Ex Parte LI et al

Board of Patent Appeals and Interferences

Jan 29, 2010

10742011 (B.P.A.I. Jan. 29, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte QINGHUA LI and XINTIAN E. LIN
____________

Appeal 2009-005270
Application 10/742,011
Technology Center 2600
____________

Decided: January 29, 2010
____________

Before KENNETH W. HAIRSTON, KARL D. EASTHOM, and
BRADLEY W. BAUMEISTER, Administrative Patent Judges.

EASTHOM, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the final rejection of
claims 1-5, 7-14, 16-29, and 31-41.1 (Br. 2.) Subsequent to the appeal, the
Examiner objected to claims 5, 14, 23, 24, and 33 as dependent claims

1 This opinion refers to Appellants’ Brief (filed Sept. 4, 2008) [hereinafter
“Br.”], the Examiner’s Answer (mailed May 6, 2008) [hereinafter “Ans.”],
and the Final Office Action (mailed Oct. 16, 2007) [hereinafter “Fin. Rej.”].
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containing allowable subject matter. (Ans. 14.) Claims 6, 15, and 30 have
been cancelled. Therefore, claims 1-4, 7-13, 16-22, 25-29, 31, 32, and 34-41
are the subject of this appeal. No other claims are pending. We have
jurisdiction under 35 U.S.C. § 6(b).
We affirm-in-part.
Appellants disclose transmit power control techniques for use in
wireless networks implementing spatial division multiple access (SDMA)
antenna control. The various embodiments employ packet exchanges to
control the power of client devices. (Abstract, Fig. 1. ) Exemplary claim 1
follows:

1. A wireless access point (AP) for use in a wireless network,
comprising:
a wireless transceiver to support wireless communication with
wireless client devices in a vicinity of the wireless AP; and
a client transmit power control unit to manage transmit power control
activities for wireless client devices, said client transmit power control unit
to cause said wireless transceiver to transmit to a first client device, after it is
determined that the first client device should change a current transmit
power level, a first packet having a first transmit power level and a second
packet having a second transmit power level, wherein a difference in
decibels between the first transmit power level and the second transmit
power level is indicative of a desired transmit power level change in the first
client device.

The Examiner relies on the following prior art references:
Larsson US 2002/0172186 A1 Nov. 21, 2002
Adachi US 6,983,167 B2 Jan. 3, 2006
Katz US 7,072,692 B1 July 4, 2006

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Claims 1-4, 7-13, 16-22, 29, 31-32, and 34-38 stand rejected as
obvious under 35 U.S.C. § 103 based on Larsson and Adachi;2
Claims 39-41 stand rejected as obvious under 35 U.S.C. § 103(a)
based on Adachi and Larsson; and
Claims 25-28 stand rejected as obvious under 35 U.S.C. § 103(a)
based on Larsson, Adachi, and Katz.

ISSUES
Appellants (Br. 10-17) contest the Examiner’s finding that Adachi
teaches a client device responding to power based on a difference in power
transmitted in two successive packets from an access point (AP).
Appellants’ arguments focus on claim 1, hereby selected as representative of
the group. Appellants’ contentions raise the following pivotal issue: Did
Appellants show that the Examiner erred in finding that Larsson and Adachi
collectively teach “a first packet having a first transmit power level and a
second packet having a second transmit power level, wherein a difference in
decibels between the first transmit power level and the second transmit
power level is indicative of a desired transmit power level change in the first
client device,” as set forth in claim 1?

2 The Examiner did not list claims 34 and 35 in the rejection heading, but
did address them in the statement of rejection. (Ans. 8, 9.) Conversely, the
Examiner did list claims 27 and 28 in the rejection heading, but did not
address them in the statement of the rejection. As the Examiner rejected
these latter claims based on the additional reference to Katz, the rejections
are considered to be as listed here. (Accord Br. 8.) The Examiner withdrew
the rejection of claim 17 based on a failure to comply with the written
description requirement. (Compare Fin. Rej. 3-4 with Ans. 4.)
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Appellants (Br. 20-21, 25-27) also contest the Examiner’s finding that
Larsson and Adachi collectively teach receiving an IEEE 802.11h transmit
power control (TPC) packet from a wireless device at a wireless access
point, raising the following issue with respect to claims 34 and 39: Did
Appellants show that the Examiner erred in finding that Larsson and Adachi
collectively teach receiving an IEEE 802.11h transmit power control (TPC)
packet from a wireless device at a wireless access point?
With respect to claims 7, 16, 19, and 20, Appellants contest the
Examiner’s findings with respect to the manner of controlling power, e.g.,
whether or not the prior art suggests controlling power based on power
detection employing units of decibels (db) and other specific decibel
calculations. The specific contentions and issues related to these claims, and
others, are addressed more fully below.

