UNITED STATES PATENT AND TRADEMARK OFFICE
`____________________________________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________________________________________
`
`SPRINT SPECTRUM L.P., CELLCO PARTNERSHIP D/B/A VERIZON WIRELESS,
`AND AT&T MOBILITY LLC
`Petitioners
`
`v.
`
`ADAPTIX, INC.
`Patent Owner
`
`
`Case No. IPR2016-00823
`Patent 8,934,375
`
`
`PETITION FOR INTER PARTES REVIEW
`OF U.S. PATENT NO. 8,934,375
`Claims 1, 3, 9-10, 12, 15-17, 19, 25-26, 28, and 31-32
`
`
`
`
`
`

`
`
`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`
`TABLE OF CONTENTS
`
`Page
`
`I. INTRODUCTION .................................................................................................. 1
`
`II. GROUNDS FOR STANDING UNDER 37 C.F.R. § 42.104(A) ............................... 2
`
`III. IDENTIFICATION OF CHALLENGE AND RELIEF REQUESTED ............. 3
`
`IV. OVERVIEW of the ’375 Patent .............................................................................. 3
`A.
`The Alleged Invention of the ’375 Patent ............................................. 4
`B.
`Summary of the Prosecution History of the ’375 Patent ............................. 4
`C.
`Level of Ordinary Skill in the Art ......................................................... 5
`D.
`Claim Construction Under 37 C.F.R. § 42.104(b)(3) ........................... 5
`
`V. PRIOR ART .......................................................................................................... 7
`A.
`Summary of the Prior Art ...................................................................... 7
`B.
`Overview of Ritter ................................................................................... 7
`C.
`Overview of Gesbert ................................................................................ 9
`D.
`Overview of Thoumy ............................................................................ 10
`E.
`Overview of Gitlin ................................................................................. 10
`
`B.
`
`VI. SPECIFIC GROUNDS FOR PETITION .......................................................... 11
`A.
`Ground 1: Ritter in View of Gesbert and Thoumy Renders Claims 1,
`9, 12, 15-17, 25, 28, and 31-32 Obvious Under 35 U.S.C. § 103(a) .......... 11
`Ground 2: Ritter in View of Gesbert, Thoumy, and Gitlin Renders
`Claims 3, 10, 19, and 26 Obvious Under 35 U.S.C. § 103(a) ................... 37
`Ground 3: Thoumy in View of Gesbert Renders Claims 1, 9,
`15-17, 25, and 31-32 Obvious Under 35 U.S.C. § 103(a) .................. 41
`D. Ground 4: Thoumy in View of Gesbert and Gitlin Renders
`Claims 3, 10, 12, 19, 26, and 28 Obvious Under 35 U.S.C. §
`103(a) ................................................................................................... 54
`
`C.
`
`VII. MANDATORY NOTICES UNDER 37 C.F.R. § 42.8(A)(1) ............................... 56
`A.
`Real Party-In-Interest and Related Matters .............................................. 56
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`Lead and Back-Up Counsel ................................................................... 58
`
`CONCLUSION .................................................................................... 59
`
`
`
`B.
`
`VIII.
