Ex Parte Kahola

Board of Patent Appeals and Interferences

Nov 9, 2009

10033451 (B.P.A.I. Nov. 9, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte MIKA KAHOLA
____________

Appeal 2009-002894
Application 10/033,451
Technology Center 2100
____________

Decided: November 9, 2009
____________

Before JOHN A. JEFFERY, ST. JOHN COURTENAY III, and
JAMES R. HUGHES, Administrative Patent Judges.

JEFFERY, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 2-17. We have jurisdiction under 35 U.S.C. § 6(b). We
affirm.

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STATEMENT OF THE CASE
Appellant invented a link adaptation method for a wireless
communication system. Specifically, packets are formed from the
information to be transferred between two communication devices, and a
packet error rate is defined. A modulation mode is selected from plural
modulation modes using fuzzy control where the packet error rate is used as
a fuzzy control variable.1 Claim 17 is illustrative with the key disputed
limitations emphasized:
17. A method for performing link adaptation in a communication
system, the method comprising

forming a connection to transfer information at least partly wirelessly
between two communication devices;

forming packets from the information to be transferred via the
connection, said packets comprising a header and a payload;

determining a packet error rate; and

selecting a modulation mode for the connection from at least two
different modulation modes;

wherein said selecting a modulation mode comprises using fuzzy
control; and using said packet error rate as one variable for said fuzzy
control.

The Examiner relies on the following as evidence of unpatentability:
Lewis US 5,687,290 Nov. 11, 1997
Agrawal US 6,072,990 June 6, 2000
La Porta US 6,654,359 B1 Nov. 25, 2003
(filed Dec. 11, 1998)

1 See generally Abstract; Spec. 4-6; Fig. 3b.
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The Rejection
The Examiner rejected claims 2-17 under 35 U.S.C. § 103(a) as
unpatentable over Agrawal, La Porta, and Lewis. Ans. 4-10.2
Regarding representative claim 17,3 the Examiner finds that Agrawal
discloses a link adaptation method that selects a modulation mode from
multiple modulation modes by virtue of Agrawal’s selection of encoding
schemes. Ans. 8, 9, and 11. The Examiner also equates Agrawal’s
determination of word error rate with determining packet error rate as
claimed. Ans. 8, 9, 15, and 16.
Based on these teachings, the Examiner finds that Agrawal discloses
every recited step of claim 17 except for:
(1) forming packets from information to be transferred;
(2) selecting a modulation mode using fuzzy control; and
(3) using packet error rate as a fuzzy control variable.
The Examiner, however, relies on (1) La Porta to cure the first noted
deficiency, and (2) Lewis to cure the second and third deficiencies in
concluding that the claim would have been obvious. Ans. 9-10.
Appellant makes three main arguments. First, Appellant argues that
Agrawal does not teach selecting a modulation mode as claimed since
Agrawal’s system involves “significantly different parameters” than the
modulation mode selection of the claimed invention, namely transmission

2 Throughout this opinion, we refer to the Appeal Brief filed August 9, 2007
and the Examiner’s Answer mailed November 1, 2007.

3 Appellants argue claims 2-17 together as a group. See Br. 9-13.
Accordingly, we select independent claim 17 as representative. See 37
C.F.R. § 41.37(c)(1)(vii).
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power and/or error code. Appellant contrasts these parameters with those
used in the claimed modulation mode selection, namely data speed,
modulation method, coding rate, etc. Br. 9-10.
Second, Appellant argues that Agrawal teaches away from combining
its teachings with Lewis as the Examiner proposes. According to Appellant,
since Agrawal’s purpose in selecting a power code pair is to limit overhead
resources needed for this selection, a more flexible approach (e.g., using
fuzzy logic principles as in Lewis) would not be needed, and actually runs
counter to Agrawal’s purpose. Br. 10.
Third, although Appellant acknowledges that it is known to form a
packet with a header and a payload, Appellant argues that Agrawal’s word
error rate is not equivalent to packet error rate, but rather bit error rate. Br.
10-13. As such, Appellant contends, skilled artisans would not consider
Agrawal’s word error rate equivalent to packet error rate—a conclusion that
is said to be supported by two publication abstracts in the Evidence
Appendix. Br. 12-13.
The issues before us, then, are as follows:

