`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`———————
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`———————
`
`
`
`APPLE INC.,
`Petitioner,
`
`v.
`
`Saint Lawrence Communications LLC,
`Patent Owner
`
`———————
`
`
`
`PETITION FOR INTER PARTES REVIEW
`
`OF
`
`U.S. PATENT NO. 6,807,524
`
`
`
`
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`
`I.
`INTRODUCTION ............................................................................................. 4
`II. MANDATORY NOTICES ............................................................................... 5
`A. Real Party-in-Interest................................................................................ 5
`B. Related Matters ......................................................................................... 5
`C. Lead and Back-up Counsel and Service Information .............................. 6
`III. GROUNDS FOR STANDING .......................................................................... 6
`IV. RELIEF REQUESTED ..................................................................................... 6
`V. THE REASONS FOR THE REQUESTED RELIEF ........................................ 7
`A. State of the Art before the ’524 Patent ..................................................... 7
`1. CELP Encoding and Decoding ........................................................ 7
`2.
`Signal Pre-Emphasis ........................................................................ 8
`3.
`Perceptual Weighting ..................................................................... 10
`B. The ’524 Patent – Overview ................................................................... 12
`C.
`Identification of Challenges ................................................................... 14
`1. Challenged Claims ......................................................................... 14
`2.
`Statutory Ground for Challenges ................................................... 14
`3. Level of Ordinary Skill in the Art .................................................. 15
`4. Claim Construction ........................................................................ 15
`i.
`“pitch codebook search device responsive to said perceptually
`weighted signal for producing pitch codebook parameters and
`an innovative search target vector” ......................................... 16
`“innovative codebook search device, responsive to said
`synthesis filter coefficients and to said innovative search target
`vector, for producing innovative codebook parameters” ........ 17
`iii. “signal forming device for producing an encoded wideband
`speech signal” ......................................................................... 17
`iv. “wideband [speech] signal” .................................................... 18
`v.
`“fixed denominator” ................................................................ 19
`Identification of How the Claims Are Unpatentable ..................... 19
`i.
`Challenge #1: Claims 1, 8, 15, 29, and 36 are invalid under 35
`U.S.C. § 103 over Salami in view of Kroon ........................... 19
`– 2 –
`
`ii.
`
`5.
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`
`
`ii. Challenge #2: Claims 2-3, 9-10, 16-17, 30-31, and 37-38 are
`invalid under 35 U.S.C. § 103 over Salami in view of Kroon
`and Makamura ........................................................................ 47
`iii. Challenge #3: Claims 6, 13, 20, 34, and 41 are invalid under
`35 U.S.C. § 103 over Salami in view of Kroon, Lim, and ’524
`APA ......................................................................................... 55
`iv. Challenge #4: Claims 4-5, 7, 11-12, 14, 18-19, 21, 32-33, 35,
`39-40, and 42 are invalid under 35 U.S.C. § 103 over Salami
`in view of Kroon, Lim, ’524 APA, and Makamura ................ 66
`VI. CONCLUSION ................................................................................................74
`
`
`
`– 3 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`I.
`
`INTRODUCTION
`U.S. Patent No. 6,807,524 (“the ’524 Patent,” Ex-1001) describes
`
`perceptually weighting speech signals during encoding. Specifically, the claims of
`
`the ’524 Patent are based upon the well-known techniques of: (i) code excited
`
`linear prediction, and (ii) signal frequency shaping via pre-emphasis and perceptual
`
`weighting. Notably, it was known before the ’524 Patent to apply CELP and
`
`frequency shaping techniques such as pre-emphasis and perceptual weighting
`
`together to speech signals. Further, it was known to separately control perceptual-
`
`related characteristics such as tilt and formant weighting by separate control
`
`parameters and terms in the transfer equations of filters, as well as to select various
`
`parameter values or transfer function equations, to optimize computational
`
`efficiency. While this field uses technical terms and math equations that create an
`
`appearance of complexity, the ’524 Patent is directed to a straight-forward and
`
`well-known solution to pre-emphasizing and perceptually weighting an encoded
`
`speech signal.