FINDINGS OF FACT (FF)
Adachi
1. Adachi teaches controlling wireless station (STA) power by
sending a beacon packet S101 followed by an authentication packet S105
from an access point (AP) to the STA. (Fig. 7.) The STA determines the
transmitted power and measures the received power in each of the packets
and sets its power accordingly. (Fig. 9; col. 9, ll. 62 to col. 10, l. 63; col. 12,
l. 29 to col. 13, l. 2.)
Adachi describes received power and the transmitted power
information in terms of relative numbers (e.g. 1-4), or other codes. As to the
transmitted power, the power numbers (or codes) are embedded in the
respective transmitted beacon and authentication packet frames at the AP
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transmitting site. (Col. 8, ll. 44-67; col. 10, ll. 10-14, 44-45; col. 11, ll. 8-
49.)
The AP includes transmitters and receivers, and a transmission
controller 14. (Fig. 2.) To control power in the STAs, the controller 14
controls the sending of data in beacon and unicast packets to the STAs.
Based on the two packet types, the measured received power, and the
transmitted power level information carried in the packets, the STAs set the
power at a “predetermined level” (col. 12, l. 5). (Col. 5, ll. 21-24; col. 6, l.
53 to col. 7, l. 24; col. 12, ll. 1-5.)
The STAs can determine whether a packet frame is a beacon
(broadcast/omni) frame or a unicast frame from header information in the
frames/packets. A STA can assume that a unicast frame is a directional
frame. (Col. 6, l. 53 to col. 7, l. 24; col. 8, ll. 34-48; col. 9, ll. 1-9; col. 14, ll.
26-49.)
Adachi depicts a flow diagram of the power control process in Figure
8. Adachi notes that steps S202 and S203 in Figure 8 can be skipped. (Col.
11. ll. 63-67.) According to Figure 8, in step S201, the system determines
whether directional beam control occurs. In steps S202 and S203, a STA
determines the extent to which the antennas are focused (i.e. the extent to
which they are directional) by measuring received power and taking into
account transmitted power of the two packets. However, the extent to which
a beam carrying a unicast frame is directional can be assumed – i.e., pre-set
at a default level known at the STAs. (Col. 10, ll. 54-57.) In the last step,
step S204, the power in the STA is set based in part on the transmitted
power levels carried in the two known packet types (beacon and unicast).
(Col. 6, l. 53 to col. 7, l. 24; col. 8, ll. 30-67; col. 9, ll. 1-9; col. 14, ll. 26-49.)
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Adachi also describes measuring received power to determine, with
the known packet types and transmitted power, the extent to which the
antenna beams are directional (to determine beam gain and compare it to
thresholds). In other words, the STAs measure the received power in the
two packet types, determine the transmitted power level information from
the known packet types, determine if SDMA directional beam control
(SDMA) is occurring, and finally (in step S204) set the STA power
accordingly. (Col. 11, l. 8 to col. 12, l. 9.)
Adachi describes the process as follows:
By using received power information of an
omnidirectional beam and received power information of a
directional beam, the gain of a directional beam used by the
access point to transmit a unicast frame addressed to a station is
estimated. It is possible to precisely estimate the gain of the
directional beam by considering the transmitted power
information for the directional beam and the transmitted power
information for the non-directional beam. It is also possible to
estimate the gain of the directional beam by considering the
transmitted power information and the received power
information when a frame type (broadcast/unicast) is not used.

