Trials@uspto.gov
`571-272-7822
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` Paper 35
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` Entered: January 21, 2016
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`
`
`ERICSSON INC. AND TELEFONAKTIEBOLAGET
`LM ERICSSON,
`Petitioner,
`
`
`v.
`
`
`
`INTELLECTUAL VENTURES II LLC,
`Patent Owner.
`____________
`
`
`
`Case IPR2014-01185
`Patent 7,269,127 B2
`____________
`
`
`
`
`
`Before JUSTIN BUSCH, PETER P. CHEN, and J. JOHN LEE,
`Administrative Patent Judges.
`
`CHEN, Administrative Patent Judge.
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
`
`
`571-272-7822
`
`
`
`
`
`
`
`
`
`
`
` Paper 35
`
` Entered: January 21, 2016
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`
`
`ERICSSON INC. AND TELEFONAKTIEBOLAGET
`LM ERICSSON,
`Petitioner,
`
`
`v.
`
`
`
`INTELLECTUAL VENTURES II LLC,
`Patent Owner.
`____________
`
`
`
`Case IPR2014-01185
`Patent 7,269,127 B2
`____________
`
`
`
`
`
`Before JUSTIN BUSCH, PETER P. CHEN, and J. JOHN LEE,
`Administrative Patent Judges.
`
`CHEN, Administrative Patent Judge.
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
`
`
`
`IPR2014-01185
`Patent 7,269,127 B2
`
`
`I. INTRODUCTION
`
`Ericsson Inc. and Telefonaktiebolaget LM Ericsson (“Petitioner”)
`
`filed a Petition requesting an inter partes review of claims 1–10, 17, 20, 21,
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`23, and 24 of U.S. Patent No. 7,269,127 (Ex. 1001, “the ’127 patent”).
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`Paper 2 (“Pet.”). Intellectual Ventures II LLC (“Patent Owner”) filed a
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`Preliminary Response. Paper 10 (“Prelim. Resp.”). On January 28, 2015,
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`we instituted an inter partes review of claims 1–10 and 17, but we did not
`
`institute an inter partes review of claims 20, 21, 23, and 24. Paper 11 (“Dec.
`
`to Inst.”).
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`After institution of trial, Patent Owner filed a Patent Owner Response
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`(Paper 19, “PO Resp.”), to which Petitioner filed a Reply (Paper 22, “Pet.
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`Reply”). Patent Owner filed a Motion for Observations on the Cross-
`
`Examination of Zygmunt Haas, Ph.D. (Paper 27), to which Petitioner
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`responded (Paper 31). An oral hearing was held on October 21, 2015. The
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`transcript of the consolidated hearing has been entered into the record.
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`Paper 34 (“Tr.”).
`
`The Board has statutory authority under 35 U.S.C. § 6(c). In this
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`Final Written Decision, issued pursuant to 35 U.S.C. § 318(a) and 37 C.F.R.
`
`§ 42.73, we determine Petitioner has shown by a preponderance of the
`
`evidence that claims 1–10 and 17 of the ʼ127 patent are unpatentable.
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`A. Related Proceedings
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`According to Petitioner, the ’127 patent is involved in the following
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`district court cases: Intellectual Ventures I LLC, et al. v. AT&T Mobility
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`2
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`IPR2014-01185
`Patent 7,269,127 B2
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`LLC et al., 1-13-cv-01668 (D. Del.); Intellectual Ventures I LLC, et al. v.
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`Leap Wireless Int’l et al., 1-13-cv-01669 (D. Del.); Intellectual Ventures I
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`LLC, et al. v. Nextel Operations et al., 1-13-cv-01670 (D. Del.); Intellectual
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`Ventures I LLC, et al. v. T-Mobile USA Inc. et al., 1-13-cv-01671 (D. Del.);
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`and Intellectual Ventures I LLC, et al. v. U.S. Cellular Corp., 1-13-cv-01672
`
`(D. Del.).