ISSUES
1. Under § 103, has Appellant shown that the Examiner erred in
rejecting claim 17 by finding that Agrawal, La Porta, and Lewis collectively
teach or suggest:
(a) determining a packet error rate;
(b) selecting a modulation mode from multiple modulation modes,
where the selection uses fuzzy control; and
(c) using packet error rate as a fuzzy control variable?
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2. Under § 103, has Appellant shown that the Examiner erred in
combining the respective teachings of Agrawal, La Porta, and Lewis to
arrive at the claimed invention? This issue turns on whether Agrawal
teaches away from combining its teachings with Lewis.

FINDINGS OF FACT
The record supports the following findings of fact (FF) by a
preponderance of the evidence:
Agrawal
1. Agrawal’s system adaptively determines an operating point for a
transmitter 12 and receiver 13 that communicate via a wireless link 11. The
operating point is a tradeoff between (1) the amount of control overhead
used by the channel associated with the link, and (2) the resulting channel
quality. Agrawal, Abstract; col. 4, ll. 18-26; col. 5, ll. 29-64; Fig. 1.
2. Transmitter 12 encodes transmitted data using a forward error
correcting (FEC) encoding scheme selected from plural encoding schemes
represented by C = {c0, c1, . . . , cn} and stored in the transmitter’s memory
15. Agrawal, col. 5, l. 65 − col. 6, l. 2; Fig. 1.
3. At any point during the channel’s lifetime, the transmitter’s
operating point is defined by a set of transmission parameters, namely a
power-code pair (P,c) where “P” defines the transmitter’s current transmit
power, and “c” identifies the current FEC encoding scheme. Agrawal, col.
6, ll. 3-8; Fig. 1.

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4. Receiver 13 monitors and measures (1) the received power level;
(2) the word error rate (WER); and (3) the link’s interference level. At the
end of each “timeframe,”4 the receiver checks these values and, if
unacceptable, sends a message to the transmitter with these values and the
desired WER. Upon receipt, the transmitter uses these values to determine a
new power-code pair that will be used during the next timeframe. Agrawal,
col 6, ll. 9-40; Fig. 1.
5. In the Background of the Invention section, Agrawal notes that
measures have been taken to maintain transmission quality over a radio
channel. These measures typically try to control various channel quality
metrics (e.g., error rates, carrier-to-interference ratios (CIRs), bandwidth,
etc.) by controlling various channel transmission parameters (e.g.,
transmission power, FEC, etc.). Agrawal, col. 1, ll. 27-47.
6. Agrawal further notes that the effective bit error rate (BER) for
digital transmissions depends on the modulation scheme used. To exemplify
this dependence, Agrawal describes the relationship between CIR and BER
for binary phase shift key (BPSK) modulation and represents this
relationship mathematically in Equation (2). Agrawal, col. 1, ll. 48-60.
7. According to Agrawal, data transmission is usually packetized into
words so that error granularity is at the word level. Thus, for a given BER,
the observed WER depends on the type of FEC scheme used. As such, each

4 A “timeframe” is the time period between successive iterations in which
the transmitter and receiver collaborate to evaluate channel performance.
The timeframe is preferably at least as long as needed to obtain reasonable
estimates for the measurements. Agrawal, col. 6, ll. 18-30.
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connection in a wireless system has an associated reliability constraint
expressed as (1) a desired WER, and (2) a range of acceptable WERs.
Agrawal, col. 1, l. 54 − col. 2, l. 12.
7A. An important factor in adaptive control of a wireless channel
connection is the overhead associated with performing the control.
Generally, if maintaining a required channel quality requires frequent
control parameter changes for power and coding, the control approach may
not be worth the result. Agrawal, col. 8, ll. 3-26.