(Col. 7, ll. 8-19.)
2. Adachi teaches an SDMA (Space Division Multiple Access)
adaptive antenna array system and indicates that it is used to allow “plural
stations [to] perform simultaneous communication through the same
channel” (col. 2, ll. 1-3) in an efficient manner. (Col. 1, ll. 46-53.) The
directional antenna systems of SDMA also reduce interference between
STAs operating on the same channel. (Col. 1, ll. 46-62, col. 3, ll. 49-51.)
Larsson
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3. Larsson discloses sending information in frame packets in terms of
dB (decibel) steps. (¶ 0135.) Larsson’s wireless system mitigates
interference by controlling transmit power. (¶ 0033.)
Appellants’ Specification
4. Appellants’ Figure 3 represents a power control scheme. Figure 3
indicates that a remote device controls power in a client device by first
determining the receive power of the client device, and if that is within a
certain range, transmitting two packets (RTS and NULL) to cause a change
in the client device power.
5. Appellants describe another approach to control the client device
power:
[T]he client transmit power control unit 40 will cause the
wireless transceiver 34 to transmit a first packet to the client
device at a first transmit power level and a second packet to the
client device at a second transmit power level. After receiving
the first and second packets, the client device can then
determine how to change its transmit power level based on a
comparison between the receive power levels of the two
packets.
(Spec. 6:27 to 7:2.)
PRINCIPLES OF LAW
“[T]he examiner bears the initial burden, on review of the prior art or
on any other ground, of presenting a prima facie case of unpatentability.” In
re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992). Appellants carry the
burden on appeal to show reversible error by the Examiner in maintaining
the rejection. See In re Kahn, 441 F.3d 977, 985-86 (Fed. Cir. 2006) (“On
appeal to the Board, an applicant can overcome a rejection by showing
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insufficient evidence of prima facie obviousness or by rebutting the prima
facie case with evidence of secondary indicia of nonobviousness.” (Citation
omitted).)
Under § 103, “there must be some articulated reasoning with some
rational underpinning to support the legal conclusion of obviousness.” In re
Kahn, 441 F.3d at 988. Obviousness is determined on the basis of the
evidence as a whole and the relative persuasiveness of the arguments. See In
re Oetiker, 977 F.2d at 1445.
ANALYSIS
Rejection of Claims 1 and 25-28
With respect to claim 1, Appellants summarize their position and the
Examiner’s as follows:
It appears that the argument that the Examiner [sic] making is
that the station in Adachi uses the transmit power levels of the
beacon packet and the authentication frame to determine
whether to change the transmit power level of the station and,
therefore, it discloses the claimed subject matter. However, the
claim is directed to a wireless AP that includes “a client
transmit power control unit to manage transmit power control
activities for wireless client devices, said client transmit power
control unit to cause said wireless transceiver to transmit to a
first client device . . . a first packet having a first transmit power
level and a second packet having a second transmit power level,
wherein a difference in decibels between the first transmit
power level and the second transmit power level is indicative of
a desired transmit power level change in the first client device.”
Even though the station in Adachi may use the transmit power
levels of the beacon packet and the authentication frame to
determine whether to change its transmit power level, the
difference in decibels between the transmit power level of the
beacon packet and the transmit power level of the
authentication frame still is not “indicative of a desired transmit
power level change in the first client device” as that term is
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properly construed. That is, the access point in Adachi does not
transmit a beacon packet and an authentication frame that have
transmit power levels the difference of which indicates a
desired transmit power change in the station. Instead, the
access point in Adachi transmits a beacon packet and an
authentication frame that have transmit power levels that have
nothing to do with the desired transmit power change in the
station and the station then receives the signals, measures the
receive powers, reads the transmit powers, and then uses the
transmit powers and receive powers to determine whether
SDMA was used by the AP to transmit the authentication
frame. If it is determined that SDMA was used, then the
transmit power level of the station will be modified.