`
`This petition demonstrates that claims 1-21 and 29-42 of the ’524 Patent are
`
`unpatentable under pre-AIA 35 U.S.C. § 103. Accordingly, Apple Inc.
`
`(“Petitioner”) respectfully requests that claims 1-21 and 29-42 of the ’524 Patent
`
`be held invalid and cancelled.
`
`
`
`
`
`– 4 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`II. MANDATORY NOTICES
`A. Real Party-in-Interest
`The real party-in-interest is Apple Inc.
`
`B. Related Matters
`As of the filing date of this petition, the ’524 Patent has been asserted in:
`
` HTC Corp., et al. v. Acacia Research Corp., 2:15-cv-01510 (E.D. Tex.
`
`2015), terminated;
`
` Saint Lawrence Communications LLC v. LG Electronics, Inc., et al., 2:14-
`
`cv-01055 (E.D. Tex. 2014), terminated;
`
` Saint Lawrence Communications LLC v. Sony Mobile Communications
`
`(USA) Inc., et al., 2:15-cv-00350 (E.D. Tex. 2015), terminated;
`
` Saint Lawrence Communications LLC v. Samsung Electronics Co. Ltd., et
`
`al., 2:14-cv-00293 (E.D. Tex. 2014), terminated;
`
` Saint Lawrence Communications LLC v. HTC Corp., et al., 2:15-cv-00919
`
`(E.D. Tex. 2015), terminated;
`
` HTC Corp., et al. v. Acacia Research Corp., 8:15-cv-00378 (C.D. Cal.
`
`2015), terminated;
`
` Saint Lawrence Communications LLC v. Motorola Mobility LLC, 2:15-cv-
`
`00351 (E.D. Tex. 2015), ongoing;
`
` Saint Lawrence Communications LLC v. ZTE Corp., et al., 2:16-cv-00349
`
`(E.D. Tex. 2015), ongoing; and
`
`– 5 –
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
` Saint Lawrence Communications LLC v. Apple Inc., et al., 2:16-cv-00082
`
`(E.D. Tex. 2016), ongoing.
`
`C. Lead and Back-up Counsel and Service Information
`Lead Counsel
`
`Andrew S. Ehmke
`Phone: (214) 651-5116
`HAYNES AND BOONE, LLP
`Fax: (214) 200-0853
`2323 Victory Ave. Suite 700
`andy.ehmke.ipr@haynesboone.com
`Dallas, TX 75219
`USPTO Reg. No. 50,271
`
`Back-up Counsel
`Scott T. Jarratt
`HAYNES AND BOONE, LLP
`2323 Victory Ave. Suite 700
`Dallas, TX 75219
`
`Phone: (972) 739-8663
`Fax: (214) 200-0853
`scott.jarratt.ipr@haynesboone.com
`USPTO Reg. No. 70,297
`
`
`
`Please address all correspondence to lead and back-up counsel. Petitioner
`
`
`
`consents to electronic service via email.
`
`III. GROUNDS FOR STANDING
`Petitioner certifies that the ’524 Patent is eligible for inter partes review and
`
`that Petitioner is not barred or estopped from requesting inter partes review
`
`challenging the patent claims on the grounds identified in this petition. Petitioner
`
`was served with a complaint asserting infringement of the ’524 Patent on April 13,
`
`2016 (see Ex-1020), which is not more than one year before the filing of this
`
`Petition. Petitioner has not filed a civil action challenging the validity of any claim
`
`of the ’524 Patent.
`
`IV. RELIEF REQUESTED
`Petitioner asks that the Patent Trial and Appeal Board (“the Board”) review
`
`
`
`– 6 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`the accompanying prior art and analysis, institute a trial for inter partes review of
`
`claims 1-21 and 29-42 of the ’524 Patent, and cancel those claims as invalid.
