PTAB

IPR2017-00219

Apple Inc. v. California Institute of Technology

Title: Serial Concatenation of Interleaved Convolutional Codes Forming Turbo-Like Codes
Brief Description: The ’710 patent discloses methods and systems for error-correcting codes, specifically relating to 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 create codes with improved performance characteristics.

Prior Art Relied Upon: Divsalar ("Coding theorems for 'turbo-like' codes," a 1999 paper) and Luby ("Analysis of Low Density Codes and Improved Designs Using Irregular Graphs," a 1998 paper).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Divsalar taught a complete repeat-accumulate (RA) coding system that included all elements of the challenged claims except for irregularity. Divsalar’s system used a regular repeater (first coder), an interleaver, and an accumulator (second coder). Luby taught the missing element: that using irregular codes, where some bits are repeated more than others, results in codes that are "far superior to any regular code." The combination of Divsalar’s structure with Luby’s teaching of irregularity renders the claims obvious.
- Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine the teachings to improve the performance of Divsalar's known RA codes. Luby’s paper demonstrated significant performance gains from irregularity, and applying this known technique to improve other coding systems like Divsalar’s was a predictable path for innovation in the field.
- Expectation of Success: A POSITA would have had a high expectation of success. The modification was a routine design choice—simply changing Divsalar’s regular repeater to an irregular one as taught by Luby—and did not present significant technical challenges.

Prior Art Relied Upon: Divsalar (1999 paper), Luby (1998 paper), and Luby97 ("Practical Loss-Resilient Codes," a 1997 paper).
Core Argument for this Ground:
- Prior Art Mapping: This ground built upon the combination of Divsalar and Luby to establish the core irregular RA coder. The additional reference, Luby97, was asserted to teach the limitation of processing a "stream of bits." Luby97 described receiving data to be encoded in a "stream of data symbols [] is partitioned and transmitted in logical units of blocks."
- Motivation to Combine: The motivation to combine Divsalar and Luby remained the same (performance improvement). A POSITA would have been further motivated to incorporate the "stream" processing taught by Luby97 to make the resulting encoder capable of handling real-time data, which was a common and well-understood design consideration for coding systems.

Prior Art Relied Upon: Divsalar (1999 paper), Luby (1998 paper), and Pfister ("The Serial Concatenation of Rate-1 Codes," a 1999 paper).
Core Argument for this Ground:
- Prior Art Mapping: This ground also built upon the core combination of Divsalar and Luby. To meet the specific limitation of claim 10, which requires the second encoding step to "utilize[] two accumulators," Petitioner relied on Pfister. Pfister explicitly taught "Repeat-Accumulate-Accumulate" (RAA) codes, which are Divsalar's RA codes with an extra accumulator added to the end of the encoding chain.
- Motivation to Combine: Pfister explicitly built on Divsalar's work and demonstrated that adding a second accumulator improved the code's performance. Petitioner argued this constituted an explicit suggestion for a POSITA to combine the teachings of Pfister with the RA codes of Divsalar to achieve a known benefit.
Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 23 based on the combination of Divsalar, Luby, Luby97, and Pfister, relying on similar theories to add the "second accumulator" teaching of Pfister to the combination established in Ground 2.

"close to one" (claims 1 and 3): Petitioner argued this term should be construed to mean "within 50% of one." This construction was asserted to be compelled by the ’710 patent's specification, which provides an explicit example: "a rate that is close to one, e.g., within 50%." Petitioner further argued this is consistent with the prosecution history, where the Patent Owner amended a different claim to narrow "close to one" to "within 50% of one" to overcome a rejection, suggesting the original term is at least that broad.

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. §103.