(Br. 15.)
This argument reduces to the assertion that the Examiner found that
the “transmit power level of the station [i.e., “a first client device,” as set
forth in claim 1] will be modified” based on “the transmit powers and
receive powers” of the beacon packet (i.e., “a first packet” in claim 1) and an
authentication packet frame (i.e., “a second packet” in claim 1). As the
claim does not preclude using extra information (such as the receive powers
of the packets) to control the transmit power, Appellant’s arguments fail to
demonstrate error. The transmit powers are “indicative” of the desired
change even if they do not solely determine the desired power change.
In other words, open-ended claim 1 does not preclude the recited first
and second transmit power levels from collectively indicating – i.e., with
measured received power levels – a desired client power change.
Appellants’ Specification does not employ the term “indicative.” Further,
Appellants’ disclosed systems rely on additional information, such as the
measured received power of the client device (FF 4), or the measured
received power of the transmitted packets (FF 5), to cause a desired client
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power change. Thus, like Adachi’s system (FF 1), Appellants’ disclosed
transmitted packet information (FF 4, 5) is indicative of a desired change
when combined with, or in the context of, other known or measured power
information.
This claim interpretation, whereby the transmitted power level
information is collectively indicative (of a desired change) with the received
power level information, is also consistent with known meanings and uses of
the term “indicate.”3 The term “indicate” carries with it an assumption that
indicative information is indicative in context with other information or
constraints. (For example, the statement “his reply indicates his
disapproval” implies that a previous remark exists – without information
about the specific remark, the reply may be meaningless.) Contrary to
Appellant’s arguments, then, claim 1 does not preclude other information
such as received power information.
As Adachi states, “[i]t is possible to precisely estimate the gain of the
directional beam by considering the transmitted power information for the
directional beam and the transmitted power information for the non-
directional beam.” (FF 1 (emphasis added).) The STAs then use the gain to
set the desired power. (FF 1.) Thus, the transmitted power information is
indicative of the desired change.
Skilled artisans would have understood, from Adachi’s disclosure,
that measuring received power allows a STA to make an accurate

3 The term “indicate” is defined as “[t]o serve as a sign, symptom, or token
of: SIGNIFY.” Webster’s II New Riverside Dictionary 622-23 (1984). An
“indicator” is defined as “[a]ny of various statistical values that collectively
indicate the stability of an economic system.” Id. at 623 (emphasis added).
,
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measurement of transmitter gain in order to set the STA power accordingly.
Skilled artisans also would have understood that merely using and
comparing the transmitted power of two successive packets (one known to
be directional and the other known to be non-directional based on the packet
type and/or defaults), also allows a STA to determine gain and set the STA
power accordingly, albeit with less accuracy (and less processing as a trade-
off).4 (See FF 1.)
Thus, assuming for the sake of argument that claim 1 requires the
transmitted packet levels to be indicative of the desired power level change
without the received power information as Appellant argues, Adachi at least
suggests a less accurate and simpler embodiment (in addition to the more
accurate embodiment referenced in Appellants’ argument supra) which
satisfies this claim interpretation. In the less accurate embodiment, Adachi’s
AP controller 14 transmits beacon and unicast packets which carry both
power information and the packet type. In other words, the second packet
type, the unicast packet, indicates directional control (i.e., without the STAs
measuring received power). Consequently, comparing the transmitted
power in the two packets indicates the desired power level change. (For
example, steps S202 and S203 are skipped in Figure 8. An STA can

4 A moving STA receives the same transmitter power information from the
AP regardless of the relative differences in distance with respect to the AP.
Thus, without the received power information (or some other information) to
account for these different relative differences, a moving STA (or two
differently located STAs) would theoretically set power at the same setting
even as distance to the AP varies. Such a power setting may suffice over
shorter distance variations, but would be less useful than accurately
accounting for the different distances with received power measurements (as
measured at either the STAs or the AP). Apparently, Appellants use
received power information for a similar reason. (See FF 4, 5.)
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determine which frames are unicast or broadcast, assume a unicast frame is
directional, and/or assume its directional extent based on a pre-set default
level – FF 1.) Finally, in step S204, based on the transmitted power level
information in the non-directional beacon frame and directional unicast
frame (transmitted from the AP controller), the STAs can set power to a
predetermined level. (FF 1; see also note 4 supra.)
To the extent Appellants argue (supra and in other places) that Adachi
does not employ measurements based on “a difference in decibels,” as set
forth in claim 1, this argument is also unconvincing. First, Adachi employs
a difference in transmit power and a difference in receive power, between
first and second packets, to make the desired transmit power change.
Therefore, this difference in power is inherently a difference in decibels,
because such a difference merely constitutes a measure of relative power.
(Claim 1 does not require any processing of numbers expressed as decibels.)
Second, even if the claim requires the processing of numbers expressed in
decibels, Adachi teaches sending relative power information in numbers,
which suggests processing in the well-known unit of decibels. (FF 1.)5
Finally, Appellants’ arguments do not demonstrate error in the Examiner’s
rationale of using the well-known unit of decibels as an obvious
modification based on Larson’s teachings. (FF 3; Ans. 5.)
To the extent that Appellants argue (Br. 13-14) that the claim requires
the control unit to reside in the AP, and not the client device, claim 1
requires the control unit to cause packets having different power levels to be

