Ex Parte Litwin

Board of Patent Appeals and Interferences

Aug 3, 2011

10567717 (B.P.A.I. Aug. 3, 2011)

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.
10/567,717 02/08/2006 Louis Robert Litwin PU030177 4024
24498 7590 08/03/2011
Robert D. Shedd, Patent Operations
THOMSON Licensing LLC
P.O. Box 5312
Princeton, NJ 08543-5312
EXAMINER
NGUYEN, QUANG N
ART UNIT PAPER NUMBER
2441
MAIL DATE DELIVERY MODE
08/03/2011 PAPER
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.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte LOUIS ROBERT LITWIN
____________

Appeal 2009-011704
Application 10/567,717
Technology Center 2400
____________

Before HOWARD B. BLANKENSHIP, JOHN A. JEFFERY, and
THU A. DANG, Administrative Patent Judges.

JEFFERY, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2009-011704
Application 10/567,717

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Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1-12 and 14-21. We have jurisdiction under 35 U.S.C.
§ 6(b). We affirm.

STATEMENT OF THE CASE
Appellant’s invention detects the presence of a Wireless Local Area
Network (WLAN) by identifying energy fluctuations in a signal without
needing to activate a WLAN baseband circuit or recover a carrier. See
generally Spec. 1-2, 8-10; Figs. 2-4, 8. Claim 1 is illustrative with key
disputed limitations emphasized:
1. A method, comprising:
scanning, by a wireless local area network scanner in a
wireless device, to detect the presence of a wireless local area
network WLAN;
detecting the presence of said wireless local area network
by employing said wireless local area network scanner to
identify energy fluctuations without a wireless local area
network baseband circuit being activated to process data;
contacting a base station of said wireless local area
network by the wireless local area network baseband circuit in
said wireless device in response to detection of said wireless
local area network to request location of said base station; and
receiving location of said wireless local area network.

The Examiner relies on the following as evidence of unpatentability:
Sundar US 2003/0134650 A1 July 17, 2003
Hsu US 2004/0205158 A1 Oct. 14, 2004
(filed Feb. 24, 2003)
Rao US 2004/0264395 A1 Dec. 30, 2004
(filed June 25, 2003)
Bahl US 7,110,783 B2 Sept. 19, 2006
(filed Apr. 17, 2002)
Appeal 2009-011704
Application 10/567,717

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Brandon Ogilvie, Clock Solutions for WiFi (IEEE 802.11), Pericom
Semiconductor, 1-4, (2003), available at
http://www.pericom.com/pdf/applications/AN070.pdf (“Ogilvie”).

Applicant’s Admitted Prior Art (Spec. 10:15-18) (“APA”).

THE REJECTIONS
1. The Examiner rejected claims 1-4, 6, 7, 9-12, and 15-21 under 35
U.S.C. § 103(a)1 as unpatentable over Hsu and APA. Ans. 4-7.2
2. The Examiner rejected claim 5 under 35 U.S.C. § 103(a) as
unpatentable over Hsu, APA, and Rao. Ans. 7-8.
3. The Examiner rejected claims 8 and 14 under 35 U.S.C. § 103(a) as
unpatentable over Hsu, APA, and Sundar. Ans. 8-9.

THE OBVIOUSNESS REJECTION OVER HSU AND APA
Regarding representative claim 1, the Examiner finds that Hsu detects
presence of a WLAN, but does not explicitly teach doing so by identifying
energy fluctuations without activating a WLAN baseband circuit as claimed.
Ans. 4-6, 10-13. The Examiner, however, finds that this feature would have
been obvious in view of Appellant’s admission in the Specification
regarding the frequency-reference accuracy specified in the IEEE 802.11b
standard which is said to enable detection without the baseband circuit’s
automatic frequency control capabilities. Id.

1 Although the Examiner erroneously indicates that this rejection is based on
§ 102, we nonetheless provide the correct statutory basis here (§ 103).
Accord Br. 7; Ans. 3 (confirming the status of this rejection under § 103).
2 Throughout this opinion, we refer to the Appeal Brief filed November 24,
2008 and the Examiner’s Answer mailed December 19, 2008 (supplemented
June 4, 2009).
Appeal 2009-011704
Application 10/567,717

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Appellant argues that the Examiner mischaracterized Appellant’s
discussion in the Specification as admitted prior art since Appellant merely
indicated that that the frequency-reference accuracy specified in the standard
was known in the art—not detecting WLAN presence by identifying energy
fluctuations without activating a WLAN baseband circuit (claim 1) or
performing carrier recovery (claim 9) which are significant features of the
claimed invention recognized only by Appellant. Br. 9-12, 19-20.

ISSUES
Under § 103, has the Examiner erred by finding that Hsu and APA
collectively would have taught or suggested detecting WLAN presence via
scanning to identify energy fluctuations without (1) activating a WLAN
baseband circuit to process data as recited in claim 1, and (2) performing
carrier recovery as recited in claim 9?

