Ericsson Inc.v.Intellectual Ventures II LLC

Patent Trial and Appeal Board

Jan 21, 2016

10264546 (P.T.A.B. Jan. 21, 2016)

Trials@uspto.gov Paper 35
571-272-7822 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
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I. INTRODUCTION
Ericsson Inc. and Telefonaktiebolaget LM Ericsson (“Petitioner”)
filed a Petition requesting an inter partes review of claims 1–10, 17, 20, 21,
23, and 24 of U.S. Patent No. 7,269,127 (Ex. 1001, “the ’127 patent”).
Paper 2 (“Pet.”). Intellectual Ventures II LLC (“Patent Owner”) filed a
Preliminary Response. Paper 10 (“Prelim. Resp.”). On January 28, 2015,
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.”).
After institution of trial, Patent Owner filed a Patent Owner Response
(Paper 19, “PO Resp.”), to which Petitioner filed a Reply (Paper 22, “Pet.
Reply”). Patent Owner filed a Motion for Observations on the Cross-
Examination of Zygmunt Haas, Ph.D. (Paper 27), to which Petitioner
responded (Paper 31). An oral hearing was held on October 21, 2015. The
transcript of the consolidated hearing has been entered into the record.
Paper 34 (“Tr.”).
The Board has statutory authority under 35 U.S.C. § 6(c). In this
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.
A. Related Proceedings
According to Petitioner, the ’127 patent is involved in the following
district court cases: Intellectual Ventures I LLC, et al. v. AT&T Mobility
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LLC et al., 1-13-cv-01668 (D. Del.); Intellectual Ventures I LLC, et al. v.
Leap Wireless Int’l et al., 1-13-cv-01669 (D. Del.); Intellectual Ventures I
LLC, et al. v. Nextel Operations et al., 1-13-cv-01670 (D. Del.); Intellectual
Ventures I LLC, et al. v. T-Mobile USA Inc. et al., 1-13-cv-01671 (D. Del.);
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)
Communication Systems.” The subject matter of the challenged claims of
the ’127 patent relates generally to increased operating efficiency in wireless
communication systems, and, in particular, to preamble structures in multi-
input, multi-output (MIMO) wireless communication systems with two or
more transmit and receive antennas, and single-input, single-output (SISO)
wireless systems with one transmit and one receive antenna. Ex. 1001,
1:29–40, 3:21–24. In MIMO wireless communications systems, signals are
pre-processed to avoid interference from other signals in common
communications channels or paths. Id. at 1:54–57. Pre-processing
techniques can include using frame structures, which are comprised of
preamble structures and data structures. Id. at 1:58–63. An efficient
preamble structure for use in wireless communications systems should
provide for both synchronization of data symbols and estimation of
parameters such as noise variance and other parameters. Id. at 2:56–62.
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Figure 1 of the ’127 patent is reproduced below.

