`
`Filed on behalf of Sony Electronics Inc.
`By: Gregory S. Gewirtz
`Russell W. Faegenburg
`LERNER DAVID LLP
`Telephone: 908.654.5000
`Facsimile: 908.654.7866
`Email: ggewirtz@lernerdavid.com
`rfaegenburg@lernerdavid.com
`litigation@lernerdavid.com
`
`Filed: June 30, 2023
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`_
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`_
`
`SONY ELECTRONICS INC.,
`Petitioner,
`
`v.
`
`JAWBONE INNOVATIONS, LLC,
`Patent Owner.
`
`IPR2023-01153
`U.S. Patent No. 11,122,357
`
`PETITION FOR INTER PARTES REVIEW OF
`CLAIMS 1-20 OF U.S. PATENT NO. 11,122,357
`
`
`
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`
`
`TABLE OF CONTENTS
`
`Page No.
`
`TABLE OF AUTHORITIES ....................................................................................... vi
`
`TABLE OF EXHIBITS ............................................................................................. viii
`
`INTRODUCTION ........................................................................................................ 1
`
`I.
`
`BACKGROUND ................................................................................................ 3
`
`A. Griffiths and Jim Publish Their Seminal GSC Article in 1982. ............... 3
`
`B. Over the Next Two Decades, the GSC was
`Used in Microphone Arrays to Reduce Noise. ........................................ 5
`
`C.
`
`D.
`
`Published in 2001, Brandstein Illustrates How to
`Use a GSC with a Microphone Array to Reduce Noise. .......................... 6
`
`Contemporaneously, Gannot Taught Adapting
`The GSC To Handle Arbitrary Transfer Functions. .............................. 10
`
`E.
`
`Other Concepts in the ’357 Patent Were Well Known. ......................... 12
`
`1.
`
`2.
`
`Filtering And Summing In The
`Time Domain Were Well Known. ............................................... 12
`
`Delaying Signals Based On Geometry To Adjust
`For Differences In Arrival Times Was Well Known. .................. 13
`
`II. THE ’357 PATENT .......................................................................................... 14
`
`A.
`
`The ’357 Patent Discloses Nothing Innovative. ..................................... 14
`
`1.
`
`2.
`
`The ’357 Patent Purports To Distinguish I
`tself From The Prior Art By Using A
`Virtual Microphone Designed To Capture
`Only Noise, Which Had Been Known For Decades. .................. 14
`
`The ’357 Patent Concedes It Relies
`on Known Techniques to Form Virtual
`Microphones from Physical Microphones................................... 15
`
`3.
`
`The ’357 Patent Discloses Formulas For The Purportedly
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`U.S. Patent No. 11,122,357
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`
`Innovative Set Of Virtual Microphones,
`But These Formulas Rely On Near-Field Design. ....................... 17
`
`B.
`
`C.
`
`The Claims Recite Generic Virtual
`Microphones And Generic Signal Processing. ...................................... 19
`
`The Claims Were Not Carefully
`Scrutinized During Prosecution ............................................................. 20
`
`III. STATEMENT OF RELIEF REQUESTED ...................................................... 21
`
`A. Grounds .................................................................................................. 21
`
`B.
`
`The Earliest Priority Date the ’
`357 Patent Claims Is June 13, 2007. ...................................................... 21
`
`C.
`
`The References Are Prior Art. ............................................................... 21
`
`D.
`
`The Asserted References Are Analogous Art. ....................................... 22
`
`IV. LEVEL OF ORDINARY SKILL ...................................................................... 22
`
`V. CLAIM CONSTRUCTION .............................................................................. 23
`
`VI. GROUNDS OF UNPATENTABILITY ........................................................... 23
`
`A. Ground 1: Brandstein and Gannot ......................................................... 23
`
`1.
`
`Claim 1 ......................................................................................... 23
`
`a.
`
`b.
`
`c.
`
`d.
`
`e.
