Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02320012 2000-09-18
1
SYSTEM FOR COMMUNICATING MESSAGES VIA A FORWARD
OVERHEAD CONTROL CHANNEL FOR A PROGRAMMABLE LOGIC
CONTROL DEVICE
Related Applications
The present application is related to Canadian Patent Application Serial
No. 2,185,230, filed on August 4, 1994, and to Canadian Patent Application
Serial No.
2,275,410, filed October 30, 1997 (PCT).
Technical Field
The present invention relates generally to data communications
systems and more particularly relates to protocols for communicating with a
programmable logic control device by sending a data sequence, typically one or
more
pages, via a forward overhead control channel of a cellular network control
channel
for a cellular mobile radiotelephone system.
Background of the Invention
In recent years, the communications industry has shown a growing interest in
various types of wireless communications systems for communicating voice
andlor
data between numerous remote sites and a central location. It is well
recognized that
the use of a dedicated telephone facility for a conventional telephone system
is not a
convenient or economical option for all communications applications. For
example,
for many industrial applications, a central data collection site has a need
for acquiring
information from a variety of remotely located monitoring devices that collect
data
about the operation or performance of equipment. To overcome the limitations
of the
conventional telephone system, a two-way wireless communications link is often
necessary to permit a response to a communication initiated from another
location. In
an attempt to solve the problem of supplying a response to an initial
communication,
the industry has offered various wireless communications systems, including
two-way
radios, cellular mobile radiotelephones, and paging systems.
CA 02320012 2004-04-08
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To overcome the limitations of prior communications systems, the assignee for
the
present invention has developed a system for communicating data via a cellular
network
control channel of a cellular mobile radiotelephone (CMR) system. U.S. Patent
Nos.
5,526,401; 5,546,444 and 5,873,043, which are assigned to the assignee for the
present
application and which may be referred to for further details, describe an
adapted use of the
existing architecture of a CMR system in an efficient and cost-effective
manner to support
communications via the CMR system, including collection and reporting of data
obtained at
remote sites.
The data message system described in the referenced U.S. patents includes data
reporting devices, at least one mobile switching center (MSC) and a data
collection system
connected directly or indirectly to the MSC or a Signal Transfer Point (STP).
The MSC can
issue commands or instructions, typically in a sequence of page messages, to
the data
reporting devices via the cellular network control channel of the CMR system.
Each data
reporting device can monitor the operation of a remote data source to collect
selected data or
can control the operation of a remote item in response to commands transmitted
over the via
the MSC. The data reporting device can transmit a data message containing the
selected data
via a cellular network control channel of the CMR system when the data
reporting device first
identifies itself or "registers" for operation with the MSC. Alternatively,
the data reporting
device can send the selected data via the cellular network control channel in
a data message
formatted to represent a "call origination" signal. In turn, the MSC can send
the data message
to the data collection system via a communications link. In this manner, the
data message
system takes advantage of an installed base of cellular communications
equipment by using
the cellular network control channel for data communications between a central
location and
one or more remote sites.
The data reporting device of the data message system typically communicates
with
the MSC via the reverse overhead control channel (RECC) of the cellular
network control
channel. In contrast, the MSC can communicate with a cellular-compatible
device, such as
a data reporting device, via the forward overhead control channel (FOCC) of
the cellular net-
work control channel. The conventional technique for sending a message to a
cellular mobile
radiotelephone from an MSC is the transmission of a page message over the
FOCC. For
example, a conventional cellular mobile radiotelephone can be stimulated by a
transmission
of the MSC to locate the mobile telephone unit when an incoming call from a
landline has
been placed to this unit. The data requirement for this type of trigger
message is minimal for
CA 02320012 2000-09-18
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conventional cellular communications and, consequently, each message is
independently processed as a complete data packet. This works well for the
paging
operations conducted by an MSC with conventional cellular mobile
radiotelephones
via the FOCC. However, this mechanism significantly limits the amount of
information or instruction that can be provided by the MSC to a data reporting
device
via a page carried by the cellular network control channel. This is a
disadvantage for
applications requiring the communication of a commands and/or data via the CMR
system to a remote cellular communications device for use by a controller,
such as a
programmable logic controller (PLC), coupled to a controllable item or
instrument.