Figure 1 is a block diagram of exemplary MIMO communication system 10.
Id. at 4:3–4, 39–40. MIMO system 10 may be implemented as a wireless
system for transmission from transmitter 14 across wireless channel 12 to
receiver 16. Id. at 4:43–46, 5:8–10. Transmitter 14 includes encoder 18,
which typically encodes data and/or other types of signals received, for
example, from data source 20. Id. at 5:13–15.
A MIMO communication system may employ various signal
modulation and demodulation techniques, including orthogonal frequency
division multiplexing (OFDM). Id. at 4:58–62. Modulators 24-1 to 24-Q
modulate signals for transmission using, for example, OFDM techniques.
Id. at 5:31–35. In particular, modulators 24 include an inverse discrete
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Fourier transform (IDFT) stage that receives a parallel format of training
blocks and data blocks and converts them from the frequency domain to the
time domain. Id. at 8:1-5. Within the modulator, the converted signals are
input to an amplifier and then to transmit antennas 26-1 to 26-Q, which
transmit the signals across channel 12. Id. at 8:31–34.
Data or information (e.g., voice, video, audio, text) can be transmitted
as data symbols organized into data structures. Id. at 1:64–2:1. Training
symbols are typically added as prefixes to data structures, to enable
synchronization between transmitters and receivers of a communications
system. Id. at 2:10–14. These training symbols can be referred to as
preambles and are part of the preamble structures. Id. at 2:14–15. The
preamble structure can contain an enhanced training symbol, which is
divided into sections to perform synchronization and channel parameter
estimation functions. Id. at 11:2–8.
Pilot symbols “have the same structure as preambles. However,
instead of being placed as a prefix to the data structure, the pilot structures
are periodically arranged within groups of data symbols.” Id. at 2:17–22.
Figure 2 of the ’127 patent is reproduced below.
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Figure 2 is a block diagram of encoder 18. Id. at 4:5–6. Encoder 18
includes pilot training symbol inserter 46, which “provides pilot blocks and
training blocks that are inserted into (or combined with) the data blocks” by
adders 44-1 to 44-Q. Id. at 7:14–25. The pilot blocks, or pilot symbols, are
“transmitted with data blocks to calibrate (i.e., synchronize) the receiver 16
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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Figure 6 is a diagram of frame structures 68 in signal structure 66. Ex. 1001,
10:50–55. Each of frame structures 68 includes preamble structure 70 and
data structure 72. Id. at 10:57–59. Preamble structure 70 includes training
symbol 74, and enhanced training symbol 79 located at the beginning of
preamble structure 70. Id. at 10:62–11:5. Training block 78 of enhanced
training symbol 79 is divided into several sections, for synchronization and
for channel parameter estimation. Id. at 11:5–8. Data structure 72 includes
one or more data symbols 80, which in turn include cyclic prefix 76 and data
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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Illustrative Claim
Claims 1–10 and 17 are the subject of the trial. Claim 1 is
independent and is reproduced as follows.
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

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.

Id. at 16:52–17:3.

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C. Prior Art Supporting the Instituted Challenges
The following four prior art references were asserted in the instituted
grounds.
Reference Title Date Ex. No.
Schmidl US 5,732,113 Mar. 24, 1998 (filed
June 20, 1996)
Ex. 1002
Arslan US 6,411,649 June 25, 2002 (filed
Oct. 20, 1998)
Ex. 1003
Kim US 7,012,881 Mar. 14, 2006 (filed
Dec. 29, 2000)
Ex. 1004
Heiskala US 6,298,035 Oct. 2, 2001 (filed
Dec. 21, 1999)
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
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II. ANALYSIS
A. Claim Construction
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.
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
symbol” as “a training symbol, comprising a plurality of sections including
repeated sequences, and providing at least a synchronization function.”
Paper 11, 8–9. Neither party contests that construction in their post-
institution filings.
We declined to construe “pilot symbol” in the Decision to Institute,
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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that “pilot symbol” should be construed to mean “a frequency domain
symbol for refining the calibration of a receiver to a transmitter.” PO Resp.
12–21. Petitioner “agrees with PO that a ‘pilot symbol’ as used in claim 1 is
a frequency-domain symbol.” Pet. Reply 3. We consider these statements
in our analysis and Final Written Decision, but maintain our determination
from the Decision to Institute that no express construction of this term is
necessary.
Patent Owner also contends that claim 1’s recited “pilot/training
symbol inserter configured to insert pilot symbols into data blocks” should
be construed to mean that pilot symbols are inserted into individual data
blocks, but not in between, or among, data blocks. PO Resp. 16, 21–26; Tr.
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
between data blocks (Tr. 16:3–10, 68:21–69:11; see Pet. Reply 3–11).
Our interpretation of the disputed term begins with the language of the
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
blocks.” We construe claim 1’s plain language using the plural form of
“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.
Claims should also be read in light of the specification and teachings
in the underlying patent. Cuozzo, 793 F.3d at 1280; Microsoft, 789 F.3d at
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1298. Here, the specification also uses the plural form of data blocks in
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
specification disclaiming the insertion of pilot symbols between data blocks.
We are persuaded that based on the claim’s usage of the plural “data
blocks,” which is supported by the description in the specification, the
broadest reasonable construction is “pilot/training symbol inserter
configured to insert pilot symbols within, or between, one or more data
blocks,” and accordingly, does not exclude the insertion of pilot symbols
between two data blocks that are in a group of data blocks.
Patent Owner further contends that, for dependent claim 17 (which
depends from claim 8 which in turn depends from claim 1), the recited
“transmitter comprising: an encoder . . .” should be construed to mean a
single encoder. PO Resp. 28–29. Claim 1 uses the transitional term,
“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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Pet. Reply 20. We agree with Petitioner that “comprising” means including
the elements set forth in the body of the claim, but not excluding other
elements, and, therefore, the broadest reasonable construction of “an
encoder” should not be limited to require only a single encoder. Baldwin
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.
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.”
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.
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
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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.
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Figure 1 illustrates “typical” prior art OFDM transmitter 10. Ex. 1002,
1:39–42. Transmitter 10 receives a stream of data bits 12 which are
“immediately fed into” encoder 14. Id. at 1:42–44. Encoder 14 passes
sequences of symbols onto inverse fast Fourier transformer 16, producing
time-domain symbols that are modulated and form a composite OFDM
signal that is passed to radio frequency transmitter 40 with antenna 52 for
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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Figure 6 illustrates the placement of an OFDM training sequence within a
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)
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.
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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.

