Ex Parte 5077733 et al

Board of Patent Appeals and Interferences

Nov 29, 2010

90008522 (B.P.A.I. Nov. 29, 2010)

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.
90/008,522 03/30/2007 5077733 COM/001 3600
22852 7590 11/30/2010
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER
LLP
901 NEW YORK AVENUE, NW
WASHINGTON, DC 20001-4413
EXAMINER
DEB, ANJAN K
ART UNIT PAPER NUMBER
3992
MAIL DATE DELIVERY MODE
11/30/2010 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 BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte LG ELECTRONICS, INC.
____________

Appeal 2010-005184
Reexamination Control No. 90/008,522
United States Patent 5,077,733
Technology Center 3900
____________

DECISION ON APPEAL1
____________

Before SCOTT R. BOALICK, KARL D. EASTHOM, and KEVIN F.
TURNER, Administrative Patent Judges.

EASTHOM, Administrative Patent Judge.

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
shown on the PTOL-90A cover letter attached to this decision.

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Appellant, LG Electronics, Inc., the real party in interest of the patent
under reexamination, appeals under 35 U.S.C. §§ 134(b) and 306 from a
final rejection of claims 11-17. Claims 1-10, 18, and 19 are not under
reexamination and hence are not on appeal. (App. Br. 8.) We have
jurisdiction under 35 U.S.C. §§ 134(b) and 306.
We AFFIRM.

STATEMENT OF THE CASE
This proceeding arose from a third party request for ex parte
reexamination of United States Patent 5,077,733, titled “Priority Apparatus
Having Programmable Node Dwell Time” and issued to listed inventor
David L. Whipple. An oral hearing involving the instant appeal at the
USPTO was conducted on September 29, 2010 and was transcribed
[hereinafter BPAI Tr.].
The Disclosed Invention2
The ‘733 patent describes a “‘rotating daisy chain’” (col. 5, ll. 61-62)
system which determines priority of access to a bus by devices attached to
the bus at nodes. For example, memory and CPU devices compete for
access to such a bus. (See Fig. 1.) The system prioritizes device to bus
access so that any one device does not “hog” time of access. The ‘733
patent describes the system as follows:
For purposes of determining priority, the apparatus arranges the
nodes in a circular configuration and selects one of the nodes as
the “anchor node.” The anchor node has the highest priority
and the priorities of the other nodes are determined by their

2 The ensuing description constitutes findings of fact referenced below as
“D.”
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positions in the circle relative to the anchor node. Each node
includes a presettable counter for indicating a number of times
that a node may access the bus before the highest priority is
rotated to another node. After a device represented by one of
the nodes accesses the bus for a predetermined number of
accesses the current anchor node ceases being the anchor node
and the next node in the circle becomes the new anchor node.
The priorities of the nodes change to reflect the new location of
the anchor node.
(Abstract.)

Appellant describes the primary functions of the invention as
compared to the prior art, as follows:
[T]he invention . . . neither permits a single node to “hog” the
bus nor requires a node to wait to gain access to the bus when
no other node has a request pending. Furthermore, the
invention provides that once a node gains the highest bus
priority that it maintains the highest priority over the other bus
nodes for a programmable number of bus access cycles before
relinquishing the highest priority to another node.
(Col. 2, ll. 14-24.)
To reduce waiting when no other node has a request pending, a
“component [at node 603(1)] can seize the bus in either of two cases: if no
preceding node 603 has taken access [or] if a preceding node 603 has, but
node 603(1) is currently the anchor node.” (Col. 19, ll. 59-62.) To
determine this access, the system must arbitrate by waiting for each node in
the circular chain to respond to priority access signals. (Col. 19, l.16 to col.
20, l. 1). The system uses a SBS (System Bus Priority) Bus 106 to transmit
these priority access signals. These access signals propagate around the
physical bus loop causing minimal delays based on the signal propagation
speed around the bus and interface logic in each node processing such
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signals to produce a response. (Col. 13, ll. 57-67.) “Thus, there must be a
period for resolving access which is long enough to permit such response.
The length of the period will depend on the gate delays in each node 603 and
the number of nodes 603 in the circular chain.” (Col. 19, l. 67 to col. 20, l.
3.)
The anchor node (i.e., the node of current highest priority) moves to
the next node in the chain as components at each node in the chain use the
System Bus 104. (Col. 17; ll. 32-40; col. 18, ll. 31-38.) The opportunity to
gain access to the System Bus 104 passes from node to node via the
aforementioned logic signals:
[W]hen an element currently having access to System Bus 104
releases System Bus 104, the opportunity to gain next access to
[sic: the bus is] passed through SBP Bus 106 to the next
element along SBP Bus 106. That next element may take
access to System Bus 104 or, if it does not do so, passes the
opportunity for access to its next element along SBP Bus 106,
and so on until the element originally having access is reached
again or some element along SBP Bus 106 takes access to
System Bus 104.
(Col. 13, ll. 17-26.)

