Fraunhofer-Gesellschaft zur Forderung der angewandten Forschung e.V.

Patent Trials and Appeals Board

Mar 11, 2021

IPR2018-00682 (P.T.A.B. Mar. 11, 2021)

Trials@uspto.gov Paper No. 25
571-272-7882 Entered: March 11, 2021

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

SIRIUS XM RADIO INC.
Petitioner,

v.

FRAUNHOFER-GESELLSCHAFT ZUR FÖRDERUNG DER
ANGEWANDTEN FORSCHUNG E.V.,
Patent Owner.
____________

Case IPR2018-00682
Patent 6,931,084 B1
____________

Before JEFFREY S. SMITH, STACEY G. WHITE, and GARTH D. BAER,
Administrative Patent Judges.

BAER, Administrative Patent Judge.

DECISION
Denying Institution of Inter Partes Review
37 C.F.R. § 42.108

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Patent 6,931,084 B1
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Sirius XM Radio Inc. (“Petitioner”) filed a Petition (Paper 1, “Pet.”)
requesting inter partes review of claims 1–3 of U.S. Patent No. 6,931,084
(Ex. 1001, “the ʼ084 patent”). Patent Owner Fraunhofer-Gesellschaft zur
Förderung der angewandten Forschung e.V. (“Patent Owner”) filed a
Preliminary Response (Paper 8, “Prelim. Resp.”). In our Institution
Decision, we denied institution based on Petitioner’s failure to identify
Sirius XM Holdings Inc. (“Holdings”) as an RPI in this proceeding. Paper
12, 7. We also denied Petitioner authorization to amend its mandatory
notice to add Holdings without changing the Petition’s filing date. Id.
Petitioner requested Rehearing (Paper 13), which we granted (Paper 24),
finding Petitioner could add Holdings as an RPI without changing the
Petition’s filing date.
We now turn to the merits of the Petition. Pursuant to 35 U.S.C.
§ 314(a), an inter partes review may not be instituted unless “the
information presented in the petition . . . shows that there is a reasonable
likelihood that the petitioner would prevail with respect to at least one of the
claims challenged in the petition.” Having considered the Petition and the
Preliminary Response, we determine that there is not a reasonable likelihood
that Petitioner would prevail in establishing that claims 1–3 of the ʼ084
patent are unpatentable. Therefore, we decline to institute inter partes
review.
I. BACKGROUND
II. RELATED PROCEEDINGS
The parties assert that the ʼ084 patent is involved in Fraunhofer-
Gesellschaft zur Förderung der angewandten Forschung e.V. v. Sirius XM
Radio Inc., 1:17-cv-00184 (D. Del. Feb. 22 2017).
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III. THE ʼ084 PATENT
The ʼ084 patent is directed, in general, to “echo phase offset
correction in a multi-carrier demodulation system.” Ex. 1001, Abstract,
Claim 1. This technology is useful for a mobile receiver of broadcast digital
data. Id. at 1:20–23. The broadcast may be performed over a radio
frequency (RF) signal, modulated on a carrier frequency. Pet. 10–11. Phase
modulation (PM) in particular is useful for transmitting digital data on a
modulated carrier wave. One PM example is Quadrature Phase Shift Keying
(QPSK) that uses four waveforms to represent two-bit symbols. Pet. 13,
Fig. 2; Prelim. Resp. 22, 24–25. Digital coding using PM can also map a bit
symbol to a difference between the phases of multiple waveforms in a
signal. Ex. 1001, 2:57–62; Pet. 20–21; Prelim. Resp. 21–23. In Differential
Quadrature Phase Shift Keying (DQSPK) mapping, two bits are encoded as
the difference of 0, 90, 180, or 270 degrees between two symbols. Ex. 1001,
2:57–62. For example, the bits 01 can be represented as a symbol of 90
degrees phase followed by a symbol of 180 degrees phase, in which the
difference in phases between the two symbols is 90 degrees. Prelim.
Resp. 21–23.
In a differential phase keying coding system, multiple symbols from a
variety of sources are compared at a receiver to determine the difference
between their phases. In a time domain multi-carrier modulation (MCM)
approach, the symbols may be presented sequentially in time on one
subcarrier frequency of multiple subcarriers. Prelim. Resp. 21–22. An
alternative approach to time domain coding is frequency domain coding,
shown in Figure 1 of the ʼ084 patent. In a frequency domain MCM
embodiment, different symbols are transmitted simultaneously on different
subcarriers having different frequencies. Ex. 1001, 1:30–36, 5:10–12, 36–
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40. The difference between two symbols that makes up the coding of two
bits occurs between symbols on different subcarriers. Pet. 17; Prelim.
Resp. 22–23.
The claimed method addresses the problem of erroneous phase offsets
in the received and decoded signals, as may be caused by echoes in the
received signal. Pet. 1–2, 18–22. Figure 5 of the ʼ084 patent is reproduced
below.