`
`Preamble ............................................................................ 23
`
`First Virtual Microphone
`Comprising a Combination of Signals
`from First and Second Physical Microphones .................. 24
`
`Second Virtual Microphone .............................................. 26
`
`Substantially Similar Responses to Noise
`and Substantially Dissimilar Responses to Speech ........... 27
`
`A Signal Processor Operative to Combine
`Microphone Signals by Filtering and Summing
`in the Time Domain ........................................................... 29
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`
`f.
`
`g.
`
`Applying a Varying Linear Transfer Function .................. 31
`
`Generating an Output Signal with Reduced Noise ............ 33
`
`Claim 2 ......................................................................................... 35
`
`Claim 3 ......................................................................................... 35
`
`Claim 4 ......................................................................................... 36
`
`Claim 5 ......................................................................................... 39
`
`a.
`
`b.
`
`Claim 5 Encompasses Standard
`Near-Field Time-Alignment .............................................. 39
`
`Brandstein Discloses or Renders Obvious
`Standard Near-Field Time-Alignments for the GSC. ....... 40
`
`Claim 6 ......................................................................................... 46
`
`Claim 7 ......................................................................................... 49
`
`Claim 8 ......................................................................................... 49
`
`Claim 9 ......................................................................................... 49
`
`2.
`
`3.
`
`4.
`
`5.
`
`6.
`
`7.
`
`8.
`
`9.
`
`10. Claim 10 ....................................................................................... 50
`
`11. Claim 11 ....................................................................................... 51
`
`12. Claim 12 ....................................................................................... 52
`
`13. Claim 13 ....................................................................................... 53
`
`14. Claim 14 ....................................................................................... 55
`
`15. Claim 15 ....................................................................................... 56
`
`a.
`
`b.
`
`c.
`
`d.
`
`Preamble ............................................................................ 56
`
`First Virtual Microphone ................................................... 57
`
`Second Virtual Microphone .............................................. 57
`
`Substantially Similar Responses to Noise and
`Substantially Dissimilar Responses to Speech .................. 57
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`U.S. Patent No. 11,122,357
`
`
`e.
`
`f.
`
`g.
`
`h.
`
`Virtual Microphone Array with a Single Null .................. 58
`
`Signal Processor ................................................................ 59
`
`Applying a Varying Linear Transfer Function ................. 59
`
`Generating an Output Signal with Reduced Noise ............ 59
`
`16. Claim 16 ....................................................................................... 60
`
`17. Claim 17 ....................................................................................... 60
`
`18. Claim 18 ....................................................................................... 61
`
`19. Claim 19 ....................................................................................... 62
`
`20. Claim 20 ....................................................................................... 62
`
`B. Ground 2: Brandstein, Gannot, and Griffiths-Jim ................................. 62
`
`C. Ground 3: Brandstein, Gannot, and McCowan ...................................... 64
`
`VII. SECONDARY CONSIDERATIONS OF NONOBVIOUSNESS ................... 67
`
`VIII. DISCRETIONARY DENIAL UNDER
`§ 314(A) IS NOT APPROPRIATE. ................................................................. 68
`
`A.
`
`Co-Pending Litigation (Fintiv) ............................................................... 68
`
`1.
`
`2.
`
`3.
`
`4.
`
`5.
`
`6.
`
`Factor 1: Potential Stay ................................................................ 68
`
`Factor 2: Proximity of Trial to FWD ........................................... 69
`
`Factor 3: Investment in Parallel Proceeding ................................ 69
`
`Factor 4: Overlapping Issues ....................................................... 69
`
`Factor 5: The Parties .................................................................... 70
`
`Factor 6: Other Circumstances .................................................... 71
`
`B.
`
`Prior IPR Petitions (General Plastic) ..................................................... 72
`
`IX. DISCRETIONARY DENIAL UNDER
`§ 325(D) IS NOT APPROPRIATE. ................................................................. 73
`
`X. MANDATORY NOTICES ............................................................................... 74
`
`A.
