Ex Parte Xu et al

Patent Trial and Appeal Board

Feb 23, 2016

11526122 (P.T.A.B. Feb. 23, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
111526,122 0912512006 YuhuanXu
100809 7590 02/25/2016
Core Wireless Licensing Ltd
5601 Granite Parkway
Suite 1300
Plano, TX 75024
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
54073-POOSUS 1151
EXAMINER
SANDIFER, MATTHEW D
ART UNIT PAPER NUMBER
2183
NOTIFICATION DATE DELIVERY MODE
02/25/2016 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
ipadmin-core@core-wireless.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte YUHUAN XU and LUDWIG SCHWOERER
Appeal2014-004825
Application 11/526, 122
Technology Center 2100
Before CARL W. WHITEHEAD, JR, MICHAEL J. STRAUSS, and
AARON W. MOORE, Administrative Patent Judges.
MOORE, Administrative Patent Judge.
DECISION ON APPEAL
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Application 11/526, 122
STATEMENT OF THE CASE
Appellants 1 appeal under 35 U.S.C. § 134(a) from the Final Rejection
of claims 1, 3, 5, 8, 9, 11, 13, and 16, which constitute all of the claims now
pending in the application. We have jurisdiction under 35 U.S.C. § 6(b ).
We affirm.
THE INVENTION
The application is directed to "a method and apparatus for
implementing a discrete Fourier transformation (DPT) of a predetermined
vector size." (Abstract.) Claim 1, reproduced below, is illustrative of the
claimed subject matter:
1. A method, comprising:
performing, at a first discrete Fourier transformation (DPT)
module implemented in hardware, a first transformation com-
prising a first predetermined number of first discrete Fourier
transformations of a first vector size, wherein the performing
the first transformation comprises summing a number of prod-
ucts of the first vector size, each product calculated by multi-
plying each input vector of the first vector size by at least one
twiddle factor provided by at least one first twiddle factor gen-
erating unit;
performing, at a second DPT module implemented in hard-
ware, a subsequent second transformation comprising a second
predetermined number of second discrete Fourier transfor-
mations of a second vector size, wherein the first predetermined
number corresponds to the second vector size and the second
predetermined number corresponds to the first vector size, and
wherein the performing the subsequent second transformation
comprises summing a number of products of the second vector
1 Appellants identify Core Wireless Licensing S.A.R.L. as the real party in
interest. (See App. Br. 3.)
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Application 11/526, 122
size, each product calculated by multiplying each input vector
of the second vector size by a second twiddle factor generating
unit;
wherein the first transformation further comprises an implementa-
tion of a recursive stage of a length n such that:
when a DPT length is less than the stage length n, the re-
cursive stage is bypassed through a selective bypass unit;
and
when the DPT length is not less than the stage length n,
the first n/2 incoming samples are stored in a First-in-First-
Out memory, and a butterfly operation of the bypass unit is
performed on the stored first n/2 incoming samples together
with the next n/2 incoming samples to produce the results
that are multiplied by the at least one twiddle factor.
REFERENCES
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
P. Duhamel and ~vf. Vetterli, Fast Fourier Transforms: A Tutorial
Review and a State of the Art, in Digital Signal Processing Handbook,
(V. Madisetti & D. Williams ed., 1999)
Y.-T. Lin, P.-Y. Tsai, and T.-D. Chiueh, Low-Power Variable-Length
Fast Fourier Transform Processor, IEE Proceedings on Computers
and Digital Techniques, Vol. 152, No. 4, 499-506 (July 2005)
THE REJECTIONS
Claims 1, 3, 5, 8, 9, 11, 13, and 16 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Duhamel and Lin. (See Final Act. 2.)