`
`V. THE REASONS FOR THE REQUESTED RELIEF
`The concepts described and claimed in the ’524 Patent were neither novel
`
`nor non-obvious. Ex-1003. This petition, supported by the declaration of
`
`Petitioner’s expert Dr. Jordan Cohen, explains where each element of claims 1-21
`
`and 29-42 exists in the prior art and why the claims would have been obvious to a
`
`person of ordinary skill in the art (“POSITA”) before the earliest claimed priority
`
`date of the ’524 Patent. The full statement of the reasons for the relief requested is
`
`as follows.
`
`A.
`
`State of the Art before the ’524 Patent
`CELP Encoding and Decoding
`1.
`The ’524 Patent applies to the field of transmitting speech over a
`
`communication channel. To transmit speech, an encoder seeks to reduce the
`
`number of bits in a digitized speech signal, while balancing the trade-off of
`
`maintaining speech quality. Ex. 1003, ¶¶ 32-42. A known technique achieving a
`
`good trade-off between synthesized speech quality and bitrate is code excited
`
`linear prediction (“CELP”).
`
`In CELP, the speech signal can be reduced to three primary sets of
`
`parameters that are transmitted to the receiver: the linear prediction (“LP”) filter
`
`coefficients, the pitch codebook parameters (pitch lag and pitch gain), and the
`
`
`
`– 7 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`innovative codebook parameters (innovative codebook index and innovative
`
`codebook gain). Ex. 1003, ¶¶ 38-42. To obtain these parameters, the original
`
`speech signal is broken into 10–30 millisecond blocks called “frames” and 4–10
`
`millisecond “subframes.” For each subframe, pitch and innovative codebook
`
`parameters are calculated from the original speech signal; then, the LP filter
`
`coefficients, pitch codebook parameters, and innovative codebook parameters are
`
`transmitted to the receiver in a bitstream. Id.
`
`At the receiver, a decoder creates a synthesized speech signal using the
`
`parameters recovered from the incoming bitstream. Ex. 1003, ¶¶ 36-42. The
`
`innovative and pitch codebook parameters are used to identify the corresponding
`
`innovative codevector and pitch codevector from the innovative codebook and
`
`pitch codebook. Id. The two codevectors are combined to form an excitation
`
`signal that is filtered through the synthesis filter to produce a synthesized speech
`
`signal. Id.
`
`At the time of the ’524 Patent, speech coding techniques including pre-
`
`emphasis and perceptual weighting had been used in conjunction with CELP for
`
`both telephone band (200–3400 Hz) and wideband (50–7000 Hz) applications. Ex-
`
`1001, 2:9-16.
`
`Signal Pre-Emphasis
`2.
`It was known in the prior art to filter an input speech signal through a filter
`
`
`
`– 8 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`that boosts or “pre-emphasizes” a signal’s high-frequency content. Ex-1003, ¶¶
`
`43-48. Pre-emphasizing a signal’s high-frequency content decreases the overall
`
`spectral tilt and dynamic range of the signal. Ex-1008, 448; Ex-1047, 1565. For
`
`example, Fig. 2 of Dr. Cohen’s declaration provided below illustrates that for
`
`voiced speech, there is a wide dynamic range and negative spectral tilt, which are
`
`both decreased by boosting the high-frequency content. Ex-1003, Fig. 2. A
`
`reduced dynamic range is beneficial at the synthesis filter calculation stage because
`
`the recursion-equation calculations use fewer bits, and can be implemented using
`
`lower-cost chips. Ex-1024, 103.
`
`Dynamic
`Range
`
`Spectral Tilt
`
`Ex-1003, Fig. 2
`
`
`
`
`
`
`
`– 9 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`A filter commonly used in the prior art for pre-emphasis is a simple first
`
`order, “single-zero” filter with the transfer function: P(z) = 1 – µz-1, which
`
`provides larger values of P(z) for higher frequencies, boosting the signal’s high-
`
`frequency content. Ex-1008, 448; Ex-1021, 2:53-65; Ex-1023, 3:3-13.