`
`Real Parties-In-Interest (37 C.F.R. § 42.8(b)(1)) ................................... 74
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`U.S. Patent No. 11,122,357
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`
`B.
`
`C.
`
`Related Matters (37 C.F.R. § 42.8(b)(2)) ............................................... 74
`
`Lead and Backup Counsel (37 C.F.R. § 42.8(b)(3)) .............................. 75
`
`D.
`
`Service Information (37 C.F.R. § 42.8(b)(4)) ........................................ 75
`
`E.
`
`F.
`
`Payment of Fees (37 C.F.R. §42.103) .................................................... 75
`
`Grounds for Standing (37 C.F.R. §42.104(a)) ....................................... 76
`
`XI. CONCLUSION ................................................................................................. 76
`
`
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`IPR2023-01153
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`
`TABLE OF AUTHORITIES
`
`Page(s)
`
`CASES
`
`Apple, Inc. v. Fintiv,Inc.,
`IPR2020-00019, Paper 11 (P.T.A.B. Mar. 20, 2020) ................................... 68, 71
`
`Cal. Inst. of Tech. v. Broadcom Ltd.,
`25 F.4th 976 (Fed. Cir. 2022) ............................................................................. 70
`
`GAF Materials LLC v. Kirsch Rsch. & Dev., LLC,
`IPR2021-00192, Paper 14 (P.T.A.B. May 25, 2021) ......................................... 69
`
`Gen. Plastic Indus. Co. v. Canon Kabushiki Kaisha,
`IPR2016-01357, Paper 19 (P.T.A.B. Sept. 6, 2017) .......................................... 71
`
`Global Tel-Link Corp. v. HLFIP Holding, Inc.,
`IPR2021-00444, Paper 14 (P.T.A.B. July 22, 2021) .......................................... 69
`
`Google LLC v. Jawbone Innovations, LLC,
`IPR2022-00630, Paper 10 (P.T.A.B. Sept. 13, 2022) ........................................ 71
`
`In re GPAC Inc.,
`57 F.3d 1573 (Fed. Cir. 1995) ............................................................................ 22
`
`Huawei Techs. Co. v. WSOU Invs., LLC,
`IPR2021-00226, Paper 10 (P.T.A.B. June 10, 2021) ......................................... 70
`
`Kirsch Rsch. & Dev., LLC v. GAF Materials, LLC,
`No. 20-13683 (JMV), 2021 U.S. Dist. LEXIS 111667
`(D.N.J. June 15, 2021) ........................................................................................ 69
`
`KSR Int’l Co. v. Teleflex Inc.,
`550 U.S. 398 (2007) .................................................................................... passim
`
`Leapfrog Enters. v. Fisher-Price, Inc.,
`485 F.3d 1157 (Fed. Cir. 2007) .......................................................................... 67
`
`Mercedes-Benz USA, LLC v. Carucel Invs. L.P.,
`IPR2019-01404, Paper 12 (Jan. 22, 2020) ......................................................... 72
`
`NetNut Ltd. v. Bright Data Ltd.,
`IPR2021-00465, Paper 11 (P.T.A.B. Aug. 12, 2021) ........................................ 72
`
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`Newell Cos. v. Kenney Mfg. Co.,
`864 F.2d 757 (Fed. Cir. 1988) ............................................................................ 67
`
`Nidec Motor Corp. v. Zhongshan Broad Ocean Motor Co.,
`868 F.3d 1013 (Fed. Cir. 2017) .......................................................................... 23
`
`Samsung Elecs. Am. Inc. v. Snik LLC,
`IPR2020-01428, Paper 10 (P.T.A.B. Mar. 9, 2021) ........................................... 70
`
`Sand Revolution II, LLC v. Cont’l Intermodal Grp.-Trucking LLC,
`IPR2019-01393, Paper 24 (P.T.A.B. June 16, 2020) ......................................... 70
`
`Skechers U.S.A., Inc. v. Nike, Inc.,
`IPR2021-00160, Paper 10 (P.T.A.B. May 19, 2021) ......................................... 69
`
`Toshiba Am. Info. Sys., Inc. v. Walletex Microelecs. Ltd.,
`IPR2018-01538, Paper 11 (Mar. 5, 2019) .......................................................... 72
`
`Unwired Planet, LLC v. Google Inc.,
`841 F.3d 995 (Fed. Cir. 2016) ............................................................................ 22
`
`Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc.,
`200 F.3d 795 (Fed. Cir. 1999) ............................................................................ 23
`
`STATUTES, RULES & OTHER AUTHORITIES
`
`35 U.S.C. § 314(a) ................................................................................................... 68
`
`35 U.S.C. § 325(d) ................................................................................................... 73
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`
`
`
`
`Exhibit No.