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.
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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encoder that “necessarily incorporates circuitry that inserts training symbols
in the frequency domain such that a training symbol in the time domain is
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
a frame structure having training symbols combined with information
portions (data symbols) and pilot portions inserted into (between)
information portions.” Pet. 29–30 (citing Ex. 1003, Fig. 4, 3:1–6); see also
Pet. Reply 17.
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,
2:1–10, 2:40–43), and each modulator outputting a frame structure
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
and an enhanced training symbol, Petitioner contends that Figure 6 of
Schmidl discloses a first OFDM training symbol 134 corresponding to the
recited “enhanced training symbol,” and a second OFDM training symbol
136 corresponding to the recited “training symbol.” Pet. 33; Ex. 1002, 12:1–
4, 54–59.
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Petitioner also contends Schmidl discloses the recited at least one
transmit antenna (id. at 3:7–13), corresponding to one of the at least one
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
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
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
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
“the term ‘pilot symbol’ appears in claim 1 only as part of the term ‘insert
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
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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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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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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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.

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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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 the enhanced
training symbol, and the cyclic prefix of the enhanced training symbol,
including the number of samples in (i) data blocks, (ii) training blocks of
training symbols, (iii) training blocks of enhanced training symbols, (iv)
cyclic prefixes, and (v) sections of training symbols. Ex. 1001, 17:17–21,
26–41. Petitioner contends that Kim discloses that each data block includes
64 samples. Pet. 40–41, 43–44. Petitioner provides explanations of how
Schmidl and Kim disclose the recited features of claims 4 and 6–10. Pet.
40–46; Ex. 1002, Figs. 4, 6, 4:55–63; Ex. 1004, Fig. 8, 2:22–36. With
respect to claim 4, Petitioner also contends:
[I]t would have been obvious for one of ordinary skill in the art
to apply the known techniques of dividing the training symbols
into a number of sections with each section including a number
of samples, as taught by Kim, to the known training symbols of
Schmidl to yield predictable results.

Pet. 40–41. With respect to claim 9, Petitioner states that because Kim
discloses a training block having 16 samples divided equally among four
equal sections, it “naturally follows” that each section contains an equal
number of samples. Pet. 44–45 (citing Ex. 1009, 79–81 (element 9.1)).
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Patent Owner does not attempt to refute any of Petitioner’s specific
contentions as to claims 4 and 6–10, and instead argues only that “Kim does
not mention the use of pilot symbols and therefore cannot overcome the
deficiencies of Schmidl and Arslan.” PO Resp. 28. We are persuaded that
there is a preponderance of evidence showing Schmidl, Arslan, and Kim
teach or suggest the limitations of dependent claims 4 and 6–10, and that
Petitioner has provided articulated reasoning supported by rational
underpinnings for combining the references. Based on the Petition, the Haas
Declarations, and the record before us, we conclude that Petitioner has
proved by a preponderance of the evidence that dependent claims 4 and 6–
10 are obvious over Schmidl, Arslan, and Kim.
E. Claim 17: Asserted Obviousness over Schmidl, Arslan, Kim, and
Heiskala
Petitioner contends claim 17 is unpatentable under 35 U.S.C. § 103(a)
as obvious over Schmidl, Arslan, Kim, and Heiskala. Pet. 46–48.
Heiskala (Ex. 1006)
Heiskala is titled, “Estimation of Two Propagation Channels in
OFDM,” and discloses an OFDM system with two transmitters to transmit
training symbols over separate channels. Ex. 1006, Abstract, 1:5–9, 6:5–7,
Fig. 4. Schmidl is a cited reference in Heiskala; Figure 1 of Heiskala, which
is “a block diagram of a typical OFDM transmitter according to the prior
art” (id. at 2:49–50), appears to be a copy of Figure 1 of Schmidl.
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Analysis
Claim 17 depends indirectly from claim 1, and further recites two
modulators and “transmit antennas,” and first and second training blocks
corresponding to the transmit antennas. Ex. 1001, 18:4–10. Petitioner
contends that Heiskala discloses using two OFDM transmitters, each
including a modulator and an antenna. Pet. 46–48. Petitioner further
contends that:
both Schmidl and Heiskala are directed at OFDM transmitters
for transmitting training symbols, and, furthermore, Heiskala
examines Schmidl’s transmitter and proposes improvements to
the same. . . . [citing to Haas Decl., ¶¶ 60–61]. Accordingly, it
would have been obvious for one of ordinary skill in the art to
apply the known technique of using two transmitters to transmit
training symbols, as taught by Heiskala, to the known OFDM
system of Schmidl, to yield predictable results of transmitting
training symbols using two OFDM transmitters, each having a
modulator and an antenna.

