Ex Parte Liu et al

Patent Trial and Appeal Board

Dec 21, 2016

13417235 (P.T.A.B. Dec. 21, 2016)

United States Patent and Trademark Office
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
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
MDT-075 7125
EXAMINER
SLOMS, NICHOLAS
ART UNIT PAPER NUMBER
2476
MAIL DATE DELIVERY MODE
13/417,235 03/10/2012
96758 7590
Law Office of Zheng Jin
P.O.Box 731450
San Jose, CA 95173
12/21/2016
Jianhan Liu
12/21/2016 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JIANHAN LIU, JAMES WANG,
HUANCHUN YE, and YUNGPING HSU
Appeal 2016-004255
Application 13/417,23 51
Technology Center 2400
Before JASON V. MORGAN, HUNG H. BUI, and SHARON FENICK,
Administrative Patent Judges.
BUI, Administrative Patent Judge.
DECISION ON APPEAL
Appellants seek our review under 35 U.S.C. § 134(a) of the
Examiner’s Final Office Action rejecting claims 1—20, which are all of the
claims pending on appeal. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.2
1 According to Appellants, the real party in interest is MediaTek Singapore
Pte. Ltd. App. Br. 1.
2 Our Decision refers to Appellants’ Appeal Brief filed August 18, 2015
(“App. Br.”); Reply Brief filed March 8, 2016 (“Reply Br.”); Examiner’s
Answer mailed January 8, 2016 (“Ans.”); Final Office Action mailed May
18, 2015 (“Final Act.”); and original Specification filed March 10, 2012
(“Spec.”).
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Application 13/417,235
STATEMENT OF THE CASE
Link adaptation is commonly used by wireless stations (e.g., mobile
terminals) to adapt the modulation and coding scheme (MCS) used
according to the quality of a radio channel (e.g., time-varying channel
conditions) in wireless communication systems including, for example, an
access point (AP) and multiple wireless stations (e.g., mobile devices).
Spec. 120.
“For example, in the case of good channel condition, a larger
modulation scheme or higher code rate is used by the transmitter
to increase the data rate. On the other hand, in the case of poor
channel condition, a smaller modulation scheme or lower code
rate is used by the transmitter to decrease the data rate.”
Spec. 120.
In order to exploit the channel knowledge, i.e., channel station
information (CSI) for link adaptation, [1] a wireless station must first send a
request to an AP, and [2] the AP must send a response (e.g., CSI including,
for example, a transmit power and link margin) back to the wireless station.
Id. 123. “Based on the feedback, [3] the [wireless] station is then able to
obtain the channel condition and [then] apply link adaptation.” Id. This
process is known as a “closed-loop” link adaptation scheme because the
wireless station and the AP must hand-shake and share the channel station
information (CSI), with the drawback that the hand-shaking requires too
much time and incurs extra overhead. Id.
As a solution, Appellants propose “an open-loop fast link adaptation
scheme [] to improve efficiency and to save power” in which wireless
station 202, as shown in Figure 2, is configured: (1) to receive a downlink
packet in the form of a beacon or polling packet [periodically] transmitted
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from AP 201 that contains what Appellants characterize as “open-loop link
metric” (OLM) including “[i] a transmit power and [ii] a receiver sensitivity
of the AP,” and based on receipt of the downlink packet, (2) to measure a
signal strength of the downlink packet, and (3) to apply link adaptation, i.e.,
determine the appropriate modulating and coding scheme (MCS). Spec.
124.
Appellants’ Figure 2 is reproduced below with additional markings
for illustration.
Appellants’ Figure 2 shows wireless communication system 200
including AP 201 and wireless station 202 applying
open-loop fast link adaptation.
As shown in Figure 2, AP 201 transmits a “downlink” singal
including an “open-loop” link metric (OLM) while wireless station 202
measures signal strength, determines modulation and coding (MCS) based
on the OLM, and transmits the “uplink” signal using the MCS.
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Claims 1,8, and 15 are independent. Claim 1 is illustrative of
Appellants’ invention, shown in Figure 2, as reproduced with disputed
limitations emphasized:
1. A method comprising:
receiving a downlink packet by a station in an orthogonal
frequency division multiplexing (OFDM) system,
[ 1 ] wherein the downlink packet comprises an
open-loop link metric value from an access point,
[2] wherein the station receives the open-loop
link metric value from the access point without sending a
preceding request to the access point, and
[3] wherein the open-loop link metric value is
indicative of a transmit power of the downlink packet and a
receiver sensitivity of the access point;
measuring a signal strength of the downlink packet and
determining a received signal strength indication (RSSI) value;
and
applying open-loop link adaptation and thereby
determining a modulation and coding scheme (MCS) level
based on the open-loop link metric value and the RSSI value.