`
`B. The ’127 Patent
`
`The ’127 patent is titled, “Preamble Structures for Single-Input,
`
`Single-Output (SISO) and Multi-Input, Multi-Output (MIMO)
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`Communication Systems.” The subject matter of the challenged claims of
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`the ’127 patent relates generally to increased operating efficiency in wireless
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`communication systems, and, in particular, to preamble structures in multi-
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`input, multi-output (MIMO) wireless communication systems with two or
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`more transmit and receive antennas, and single-input, single-output (SISO)
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`wireless systems with one transmit and one receive antenna. Ex. 1001,
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`1:29–40, 3:21–24. In MIMO wireless communications systems, signals are
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`pre-processed to avoid interference from other signals in common
`
`communications channels or paths. Id. at 1:54–57. Pre-processing
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`techniques can include using frame structures, which are comprised of
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`preamble structures and data structures. Id. at 1:58–63. An efficient
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`preamble structure for use in wireless communications systems should
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`provide for both synchronization of data symbols and estimation of
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`parameters such as noise variance and other parameters. Id. at 2:56–62.
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`3
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`IPR2014-01185
`Patent 7,269,127 B2
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`Figure 1 of the ’127 patent is reproduced below.
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`
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`Figure 1 is a block diagram of exemplary MIMO communication system 10.
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`Id. at 4:3–4, 39–40. MIMO system 10 may be implemented as a wireless
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`system for transmission from transmitter 14 across wireless channel 12 to
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`receiver 16. Id. at 4:43–46, 5:8–10. Transmitter 14 includes encoder 18,
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`which typically encodes data and/or other types of signals received, for
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`example, from data source 20. Id. at 5:13–15.
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`A MIMO communication system may employ various signal
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`modulation and demodulation techniques, including orthogonal frequency
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`division multiplexing (OFDM). Id. at 4:58–62. Modulators 24-1 to 24-Q
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`modulate signals for transmission using, for example, OFDM techniques.
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`Id. at 5:31–35. In particular, modulators 24 include an inverse discrete
`
`4
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`IPR2014-01185
`Patent 7,269,127 B2
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`Fourier transform (IDFT) stage that receives a parallel format of training
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`blocks and data blocks and converts them from the frequency domain to the
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`time domain. Id. at 8:1-5. Within the modulator, the converted signals are
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`input to an amplifier and then to transmit antennas 26-1 to 26-Q, which
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`transmit the signals across channel 12. Id. at 8:31–34.
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`Data or information (e.g., voice, video, audio, text) can be transmitted
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`as data symbols organized into data structures. Id. at 1:64–2:1. Training
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`symbols are typically added as prefixes to data structures, to enable
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`synchronization between transmitters and receivers of a communications
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`system. Id. at 2:10–14. These training symbols can be referred to as
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`preambles and are part of the preamble structures. Id. at 2:14–15. The
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`preamble structure can contain an enhanced training symbol, which is
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`divided into sections to perform synchronization and channel parameter
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`estimation functions. Id. at 11:2–8.
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`Pilot symbols “have the same structure as preambles. However,
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`instead of being placed as a prefix to the data structure, the pilot structures
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`are periodically arranged within groups of data symbols.” Id. at 2:17–22.
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`Figure 2 of the ’127 patent is reproduced below.
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`5
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`IPR2014-01185
`Patent 7,269,127 B2
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`Figure 2 is a block diagram of encoder 18. Id. at 4:5–6. Encoder 18
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`includes pilot training symbol inserter 46, which “provides pilot blocks and
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`training blocks that are inserted into (or combined with) the data blocks” by
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`adders 44-1 to 44-Q. Id. at 7:14–25. The pilot blocks, or pilot symbols, are
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`“transmitted with data blocks to calibrate (i.e., synchronize) the receiver 16
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`to the transmitter 14 on a small scale.” Id. at 7:40–42. The specification
`
`explains that:
`
`The term pilot blocks, as used in this description, refers to
`symbols provided by the pilot/training symbol inserter 46, which
`are inserted periodically into the data blocks. Typically, pilot
`symbols may be inserted at any point in the data blocks. The term
`training blocks refers to one or more continuous sections of
`symbols provided by the pilot/training symbol inserter 46.
`
`
`Id. at 7:26–30. Figure 6 of the ’127 patent is reproduced below.
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`6
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`IPR2014-01185
`Patent 7,269,127 B2
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`Figure 6 is a diagram of frame structures 68 in signal structure 66. Ex. 1001,
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`10:50–55. Each of frame structures 68 includes preamble structure 70 and
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`data structure 72. Id. at 10:57–59. Preamble structure 70 includes training
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`symbol 74, and enhanced training symbol 79 located at the beginning of
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`preamble structure 70. Id. at 10:62–11:5. Training block 78 of enhanced
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`training symbol 79 is divided into several sections, for synchronization and
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`for channel parameter estimation. Id. at 11:5–8. Data structure 72 includes
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`one or more data symbols 80, which in turn include cyclic prefix 76 and data
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`block 82. Id. at 11:27–30. The specification states:
`
`Although omitted from FIG. 6 for simplicity, pilot symbols may
`also be intermittently inserted into the data symbols 80 by the
`pilot/training symbol inserter 46, as discussed above.