`
`While a reduced dynamic range aids the synthesis filter calculation, after the
`
`synthesis filter coefficients were calculated, it was known that the signal no longer
`
`needed to be pre-emphasized. Ex-1021, 3:11-20. In fact, the effect of pre-
`
`emphasis was known to be harmful after computing the LP coefficients, because
`
`boosting the high-frequencies also boosts the error of those frequencies, yielding
`
`excess high-frequency noise. Id.; Ex-1003, ¶¶ 46-48. It was a known solution to
`
`undo the effect of the pre-emphasis filter at the encoder side to minimize such
`
`error; and it was further known that such beneficial de-emphasis could be
`
`performed at the same time as perceptual weighting by including a term in the
`
`transfer function that is the inverse of the pre-emphasis filter. Ex-1021, 3:11-20.
`
`Perceptual Weighting
`3.
`Perceptual weighting includes redistributing signal processing errors in the
`
`frequency domain to minimize and mask the distorting effect of error. Ex-1028,
`
`615-16; Ex-1003, ¶¶ 49-53. The input audio speech signal generally contains
`
`formants (spectral peaks resulting from vocal tract resonances) and background
`
`noise between the formant peaks. Ex-1003, ¶¶ 34, 49-56. The formants of a
`
`
`
`– 10 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`speech signal are illustrated in the insert of Fig. 2 above. Ex-1003, Fig. 2.
`
`Formants greatly mask noise by virtue of their large energy concentration at the
`
`frequencies surrounding the formant peaks. Id.
`
`A perceptual weighting filter emphasizes the formants by filtering the
`
`speech signal through a transfer function based on the signal’s LP coefficients. Id.
`
`Different forms of perceptual weighting filter transfer functions had been studied
`
`prior to the ’524 Patent. For example, a generalized perceptual-weighting filter
`
`transfer function with two perceptual weighting coefficients, γ1 and γ2, may take
`
`the form: W(z)=A(z/γ1)
`A(z/γ2), where 0≤γ2<γ1≤1. Ex-1022, 5:12-18; see also
`
`Ex-1028, 615-16 (one weighting coefficient).
`
`Various other equations for a speech filter transfer function—which can be
`
`adapted as a perceptual weighting filter simply by including weighting factor(s)—
`
`were also known. See Ex-1014, 1589. For instance, the Lim reference (Ex-1014)
`
`discloses the pole-zero transfer function: V(z)= ∑
`bkz−k
`qk=0
`1− ∑
`akz−k
`pk=1
`see also Ex-1025, 4 (H(z)= B(z)A(z)=
`); Ex-1033, 2 (H(z)= B(z)A(z)=
`B(z)
`1 + ∑
`aiz−1
`Ki=1
` b0 + b1z−1 + … + bpz−p
`a0 + a1z−1 + … + apz−p).
`
`. Ex-1014, 1597-98;
`
`Additionally, it was known to fix the denominator of the perceptual
`
`weighting filter with respect to time to increase computational efficiency (Ex-
`
`
`
`– 11 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`1005; Ex-1041), as well as to multiply the perceptual weighting filter W(z) by a tilt
`
`filter T(z), in the absence of a pre-emphasis filter, for controlling spectral tilt (Ex-
`
`1022, 1:64-2:17; cf. Ex-1024, 103).
`
`B.
`
`The ’524 Patent – Overview
`The ’524 Patent addresses difficulties that may arise in applying “telephone-
`
`band optimized CELP model to wideband signals.” Ex-1001, 2:15-64. One
`
`difficulty is that the prior art perceptual weighting filter W(z)= A(z/g1)
`A(z/g2), 0 < Γ2 <
`
`Γ1 ≤ 1 “has inherent limitations in modeling the formant structure and the required
`
`spectral tilt concurrently.” Id., 2:31-55.
`
`The ’524 Patent suggests that one way to address this issue is through a
`
`purportedly novel method of using a “modified” perceptual weighting filter that
`
`“has a transfer function with [a] fixed denominator whereby weighting of the
`
`wideband signal in a formant region is substantially decoupled from a spectral tilt
`
`of that wideband signal.” Ex-1001, 2:59-3:21.