In view of the foregoing, there is a need for adapting the paging mechanism of
a CMR system to support the transfer of commands and/or data for
communications
from an MSC to a cellular-compatible device. There is a further need for
communicating with and controlling the operations of a remote controller, such
as a
PLC, coupled to a cellular-compatible device that can accept commands and/or
data
via the paging mechanism of a CMR system.
Summary of the Invention
The present inventions solves the needs of the prior art by providing a method
for communicating with cellular communication devices by sending multiple
pages
via a cellular network control channel of a cellular mobile radiotelephone
(CMR)
system. Each cellular communications device operating within the coverage area
of
the CMR system can monitor the Forward Overhead Control Channel (FOCC) of the
cellular network control channel for a pair of pages, commonly described as
target
pages, within a first time period. Each target page includes a specific
identifier
assigned to one or more of the cellular communications devices. Each cellular
communications device maintains a mask in memory for storing one or more
specific
identifiers assigned to that device. In the event that a cellular
communications device
receives a page, such as the target page, having a matching specific
identifier, the
device will complete an action responsive to that page. Otherwise, a cellular
communications device will ignore a page having a specific identifier that
does not
match an identifier assigned to that device.
In response to receiving a pair of pages having a matching specific identifier
within the first time period, typically 60 seconds, the cellular
communications device
monitors the cellular network control channel over a second time period for at
least
one data page having a predetermined characteristic designating the page as
carrying
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data. For a data page formatted as a cellular telephony signal having a Mobile
Identification Number (MII~ field, the predetermined characteristic can be
defined as
a 2, 3, 4, 5 or 6 positioned in the least significant digit (LSD) of the MIN
carned by
that page.
In response to receiving at least one data page having a predetermined
characteristic during the second time period, the cellular communications
device can
collect the data carried by the received data page. This data can be stored at
the
cellular communications device for subsequent use or is forwarded for
processing by
another device, such as a programmable logic controller (PLC). To acknowledge
receipt of the data, the cellular communications device can send an
acknowledgement
signal via the cellular network control channel. This acknowledgement signal
can be
formatted as a cellular telephony Autonomous Registration signal and carries
an
indication of data verification. A mobile switching center (MSC) typically
receives
the acknowledgement signal via the Reverse Overhead Control Channel (RECC) of
the cellular network control channel.
For one aspect of the invention, the cellular communications device can
continue to monitor the FOCC for a second consecutive data page if the
predetermined characteristic in the first received data page specifies that a
pair of
consecutive pages carry data. This monitoring operation is typically carned
out over
the second time period. If the second data page is received during the second
time
period, then the cellular communications device can collect the data carned by
both
the first and second pages. The combination of data collected from the first
and
second pages can be forwarded by the cellular communications device to the PLC
via
a wired or wireless communications link. The cellular communications device
can
verify receipt of the data carned by both pages and issue an acknowledgement
signal
via the RECC to acknowledge receipt of such data. This acknowledgement signal
can
be formatted as an Autonomous Registration signal comprising an Acknowledge
Pattern (AAA hex) within the upper 12 bits and collected data, represented in
BCD,
big-endian order format, within the lower 12 bits.
For another aspect of the invention, a cellular communications device can
terminate monitoring operations prior to expiration of the second time period
if the
predetermined characteristic in the first received data page specifies that
only a single
page carries data. The cellular communications device can collect the data
carried by
the first data page and issue an acknowledgement signal via the RECC to
acknowledge receipt of the data carried by that page. This acknowledgement
signal
CA 02320012 2000-09-18
can be formatted as an Autonomous Registration signal comprising an
Acknowledge
Pattern (AA.AAA.A hex) within the upper 24 bits and collected data represented
in
BCD, big endian order format, within the lower 8 bits.