`1001
`
`Description
`U.S. Patent No. 11,122,357 (“the ’357 patent”)
`
`TABLE OF EXHIBITS
`
`1002
`
`Declaration of Richard M. Stern, Ph.D.
`
`1003
`
`1004
`
`1005
`
`1006
`
`Excerpts of MICROPHONE ARRAYS: SIGNAL PROCESSING
`TECHNIQUES AND APPLICATIONS (Michael Brandstein & Darren
`Ward eds., Springer-Verlag 2001) (“Brandstein”)
`
`Sharon Gannot et al., Signal Enhancement Using Beamforming
`and Nonstationarity with Applications to Speech, vol. 49, no. 8
`IEEE TRANSACTIONS ON SIGNAL PROCESSING, 1614 (Aug.
`2001) (“Gannot”)
`
`Lloyd Griffiths & Charles Jim, An Alternative Approach to
`Linearly Constrained Adaptive Beamforming, vol. AP-30, no. 1
`IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 27 (Jan.
`1982) (“Griffiths-Jim”)
`
`Iain A. McCowan et al., Near-Field Adaptive Beamformer for
`Ro- bust Speech Recognition, vol. 12, no. 1 DIGITAL SIGNAL
`PRO- CESSING, 87 (Jan. 2002) (“McCowan”)
`
`1007
`
`U.S. Patent No. 5,651,071 (“Lindemann”)
`
`1008
`
`U.S. Patent No. 5,627,799 (“Hoshuyama”)
`
`1009
`
`U.S. Patent Publication No. 2003/0128848 (“Burnett ’848”)
`
`1010
`
`Excerpts from the ’357 patent’s file history
`
`1011
`
`U.S. Provisional Patent Application No. 61/045,377
`
`1012
`
`Curriculum Vitae of Richard M. Stern, Ph.D.
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`
`Exhibit No.
`
`Description
`
`1013
`
`Declaration of Carol S. Peterson
`
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`
`
`Petitioner Sony Electronics Inc. (“Petitioner” or “Sony”), requests inter partes
`
`review (“IPR”) of claims 1-20 of U.S. Patent 11,122,357, which Jawbone Innovations
`
`(“Patent Owner” or “PO”) purportedly owns.
`
`INTRODUCTION
`
`The challenged claims recite devices that process audio signals from
`
`microphones to reduce noise. The claimed devices comprise two “virtual”
`
`microphones, each formed by combining signals from two physical microphones. The
`
`two virtual microphones must have substantially similar responses to noise and
`
`substantially dissimilar responses to speech. But the claims do not require that the
`
`device do anything with the virtual microphones. Instead, the claims merely recite
`
`that
`
`the device must
`
`include a signal processor
`
`that performs generic
`
`signal-processing operations like filtering the physical-microphone signals, summing
`
`the physical-microphone signals, and applying a transfer function. The claims recite
`
`these conventional signal-processing operations only at a high level. For example, the
`
`claims do not elaborate on the filter to apply; they require only that some “filtering” of
`
`the physical-microphone signals occur.
