Ex Parte Hassan

Board of Patent Appeals and Interferences

Aug 26, 2002

08669937 (B.P.A.I. Aug. 26, 2002)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.
Paper No. 28
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte AMER A. HASSAN
_____________
Appeal No. 2000-1900
Application No. 08/669,937
______________
ON BRIEF
_______________
Before RUGGIERO, DIXON, and GROSS, Administrative Patent Judges.
RUGGIERO, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on the appeal from the final rejection of
claims 1, 3, 4, 7, 9-12, and 14-21. Claim 8 has been canceled
and claims 2, 5, 6, and 13 have been indicated to be allowable
subject to being rewritten in independent form to include all of
the limitations of the base claim and any intervening claims.
The claimed invention relates to a method and apparatus for
decoding digitally encoded communication signals transmitted over
a fading channel. More particularly, a sequence of test bits are
Appeal No. 2000-1900
Application No. 08/669,937
2
transmitted in each time slot in a coded time-division multiple
access (TDMA) communication system, and a mathematical distance
between the transmitted known test bits and the corresponding
received bits is determined by the receiver to indicate whether
the corresponding time slot is reliable. Alternatively, a
concatenated coding scheme can be used to transmit digital
communication signals, and reliability information can be
generated by using an inner code and the output of an inner
decoder.
Claims 1 and 7 are illustrative of the invention and read as
follows:
1. A method for generating reliability information
indicative of the reliability of data transmitted over a
TDMA communication channel, comprising the steps of:
transmitting one or more of a sequence of test bits in
each time slot of the TDMA communication channel, the test
bits being known to the receiver prior to the step of
transmitting;
determining, at the receiver, a mathematical distance
between the sequence of test bits as known to the receiver
and the sequence of test bits as received by the receiver;
and
generating, at the receiver, reliability information
indicative of the reliability of data transmitted over the
TDMA communication channel based on the mathematical
distance, and information estimates of the transmitted data.
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7. A method for transmitting, comprising the steps of:
performing a first coding of bits to be transmitted,
using a first code, to generate first coded bits;
performing a second coding of the first coded bits,
using a second code, to generate second coded bits;
transmitting the second coded bits over a TDMA
communication channel to a receiver;
receiving the second coded bits at the receiver as one
or more possibly corrupted codewords; and
decoding the second coded bits by correcting, in a
first decoder, corrupted codewords within a threshold
mathematical distance or generating, in the first decoder,
erasures for all corrupted codewords not within the
threshold mathematical distance; and
correcting, in a second decoder, errors and erasures
generated by the first decoder.
The Examiner relies on the following prior art:
Saleh et al. (Saleh) 5,048,057 Sep. 10, 1991
Wei 5,088,113 Feb. 11, 1992
McConnell 5,206,864 Apr. 27, 1993
Boyd et al. (Boyd), “A Concatenated Coding Approach for High Data
Rate Applications,” NTC ‘77 Conference Record, Vol. 3, pp.36:2-1
to 36:2-7 (1977).
Hassan et al. (Hassan), “On Decoding Concatenated Codes,” 36 IEEE
Transactions on Information Theory, No. 3, pp. 677-83 (May 1990).
Claims 1, 3, 4, 12, and 14-16 stand finally rejected under
35 U.S.C. § 103(a) as being unpatentable over Wei in view of
Saleh. Claims 7, 9-11, and 17-21 stand finally rejected under
35 U.S.C. § 103(a) as being unpatentable over Hassan in view of
Appeal No. 2000-1900
Application No. 08/669,937
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Boyd. In a separate rejection under 35 U.S.C. § 103(a), claims
7, 9, 11, 17, 19, and 21 also stand finally rejected as being
unpatentable over McConnell in view of Boyd.
Rather than reiterate the arguments of Appellant and the
Examiner, reference is made to the Brief (Paper No. 17) and
Answer (Paper No. 18) for their respective details.
OPINION
We have carefully considered the subject matter on appeal,
the rejections advanced by the Examiner, the arguments in support
of the rejections and the evidence of obviousness relied upon by
the Examiner as support for the rejections. We have, likewise,
reviewed and taken into consideration, in reaching our decision,
Appellant’s arguments set forth in the Brief along with the
Examiner’s rationale in support of the rejections and arguments
in rebuttal set forth in the Examiner’s Answer.
It is our view, after consideration of the record before us,
that the evidence relied upon and the level of skill in the
particular art would have suggested to one of ordinary skill in
the art the obviousness of the invention as set forth in claims
1, 3, 4, 7, 9-12, and 14-21. Accordingly, we affirm.
Appeal No. 2000-1900
Application No. 08/669,937
1 The Answer makes reference to the statement of the rejection appearing
at pages 2 and 3 of the final Office action mailed March 29, 1999 (Paper No.
12).
5
Appellant’s arguments in response to the Examiner’s
rejection of the appealed claims are organized according to a
suggested grouping of claims indicated at page 5 of the Brief.