FINDINGS OF FACT (FF)
1. According to Appellant:
Abrupt periodic changes in noise-like energy (e.g., energy
fluctuations in the [Radio Frequency (RF)] signal) will indicate
activity resulting from medium access control (MAC) layer
processes in WLANs. In one embodiment, the WLAN energy
detector 338 scans for energy fluctuations that correspond to
periodic beacons transmitted in the RF signal. For example, in
IEEE 802.11 standards, beacons are periodically transmitted at
a programmable rate (e.g., typically 10 Hz). Detecting the
presence of these 10 Hz energy fluctuations in the RF signal
can provide an indication of the presence of a WLAN.

Spec. 8:15-23.
2. According to Appellant:
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To detect the energy pulses 806, the present invention
employs the energy change detector 516. As described below
with respect to Figure 6, the energy change detector 516 detects
the energy pulses 806 and generates a WLAN present signal to
send to the controller 330. Since the present invention is only
scanning for the presence of energy fluctuations in an RF
signal, and is not recovering data from the RF signal, the
present invention advantageously obviates the need to
synchronize the RF signal and perform carrier recovery. The
frequency reference accuracy specified in WLAN standards
(e.g., ±25 ppm as specified in the IEEE 802.11b standard) can
allow the [phase-locked loop (PLL)] circuit 314 to operate
without automatic frequency control (AFC) provided by the
WLAN baseband circuitry. As such, the WLAN baseband
circuitry 208 does not have to be activated to detect the
presence of the WLAN, thereby conserving power and saving
battery life in the mobile device.

Spec. 10:8-20.
3. In one embodiment, Hsu’s Mobile Station (MS) 300 has two tuners
(“A” and “B”) that can simultaneously tune to WLAN and cellular
frequencies, respectively. When the MS is within range of accessing Access
Point (AP) 320, tuner A 304 scans for a WLAN beacon that the AP transmits
periodically and identifies the WLAN. Hsu, ¶ 0078, Fig. 6.
4. One WLAN protocol defined by IEEE 802.11 allows the MS to
scan the WLAN passively or actively. In passive scanning, the MS listens
for the WLAN beacon sent by the AP on WLAN frequencies, where the
beacon contains the AP’s ESSID. If the AP’s ESSID matches that stored in
the MS’s ESID list, the WLAN is detected. In active scanning, the MS
sends a Probe Request containing the MS’s ESSID to the AP which returns a
Probe Response if the received ESSID matches that of the AP. Hsu, ¶ 0083;
Fig. 6.
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Application 10/567,717

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5. Ogilvie includes the text “09/05/03” in the bottom shaded margin
on all pages. Ogilvie, at 1-4.
6. The present application was filed February 8, 2006 under 35
U.S.C. § 371 in connection with PCT/US03/26419 filed August 22, 2003.
7. Since messages in Bahl are passed between low-power transceivers
100, 102 and host transceiver 212 over a low-power control channel distinct
from the primary communication channel (e.g., an 802.11 channel), the
wireless computing devices’ standard high-power cards need not be used.
Bahl, col. 9, ll. 4-12; Fig. 4.

ANALYSIS
Claims 1-4, 6, 7, and 16-21
We begin by noting that the key disputed limitations in this appeal are
negative limitations, namely detecting WLAN presence by identifying
energy fluctuations without (1) activating a WLAN baseband circuit to
process data (claim 1), or (2) performing carrier recovery (claim 9).
Although permissible,3 negative limitations merely recite what a claim lacks
and are thus broad by their very nature. Therefore, to show error in the
Examiner’s findings of what claims lack via negative limitations, Appellant
must show that the cited prior art has those features. That has simply not
been done here.
The Examiner acknowledges that Hsu does not explicitly teach
detecting WLAN presence by identifying energy fluctuations without

3 See generally Animal Legal Defense Fund v. Quigg, 932 F.2d 920, 923
(Fed. Cir. 1991) (“The use of a negative limitation to define the metes and
bounds of the claimed subject matter is a permissible form of expression.”)
(citation omitted).
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activating a WLAN baseband circuit as claimed, but cites APA to evidence
this teaching. Ans. 4-6, 10-13. We emphasize (as does the Examiner) the
term “explicitly” here, for the record before us strongly suggests that Hsu at
least implicitly teaches this feature.
First, a key aspect of Hsu’s WLAN detection function is scanning for
a WLAN beacon that is transmitted periodically (FF 3)—a non-continuous
transmission that, when received, identifies the associated energy
fluctuations with each transmission. That is, the respective signals
associated with each beacon transmission have greater signal strength
relative to the periods between transmissions, and therefore constitute
periodic energy fluctuations that are identified when received. That Hsu
graphically depicts these periodic transmissions with multiple, spaced
upward arrows in Figure 6 only bolsters this conclusion.
Second, Appellant notes in the Specification that under IEEE 802.11
standards, beacons are periodically transmitted at a programmable rate,
typically 10 Hz. FF 1. Notably, this very protocol is used in Hsu. FF 4. To
be sure, Hsu’s scanning techniques involve comparing particular identifiers
contained in either the beacon signal or other signals as Appellant argues
(Br. 11; FF 4), and therefore would involve data processing. But that does
not mean that the data processed via the identified energy fluctuations (i.e.,
the received periodic beacon signal) would necessarily be done by activating
a WLAN baseband circuit4 which would run counter to the recited negative