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`

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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`
`TABLE OF AUTHORITIES
`
` Page(s)
`
`
`
`Federal Cases
`
`DyStar Textilfarben GmbH & Co. Deutschland KG v. C.H. Patrick
`Co.,
`464 F.3d 1356 (Fed. Cir. 2006) .......................................................................... 21
`
`In re ICON Health & Fitness, Inc.,
`496 F.3d 1374 (Fed. Cir. 2007) ...................................................................... 6, 43
`
`KSR Int’l Co. v. Teleflex Inc.,
`550 U.S. 398 (2007) .....................................................................................passim
`
`Phillips v. AWH Corp.,
`415 F.3d 1303 (Fed. Cir. 2005) ............................................................................ 6
`
`In re Yamamoto,
`740 F.2d 1569 (Fed. Cir. 2004) ............................................................................ 5
`
`Federal Statutes
`
`35 U.S.C. § 102(b) ..................................................................................................... 7
`
`35 U.S.C. § 102(a) ................................................................................................... 10
`
`35 U.S.C. § 102(e) ............................................................................................... 9, 10
`
`35 U.S.C. § 103(a) ............................................................................................passim
`
`35 U.S.C. § 112 .......................................................................................................... 5
`
`35 U.S.C. §§ 311-319 ................................................................................................ 1
`
`35 U.S.C. § 315 .......................................................................................................... 7
`
`35 U.S.C. § 325 ........................................................................................................ 57
`
`Regulations
`
`37 C.F.R. § 42.8(A)(1) ............................................................................................. 56
`
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`37 C.F.R. § 42.8(b)(1) .............................................................................................. 56
`
`37 C.F.R. § 42.8(b)(2) .............................................................................................. 57
`
`37 C.F.R. § 42.8(b)(3)-(b)(4) ................................................................................... 58
`
`37 C.F.R. § 42.100 ..................................................................................................... 1
`
`37 C.F.R. § 42.100(b) ................................................................................................ 5
`
`37 C.F.R. § 42.104(A)................................................................................................ 2
`
`37 C.F.R. § 42.104(b)(3) ............................................................................................ 5
`
`37 C.F.R. 42.104(b)(4)-(5) ....................................................................................... 11
`
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`I.
`
`INTRODUCTION
`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`
`Pursuant to 35 U.S.C. §§ 311-319, and 37 C.F.R. § 42.100, Petitioners Sprint
`
`Spectrum L.P., Cellco Partnership d/b/a Verizon Wireless, and AT&T Mobility LLC
`
`(collectively “Petitioners”) request inter partes review (“IPR”) of claims 1, 3, 9-10, 12,
`
`15-17, 19, 25-26, 28, and 31-32 (the “Challenged Claims”) of U.S. Patent No. 8,934,375
`
`(the “’375 Patent,” attached as Ex. 1001), issued on January 13, 2015.1
`
`The ’375 Patent is currently being asserted against Petitioners in the United States
`
`District Court for the Eastern District of Texas. The ’375 Patent was applied for and
`
`issued in seven months during the course of other litigation against Petitioners involving
`
`related U.S. Patent Nos. 7,454,212 (the ‘212 Patent, Ex. 1018) and 6,947,748 (the ‘748
`
`Patent, Ex. 1017).2 The ’375 Patent relates to a well-known technique for adaptively
`
`allocating wireless frequency channels, called “subcarriers,” in an orthogonal frequency
`
`division multiple access (“OFDMA”) system. In particular, the ’375 Patent relates to a
`
`system and method for allocating subcarriers to remote devices, called “subscriber units,”
`
`and dynamically adjusting those allocations based on changing channel conditions.
`
`
`
`1 Petitioners are filing a second petition challenging other claims of the ’375 Patent.
`
`2 Final judgments have been entered in favor of Petitioners Verizon and AT&T in those
`
`other litigations.
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`Independent claims 1 and 17 recite three steps, each step performed twice. First,
`
`well-known pilot symbols are used by the subscriber unit to measure characteristics of
`
`the channel between the base station and the subscriber. Second, the subscriber unit sends
`
`feedback information to the base station. This feedback information includes (1) channel
`
`information for a plurality of feedback clusters (each feedback cluster being at least two
`
`subcarriers) and (2) an index corresponding to a desired modulation and coding rate for
`
`each feedback cluster. Third, the subscriber unit receives (1) an identification of the
`
`OFDMA subcarriers that have been allocated by the base station to the subscriber unit,
`
`and (2) an indication of the corresponding modulation and coding rate. The base station
`
`selects the subcarriers and the corresponding modulation and coding rate for use by the
`
`subscriber unit based on at least the feedback information provided by the subscriber unit.