`
`However, the use of a perceptual weighting filter having a fixed
`
`denominator and decoupling control over spectral tilt from formant weighting was
`
`already well-known in the prior art. Moreover, the other limitations of claims 1
`
`and 15 directed to generic CELP elements are admitted as prior art by the ’524
`
`Patent.
`
`In particular, the ’524 Patent describes a CELP encoding technique
`
`
`
`– 12 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`including pre-emphasizing the high-frequency content of an input wideband speech
`
`signal. Ex-1001, 7:40-8:19. The pre-emphasized signal is (1) used to calculate LP
`
`coefficients and (2) filtered by a perceptual weighting filter with a fixed-
`
`denominator transfer function. The pitch and innovation parameters are
`
`subsequently found using the perceptually weighted signal. Id., 8:20-34, 8:59-
`
`9:39.
`
`The specification of the ’524 Patent acknowledges that various of its claim
`
`limitations were already known. For example, the “Brief description of the prior
`
`art” section of the ’524 Patent acknowledges that CELP-related claim limitations
`
`were prior art: “One of the best prior art techniques capable of achieving a good
`
`quality / bit rate trade-off is the so-called Code Excited Linear Prediction (CELP)
`
`technique.” Ex-1001, 1:41-43. The background section further explains that the
`
`LP filter and pitch and innovative parameters are calculated in order to obtain a
`
`synthesized speech signal that is closest to the original signal. Id., 1:43-2:8.
`
`Additionally, the specification’s background section states that in order to reduce
`
`the dynamic range, a known solution was to use a modified perceptual weighting
`
`filter and pre-emphasis techniques for boosting high-frequency content. Id., 2:15-
`
`30.
`
`Accordingly, the ’524 Patent states that the CELP, pre-emphasis, perceptual
`
`weighting, and tilt/weighting decoupling steps of the claims were known in the
`
`
`
`– 13 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`prior art—and the alleged improvement relates only to using a “modified”
`
`perceptual weighting filter having a fixed denominator. Id, 1:59-64. However,
`
`fixing the denominator of the perceptual weighing filter was clearly disclosed in
`
`the Kroon reference (Ex-1005) and the dependent-claim limitations were also
`
`known in the art (Ex-1014; Ex-1021), as detailed below.
`
`C.
`
`Identification of Challenges
`Challenged Claims
`1.
`Claims 1-21 and 29-42 of the ’524 Patent are challenged in this petition.
`
`Statutory Ground for Challenges
`2.
`Challenge #1: Claims 1, 8, 15, 29, and 36 are obvious under 35 U.S.C. §
`
`103 over “Real-time Implementation of a 9.6 kbit/s ACELP Wideband Speech
`
`Coder,” CONF. REC. IEEE GLOBECOM, 447-451 (Dec. 1992) to Salami et al.
`
`(“Salami,” Ex-1008), in view of “Regular-Pulse Excitation—A Novel Approach to
`
`Effective and Efficient Multipulse Coding of Speech,” IEEE TRANS. ACOUSTICS,
`
`SPEECH, AND SIG. PROC., 1054-63 (Oct. 1986) to Kroon et al. (“Kroon,” Ex-1005).
`
`Salami was published at least as of February 21, 1994 and is thus prior art at
`
`least under 35 U.S.C. § 102(b). Kroon was published at least as of April 1988 and
`
`is thus prior art at least under 35 U.S.C. § 102(b).
`
`Challenge #2: Claims 2-3, 9-10, 16-17, 30-31, and 37-38 are obvious under
`
`35 U.S.C. § 103 over Salami in view of Kroon and U.S. Patent No. 5,295,224 to
`
`Makamura et al. (“Makamura,” Ex-1021).
`
`
`
`– 14 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`Makamura issued on March 15, 1994 and is thus prior art at least under 35
`
`U.S.C. § 102(b).
`
`Challenge #3: Claims 6, 13, 20, 34, and 41 are obvious under 35 U.S.C. §
`
`103 over Salami in view of Kroon, “Enhancement and Bandwidth Compression of
`
`Noisy Speech,” PROC. IEEE, 1586-1604 (Dec. 1979) to J. S. Lim et al. (“Lim,” Ex-
`
`1014), and the Admitted Prior Art of the ’524 Patent (“’524 APA”).
