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`Paper No. ___
`Filed: November 9, 2017
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`_____________________________
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`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`_____________________________
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`
`APPLE INC.,
`Petitioner,
`
`v.
`
`CALIFORNIA INSTITUTE OF TECHNOLOGY,
`Patent Owner.
`_____________________________
`
`Case IPR2017-002971
`Patent No. 7,916,781
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`
`
`_____________________________
`
`
`
`PATENT OWNER’S RESPONSE
`PURSUANT TO 37 C.F.R. § 42.120
`
`
`1 Case IPR2017-00423 has been consolidated with this proceeding.
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`

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`TABLE OF CONTENTS
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`Dr. Davis’s evasiveness during his deposition undermines his
`
`STATEMENT OF PRECISE RELIEF REQUESTED .................................. 1
`I.
`INTRODUCTION AND OVERVIEW OF ARGUMENT ............................ 1
`II.
`III. OVERVIEW OF THE ART AND CITED REFERENCES .......................... 5
`A. MacKay (EX1002) .............................................................................. 7
`B.
`Ping (EX1003) .................................................................................... 8
`IV. WEIGHT TO BE GIVEN RESPECTIVE EXPERT TESTIMONY ............ 10
`A. Dr. Davis’s testimony includes basic errors demonstrating a
`lack of credibility .............................................................................. 10
`B.
`Dr. Davis’s testimony is not independent .......................................... 13
`C.
`credibility.......................................................................................... 14
`V. GROUND 1: PING IN VIEW OF MACKAY DOES NOT RENDER
`CLAIMS 13-15, 18 AND 22 OBVIOUS .................................................... 15
`A.
`Legal Principles ................................................................................ 16
`B.
`discloses information bits in a variable number of subsets ................ 18
`C.
`MacKay ............................................................................................ 23
`1. Ping is already irregular as defined by MacKay ............................. 23
`2. The proposed modification would eliminate Ping’s stated
`improvement ................................................................................. 30
`3. Petitioner’s additional arguments regarding motivation to
`combine fail .................................................................................. 33
`4. Dr. Davis’s claim that MacKay’s irregularity is ill-defined
`indicates a lack of motivation to combine ..................................... 37
`D.
`The petition inadequately defines its proposed modification ............. 39
`E. Modifying Ping in view of MacKay would not be expected to
`succeed. ............................................................................................ 44
`VI. GROUND 2: THE COMBINATION OF PING, MACKAY AND
`COOMBES DOES NOT RENDER CLAIM 16 OBVIOUS ....................... 49
`VII. GROUND 3: PING DOES NOT ANTICIPATE CLAIMS 19-21 ............... 49
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`The Petition fails to establish that either Ping or MacKay
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`A POSA would not be motivated to modify Ping in view of
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`-i-
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`

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`VIII. OBJECTIVE INDICIA OF NON-OBVIOUSNESS.................................... 51
`A. Nexus between the Objective Evidence and the Claims .................... 52
`B.
`Long-felt need and failure of others .................................................. 54
`C.
`Industry Praise .................................................................................. 57
`D. Unexpected Results........................................................................... 59
`E.
`Commercial Success ......................................................................... 60
`IX. CONCLUSION .......................................................................................... 62
`X. APPENDIX ................................................................................................ 64
`
`-ii-
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`

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`I.
`
`STATEMENT OF PRECISE RELIEF REQUESTED
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`In IPR2017-00297, Apple, Inc. (“Petitioner”) filed a petition for review of
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`claims 1-12 and 19-21 of the U.S. Patent No. 7,916,781 (the “’781 patent”,
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`EX1101). The Board issued its decision instituting trial (“297 Decision,” Paper
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`16) on Ground 2 with respect to claims 19-21. In IPR2017-00423, Petitioner filed
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`a petition for inter partes review of claims 13-22 of under two grounds.2 The
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`Board issued its decision instituting trial (“423 Decision,” Paper 16) on both
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`grounds with respect to claims 13-16, 18, and 22 and consolidated that proceeding
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`with IPR2017-00297. The patent owner (“PO” or “Caltech”) hereby requests that
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`the Board now issue a final written decision rejecting all grounds of challenge still
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`remaining, and confirming that claims 13-16 and 19-22 are not unpatentable.
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`For purposes of the response, Caltech will refer to the instituted grounds of
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`the IPR2017-00423 petition as Grounds 1 and 2, and the instituted ground of the
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`IPR2017-00297 petition as Ground 3.
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`II.
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`INTRODUCTION AND OVERVIEW OF ARGUMENT
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`The ’781 patent is one of four Caltech patents that resulted from research
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`performed by the inventors, Drs. Jin, Khandekar, and McEliece, in 1999-2000.
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`The patents claim inventions directed to a revolutionary class of error-correction
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`2 Caltech herein refers to the -00423 Petition as “Pet.” and the -00297 Petition
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`as “297 Pet.”
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`-1-
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`