The present invention also provides a method for communicating a
5 programming command to a controller, such as a PLC, by sending multiple
pages via
the cellular network control channel of a CMR system. The PLC is typically
coupled
to a cellular communications device via a wired or wireless communications
link.
The cellular communications device can monitor the FOCC of the cellular
network
control channel for a target page having a specific identifier assigned to
that
communications device. Timely receipt of one or more target pages having a
specific
identifier assigned to the cellular communications device within a
predetermined time
period prompts that device to monitor the FOCC for a schedule page.
In response to receiving the target page(s), the cellular communications
device
can monitor for a time period the FOCC for a schedule page having a schedule
command. The schedule command identifies a slot number in a look-up table
maintained in memory by the PLC. This slot number represents a specific
storage
location within the look-up table for maintaining a programming command for
the
PLC.
In response to receiving the schedule page during the time period, the
cellular
communications device can forward the slot number to the PLC via the
communications link. In turn, the PLC can retrieve from its look-up table the
programming command identified by the slot number and initiate a program
action
associated with that programming command. The cellular communications device
also can send an acknowledgement signal via the cellular network control
channel to
acknowledge receipt of the schedule command.
The present invention further provides a method for communicating a
reprogramming command to a PLC by sending multiple pages via a cellular
network
control channel of the CMR system. A cellular communications device, which is
coupled to the PLC, monitors the FOCC for one or more target pages having a
specific identifier assigned to that device. In response to receiving target
pages) with
a matching specific identifier during a time period, the cellular
communication
devices monitors the FOCC for a schedule page having a schedule command. The
schedule command identifies a slot number specifying a particular stock in the
PLC's
look-up table containing programming data. In response to receiving the
schedule
page during a time period, the cellular communications device monitors the
FOCC for
CA 02320012 2000-09-18
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a data page carrying new programming data. Responsive to receiving the data
page,
the cellular communications devices forwards to the PLC the slot number and
the new
programming data. In addition, the cellular communications device sends an
acknowledgement signal via the cellular network control channel to acknowledge
receipt of the slot number and programming data.
In view of the foregoing, it will be understood that a cellular communications
device operating within the coverage area of a CMR System can receive multiple
pages via the FOCC and provide data extracted from one or more of these pages
to a
controller, such as PLC. The PLC, which is typically coupled to a controllable
instrument, can accept the extracted data as programming data representing new
or
replacement program commands. In contrast to the prior art, the communication
of
programming data to a PLC requires the reception of multiple pages by a
cellular
communications device via the FOCC. These and other objectives of the present
invention will become evident upon a review of the detailed description, the
drawing
set and the appended claim set.
Brief Description of the Drawings
FIG. 1 is a block diagram of a data message system constructed in accordance
with an exemplary embodiment of the present invention.
FIG. 2 is a diagram that shows the format for a data message that is exchanged
between a cellular communications device and a mobile switching center (MSC)
of
the data message system illustrated in FIG. 1.
FIG. 3 is a block diagram of an exemplary data reporting system for the data
message system illustrated in FIG. 1.
FIG. 4 is a block diagram of an alternative embodiment of the data reporting
system illustrated in FIG. 1
FIGs. SA, SB, SC, SD and SE, collectively described as FIG. 5, are logical
flow diagrams illustrating the steps for communicating commands and/or data by
sending a set of paging messages in accordance with an exemplary embodiment of
the
present invention.
FIG. 6 is a logical flow chart diagram illustrating the steps for programming
a
remote programmable logic controller by sending a set of paging messages in
accordance with an exemplary embodiment of the present invention.
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FIG. 7 is a logical flow chart diagram illustrating the steps for
reprogramming
a remote programmable logic controller by sending a set of paging messages in
accordance with an exemplary embodiment of the present invention.
FIG. 8 is a logical flow chart diagram illustrating the steps for
communicating
an ON/OFF override command to a programmable logic controller by sending a set
of
paging messages in accordance with an exemplary embodiment of the present
invention.