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Application 11/526, 122
APPELLANTS' CONTENTIONS
Appellants argue that the rejections were improper because the cited
combination fails to disclose the following features of claim 1:
when a DPT length is less than the stage length n, the recursive
stage is bypassed through a selective bypass unit; and
when the DPT length is not less than the stage length n, the first
n/2 incoming samples are stored in a First-in-First-Out memory,
and a butterfly operation of the bypass unit is performed on the
stored first n/2 incoming samples together with the next n/2 in-
coming samples to produce the results that are multiplied by the
at least one twiddle factor.
(See App. Br. 7.)
ANALYSIS
The Examiner provided the following explanation of how the subject
limitations are met in Lin:
A first recursive stage is of length 2048 (see Lin, Figure 5,
wherein n=2048 and n/2= l 024 samples may be stored in
SRAMl ). Lin explicitly discloses bypassing the first stage via
"MUX l" when a length of the total DPT to be performed is less
than 2048 (see Section 2.3 and Figure 5). Furthermore, the first
stage is not bypassed via MUX 1 when the total DPT length is
2048 (see Section 2.3), in which case n/2=1024 samples are
stored in the SRAMl of Figure 5 which is a first-in-first-out
memory, and a butterfly operation is performed by the radix-2
PE "Ul" on the stored first n/2 incoming samples together with
the next n/2 incoming samples to produce the results that are
multiplied by twiddle factors of ROM 1. Therefore, Lin explic-
itly discloses the limitation in question, as recited in the inde-
pendent claims.
More specifically, the Examiner agrees with Appellant's de-
scription that Lin's "variable-length FFT processor can perform
FFT operations of three different lengths: 2048, 1024 and 512
points. Lin discloses that if a 512-point FFT is executed, input
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Application 11/526, 122
signals skip the first two stages through the control of the mul-
tiplexer MUX 2. If a 1024-point FFT is performed, the first stage
is bypassed through the multiplexer MUX 1." (See Appeal Brief,
page 8.)
The reason for the bypassing of stages in Lin's architecture is
because each stage stores-and performs a butterfly operation on-
a different respective amount of samples. See Lin, Figure 5,
which shows Lin's architecture comprising a series of recursive
stages of successively decreasing storage amounts, wherein the
first stage stores 1024 samples for performing a butterfly opera-
tion on 2048 total samples, the second stage stores 512 samples
for performing a butterfly operation on 1024 total samples, etc.
This is supported at least by Figure 2 and Section 2.1 of Lin,
wherein a first stage stores 4 samples for an N=8-point FFT, such
that the butterfly units work at 50% utilization since half the time
they are bypassed, i.e. during the time the input sequence is
divided into two parallel data streams by storing the first 4
samples of an N=8 point data stream.
Thus, for a 512-point FFT which comprises performing a first
butterfly operation on 512 total samples, the first two stages are
bypassed since they each perform a butterfly on more than 512
samples and the third stage performs a butterfly on exactly 512
samples. Similarly, for a 1024-point FFT which comprises per-
forming a first butterfly operation on 1024 total samples, the first
stage is bypassed since it performs a butterfly on 2048 samples,
i.e. on more samples than are provided. For a 2048-point FFT,
the first stage is utilized since it is necessary for performing the
first butterfly stage on the full 2048 samples that are provided.
Therefore, Lin discloses a series of stages, each performing a
butterfly operation on a respective different number of samples.
Thus, each stage comprises a "stage length" equal to the number
of samples that it operates upon, and equal to twice its storage
amount. In this respect, the stages disclosed by Lin teach "the
first n/2 incoming samples are stored in a First-In-First-Out
memory, and a butterfly operation is performed on the stored first
n/2 incoming samples together with the next n/2 incoming
samples" as claimed. And by teaching selectively bypassing a
first stage that performs a butterfly operation on 2048 samples
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Application 11/526, 122
via MUX 1 when the FFT length is 1024-point or 512-point, Lin
discloses selectively bypassing a stage of length 2048 when the
FFT length is less than 2048, i.e. Lin discloses "when a DPT
length is less than the stage length n, the recursive stage is by-
passed through a selective bypass unit" as claimed. Finally, since
the first stage of length 2048 and which stores 1024 samples is
utilized when the FFT length is 2048-point, Lin discloses "when
the DPT length is not less than the stage length n, the first n/2
incoming samples are stored in a First-In-First-Out memory, and
a butterfly operation of the bypass unit is performed on the stored
first n/2 incoming samples together with the next n/2 incoming
samples" as required by independent claim 1.