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`codes, dubbed “irregular repeat and accumulate codes,” or “IRA codes,” which
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`rivaled and surpassed the performance of the best known codes at that time. One
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`of the features that made IRA codes unique and superior to other known codes,
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`however, was their capability of being encoded and decoded with linear
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`complexity, a critical requirement for most practical applications. No other code
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`known at the time could boast linear encoding, linear decoding, and performance
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`near the theoretical Shannon limit.
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`The IRA encoders and decoders described in the ’781 patent were the
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`culmination of more than a year of research and analysis by the inventors into
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`different code structures. As even Petitioner’s expert acknowledges, the field of
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`error correction coding is a complex and highly unpredictable one. Design of new
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`error correction codes typically requires extensive experimentation by experts in
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`the field in order to identify a viable code structure, create useable encoders and
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`decoders, and demonstrate the capabilities of the code’s performance. Even simple
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`code structures require rigorous simulation and analysis to determine whether they
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`can be practically and reliably encoded and decoded, and features that may
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`improve performance in one code may have detrimental effects in others.
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`In arguing that the instituted claims are unpatentable, Petitioner relies chiefly
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`on two prior art references: the MacKay reference, which discloses randomly
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`generated parity check matrices (which are “irregular” in the sense that 11of 12
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`-2-
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`

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`columns are weight 3 and 1 of 12 columns weight 9), and the Ping reference,
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`which describes a method of improving random parity check matrices of the type
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`described by MacKay by imposing certain structural constraints to the parity check
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`matrix.
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`Petitioner’s obviousness challenges are lacking in many respects. In
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`ascribing motivation to combine the asserted references, Petitioner attempts to take
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`MacKay’s teachings about non-uniform column weights in a full parity check
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`matrix and apply it to only a part of Ping’s parity check matrix. Yet nothing in
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`MacKay suggests, let alone teaches, the propriety of applying a general aspect of a
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`full matrix to merely a part of a matrix in a different code. To the contrary,
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`Petitioner’s proposed combination ignores and destroys fundamental constraints of
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`Ping’s codes—constraints that Ping explicitly imposes for performance reasons. In
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`fact, Ping’s code is presented as an improvement over random parity-check
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`matrices like those in MacKay, and modifying it in light of MacKay would be
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`viewed as a step backwards. Moreover, Ping’s parity check matrix as a whole in
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`its unmodified state is already “irregular” (in fact, more “irregular”) as the MacKay
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`codes. There would simply be no motivation to modify Ping in light of the fact it
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`already achieves what MacKay teaches, and the proposed modification would
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`eliminate the very improvements Ping proposes.
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`-3-
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`

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`The petition is further flawed in its nondescript proposal to modify Ping’s
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`Hd submatrix by “setting some columns to weight 9 and others to weight 3.” Pet.
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`36. Aside from the fact that MacKay does not teach such a modification, the
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`petition fails to specifically describe how such a modification would be
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`accomplished for generating a workable code. Among other things, the petition
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`materials provide no guidance or specificity as to which columns should be
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`modified, how many should be modified, and how such a modification would
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`maintain the fundamental constraints of Ping’s and MacKay’s code, such as
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`avoidance of error floors and an increased recurrence distance.
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`Not only does the petition lack a meaningful degree of specificity for how
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`the modification would be accomplished, the petition fatally suffers from a
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`complete lack of analysis that its proposed combination would be expected to
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`succeed. A person of ordinary skill in the art would have known that error-
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`correcting codes were an unpredictable field of endeavor, yet nowhere in the
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`petition is expectation of success addressed. The petition ignores this critical
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`requirement of an obviousness inquiry under Graham v. John Deere, and can be
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`rejected for this reason alone.
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`Furthermore, objective indicia of nonobviousness weigh heavily in favor of
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`non-obviousness. The IRA encoding and decoding methods and systems described
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`and claimed in the ’781 patent were a groundbreaking development in the field of
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`-4-
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`