La Porta
8. The Examiner’s findings regarding La Porta’s disclosure (Ans. 9
and 12) are undisputed. See Br. 10-11.

Lewis
9. Lewis discloses a system for monitoring and controlling
communication networks comprising a network monitoring system 12
connected to a local area network (LAN) 8 via communications link 14.
Network monitoring system 12 is also connected to a fuzzy logic control
system 18 via communications link 16. Lewis, col. 4, ll. 52-60; Fig. 2.
10. Network monitoring system 12 includes (1) a configuration
management module 20, and (2) a network monitor module 22. The
network monitor module (a) monitors LAN 8 to detect changes in network
operation parameters and control the network, and (b) transmits information
concerning network operation parameters to fuzzy logic control system 18.
Lewis, col. 5, ll. 20-35; Fig. 2.
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11. Fuzzy logic control system 18 includes a “fuzzifier” module 26
that (1) receives values of monitored network parameters in the form of
numeric data, and (2) translates this numeric data into a description language
to provide fuzzy input data. This input data is then sent to a fuzzy inference
engine 28 which (1) processes the data in accordance with at least one stored
fuzzy rule, and (2) generates fuzzy output data that is used to control the
LAN’s parameters. This output data is then sent to a “defuzzifier” module
46 that (1) converts the data back into numeric data, and (2) transmits the
numeric data to the configuration management module 20 to control LAN 8.
Lewis, col. 5, l. 36 − col. 6, l. 4; Fig. 2. A block diagram of Lewis’ network
monitoring and control system is shown in Figure 2 reproduced below:

Lewis’ Network Monitoring and Control System in Figure 2

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12. Lewis notes that membership functions for linguistic values of
variables representing network monitoring system 12 can be defined, such as
packet_collision_rate, packet transmission rate, packet_deferment_rate, etc.
Once the membership functions are defined, then fuzzy rules are defined that
connect fuzzy input and output variables. Lewis, col. 7, l. 63 − col. 8, l. 28.

Appellant’s Disclosure
13. “It is known that different packet error rates (PER) can be
attained with different modulation modes in situations in which the signal to
interference ratio (s/i) is constant.” Spec. 2:13-16.

PRINCIPLES OF LAW
In rejecting claims under 35 U.S.C. § 103, it is incumbent upon the
Examiner to establish a factual basis to support the legal conclusion of
obviousness. See In re Fine, 837 F.2d 1071, 1073 (Fed. Cir. 1988). If the
Examiner’s burden is met, the burden then shifts to the Appellant to
overcome the prima facie case with argument and/or evidence. Obviousness
is then determined on the basis of the evidence as a whole and the relative
persuasiveness of the arguments. See In re Oetiker, 977 F.2d 1443, 1445
(Fed. Cir. 1992).
To be patentable under § 103, an improvement must be more than the
predictable use of prior art elements according to their established functions.
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007).
“[W]hen the prior art teaches away from combining certain known
elements, discovery of a successful means of combining them is more likely
to be nonobvious.” Id. at 416.
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“A reference may be said to teach away when a person of ordinary
skill, upon reading the reference, would be discouraged from following the
path set out in the reference, or would be led in a direction divergent from
the path that was taken by the applicant.” In re Kahn, 441 F.3d 977, 990
(Fed. Cir. 2006) (citations and internal quotation marks omitted).