FIG. 9 is a logical flow chart diagram illustrating the steps for
communicating
a data request to a remote programmable logic controller by sending a set of
paging
messages in accordance with an exemplary embodiment of the present invention.
Detailed Description of the Exemplary Embodiments
The present invention is directed to a system for communicating with a
cellular communications device by sending one or more paging messages,
commonly
described as pages, via a cellular network control channel of a cellular
mobile
radiotelephone (CMR) system and using data of the received pages to control
the
operations of a remote controller. Although a conventional cellular device can
receive and process discrete pages transmitted over a forward overhead control
channel (FOCC) of the cellular network control channel, the present invention
provides the advantage of communicating commands (and data) to a cellular-
compatible device for use in connection with a controller, such as a
programmable
logic controller (PLC) device, that controls a field instrument. This adds a
new
communication function for a device capable of monitoring the cellular network
control channel because selected pages can be received and processed to
achieve
remote control over the operations completed by the controller on behalf of a
controlled instrument. It will be appreciated that the cellular-compatible
device can
be integrated within the assembly of the PLC device or housed in an assembly
separate from the PLC device.
The data communication capacity offered by the present invention supports
the transmission and processing of data and commands or instructions, whereas
a
prior paging mechanism was limited to sending a command instructing a selected
cellular device to register with the CMR system in response to a telephone
call. In
contrast to the discrete page processing conducted by prior cellular devices,
the
present invention uses one or more pages carried by the cellular network
control
channel to form a command and/or data sequence for use by a controller coupled
to
CA 02320012 2004-04-08
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the receiving device. The invention is particularly useful for communicating
and
programming schedule information for the control operations of a PLC coupled
to the cellular-
compatible device.
The present invention is preferably implemented for use with a data message
system that adapts an existing architecture and communications protocols for a
conventional
CMR system to supply an advantageous approach to the communication of data
collected
from one or more remote sites. In this data message system, which is described
in U.S.
Patent Nos. 5,546,444; 5,526,401 and 5,873,043, a cellular communications
device can send
a data message to a mobile switching center (MSC) via the cellular network
control channel.
In addition, the MSC can send commands and/or data in the form of pages to one
or more
cellular communications devices via the cellular network control channel. U.S.
Patent Nos.
5,546,444; 5,526,401 and 5,873,043 are assigned to the assignee of the present
application and
may be referred to for further details.
It will be understood that the communication of messages between the MSC and
1 S a cellular communications device can be conducted by adapting conventional
techniques and
known protocols of a CMR system for data communications. Accordingly, prior to
describing the detailed operation of the data message system, it will be
useful to review the
operation of a typical CMR system.
A CMR system is generally characterized by dividing a radio coverage area into
smaller coverage areas or "cells" using low power transmitters and coverage-
restricted
receivers. As will be known to those skilled in the art, the limited coverage
area allows the
radio channels used in one cell to be reused in another cell. As a mobile
radiotelephone
within one cell moves across the boundary of the cell and into an adjacent
cell, control
circuitry associated with the cells detects that the signal strength of the
mobile radiotelephone
in the just-entered cell is stronger and communications with the mobile
radiotelephone are
"handed-ofF' to the just-entered cell.
A CMR system typically uses a pair of radio frequencies for each radio
channel and each cell. Each cell typically includes at least one signaling
channel,
also referred to as a cellular network control channel or an access channel
and several
voice channels. The control channel is selected or dedicated to receive
requests for
service from mobiles and portables, to page selected mobiles or portables, and
to instruct
the mobiles or portables to tune to a predetermined voice channel where
a conversation may take place. Accordingly, the control channel is normally
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responsible for receiving and transmitting data to control the communication
actions
of the mobile and portable radiotelephones.
The control channel normally comprises a FOCC for communications from
the MSC to a radiotelephone unit and a reverse overhead control channel (RECC)
for
S communications from a radiotelephone unit to the MSC. The FOCC supplies a
multiplexed data stream of message data words, a busy idle signal, and busy
idle bits.