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`coding theory. The invention overcame longstanding issues with previously
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`known error correcting codes in a way that was unexpected, has been widely
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`praised since its introduction, and has experienced commercial success through
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`adoption in numerous information transmission standards.
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`For these reasons, all of the remaining grounds of challenge must be denied.
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`III. OVERVIEW OF THE ART AND CITED REFERENCES
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`Those familiar with the field of error-correction codes would have known
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`that modifying or constructing codes was a highly unpredictable endeavor. Since it
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`was effectively impossible to mathematically prove the performance of a code,
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`researchers were forced to engage in extensive trial-and-error and experimentation
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`to determine whether new codes led to an improvement. Even when improvements
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`occurred, the reasons for improved performance were typically not well-
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`understood. EX2004, ¶46. As Petitioner’s expert conceded during cross-
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`examination:
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`What you would really like to be able to do is a formal
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`mathematical analysis of the strength of the codes that
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`you are working with, but that’s often really hard. So
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`often what the engineers in particular would do is … take
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`a variety of different [codes], run simulations and … then
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`I will get a general sense of what the [mathematical]
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`analysis would have shown me. … [I]t might even be
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`impossible to do the mathematical analysis.
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`-5-
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`

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`EX2033 at 256:21-257:12 (emphasis added). Caltech’s expert, Dr. Mitzenmacher,
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`likewise explains that discoveries had to be made via guesswork and
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`experimentation. EX2004, ¶46. As a result, it was rarely the case that a researcher
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`could reasonably predict that a particular modification would result in an
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`improvement in the performance of a code. Id.
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`Experiments showed that the performance of a code was highly dependent
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`on the specific properties and constraints of the code. These codes were not
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`viewed as interchangeable parts, where a property of a performant code could
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`simply be incorporated into other codes to improve them. Instead, the results
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`showed that the resulting code could end up being non-functioning. Id.
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`One example of the unpredictability of error-correction codes is illustrated in
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`the discovery of the classes of codes found in the cited prior art references: turbo
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`codes and low-density parity check (“LDPC” or Gallager) codes. Turbo codes
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`were discovered by Claude Berrou in 1993, and his discovery was met with
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`extreme skepticism because he could not explain why his code performed. Many
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`who attended his presentation believed he had made an error in his initial
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`experiments. It was not until after his results could be independently confirmed,
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`research and use of his turbo codes became widespread. (EX2004, ¶¶47-51)
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`LDPC codes, which are often viewed as a competitor to turbo codes, also
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`had a modest beginning. LDPC codes were first discovered by Dr. Robert
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`-6-
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`

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`Gallager in 1960, but largely remained ignored for over 35 years. The later
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`discovery of high-performance of these codes was surprising to those skilled in the
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`art. Dr. Gallager himself explains the unpredictability of this field with regard to
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`his code, “I had a little bit of an inkling [they could be good], but I also had a
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`suspicion that they well might not be. And I spent a long time trying to resolve
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`whether they were or not.” (EX2004, ¶¶52-56)
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`A. MacKay (EX1002)
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`1. MacKay highlights the unpredictability in the field at the time and the
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`corresponding need for experimentation to identify functioning codes. MacKay
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`investigated performance of randomly generating low-density parity-check
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`matrices that were “irregular” in the sense that 1/12 of the columns had a weight of
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`nine, and the remaining 11/12 columns had
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`weight of 3. EX1002, Table 1; see also Fig. 2
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`(excerpt shown). MacKay randomly generated
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`several parity-check matrices using patterns
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`with the above constraints and according to a generalized Poisson distribution. See
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`e.g., EX1002, p. 1451 (“The edges are placed ‘completely at random’…. We can
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`build parity check matrices by superposing random permutation matrices.”).
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`MacKay then ran simulations to test performance of the constructions. As noted
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`above, Dr. Davis explained that such experimentation was necessary because
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`-7-
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`