Any element having access “operates as a gate to prevent the
propagation of the opportunity to obtain access to the System Bus 104, that
is, the element may ‘capture’ the opportunity.” (Col. 13, ll. 51-54.)
After a device gains access to the bus, a presettable node grant
counter, the NGCNT 720(1), increments based on clock transition signals.
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The counter helps to determine how long each node gains bus access,
counting such bus accesses at each node.3 (Col. 21, ll. 31-34, 61-64.)
Claims
Exemplary claims 11, 12, and 15 on appeal read as follows:
11. Apparatus for determining priority of access to a bus among a set
of devices coupled to the bus comprising:
a group of nodes, each node representing a device and having a
priority and being responsive to requests to access the bus from the

3 This passage and a corresponding phrase in claim 15 (i.e., “counting a
number of accesses by the device to the bus”) of the ‘733 patent were
objects of dispute in related litigation. See LG Electronics, Inc. v. Asustek
Computer, Inc. et. al., 40-41, Case Nos. C 01-01326 CW, 01-01375 CW, 01-
01954 CW, 01-02187 (N.D. Ca. Aug. 20, 2002) (“Claim Construction
Order”). The Patent Owner argued before the court that “the specification
explicitly equates counting the number of accesses with counting the number
of clock signals.” Id. at 40. The court found the phrase to be more limiting
than argued because a device had to first satisfy certain conditions including
acquiring access before clock cycles were counted as accesses. Id. at 40-41.
On appeal, the Federal Circuit vacated the court’s summary judgment of
non-infringement involving the ‘733 patent (other patents and parties were
also involved in the litigation). See LG Electronics Inc. v. BizCom
Electronics, Inc. et al., 453 F.3d 1364, 1376 (Fed. Cir. 2006) (finding a
genuine issue of material fact as to whether the accused devices “count[] a
number of accesses” as recited in claim 15 of the ‘733 patent, and stating
that “the central issue is whether the bus is accessed on each clock signal so
that the clock signals, in effect, count the number of accesses to the bus.”).
In any event, Appellant does not argue here that any of the timers disclosed
in the rejections at issue here fail to provide the function of determining bus
accesses based on a distinction between measuring pre-determined bus time
as opposed to accesses. (See also Oral Tr. 9-10 (affirming no intent to argue
a distinction between predetermined time of access versus counts of access
in Craft).)
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represented device to provide access if no device represented by a node with
higher priority has requested access;
means for giving a single one of the nodes the highest priority;
means for giving the highest priority to a different node in response to
a predetermined number of accesses of the bus by a device; and
means for determining the priority of each node relative to the highest
priority node.
12. The apparatus set forth in claim 11 and wherein:
the means for determining the priority of each node relative to the
node currently having the highest priority is a circular configuration of the
nodes wherein the priority of a given node is determined by the node's
position relative to the highest priority node.
15. A method for determining priority of access to a bus among a set
of devices coupled to the bus, each device being represented for priority
purposes by a node in a group of nodes and each node having a priority
relative to a single node currently having the highest priority, the method
comprising the steps of:
receiving an access request in a node from a represented device;
determining whether any node with a higher priority has received an
access request;
if no such node has received an access request, permitting the device
to access the bus;
counting a number of accesses by the device to the bus; and
in response to predetermined number of accesses to the bus, giving
another node the highest priority.
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The Prior Art References
Jensen US 4,017,841 Apr. 12, 1977
Menot US 4,271,505 June 2, 1981
Stoffel US 4,536,874 Aug. 20, 1985
Craft US 4,987,529 Jan. 22, 1991

