PTAB

IPR2017-00701

Apple Inc v. California Institute Of Technology

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Serial Concatenation of Interleaved Convolutional Codes Forming Turbo-Like Codes
  • Brief Description: The ’032 patent discloses methods for generating error-correcting codes, specifically irregular repeat-accumulate (IRA) codes. The technology involves using an outer coder that irregularly repeats message bits, an interleaver, and an inner coder (accumulator) to generate a sequence of parity bits for transmission.

3. Grounds for Unpatentability

Ground 1: Claims 1-10 are obvious over Ping in view of MacKay, Divsalar, and Luby97.

  • Prior Art Relied Upon: Ping (a 1999 article on low-density parity check codes), MacKay (a 1999 article on irregular Gallager codes), Divsalar (a 1998 paper on repeat-accumulate codes), and Luby97 (a 1997 paper introducing irregularity).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the primary reference, Ping, discloses the core elements of independent claim 1. Specifically, Ping teaches a two-stage encoding method where an outer low-density generator matrix (LDGM) coder generates intermediate sums of information bits, which are then processed by an inner accumulator. This inner accumulator recursively calculates each new parity bit based on the previous parity bit and a new sum of information bits, directly corresponding to the recursive formula recited in claim 1. Petitioner contended that Ping’s disclosed method generates a sequence of parity bits based on a collection of message bits for transmission, meeting the fundamental steps of the claim.
    • Motivation to Combine: Petitioner asserted that a person of ordinary skill in the art (POSITA) would have been motivated to combine the references for clear reasons of performance improvement and practical implementation.
      • Ping with MacKay (for irregularity): Ping’s code is "regular," meaning each information bit contributes to the same number of parity bits. MacKay, which explicitly credits Ping’s author for reviving interest in the field, teaches that "irregular" codes (where different information bits contribute to different numbers of parity bits) exhibit superior performance. A POSITA would combine MacKay's teaching of non-uniform column weights with Ping's LDPC-accumulate code structure to achieve the well-documented performance benefits of irregularity. This modification would directly result in the "irregular repeats" required by claim 1.
      • Ping with Divsalar (for repetition): Petitioner argued that an obvious way to implement Ping’s requirement—that each information bit contributes to a set number of summations—is to use a simple "repeater" component. Divsalar explicitly teaches a "repeat and accumulate" (RA) encoder structure using a repeater as the outer coder. A POSITA would combine Divsalar’s cost-effective and straightforward repeater with Ping’s architecture as a natural way to implement Ping’s code, thereby explicitly teaching the "repeats" of message bits.
      • Combination with Luby97 (for data streams): Ping teaches encoding blocks of data. Luby97 teaches that data is often received in a "stream" which is then partitioned into blocks for processing. To the extent Ping does not inherently teach stream-based processing, a POSITA would have found it obvious to adapt Ping’s block-based encoder to handle real-time data streams as taught by Luby97, a common and practical modification.
    • Expectation of Success: Petitioner argued that a POSITA would have a high expectation of success, as the combination involves applying known techniques (irregularity, repeaters) to a known type of error-correcting code (LDPC-accumulate) to achieve predictable improvements in performance and efficiency. The underlying principles of the references are highly compatible.

4. Key Claim Construction Positions

  • Equation in "generating" step of claim 1: Petitioner argued for adopting the Board's construction from a prior IPR (IPR2015-00060), stating the equation means: "The parity bit xj is the sum of (a) the parity bit xj-1 and (b) the sum of a number, 'a' of randomly chosen irregular repeats of the message bits." This construction was central to mapping Ping’s recursive formula and the modifications from the secondary references.
  • "irregular": Citing the same prior IPR, Petitioner asserted that "irregular" means "different message bits or groups of message bits contribute to different numbers of parity bits." This construction was critical to the motivation to combine Ping with MacKay, as MacKay explicitly teaches creating codes with this property to improve performance.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-10 of the ’032 patent as unpatentable under 35 U.S.C. §103.