App. Br. 21 (Claims App’x.).
Evidence Considered
Sadri US 2005/0032514 A1 Feb. 10, 2005
Wentink US 2005/0030976 A1 Feb. 10, 2005
Yao US 2007/0268859 A1 Nov. 22, 2007
VanLaningham US 7,403,780 B2 July 22, 2008
Biswas US 2008/0304427 A1 Dec. 11,2008
Soliman US 2008/0310485 A1 Dec. 18, 2008
Zhang US 2011/0039568 A1 Feb. 17,2011
Examiner’s Rejections and References
(1) Claims 1,8, and 15 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Sadri and Yao. Final Act. 6—7.
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Application 13/417,235
(2) Claims 2, 9, and 18 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Sadri, Yao, and Soliman. Final Act. 7.
(3) Claims 3, 10, and 16 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Sadri, Yao, and Biswas. Final Act. 8.
(4) Claims 4, 5, 11, 12, and 17 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Sadri, Yao, and Zhang. Final Act. 8—9.
(5) Claims 6, 13, and 19 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Sadri, Yao, and Wentink. Final Act. 9.
(6) Claims 7, 14, and 20 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Sadri, Yao, and VanLaningham. Final Act. 10.
ISSUE
Based on Appellants’ arguments, the dispositive issue presented on
appeal is whether the Examiner erred in finding the combination of prior art
references teaches or suggests the disputed limitations: (1) “wherein the
station receives the open-loop link metric value from the access point
without sending a preceding request to the access point” and (2) “wherein
the open-loop link metric value is indicative of a transmit power of the
downlink packet and a receiver sensitivity of the access point,” as recited in
each of Appellants’ independent claims 1, 8, and 15. App. Br. 6—12; Reply
Br. 4-10.
ANALYSIS
Claim 1 recites Appellants’ method at a [wireless station in an
orthogonal frequency multiplexing (OFDM) system] comprising several
steps: (1) “receiving a downlink packet”; (2) “measuring a signal strength of
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Application 13/417,235
the downlink packet and determining a received signal strength indication
(RSSI) value;” and then (3) “applying open-loop link adaptation and thereby
determining a modulation and coding scheme (MCS) level based on the
open-loop link metric value and the RSSI value,”
[ 1 ] wherein the downlink packet comprises an open-
loop link metric value from an access point,
[2] wherein the station receives the open-loop link
metric value from the access point without sending a preceding
request to the access point, and
[3] wherein the open-loop link metric value is
indicative of [i] a transmit power of the downlink packet and
[ii] a receiver sensitivity of the access point.
As recited in Appellants’ claim 1, the term “open-loop” used in
connection with the “metric value” or “link adaptation” refers to an “open-
loop” link adaptation scheme in which a wireless station is required to first
receive a downlink packet from an access point (AP) without sending a
preceding request to the AP. Spec. Tflf 24, 29.
In support of the rejection of independent claims 1, 8, and 15, the
Examiner finds Sadri teaches Appellants’ claimed method [shown in Figure
1] including most of the limitations, except for an express disclosure of the
“open-loop metric” containing “a receiver sensitivity of the access point,” as
taught by Yao. Final Act. 6—7 (citing Sadri || 3, 16, 19-20, 25—26, 38, Fig.
1; Yao 142; see also | 52).
Sadri’s Figure 1 shows Appellants’ claimed method in the context of
an orthogonal frequency multiplexing (OFDM) system including an access
point (AP) and a wireless station, as reproduced below with additional
markings for illustration.
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1
Device
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Sadri’s Figure 1 shows a wireless communication orthogonal
frequency multiplexing (OFDM) system including devices (e.g., AP and
wireless stations) 102, 104 establishing orthogonal frequency multiplexing
(OFDM) communication channels (e.g., channel 106) and exchanging
channel state information (CSI), via channel 106.
According to Sadri, devices (e.g., AP and wireless stations) 102, 104
are equipped with subcarrier management agents (SMA) 112, 114 to
perform adaptive control of channel-related parameters in response to
received channel state information (CSI) in two different modes: (1) closed-
loop mode, or (2) open-loop mode. Sadri || 17—20. Channel state
information (CSI) may include channel-related parameters such as received
signal strength indicator (RSSI), coding type, and modulation type and/or
power allocation. Sadri 126.