ANALYSIS
Based on the record before us, we find no error in the Examiner’s
obviousness rejection of representative claim 17.
First, we agree with the Examiner (Ans. 11) that Agrawal’s selecting a
particular encoding scheme from plural encoding schemes (FF 2) reasonably
corresponds to selecting a modulation mode as claimed. As the Examiner
indicates, modulation pertains to how data is coded to send it through a
transmission medium (Ans. 11)—a technique that reasonably comports with
Agrawal’s FEC encoding scheme that the transmitter uses to encode data
sent to the receiver via a channel associated with a wireless link. See FF 1-3.
Even assuming that Agrawal uses different parameters in this
selection as compared to the invention as Appellants argue (Br. 10), claim
17 does not require the particular parameters that Appellant indicates
distinguish the invention from Agrawal. All the claim requires in this regard
is that a modulation mode be selected from multiple modulation modes—a
limitation whose scope does not preclude Agrawal’s selecting an encoding
scheme that is based on transmission parameters to determine an appropriate

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operating point. See FF 3-4. We therefore agree with the Examiner that
Agrawal’s selecting a particular encoding scheme from plural encoding
schemes (FF 2) reasonably corresponds to selecting a modulation mode as
claimed.
To be sure, Agrawal’s receiver monitors and measures the word error
rate (WER) that the transmitter then uses as a basis to determine a new
power-code pair (FF 4). As such, Agrawal does not explicitly state that the
packet error rate is used in this process. See id. Nevertheless, we agree with
the Examiner (Ans. 15-16) that Agrawal’s WER determination at least
suggests a packet error rate determination.
Although Agrawal represents an error rate for BPSK modulation in
terms of bit error rate (BER) and CIR in the Background section (FF 6),
Agrawal nevertheless indicates that data transmission is usually packetized
into words so that error granularity is at the word level (FF 7; emphasis
added). Thus, for a given BER, the observed WER depends on the type of
FEC scheme used. Id.
Agrawal’s word choice here is telling: the term “packetized” all but
indicates that the words are associated with some form of data packet. See
id. Indeed, as blocks of data, the words themselves could be reasonably
construed as “packets” given the import of this passage. See id.
Therefore, skilled artisans would have reasonably inferred from
Agrawal that an error rate associated with words (e.g., WER) would at least
be associated with an error rate associated with corresponding packets (i.e., a
“packet error rate”). Notably, Appellant does not define the term “packet