`
`
`Id. at 11:44–47.
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`7
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`IPR2014-01185
`Patent 7,269,127 B2
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`
`Illustrative Claim
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`Claims 1–10 and 17 are the subject of the trial. Claim 1 is
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`independent and is reproduced as follows.
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`1. A transmitter of a communication system, the transmitter
`comprising:
`
`an encoder having a pilot/training symbol inserter, the
`pilot/training symbol inserter configured to insert pilot
`symbols into data blocks and to combine training
`symbols with the data blocks;
`
`at least one modulator, each modulator having an inverse
`discrete Fourier transform (TDFT) [sic] stage and a cyclic
`prefix inserter, each modulator outputting a frame
`structure comprising a preamble structure and a data
`structure, the preamble structure comprising at least
`one training symbol and an enhanced training symbol; and
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`at least one transmit antenna, each transmit antenna
`corresponding to a respective one or the at least one
`modulator, each transmit antenna transmitting the frame structure
`output from the corresponding modulator, wherein the enhanced
`training symbol is a single symbol.
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`Id. at 16:52–17:3.
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`
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`8
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`IPR2014-01185
`Patent 7,269,127 B2
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`C. Prior Art Supporting the Instituted Challenges
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`The following four prior art references were asserted in the instituted
`
`grounds.
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`Reference
`
`Title
`
`Date
`
`Schmidl
`
`US 5,732,113
`
`Arslan
`
`US 6,411,649
`
`Kim
`
`US 7,012,881
`
`Heiskala
`
`US 6,298,035
`
`Mar. 24, 1998 (filed
`June 20, 1996)
`
`June 25, 2002 (filed
`Oct. 20, 1998)
`
`Mar. 14, 2006 (filed
`Dec. 29, 2000)
`
`Oct. 2, 2001 (filed
`Dec. 21, 1999)
`
`Ex. No.
`
`Ex. 1002
`
`Ex. 1003
`
`Ex. 1004
`
`Ex. 1006
`
`D. The Instituted Challenges of Unpatentability
`
`The following table summarizes the challenges to patentability on which
`
`we instituted inter partes review.
`
`References
`
`Basis
`
`Claim(s) Challenged
`
`Schmidl and Arslan
`
`§ 103(a) 1–3, 5
`
`Schmidl, Arslan, and Kim
`
`§ 103(a) 4, 6–10
`
`Schmidl, Arslan, Kim, and
`Heiskala
`
`§ 103(a) 17
`
`9
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`IPR2014-01185
`Patent 7,269,127 B2
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`
`II. ANALYSIS
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`A. Claim Construction
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`In an inter partes review, claim terms in an unexpired patent are
`
`interpreted according to their broadest reasonable construction in light of the
`
`specification of the patent in which they appear. See 37 C.F.R. § 42.100(b);
`
`In re Cuozzo Speed Techs., LLC, 793 F.3d 1268, 1275–79 (Fed. Cir. 2015).
`
`The claim language should be read in light of the specification as it would be
`
`interpreted by one of ordinary skill in the art. In re Am. Acad. of Sci. Tech.
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`Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004). Claim terms generally are given
`
`their ordinary and customary meaning, as would be understood by one of
`
`ordinary skill in the art in the context of the entire disclosure. See In re
`
`Translogic Tech., Inc., 504 F.3d 1249, 1257 (Fed. Cir. 2007). Only those
`
`terms in controversy need to be construed, and only to the extent necessary
`
`to resolve the controversy. Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200
`
`F.3d 795, 803 (Fed. Cir. 1999).
`
`In the Decision to Institute, we construed an “enhanced training
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`symbol” as “a training symbol, comprising a plurality of sections including
`
`repeated sequences, and providing at least a synchronization function.”
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`Paper 11, 8–9. Neither party contests that construction in their post-
`
`institution filings.
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`We declined to construe “pilot symbol” in the Decision to Institute,
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`stating that the broadest reasonable construction is apparent from the context
`
`of the claims and specification. Id. In its Response, Patent Owner proposed
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`10
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`Patent 7,269,127 B2
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`that “pilot symbol” should be construed to mean “a frequency domain
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`symbol for refining the calibration of a receiver to a transmitter.” PO Resp.