The Rejections
Claims 11-17 stand rejected under 35 U.S.C. 102(b) as anticipated by,
or alternatively, under 35 U.S.C. § 103(a) as obvious over, Menot.
Claims 11-17 stand rejected under 35 U.S.C. 102(e) as anticipated by,
or alternatively, under 35 U.S.C. § 103(a) as obvious over, Stoffel.
Claims 11-17 stand rejected under 35 U.S.C. 102(e) as anticipated by,
or alternatively, under 35 U.S.C. § 103(a) as obvious over, Craft.
Claims 11, 15, and 16 stand rejected under 35 U.S.C. § 102(b) as
anticipated by Jensen.
Prosecution History (PH)
During the initial examination of the ‘733 patent application (App.
Ser. No. 07/405792), the examiner stated as reasons for the allowance of
claim 4 (objected to as dependent on claim 1 which was rejected along with
other claims under obviousness-type double patenting) and claims 15-19 in
the ‘733 patent, the following: “The prior art of record fails to teach or
suggest the additional features of a counter means and the step of counting
the number of bus accesses.” (App. Ser. No. 07/405792, Non-final
Rejection 2, July16, 1990.) A terminal disclaimer obviated the double
patenting rejections (id., Notice of Allowance, July 26, 1991) and claim 4
was amended to its current independent form (id., Amendment, Oct. 11,
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1990). Current claims 11-17 appear in the same form as originally examined
and as issued in the ‘733 patent.
PRINCIPLES OF LAW
Claim Construction – Expired Patent on Reexamination
The ‘733 patent has expired. As such, under Ex parte Papst-Motoren,
1 USPQ2d 1655, 1656 (BPAI 1986), the “broadest reasonable” rule of claim
construction is not applicable primarily because claims cannot be amended
during a reexamination of an expired patent. Hence, claim construction
rules as followed in infringement suits serve as appropriate guides. See id. at
1656 (citing In re Prater, 415 F.2d 1393 (CCPA 1969)). Conversely, the
Board also stated that it would be error to read “inferential limitations” into
the claims. Papst-Motoren, 1 USPQ2d at 1657 (citation omitted)
(contrasting “construing express claim language” “narrowly” in light of the
specification with reading improper “inferential limitations” into a claim).
In any event, “the specification ‘is always highly relevant to the claim
construction analysis. Usually, it is dispositive; it is the single best guide to
the meaning of a disputed term.’” Phillips v. AWH Corp., 415 F.3d 1303,
1315 (Fed. Cir. 2005) (en banc) (internal citations omitted). Prosecution
history can also aid determining the meaning of a claim. Id. at 1317.
ANALYSIS
Issue 1 – Rejections Based on Menot
The Examiner rejected claims 11-17 as anticipated, and in the
alternative, as obvious, based on Menot. The issues involved with Menot
follow:
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Does Menot disclose “giving the highest priority to a different node in
response to a predetermined number of accesses of the bus by a device” as
set forth in claim 11?
Does Menot disclose “a group of nodes, each node representing a
device and having a priority and being responsive to requests to access the
bus from the represented device to provide access if no device represented
by a node with higher priority has requested access” as set forth in claim 11?
Does Menot disclose “counting a number of accesses by the device to
the bus” and “in response to a predetermined number of accesses to the bus,
giving another node the highest priority, as set forth in claim 15?
Menot’s Teachings
M1. Menot describes an arbitration system as follows:
In providing the first level of arbitration, the LPC [link port
controller] continually scans the STATION REQUEST FLAGS
(SREQ) of its respective stations according to their priorities.
Preferably, each station is given equal priority (i.e., a round-
robin scan) such that all stations have equal opportunity to
communicate via the link. In this manner, no station . . . will
dominate the link.
(Col. 9, ll. 18-25.)
Link 14 employs a “station-initiated arbitration technique” for
granting master control to a station 12 “at any time, rather than only at
specified time-periods.” (Col. 3, ll. 25-30; Col. 3, l. 66to col. 4, l. 3.) Each
link includes a link port 24 which includes an LPC 48 which has a main
function of arbitrating priorities among stations connected to the link. (Fig.
9, col. 8, l. 64 to col. 9, l. 25.)
When an active SREQ “is sensed, the LPC halts its scanning sequence
and determines at what step the scanning has stopped. The number of the
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step will correspond to the number of the requesting station.” (Col. 9, ll. 29-
33.) In other words, after a station presents an SREQ, “[t]his act places [the
station] in contention for master control of system communication[s] with
the other stations . . . . [and the station] must now pass the round-robin
arbitration scheme.” (Col. 13, ll. 1-7.)
M2. The grant of bus access control to any station is time-limited to a
pre-determined time period, the LHTO (link hold timeout), thereby reducing
the effective wait time of other stations. (Col. 2, ll. 13-16; col. 4, ll. 8-14;
col. 5, ll. 21-25.)
M3. After a LHTO signal is issued, the station of current access will
be disconnected, and the LPC will continue its arbitration scanning at the
next step from which it previously stopped. (Col. 9, l. 62 to col. 10, l. 8.)
Discussion
Appellant asserts that Menot does not teach “‘means for determining
the priority of each device relative to the highest priority node,’” as recited
in claim 11.4 (App. Br. 41.) Appellant asserts that in Menot, only the “node
having the permit/token can receive ownership of the communication link,”
thereby “eliminating the need for determining or even considering the
priority, or otherwise enabling arbitration.” (Id.)

