Ex Parte Narasimhan

Board of Patent Appeals and Interferences

Jul 21, 2008

10656001 (B.P.A.I. Jul. 21, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte RAVI NARASIMHAN
____________

Appeal 2008-1203
Application 10/656,001
Technology Center 2600
____________

Decided: July 21, 2008
____________

Before KENNETH W. HAIRSTON, MAHSHID D. SAADAT,
and JOHN A. JEFFERY, Administrative Patent Judges.

JEFFERY, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134 from the Examiner’s
rejection of claims 2, 4-8, 10, 13, 15-19, 21, 24, 26-30, 32, 35, 37-41, 43, 46,
48-52, 54, and 57. Claims 9, 11, 20, 22, 31, 33, 42, 44, 53, 55, 58, and 59
have been indicated as containing allowable subject matter (Ans. 13; App.
Br. 2). We have jurisdiction under 35 U.S.C. § 6(b). We affirm-in-part.

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STATEMENT OF THE CASE
Appellant invented an antenna selection scheme for a multiple-in
multiple-out (MIMO) communication system. The optimum number of
antennas is selected for communication over correlated fading channels
based on second-order statistics.1 Claims 4 and 7 are illustrative:

4. A method comprising:

selecting a subset of active antennas from a plurality of available
antennas in a multi-element antenna system based on higher-order statistics
of a propagation medium; and

selecting a constellation for transmission on the active antennas,
where said selecting the constellation for transmission on the active antennas
comprises selecting different constellations for two or more of the active
antennas.

7. A method comprising:

selecting a subset of active antennas from a plurality of available
antennas in a multi-element antenna system based on higher-order statistics
of a propagation medium, where said selecting comprises selecting an
optimum number of antennas to maximize a minimum signal-to-noise ratio
(SNR) margin.

The Examiner relies on the following prior art references to show
unpatentability:
Malaender US 2003/0223391 A1 Dec. 4, 2003
(filed Jun. 4, 2002)
Kadous US 6,801,580 B2 Oct. 5, 2004
(filed Apr. 9, 2002)

1 See generally Abstract; Spec. ¶¶ 0004-05.
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Claims 2, 4-8, 10, 13, 15-19, 21, 24, 26-30, 32, 35, 37-41, 43, 46, 48-
52, 54, and 57 stand rejected under 35 U.S.C. § 103(a) as unpatentable over
Malaender and Kadous (Ans. 3-12).
Rather than repeat the arguments of Appellant or the Examiner, we
refer to the Briefs and the Answer for their respective details. In this
decision, we have considered only those arguments actually made by
Appellant. Arguments which Appellant could have made but did not make
in the Briefs have not been considered and are deemed to be waived. See
37 C.F.R. § 41.37(c)(1)(vii).

OPINION
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). In so
doing, the Examiner must make the factual determinations set forth in
Graham v. John Deere Co., 383 U.S. 1, 17 (1966).
Discussing the question of obviousness of a patent that claims a
combination of known elements, the Court in KSR Int’l v. Teleflex, Inc., 127
S. Ct. 1727 (2007) explains:
When a work is available in one field of endeavor, design
incentives and other market forces can prompt variations of it,
either in the same field or a different one. If a person of
ordinary skill can implement a predictable variation, §103
likely bars its patentability. For the same reason, if 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

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its actual application is beyond his or her skill. Sakraida [v. AG
Pro, Inc., 425 U.S. 273 (1976)] and Anderson's-Black Rock[,
Inc. v. Pavement Salvage Co., 396 U.S. 57 (1969)] are
illustrative—a court must ask whether the improvement is more
than the predictable use of prior art elements according to their
established functions.
KSR, 127 S. Ct. at 1740. If the claimed subject matter cannot be fairly
characterized as involving the simple substitution of one known element for
another or the mere application of a known technique to a piece of prior art
ready for the improvement, a holding of obviousness can be based on a
showing that “there was an apparent reason to combine the known elements
in the fashion claimed.” Id., 127 S. Ct., at 1740-41. Such a showing
requires:
“some articulated reasoning with some rational underpinning
to support the legal conclusion of obviousness. . . . [H]owever,
the analysis need not seek out precise teachings directed to the
specific subject matter of the challenged claim, for a court can
take account of the inferences and creative steps that a person
of ordinary skill in the art would employ.” Id., 127 S. Ct. at
1741 (quoting In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)).

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).