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`12–21. Petitioner “agrees with PO that a ‘pilot symbol’ as used in claim 1 is
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`a frequency-domain symbol.” Pet. Reply 3. We consider these statements
`
`in our analysis and Final Written Decision, but maintain our determination
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`from the Decision to Institute that no express construction of this term is
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`necessary.
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`Patent Owner also contends that claim 1’s recited “pilot/training
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`symbol inserter configured to insert pilot symbols into data blocks” should
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`be construed to mean that pilot symbols are inserted into individual data
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`blocks, but not in between, or among, data blocks. PO Resp. 16, 21–26; Tr.
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`41:21–42:2, 51:4–52:17. Petitioner contends that “pilot symbols can be
`
`inserted at any point into the data blocks,” i.e., within a data block or
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`between data blocks (Tr. 16:3–10, 68:21–69:11; see Pet. Reply 3–11).
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`Our interpretation of the disputed term begins with the language of the
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`claim. See Microsoft Corp. v. Proxyconn Inc., 789 F.3d 1292, 1299 (Fed.
`
`Cir. 2015). Claim 1 recites that pilot symbols are inserted “into data
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`blocks.” We construe claim 1’s plain language using the plural form of
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`“data blocks” to mean that pilot symbols may be inserted not only within a
`
`single data block, as Patent Owner contends, but also between one data
`
`block and another data block, as Petitioner contends.
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`Claims should also be read in light of the specification and teachings
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`in the underlying patent. Cuozzo, 793 F.3d at 1280; Microsoft, 789 F.3d at
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`11
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`IPR2014-01185
`Patent 7,269,127 B2
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`1298. Here, the specification also uses the plural form of data blocks in
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`explaining that “[t]ypically, pilot symbols may be inserted at any point in the
`
`data blocks.” Ex. 1001, 16:55–56, 7:28–29. There is no language in the
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`specification disclaiming the insertion of pilot symbols between data blocks.
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`We are persuaded that based on the claim’s usage of the plural “data
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`blocks,” which is supported by the description in the specification, the
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`broadest reasonable construction is “pilot/training symbol inserter
`
`configured to insert pilot symbols within, or between, one or more data
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`blocks,” and accordingly, does not exclude the insertion of pilot symbols
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`between two data blocks that are in a group of data blocks.
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`Patent Owner further contends that, for dependent claim 17 (which
`
`depends from claim 8 which in turn depends from claim 1), the recited
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`“transmitter comprising: an encoder . . .” should be construed to mean a
`
`single encoder. PO Resp. 28–29. Claim 1 uses the transitional term,
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`“comprising” between the preamble (“A transmitter of a communication
`
`system”) and the body of the claim. Ex. 1001, 16:52–53. Petitioner states
`
`that:
`
`It is well-settled that “‘comprising’ is a term of art used in claim
`language which means that the named elements are essential, but
`other elements may be added and still form a construct within the
`scope of the claim.” Genentech, Inc. v. Chiron Corp., 112 F.3d 495,
`501 (Fed. Cir. 1997). Thus, the claimed “encoder” is essential but
`other elements may be added, so the express language of claim 1
`does not preclude implementation with two encoders.
`
`
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`12
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`Patent 7,269,127 B2
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`Pet. Reply 20. We agree with Petitioner that “comprising” means including
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`the elements set forth in the body of the claim, but not excluding other
`
`elements, and, therefore, the broadest reasonable construction of “an
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`encoder” should not be limited to require only a single encoder. Baldwin
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`Graphic Sys., Inc. v. Siebert, Inc., 512 F.3d 1338, 1342 (Fed. Cir. 2008)
`
`(The Federal Circuit “has repeatedly emphasized that an indefinite article ‘a’
`
`or ‘an’ in patent parlance carries the meaning of ‘one or more’ in open-
`
`ended claims containing the transitional phrase ‘comprising.’”) (citation
`
`omitted).
`
`No other claim terms require express construction to resolve the issues
`
`raised in this inter partes review.
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`B. Level of Ordinary Skill in the Art
`
`Petitioner has not proposed a level of ordinary skill in the art. Patent
`
`Owner proposed that one of ordinary skill in the art would possess a
`
`“Bachelor’s degree in Electrical Engineering, Computer Science, or an
`
`equivalent field as well as at least 3–5 years of academic or industry
`
`experience in communications systems, with significant exposure to
`
`communication theory including modulation and digital signal processing.”
