Sierra Wireless, Ulc, Honeywell International Inc., Telit Cinterion Deutschland Gmbh… v. SISVEL S.P.A., Cross-Appellant 2023-1059, 2023-1085, 2023-1089, 2023-1125 Appeals…

United States Court of Appeals
for the Federal Circuit
______________________
SIERRA WIRELESS, ULC, HONEYWELL
INTERNATIONAL INC., TELIT CINTERION
DEUTSCHLAND GMBH F/D/B/A THALES DIS AIS
DEUTSCHLAND GMBH,
Appellants
v.
SISVEL S.P.A.,
Cross-Appellant
______________________
2023-1059, 2023-1085, 2023-1089, 2023-1125
______________________
Appeals from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2021-
00580.
______________________
Decided: March 10, 2025
______________________
K OURTNEY M UELLER M ERRILL, Perkins Coie LLP, Den-
ver, CO, argued for all appellants. Appellant Sierra Wire-
less, ULC also represented by AMANDA TESSAR ; TARA
LAUREN K URTIS, Chicago, IL.
ROBERT J. GAJARSA, Devlin Law Firm LLC, Wilming-
ton, DE, argued for cross-appellant. Also represented by
N EIL A. BENCHELL , TIMOTHY DEVLIN, N ADIIA LOIZIDES.
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 2
JEFFREY R. GARGANO, K&L Gates LLP, for appellant
Honeywell International Inc. Also represented by BRIAN
PAUL BOZZO, Pittsburgh, PA; ERIK H ALVERSON, San Fran-
cisco, CA.
G UY YONAY , Pearl Cohen Zedek Latzer Baratz LLP,
New York, NY, for appellant Telit Cinterion Deutschland
GmbH. Also represented by K YLE AUTERI , I.
______________________
Before M OORE, Chief Judge, S CHALL and TARANTO, Circuit
Judges.
M OORE , Chief Judge.
Sierra Wireless, ULC; Honeywell International Inc.;
and Telit Cinterion Deutschland GmbH (collectively, Ap-
pellants) appeal a final written decision of the Patent Trial
and Appeal Board (Board) holding claims 3–5, 9, and 10 of
U.S. Patent No. 7,869,396 were not shown to be unpatent-
able. Sisvel S.p.A. (Sisvel) cross-appeals the Board’s hold-
ing that claims 1, 2, and 6–8 of the ’396 patent are
unpatentable. For the following reasons, we vacate and re-
mand.
BACKGROUND
Sisvel owns the ’396 patent, which relates to “a data
transmission method and a data retransmission method
which can reduce loss in data transmission” in a wireless
communication system. ’396 patent at 1:17–20. Data is
packaged into protocol data units (PDUs) for transmission.
Id. at 6:48–52. PDUs are typically assigned sequence num-
bers to help the receiver detect missing PDUs and place
received PDUs in sequential order. Id. at 5:4–6; J.A. 1128–
29 ¶ 70. Prior art techniques for reducing data loss include
the automatic repeat request (ARQ) method, in which a re-
ceiver sends a message to a transmitter if an expected PDU
is not received, allowing the transmitter to retransmit the
missing PDU. ’396 patent at 1:58–2:5.
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 3
The ’396 patent claims a variation of the ARQ method
that aims to increase reliability and efficiency. Id. at 2:11–
13. In the claimed method, the receiver activates a timer
when a PDU is detected as missing. Id. at 14:28–30. If the
missing PDU is not received before the timer expires, a re-
ception failure is detected and reported to the transmitter.
Id. at 14:30–34. If the missing PDU is received before the
timer expires, the timer is stopped. Id. at 14:38–46.
Claims 1 and 8 are the only independent claims. Claim 1
reads:
1. [pre] A method of performing automatic repeat
request (ARQ) in a wireless communication sys-
tem, the method performed by a receiver and com-
prising:
[a] detecting whether at least one data block to be
received from a transmitter is missed;
[b] starting a timer when the at least one data block
is detected as missed;
[c] stopping the timer when the at least one data
block is received from the transmitter while the
timer is running, in order to prevent a triggering of
a status report before the timer expires; and
[d] transmitting the status report to the transmit-
ter after the timer expires, wherein the status re-
port comprises a positive acknowledgement
indicating receipt of at least one received data
block.