4 While Appellant states in the Brief “Summary of Claimed Subject Matter”
that the three means for clauses in claim 11 are subject to 35 U.S.C. § 112, ¶
6 (App. Br. 10-11), Appellant does not present arguments asserting a lack of
structure. The bolded emphasis on the function “determining the priority”
supra supports this understanding and Appellant’s response to Judge
Turner’s question verifies it: “[W]e aren’t at this point making any specific
arguments based on the structure.” (Oral Tr. 5.)
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These arguments are not persuasive. Menot’s system is a round-robin
arbitration system. (M1.) While claim 12 was not separately argued, it
implies what satisfies the determining means of claim 11. That is, claim 12
recites that the determining means is “a circular configuration of the nodes
wherein the priority of a given node is determined by the node’s position
relative to the highest priority node.”
Menot’s round-robin arbitration system satisfies this circular
configuration and its function because Menot’s round-robin system keeps
track of position relative to the starting/anchor node and then determines by
the LPC scanning step which of the station nodes sent its SREQ access
requesting flag. That SREQ sending node will be granted access based on
its relative position “at any time.” (M1; accord Ans. 25, 37-38). And while
Menot describes a “[p]referabl[e]” embodiment of the system as a “round-
robin scan” system providing “equal priority,” Menot generally states that
“the LPC continually scans the STATION REQUEST FLAGS (SREQ) . . .
according to their priorities.” (M1 (emphasis added).)
Thus, Menot’s system tracks relative priority during scans to grant
access. After a station presents an SREQ, it is “in contention for master
control of system communications with the other stations . . . . and [the
station] must now pass the round-robin arbitration.” (Col. 13, ll 1-7.)
Moreover, the system keeps track of the next node at which to resume
scanning, thereby re-designating the highest priority node, or anchor node,
and all nodes relative thereto. (M2.)
The Examiner explains that each station “‘initiate[s] a
communication’” via an SREQ flag to show how Menot discloses a similar
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phrase in claim 14, “determining whether any node with a higher priority has
received an access request.” (Ans. 27-28; accord M1.) Appellant does not
respond in particular to the Examiner’s reliance on Menot’s SREQ flags, yet
acknowledges Menot’s “‘station-initiated arbitration technique.’” (Reply Br.
24.) Rather, Appellant describes Menot’s system as similar to the token-ring
systems of Jensen and Stoffel (discussed below). (Id. at 24-25.) For
example, Appellant argues that “Menot must first grant access to every other
device ahead of a requesting device–even if they have no pending requests–
before granting access to the requesting device.” (Reply Br. 27.) This
assertion ignores Menot’s station-initiated arbitration technique involving
the SREQ flags. Menot’s system grants access to SREQ requesting stations
as it scans for such requests. (M1, M3.)
Appellant also asserts that because Menot’s round-robin system grants
access to stations even if they do not request such access, the system does
not “‘provide access if no device represented by a node with higher priority
has requested access’” as claim 11 requires. (App. Br. 45.) This argument
fails because the premise is faulty as just explained – Menot’s system only
grants access to requesting stations. In a similar vein, Appellant argues that
“Menot does not provide network access to a lower level node when other
‘higher’ priority nodes have not requested access.” (App. Br. 45.)
This argument is also unpersuasive. Starting at the highest priority
anchor node in the round-robin system, Menot skips over (i.e., does not
grant access to) the higher priority nodes which fail to present an SREQ flag,
and then grants access to the next requesting lower (i.e., relative to the
skipped-over nodes) node in the round-robin cycle. Then, responsive to that
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lower node communicating its data and timing out based on the LHTO
signal (i.e., “in response to a predetermined number of accesses” as claim 11
requires), Menot’s LPC (re-)starts scanning at the next node in the round-
robin cycle, thereby shifting the highest priority to that node (i.e., the new
anchor node at which the re-start of the scan occurs). In sum, Menot skips
over higher priority non-requesting nodes, gives the highest priority to a
lower priority node which requests it (i.e., because “no device represented
by a node with higher priority has requested access”), and then after that
node times out (i.e., “in response to a predetermined number of accesses”),
effectively transfers the highest priority to the next node in the priority
scheme. (See M1-M3.) In other words, Menot anticipates claim 11.
Similarly with respect to claim 15, Menot’s system starts at the
highest priority node, scans and skips higher priority stations which have not
requested access, grants a lower requesting station access, counts accesses
after timing out the lower requesting station, and in response, transfers the
highest priority to the next station node in the scheme. In other words,
Menot’s system determines priority of access as it must via arbitration,
receives access requests, determines whether any node with a higher priority
has received an access request, and if no such node has received an access
request, permits a requesting device to access the bus, counts those accesses,
and in response, gives another node (either the next scanned node and/or the
next requesting scanned node) the highest priority, as required by claim 15.
Therefore, Menot satisfies the disputed steps (see App. Br. 42), and all steps,
of claim 15.
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With respect to the 102 and 103 rejections, the Examiner relies upon a
“Link Hold Timeout LHTO” period to anticipate or to render obvious the
phrase in claim 11, “a predetermined number of accesses,” and a similar
phrase in claim 15. (Ans. 24, 28-29.) These similar claim phrases are not in
dispute here in terms of any distinction involving pre-determined times
versus accesses, if there is such a distinction. (See supra note 3.) Thus, the
102 and 103 rejections present the same disputed issues.
Appellant’s arguments asserting that the Examiner employed an
incorrect claim construction standard under Phillips and Pabst-Motoren
refer to similar arguments asserted earlier in the Brief with respect to the
Jensen rejection. (App. Br. 41- 43.) To the extent the arguments apply here,
they primarily rest on the assertion that the ‘733 patent “avoid[s] token-ring
systems” and solves problems associated with those systems according to
certain disclosed objectives. (See App. Br. 19-20, 23-24.)
Contrary to Appellant’s arguments, the ‘733 patent’s disclosed
“‘rotating daisy chain’” system is similar to Menot’s rotating round-robin
system. (See D; M1; BPAI Tr. 7 (acknowledging similarities between the
‘733 round-robin system and the prior art).) As such, the ‘733 patent does
not avoid prior art token or other ring-type systems; rather, it modifies such
ring systems to address one or more prior art problems according to one or
more listed objectives. Menot’s system satisfies at least some of, if not all
of, the avowed objectives of the disclosed invention. The “fact that a patent
asserts that an invention achieves several objectives does not require that
each of the claims be construed as limited to structures that are capable of
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achieving all of the objectives.” Leibel-Flarsheim Co. v. Medrad, Inc., 358
F.3d 898, 908 (Fed. Cir. 2004).
The aforementioned objectives disclosed in the ‘733 patent follow:
1) preventing bus hogging, 2) allowing a device to maintain the highest
priority for a programmable number of cycles (to account for different
access times according to each device), and 3) preventing a node from
waiting to gain access to the bus when no other node has a request pending.
(See D; accord App. Br. 19-20.)
Even if claims 11 and 15 require (by implication) one or more of these
disclosed objectives, Menot’s round-robin system prevents node dominance
(i.e., hogging) and provides quick access by scanning over non-requesting
nodes (M1-M2), thereby satisfying the ‘733 patent’s first and third
objectives.5 As to the second objective, Menot implies other than equal
priority schemes by indicating the equal priority scheme is simply an option
and stating that stations are scanned according to their priorities, implying
unequal bus access types of priorities for nodes requiring more or less
frequent bus access. (See M1.)