Yao also teaches a similar wireless communication system in which
channel monitor data (e.g., sensitivity and transmit power) is collected at a
wireless station (e.g., mobile terminal “MT”) for quality of service
determination in the context of a handoff from one AP to another AP. Yao
13. In particular, Yao describes that the wireless station (MT) may scan the
channel in two modes: (1) an “active scan” mode—similar to the “closed-
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Application 13/417,235
loop” mode disclosed by Sadri and Appellants’ Specification, where the
wireless station (MT) sends a request and waits for an AP to return a
response (including channel monitor data) for link adaptation; and (2) a
“passive scan” mode—similar to the “open-loop” mode disclosed by Sadri
and Appellants’ Specification, where the wireless station (MT) receives a
beacon frame (including channel monitor data) broadcasted by an AP for
link adaptation. Yao ]f 42. According to Yao, the channel monitor data
(a.k.a., “link metric” disclosed by Appellants) also includes “sensitivity and
transmission power on the AP.” Yao 42, 52.
Appellants dispute the Examiner’s factual findings regarding Sadri
and Yao. Appellants contend “neither Sadri nor Yao teaches a wireless
station that, without having sent a preceding request to an access point (e.g.,
base station), receives a value in a packet from the access point indicating
the power at which the packet was transmitted and the receiver sensitivity of
the access point.” App. Br. 7—12 (emphasis added). In particular,
Appellants contend “[njeither Sadri nor Yao teaches receiving a transmit
power value without first requesting the value, measuring the received signal
strength, and then using both the received and measured values to determine
a modulation scheme.” According to Appellants,
In the open-loop mode of Sadri, the transmitting device
(wireless station) that transmits to the remote device (base
station) does not first receive any channel state information (CSI)
from the remote device . . . Instead, the transmitting device in
Sadri must estimate the channel characteristics in the open-loop
mode without the benefit of first receiving channel state
information (CSI) from the remote device (base station). . .
in Sadri’s open-loop mode, the device that transmits to the
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remote device is not first a receiving device but rather is only a
transmitting device, as explained in paragraph [0038]. The
transmitting device (wireless station) in Sadri’s open-loop mode
must determine its own transmit characteristics based only on an
estimate of the channel characteristics without using any value,
metric or information received in a downlink packet from the
remote device.
Thus, in Sadri’s open-loop mode, there is no CSI request,
and Sadri’s transmitting device does not use CSI information
received from the remote device. Sadri does not teach a remote
device (access point or base station) that sends unrequested
information to Sadri’s transmitting device (wireless station)
indicative of the transmit power of the remote device or the
receiver sensitivity of the remote device. In Sadri’s open-loop
(blind) mode, the transmitting device that transmits to the remote
device (base station) receives no prior information from the
remote device.
Id. at 7—9 (emphasis added).
Appellants also argue the distinction between Appellants’ claimed
“open-loop metric value” and Sadri’s “open-loop (blind) mode.” Id. at 10.
According to Appellants,
Sadri’s “open-loop (blind) mode” is performed without receiving
any external information, i.e., blind. There can be no “open-loop
link metric value” in Sadri’s open-loop mode because the device
that transmits to the remote device receives no prior information
whatsoever from the remote device. On the other hand, the
recited “open-loop link metric value” is received from an access
point (base station) by the receiving module (wireless station) of
claims 1, 8 and 15 even though the wireless station or receiving
module did not first send a preceding request for that value to the
access point.
Id. at 11 (emphasis added).
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In addition, Appellants also contend “[n]either Sadri nor Yao teaches
receiving without first requesting a value in a packet from a base station
indicating the sensitivity of the base station’s receiver.” Id. at 11—12
(emphasis added). Specifically, Appellants acknowledge “paragraph [0042]
of Yao teaches an access point that sends ‘receiver sensitivity information,
as well as transmission power, to a station (See, e.g., [0042]).” Id. at 11.
However, Appellants argue (1) “Yao does not teach a wireless station that
receives a value in a packet from a remote device (base station) indicative of
the receiver sensitivity of the remote device without first having sent a
preceding request to the remote device” and (2) “[t]he word ‘sensitivity’
used in Yao relates to channel sensitivity as opposed to the sensitivity of a
receiver on a base station.” Id. at 11—12.
We do not find Appellants’ arguments persuasive. Instead, we find
the Examiner has provided a comprehensive response to Appellants’
arguments supported by a preponderance of evidence. Ans. 2—6. As such,
we adopt the Examiner’s findings and explanations provided therein. Id. At
the outset, we note the term “without sending a preceding request to the
access point” is redundant because the Examiner has implicitly interpreted
the phrase “receiving an ‘open-loop’ metric” as “receiving [a metric]
without having sent a preceding request.” Ans. 2.
In our view, the combination of Sadri and Yao teaches or suggests
Appellants’ proffered solution of “an open-loop fast link adaptation scheme”
in which a wireless station is configured: (1) to receive a downlink packet in
the form of a beacon or polling packet [periodically] transmitted from an AP
[including both sensitivity and transmit power on the AP], and based on
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receipt of the downlink packet, (2) to apply link adaptation, i.e., determine
the appropriate modulating and coding scheme (MCS).