Pet. 47. Patent Owner argues claim 17 “requires a single encoder” coupled
to two modulators and two antennas “as demonstrated by the plain language
of the claim as well as the specification. In contrast, Petitioners’ proposed
combination results in a system with two encoders . . . .” PO Resp. 28–29;
see id. at 30–34.
In its Reply, Petitioner contends the claim is not limited to a single
encoder, and that PO improperly reads Figure 1 of the ’127 patent, which
depicts one encoder, into the limitations of the claim. Pet. Reply 19–22. We
agree with Petitioner, as the plain language of claim 17 is not limited to a
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single encoder. Rather, as discussed above, the preamble of independent
claim 1, from which claim 17 ultimately depends, transitions to the body of
the claim with the word “comprising.” Thus, claim 1’s recitation of “an
encoder” does not exclude other elements, such as more than one encoder.
See section II.A. supra.
At oral hearing, Patent Owner stated, “claim 17 requires two
modulators coupled to a single encoder.” Tr. 65:2–3. Claim 17, however,
does not recite coupling of an encoder to modulators. Pet. Reply 20–21
(citing Ex. 1034, 60:10–16).
We are persuaded that there is a preponderance of evidence showing
Schmidl, Arslan, Kim, and Heiskala teach or suggest the limitations of
dependent claim 17, and that Petitioner has provided articulated reasoning
supported by rational underpinnings for combining the references. Based on
the record before us, we conclude that Petitioner has proved by a
preponderance of the evidence that dependent claim 17 is obvious over
Schmidl, Arslan, Kim, and Heiskala.
CONCLUSION
Petitioner has demonstrated by a preponderance of the evidence the
unpatentability of claims 1, 2, 3, and 5 of the ’127 patent as obvious over
Schmidl and Arslan; claims 4 and 6–10 as obvious over Schmidl, Arslan and
Kim; and claim 17 as obvious over Schmidl, Arslan, Kim, and Heiskala.
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III. ORDER
Accordingly, it is
ORDERED that, based on Petitioner’s showing by a preponderance of
the evidence, claims 1–10 and 17 of the ’652 patent are unpatentable.
This is a Final Written Decision. Parties to the proceeding seeking
judicial review of this decision must comply with the notice and service
requirements of 37 C.F.R. § 90.2.

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PETITIONER:
J. Andrew Lowes
andrew.lowes.ipr@haynesboone.com

David M. O’Dell
david.odell.ipr@haynesboone.com

John Russell Emerson
russell.emerson.ipr@haynesboone.com

Clint Wilkins
clint.wilkins.ipr@haynesboone.com

PATENT OWNER:
Lori Gordon
lgordon-PTAB@skgf.com

Michael Specht
mspecht-PTAB@skgf.com

Ryan Richardson
rrichardson-PTAB@skgf.com

James Hietala
jhietala@intven.com

Tim Seeley
tim@intven.com

Byron Pickard
bpickard-PTAB@skgf.com