Figure 5 illustrates a “schematic block diagram of an embodiment of an echo
phase offset correction device according to the present invention.”
Ex. 1001, 6:65–67.
IV. ILLUSTRATIVE CLAIM
Of the challenged claims, only claim 1 (reproduced below) is
independent.
1. A method of performing an echo phase offset correction in a
multi-carrier demodulation system, comprising the steps of:
differential phase decoding phase shifts based on a phase
difference between simultaneous carriers having different
frequencies;
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determining an echo phase shift offset for each decoded phase
shift by eliminating phase shift uncertainties related to the
transmitted information from said decoded phase shift;
averaging said echo phase offsets in order to generate an
averaged offset;
correcting each decoded phase shift based on said averaged
offset; and
further comprising a step of comparing an absolute value of a
symbol associated with a respective decoded phase shift with a
threshold, wherein only phase shifts having associated
therewith symbols having an absolute value exceeding said
threshold are used in said step of averaging said echo phase
offsets.
Ex. 1001, 15:16–35.
V. ASSERTED GROUNDS OF UNPATENTABILITY
Petitioner asserts the following grounds of unpatentability. Pet. 6.
Claims Challenged 35 U.S.C. §1 References/Basis
1–3 103 Tsujishita2, Moose 19903
1–3 103 Tsujishita, Moose 1990, Koslov4

1 The Leahy-Smith America Invents Act (“AIA”) amended 35 U.S.C. § 103.
See Pub. L. No. 112-29, 125 Stat. 284, 285–88 (2011). As the application
that issued as the ’299 patent was filed before the effective date of the
relevant amendments, the pre-AIA version of § 103 applies.
2 U.S. Patent No. 6,341,123 B1 (issued Jan. 22, 2002) (Ex. 1006,
“Tsujishita”).
3 P.H. Moose, “Differential Modulation and Demodulation of Multi-
Frequency Digital Communications Signals” (1990) (Ex. 1007, “Moose
1990”).
4 U.S. Patent No. 5,940,450 A (issued Aug. 17, 1999) (Ex. 1009, “Koslov”)
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VI. ANALYSIS
A. CLAIM CONSTRUCTION
We conclude no express claim construction is necessary for our
determination of whether to institute inter partes review of the challenged
claims. See Nidec Motor Corp. v. Zhongshan Broad Ocean Motor Co., 868
F.3d 1013, 1017 (Fed. Cir. 2017) (“[W]e need only construe terms ‘that are
in controversy, and only to the extent necessary to resolve the
controversy.’”) (quoting Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200
F.3d 795, 803 (Fed. Cir. 1999)).
VII. ASSERTED PRIOR ART
VIII. Tsujishita (Ex. 1006)
Tsujishita discloses a:
digital audio broadcasting receiver [that] comprises a phase error
detector for detecting a phase error from data from a differential
demodulator, an average value processing unit for determining
the average value of phase errors, a memory for storing the phase
errors of the carriers outputted from the phase error detector, and
a phase error correcting unit which excludes a phase error whose
sign is opposite to that of the average values among the phase
errors stored in the memory.
Ex. 1006, Abstract. Figure 1 of Tsujishita illustrates a block diagram of the
digital audio broadcasting receiver (id. at 6:26–29), with further figures
illustrating additional variant embodiments, including a fourth embodiment
at Figure 8, reproduced below.
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Tsujishita particularly describes a system for correcting phase errors
associated with frequency deviations in “differentially modulated data.”
Figure 19 illustrates the differentially modulated data as divided into the four
quadrants of the complex plane, in accordance with DQSPK, with phase
errors moving data into an adjacent quadrant. Ex. 1006, 2:66–3:25.
IX. Moose 1990 (Ex. 1007)
Moose 1990 is a paper that describes “Multi-Frequency Modulation”
and demodulation of DQSPK signals. Ex. 1007, 273. The differential
decoding of QSPK symbols in Moose 1990 occurs “in the frequency
domain” among bits transmitted in different frequency bands. Id. at 275.
X. Koslov (Ex. 1009)
Koslov discloses a system for recovering symbols including QPSK-
modulated symbols in a received carrier signal that contains a phase error or
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frequency error, using a variety of techniques. Ex. 1009, code [57].
Koslov’s Figure 2 is reproduced below.

Figure 2 illustrates a carrier recovery circuit. Id. at 2:4
XI. ANALYSIS
1. Obviousness over Tsujishita and Moose 1990
Petitioner asserts that claims 1–3 would have been obvious over
Tsujishita and Moose 1990. Pet. 31. On the current record, for the reasons
explained below, we find Petitioner has not made an adequate showing that
this combination of references discloses or makes obvious the “correcting”
step recited in claim 1.
XII. “correcting each decoded phase shift based on said averaged
offset”
Petitioner asserts that Tsujishita discloses “correcting each decoded
phase shift based on said averaged offset,” as required in claim 1. Pet. 38–
39. We disagree. Petitioner cites as support a passage from Tsujishita’s
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column 2, lines 31–37, which states that “frequency tuning control means 13
operates . . . by controlling the frequency of the local oscillator 4 in a matter
that this phase error ξ becomes small.” Id. at 39. Figure 8 of Tsujishita is
reproduced below.