`
`Lim was published at least as of 1980 and is thus prior art at least under 35
`
`U.S.C. § 102(b).
`
`Challenge #4: Claims 4-5, 7, 11-12, 14, 18-19, 21, 32-33, 35, 39-40, and 42
`
`are obvious under 35 U.S.C. § 103 over Salami in view of Kroon, Lim,’524 APA,
`
`and Makamura.
`
`Level of Ordinary Skill in the Art
`3.
`Based on the technologies disclosed in the ’524 Patent, the level of ordinary
`
`skill in the art would include someone who had, at the priority date of the ’524
`
`Patent, (i) a Master’s of Science (M.S.) degree in Electrical Engineering or
`
`equivalent training, and (ii) at least three to five years of relevant industry
`
`experience in the field of speech coding. Ex-1003, ¶¶ 24-26.
`
`Claim Construction
`4.
`This petition presents claim analysis in a manner that is consistent with the
`
`broadest reasonable construction in light of the specification. See 37 C.F.R. §
`
`42.100(b); In re Translogic Tech., Inc., 504 F.3d 1249, 1257 (Fed. Cir. 2007).
`– 15 –
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`i.
`
`“pitch codebook search device responsive to said perceptually
`weighted signal for producing pitch codebook parameters
`and an innovative search target vector”
`This term is found in claim 15. In the case St. Lawrence Comm. LLP v. ZTE
`
`Corp. et al., the U.S. District Court for the Eastern District of Texas (“ZTE-
`
`Court”) construed this term under 35 U.S.C. § 112(6). Ex-1019, 55-57. The ZTE-
`
`Court construed the function of this term to be “producing pitch codebook
`
`parameters and an innovative search target vector,” and the corresponding structure
`
`to be “a processor configured to find the parameters b, T and j which minimize the
`
`mean-squared error e(j) = ||x – b(j)y(j)||2 and configured such that x′ = x – byT, and
`
`equivalents thereof.”
`
`However, the ZTE-Court’s claim construction does not address or take into
`
`account other structures disclosed in the specification that perform the claimed
`
`function. For example, Fig. 1 and the associated discussion describe a processor
`
`configured to use an algorithm whereby a pitch module performs calculations
`
`using a looped search to bring about “producing pitch codebook parameters and an
`
`innovative search target vector.”
`
`This Petition adopts and applies the function and structure identified by the
`
`ZTE-Court, as well as the structures and algorithms disclosed in the ’524 Patent’s
`
`specification as discussed in the foregoing paragraphs.
`
`
`
`
`
`– 16 –
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`ii.
`
`“innovative codebook search device, responsive to said
`synthesis filter coefficients and to said innovative search
`target vector, for producing innovative codebook
`parameters”
`This term is found in claim 15. The ZTE-Court construed this term under
`
`35 U.S.C. § 112(6). Ex-1019, 57-59. The ZTE-Court construed the function of
`
`this term to be “producing innovative codebook parameters,” and the
`
`corresponding structure to be “a processor configured to find the optimum
`
`excitation codevector ck and gain g which minimize the mean-squared error E = ∥x′
`− gHck∥2, and equivalents thereof.”
`
`However, the ZTE-Court’s claim construction does not address or take into
`
`account the other structures disclosed in the specification. For example, Fig. 1 and
`
`the associated discussion describe a processor configured to use an algorithm
`
`whereby the output of a pitch module is used to perform calculations using an
`
`excitation vector search to bring about “producing innovative codebook
`
`parameters.”
`
`This Petition adopts and applies the function and structure identified by the
`
`ZTE-Court, as well as the structures and algorithms disclosed in the ’524 Patent’s
`
`specification as discussed in the foregoing paragraphs.
`
`iii.