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`mathematical analysis would not have been able to reasonably predict whether the
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`constructions were performant. (EX2004, ¶57)
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`Based on the testing, MacKay evaluated the relative performance of the
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`constructions as divided into sub-classes (i.e., Poisson, sub-Poisson, super-Poisson
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`patterns) and reported that “super-Poisson” patterns performed better relative to
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`other sub-class patterns that were tested. MacKay noted that a number of the
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`randomly generated codes exhibited high error floors and had to be discarded.
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`EX1002, p. 1452 (“We discard the two codes with error floors…”). MacKay
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`explains that such error floors were the result of “cycles of length 4,” whose
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`avoidance “is not so easy to enforce in irregular Gallager codes with high weight
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`columns.” Id., p. 1454. See also, Id. p. 1449 (acknowledging that performance is
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`“sensitive to the distribution of column weights.”). MacKay did not provide any of
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`the actual codes used in its evaluation of Poisson sub-classes, either those that were
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`performant or those discarded due to high error floors. (EX2004, ¶58)
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`B.
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`Ping (EX1003)
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`The one-page article “Low density parity check codes with semi-random
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`parity check matrix” by Li Ping, W.K. Leung and Nam Phamdo describes a
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`method of improving on randomly generated parity check matrices, such as those
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`described by MacKay, by introducing specific non-random structural constraints to
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`a parity-check matrix. Ping explains that the encoding process for a randomly
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`-8-
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`

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`generated parity check matrices had several shortcomings, including that it was
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`“costly in terms of both memory and the operations involved.” EX1003, p. 38.
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`(EX2004, ¶59)
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`In light of such shortcomings, Ping identifies specific structural constraints
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`as a means of improving randomly generated parity check matrices. Ping instructs
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`that, first, the columns of the parity check matrix H be constructed as two
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`submatrices: submatrix Hp and submatrix Hd, each of which have a specifically
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`defined structure. Id. With regard to Hp, Ping assigns it a non-random,
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`deterministic form, where it is a square matrix populated as follows:
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`
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`With regard to Hd, Ping instructs that it be subdivided into “t equal sub-
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`blocks,” where t is “a preset integer constraints by (i) t divides n-k and (ii) n-k
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`divides kt.” (n is the length of the codeword and k is the number of information
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`bits.) Hd appears as follows:
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`For each of these sub-blocks, there is exactly “one element 1 per column and
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`kt/(n-k) 1s per row.” This means that the submatrix Hd has both uniform column
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`-9-
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`

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`and row weight, and the 1s are evenly distributed within the submatrix. Ping
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`explains that these constraints for Hd are necessary to the improved performance
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`sought because they “best increase the recurrence distance of each bit in the
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`encoding chain … and, intuitively, reduc[ing] the correlation during the decoding
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`process.” Id. In other words, Ping specifically identifies even distribution of 1s for
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`Hd in Ping’s code as enabling the better decoding performance compared to the
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`randomly generated matrices as in MacKay. See also, id., p. 39 (“Conclusion: It
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`has been shown that a semi-random approach to LDPC code design can achieve
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`essentially the same performance as the existing method with considerably reduced
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`complexity.”) (EX2004, ¶¶60-63)
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`IV. WEIGHT TO BE GIVEN RESPECTIVE EXPERT TESTIMONY
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`A. Dr. Davis’s testimony includes basic errors demonstrating a lack
`of credibility
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`Basic technical errors are an important clue to witness credibility. See, e.g.,
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`Merck & Co. v. Teva Pharm. USA, Inc., 347 F.3d 1367, 1371 (Fed. Cir. 2003)
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`(holding pharmaceutical testimony of a chemist to be less credible compared to the
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`testimony of pharmacologists and noting chemist made errors that those in the art
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`would have considered basic). In Merck, the chemist testified that an acid is not a
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`salt, which may be true generally in chemistry, but was not consistent with the
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`pharmaceutical usage. 347 F.3d at 1371. Here, Dr. Davis could not answer basic
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`questions about Berrou, the seminal paper on turbo codes, without rereading the
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`-10-
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`