5 As disclosed in the ‘733 patent, lower priority devices cannot jump over
higher priority devices which have requested access and must still wait for
the arbitration determination (even if that determination happens faster than
occurs in prior art systems). (See D.) Thus, while Appellant argues that the
‘733 patent allows nodes to obtain priority “out of turn” (Reply Br. 11), does
not require a device “to wait to gain access,” and describes a lack of a wait
period (App. Br. 20), the disclosed system does require a small wait period
(for arbitration) which increases as the number of device nodes increase (D),
similar, at least in that respect, to Menot’s system. Also, Menot’s system
can grant access at any time to requesting devices, indicating that devices
can similarly jump “out of turn” (i.e., while waiting for the arbitration
determination). (Compare M1 with D.)
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Satisfying (at least some of) the disclosed objectives in a fashion
similar to the disclosed invention indicates that Menot’s system meets
claims 11 and 15 under the proper claim construction standard. See Leibel-
Flarsheim Co., 358 F.3d at 908. Moreover, the prosecution history indicates
that the claims were drawn to distinguish over prior art systems based on the
claimed feature of counting bus accesses (see PH) – a feature not in dispute
with respect to the Menot rejection (and not explicitly recited in claim 11).
In other words, the prosecution history does not imply in a clear fashion that
claims 11 and 15 were drawn to cover all three objectives such that all three
objectives would be implicit in any claim language identified by Appellant.
Finally, Appellant argues that the prosecution history of the ‘733
patent, including statements made during the initial examination, the
reexamination, and here on appeal, limit the scope of the claims. (Reply Br.
14.) Appellant has not demonstrated how any statements made during the
initial examination limit the claims in a manner which distinguishes over
Menot (see PH and discussion supra). And while any statements made
during reexamination may limit the claim scope in litigation proceedings
subsequent thereto, the cases cited by Appellant (Reply Br. 14) do not
require or allow the Board to limit the claims as argued during this
proceeding.
Based on the foregoing discussion, the Examiner did not err in
determining that Menot anticipates and/or renders obvious claims 11 and 15,
and claims 12-14, 16, and 17 which are dependent therefrom and which fall
therewith as not having been separately argued. As such, we will sustain the
Examiner’s anticipation and alternative obviousness rejections of claims 11-
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17 based on Menot. See Meyer, 599 F.2d at 1031 (claims obvious if
anticipated).
Conclusion
Menot discloses “giving the highest priority to a different node in
response to a predetermined number of accesses of the bus by a device” as
set forth in claim 11.
Menot discloses “a group of nodes, each node representing a device
and having a priority and being responsive to requests to access the bus from
the represented device to provide access if no device represented by a node
with higher priority has requested access” as set forth in claim 11.
Menot discloses “counting a number of accesses by the device to the
bus” and “in response to a predetermined number of accesses to the bus,
giving another node the highest priority,” as set forth in claim 15.
Issue 2 – Rejections Based on Stoffel
The Examiner rejected claims 11-17 based on Stoffel as anticipated
and in the alternative, as obvious based on Stoffel. The issues involved with
Stoffel track those with respect to Menot.
Stoffel’s Teachings
(S1.) Stoffel’s round-robin priority system passes an access granting
permit (token) to each transceiver requiring access. Each transceiver
contains permit passing circuitry to pass the token to the next recipient by
keeping a list of addresses of terminals which are to receive the token. Each
designated transceiver recipient accepting the token acknowledges the token.
If the designated transceiver fails to acknowledge the token, the permit
passes to the next transceiver in the loop according to the next transceiver in
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the list. Also, when the designated node which presently holds the token
does not have data to transmit, it passes the permit to the next transceiver in
the system. (Col. 4, ll. 36-68; col. 11, ll. 38-42.)
(S2.) “The inoperative terminal does not accept the permit nor
acknowledge receipt of the permit.” (Col. 11, 37-38.) “In the event that the
designated terminal is not in operation, no acknowledgement signal is
generated, and the permit-passing circuitry updates the address to the
following one of the stored addresses.” (Col. 4, ll. 60-63.)
(S3.) Stoffel limits transmission time of bus access for each device
node to t-2 via a timer T-2. (Col. 8, ll. 7-14.) After the timer T-2 times out
(state 516, Fig. 6), the device node enters the permit transfer state (530, Fig.
6).
(S4.) Each data sending device initiates a request for data by setting a
data-to-send flag 220 to an output buffer 209 in each transceiver node 20.
(Col. 7, ll. 20-26; Fig. 1; Fig. 2.)
(S5.) Stoffel describes a two-tiered “Gamma” token passing system
in which each tier constitutes a round-robin system, but with one tier having
a higher priority than the other tier. The token passes to the lower priority
tier only once per cycle of the upper priority tier – granting fewer bus
accesses on a per device basis to lower tier devices. (Col. 16, ll. 3-23.)
Discussion
Appellant’s arguments are similar to the arguments presented against
Jensen and Menot. For example, Appellant asserts that once Stoffel’s
system provides a token “to a node, the remaining nodes cannot access the
network (i.e., no network contentions).” (App. Br. 26.) Based on this
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argument and the argument that the claimed invention requires a plurality of
status levels, Appellant contends that Stoffel does not meet claims 11 and
15. (Id. at 26-27.) These arguments are not persuasive. Claims 11 and 15
do not require network contentions or a plurality of status levels. And even
if Stoffel’s system prevents other nodes from taking access at the same time
a specific node holds a token as Appellant argues, the ‘733 patent similarly
discloses that a device “operates as a gate to prevent the propagation of the
opportunity to obtain access to the System Bus 104, that is, the element may
‘capture’ the opportunity.” (D.)
Appellant relies on an asserted lack of network contentions and a
summary of Stoffel’s system to conclude that Stoffel does not teach “‘giving
the highest priority to a different node in response to predetermined number
of accesses of the bus by a device,’ as claim 11 requires.” (App. Br. 26.)
This argument is not clear because it is not clear how an alleged lack of
network contentions relates to a predetermined number of accesses. The
focus on “priority” is also unclear. Stoffel’s system is priority based. (S1,
S5.) Appellant also does not explain how or argue that Stoffel’s time-based
token passing system including the time limit t-2 (S3) fails to constitute
passing priority based upon a predetermined number of accesses. (See supra
note 3; App. Br. 24-30.)
Appellant also argues that Stoffel does not disclose or suggest
“‘provid[ing] access if no device represented by a node with higher priority
has requested access’” because nodes are sequentially provided access even
if the nodes have not requested access. (App. Br. 27.) This argument is not
persuasive. Stoffel’s nodes must first request access with a data-to-send flag
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in order to transmit data. (S4.) Appellant’s arguments do not demonstrate
how a node’s acceptance of a token fails to satisfy any claim limitation or
how it constitutes providing access without requesting it. Additionally,
nonfunctioning nodes do not accept tokens and are passed over. (S1, S2.)
Appellant’s argument that Stoffel’s system fails to determine priority
also is not persuasive. (App. Br. 27-28.) As stated supra, Stoffel’s system
is priority based. (S1, S5.) It tracks priority by keeping track of the next
node in the round-robin system. Each node must keep track of the next node
in the priority chain by using an address list. If nodes in the system fail to
acknowledge or otherwise accept the token, the current node holding the
token must determine the next node in priority to which to send the token.
(S1, S2, S5.)
Accordingly, based on the arguments presented, Stoffel satisfies the
claims. Starting at the highest priority (changing) node in the round-robin
system, Stoffel’s system skips over (i.e., does not grant access to) the higher
priority nodes (designated by their relative positions in the address list)
which fail to request access via a flag (or fail to acknowledge the token –
inoperative devices), and then grants access to the next requesting lower
node in the round-robin cycle which sends an acknowledgement signal
based on receipt of the token. This system constitutes “a group of nodes,
each node representing a device and having a priority and being responsive
to requests to access the bus from the represented device to provide access if
no device represented by a node with higher priority has requested access,”
as set forth in claim 11. It also constitutes “receiving an access request in a
node from a represented device; determining whether any node with a higher
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priority has received an access request; [and] if no such node has received an
access request, permitting the device to access the bus;” as set forth in claim
15.
Then, responsive to that lower node communicating its data and
timing out based the timer T-2 (S3) (i.e., “in response to a predetermined
number of accesses” as claim 11 requires, and similarly “counting a number
of accesses” as claim 15 requires (supra note 3)), Stoffel’s token holding
node resumes the token passing attempts starting at the next node listed in
round-robin address list, thereby shifting the highest priority (anchor node)
to that next-listed node. This system constitutes “means for giving a single
one of the nodes the highest priority; [and] means for giving the highest
priority to a different node in response to a predetermined number of
accesses of the bus by a device,” as set forth in claim 11, and similarly
constitutes the corresponding method steps recited in claim 15. The “means
for determining the priority of each node relative to the highest priority
node,” as set forth in claim 11, appears as described supra.
Appellant’s arguments asserting that the Examiner employed an
incorrect claim construction standard under Phillips and Pabst-Motoren
refer to the earlier arguments in the Briefs. (App. Br. 28-30.) As indicated
supra, while Stoffel’s system is a token-based system, recorded distinctions
over the prior art according to the examiner in the underlying ‘733 patent
prosecution were based on the claim 15 limitations related to counting a pre-
determined number of accesses (PH), features which Appellant does not
contend are lacking in Stoffel and which are not recited in claim 11. Also,
Stoffel’s token system prevents node dominance (i.e., hogging) and provides
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quick access by skipping over non-requesting or non-functioning device
nodes, thereby satisfying the first and third objectives of the ‘733 patent
discussed supra. 6 Satisfying at least some of the avowed purposes of the
‘733 patent indicates proper claim construction. See Leibel-Flarsheim, 358
F.3d at 908.
Based on the foregoing discussion, the Examiner did not err in
determining that Stoffel anticipates and/or renders obvious claims 11 and 15,
and claims 12-14, 16, and 17 which are dependent therefrom and which fall
therewith as not having been separately argued. As such, we will sustain the
Examiner’s anticipation and alternative obviousness rejections of claims 11-
17 based on Stoffel. See Meyer, 599 F.2d at 1031 (claims obvious if
anticipated).
Conclusion
Stoffel discloses “giving the highest priority to a different node in
response to a predetermined number of accesses of the bus by a device” as
set forth in claim 11.
Stoffel discloses “a group of nodes, each node representing a device
and having a priority and being responsive to requests to access the bus from
the represented device to provide access if no device represented by a node
with higher priority has requested access” as set forth in claim 11.