The busy idle bits are useful for supplying an indication to monitoring
radiotelephones about the current status of the RECC. If the RECC is in use by
a
radiotelephone unit, then the RECC is considered to be busy and the busy idle
bit is
set to a binary one value. Alternatively, if the RECC is not in use, then the
RECC is
considered to be idle and the busy idle bit is set to binary zero value.
Mobile
radiotelephones monitor the busy idle bits transmitted by the FOCC and, if the
busy
idle bit is set to a binary one value, then the mobile radiotelephone delays
transmission on the RECC until the busy idle bit is set to a binary zero
value. Thus, a
radiotelephone normally transmits on the control channel during the window of
opportunity that is presented by a transition from the busy state to the idle
state. In
particular, the busy idle bit supplies an instantaneous view of the signaling
activity on
the control channel, and the conventional radiotelephone is responsive to this
instant
snapshot of control channel activity.
The data message and radio channel specifications for U.S. cellular
radiotelephone systems are set forth in Electronic Industries
Association/Telecommunications Industry Association (EIA/TIA) Standard 553,
implemented in accordance with 47 C.F.R. ~ 22, in the Report and Orders
pertaining
to Federal Communications Commission (FCC) Docket No. 79-318. Copies of the
EIA/TIA-553 may be obtained from the Engineering Department of the Electronic
Industries Association at 2001 Pennsylvania Avenue, N.W., Washington, D.C.,
USA
20006.
It is known that when a cellular mobile radiotelephone originates a call, it
transmits a series of data messages to the serving cell. These messages,
commonly
referred to as Call Origination, are defined by EIA/TIA-553. These data
messages
contain the low order seven digits of the unit's telephone number, known as
the
Mobile Identification Number (MII~, the unit's Station Class Mark (SCM), which
identifies functional characteristics of the unit, and the Called Address, or
dialed
telephone number. Cellular system operators typically also require additional
data
words to be transmitted that contain the MIN2, which is the high order three
digits or
CA 02320012 2000-09-18
NPA of the cellular unit's telephone number, and the Electronic Serial Number
(ESN). The MIN is assigned to a particular radiotelephone unit by the cellular
service
provider selected by the subscriber. The MIN typically contains information
unique
to the CMR system operator, for example, the first three digits of the MIN
("XXX")
5 typically correspond to an area code, the next three digits ("XXX")
typically
correspond to a geographic location within the area code; and the final four
digits
("XXXX") identify a particular piece of equipment. Similarly, the ESN is
unique to
each mobile cellular radiotelephone unit, and comprises a format that allows
differentiation as to manufacturer and, in some cases, the model number, date
of
10 manufacture, and the like.
These messages are provided first to the cell, and then through a data link to
a
mobile telephone switching center, otherwise described as a mobile switching
center.
The MSC, also known as a MTSO or a "switch," makes voice connections between
mobile radiotelephones and other telecommunications networks. At the MSC, a
determination is typically made whether the radiotelephone is an authorized
user or
subscriber by looking up the unit's telephone number, serial number, and other
information supplied by the radiotelephone to see if there is an entry in the
MSC's
database corresponding to that particular telephone. An optional function of
an MSC
is to validate that the ESN and MIN received as part of a Call Origination
message are
valid. If the MIN is valid and the radiotelephone is identified as a
subscriber within
the given cellular system, i.e., a "home" unit, the received ESN is compared
to the
MSC's database ESN entry to detect fraud. If these checks succeed, the
cellular call
is then allowed to proceed.