`
`Finally, these three steps are performed a second time, and the second allocation of
`
`subcarriers is different from the first allocation of subcarriers.
`
`As set forth below, the subject matter of the ’375 Patent was well known, and the
`
`claimed inventions obvious, to those of skill in the art in 2000. Accordingly, Petitioners
`
`request inter partes review and subsequent cancellation of the challenged claims.
`
`II. GROUNDS FOR STANDING UNDER 37 C.F.R. § 42.104(A)
`Petitioners certify that the ’375 Patent is available for IPR and that Petitioners are
`
`not barred or estopped from requesting IPR of any claim of the ’375 Patent. Specifically,
`
`Petitioners state that: (1) no petitioning party owns the ’375 Patent; (2) no petitioning
`
`party has filed a civil action challenging the validity of any claim of the ’375 Patent; and
`
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`

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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`(3) this Petition was filed less than one year after each petitioning party was served with a
`
`complaint alleging infringement of the ’375 Patent.
`
`III.
`
`IDENTIFICATION OF CHALLENGE AND RELIEF REQUESTED
`
`Petitioners challenge claims 1, 3, 9-10, 12, 15-17, 19, 25-26, 28, and 31-32 of
`
`the ’375 Patent on the following grounds:
`
`Challenged Claims
`1, 9, 12, 15-17, 25, 28, 31-32
`3, 10, 19, 26
`1, 9, 15-17, 25, 31, 32
`3, 10, 12, 19, 26, 28
`
`References
`Basis
`§ 103(a) Ritter, Gesbert, & Thoumy
`§ 103(a) Ritter, Gesbert, Thoumy, & Gitlin
`§ 103(a) Thoumy & Gesbert
`§ 103(a) Thoumy, Gesbert, & Gitlin
`
`
`Section IV.D identifies how the Challenged Claims are to be construed. Section VI
`
`identifies (1) the statutory grounds on which the challenge to each claim is based, (2) an
`
`explanation as to how each Challenged Claim is unpatentable for each ground, and (3)
`
`the exhibit numbers and relevance of the supporting evidence (attached as Exs. 1001–
`
`1020). The expert declaration of Richard Gitlin, Sc.D. (attached as Ex. 1002) is provided
`
`in further support of this Petition. Taken together, this evidence establishes a reasonable
`
`likelihood that Petitioners will prevail as to the Challenged Claims.
`
`IV. OVERVIEW OF THE ’375 PATENT
`
`The ’375 Patent issued on January 13, 2015, from Application No. 14/294,106,
`
`which was filed seven months earlier on June 2, 2014 with a Track 1 Request. The ’375
`
`Patent claims priority to, among other applications, (1) Application No. 09/738,086, filed
`
`on December 15, 2000, and issued as the ’748 Patent and (2) Application No.
`
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`11/199,586, filed on August 8, 2005, and issued as the ’212 Patent. All three patents
`
`share a common specification. According to Patent Office records, the ’375 Patent is
`
`currently assigned to Adaptix, Inc. (“Adaptix” or “Patent Owner”). Ex. 1002, Gitlin
`
`Decl. at ¶¶ 42-44.
`
`The Alleged Invention of the ’375 Patent
`
`A.
`The claims of the ’375 Patent recite a method and apparatus for adaptively
`
`allocating subcarriers in an orthogonal frequency division multiple access (“OFDMA”)
`
`system. Generally speaking, the claimed invention requires a subscriber unit to (1)
`
`measure channel information for subcarriers based on pilot symbols received from a base
`
`station; (2) provide feedback information to the base station, including a modulation and
`
`coding rate, for clusters of subcarriers based on the measurements; (3) receive an
`
`allocation of OFDMA subcarriers from the base station, including a modulation and
`
`coding rate, selected by the base station for use by the subscriber unit; and (4) repeat
`
`these steps at a second time to receive a second allocation of OFDMA subcarriers that is
`
`different from the first allocation. See, e.g., Claim 1; Ex. 1002, Gitlin Decl. at ¶ 43.