5 The well-known term “decibel” is defined as “[a] unit for expressing
relative difference in power, usu. between acoustic or electric signals, equal
to ten times the common logarithm of the ratio of the two levels.” Webster’s
II New Riverside University Dictionary 352 (1984).
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sent. Adachi’s AP transmitting station contains a control unit 14 which
causes the packets to be sent. The packets carry power information
indicative of a desired power change as claim 1 also requires. (FF 1.)
Appellants’ related argument (Br. 13-14) that Adachi’s wireless
stations (STAs) process the desired power change does not defeat the finding
related to the AP power control. The AP power controller 14 “manage[s]
transmit power control activities” (by transmitting the recited first and
second packets) as required by claim 1. Moreover, Larson cumulatively
teaches a control unit in an AP. (Ans. 4-5.)
Appellants also argue that the Examiner’s rationale merely identified
an end result and therefor does not support obviousness. (Br. 16.) This
argument is not convincing. The Examiner’s “result” includes the rationale
behind the modification – to provide control of the desired power in the
client device (i.e., the STA). (See Ans. 5.) Moreover, Adachi satisfies the
claim without Larsson’s cumulative teachings. That is, Adachi’s AP
includes a power control unit 14, as noted above, and a transmitter/receiver
system (FF 1), the latter satisfying the wireless transceiver element recited in
claim 1. See In re Meyer, 599 F.2d 1026, 1031 (CCPA 1979) (noting that
obviousness rejections can be based on references that happen to anticipate
the claimed subject matter.)
Appellants’ argument (App. Br. 16) that the Examiner did not identify
the differences between the prior art and claim 1 is also unavailing. The
Examiner detailed the differences on pages 4 and 5 of the Answer. In any
event, as indicated above, Larrson’s teachings are cumulative to Adachi’s,
and claim 1 does not recite a patentable distinction thereover. That Larsson
and Adachi disclose similar (i.e., cumulative claimed elements) systems also
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defeats Appellants’ conclusory argument (App. Br. 17) that the two systems
are “very different.”
Appellants’ argument (App. Br. 17) that changing between the non-
SDMA and SDMA channels would eliminate the power level change
information carried by the two packets in claim 1, incorrectly implies that
Adachi’s system would not function. Adachi discloses a functioning SDMA
system, and notes that SDMA directive beam systems decrease interference
between multiple STAs, suggesting an improvement to Larsson’s wireless
power control system which also mitigates interference. (FF 1, 3.)
Based on the foregoing discussion, Appellants have not demonstrated
error in the rejection of claim 1 and claims 25-28 falling therewith as not
separately argued. (See Br. 27-28.)
Claims 8 and 29
Appellants present arguments similar to those presented against the
rejection of claim 1. (Br. 17-18.) Based on the foregoing discussion of
claim 1, Appellants have failed to demonstrate error in the rejection of
claims 8 and 29.
Claim 17
Appellants present arguments similar to those presented against the
rejection of claim 1. (Br. 18-20.) In addition, Appellants argue that
Adachi’s first and second packets are not transmitted through “substantially
the same channel,” as required by claim 17, because the second packet
travels through an SDMA channel. (Br. 19.) Appellants present no
evidence to support the assertion that the two channels are not “substantially
the same channel.”
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Nor do Appellants define the phrase “substantially the same channel”
as required to distinguish claim 17 and meet the burden on appeal of
demonstrating error. Rather, in a separate argument, Appellants indicate that
the phrase merely indicates that “there is little or no change in the condition
of the channel during the transmit power control packet exchange.” (Br. 9
(addressing the Examiner’s withdrawn rejection based on written
description).) Such relative terms (i.e., “substantially”) do not define over
Adachi’s system which also sends packets relatively closely in time for
similar power measurements. (FF 1.) “It is the applicants’ burden to
precisely define the invention, not the PTO’s.” In re Morris, 127 F.3d 1048,
1056 (Fed. Cir. 1997). “The problem in this case is that the appellants failed
to make their intended meaning explicitly clear.” Id.
Further, Adachi describes the adaptive SDMA antenna array scheme
as allowing for simultaneous communication to multiple STAs over the
same channel. This implies crowded channel conditions, thereby further
suggesting that successive beacon and authentication packets may share
“substantially” the same physical channel. (FF 2.) In addition, Adachi’s
system must determine whether or not a beacon frame or SDMA frame is
sent by exploiting packet header information. This indicates that both frame
types are transmitted in the same channel. (FF 1.) (Otherwise, the different
channels would signify different frame types – inspecting the header for
frame type would be superfluous.)
Based on the foregoing, including the discussion of claim 1,
Appellants have failed to demonstrate error in the rejection of claim 17.