`
`The two virtual microphones may be created by the recited filtering and
`
`summing of the physical-microphone signals. But as the ’357 patent concedes, that
`
`was a “common” technique for creating virtual microphones known to those skilled
`
`in the art. (Ex. 1001, 8:55-60.) The generic language of the claims contrasts with the
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`IPR2023-01153
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`
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`’357 patent specification, which identifies specific formulas defining the two virtual
`
`microphones that are the basis for the purported innovation. (Compare, e.g., id.
`
`claim 1 with id. 11:6-16, 12:20.)
`
`Untethered from the specification’s formulas, the claims’ recitation of generic
`
`signal-processing concepts encompasses prior art describing the Generalized Sidelobe
`
`Canceler (“GSC”), a fundamental noise-reduction technique introduced in the 1980s.
`
`Broadly applicable to many signal-processing applications, the GSC involves
`
`filtering and summing the signals from at least two sensors in different ways to produce
`
`two virtual sensors, one that captures the target signal plus noise and another that
`
`captures just noise. Subtracting the noise signal from the target-plus-noise signal
`
`cancels out the noise and yields a cleaner output signal.
`
`Years before the ’357 patent’s earliest possible priority date, a widely used
`
`reference book, MICROPHONE ARRAYS (Springer-Verlag 2001) (“Brandstein”),
`
`explained that it was common to use the GSC with a microphone array to reduce noise
`
`in speech-signal processing. Contemporaneously with Brandstein’s publication,
`
`Sharon Gannot and other researchers published in IEEE’s Transactions on Signal
`
`Processing an article
`
`titled Signal Enhancement Using Beamforming and
`
`Nonstationarity with Applications to Speech (“Gannot”), describing a generalized
`
`version of the GSC technique that would make it even more robust by handling
`
`arbitrary linear transfer functions. As its title indicates, Gannot likewise contemplated
`
`2
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`

`

`IPR2023-01153
`U.S. Patent No. 11,122,357
`
`reducing noise in speech applications. Together, Brandstein and Gannot disclose all
`
`the limitations of the ’357 patent’s claims and render all the claims obvious.
`
`Because they cover GSC techniques published years before the earliest priority
`
`date, claims 1-20 are unpatentable. The Board should cancel those claims.
`
`I.
`
`BACKGROUND
`
`When Patent Owner filed the ’357 patent’s priority applications in 2007,
`
`techniques for reducing noise in signals had been known for decades. One prominent
`
`technique was the Generalized Sidelobe Canceler, or GSC. In a nod to its inventors,
`
`the GSC is sometimes also called the Griffiths-Jim beamformer. (Ex. 1002 ¶30.)
`
`A. Griffiths and Jim Publish Their Seminal GSC Article in 1982.
`
`In 1982, Lloyd Griffiths and Charles Jim published a paper describing “a simple
`
`time-varying beamformer which can be used to combine the outputs of an array of
`
`sensors.” (Ex. 1005, 27.) The beamformer’s purpose was “to minimize the effects of
`
`noise and interference at the array output” while capturing the target signal. (Id.)
`
`Griffiths and Jim called their beamformer a “generalized sidelobe canceling”
`
`structure. (Id., 29.) Illustrated in Figure 4 of their paper, the signal processor had two
`
`main substructures: the top branch was a “conventional beamformer” designed to
`
`capture the target signal plus noise, and the bottom branch was the “sidelobe canceling
`
`path” that captures only noise so that the noise could be subtracted or canceled out:
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`3
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`
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`(Id. 29–30.1) In the top branch, the outputs of the array sensors were combined to
`
`form a conventional beamformer, which Petitioner calls the first virtual sensor. The
`
`sensor outputs were combined by multiplying the sensor output signals by factors
`
`called “weights” ((cid:1)(cid:2)1, … , (cid:1)(cid:2)M in the paper, and sometimes also called “gains”) and
`
`further filtering and summing the weighted sensor signals. (Id.; Ex. 1002 ¶35.) In the
`
`paper’s equations, the output of the first virtual sensor was denoted (cid:7)(cid:2) ′((cid:10)).(Ex. 1005,
`
`30.) This output contains the target signal plus noise. (Ex. 1002 ¶35.)