`
`Summary of the Prosecution History of the ’375 Patent
`
`B.
`During prosecution, the Patent Owner submitted five Information Disclosure
`
`Statements (including a 48 page Form PTO-1449 upon initial filing), citing over 1,400
`
`references, including hundreds of documents from pending litigation involving the ’748
`
`Patent (Ex. 1017) and the ’212 Patent (Ex. 1018). The Examiner noted that “the number
`
`of references submitted is unreasonably large in quantity and without any indication of
`
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`relevancy. Examiner made only a best effort in considering all of them. Any reference
`
`that may have escaped the Examiner’s attention thus is because of this large number of
`
`reference[s] and application shares the burden for both, submitting a large quantity of
`
`references and failing to indicate the relevant ones.” Ex. 1013, File History of
`
`14/294,106, June 27, 2014 Non-Final Rejection at page 2. After multiple clarifying
`
`amendments to address rejections under 35 U.S.C. § 112, the Examiner issued a final
`
`notice of allowance. Id. at December 2, 2014, Notice of Allowance. Ex. 1002, Gitlin
`
`Decl. at ¶ 45.
`
`Level of Ordinary Skill in the Art
`
`C.
`A person having ordinary skill in the art in 2000 (when the first application leading to the
`
`’375 Patent was filed) would have had either a Bachelor’s degree in electrical
`
`engineering or a similar degree, with at least three to four years of experience in wireless
`
`communication technology or other communication-related technology, or a Master’s
`
`degree in electrical engineering or a similar degree, with at least two years of experience
`
`in wireless communication technology or other communication-related technology. Ex.
`
`1002, Gitlin Decl. at ¶¶ 25-29.
`
`D. Claim Construction Under 37 C.F.R. § 42.104(b)(3)
`A claim in inter partes review is given the “broadest reasonable construction in
`
`light of the specification in which it appears.” 37 C.F.R. § 42.100(b). The broadest
`
`reasonable construction is the broadest reasonable interpretation of the claim language.
`
`See In re Yamamoto, 740 F.2d 1569, 1572 (Fed. Cir. 2004). Any claim term that lacks a
`
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`definition in the specification is therefore also given a broad interpretation. In re ICON
`
`Health & Fitness, Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). Further, applying the claim
`
`construction standard of Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) would
`
`not change the analysis or conclusions covered in this petition. The prior art teaches each
`
`claim limitation under any reasonable interpretation of the claim terms, and the analysis is
`
`not dependent on application of the "broadest reasonable interpretation" standard. Ex.
`
`1002, Gitlin Decl. at ¶ 31.
`
`“pilot symbols”
`
`1.
`In other litigation and a PTAB proceeding involving the ’748 Patent, the term
`
`“pilot symbols” was construed to mean “symbols, sequences, or signals known to
`
`both the base station and subscriber.” Ex. 1012, Claim Construction Order, 6:13-cv-
`
`438, Dkt. 901 (E.D. Tex., Sept. 19, 2-14) at 17; Ex. 1011, IPR2015-00319 Institution
`
`Decision, Paper 10. Further, the specification of the ’375 Patent discloses that
`
`“pilot symbols, often referred to as a sounding sequence or signal, are known to
`
`both the base station and the subscribers.” Ex. 1001, ’375 Patent at 5:38-40.
`
`Accordingly, the broadest reasonable construction of “pilot symbols” is “symbols,
`
`sequences, or signals known to both the base station and subscriber.” Ex. 1002,
`
`Gitlin Decl. at ¶ 32.
`
`“cluster”
`
`2.
`The specification of the ’375 Patent defines a “cluster” as “a logical unit that
`
`contains at least one physical subcarrier.” Ex. 1001, ’375 Patent at 5:20-21.
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`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`Accordingly, the broadest reasonable construction of “cluster” is “a logical unit
`
`that contains at least one physical subcarrier.” Ex. 1002, Gitlin Decl. at ¶ 33.