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Claim 34
Appellants argue inter alia that “the technique described in Larsson
does not provide a means for a station to autonomously request transmit
power level information from an AP. . . . Adachi was only cited because it
mentions SDMA mode operation.” (Br. 21.) Appellants similarly argue that
Larsson does not teach the IEEE 802.11h TPC (transmit power control)
request and report packets recited in claim 34. Finally, Appellants assert a
lack of “some articulated reasoning with some rational underpinning to
support the legal conclusion of obviousness.” (Br. 21 (quoting KSR (which
quotes Kahn) - pin cites omitted by Appellants, see cites and quotation
supra).)
The Examiner first reasoned that Larsson discloses receiving the IEEE
802.11h TPC request packet at an access point, as claim 34 requires, at
paragraphs 011 and 100 and Figure 8. (Ans. 8.) However, inspection of the
cited passages and figure reveals that Larsson neither discloses this
particular request packet, nor any request packet arriving at an access point.
In response to Appellants’ arguments, the Examiner shifted the
original rationale and asserted that Adachi teaches not only SDMA, but also
“power control in which the client device extracts the transmitting power . . .
from the access point . . . and [t]he client device sets the power accordingly.”
(Ans. 13.) The Examiner further modified the original rejection and
reasoned that Larsson merely teaches the specific IEEE 802.11h protocol.
However, neither the Examiner’s original nor shifted rationale points
to any clear reference to a TPC request packet from a wireless device.
Under these circumstances, Appellants have demonstrated error in the
Examiner’s rejection of claim 34.
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Claim 39
Similar to claim 34, claim 39 requires sending an IEEE 802.11h TPC
request packet to an access point. In response to Appellants’ arguments, the
Examiner states: “Regarding claim 39, the argument is the same as claim 34
above, more specifically Larsson teaching a close loop power control (par.
029, 080) with a path gain based on measured signal strength (par.0100),
wherein a path gain based on measured signal strength is associated with
transmission range (par.0103).” (Ans. 13.) The Examiner’s response
correctly notes that Appellants’ arguments for claim 39 track those for claim
34. (See Br. 25-27.)
However, like the Examiner’s responses with respect to claim 34, this
response does not point to the specific recitations in claim 39, including inter
alia, the TPC request packet sent to an access point. Therefore, the
Examiner’s response does not constitute “some articulated reasoning with
some rational underpinning to support the legal conclusion of obviousness.”
In re Kahn, 441 F.3d at 988. (Accord Br. 26.) While the Examiner points to
column 2, lines 20-25 of Adachi to teach sending a transmit power control
(TPC) request packet to an access point (Ans. 9), no such teaching clearly
emerges from that passage. Based on the foregoing discussion, including
that involving claim 34, Appellants have demonstrated error in the rejection
of claim 39.