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`Ex. 2009 (Declaration of Dirk Hartogs, Ph.D.) ¶ 19. At the oral hearing,
`
`Petitioner stated there was no dispute between the parties as to the level of
`
`ordinary skill. Tr. 29:5–8.
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`We determine that an express definition of the level of ordinary skill
`
`is not required. The level of ordinary skill in the art can be reflected in the
`
`13
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`IPR2014-01185
`Patent 7,269,127 B2
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`cited prior art references. See Okajima v. Bourdeau, 261 F.3d 1350, 1355
`
`(Fed. Cir. 2001) (“[T]he absence of specific findings on the level of skill in
`
`the art does not give rise to reversible error where the prior art itself reflects
`
`an appropriate level and a need for testimony is not shown.”) (internal
`
`quotations omitted); In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir. 1995).
`
`Therefore, we find the level of ordinary skill in the art to be reflected in the
`
`cited references.
`
`C. Claims 1–3 and 5 – Asserted Obviousness over Schmidl and Arslan
`
`Petitioner contends claims 1–3 and 5 are unpatentable under
`
`35 U.S.C. § 103(a) as obvious over Schmidl and Arslan. Pet. 27–40. Claim
`
`1 is independent, and claims 2, 3, and 5 depend from claim 1.
`
`Schmidl (Exhibit 1002)
`
`Schmidl is titled, “Timing and Frequency Synchronization of OFDM
`
`Signals,” and, according to Petitioner, is the “primary reference” of its
`
`Petition, “directed at synchronization between wireless transmitters and
`
`receivers.”1 Pet. 10, 29. Schmidl discloses a method and apparatus for
`
`attaining rapid synchronization of a receiver to an OFDM signal. Ex. 1002,
`
`Title, Abstract, 8:30–35. Figure 1 of Schmidl is reproduced below.
`
`
`1 Schmidl is listed as a cited reference in the ’127 patent but was not
`specifically addressed by the Examiner as a basis for substantive rejections
`during prosecution of the application for the ’127 patent. Pet. 4; Ex. 1008.
`14
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`Figure 1 illustrates “typical” prior art OFDM transmitter 10. Ex. 1002,
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`1:39–42. Transmitter 10 receives a stream of data bits 12 which are
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`“immediately fed into” encoder 14. Id. at 1:42–44. Encoder 14 passes
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`sequences of symbols onto inverse fast Fourier transformer 16, producing
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`time-domain symbols that are modulated and form a composite OFDM
`
`signal that is passed to radio frequency transmitter 40 with antenna 52 for
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`transmission to a receiver. Id. at 2:1–6, 2:38–40, 2:58–3:24.
`
`Schmidl notes that, “timing and frequency synchronization of a
`
`receiver to an OFDM signal relies on the detection and analysis of a special
`
`OFDM training sequence that is included in the OFDM signal and preferably
`
`transmitted within a data frame.” Id. at 11:60–64. Figure 6 of Schmidl is
`
`reproduced below.
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`15
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`IPR2014-01185
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`Figure 6 illustrates the placement of an OFDM training sequence within a
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`data frame. Id. at 10:14–15, 11:66–67. Data frame 130 includes OFDM
`
`training sequence 132 with first OFDM training symbol 134 and second
`
`OFDM training symbol 136. Id. at 12:1–4. Schmidl states:
`
`One of the key advantages of the present invention over
`the prior art is that it enables a receiver to accurately
`synchronize to the symbol/frame timing of an OFDM signal
`with the reception of just one symbol, first OFDM training
`symbol 134.
`
`Ex. 1002, 14:27–31. Schmidl further discloses first OFDM training symbol
`
`134 has two identical halves. Ex. 1002, 12:49–59.
`
`Arslan (Ex. 1003)
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`
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`Arslan is titled, “Adaptive Channel Tracking Using Pilot Sequences,”
`
`and discloses synchronization of a channel estimator, or tracker, using a
`
`synchronization sequence, and retraining with known pilot symbols. Ex.
`
`16
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`1003, Abstract. Periodic retraining based on pilot symbols that are inserted
`
`in a frame structure can reduce error propagation. Id. at Abstract, 3:1–12,
`
`5:25–30. Figure 4 of Arslan is reproduced below.