6 Thus, notwithstanding that Stoffel discloses a “token-ring” system and
Appellant argues that the ‘733 patent distinguishes over such a system,
Stoffel’s token system includes a “round-robin or like sequence” (App. Br.
26 (quoting Stoffel)) and resembles the ‘733 patent’s disclosed “‘rotating
daisy chain’” system (D) based on the similarly provided objectives.
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Stoffel discloses “counting a number of accesses by the device to the
bus” and “in response to a predetermined number of accesses to the bus,
giving another node the highest priority, as set forth in claim 15.
Issue 3 – Rejections Based on Craft
The Examiner rejected claims 11-17 based on Craft as anticipated and
in the alternative, as obvious. Setting aside the anticipation issue, the issue
is whether Craft renders it obvious to track the time of access (i.e., the
number of accesses) for an individual bus master.
Craft’s Teachings
C1. Craft’s system employs a bus access arbitration system which
grants access to the device with the highest priority:
The bus arbitration circuit includes control signal inputs from
each of the bus masters to indicate when a bus master is
requesting access to the shared bus. The bus arbitration system
responds to the request or requests from the bus masters, from
the refresh circuitry and from the conventional [direct memory
access] DMA-based peripheral controller and determines which
of the requesting devices has the highest priority. The bus
arbitration system grants control of the shared bus to the master
or other requester having the highest priority.
(Col. 4, ll. 40-47.)