`
`“The lower path in Fig. 4 is the sidelobe canceling path” (Ex. 1005, 30), which
`
`Petitioner calls the second virtual sensor. Like the first virtual sensor, the second
`
`virtual sensor is formed from a combination of the outputs of the array sensors, but the
`
`combination differs from the combination used for the first virtual sensor. The lower
`
`
`1 Figures have been annotated with color throughout.
`4
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`path includes a blocking matrix designed to “block the desired signal ((cid:10))from the
`
`lower path.” (Id.) The array sensor outputs were combined by filtering and summing
`
`(including by blocking the desired signal), and the output of the second virtual sensor
`
`was denoted in the paper as ((cid:10)). (See id.) The second virtual sensor’s output “((cid:10)(cid:11)
`
`contains no desired signal terms” and instead “contains only noise and interference
`
`terms.” (Id.)
`
`The overall output of the GSC, ((cid:10)), was produced by subtracting the noise-only
`
`output of the second virtual sensor from the target-plus-noise output of the first virtual
`
`sensor:
`
`
`
`
`
`
`
`(Id.) The result was a cleaned-up signal that reduced noise without distorting the
`
`desired signal. (Ex. 1002 ¶40; Ex. 1005, 30 (output due to desired signal satisfies the
`
`constraint defined by paper’s equation 9, which defines a constraint for “zero
`
`distortion” (p. 28)).)
`
`B. Over the Next Two Decades, the GSC was
`Used in Microphone Arrays to Reduce Noise.
`
`In the 20 years following Griffiths and Jim’s article, the GSC was used in many
`
`signal-processing applications, including with microphone arrays to reduce noise in
`
`speech applications. For example, U.S. Patent No. 5,651,071 (“Lindemann”), filed
`
`in 1993, cites the article and explains that using a Griffiths-Jim beamformer “to
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`improve signal-to-noise ratio for hearing aids” was known. (Ex. 1007, 1:40-46,
`
`12:12–14.2) As another example, Griffiths-Jim is the first nonpatent reference cited in
`
`U.S. Patent No. 5,627,799 (“Hoshuyama”), filed in 1995, which relates to
`
`“interference cancelers, and more particularly to a generalized sidelobe canceler, or
`
`adaptive beamformer for an array of sensors such as microphones[.]” (Ex. 1008,
`
`1:8-11.) Describing what was prior art even then, Hoshuyama explains one way the
`
`GSC had been used with microphone arrays:
`
`According to a prior art microphone array, signals detected by an array of
`
`microphones are lowpass filtered and summed together to detect a target signal
`
`that arrives in a particular direction. The adaptive microphone array
`
`beamformer is one form of the generalized sidelobe canceler as described in
`
`an article “An alternative Approach to Linearly Constrained Adaptive
`
`Beamforming,” Lloyd J. Griffiths and Charles W. Jim, the IEEE Transactions
`
`on Antenna and Propagation, Vol. AP-30, No. 1, January 1982, pages 27-34.
`
`(Id., 1:17-26.)
`
`C. Published in 2001, Brandstein Illustrates How to
`Use a GSC with a Microphone Array to Reduce Noise.
`
`In 2001, MICROPHONE ARRAYS: SIGNAL PROCESSING TECHNIQUES
`
`AND APPLICATIONS published. (Ex. 1003 (“Brandstein”).) The editors’ goal was
`
`to provide “a single complete reference on microphone arrays.” (Id. Preface.) The
`
`book quickly became a standard reference for those in the field of audio-signal
`
`processing. (Ex.1002 ¶ 45.)
`
`
`2 Patent citations are in column:line format.
`6
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`IPR2023-01153
`U.S. Patent No. 11,122,357
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`
`At the outset of the chapter on robust adaptive beamforming, Brandstein
`
`explains that “[a]pplications of beamforming include microphone arrays for speech
`
`enhancement.” (Ex. 1003, 87 (original page numbering).) “The goal of speech
`
`enhancement is to remove undesirable signals such as noise and reverberation.” (Id.)