`
`
`
`
`
`
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`Figure 4 depicts a frame structure, with synchronizing portion 0 to A
`
`using training symbols, information portions B–C, F–G, and J–K, and pilot
`
`portions D–E, H–I, and Y–Z. Ex. 1003, 6:7–11. The “pilot portions are
`
`interspersed between information portions” to allow retraining of an
`
`adaptive channel estimator. Id. at 6:11–14. The synchronizing portion of
`
`the frame is a series of predefined symbols 0 to A, which are the same for
`
`each received frame. Id. at 6:13–15. The pilot portions contain predefined
`
`symbols which may be used to retrain the channel estimator. Id. at 6:19–21.
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`Analysis
`
`Petitioner explains how the limitations of independent claim 1 are
`
`disclosed by Schmidl and Arslan. See Pet. 10–16, 27–35. For the recited
`
`encoder having a pilot/training symbol inserter configured to insert pilot
`
`symbols into data blocks and to combine training symbols with the data
`
`blocks, Petitioner contends Schmidl’s OFDM transmitter comprises an
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`17
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`encoder that “necessarily incorporates circuitry that inserts training symbols
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`in the frequency domain such that a training symbol in the time domain is
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`produced.” Pet. Reply 14–15 (citing Ex. 1036 (Supplemental Declaration of
`
`Dr. Zygmunt Haas) ¶ 16); see also Pet. 28 (citing Ex. 1002, Figs. 1, 6, 1:42–
`
`49, 1:63–67, 11:67–12:4). Petitioner additionally contends that “Arslan is
`
`directed at utilizing pilot symbols inserted into the data symbols to maintain
`
`synchronization between wireless transmitters and receivers” and “discloses
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`a frame structure having training symbols combined with information
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`portions (data symbols) and pilot portions inserted into (between)
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`information portions.” Pet. 29–30 (citing Ex. 1003, Fig. 4, 3:1–6); see also
`
`Pet. Reply 17.
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`Petitioner further contends Schmidl discloses the recited at least one
`
`modulator (Ex. 1002, 2:7–13, 2:23–25), each modulator having an inverse
`
`discrete Fourier transform stage and a cyclic prefix inserter (id. at Fig. 1,
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`2:1–10, 2:40–43), and each modulator outputting a frame structure
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`comprising a preamble structure and a data structure (id. at 11:59–12:27).
`
`For the recited preamble structure comprising at least one training symbol
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`and an enhanced training symbol, Petitioner contends that Figure 6 of
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`Schmidl discloses a first OFDM training symbol 134 corresponding to the
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`recited “enhanced training symbol,” and a second OFDM training symbol
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`136 corresponding to the recited “training symbol.” Pet. 33; Ex. 1002, 12:1–
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`4, 54–59.
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`Petitioner also contends Schmidl discloses the recited at least one
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`transmit antenna (id. at 3:7–13), corresponding to one of the at least one
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`modulators (id. at 3:13–23), and transmitting the frame structure output from
`
`the modulator (id. at Fig. 1), where the enhanced training symbol is a single
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`symbol (id. at 12:49–59, 14:26–30). See Pet. 10–16, 27–35.
`
`Patent Owner asserts, “[t]he combination of Schmidl and Arslan does
`
`not disclose a ‘pilot/training symbol inserter configured to insert pilot
`
`symbols into data blocks’ as required by independent claim 1.” PO Resp.
`
`11, 21–26. In particular, Patent Owner first argues that claim 1’s “pilot
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`symbols are frequency domain symbols inserted into a data block in the
`
`frequency domain,” and that Arslan’s pilot portions are time domain
`
`symbols, not frequency domain symbols. PO Resp. 13–17, 21–22. At his
`
`deposition, Patent Owner’s declarant testified that the phrase, “insert pilot
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`symbols into data blocks” excludes embodiments resulting in pilot symbols
`
`in the time domain. Pet. Reply 4 (citing Ex. 1034, 136:19–23).