Id. at 16:39–53 (emphasis and bracketed labels added).
As relevant here, Appellants petitioned for inter partes
review of the ’396 patent, challenging all ten claims as an-
ticipated by and obvious in view of International Patent
Application Publication No. WO 02/091659 (Sachs). The
Board, in a divided opinion, held claims 1, 2, and 6–8 to be
unpatentable as anticipated by and obvious in view of
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 4
Sachs. The Board held claims 3–5, 9, and 10 were not
shown to be unpatentable. Appellants appeal the Board’s
holding as to claims 3–5, 9, and 10 and argue the Board
abused its discretion by relying on testimony from Sisvel’s
declarant, Regis Bates. Sisvel cross-appeals the Board’s
holding as to claims 1, 2, and 6–8. We have jurisdiction
under 28 U.S.C. § 1295(a)(4)(A).
D ISCUSSION
We review the Board’s legal conclusions de novo and its
factual findings for substantial evidence. Redline Detec-
tion, LLC v. Star Envirotech, Inc., 811 F.3d 435, 449 (Fed.
Cir. 2015). Anticipation is a question of fact. Blue Calypso,
LLC v. Groupon, Inc., 815 F.3d 1331, 1341 (Fed. Cir. 2016).
Obviousness is a question of law based on underlying find-
ings of fact. In re Gartside, 203 F.3d 1305, 1316 (Fed. Cir.
2000). What a prior art reference discloses is a question of
fact. Adasa Inc. v. Avery Dennison Corp., 55 F.4th 900, 910
(Fed. Cir. 2022). The level of ordinary skill in the art is a
question of fact. Arctic Cat Inc. v. Bombardier Recreational
Prods. Inc., 876 F.3d 1350, 1358 (Fed. Cir. 2017).
I. Sisvel’s Cross-Appeal: Claims 1, 2, and 6–8
Sisvel argues the Board erred in holding claims 1, 2,
and 6–8 to be unpatentable as anticipated and obvious
based on Sachs. Sisvel Br. 65–75. First, Sisvel argues the
Board erroneously construed limitations 1[c] and 1[d] as
conditional. Second, Sisvel argues the Board’s finding that
Sachs discloses limitation 1[c] is not supported by substan-
tial evidence. We agree with Sisvel on both counts.
The Board held limitations 1[c] and 1[d] are mutually
exclusive. That is, they “cannot both occur in response to
the same set of stimuli” because the timer either stops upon
receipt of the missing PDU (as required by limitation 1[c])
or expires without having received the missing PDU (as re-
quired by limitation 1[d]), but it cannot do both. J.A. 16–
17. On that basis, the Board held the prior art need only
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 5
disclose limitations 1[a], 1[b], and 1[c] or limitations 1[a],
1[b], and 1[d] to anticipate claim 1. Id. That conclusion
does not follow from the premise describing the claim lan-
guage. While the canons of claim construction teach that
claims should be construed to preserve their presumed va-
lidity, this is “[i]f, after applying all other available tools of
claim construction, a claim is ambiguous.” Ruckus Wire-
less, Inc. v. Innovative Wireless Sols., LLC, 824 F.3d 999,
1004 (Fed. Cir. 2016). Here, we reject the Board’s conclu-
sion because the plain and unambiguous language of claim
1 requires that a method, to come within the claim, must
perform both limitations 1[c] and 1[d] where their precon-
ditions apply. ’396 patent at 16:46–53 (“stopping the
timer . . . and transmitting the status report after the
timer expires” (emphasis added)).
The Board found Sachs Figure 5 discloses “stopping the
timer when the at least one data block is received from the
transmitter while the timer is running, in order to prevent
a triggering of a status report before the timer expires”
(limitation 1[c]):
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 6
J.A. 1295; J.A. 13–19. The Board relied on Sachs’ teaching
that “[i]n a preferred embodiment the timer is stopped be-
fore the timer expiry when at the reception of a data packet
the sequence is established.” J.A. 17–18 (quoting J.A.