`
`V.
`
`PRIOR ART
`A.
`The subject matter claimed in the ’375 Patent – adaptive allocation of subcarriers in an
`
`Summary of the Prior Art
`
`OFDMA system based on channel quality measurements – was well known and obvious
`
`as of December 15, 2000, the filing date of the ’375 Patent’s priority application. Each of
`
`the prior art references relied upon in this petition has an effective filing date earlier than
`
`December 15, 2000. Ex. 1002, Gitlin Decl. at ¶ 27.
`
`B. Overview of Ritter
`German Patent DE 19800953 C1 to Ritter (Ex. 1003) is entitled “Procedure and Radio
`
`Communication System to Allocate the Radio Resources of a Radio Interface” (“Ritter”).
`
`Ritter was published on July 29, 1999, and is prior art to the ’375 Patent under 35 U.S.C.
`
`§ 102(b). Ex. 1004, Ritter at 1. Ritter was cited on the face of the ’375 Patent, but was not
`
`substantively discussed during prosecution of the application that issued as the ’375
`
`Patent. The English translation of Ritter (Ex. 1004) was substantively considered during
`
`prosecution of the ’212 Patent. See, e.g., Ex. 1008, ’212 Pros. Hist. Ritter was also
`
`substantively considered by the Board in multiple IPR petitions challenging claims of the
`
`related ’748 and ’212 Patents. Notably, the Board has previously found a reasonable
`
`likelihood that Ritter in combination with one or more secondary references rendered
`
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`invalid similar claims in the related ’748 and ’212 Patents.3 Ex. 1009, IPR2014-01525,
`
`Institution Decision, Paper No. 15; Ex. 1010, IPR2014-01524, Institution Decision, Paper
`
`No. 16; Ex. 1011, IPR2015-00319, Institution Decision, Paper No. 10. Ex. 1002, Gitlin
`
`Decl. at ¶ 47.
`
`Ritter teaches an OFDMA wireless communication system in which sets of OFDMA
`
`subcarriers, referred to as “segments” are allocated between a base station and multiple
`
`mobile stations. Ex. 1004, Ritter at 2-3. Each mobile station uses a training sequence to
`
`measure the channel quality of segments of the frequency spectrum and transmits
`
`feedback information to the base station identifying suitable segments. Using this
`
`feedback information, the base station allocates a segment to each mobile station for data
`
`transmission. Id. at 4-5. A “segment” in Ritter, like a “cluster in the ’375 Patent, may
`
`comprise a plurality of subcarriers. Id. at 12-13 (disclosing, as an example, segment Sx
`
`comprising subcarriers oc00 – oc40); see also Ex. 1002, Gitlin Decl. at ¶ 48.
`
`
`
`3 While the IPR proceeding for the ’212 Patent was terminated prior to the hearing due to
`
`settlement of the underlying dispute, the Board entered an adverse judgment against
`
`Adaptix (at Adaptix’s request) in both IPR proceedings related to the ’748 Patent
`
`(IPR2014-01524 and IPR2015-00319), cancelling all claims subject to the IPR. Ex. 1014,
`
`IPR2014-01525, Termination-Settlement, Paper No. 43; Ex. 1015, IPR2014-01524,
`
`Judgment-Termination of Proceeding, Paper No. 30; Ex. 1016, IPR2015-00319,
`
`Judgment, Paper No. 15.
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
`C. Overview of Gesbert
`U.S. Patent No. 6,760,882 to Gesbert (“Gesbert”) was filed on September 19,
`
`2000, and issued on July 6, 2004. Gesbert is prior art to the ’375 Patent under 35 U.S.C. §
`
`102(e). Ex. 1005. Gesbert was cited on the face of the ’375 Patent, but was not
`
`substantively discussed during prosecution. Gesbert generally teaches a wireless
`
`communication system in which modulation and coding rates are dynamically
`
`selected based on measured channel quality between a base station and subscriber
`
`units. Ex. 1005, Gesbert at 3:60-4:6, Fig. 1; Ex. 1002, Gitlin Decl. at ¶ 49.
