

4. Key Claim Construction Positions

  • "close to one" (Claims 1 and 3): Petitioner proposed this term should be construed to mean "within 50% of one." This construction was based on the patent’s specification, which provides an example: "the inner code can have a rate that is close to one, e.g., within 50%." Petitioner also pointed to the prosecution history, where the Patent Owner amended a claim to replace "a rate close to one" with "a rate within 50% of one" to overcome a rejection, suggesting the terms are related and that "close to one" is at least as broad as "within 50%."

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-8, 10-17, and 19-33 of the ’710 patent as unpatentable under 35 U.S.C. §§ 102 and 103.