1275–76 at 9:34–10:1). The Board found Sachs discloses
limitation 1[c] because the timer in Figure 5 is stopped
upon receipt of any missing PDUs, and not after the occur-
rence of some separate reordering procedure. J.A. 17–18.
The Board’s finding that Sachs Figure 5 discloses limi-
tation 1[c] is not supported by substantial evidence. Sachs
itself explains that Figure 5 depicts stopping the T_reorder
timer after PDUs have been put into sequential order. In-
deed, the portion of Sachs on which the Board relied ex-
plains “the timer is stopped before the timer expiry when
at the reception of a data packet the sequence is estab-
lished.” J.A. 17 (quoting J.A. 1275–76 at 9:34–10:1) (em-
phasis modified). In its description of the invention, Sachs
states “the reo[r]dering-delay shall preferably be stopped
when all outstanding PDUs are received and the sent se-
quence is re-established. This can be achieved by stopping
the duration of the T_reorder timer, when reordering is fin-
ished. This embodiment is shown in figure 5.” J.A. 1280
at 14:2–6 (emphasis added). Figure 5 itself is clearly la-
beled “stop timer when re-ordering is finished.” J.A. 1295.
Appellants’ own declarant, Dr. Apostolos Kakaes,
opined that according to Sachs Figure 5, the timer stops
after reordering and not upon receipt of the missing PDUs:
The timer continues until the [Radio Link Control
(RLC)] receiver receives each of the expected but
missing PDUs: 1, 2, 3, and 4 (which includes spe-
cifically PDU4) and thus has a complete, correctly
ordered subset, i.e., 1, 2, 3, 4, 5, 6, 7, and 8. When
that occurs, Figure 5 explains to ‘stop timer when
re-ordering is finished.’ Here, Sachs refers to the
reordering of the received PDUs in sequential or-
der in the buffer.
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 7
J.A. 1172–73 ¶ 154; see J.A. 233. Sisvel argued that Sachs
does not disclose limitation 1[c] because “Figure 5 discloses
stopping a timer, but only when reordering is finished.”
J.A. 515. Oddly, Appellants replied by citing this same par-
agraph of Dr. Kakaes’ declaration that states the T_reorder
timer stops when reordering is finished. J.A. 622 (citing
J.A. 1172–73 ¶ 154). The Sachs reference and evidence
from both parties indicate that the T_reorder timer of
Sachs Figure 5 is stopped when reordering is finished, ra-
ther than when missing PDUs are received. Therefore, the
Board’s fact finding to the contrary is not supported by sub-
stantial evidence.
Because the Board’s fact finding that Figure 5 discloses
limitation 1[c] is not supported by substantial evidence, we
vacate the Board’s holdings that claim 1 is anticipated by
and obvious in view of Sachs and its holdings regarding
claims 2 and 6–8, which incorporate this same erroneous
finding. See J.A. 20–22, 32–34.
II. Appellants’ Appeal: Claims 3–5, 9, and 10
Appellants appeal the Board’s determination that de-
pendent claims 3–5, 9, and 10 were not shown to be un-
patentable. Because we vacate the Board’s findings of
unpatentability of the independent claims, we need not
reach the Appellants’ arguments regarding dependent
claims 3–5, 9 and 10. We do, however, agree with Appel-
lants that the Board abused its discretion by relying on the
testimony of Sisvel’s expert Mr. Bates, absent a finding
that he is qualified as an ordinarily skilled artisan.
“To offer expert testimony from the perspective of a
skilled artisan in a patent case—like for claim construc-
tion, validity, or infringement—a witness must at least
have ordinary skill in the art.” Kyocera Senco Indus. Tools
Inc. v. Int’l Trade Comm’n, 22 F.4th 1369, 1376–77 (Fed.