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Claims 2, 4-6, 8, and 10
Regarding representative independent claim 4,2 Appellant argues that
Malaender does not teach or suggest selecting different constellations for
two or more of the active antennas as claimed. Appellant adds that Kadous
merely processes received symbol streams, but does not teach or suggest
varying the number of antennas or the constellations selected for the
antennas. According to Appellant, all of the antennas in Kadous use the
same constellation (App. Br. 11-12; Reply Br. 3).
The Examiner notes that Kadous discloses such constellation selection
since each antenna transmits an associated data stream whereby coded data
for each data stream is modulated based on one or more constellation
selections (Ans. 13-14).
The issue before us, then, is whether Appellant has shown that the
Examiner erred in finding that the collective teachings of Malaender and
Kadous teach or suggest all limitations of representative claim 4. For the
following reasons, we find that no such error has been shown.
Malaender discloses a multiple-input, multiple output (MIMO)
communication system 100 in which a transmitter 110 can adjust a
transmission parameter including the number of antennas to employ from an
array of antennas 111 (Malaender, Abstract, ¶¶ 0008, 0016, 0019; 0043-44;
Fig. 1A). The transmitter demultiplexes an input data stream 112 into
different substreams. Each substream is then transmitted from a different
transmit antenna (Malaender, ¶¶ 0019, 0024).

2 Appellant argues claims 2, 4-6, 8, and 10 together as a group. See App. Br.
11-12. Accordingly, we select claim 4 as representative. See 37 C.F.R.
§ 41.37(c)(1)(vii).
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Kadous discloses techniques for processing multiple received symbol
streams in a MIMO system in which the order that the symbol streams are
processed is based on metrics indicating the quality of the detected symbol
stream (Kadous, Abstract). The system comprises a transmitter system 110
that transmits a particular data stream over a respective transmit antenna.
Each data stream is independently processed (e.g., coded, interleaved, and
symbol mapped) at the transmitter (Kadous, col. 4, ll. 25-42; Fig. 1). The
multiplexed and coded data for each data stream is modulated (symbol
mapped) based on one or more modulation schemes (e.g., BPSK, QPSK, M-
PSK, or M-QAM) (Kadous, col. 4, ll. 48-52).
As shown in Figure 5, Kadous’ transmitter system comprises a
number of transmitters 122 that receive and process a respective
transmission symbol stream to generate a modulated signal for transmission
from the associated antenna 124 (Kadous, col. 18, ll. 15-17; Fig. 5).
Significantly, each data stream’s symbol mapping element 516 forms a non-
binary symbol and maps this symbol to a specific point in a signal
constellation corresponding to the selected modulation scheme (e.g., QPSK,
M-PSK, M-QAM, etc.) (Kadous, col. 17, ll. 45-51).
Based on this functionality, we find no error in the Examiner’s
conclusion that the collective teachings of Malaender and Kadous teach or
suggest all limitations of representative claim 4. We find that Kadous amply
suggests selecting different constellations for two or more of the active
antennas as claimed, and that such a teaching would have been readily
combinable with Malaender.
As an initial matter, the modulation and coding schemes of Kadous
noted above fully meet a “constellation” in light of Appellant’s description
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of the term in the Specification. See, e.g., Spec. ¶ 0037 (noting that
“constellations may be selected from, e.g., binary phase shift keying
(BPSK), quadrature phase shift keying (QPSK), 8-point phase shift keying
(8-PSK), 16-point quadrature amplitude modulation (16-QAM) and 64-
QAM.”); see also Spec. ¶ 0052.
Furthermore, each transmitted data stream in Kadous is independently
processed (i.e., separate coding and modulation on a per-antenna basis) to
provide a corresponding modulation symbol stream. Significantly, these
coding and modulation schemes for each data stream can be the same or
different (Kadous, col. 17, ll. 3-8; emphasis added).
As such, we find ample suggestion to provide different constellations
for transmission on two or more of the antennas that transmit the respective
data streams. Such a selection would have been well within the level of
ordinarily skilled artisans depending on the data stream transmitted by each
antenna.
We see no reason why such a teaching could not be applied to
Malaender’s system which transmits data streams via selected antennas from
an array. Since each substream in Malaender can be mapped to a particular
transmit antenna in the array (Malaender, ¶ 0024), and the number of
antennas employed is selected as noted above, skilled artisans would have
therefore selected different constellations for transmission on particular data
streams associated with respective selected antennas in view of Kadous’
teachings. That the transmitted constellation size can also be adjusted for
maximum throughput in Malaender (Malaender, ¶ 0025) only reinforces our
conclusion that skilled artisans could vary the constellations with respect to
the transmitted data streams in addition to the number of antennas.
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Appellant’s arguments pertaining to Kadous are unavailing. While
Kadous does process received symbol streams as Appellant indicates (App.
Br. 12; Reply Br. 3), this argument is not germane to the functionality of
Kadous’ transmission system of Figure 5—a system that transmits data
streams via an array of antennas and that varies the constellations on a per-
antenna basis as noted above.
We further find Appellant’s argument pertaining to the alleged use of
the same 16-QAM constellation in Kadous (App. Br. 12; Reply Br. 3)
unpersuasive. Although the performance shown in Figure 4 is for an MIMO
system with two transmit antennas and four receive antennas that uses 16-
QAM coding, the reference is by no means limited to this example. As we
noted above, Kadous strongly suggests varying the constellations for each
data stream (Kadous, col. 17, ll. 3-8).
We therefore find no error in the Examiner’s combining Kadous with
Malaender to arrive at the claimed invention. We add that ordinarily skilled
artisans would likewise have ample reason to select a subset of antennas
used in Kadous’ transmission system of Figure 5 in view of the teachings of
Malaender to, among other things, increase data throughput (Malaender,
Abstract, ¶ 0016). From either perspective, the limitations of representative
claim 4 are amply taught and suggested by the collective teachings of the
cited references.
For the foregoing reasons, Appellant has not persuaded us of error in
the Examiner’s rejection of representative claim 4. Therefore, we will
sustain the Examiner’s rejection of that claim, and claims 2, 5, 6, 8, and 10
which fall with claim 4.