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error rate” in the Specification and, as such, Agrawal’s WER reasonably
corresponds to a “packet error rate” under the term’s broadest reasonable
interpretation. The Examiner’s point in this regard (Ans. 16) is well taken.
Appellant relies heavily on Agrawal’s expressing WER in terms of
BER to support the contention that Agrawal’s WER is equivalent to BER—
not packet error rate. Br. 11-13. Appellant also cites two publication
abstracts in the Brief’s Evidence Appendix that are said to support the
proposition that packet error rate is not equivalent to WER or BER.
Br. 12-13; Ev. App’x.
These arguments are unavailing. First, as we indicated previously,
nothing in claim 17 precludes Agrawal’s WER from corresponding to a
“packet error rate” under the term’s broadest reasonable interpretation. As
such, even assuming that Agrawal’s WER can be expressed in terms of BER
(see FF 6-7), this WER nonetheless fully meets a “packet error rate” given
the scope and breadth of the term.
Second, even if we assume, for the sake of argument, that Agrawal’s
WER somehow does not meet a “packet error rate” as claimed, the fact that
Agrawal’s WER is described in connection with an associated BER (see id.)
is hardly dispositive of whether it would also have an associated packet error
rate.
In this regard, the cited abstracts in the Evidence Appendix are not
persuasive. Although the first abstract (“Abstract 1”) concludes that BER is
not a good indicator of packet error (and vice-versa) based on comparative
test results (Br. 21; Ev. App’x), this conclusion hardly means that
determining a packet error rate would not have been an obvious
improvement over determining BER or WER in Agrawal.
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We reach a similar conclusion regarding the second abstract
(“Abstract 2”) which indicates that the analysis of BER with respect to a
wireless network’s mean behavior is insufficient in packet error rate
evaluations (Br. 21-22; Ev. App’x). Here again, the fact that BER may be
insufficient in packet error rate evaluations hardly means that determining
packet error rate is a nonobvious improvement over determining WER or
BER in Agrawal. If anything, the articles tend to suggest the opposite since
they readily acknowledge that packet error rate—like BER—is a well-
known metric in evaluating data transmission. That Appellant indicates in
the Specification that it is known to obtain packet error rates (FF 13) only
bolsters this conclusion.
In any event, we find that determining packet error rate in lieu of
WER or BER in Agrawal is tantamount to the predictable use of prior art
elements according to their established functions—an obvious improvement.
See KSR, 550 U.S. at 417. Moreover, Appellant has provided no evidence
on this record establishing that determining packet error rate in lieu of WER
or BER in Agrawal would have been an improvement beyond the level of
skilled artisans. See id. (“[I]f a technique has been used to improve one
device, and a person of ordinary skill in the art would recognize that it would
improve similar devices in the same way, using the technique is obvious
unless its actual application is beyond his or her skill.”).
Nor are we persuaded that the Examiner erred in combining the
teachings of La Porta and Lewis with Agrawal to arrive at the claimed
invention. Notably, the Examiner’s findings regarding La Porta’s disclosure
pertaining to forming packets are undisputed (FF 8). Indeed, Appellant
admits that forming packets with a header and payload for routing is well
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known. Br. 11. As such, we see no reason why this teaching could not be
applied to Agrawal’s data transmission system to form packets with a header
and a payload from the information to be transferred.
We also find no error in the Examiner’s combining Lewis’ teachings
of a fuzzy control system with Agrawal. Significantly, Lewis’ fuzzy logic
control system operates in conjunction with a network monitoring system to
perform network monitoring and control functions in accordance with fuzzy
control principles (i.e., using fuzzy rules and fuzzy data processing
techniques). FF 9-12. Notably, membership functions for linguistic values
of variables representing the network monitoring system associated with
Lewis’ fuzzy control system can be defined in terms of packet characteristics
and errors (e.g., packet collision rate). FF 12. Lewis therefore at least
suggests using packet error rate as a fuzzy control variable.
Based on these teachings, we see no reason why Agrawal’s
modulation mode selection could not utilize a fuzzy control system such as
that disclosed by Lewis, particularly since both references pertain to
monitoring and controlling parameters associated with a data
communications system. Compare FF 1-4 with FF 9-11. Such an
enhancement is tantamount to the predictable use of prior art elements
according to their established functions—an obvious improvement. See
KSR, 550 U.S. at 417.
Nor does Agrawal teach away from such an approach. To be sure,
Agrawal does indicate that overhead is an important factor in adaptive
control, and that frequent control parameter changes can be detrimental and
not worth the result. FF 7A. As such, limiting overhead would be an
important consideration in Agrawal’s system as Appellant argues (Br. 10).
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But ultimately, the operating point in Agrawal is a tradeoff between
(1) the amount of control overhead used by the channel associated with the
link, and (2) the resulting channel quality. FF 1. Therefore, even assuming,
without deciding, that using a fuzzy logic control system such as that
disclosed by Lewis in Agrawal’s system increases control overhead (a
finding that has not been made on this record in any event), such a drawback
could very well be offset by the advantages in channel quality obtained via a
fuzzy control system. Such an engineering decision would be well within
the level of ordinarily skilled artisans.
As such, skilled artisans would not be discouraged from following the
path set out in Agrawal and Lewis, nor would they be led in a direction
divergent from the path that was taken by Appellant. See Kahn, 441 F.3d at
990. Accordingly, we do not find that Agrawal teaches away from its
combination with Lewis to arrive at the claimed invention as the Examiner
proposes.
For the foregoing reasons, Appellant has not persuaded us of error in
the Examiner’s rejection of representative claim 17. Therefore, we will
sustain the Examiner’s rejection of that claim, and claims 2-16 which fall
with claim 17.

CONCLUSION
Appellant has not shown that the Examiner erred in rejecting claims
2-17 under § 103.

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ORDER
The Examiner’s decision rejecting claims 2-17 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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