`
`In its Reply, Petitioner “agrees with [Patent Owner] that a ‘pilot
`
`symbol’ as used in claim 1 is a frequency-domain symbol,” but adds that
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`“the term ‘pilot symbol’ appears in claim 1 only as part of the term ‘insert
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`pilot symbols into data blocks,’ and Petitioner disagrees with PO’s
`
`interpretation of this claim term.” Pet. Reply 3. Petitioner asserts OFDM
`
`pilot symbols can also occur in the time domain, because Figure 6 of the
`
`’127 patent depicts data structures in the time domain and the specification
`
`confirms that, “[a]lthough omitted from FIG. 6 for simplicity, pilot symbols
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`may also be intermittently inserted into the data symbols 80 by the
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`pilot/training symbol inserter, as discussed above.” Ex. 1001, Fig. 6, 11:44–
`
`47. Patent Owner’s expert testified that Figure 6 does depict symbols in the
`
`time domain. Pet. Reply 8 (citing Ex. 1034, 117:11–14).
`
`We agree with Petitioner. The parties do not dispute that claim 1’s
`
`insertion of pilot symbols occurs in the frequency domain. PO Resp. 15–16;
`
`Pet. Reply 3. After insertion, the symbols are then converted by the IDFT
`
`from the frequency domain to the time domain. Ex. 1001, 7:22–25, 8:1–6.
`
`Patent Owner’s declarant testified that pilot symbols inserted “into” data
`
`blocks in the frequency domain do not appear in the time domain. Ex. 1034
`
`(Deposition of Dirk Hartogs, Ph.D.), 124:4–11, 132:3–7. At the oral
`
`hearing, Patent Owner asserted likewise (Tr. 44:3–12, 44:20–45:3, 47:14–
`
`19), but also admitted that pilot symbols inserted “between” data blocks in
`
`the frequency domain can appear in the time domain. Tr. 49:4–13. As set
`
`forth above, we have construed claim 1’s limitation of “insert pilot symbols
`
`into data blocks” to include insertion of such symbols between data blocks.
`
`See Section II.A.
`
`In addition, the ’127 patent specifies that pilot symbols can exist in
`
`the time domain. Ex. 1001, Fig. 6, 11:44–47. Patent Owner’s declarant’s
`
`testimony confirms that, “everything happening in Figure 6 is . . . in the
`
`time domain,” Ex. 1034, 130:2–10. We agree with Petitioner’s contention
`
`that the specification indicates the structure depicted in Figure 6 could
`
`include pilot symbols. See Ex. 1001, Fig. 6, 11:44–47. Accordingly,
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`pursuant to the ’127 patent and our construction of “insert pilot symbols into
`
`data blocks,” we determine that as contended by Petitioner, pilot symbols
`
`may appear in both the frequency domain prior to being converted by the
`
`IDFT, and in the time domain after the transform.
`
`Second, Patent Owner argues that Arslan’s time domain pilot portions
`
`are inserted only in between data blocks, and not within an individual data
`
`block, as allegedly required by claim 1. PO Resp. 22–26. In its Reply,
`
`Petitioner contends Patent Owner’s argument is based on an improper
`
`proposed construction of “insert pilot symbols into data blocks,” limiting
`
`insertion into a discrete, single data block. Pet. Reply 3, 11. Petitioner
`
`states Arslan’s frame structure contains “pilot symbols subsequently
`
`interspersed among data symbols.” Pet. Reply 15–16.
`
`We agree with Petitioner because we have determined that Patent
`
`Owner’s proposed construction of “insert pilot symbols into data blocks” is
`
`too narrow, and that the broadest reasonable interpretation includes the
`
`insertion of pilot symbols within, or between, one or more data blocks. See
`
`Section II.A supra. Arslan teaches that pilot symbols are so “inserted in the
`
`sequence of a frame” and “interspersed between information portions.” Ex.
`
`1003, Fig. 4, 7:40–41, 6:10–13. We are, thus, persuaded that Schmidl and
`
`Arslan teach or suggest the recited pilot/training symbol inserter configured
`
`to insert pilot symbols into (including between) data blocks.
`
`Petitioner also describes why it would have been obvious to one of
`
`ordinary skill in the art to combine Schmidl with Arslan. Petitioner states
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`21
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`that “both Schmidl and Arslan are directed at improving synchronization
`
`between a wireless transmitter and a wireless receiver, and disclose frame
`
`structures including information for the same.” Pet. 16. In particular,
`
`Schmidl discloses an encoder that inserts training symbols in the frequency
`
`domain, to form training symbols in the time domain. Pet. Reply 13, 17
`
`(citing Ex. 1036 ¶ 21); see Ex. 1002, 2:7–17. Arslan discloses a frame
`
`structure in the time domain containing pilot symbols interspersed among
`
`data symbols. Pet. Reply 16–17 (citing Ex. 1036 ¶¶ 20, 22). Petitioner
`
`further states:
`
`[I]t would have been obvious to use pilot symbols as
`separate time domain symbols for tracking time variations
`to calibrate or synchronize the receiver to the transmitter
`by using time-domain pilot symbols in Schmidl’s system.