`
`Gesbert expressly teaches that its concepts can be used in an OFDMA wireless
`
`system. Ex. 1005, Gesbert at 3:57-59. To assess channel quality, Gesbert teaches that
`
`“training tones” are transmitted on each subcarrier by the base station. Id. at 8:14-19.
`
`These training tones are then used by the subscriber units to measure the quality of
`
`each channel. Id. at 5:24-54 (describing measurements on channels between BTS base
`
`station and subscriber units), 7:7-62 (same), 8:13-34 (describing a matrix that maps
`
`channel quality for each training phase), Fig. 5 (illustrating multiple sequences of
`
`training tones transmitted on each subcarrier). Based on these measurements,
`
`feedback information is transmitted from each subscriber unit to the base station. Id. at
`
`9:52-10:8. Within this feedback information, the subscriber unit includes a “mode”
`
`that
`
`indicates a modulation and coding rate
`
`to be used for subsequent
`
`communications. Id. at 4:30-32 (“The system also has a feedback mechanism for
`
`communicating the subsequent mode from the receive unit to the transmit unit.”),
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`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`6:35-39 (explaining that modes “identify the modulation and coding rates which are to
`
`be applied to data”), Table 1; see also Ex. 1002, Gitlin Decl. at ¶ 50.4
`
`D. Overview of Thoumy
`U.S. Patent No. 7,039,120 to Thoumy (“Thoumy”) was filed on November 30,
`
`1999, and issued on May 2, 2006. Ex. 1007. Thoumy is prior art to the ’375 Patent
`
`under 35 U.S.C. § 102(e) and was not cited on the face of the ’375 Patent. Thoumy
`
`discloses a system for dynamic allocation of carrier frequencies in an OFDMA
`
`system. Ex. 1007, Thoumy at 13:10-19. Thoumy discloses a network with multiple
`
`peripheral stations (id. at 15:17-19 (“FIG. 14 is a general view of a network according
`
`to the invention including a base station SIB [sic] and several peripheral stations SPi”)
`
`& Fig. 14), implementing OFDM (id. at 1:28-41 (“one particular case is Orthogonal
`
`Frequency Division Multiplex, or OFDM”)). Thoumy discloses continuously
`
`monitoring the actual conditions of the channel for transmission, providing feedback
`
`to the base station, and adapting the number of carriers and modulation based on those
`
`measurements. Id. at 13:20-23; see also Ex. 1002, Gitlin Decl. at ¶¶ 51-52.
`
`E. Overview of Gitlin
`U.S. Patent No. 6,018,528 to Gitlin (“Gitlin”) was filed on April 28, 1994, and
`
`issued on January 25, 2000. Ex. 1006. Gitlin is prior art to the ’375 Patent under at
`
`least 35 U.S.C. § 102(a). Gitlin was cited on the face of the ’375 Patent, but was not
`
`substantively discussed during prosecution. Gitlin discloses a system and method for
`
`
`
`4 Unless otherwise indicated, all emphasis is added.
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`optimizing frequency allocation to multiple subscribers by using contiguous and non-
`
`contiguous frequency assignments for multi-tone, i.e., OFDMA, systems. Ex. 1006,
`
`Gitlin at 3:1-12, 5:32-6:18, Fig. 6; see also Ex. 1002, Gitlin Decl. at ¶ 53.
`
`VI. SPECIFIC GROUNDS FOR PETITION
`Pursuant to Rule 42.104(b)(4)-(5), the below sections, as confirmed by Dr.
`
`Richard Gitlin (Ex. 1002), demonstrate how the prior art discloses each and every
`
`limitation of the challenged claims of the ’375 Patent, and how those claims are
`
`rendered obvious by the prior art.