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Independent Claims 15, 26, 37, and 48 and their Dependent Claims
Although Appellant nominally argues the rejection of independent
claims 15, 26, 37, and 48 and their dependent claims separately (App. Br.
14-18; Reply Br. 5-8), Appellant essentially reiterates the same arguments
we considered above with respect to claim 4. Therefore, we sustain the
rejection of independent claims 15, 26, 37, and 48 and dependent claims 13,
16, 17, 19, 21, 24, 27, 28, 30, 32, 35, 38, 39, 41, 43, 46, 49, 50, 52, and 54
for the same reasons discussed above with respect to claim 4.

Claim 7
Regarding claim 7, Appellant argues that the prior art does not teach
or suggest selecting an optimum number of antennas to maximize a
minimum signal-to-noise ratio (SNR) margin as claimed (App. Br. 13-14;
Reply Br. 4-5). The Examiner contends that Kadous teaches the limitation
since symbol streams are selected with the highest margin and that each
symbol stream is based on SNR (Ans. 14).
The issue before us, then, is whether Appellant has shown that the
Examiner erred in finding that the prior art teaches or suggests selecting an
optimum number of antennas to maximize a minimum SNR margin as
claimed. For the following reasons, we find that Appellant has shown such
error.
We note at the outset that claim 7 does not merely call for selecting an
optimum number of antennas based on an SNR margin, but rather such
selection is to maximize a minimum SNR ratio margin. To interpret this
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limitation, we first turn to Appellant’s Specification for guidance.3 The
Specification notes that the minimum SNR margin is given by Equation (2),
and is based, in part, on the minimum post-processing SNR among all data
substreams (Spec. ¶¶ 0021-0024). It is this minimum SNR margin that is
maximized via antenna selection—a selection yielded via Equations (5) and
(6) (Spec. ¶¶ 0030-35).
With this guidance, we turn to the prior art. Although Kadous selects
a detected symbol with the highest SNR margin (i.e., the difference between
the equivalent SNR and the required SNR) for recovery as the Examiner
indicates (Kadous, col. 16, ll. 15-33), we agree with Appellant that this
teaching does not suggest selecting an optimum number of antennas based
on such a margin. And even if it did, we still fail to see how such a selection
would maximize a minimum SNR margin as claimed in light of the
Specification.
Malaender fares no better in this regard. While Malaender does teach
selecting an optimum number of antennas as noted previously, this selection
is based on factors that, at best, merely account for the SNR (see, e.g.,
Malaender, ¶¶ 0043-51). This selection, however, is not based on an SNR
margin, let alone maximizing a minimum SNR margin as claimed in light of
the Specification.

3 See Phillips v. AWH Corp., 415 F.3d 1303, 1321 (Fed. Cir. 2005) (en banc)
(“[T]he specification is the single best guide to the meaning of a disputed
term, and…acts as a dictionary when it expressly defines terms in the claims
or when it defines them by implication.”) (internal quotation marks and
citations omitted).
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For the foregoing reasons, Appellant has persuaded us of error in the
Examiner’s rejection of independent claim 7. Therefore, we will not sustain
the Examiner’s rejection of that claim.

Claims 18, 29, 40, 51, and 57
Since claims 18, 29, 40, 51, and 57 recite limitations commensurate
with claim 7, we will not sustain the Examiner’s rejection of these claims for
the same reasons we indicated above with respect to claim 7.

DECISION
We have sustained the Examiner's rejection with respect to claims 2,
4-6, 8, 10, 13, 15-17, 19, 21, 24, 26-28, 30, 32, 35, 37-39, 41, 43, 46, 48-50,
52, and 54. We have not, however, sustained the Examiner's rejection with
respect to claims 7, 18, 29, 40, 51, and 57. Therefore, the Examiner’s
decision rejecting claims 2, 4-8, 10, 13, 15-19, 21, 24, 26-30, 32, 35, 37-41,
43, 46, 48-52, 54, and 57 is affirmed-in-part.
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-IN-PART

KIS

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