`
`Brandstein further explains that, among various known adaptive beamformers, “the
`
`Griffiths-Jim beamformer (GJBF), or the generalized sidelobe canceler, is most
`
`widely known.” (Id. 88 (internal citation omitted).) “Figure 5.1 depicts the structure of
`
`the GJBF.” (Id.)
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`(Id. 89, Fig. 5.1.) As shown, the signals of at least two physical microphones, (cid:12)0 ((cid:10))
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`and (cid:12)1((cid:10)), are combined in the top branch by filtering and summing the signals to form
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`a fixed beamformer—a first virtual microphone. (Ex. 1002 ¶48.) The first virtual
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`microphone captures the target speech signal plus noise. (Id.)
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`In the bottom branch, the signals of the two physical microphones are
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`combined by filtering and summing the signals in a different way to form a second
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`virtual microphone. (Id. ¶49.) The second virtual microphone includes a blocking
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`matrix (BM). (Id.) “[T]he BM forms a null in the look direction so that the target
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`signal is suppressed and all other signals are passed through.” (Ex. 1003, 88.) “The
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`BM was named after its function, which is to block the target signal.” (Id.) As a
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`result, the second virtual microphone captures noise only. (Ex. 1002 ¶49.)
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`The overall output is the target-plus-noise output of the first virtual
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`micro- phone minus the noise-only output of the second virtual microphone. (Id.
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`¶50.) The result is that, “in the subtracter output ((cid:10)), the target signal is enhanced
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`and undesirable signals such as ambient noise and interferences are suppressed.”
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`(Ex.1003, 88-89.)
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`The two virtual microphones have very different responses to the target speech
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`signal: the first virtual microphone is designed to capture the target signal, while the
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`second virtual microphone is designed to block it. (Ex. 1002 ¶51.) On the other hand,
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`they have similar responses to noise so that in the final subtraction output the noise is
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`removed. (Id.) This is illustrated in Figure 5.2, which shows the directivity pattern
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`for the final output of an example Griffiths-Jim beamformer:
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`(Ex. 1003, 89, Fig. 5.2.) The horizontal axis of the graph shows direction of arrival
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`measured in degrees relative to the microphone array: the target signal is shown at 0
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`degrees, while the noise signal is shown at approximately 45 degrees. (Ex. 1002
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`¶51.) The vertical axis of the graph shows gain in decibels: zero gain corresponds to
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`no change in sound pressure or signal power, a positive gain corresponds to an
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`increase in signal power, and a negative gain corresponds to a decrease in signal
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`power. (Id.)
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`As highlighted in green, the target signal is reproduced faithfully with
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`essentially zero gain, reflecting that subtracting the second virtual microphone’s
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`noise-only output from the first virtual microphone’s target-plus-noise output will
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`produce the target signal in the direction of the target. (Id. ¶52.) On the other hand, as
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`highlighted in red, Figure 5.2 shows a highly negative gain in the direction of the
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`interference signal, reflecting that subtracting the two virtual microphones’ outputs
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`cancels the noise. (Id. ¶53; see also Ex. 1003, 90 (“In the direction of the target signal,
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`almost constant gains close to 0 dB are obtained over a wide range of frequencies.
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`On the contrary, in the direction of the interference, a deep null is formed.”).)
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`D. Contemporaneously, Gannot Taught Adapting
`The GSC To Handle Arbitrary Transfer Functions.
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`In August 2001, IEEE’s Transactions on Signal Processing publication (vol. 49,
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`no. 8) included an article titled Signal Enhancement Using Beamforming and
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`Nonstationarity with Applications to Speech by Sharon Gannot, David Burshtein, and
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`Ehud Weinstein. (Ex. 1004 (“Gannot”).) As its title indicates, the article contemplates
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`speech enhancement through beamforming. (Id.) Specifically, the article considers a
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`sensor array “where arbitrary transfer functions (TFs) relate the source signal and the
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`sensors.” (Id. 1614 (Abstract).) As an audio signal travels from its source to a
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`microphone, the signal may change, such that the signal received at the microphone is
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`not exactly the same as the signal when it originated from the source. (Ex. 1002 ¶55.)