It is also well known that when a mobile radiotelephone first powers up or
first
enters a CMR system when already powered, the unit can identify itself as
actively
present within the system. The radiotelephone identifies itself or "registers"
through a
process known as Autonomous Registration by supplying a data packet similar to
that
of a Call Origination message. The Autonomous Registration signal, also
referred to
as a registration or identification signal, typically comprises data fields
for at least a
mobile telephone number, i.e., the MIN, and an ESN. The original design
attempt of
Autonomous Registration was to improve the efficiency of potential future call
deliveries by keeping the MSC informed of the approximate whereabouts of each
individual radiotelephone unit, and to reduce paging channel load by lessening
the
need to page all cells to find a particular cellular unit. When the MSC is
thus
informed, it can later "page" or attempt to ring the cellular unit only in the
cell or area
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11
that it was last known to be in. Additional cells would be paged only if the
initial
page did not locate the particular radiotelephone. Thus, Autonomous
Registration is
simply a set of messages periodically and autonomously sent from the mobile
radiotelephone to the serving cell at an interval specified in data parameters
previously received from the cell by the cellular unit.
Refernng now to the drawings, in which like numerals indicate like elements
throughout the various figures, FIG. 1 illustrates a data message system 10
operating
within a CMR system 8. Referring to FIG. 1, the data message system 10
supports
the collection and communication of data to a central data collection site by
reporting
systems associated with numerous data sources. By operating within the
environment
of the CMR system 8, which is well adapted for portable or mobile
communications,
the data message system 10 takes advantage of an existing wide area
communications
network and avoids the expense of communicating with each remote data site via
a
dedicated conventional telephone facility or conventional two-way radios.
Numerous
communications applications are available for the data message system 10,
including
communicating data collected from a wide variety of data sources, such as
utility
meters, community antenna television (CATV) pay-per-view (PPV) terminals,
equipment operating at isolated sites, and security alarm systems.
The data message system 10 adapts the existing environment of a CMR
system to communicate data from one or more remote sites to a central
location.
However, to conserve the use of voice channels of the CMR system for
conventional
telephone conversations, the data message system 10 uses the cellular network
control
channel of the CMR system for data communications. This permits conservation
of
the valuable frequency spectrum dedicated to the voice channels of the typical
CMR
system.
A typical CMR system includes a geographic radio service area, such as
indicated by the cell 12, of which a plurality of cells are typically provided
in a typical
cellular service operator's system. The cell 12 is served by a broadcast
antenna 14 to
permit communications between cellular mobile radiotelephones operating within
the
cell 12 and a cell control 16. A mobile telephone switching office, such as
the MSC
24, can communicate with the cell 12 either by dedicated telephone facilities
(not
shown) or, more frequently, by a cell-to-mobile switching center data link 22
between
the cell control 16 and the MSC 24. At least a portion of the data link 22 is
typically
supported by a wireless communications link, such as the microwave link 20,
located
between the cell 12 and the MSC 24.
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12
It is well known to those skilled in the art that the conventional CMR system
comprises at least one mobile telephone switch coupled to an appropriate array
of
more or less identically equipped cell sites 12. The MSC 24 normally couples
telephone conversations involving mobile radiotelephones operating in the cell
12 to
the public switched telephone network (PSTN) 26 through telephone facilities
28.
The data message system 10 includes a set of data reporting devices 29, each
comprising at least one controller 32' and a cellular communications device
34. A
cellular communications device 34 can communicate with the MSC 24 via a
control
channel of the CMR system. The controller 32', which is connected to one or
more
instruments or controllable items via a signal path 31', is typically
implemented as a
PLC for controlling the operations of a field instrument or a controllable
item. The
cellular communications device 34, which is connected to the controller 32'
via a
signal path 33', can communicate with the MSC 24 via a cellular network
control
channel 38 and accept page messages containing commands and/or data for use by
the
controller 32'. In addition, the cellular communications device 34 can
transmit data
messages, typically formatted as a Call Origination message or an Autonomous
Registration signal, to the MSC 24 via the cellular network control channel
38.
In the alternative, the data reporting device 29 can include a monitor 32,
shown in FIG. 3, which is operative to collect selected data from one or more
remote
data sources 30. The monitor 32 obtains and records selected data directed to
the
operation or performance characteristics of each data source 30. In turn, the
cellular
communications device 34, which is connected to the corresponding monitor 32
via a
signal path 33, prepares a data packet containing the selected data and
transmits the
packet as a data message. The selected data represents actual data acquired by
the
monitor 32 in response to monitoring the operation or performance of the data
source
30. Alternatively, the selected data can represent predetermined data or a
preprogrammed message that is associated with the detection of a certain event
by the
monitor 32 for the data source 30.