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`entire article. EX2033, 54:17-60:3. He could not give an opinion on what
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`“irregular” meant in the field, and implied such information was unhelpful or
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`extraneous to the Board. Id., 87:7-89:16.
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`While the Frey reference is not at issue in this IPR a primary reference in
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`IPR2017-00210, the shallow analysis of this reference and basic errors illustrate
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`the need for considerable pause in crediting Dr. Davis’ testimony regarding any
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`cited art. In his testimony on Frey, he did not consider Frey's puncturing of parity
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`bits despite Frey’s teaching puncturing as a necessity to keep the overall rate of the
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`code constant. Id., 148:5-14; 150:3-10. Dr. Davis also displayed a curious lack of
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`knowledge regarding Frey’s discussion of its error floor, mistakenly thinking Frey
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`used the term “flattening effect” to refer to the top flat portion of the regular code's
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`graph. Id., 162:20-163:8. When asked about Frey’s “flattening effect,” he thought
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`it referred to the top flat portion of the regular code's graph, even though Frey
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`clearly says “the flattening effect for the … irregular turbo code … occurs at a
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`higher BER than it does for the regular turbo code.” Id., 165:3-166:18; see also
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`EX2030. Moreover, he testified as to his belief that Frey’s Figure 2 does not
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`depict parity bits in its bottom row of nodes despite Frey teaching exactly the
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`opposite. Compare id. at 112:9-12 (“[N]one of those [nodes] would be considered
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`parity bits.”) with EX1110 at 2 (describing “connecting each parity bit to a degree
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`1 codeword bit”).
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`-11-
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`

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`With regard to Ping and MacKay, Dr. Davis inaccurately testified that
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`MacKay’s “super-Poisson” pattern was consistent with Ping’s teaching of
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`“increas[ing] the recurrence distance.” EX1003, p. 38. Ping teaches that it made
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`its Hd sub-matrix regular and uniform in order to “best increase the recurrence
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`distance of each bit in the encoding chain.” Id. Dr. Davis correctly describes this
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`as “spread[ing] your 1s around” in the Hd sub-matrix. EX2033, 233:7. Yet he
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`incorrectly testified that “MacKay teaches in this same direction, when he is
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`talking about sub-Poisson, super-Poisson, Poisson ways of constructing parity
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`check matrices.” Id., 233:14-17. MacKay actually teaches the opposite. As
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`explained in further detail below and by Dr. Mitzenmacher, MacKay teaches that
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`its superior “super-Poisson constructions” have “high weight columns per row
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`[with] greater variance” (EX1002, p. 1451)—in other words, the 1s in MacKay’s
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`super-Poisson construction are more clustered rather than spread out as Ping
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`requires. See infra, Section V.E; EX2004, ¶128.
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`His unfamiliarity with the actual teachings of cited references, as well as
`
`with the actual knowledge in the relevant art, compels him to use hindsight to
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`define irregularity in terms of Caltech’s claims. The testimony of Dr. Davis should
`
`be discounted accordingly.3
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`3 Dr. Davis’s errors and unfamiliarity with the key references should also be
`
`considered in view of his admission that none of his publications related to repeat-
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`-12-
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`

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`B. Dr. Davis’s testimony is not independent
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`While the petition and expert declaration are expected to be consistent,
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`expert testimony that simply tracks and repeats the petition is entitled to little
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`weight. Wowza Media Sys., LLC v. Adobe Sys., Inc., IPR2013-00054, Paper 16, 4
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`(2013). Here, the petition and the Davis declaration show striking similarity,
`
`including the same language. For example, the sections discussing Ground 1 are
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`nearly identical. Compare Pet., 32-48, with EX1024, ¶¶86-134. In addition,
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`significant portions of Dr. Davis’s declaration were copied wholesale from Dr.
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`Frey’s unsworn expert report in a completely different litigation proceeding and
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`produced nearly two years prior to Dr. Davis’s declaration in this case. See
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`EX1024, ¶¶ 22-45. This significantly undercuts the independence and objectivity
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`of Dr. Davis’s testimony.
`
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`accumulate codes, low-density parity-check codes, turbo codes, or irregular codes
`
`in general. EX2033, 27:4-28:9. Perhaps unsurprisingly, he also testified that he
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`never attended the Allerton Conference on Communication, Control and
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`Computing because “the work that I do in coding theory wasn’t being presented at
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`that conference.” Id., 32:14-22.
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`-13-
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`