`. . [citing to Supplemental Declaration of Dr. Zygmunt
`Haas ¶ 22.] As discussed above, Schmidl discloses
`inserting symbols in the frequency domain for an OFDM
`system, for calibration and synchronization. See id. It
`would have been obvious to create those time-domain
`pilot symbols in the same manner as the time-domain
`training symbols are created in Schmidl’s encoder – that
`is, by inserting blocks of known pilot symbols in the
`frequency domain that would result in time-domain pilot
`symbols. See id. It would be obvious to a POSA that the
`same circuitry in Schmidl’s encoder 14 used to insert
`training symbols would be used to insert pilot symbols,
`resulting in the claimed “pilot/training symbol inserter
`configured to insert pilot symbols into data blocks.” See
`id.
`
`
`Pet. Reply 17–18; see Pet. 16, 29–30.
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`22
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`We are persuaded that there is a preponderance of evidence showing
`
`Schmidl and Arslan teach or suggest the limitations of claim 1, and that
`
`Petitioner has provided articulated reasoning supported by rational
`
`underpinnings for combining the references. KSR Int’l Co. v. Teleflex Inc.,
`
`550 U.S. 398, 418 (2007). Based on the Petition, the Haas Declarations, and
`
`the record before us, we are persuaded that Petitioner has shown by a
`
`preponderance of the evidence that claim 1 is obvious over Schmidl and
`
`Arslan.
`
`Claims 2, 3, and 5 all depend directly or indirectly from claim 1 (Pet.
`
`35–40), and recite further features of the data structure, enhanced training
`
`symbol, and training block of the enhanced training symbol, respectively.
`
`Ex. 1001, 17:4–16, 17:22–25. Petitioner provides explanations of how
`
`Schmidl discloses the recited features of claims 2 and 3; and, with respect to
`
`claim 5, how “it naturally follows” that Schmidl’s training interval, which
`
`has two identical halves each with a given number of samples, comprises
`
`twice the given number of samples. Pet. 35–40 (citing Ex. 1009, 64–65
`
`(Declaration of Zygmunt J. Haas, Ph.D., element 5.1)); Ex. 1002, Figs. 4, 6,
`
`1:42–47, 2:38–43, 12:49–13:9. Patent Owner does not attempt to refute any
`
`of Petitioner’s specific contentions as to claims 2, 3, and 5.
`
`Based on the Petition, the Haas Declarations, and the remainder of the
`
`entire record after trial, we conclude that Petitioner has proved by a
`
`preponderance of the evidence that dependent claims 2, 3, and 5 are obvious
`
`over Schmidl and Arslan.
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`23
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`D. Claims 4 and 6–10: Asserted Obviousness Over Schmidl, Arslan
`and Kim
`
`Petitioner contends claims 4 and 6–10 are unpatentable under
`
`35 U.S.C. § 103(a) as obvious over Schmidl, Arslan, and Kim. Pet. 40–46.
`
`Kim (Exhibit 1004)
`
`Kim is titled, “Timing and Frequency Offset Estimation Scheme for
`
`OFDM Systems by Using an Analytic Tone,” and discloses the use of an
`
`analytic signal, or tone, to calculate timing offset and frequency offset
`
`estimations in OFDM systems. Pet. 16; Ex. 1004, 1:7–10, 5:49–52. Kim
`
`cites to an article by the Schmidl inventors. Ex. 1004, 1:53–60.
`
`Figure 8 of Kim is reproduced below.
`
`
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`
`
`Figure 8 depicts a data structure and, in particular, a signal
`
`architecture for a wireless network in an OFDM system. Ex. 1004, 2:22–24,
`
`5:31–32. Guard intervals G1 through G5 are provided at the beginning of
`
`each of data symbol D1 and training symbols R1 through R4, each of which
`
`also contains four sections. Id. at 2:24–26. In each of the symbols, the
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`24
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`guard interval is N/4, where N=64, such that the length of the guard interval
`
`is 16. Id. at 2:32–34.
`
`Analysis
`
`Claims 4 and 6–10 all depend, directly or indirectly, from claim 1, and
`
`recite further features of the data block, the training block of
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