Figure 8 illustrates a feedback loop such that averaging unit 40 outputs
directly to Frequency Tuning Control Unit 13, which in turn outputs directly
to Local Oscillator 4. Ex. 1006, Fig. 8, 7:27, 10:30–33, 10:67–11:5. In
particular, Tsujishita explains as follows:
In step 214, the averaging unit 40 performs averaging processing
with respect to the phase error which was not determined to be
in error and the restored phase error. The result is outputted to
the frequency tuning control means 13 as the phase error. As a
result, it is possible to control the local oscillator 4 . . . .
Id. at 10:67–11:5. Thus, Tsujishita’s discloses correcting a received
modulated signal using local oscillator 4 and mix 3, which are upstream
from differential demodulator 11 and Viterbi demodulator 14. See id. at
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Fig. 8. Thus, the phase error correction occurs before “the phase of each
transmission carrier subjected to quadrature phase shift keying (QPSK) is
detected” at discrete Fourier transform processing (DFT) means 10. Id. at
1:41–44. The error correction occurs upstream of differential demodulator
11 where “modulated phases . . . of two transmitted symbols which are
timewise adjacent to each other are compared, and processing (differential
demodulation) for outputting a phase shift in the mean time is effected.” Id.
at 1:43–48. It occurs before the “data subjected to differential demodulation
is then outputted to the Viterbi decoder 14 in accordance with a rule on the
order of carriers used in modulation on the transmitting side.” Id. at 1:48–
51. As such, Tsujishita does not correct a “decoded” signal as claim 1
requires. Rather, it corrects a received signal before it is decoded.
Given this deficiency, on this record and for the purposes of this
Decision, Petitioner has not shown a reasonable likelihood that it would
prevail in establishing claims 1–3 would have been obvious over Tsujishita
and Moose 1990.
XIII. Obviousness over Tsujishita, Moose 1990, and Koslov
Petitioner asserts that claims 1–3 would have been obvious over a
combination of Tsujishita, Moose 1990, and Koslov. Pet. 45. For this
ground, Petitioner asserts that Koslov5 discloses claim 1’s correcting step–
i.e., “correcting each decoded phase shift based on said averaged offset.” Id.
at 50–51. We disagree.

5 Petitioner also directs us to the same teachings of Tsujishita that are
discussed above in reference to the previous ground. See Pet. 49–51.
Petitioner’s arguments in this ground as to the combination of Tsujishita,
Moose 1990, and Koslov do not address any of the deficiencies of Tsujishita
that we addressed in reference to the prior ground.
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Petitioner cites, without explanation, Koslov at column 2, lines 22–57,
to support its allegation that “Figures 2–5 (and the associated text) describe
correcting each decoded phase shift based on said averaged offset.” Id.
Koslov’s Figures 2, 3, and 56 illustrate a circuit in which the output of phase
accumulator 112 generates an “integrated phase error” that ROM 114 uses to
select outputs of a trigonometric table to apply to the input of de-rotator 102.
Ex. 1009, 2:40–49. We note that Figures 2, 3, and 5 show the output of de-
rotator 102 as “DE-ROTATED SYMBOLS” output “TO DECODER.” As
such, Petitioner has not explained adequately how Koslov’s error correction
at de-rotator 102 is applied to “each decoded phase shift” as required by
claim 1. Therefore, we agree with Patent Owner that, as to the critical
correcting step, “Koslov is cumulative of Tsujishita.” Prelim. Resp. 53.
Thus, on this record, Petitioner has not shown a reasonable likelihood that it
would prevail in establishing claims 1–3 would have been obvious over
Tsujishita, Moose 1990, and Koslov.
XIV. CONCLUSION
For the foregoing reasons, we find, on the current record, that
Petitioner has not set forth a reasonable likelihood of succeeding on either of
the two asserted grounds of unpatentability, and we decline to institute an
inter partes review.

6 Koslov’s Figure 4 focuses on the details of frequency error detection
circuit 302 and does not advance our analysis as to whether the signal being
corrected has already been decoded. See Ex. 1009, Fig. 4, 5:39–41.
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I. ORDER
Accordingly, it is:
ORDERED that the Petition is denied as to the challenged claims of
the ʼ084 patent; and
FURTHER ORDERED that no inter partes review is instituted.

PETITIONER:
Jonathan S. Caplan
Jeffrey H. Price
Shannon H. Hedvat
KRAMER LEVIN NAFTALIS & FRANKEL LLP
jcaplan@kramerlevin.com
jprice@kramerlevin.com
shedvat@kramerlevin.com

PATENT OWNER:
Ben J. Yorks
Babak Redjaian
David McPhie
IRELL & MANELLA LLP
byorks@irell.com
bredjaian@irell.com
dmcphie@irell.com