(Ans. 7-9.)
In response to this detailed analysis of how the limitations read on
Lin, Appellants (after generally agreeing with the Examiner's description of
how Lin operates) simply assert that the claim language is not met:
Appellants respectfully submit that Lin only discloses perform-
ing FFT operations of three different lengths: 2048, 1024 and
512 points. In Lin, if 512-point FFT is executed, input signals
skip the first two stages through the control of the multiplexer
MUX 2 and if a 1024-point FFT is performed, the first stage is
bypassed through the multiplexer MUX 1. There is no sugges-
tion or hint in the text or Figure 5 of Lin that "when a DPT length
is less than the stage length n, the recursive stage is bypassed
through a selective bypass unit ... and when the DPT length is
not less than the stage length n, the first n/2 incoming samples
are stored in a First-in-First-Out memory, and a butterfly
operation of the bypass unit is performed on the stored first n/2
incoming samples together with the next n/2 incoming samples"
as required by independent claim 1.
(Reply Br. 3--4.)
We agree with and adopt the factual findings of the Examiner and the
conclusion of obviousness. In particular, we agree that Lin teaches "a
recursive stage of a length n" (the first stage of Fig. 5, with a "stage length"
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Application 11/526, 122
of 2048), which is bypassed "when [the] DFT length is less than the stage
length" (i.e., when the DPT length is 512 or 1024, both being less than
2048), and, "when the DPT length is not less than the stage length" (i.e.,
when the DPT length is 2048, which is not less than 2048), the first n/2
samples are stored in a First-in-First-Out memory (SRAMl, which is 1024
in size) and a butterfly operation is performed (in Ul) on the first and second
n/2 samples to produce results that are multiplied by twiddle factors stored
in ROMI.
Given the Examiner's thorough findings, Appellants' bare recitation
of the claim language, lacking persuasive evidence or technical reasoning
explaining why the prior art is wanting, is insufficient to overcome the prima
facie case of obviousness. See 37 C.F.R. § 41.37(c)(l)(vii) ("A statement
which merely points out what a claim recites will not be considered an
argument for separate patentability of the claim."); In re Lovin, 652 F.3d
1349, 1356 (Fed. Cir. 2011) ("[W]e hold that the Board reasonably
interpreted Rule 41.37 to require more substantive arguments in an appeal
brief than a mere recitation of the claim elements and a naked assertion that
the corresponding elements were not found in the prior art."); see also Ex
Parte Belinne, No. 2009-004693, 2009 WL 2477843, at *4 (BPAI 2009)
(informative) (affirming the rejection where "Appellants [did] not present
any arguments to explain why the Examiner's explicit fact finding is in
error").
To the extent Appellants argue that the claims require performing FFT
operations of lengths other than 2048, 1024, and 512 points (see App. Br. 9),
such argument is unpersuasive because it is not commensurate in scope with
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Application 11/526, 122
claim 1. See Jn re Hiniker Co., 150 F.3d 1362, 1369 (Fed. Cir. 1998)
("[T]he name of the game is the claim.")
For the reasons discussed above, we sustain the rejection of
independent claim 1under35 U.S.C. § 103(a) over Duhamel and Lin and,
on the same basis, we sustain the rejection of independent claims 8, 9, and
16, as well as the rejection of dependent claims 3, 5, 11, and 13 which are
not separately argued.
DECISION
The rejection of claims 1, 3, 5, 8, 9, 11, 13, and 16 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)(l )(iv).
AFFIRMED
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