Ex Parte Xu et al

Patent Trial and Appeal Board

Feb 28, 2017

13761568 (P.T.A.B. Feb. 28, 2017)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/761,568 02/07/2013 Guijin Xu 81343090US14 1606
97291 7590 03/02/2017
Huawei Technologies Co., Ltd.
c/o Wenjun Gu (Huawei ID 00229515)
Building Gl-2, Huawei Industrial Base,
Bantian, Longgang District,
Shenzhen, 518129
CHINA
EXAMINER
LUGO, DAVID B
ART UNIT PAPER NUMBER
2631
NOTIFICATION DATE DELIVERY MODE
03/02/2017 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
uspatent@huawei.com
shiming. wu @huawei.com
ltian @ huawei. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte GUIJIN XU, GUOZHU LONG, RUIJIE XIAO, ZHILEI ZHAO,
XUYONG WU, and YUCHEN JIA
Appeal 2015-007048
Application 13/761,568
Technology Center 2600
Before MARC S. HOFF, THU A. DANG, and JOHN D. HAMANN,
Administrative Patent Judges.
DANG, Administrative Patent Judge.
DECISION ON APPEAL
I. STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) of the Examiner’s Final
Rejection of claims 1, 2, 13—17, 23, 24, 27—29, and 31. Claims 3—7, 21, 22,
25, 26, and 30 were canceled. The Examiner indicates that claims
8—12, and 18—20 contain allowable subject matter. Final. Act. 6. We have
jurisdiction under 35 U.S.C. § 6(b).
We reverse.
Appeal 2015-007048
Application 13/761,568
A. THE INVENTION
According to Appellants, the invention “relates to the communication
field, and more particularly, to a method, an apparatus, and a system for time
synchronization of a Digital Subscriber Line (DSL)” (Spec. 12).
B. ILLUSTRATIVE CLAIM
Claim 1 is exemplary:
1. A method for time synchronization of a digital subscriber line (DSL),
the method comprising:
receiving, by a first apparatus, a second symbol transmitted by a
second apparatus, and obtaining a time Tsl at which the second symbol
is received by the first apparatus;
transmitting, by the first apparatus, a first symbol to the second
apparatus, and obtaining a time Ts2 at which the first symbol is
transmitted by the first apparatus;
obtaining, by the first apparatus, a time Tm2 at which the first
symbol is received by the second apparatus;
calculating, by the first apparatus, an offset between a clock of
the apparatus and a clock of the second apparatus according to the time
Tsl, the Ts2, the time Tml and the time Tm2; and
adjusting, by the first apparatus, the clock of the first apparatus
with the offset to synchronize with the clock of the second apparatus
apparatus;
wherein the time Ts2 is a time at which a sample at a starting
position of the first symbol is transmitted by the first apparatus, the time
Tm2 is a time at which the same sample at the starting position of the
second symbol is transmitted by the second apparatus, and the time Tsl
is a time at which the same sample at the starting position of the second
DMT symbol is received by the first apparatus,
wherein the offset is computed based on an assumption that a
downstream propagation delay and an upstream propagation delay of a
twisted pair of the DSL are approximately identical.
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Appeal 2015-007048
Application 13/761,568
C. REJECTIONS
Claims 1, 2, 15, 17, and 27—29 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Eidson (US 7,602,873 B2; iss. Oct. 13,
2009), Rangan et al. (US 2009/0170430 Al; pub. July 2, 2009), and
Brueckheimer (US 2009/0147806 Al; pub. June 11, 2009).
Claims 13, 14, 16, 23, 24, and 31 stand rejected under 35 U.S.C.
103(a) as being unpatentable over Eidson, Rangan, Brueckheimer, and
further in view of Jones et al. (US 6,697,768 B2; iss. Feb. 24, 2004).
II. ISSUE
The issue before us is whether the Examiner erred in finding that
Eidson (in view of Rangan and Brueckheimer) teaches or suggests “offset
. . . computed based on an assumption that a downstream propagation delay
and an upstream delay of a twisted pair of the DSL are approximately
identicaF (claim 1, emphasis added).
III. ANALYSIS
According to Appellants, “Eidson generally discloses a method for
correcting time synchronization inaccuracy caused by asymmetric delay on a
communication link” (App. Br. 6). Thus, “the determination of the offset in
Eidson needs to incorporate the asymmetry between the propagation delay
on the first portion 112 (e.g., downstream propagation delay) and the
propagation delay on the second portion (e.g., upstream propagation delay)”
(id.). That is, “Eidson is not based on an assumption that the propagation
delay on the first portion 112 and the propagation delay on the second
portion 114 are approximately identical” (id.).
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Appeal 2015-007048
Application 13/761,568
After reviewing the record on appeal, we find the preponderance of
evidence supports Appellants’ position. Even though we agree with the
Examiner that “the claim recites the term ‘approximately identical’” (Ans. 5,
citing claim 1), and we find no error with the Examiner’s interpretation of
“approximately” as “almost, but not completely, accurate or exact; roughly”
{id., citation omitted), we do not find any teaching or suggestion in the
referenced portions of outputting “based on assumption” that the upstream
and downstream delay are “approximately identical,” as required by claim 1.
In particular, even though we agree with the Examiner that “[t]he difference
between the two propagation delays” represented by “differential delay 8a” is
“a small amount that may be determined according to the equation in
column 5, line 56 [of Eidson]” {id.), we do not find any disclosure or even a
suggestion of the computation of the offset (i.e., 0) being based on any
assumption that the “differential delay Sa” is “a small amount.” That is,
although it is possible that the “differential delay Sa” is in fact “a small
amount,” there is no disclosure or suggestion that the offset is based on any
assumption that the two propagation delays are “i.e., close to, almost, but not
completely or roughly identical,” as the Examiner finds {id.). Instead, we
agree with Appellants that, as set forth in the cited sections of Eidson, “the
determination of the offset in Eidson needs to incorporate the asymmetry
between [the two propagation delays]” (App. Br. 6).
Here, to affirm the Examiner’s finding of obviousness would require
us to resort to speculation, unfounded assumptions, or hindsight
reconstruction. See In re Warner, 379 F.2d 1011, 1017 (CCPA 1967). We
do not resort to hindsight reconstruction, speculation, or assumptions to cure
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Appeal 2015-007048
Application 13/761,568
the deficiencies in the proffered combination in order to support the
Examiner’s rejection.
Because we find at least one of the dispositive arguments advanced by
Appellants is supported by a preponderance of the evidence, we need not
reach the merits of Appellants’ other arguments.
Accordingly, we are constrained on this record to reverse the
Examiner’s 35 U.S.C. § 103 rejections of independent claim 1, independent
claims 17, 27, and 28 reciting similar limitations, and claims 2, 15, and 29
depending respectively from claims 1 and 28, over Eidson, in further view of
Rangan and Brueckheimer. The Examiner does not show how Jones
overcomes the deficiencies of Eidson, Rangan, and Brueckheimer.
Therefore, we, also reverse the Examiner’s 35 U.S.C. §103 rejections of 13,
14, 16, 23, 24, and 31 over Eidson, Rangan, and Brueckheimer, further in
view of Jones.
V. CONCLUSION AND DECISION
We reverse the Examiner’s rejections of claims 1, 2, 13—17, 23, 24,
27-29, and 31 under 35 U.S.C. § 103(a).
REVERSED
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