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(C2.) Craft’s Figure 5 is depicted below:

Craft’s Figure 5 shows three bus masters, a refresh circuit, and a
DMA controller connected to a bus arbitration control circuit.
C3. Craft discloses a watchdog timer set for a predetermined amount
of time sufficient to permit a bus master to transfer a burst of data to
memory via a shared bus. The time is short enough so that the
microprocessor will obtain control of the bus within a reasonable amount of
time. (Col. 5, ll. 20-31.) Typically, the predetermined amount of time
corresponds to the time required to transfer 512 bytes of data. (Col. 21, ll.
41-45.)
C4. In preferred embodiments, access priority among bus masters is
rotated so that the current bus stores a code indicating that it will have the
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lowest priority during the next arbitration cycle. (Col. 5, ll. 41-46; col. 26,
ll. 31-37.)
Thus, for example, when the BUS MASTER A 350 is granted
control of the shared bus 318, the new priority will be such that
the BUS MASTER B 352 will have the highest priority during
the next arbitration, the BUS MASTER C 354 will have the
next highest priority, and the BUS MASTER A 350 will have
the lowest priority.
(Col. 26, ll. 50-57.)
C5. Craft discloses re-initiating the watchdog timer each time (under
certain conditions) the bus arbitration circuit honors a different bus master
request to gain access. (Col. 29, ll. 31-35.)
C6. Craft discloses granting a DMA controller for only a single
memory cycle (i.e., “a single data byte” – col. 14, l. 39) to allow the
microprocessor to maintain control. (Col. 9, ll. 46-52.) Similarly, Craft
discloses allowing a refresh circuit to access system memory for a memory
cycle. (Col. 9, ll. 13-21.)
Discussion
Appellant argues that Craft fails to suggest “means for giving the
highest priority to a different node in response to a predetermined number of
accesses of the bus by a device” as claim 11 requires. According to
Appellant, Craft tracks cumulative time for the three bus masters as a group
and that such cumulative tracking is not in response to a predetermined
number of accesses by a device. (App. Br. 55.)
The Examiner responds by finding that Craft teaches allowing
sufficient access time to allow a bus master to “complete [a burst] data
transfer of a reasonable length.” (Ans. 46.) Based in part on this finding,
the Examiner reasons that it would have been obvious to have modified
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Craft’s system to include counting the number of accesses for each single
bus master to allow each bus master to retain control for a predetermined
time sufficient to transfer a block of data without taking too much control
time from the microprocessor. (See Ans. 7, 46.) After this proposed
modification, Craft’s system would transfer the highest priority to one of the
other bus masters, or the microprocessor, according to its normal routine.
(See Ans. 6-7, 40; C4.)
C7. Craft amplifies the Examiner’s cited teaching (Ans. 46 (citing
col. 21, ll 33-39)) as follows:
The predetermined time that the first timer output signal
is active is selected to be sufficiently long t[o] allow a bus
master to complete a burst data transfer of a reasonable length,
yet sufficiently short that bus arbitration control circuit 370 will
regain control of the shared bus 318 so that it may grant control
of the shared bus 318 to the microprocessor 310 after a
reasonable length of time, so that, for example, the
microprocessor 310 may use the shared bus 318 to perform
non-interrupt instructions. For example, in one application, the
predetermined time that the first timer output signal is active is
programmed to be approximately the amount of time required
to transfer 512 bytes of data, allowing time for the anticipated
delay caused by the interposed refresh operations. The first
watch dog timer circuit 460 is programmable so that the
predetermined time can be varied in accordance with the type of
applications that the computer system 300 is intended or in
accordance with the type of peripheral devices to be serviced by
the bus masters.
(Col. 21, ll. 33-52.)
In other words, as the passage shows and as the Examiner found, Craft
reasonably suggests timing or controlling the amount of time, or
equivalently, the number of bus accesses (i.e., data byte transfers) by each
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individual bus master. For example, Craft discusses timing control based on
a number of bus accesses corresponding to 512 bytes of memory transferred
by each bus master. Such a memory transfer allows sufficient transfer
without taking too much time (i.e., hogging time) from the microprocessor.
(Ans. 6-7, 11, 39-40; C3, C7.) Craft similarly teaches limiting accesses (i.e.,
a single memory cycle – a data byte) for other devices (e.g., the DMA and
the refresh circuit) for the same reason (see C6), further suggesting a similar
access limit on any other device, such as a bus master. Craft also discloses
that the watchdog timer circuit is programmable “so that the predetermined
time can be varied in accordance with the type of . . . peripheral devices to
be serviced by the bus masters.” (C7.)
Under this (Examiner-modified) predetermined number of accesses by
each of from one to three of the bus masters, Craft teaches transferring
priority to one or the other of the bus masters or to the microprocessor as the
Examiner also found. (See Ans. 6-8; 46; C1, C3, C4, C6, C7.)
Thus, while Craft does disclose tracking the aggregate time of more
than one bus master as Appellant argues, Craft aggregates the time to ensure
that at least one bus master can transfer data efficiently during the time
allotted by the first watchdog timer. As such, and based on the foregoing
discussion concerning the tailoring of accesses according to specific devices,
Craft suggests individually counting the number of bus master accesses to
the bus in order to ensure an ideal amount of data transfer for each bus
master, depending on the specific devices attached to each bus master. Craft
also discloses resetting the watchdog timer each time (under certain
conditions) a new bus master gains access (C5) – further suggesting
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individual control of the number of accesses for each bus master device in
light of the other teachings. Accordingly, Appellant’s argument that Craft
only discloses or suggests aggregate bus access for all three bus masters is
not persuasive.
Appellant also asserts that “Craft discloses that reassignment of
priority is in response to granting a bus master control of the shared bus,
not ‘in response to a predetermined number of accesses of the bus by a
device,’ as recited in claim 11.” (App. Br. 55.) This argument is not
persuasive. This bus master priority shift is implemented during the next
arbitration cycle (C4), and not as Appellant argues at the outset when the
previous bus master first gains access. Appellant is correct in that the
mechanism for transferring the highest priority to the next bus begins at the
outset of the previous bus access, but the highest priority is granted to the
next designated bus during the next arbitration cycle. (C4.) Some of
Appellant’s other remarks indicate agreement with this factual finding. (See
Reply Br. 31 (quoting Craft and describing initial code storage and
thereafter granting “‘a new priority so that the bus master to which control
[is] granted will have the lowest priority during the next arbitration.’”
(emphasis added).)
Thus, under the proposed modification by the Examiner, it follows
that the next arbitration cycle would only occur after the previous bus master
exhausts its bus accesses according to the modified watchdog timer/counter.
As such, under the proposed rejection in which each bus master is allocated
a set number of bus accesses according to a modified version of Craft’s
watchdog timer scheme, transferring the highest priority from a first bus
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master to another bus master (or the microprocessor) occurs after the first
bus master times out, i.e., in response to the number of accesses of that first
bus master, even if such a response is not immediate. The ‘733 patent
operates in a similar fashion. (See D.)
As indicated supra, Appellant and the Examiner discuss the “highest
priority” in relation to Craft’s three bus masters between which priority
rotates.7 (C4) This rotating priority is similar to the ‘733 disclosed scheme.
(D.) As also indicated supra, the Examiner also describes transferring the
“highest priority” (Ans. 6, 46) to the microprocessor 310 in response to a
predetermined number of bus accesses by one or more of the bus masters.8
(Ans. 6-7.) Appellant does not respond to, and thereby waives arguments
against, this alternative rationale concerning the microprocessor. Claims 11
and 15 are broad enough to be satisfied by transferring the highest priority
between one of the bus masters (after counting accesses under the proposed
modification as discussed supra) or to the microprocessor in Craft as the
Examiner found.
Appellant’s arguments for patentability of claim 15 and the
Examiner’s findings and responses thereto track those for claim 11. The
disputed phrases of the claims are of similar scope in terms of the arguments
presented. (See App. Br. 56-57; Reply Br. 35.)
Based on the arguments presented, the Examiner has not erred in
determining that Craft renders claims 11 and 15 obvious. Dependent claims