We will consider the appealed claims separately only to the
extent separate arguments for patentability are presented. Any
dependent claim not separately argued will stand or fall with its
base claim. Note In re King, 801 F.2d 1324, 1325, 231 USPQ 136,
137 (Fed. Cir. 1986); In re Sernaker, 702 F.2d 989, 991, 217 USPQ
1, 3 (Fed. Cir. 1983).
We consider first the Examiner’s 35 U.S.C. § 103(a)
rejection of claims 1, 3, and 4 as being unpatentable over Wei in
view of Saleh. After reviewing the Examiner’s analysis (Answer,
pages 3 and 4)1, it is our view that such analysis carefully
points out the teachings of the Wei and Saleh references,
reasonably indicates the perceived differences between this prior
art and the claimed invention, and provides reasons as to how and
why the prior art teachings would have been modified and/or
combined to arrive at the claimed invention. In our opinion, the
Examiner's analysis is sufficiently reasonable that we find that
the Examiner has at least satisfied the burden of presenting a
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Application No. 08/669,937
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prima facie case of obviousness. The burden is, therefore, upon
Appellant to come forward with evidence and/or arguments which
persuasively rebut the Examiner’s prima facie case of
obviousness. Only those arguments actually made by Appellant
have been considered in this decision. Arguments which Appellant
could have made but chose not to make in the Brief have not been
considered (see 37 CFR § 1.192(a)).
In response, Appellant contends (Brief, pages 7-9) that the
Examiner has not established a prima facie case of obviousness
since the proposed combination of Wei and Saleh does not teach or
suggest all of the limitations of appealed independent claim 1,
the representative claim for Appellant’s first suggested grouping
(including claims 1, 3, and 4). Initially, Appellant argues
(id., at page 8) that, in contrast to the language of claim 1,
the Wei and Saleh references are not directed to TDMA
communication systems. Further, Appellant asserts, pointing to
language at column 4, lines 54-68 in Wei and column 5, lines 24-
35 in Saleh, that “ . . . both Wei and Saleh disclose “hard”
decision features and do not disclose or suggest soft decision
features as claimed . . . . ” (Id., Appellant’s emphasis).
After careful review of the applied Wei and Saleh references
in light of the arguments of record, we are in general agreement
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Application No. 08/669,937
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with the Examiner’s position as stated in the Answer. At the
outset, we note that we find Appellant’s assertions to be
unpersuasive with respect to the alleged lack of disclosure of
TDMA communication systems in the applied prior art. Our review
of the disclosure of Saleh reveals a clear indication of the
applicability of the described frequency hopping technique to
TDMA communication systems.
We further are in agreement with the Examiner with respect
to the interpretation of the “hard” decision operations disclosed
by both Wei and Saleh as related to the language of
representative claim 1. In our view, Appellant’s arguments
(Brief, page 9) merely repeat the critical language of claim 1,
i.e., “determining, . . . , a mathematical distance between the
sequence of test bits as known to the receiver and the sequence
of test bits as received by the receiver,” and draw the
unsupported conclusion that Wei and Saleh do not teach or suggest
such a claimed limitation. As such, we do not find such
arguments to be convincing of any error in the Examiner’s
position.
The “hard” decision operation performed on the interference
signal points disclosed at column 4, lines 6-14 of Wei is
contrasted with “soft” decisions in the sense that signal points
Appeal No. 2000-1900
Application No. 08/669,937
2 Saleh has a similar disclosure at column 5, lines 18-43 and column 10,
lines 63-68.
3 See discussion of “Hamming distance” or “signal distance” at page 131
of Weik’s Standard Dictionary of Computers and Information Processing, (2nd
Ed., Hayden Book Co., Inc., Rochelle Park, NJ (1977)), a copy of which is
enclosed with this decision.
8
are examined in isolation rather than including a consideration
of plural signal points. In describing the “hard” decision
operation, Wei discloses (column 4, lines 57-67) the comparison
of received signal points with the known transmitted points and
the resultant determination of the number of errors in each
sequence pattern.2 We agree with the Examiner that, despite the
fact that signal points are examined in isolation, the skilled
artisan would recognize this “hard” decision decoding as
involving a determination of a “mathematical distance” of the
received bit sequence pattern with a known bit sequence pattern
in relation to a threshold distance such as a Hamming distance.3
In this regard, we also point out that Appellant’s own
specification (page 6, lines 7-10) recognizes that in
conventional hard decision decoders, a mathematical distance
determination is made using a minimum Hamming distance threshold.