For example, Sadri teaches devices (e.g., AP and wireless stations)
102, 104, shown in Figure 1, equipped with subcarrier management agents
(SMA) 112, 114 to perform adaptive control of channel-related parameters
in response to received channel state information (CSI) in two different
modes: (1) “closed-loop” mode, or (2) “open-loop” mode. Sadri || 17—20.
Sadri also teaches the use of channel state information (CSI) including
channel-related parameters such as received signal strength indicator (RSSI),
coding type, and modulation type and/or power allocation for link
adaptation. Sadri 126.
Similar to Sadri, Yao also teaches the use of channel monitor data
(e.g., sensitivity and transmit power) at a wireless station (e.g., mobile
terminal “MT”) in two similar modes: (1) an “active scan” mode (similar to
the “closed-loop” mode disclosed by Sadri and Appellants’ Specification),
where the wireless station (MT) sends a request and waits for an AP to
return a response (including channel monitor data) for link adaptation; and
(2) a “passive scan” mode (similar to the “open-loop” mode disclosed by
Sadri and Appellants’ Specification), where the wireless station (MT)
receives a beacon frame (including channel monitor data) broadcasted by an
AP for link adaptation. Yao H 3, 42. According to Yao, the channel
monitor data (a.k.a., “link metric” disclosed by Appellants) also includes
“sensitivity and transmission power on the AP.” Yao 42, 52.
A person skilled in the art is presumed to know all the relevant prior
art at the time of Appellants’ invention, including, for example: (1) the
difference between an “open-loop” mode and a “closed-loop” mode, as
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disclosed by Sadri || 17—20; (2) the broadcast of a downlink packet in the
form of a beacon or polling packet [periodically] transmitted from an AP
[including both sensitivity and transmit power on the AP], as disclosed by
Yao 42, 52; and (3) based on receipt of the downlink packet, to apply link
adaptation, i.e., determine the appropriate modulating and coding scheme
(MCS), as disclosed by Sadri H 19-20, 25—26 and Yao H 42, 52. See In re
GPACInc., 57 F.3d, 1573 (Fed. Cir. 1995). Those persons “must be [also]
presumed to know something” about the art “apart from what the references
disclose.” In re Jacoby, 309 F.2d 513,516 (CCPA 1962). Thus, that person
is presumed to have the technical competence and experience, including
sufficient skillset to use a downlink packet in the form of a beacon or polling
packet [periodically] transmitted from an AP [including both sensitivity and
transmit power on the AP], and based on receipt of that downlink packet,
apply link adaptation, i.e., determine the appropriate modulating and coding
scheme (MCS) in the manner recited in Appellants’ claims 1, 8, and 15.
Any effort to incorporate Yao’s teachings regarding the beacon packet
including both sensitivity and transmit power on an AP as part of Sadri’s
wireless communication system would have been obvious to those skilled in
the art because these well-known features perform the same known function
and yield no more than one would expect otherwise. KSR Int 7 Co. v.
Teleflex Corp., 550 U.S. 398, 406 (2007). A skilled artisan would “be able to
fit the teachings of multiple patents together like pieces of a puzzle” since
the skilled artisan is “a person of ordinary creativity, not an automaton.” Id.
at 420-21.
Lastly, we note Appellants have not demonstrated the Examiner’s
proffered combination of references would have been “uniquely challenging
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or difficult for one of ordinary skill in the art.” See Leapfrog Enters., Inc. v.
Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007) (citing KSR, 550
U.S. at 418). Nor have Appellants provided objective evidence of secondary
considerations which our reviewing court guides “operates as a beneficial
check on hindsight.” Cheese Systems, Inc. v. Tetra Pak Cheese and Powder
Systems, Inc., 725 F.3d 1341, 1352 (Fed. Cir. 2013).
For these reasons, we sustain the Examiner’s obviousness rejection of
independent claims 1,8, and 15 based on Sadri and Yao.
With respect to dependent claims 2—7, 9—14, and 16—20, we remain
unpersuaded by Appellants’ arguments presented and adopt the Examiner’s
responses provided on pages 6—10 of the Examiner’s Answer. Accordingly,
we also sustain the Examiner’s obviousness rejection of claims 2—7, 9-14,
and 16—20 based on Sadri and Yao.
CONCLUSION
On the record before us, we conclude Appellants have not
demonstrated the Examiner erred in rejecting claims 1—20 under 35 U.S.C.
§ 103(a).
DECISION
As such, we AFFIRM the Examiner’s final rejection of claims 1—20.
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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