`
`“signal forming device for producing an encoded wideband
`speech signal”
`This term is found in claim 15. The ZTE-Court construed this term under
`– 17 –
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
`
`35 U.S.C. § 112(6). Ex-1019, 59-61. The ZTE-Court construed the function of
`
`this term to be “producing an encoded wideband [speech] signal,” and the
`
`corresponding structure to be “a processor configured to multiplex the pitch
`
`codebook parameters T, b, and j, the innovation codebook parameters k and g, and
`
`the synthesis filter coefficients Â(z), and equivalents thereof.”
`
`However, the ZTE-Court’s claim construction does not address or take into
`
`account the other structures disclosed in the specification. For example, Fig. 1 and
`
`the associated discussion describe a processor configured to use an algorithm
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`whereby the pitch and innovation modules send signals to a multiplexer to bring
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`about “producing an encoded wideband [speech] signal.”
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`This Petition adopts and applies the function and structure identified by the
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`ZTE-Court, as well as the structures and algorithms disclosed in the ’524 Patent’s
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`specification as discussed in the foregoing paragraphs.
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` “wideband [speech] signal”
`iv.
`The ZTE-Court construed this term to mean “a [speech] signal that spans a
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`wider bandwidth than traditional telephone signals and that has a frequency range
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`of approximately 50–7000Hz.” Ex-1018, 107-113. In a separate case before the
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`U.S. District Court for the Eastern District of Texas, where the court has not yet
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`issued a Markman order, Apple proposed construing this term to mean “a speech
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`signal that spans a wider bandwidth than traditional telephone signals and that has
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`a frequency range of 50–7000 Hz sampled at 16000 samples/sec.” Ex-1018,
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`Appen. B, 1.
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`This petition adopts and applies the ZTE-Court’s construction of this term as
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`well as Apple’s proposed construction.
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`v. “fixed denominator”
`The above claim term is found in independent claims 1 and 8. From the
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`prosecution history of Bessette, a POSITA would understand that the claimed
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`“transfer function with fixed denominator” means that the transfer function’s
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`denominator is fixed with respect to the variable of time: “The denominator of the
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`perceptual weighting filter [] varies in time with the LP parameters ai and
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`accordingly is not fixed as required by claim 1.” Ex-1002 (January 23, 2004
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`Remarks in Reply to Examiner’s Non-Final Office Action, 7).
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`This petition adopts and applies the broadest reasonable interpretation of
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`“fixed denominator” in view of the specification, including at least: “the
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`denominator is fixed with respect to the variable of time.”
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`5.
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`Identification of How the Claims Are Unpatentable
`i. Challenge #1: Claims 1, 8, 15, 29, and 36 are invalid under 35
`U.S.C. § 103 over Salami in view of Kroon
`a)
`Summary of Salami
`
`
`Salami (Ex-1008) was cataloged and made publicly available in the Library
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`of Congress within a week after June 29, 1993 and at the Naval Academy Nimitz
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`Library no later than February 21, 1994. Ex-1017, ¶¶ 28-42. Accordingly, Salami
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`is prior art under pre-AIA §102(b).
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`Salami discloses real-time implementation of a wideband Algebraic-CELP
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`(“ACELP”) speech coder. Ex-1008, 447. In order to improve the LP analysis,
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`Salami uses pre-emphasis to boost high frequencies, thereby reducing the signal’s
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`dynamic range, via the pre-emphasis filter: P(z) = 1 – μz-1. Id., 448.
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`The LP coefficients are calculated based on the pre-emphasized signal, and
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`the pre-emphasized signal is perceptually weighted via a perceptual weighting
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`filter. Id., 448-49. The encoder disclosed in Salami decouples spectral tilt, which
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`is controlled by the pre-emphasis filter, from formant weighting, which is
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`separately controlled by the perceptual weighting filter. See id., 448.
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`Salami further discloses that the perceptually weighted signal is used in a
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`pitch codebook search to obtain pitch codebook parameters and an innovative
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`search target vector. Ex-1008, 448-50. The innovative search target vector and LP
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`coefficients are used in an innovative codebook search to obtain innovative
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`codebook parameters by minimizing the difference between the original signal and
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`the synthesized signal based on candidate innovative codebook vectors. Id. The
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`pitch and innovative codebook parameters and LP coefficients are multiplexed into
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`a signal and sent to the decoder. Id., Fig. 1, Table 2.