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`C. Dr. Davis’s evasiveness during his deposition undermines his
`credibility
`
`In 10X Genomics, Inc. v. Univ. of Chicago, the Board explained that expert
`
`evasiveness or unresponsiveness during cross examination would reduce the
`
`weight of the expert’s direct testimony. IPR2015-01157, Paper 30, 2 (2016). In this
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`regard, it is instructive how often Dr. Davis evaded straightforward questions about
`
`the art that an artisan of the time should have been able to give straightforward
`
`answers. For example, he evaded questions on whether Berrou’s Figure 5 showed a
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`relationship between bit error rate and signal-to-noise ratio despite the axes being
`
`clearly labeled as such. Id., 56:19-57:6, 58:19-59:3.
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`Regarding “irregular,” a key term in this trial, he evaded answering whether
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`his definition of irregular was the conventional meaning of “irregular” as generally
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`used in the field of error correction codes. Id., 66:10-68:4. He evaded answering
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`where the prior art provided a definition of “irregular” that was the same as his
`
`definition. Id., 72:17-75:18. He avoided answering what definition of “irregular”
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`he would use in the field of error correction codes generally. Id., 78:18-81:12. He
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`avoided answering whether his definition of “irregular” was consistent with the
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`definition used with Tanner graphs. Id., 83:21-87:6. His unresponsiveness during
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`cross-examination on this pivotal term is striking and warrants little or no weight
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`for his direct testimony.
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`-14-
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`

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`Other striking instances of evasiveness include his unresponsive for seven
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`pages of transcript regarding the simple question of whether puncturing would lead
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`to a lower rate relative to a code without puncturing (Frey states puncturing is
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`critical for rate reduction). Id., 152:12-159:14. He avoided answering where
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`MacKay expressly discloses irregular repetition of information bits (it does not).
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`Id., 249:2-251:21. Finally, he was evasive on the self-evident question of whether
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`Ping depicts a Tanner graph (it does not). Id., 269:21-272:12.
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`The contrast between cross-examination and redirect is also striking.
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`Redirect occurred after a break during which Dr. Davis had a “discussion about the
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`substance of the testimony and the general nature of the redirect” with Apple’s
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`counsel. Id., 275:9-13. This discussion enabled Dr. Davis to be far more responsive
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`and direct for Apple’s counsel. This witness behavior is precisely the sort of
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`behavior the Board has condemned in decisions like 10X Genomics. These
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`shenanigans are inimical to the efficiency of Board proceedings and the integrity of
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`the patent system. The appropriate response is to accord little or no weight to the
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`direct and redirect testimony of Dr. Davis.
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`V. GROUND 1: PING IN VIEW OF MACKAY DOES NOT RENDER
`CLAIMS 13-15, 18 AND 22 OBVIOUS
`
`The petition fails to demonstrate that claims 13-15, 18 and 22 would have
`
`been obvious in view of the combination of Ping and MacKay for at least the
`
`following reasons. First, the Petition fails to demonstrate that Ping and MacKay
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`-15-
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`