`
`A. Ground 1: Ritter in View of Gesbert and Thoumy Renders Claims 1,
`9, 12, 15-17, 25, 28, and 31-32 Obvious Under 35 U.S.C. § 103(a)
`1.
`One of ordinary skill in the art in 2000 would understand that Ritter
`
`Independent claims 1 and 17
`
`combined with Gesbert and Thoumy renders obvious claims 1 and 17 under 35
`
`U.S.C. § 103(a). Claim 1, a method claim, and claim 17, an apparatus claim,
`
`contain nearly identical limitations. Accordingly, Petitioners address these
`
`common limitations of claims 1 and 17 together, with reference to claim 1, in the
`
`ground below. Claim 17 additionally requires a processor in the subscriber unit to
`
`perform the recited steps. Ritter discloses a control means in the mobile station for
`
`measuring channel quality, selecting carriers, and transmitting and receiving
`
`information from the base station. Ex. 1004, Ritter at 5 (“Control means in each
`
`mobile station to measure the quality of various segments … [and] transmit
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`

`
`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`appropriate information to the base station”). Ritter therefore teaches this
`
`limitation. Ex. 1002, Gitlin Decl. at ¶ 54.
`
`(a)
`
`[Claim 1] The preamble: A method for a wireless system
`employing orthogonal frequency division multiple access
`(OFDMA):
`
`Ritter discloses “a wireless system employing orthogonal frequency division
`
`multiple access (OFDMA).” Specifically, Ritter discloses that “[t]he procedure of
`
`the invention begins with the OFDMA multi-carrier procedure and the use of a
`
`number of subcarriers which are assigned for the communication link between the
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`base station and the mobile stations.” Ex. 1004, Ritter at 4; see also id. at 4-5
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`(describing a wireless OFDMA system for allocating sets of subcarriers to multiple
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`users); Ex. 1002, Gitlin Decl. at ¶ 56.
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`(b)
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`[Claim 1] Limitation (a): measuring, at a first time by a
`subscriber unit, a first channel information for a plurality
`of subcarriers based on a first plurality of pilot symbols
`received from a base station
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`Ritter teaches that each subscriber unit measures channel quality information for
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`subcarriers between it and a base station. For example, Ritter discloses that:
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`“[a]nother advantageous model of the invention to measure the quality of
`segments of the frequency spectrum envisions, that the mobile station
`receives all subcarriers in the time slot allocated to it, checks for each
`subcarrier, whether an amplitude modulation of the data symbols
`transmitted in the time slot is present, and forms an average value from the
`results of the test for all subcarriers belonging to the respective segment.
`The advantage lies in the two-step procedure in which initially the quality
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`is determined for the individual subcarriers and then the quality of the
`subcarriers can be ascertained to determine the quality of the segment
`that was examined in particular.”
`Ex. 1004, Ritter at 8-9; see also id. at 12; Ex. 1002, Gitlin Decl. at 57.
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`To the extent the Patent Owner argues that Ritter does not explicitly disclose
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`“measuring . . . based on a first plurality of pilot symbols,” it would have nevertheless
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`been obvious to measure channel quality using pilot symbols in view of Gesbert. In
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`particular, Gesbert teaches an OFDMA system that performs subcarrier quality
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`measurements based on training tones (known to both the subscriber and base station)
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`received from the base station. See, e.g., Ex. 1005, Gesbert at 8:13-34. Gesbert explains
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`that “FIG. 5 indicates that training is performed on all tones during an OFDM training
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`symbol, it will be clear to a person skilled in the art that a subset of these tones could be
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`used for training and the corresponding frequency response could be computed at the
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`receiver by interpolating.” Id. at 7:16-20. Gesbert uses these training tones to measure
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`channel quality:
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`“SINR is sampled during training tones T occurring during sampling
`window τ1. The present embodiment uses multiple carrier frequencies fc
`and thus the SINR is sampled and computed by block 102 for data 52
`transmitted at each of the n carrier frequencies fc. By buffering the SINR
`values for all the training tones T during time window τ1 statistics
`computation block 102 constructs the following matrix:
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`
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`where SINRi,j is the SINR at the i-th carrier frequency fci during training
`phase j. There are thus 1 to n carrier frequencies fc and 1 to w training
`phases.”