Claims 4, 13, 21, and 32
Appellants assert allowability of these claims based on their
dependence from claims 1, 8, 17, and 29. (Br. 22.) Appellants also assert
that these claims are patentable because “Larsson and Adachi would not
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make it obvious . . . to use an RTS packet followed by a null packet . . . .”
(Br. 23.) Inasmuch as these claims do not recite a null packet, and based on
the foregoing discussion involving claims 1, 8, 17, and 29, Appellants’
arguments do not demonstrate error in the rejection of claims 4, 13, 21, and
32.
Claims 7, 16, and 20
Claim 7 follows:
7. The wireless AP of claim 1, wherein:
said desired transmit power level change in the first client device is
indicated by a sign of said difference between said first transmit power level
and said second transmit power level, wherein said desired transmit power
level change is X decibels when said sign is positive and -X decibels when
said sign is negative, where X is a predetermined increment or decrement
value.
Appellants’ arguments focus on claim 7. (Br. 23-24.) The Examiner
takes official notice that “the concept of the transmit power level +X and –X
decibels increment or decrement value is known in the art.” (Ans. 6.)
Appellants traverse this official notice, but state that “even if it were
assumed, just for the sake of argument, that transmit power level increments
and decrements were known, the cited references still do not teach or
suggest the use of the sign of the difference in decibels between the transmit
power levels of two transmitted packets to determine whether to increase or
decrease transmit power by X.” (Br. 23-24.)
The Examiner’s explanation does not clearly articulate how to arrive
at the claimed invention. For example, Adachi teaches that, if anything, the
sign of the difference would result in the opposite of what is claimed. In
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other words, if the transmitted power increases in successive pulses by 1, but
the measured received power increases by 2, this indicates that the access
point is not performing beacon control, and thus, power of the wireless
station is correspondingly decreased. (Adachi, col. 11, ll. 24-33; col. 12, ll.
1-5.) Hence, Appellants’ arguments demonstrate error in the Examiner’s
rejection of claim 7. Claim 20, reciting a sum with a sign, requires similar
limitations. Therefore, based on the foregoing discussion, claim 20 is
treated like claim 7.
In contrast, claim 16 recites broader limitations, notwithstanding
Appellants’ reliance on arguments against the rejection of claim 7. Claim 16
follows:
16. The method of claim 8, wherein:
said difference between said first transmit power level and said
second transmit power level is indicative of a desired direction of
change of the transmit power level of the remote client device.
Based on the discussion supra involving claim 1, Adachi does teach
an indication of the desired direction of change. For example, an increase in
transmitted power indicates at least in some situations (along with the
received power), a desire to decrease the remote client device power. (See
also id.)
Therefore, Appellants’ arguments demonstrate error in the rejection of
claims 7 and 20, but not claim 16.
Claim 19
Claim 19 follows:
19. The method of claim 17, wherein:
modifying a transmit power level includes
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determining a sum of said difference and a present transmit
power level.
Appellants argue that Adachi uses the received and transmitted power
to determine how to modify a transmit power level. (Br. 24.) (Claim 19,
depending from claim 17, requires the step of measuring received power.)
The Examiner asserts that “the comparison of the first and second signal
mathematically to conclude the difference corresponds to a sum of said
difference.” (Ans. 6.) However, as Appellants indicate, Adachi’s (more
accurate, see note 4 supra) system uses more than just the transmit power to
determine how to change the power of the client device. The Examiner has
not clearly articulated how the proposed modification of Adachi arrives at
the claimed invention. Claim 19 requires a sum involving the access point
transmitted power difference and what is interpreted (in claim 19) to be the
client device “present transmit power level,” to modify the client device
transmit power level. Therefore, Appellants’ arguments demonstrate error in
the rejection of claim 19.
Claims 2-3, 9-12, 18, 22, 31, 35-38, and 40-41
With respect to these dependent claims, Appellants rely on arguments
presented for independent claims 1, 8, 17, 29, 34, and 39. (Br. 24-25, 27.)
Based on the foregoing discussion, claims 2-3, 9-12, 18, 22, and 31 fall with
claims 1, 8, 17, and 29, while claims 35-38 and 40-41 stand with claims 34
and 39. In re Nielson, 816 F.2d 1567, 1572 (Fed. Cir. 1987); 37 C.F.R. §
41.37(c)(1)(vii).
CONCLUSION
Appellants did not demonstrate that the Examiner erred in finding that
Larsson and Adachi collectively teach “a first packet having a first transmit
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power level and a second packet having a second transmit power level,
wherein a difference in decibels between the first transmit power level and
the second transmit power level is indicative of a desired transmit power
level change in the first client device,” as set forth in claim 1.
Appellants did demonstrate that the Examiner erred in finding that
Larsson and Adachi collectively teach receiving an IEEE 802.11h transmit
power control (TPC) packet from a wireless device at a wireless access
point, as set forth in claims 34 and 39.
Appellants did not demonstrate error in the Examiner’s rationale
related to the manner of power control as set forth in claim 16, but did
demonstrate error in the rationale related to power control as set forth in
claims 7, 19, and 20.

DECISION
We affirm the Examiner’s decision rejecting claims 1-4, 8-13, 16-18,
21, 22, 25-29, 31, and 32. We reverse the Examiner’s decision rejecting
claims 7, 19, 20, and 34-41.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136. See 37 C.F.R.
§ 1.136(a)(1)(iv).
AFFIRMED

rvs

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