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`teach information bits in a variable number of subsets. Second, the petition fails to
`
`establish that a person of ordinary skill in the art would have been motivated by
`
`MacKay to incorporate non-uniform weights into Ping’s sub-matrix because
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`MacKay’s teachings are only applicable to full parity check matrices and Ping’s
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`full parity check matrix is already as non-uniform as MacKay’s irregular codes.
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`And Ping expressly teaches modifying the random codes of the type disclosed in
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`MacKay so as to impart the specific structure the proposed modification seeks to
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`destroy. Third, the petition’s proposed modification is not taught anywhere in
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`MacKay. Fourth, the petition’s proposed modification lacks enough specificity for
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`a person of ordinary skill in the art to make. Finally, the petition never discusses
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`whether its proposed combination would have any reasonable expectation of
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`succeeding, a requirement when proving obviousness. For these reasons, Ground 1
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`should be rejected. (EX2004, ¶¶67-132)
`
`A. Legal Principles
`
`In order to establish that a patent claim is obvious under 35 U.S.C. § 103,
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`one must first determine (1) the scope of the prior art, (2) differences between the
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`prior art and the claims at issue, and (3) the level of ordinary skill in the art—
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`“Against this background, the obviousness or nonobviousness of the subject matter
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`is determined,” with additional “secondary considerations” given to certain indicia
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`of nonobviousness. KSR Intern. Co. v. Teleflex Inc., 550 U.S. 398, 404 (2007)
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`-16-
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`(citing Graham v. John Deere Co., 383 U.S. 1, 17-18 (1950)). Those challenging a
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`claim must provide some articulated reasoning that includes identifying “a reason
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`that would have prompted a person of ordinary skill in the relevant field to
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`combine the elements in the way the claimed new invention does.” Id.
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`Importantly, it is also a petitioner’s burden to show that at the time of the
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`invention there was a “reasonable expectation of success” for the proposed
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`combination. Intelligent Bio-Sys. v. Illumina Cambridge, 821 F.3d 1359, 1367-68
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`(Fed. Cir. 2016) (challenger’s “burden to demonstrate both that a skilled artisan
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`would have been motivated to combine the teachings of the prior art references to
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`achieve the claimed invention, and that the skilled artisan would have had a
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`reasonable expectation of success in doing so.”); see also DePuy Spine, Inc. v.
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`Medtronic Sofamor Danek, Inc., 567 F.3d 1314, 1326 (Fed.Cir.2009) (“Although
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`predictability is a touchstone of obviousness, the ‘predictable result’ discussed in
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`KSR refers not only to the expectation that prior art elements are capable of being
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`physically combined, but also that the combination would have worked for its
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`intended purpose.”); MPEP § 2143.2.I (“Obviousness requires a reasonable
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`expectation of success”). Thus, merely identifying elements in the prior art is not
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`sufficient to establish obviousness—a person of ordinary skill in the art must have
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`reasonably expected that the combination would have succeeded for its intended
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`purpose.
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`Based on these principles, the Board must deny obviousness challenges
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`when a petitioner, as is the case here, fails to explain or provide evidence as to how
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`the proposed combination would predictably result in the improvement that
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`allegedly motivated the combination. See, e.g., JTEKT Corp. v. GKN Automotive,
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`Ltd., IPR2016-00046, Paper No. 27 at 28-29 (Jan. 23, 2017).
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`B.
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`The Petition fails to establish that either Ping or MacKay discloses
`information bits in a variable number of subsets
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`Claim 13 (and its challenged dependent claims 14-16 and 18) requires that
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`“the information bits appear in a variable number of subsets.” Similarly, claim 22
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`requires that “the information bits in the collection appear in a variable number of
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`subsets.” These limitations refer to the requirement that some information bits
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`appear in a different number of subsets (that are summed) than other information
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`bits, and reflect the “irregular repeat” step in IRA codes. Ground 1 should fail for
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`the simple fact that the petition does not establish that either reference discloses
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`these limitations. (EX2004, ¶¶71-80)
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`The petition acknowledges that Ping fails to disclose these limitations. See,
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`e.g., Pet. 32 (“Ping’s outer code is regular because, in Ping, each information bit
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`contributes to the same number of summations ….”). (EX2004, ¶72)
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`Similarly, the Petition fails to show where MacKay discloses that
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`information bits appear in a variable number of subsets. Rather than identify any
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`such limitation in MacKay, the petition relies on hindsight to read such a teaching
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`-18-
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`into MacKay. First, the petition refers to MacKay’s findings regarding irregular
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`Gallager codes (a distinct class of codes different from the coding methods claims
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`in the ’781 patent), which conclude that the best known Gallager codes “are
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`irregular codes whose parity check matrices have nonuniform weight per column.”
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`Pet. 40. Second, the petition asserts, without support, that the column weights in
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`MacKay’s parity-check matrix “represent the number of subsets in which [an]
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`information bit appears.” Id. But the columns in MacKay’s parity check matrices
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`correspond to both information bits and parity bits. Petitioner does not contend
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`otherwise. Nor does Petitioner identify any teaching in MacKay to apply nonequal
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`column weights to the information bits specifically. To the contrary, MacKay’s
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`irregularity is applied to the entire parity check matrix and the Petition’s citations
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`are silent as to whether information bits have regular or irregular column weights.
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`Accordingly, Petition fails to show how MacKay discloses the “information bits in
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`a variable number of subsets” limitation. (EX2004, ¶¶73-74)
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`As the petition itself recognizes, a parity check matrix reflects a relationship
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`between codeword bits and parity check equations, not information bits. Pet. 13
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`(“Using a parity-check matrix, a given vector x is a valid codeword if and only if
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`Hx = 0.”). Codeword bits are the output of the encoder, whereas information bits
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`are the input to the encoder. See Pet. 5 (“[A]n encoder … outputs a sequence of
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`encoded bits (or data elements) called a codeword.”). The Petition’s citations to
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`-19-
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`MacKay’s parit