4 The term “baseband” is defined as “[t]he frequency band occupied by all
the transmitted signals that modulate a particular carrier. . . . [An] example is
the band containing all the modulated subcarriers in a carrier system.” Neil
Sclater & John Markus, MCGRAW-HILL ELECTRONICS DICTIONARY 37 (6th
ed. 1997).
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limitation. Appellant has identified no such circuit in Hsu, nor will we
speculate in this regard here in the first instance on appeal. Simply put, not
only has Appellant not shown that Hsu’s WLAN detection involves or is
otherwise limited to a WLAN baseband circuit, but Appellant has likewise
failed to show that omitting such a circuit (even if it were used in Hsu) or
replacing such a baseband circuit with equivalent functionality for signal
processing would not have been obvious.
Therefore, even assuming that Appellant’s admission in the passage
relied upon by the Examiner is limited to frequency-reference accuracy
specified in the IEEE 802.11b standard as Appellant contends (Br. 11-12; FF
2), we still fail to see why it would not have been obvious to detect WLAN
presence by identifying energy fluctuations without activating a WLAN
baseband circuit to process data in Hsu for the reasons noted above.5

5 Although the Examiner cites an additional reference to Bahl (Ans. 11-12),
this reference is only marginally relevant here regarding the core issue in
dispute, namely whether the prior art identifies energy fluctuations without
activating a WLAN baseband circuit to process data as claimed. Although
Bahl indicates that a low-power control channel can be used to pass
messages in lieu of a higher-power communications channel (FF 7), it is
unclear whether a WLAN baseband circuit would or would not be used to
this end. And to the extent that the Examiner relies on Ogilvie as additional
support in this regard (Supp. Ans. (Evidence Relied Upon section)), this
reference does not qualify as prior art since it published after the effective
filing date of the present application as Appellant indicates. Br. 12-13
(citing Exh. A in Ev. App’x). Compare FF 5 with FF 6.
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Application 10/567,717

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We are therefore not persuaded that the Examiner erred in rejecting
representative claim 1, and claims 2-4, 6, 7, and 16-21 not separately argued
with particularity.6

Claims 9-12 and 15
We likewise sustain the Examiner’s rejection of claim 9 which recites,
in pertinent part, detecting WLAN presence via scanning to identify energy
fluctuations without performing carrier recovery. As with the negative
limitation of claim 1, Appellant has not shown that Hsu’s WLAN detection
involves carrier recovery to run counter to the negative limitation.
Apart from merely asserting that carrier recovery is performed to
extract data from a WLAN signal (Br. 20), Appellant provides no evidence
on this record to support this assertion, at least regarding Hsu’s system. Nor
will we speculate in this regard here in the first instance on appeal. And
even assuming, without deciding, that Hsu recovers a carrier to process
received signals or data (a finding that has not been made on this record in
any event), Appellant has not shown that replacing this technique with
equivalent functionality (or omitting it altogether) for signal processing
would not have been obvious.
We are therefore not persuaded that the Examiner erred in rejecting
representative claim 9, and claims 10-12 and 15 not separately argued with
particularity.

6 Although Appellant nominally argues claims 16-21 separately (Br. 23-24),
the arguments are similar to those for claim 1. Our analysis regarding claim
1 therefore applies to these claims as well.
Appeal 2009-011704
Application 10/567,717

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THE OTHER OBVIOUSNESS REJECTIONS
We will also sustain the Examiner’s obviousness rejections of claims
5, 8, and 14. Ans. 7-9. Appellant has not particularly pointed out errors in
the Examiner’s reasoning to overcome the Examiner’s obviousness
conclusions, but merely reiterates similar arguments made in connection
with claims 1 and 9, and that the additional cited references do not cure
those deficiencies. Br. 17-18, 20-23. We are not persuaded by these
arguments, however, for the reasons previously discussed. The rejections
are therefore sustained.

CONCLUSION
The Examiner did not err in rejecting claims 1-12 and 14-21 under
§ 103.

ORDER
The Examiner’s decision rejecting claims 1-12 and 14-21 is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

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