7 See e.g., the Examiner’s reproduction of Craft’s “Bus Grant” versus “New
Priority” table. (Ans. 7.)
8 Craft also refers to determining the highest priority among the DMA, the
refresh circuit, and the bus masters. (C1, C2.)
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12-14 and 16-17 fall with claims 11 and 15 as not having been argued
separately. As such, we will sustain the Examiner’s obviousness rejection of
claims 11-17 based on Craft.
Conclusion
Craft suggests “giving the highest priority to a different node in
response to a predetermined number of accesses of the bus by a device” as
set forth in claim 11.
Craft suggests “counting a number of accesses by the device to the
bus” and “in response to a predetermined number of accesses to the bus,
giving another node the highest priority, as set forth in claim 15.
Issue 4 - Rejection Based on Jensen
The rejection based on Jensen is cumulative to the rejections
discussed supra. As the above-discussed rejections are dispositive, it is not
necessary to decide whether the Examiner’s rejection based on Jensen is in
error.
DECISION
The Examiner’s decision to reject appealed claims 11-17 is affirmed.
Requests for extensions of time in this ex parte reexamination
proceeding are governed by 37 C.F.R. § 1.550(c). See 37 C.F.R. § 41.50(f).

AFFIRMED

rvb

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Patent Owner:

FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER, LLP
901 NEW YORK AVENUE, NW
WASHINGTON, DC 2001-4413

Third Party Requester:

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