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`Salami further discloses a shaping matrix. Ex-1008, 449-50. The shaping
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`matrix is a type of perceptual weighting filter (having weighting factors and based
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`on the LP coefficients) that shapes/weights the innovative vectors of the algebraic
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`codebook by the transfer function: F(z)=(1−µz−1)A(z/γ1)
`A(z/γ2), which includes a
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`term proportional to the pre-emphasis filter. Id.
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`Salami therefore discloses each of the CELP-related limitations of the ’524
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`Patent’s claims. For example, CELP-related components of claims 1 and 15
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`include producing: a) synthesis filter coefficients; b) pitch codebook parameters;
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`c) innovative codebook parameters; and d) a multiplexed signal including those
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`coefficients and parameters. As illustrated in Fig. 3 below—an annotated
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`comparison of Fig. 1 of the ’524 Patent with Fig. 1 of Salami—Salami discloses
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`each of the CELP-related claim 1 and 15 elements a) through d) as they are
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`received at the receiver/decoder. Ex-1003, Fig. 3.
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`’524 Patent
`Fig. 1
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`a) Synth. Coeff. b) Pitch Parameters c) Innovative Parameters d) Muxed Parameters
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`Salami
`Fig. 1
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`
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`
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`Ex-1003, Fig. 3
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`However, Salami does not disclose fixing the denominator of the perceptual
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`weighting filter. Rather, Salami discloses that the denominator varies in time
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`proportional to the synthesis filter coefficients ai. As discussed below, a POSITA
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`would have understood that fixing the denominator was simply a design choice—
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`and replacing a dynamic denominator with a fixed one would have been a simple
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`substitution of a known element with another to obtain predictable results (e.g.,
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`balancing computational efficiency with short-time modeling). Ex-1003, ¶¶ 104-
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`113.
`
`Summary of Kroon
`b)
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`Kroon (Ex-1005) was cataloged and made publicly available in the Library
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`of Congress within a week after March 16, 1987 and no later than April 1988. Ex-
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`1017, ¶¶ 16-27. Accordingly, Kroon is prior art under pre-AIA §102(b).
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`Kroon discloses using LP speech coding techniques in the context of mobile
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`telephony and computer networks. Ex-1005, 1054. Kroon further discloses details
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`regarding regular-pulse excitation coding procedures and an algorithm for finding
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`excitation sequences. Ex-1005, 1054.
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`Additionally, Kroon discloses determining an excitation signal such that “the
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`perceptual error between the original and the reconstructed signal is minimized,”
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`where the computational effort is moderate and reduced by using a “fixed error
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`weighting filter, among other techniques.” Ex-1005, 1062. For example, Kroon
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`Petition for Inter Partes Review of U.S. Patent No. 6,807,524
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`discloses an error (perceptual) weighting filter of the form:
`
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`Ex-1005, 1060. In order to reduce the complexity of the coder without sacrificing
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`the quality of speech, the impulse response of the filter is made to be time invariant
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`(fixed). Ex-1005, 1059-62.
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`c)
` Reasons to Combine
`There are many reasons why a POSITA would combine Salami with the
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`teachings of Kroon. First, Salami’s coder and Kroon’s techniques are both
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`generally directed to LP coders that solve for the optimal synthesized speech signal
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`by calculating LP coefficients and the optimal excitation sequence. Salami and
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`Kroon are therefore directed at the same objective and same problem of solving for
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`the optimal synthesized signal via linear prediction in a perceptually weighted
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`domain, with the goal of minimizing the number of computations required.
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`Indeed, both Salami and Kroon cite to the same research groups and
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`researchers that also studied improving LP coding via perceptual weighting,
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`including the work of N. Jayant; also, Salami cites to a paper authored by Salami
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`himself and edited by B. Atal, while Kroon cites to a publication of B. Atal. Ex-
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`1008, 451; Ex-1005, 1063.
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`Second, before the ’524 Patent’s alleged effective filing date, there was a
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`Petition for Inter Partes Review