Cir. 2022). We review the Board’s evidentiary determina-
tions, including the credibility of expert testimony, for
abuse of discretion. See Shoes by Firebug LLC v. Stride
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 8
Rite Children’s Grp., LLC, 962 F.3d 1362, 1372 (Fed. Cir.
2020). “The Board abuses its discretion if its decision (1) is
clearly unreasonable, arbitrary, or fanciful; (2) is based on
an erroneous conclusion of law; (3) rests on clearly errone-
ous fact finding; or (4) involves a record that contains no
evidence on which the Board could rationally base its deci-
sion.” ClearOne, Inc. v. Shure Acquisition Holdings, Inc.,
35 F.4th 1345, 1351 (Fed. Cir. 2022) (internal quotation
marks and citation omitted).
Appellants argue the Board abused its discretion by
crediting Sisvel’s declarant, Mr. Bates, because he was not
a skilled artisan under the Board’s definition. Appellants
Br. 62–64. The Board found a skilled artisan to the ’396
patent “would have had a degree in electrical engineering
or a similar discipline, with at least three years of relevant
industry or research experience, including experience de-
signing or implementing wireless radio systems for data
transmission and retransmission.” J.A. 8. Mr. Bates lacks
a technical degree in electrical engineering or any other en-
gineering or science discipline. J.A. 3138 ¶ 7. His profes-
sional experience relates to “designing, building,
optimizing and training others in many aspects of telecom-
munications systems,” J.A. 3138 ¶ 8, but does not specifi-
cally include “designing the channels and methods for
transmitting and retransmitting data in a cellular net-
work,” J.A. 3091 at 45:18–46:16. Mr. Bates’ experience
does not, on its face, satisfy the Board’s requirements for a
skilled artisan. Mr. Bates’ declarations opine on anticipa-
tion and obviousness, issues that must be examined from
the perspective of a skilled artisan. J.A. 3157–62 (declara-
tion of Mr. Bates); J.A. 3209–15 (second declaration of Mr.
Bates); Wasica Fin. GmbH v. Cont’l Auto. Sys., Inc., 853
F.3d 1272, 1284 (Fed. Cir. 2017) (“Anticipation is an in-
quiry viewed from the perspective of one skilled in the
art.”); HVLPO2, LLC v. Oxygen Frog, LLC, 949 F.3d 685,
688 (Fed. Cir. 2020) (“Obviousness and each of its underly-
ing components are analyzed from the perspective of a
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SIERRA WIRELESS, ULC v. SISVEL S.P.A . 9
person of skill in the art.”). The Board cited and relied upon
Mr. Bates’ testimony throughout its anticipation and obvi-
ousness analyses. See, e.g., J.A. 24, 26, 28, 30. Appellants
contend the Board’s failure to provide reasoning for its de-
cision to credit Mr. Bates’ testimony was an abuse of dis-
cretion. We agree.
Sisvel argues Mr. Bates has decades of experience in
the telecommunications field, which more than suffices to
satisfy the engineering degree required by the Board’s or-
dinarily skilled artisan finding. Sisvel Br. 62–64. The
Board, however, made no such determination regarding
whether Mr. Bates qualifies as a skilled artisan despite his
lack of credentials specified in the Board’s definition.
Whether Mr. Bates’ experience suffices to meet the require-
ments for a person of skill in the art is a question of fact
that we will not decide in the first instance, and we thus
vacate for Board consideration of this issue.
CONCLUSION
For the foregoing reasons, we vacate the Board’s hold-
ing that claims 1, 2, and 6–8 are unpatentable as antici-
pated by and obvious in view of Sachs. We hold that the
Board abused its discretion by relying on Mr. Bates’ testi-
mony where he does not satisfy the requirements for an or-
dinarily skilled artisan and the Board made no finding that
his years of experience were sufficient to establish that he
was at least an ordinarily skilled artisan. Because we va-
cate on Sisvel’s cross-appeal, which includes the independ-
ent claims, we need not reach Appellants’ appeal regarding
the patentability of dependent claims 3–5, 9, and 10. We
remand for further proceedings consistent with this opin-
ion.
VACATED AND REMANDED
COSTS
No costs.
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