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`The acoustic path from the source to the microphone can be thought of as a system
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`that brings about this change, and the operation of the acoustic path on the signal can
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`be represented mathematically by a transfer function. (Id.)
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`Gannot notes that the generalized sidelobe canceler (GSC) works well when
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`the acoustic paths’ transfer functions satisfy certain criteria, such as when the signals
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`received at the sensors “are simple delayed versions of the source signal.” (Ex. 1004,
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`1614 (Abstract).) But the original Griffiths-Jim GSC may suppress interference
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`poorly “in complicated acoustic environments, where arbitrary TFs [transfer
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`functions] may be encountered.” (Id.) Gannot thus proposes a GSC solution adapted
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`to handle arbitrary transfer functions. (Id.)
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`Gannot’s Figure 3 shows the proposed GSC structure, and Figure 4 summarizes
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`the algorithm:
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`Ex. 1004, Fig. 3
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`Ex. 1004, Fig. 4
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`The blocking matrix ℋ† is used to create noise reference signals (cid:16)(cid:17) that apply the
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`linear transfer functions (cid:18)(cid:17) of the acoustical paths:
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`(Ex. 1004, 1618-20.) By incorporating these terms, Gannot’s more-general GSC
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`accounts for arbitrary transfer functions. In particular, by using the ratio of the transfer
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`function for microphone m to the transfer function for microphone 1, Gannot’s
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`algorithm applies a transfer function for an acoustical path between the two
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`microphones.3 (Ex. 1002 ¶61.)
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`E. Other Concepts in the ’357 Patent Were Well Known.
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`1.
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`Filtering And Summing In The
`Time Domain Were Well Known.
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`In the microphone-array context, the GSC involves filtering and summing
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`physical-microphone signals to create virtual microphones. It has been known since the
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`outset that the GSC can be implemented in the time domain, a term that refers to
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`analyzing signals as a function of time. (Ex. 1002 ¶35.) Both the original Griffiths-Jim
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`paper and Brandstein show the sensor signals as functions of time. (Id. ¶¶35, 48.)
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`Indeed, Lindemann discloses that using the GSC in a microphone array for hearing
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`aids was a “time domain approach.” (Ex. 1007, 1:51-52.)
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`3 The inventor named on the ’357 patent had another application publish as U.S.
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`2003/0128848 (“Burnett ’848”), which is prior art to the ’357 patent. (Ex. 1009.)
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`Burnett ’848 also discloses using a ratio of transfer functions representing the transfer
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`function of an acoustical path between microphones. (Ex. 1002 ¶¶71-75.) The ’357
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`patent’s discussion of transfer functions essentially repeats Burnett ’848’s disclosure,
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`which confirms that this feature was known in the art. (Id. ¶83.)
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`2.
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`Delaying Signals Based On Geometry To Adjust
`For Differences In Arrival Times Was Well Known.
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`Adaptive beamforming relies on the spatial geometry of the array and the
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`signal’s direction of arrival. (Ex. 1002 ¶62; Ex. 1003, 87.) When the source of the
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`target signal is close enough to the array, instead of treating the signal’s wavefront as
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`a plane, it may be useful to account for the spherical geometry of the wavefront—i.e.,
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`to use a near-field design. (See Ex. 1002 ¶¶63-64.) Near-field designs were well
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`known before the ’357 patent and use basic calculations to determine the delays
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`between signal arrival at the various microphones in the array. (Id.) Brandstein
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`discloses the standard near-field design, using c to denote the speed of sound:
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`(Ex. 1003, 25.) The time it takes for a signal to travel from a source to a microphone
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`is the distance traveled divided by the speed of sound. (Ex. 1002 ¶65.) The (cid:19)(cid:20) terms
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`above thus provide the difference in time it takes for