`Id. at 8:13-34; see also id. at 7:57-59 (“quality parameters include signal-to-interference
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`and noise ratio (SINR)”). One of ordinary skill in the art in 2000 would understand these
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`training tones of Gesbert to be the claimed “pilot symbols” according to the construction
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`proffered above at least because the training tones are necessarily known to both the base
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`station and subscriber. See supra IV.D.1. Indeed, the use of training tones was well
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`known by those of ordinary skill in the art in 2000.5 Ex. 1002, Gitlin Decl. at ¶¶ 58-60.
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`Like Ritter and the ’375 Patent, Gesbert teaches an OFDMA system in which
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`subscriber units (e.g., handsets) measure the quality of a wireless channel and provide
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`feedback to the base station based on those measurements. Compare Ex. 1005, Gesbert at
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`2:61-65 (“One or more quality parameters are sampled in the data received by the
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`receive unit. Then, a first-order statistical parameter and a second-order statistical
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`parameter of the quality parameter are computed and used for selecting a subsequent
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`
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`5 See, e.g., Bahai and Saltzberg, “Multi-Carrier Digital Communications Theory and
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`Applications of OFDM,” (Kluwer Academic Publishers 1999), Ex. 1020, at 29
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`(“Usually, OFDM systems provide pilot signals for channel estimation.”).
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`mode for encoding the data.”), 4:30-32 (“The system also has a feedback mechanism
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`for communicating the subsequent mode from the receive unit to the transmit unit.”),
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`with Ex. 1004, Ritter at 12-13 (“According to the device of the invention every mobile
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`station, MS, measures the quality of various segments of the frequency spectrum,
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`whereby it receives all subcarriers in the time slot assigned to it, checks the quality of
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`each individual subcarrier and then determines the quality of the subcarriers. Then
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`each mobile station determines at least a suitable segment preferred for its own
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`communication link and transmits appropriate information to the base station, BS.”);
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`see also Ex. 1002, Gitlin Decl. at ¶ 61.
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`It would have been obvious to use pilot symbols to measure channel quality
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`in the system of Ritter as taught by Gesbert for at least the following reasons. One
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`rationale to combine is: “application of a known technique to a piece of prior art ready for
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`the improvement” to “yield predictable results.” KSR Int'l Co. v. Teleflex Inc., 550 U.S.
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`398, 401 (2007). Base system: Ritter discloses an OFDMA system that dynamically
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`allocates subcarrier segments (i.e., subcarriers) to a mobile station (i.e., subscriber unit)
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`based on the quality of the segments. Ex. 1004, Ritter at 8-9, 14. Ritter discloses using
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`pilot symbols. Id. at 16 (disclosing “training sequences” within data transmission
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`between base station and subscriber units). Known technique: As shown by Gesbert,
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`using pilot symbols within an OFDMA wireless communication system to measure
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`channel quality was well known in the art at the time of the alleged invention, and was a
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`simple design choice from among many possible alternatives. Ex. 1005, Gesbert at 8:13-
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`Petition for Inter Partes Review of
`U.S. Patent No. 8,934,375
`34. Even the ’375 Patent acknowledges that measuring channel quality based on pilot
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`symbols was a well-known technique. Ex. 1001, ’375 Patent at 9:14-17 (“The
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`channel/interference estimation by processing block 301 is well-known in the art by
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`monitoring the interference that is generated due to full-bandwidth pilot symbols being
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`simultaneously broadcast in multiple cells.”). Predictable results and improved
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`system: One of ordinary skill in the art would have been motivated to modify Ritter to
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`measure channel quality using pilot symbols, as taught by Gesbert, to obtain the
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`predictable results of an improved channel allocation process. As such, channel quality
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`measurements base