Given this evidence before us, our review of the language of
claim 1 reveals nothing which would require a “soft” decision
operation, as asserted by Appellant, or, for that matter, any
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Application No. 08/669,937
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language which would distinguish over the “hard” decision
operation disclosed by Wei and Saleh. In our view, to whatever
extent Appellant’s disclosed “soft” decision decoding
distinguishes over the “hard” decision decoding of the prior art,
such distinctions do not appear in the claims. As such,
Appellant’s arguments improperly attempt to narrow the scope of
the claim by implicitly adding disclosed limitations which have
no basis in the claim. See In re Morris, 127 F.3d 1048, 1054-55,
44 USPQ2d 1023, 1027-28 (Fed. Cir. 1997).
In view of the above discussion and the totality of the
evidence on the record, it is our opinion that the Examiner has
established a prima facie case of obviousness which has not been
rebutted by any convincing arguments from Appellant.
Accordingly, the Examiner’s 35 U.S.C. § 103(a) rejection of
representative independent claims 1, as well as dependent claims
3 and 4 which fall with claim 1, is sustained.
Turning to a consideration of the Examiner’s obviousness
rejection of independent claim 12, the representative claim for
Appellant’s suggested grouping (including claims 12 and 14-16),
we sustain this rejection as well. Representative claim 12 is a
system counterpart to previously discussed method claim 1. In
asserting the patentability of claim 12, Appellant reiterates the
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Application No. 08/669,937
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arguments which assert the alleged distinction between his “soft”
decision decoding and the “hard” decision decoding of the applied
prior art. We find such arguments to be unpersuasive for all of
the reasons discussed supra.
We next consider the Examiner’s 35 U.S.C. § 103(a)
rejections of independent claim 7, the representative claim for
Appellant’s suggested grouping (including claims 7 and 9-11), and
independent claim 17, the representative claim for the group
including claims 17-21, based on the combination of McConnell in
view of Boyd or, in the alternative, Hassan in view of Boyd. We
sustain these rejections as well. In response to the rejection,
Appellant initially contends (Brief, page 16) that McConnell
lacks a teaching or suggestion of application of concatenated
coding schemes to TDMA channels. Further Appellant asserts (id.)
that, unlike the present claimed invention, McConnell “ . . .
performs a second coding of the first coded bits and the original
data to generate second coded bits.” In addition, McConnell is
attacked by Appellant as failing to teach the use of a threshold
mathematical distance in performing soft decisions, while Boyd is
asserted as lacking a disclosure of the correction of erasures as
claimed. (Id.)
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After careful review of the McConnell and Boyd references,
we find none of Appellant’s arguments to be persuasive. In our
view, Appellant’s arguments focus on the individual differences
between the limitations of representative claims 7 and 17 and
each of the applied references. It is apparent, however, from
the Examiner’s line of reasoning in the Answer, that the basis
for the obviousness rejection is the combination of McConnell and
Boyd. One cannot show nonobviousness by attacking references
individually where the rejections are based on combinations of
references. In re Keller, 642 F.2d 413, 425, 208 USPQ 871,
881 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 1097, 231 USPQ
375, 380 (Fed. Cir. 1986).
In other words, while Appellant contends that McConnell
lacks a teaching of a TDMA channel application, the suggestion to
apply concatenated coding schemes to TDMA systems is clearly
provided by Boyd. Further, although Appellant argues that Boyd
has no disclosure of the correction of erasures, this feature is
clearly taught by McConnell in which, as disclosed at column 5,
lines 40-60, erasures for a block of symbols are marked or
generated at the first (inner or Hamming) decoder, and corrected
at the second (outer or Reed-Solomon) decoder.
Appeal No. 2000-1900
Application No. 08/669,937
4 We also observe that, while it is our opinion that the language of
appealed claims 7 and 17 does not require the use of “soft” decision decoding,
the concatenated coding scheme of Boyd discloses the use of “soft” decisions
at the inner decoder (Boyd, page 36:2-2, left column).
12
Further, in our view, regardless of the merits of
Appellant’s argument that, in contrast to their invention,
McConnell performs a second coding of the first coded bits and
the original data, we find no claim language that precludes a
second encoding of original data. As to Appellant’s contention
that McConnell does not disclose the use of a threshold
mathematical distance in determining errors, we refer to our
earlier discussion where we found that a skilled artisan would
appreciate and recognize that “hard” decision decoding, such as
involved in the Hamming decoder of McConnell, would involve a
consideration of a “threshold mathematical distance” as claimed.4
With regard to the Examiner’s alternative obviousness
rejection based on the combination of Hassan and Boyd, we note
that Appellant, with respect to Hassan, has reiterated the
arguments previously made against McConnell. For all of the
reasons discussed supra, we find such arguments to be
unpersuasive.
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In summary, we have sustained the 35 U.S.C. § 103(a)
rejection of all of the claims on appeal. Therefore, the
decision of the Examiner rejecting claims 1, 3, 4, 7, 9-12, and
14-21 is affirmed.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED

JOSEPH F. RUGGIERO )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOSEPH L. DIXON ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
ANITA PELLMAN GROSS )
Administrative Patent Judge )
JFR:hh
Appeal No. 2000-1900
Application No. 08/669,937
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