The MSC 24 can communicate with the cellular communication devices 34
via the cellular network control channel 38, which is formed by the
combination of
the data link 22 and a cellular communications link 36 between the broadcast
antenna
14 and the cellular communications device 34. This combination of
communications
links is collectively referred to as the control channel. It is well known
that a cellular
network control channel for a conventional CMR system comprises two radio
channels that are commonly described as a FOCC 38a and a RECC 38b. The FOCC
CA 02320012 2000-09-18
13
38a is used for communications initiated by the MSC to a radiotelephone unit,
such as
the cellular communications device 34. In contrast, the RECC 38b is used for
communications from a radiotelephone unit to the MSC 24. The communications
operations of the data message system also use this convention for
communications
between the MSC 24 and the cellular communications device 34. 1n particular,
the
control channel 38 comprises two separate data communications paths, an FOCC
38a
for communications initiated by the MSC 24 and an RECC 38b for communications
initiated by the cellular communications devices 34 (or mobile radiotelephones
operating within the cell). Accordingly, the cellular communications device 34
transmits data messages via the RECC 38b, whereas the MSC 24 transmits page
messages, typically comprising commands and/or data, via the FOCC 38a.
In this manner, the MSC 24 can transmit command and data to each of the
cellular communication devices operating within the coverage areas of an array
of
cells for the CMR system 8. Likewise, the MSC 24 can receive data messages
from
each of those cellular communications devices 34. Although the data messages
contain selected data rather than the parameters normally contained in an
actual
radiotelephone control information, the MSC 24 will operate upon the data
messages
as if they were transmitted by a conventional radiotelephone operating within
the cell
because the data messages are formatted to appear as a registration signal or
a call
origination signal generated by a radiotelephone unit.
The MSC 24, in response to a data message transmitted by a data reporting
device, can conduct one or more of the following operations: store the data
message
for processing at a later date, process the selected data supplied by the data
message,
or forward the data message to a data collection system 40 via a first
communications
link 42. The data collection system 40, which is connected to a memory storage
device 44, collects the selected data by storing the received data messages
within the
memory storage device 44. Similar to the MSC 24, the data collection system 40
also
can process the selected data to obtain further information concerning the
operation or
performance of the data sources 30. Alternatively, the data collection system
40
sends the data message to a data processing system 46 via a second
communications
link 48. The data processing system 46 is typically remotely located from the
data
collection system 40 and facilitates convenient processing of the selected
data at a
central site. The second communications link 48 is typically implemented by a
conventional telephone facility, a dedicated data link, or by a wireless
3 5 communications link.
CA 02320012 2000-09-18
14
Referring still to FIG. 1, in response to the transmission of a data message
by a
cellular communications device 34, the MSC 24 typically makes a determination
whether the cellular communications device 34 that transmitted the data
message is an
authorized user or subscriber of the services offered by the cellular system 8
or
another system. As shown in FIG. 2 and described below with respect to the
data
message format, the data message preferably includes certain information that
identifies the cellular communications device 34 as a radiotelephone that
normally
operates within a certain remote or foreign cellular system. Based upon this
information, the MSC 24 decides that the cellular communications device 34 is
a
"roamer" because it appears to be affiliated with the cellular service offered
by
another cellular system, which, in this case, is the remote cellular system.
In
particular, the MSC 24 maintains a list or database that identifies the
certain
information in the data message as belonging to a particular cellular system
and, by
checking this database, determines whether the cellular communications device
34 is
a subscriber or a roamer. Thus, it will be understood that the MSC 24
interprets the
data message as a transmission from a roaming mobile radiotelephone operating
within the CMR system 8.
The remote cellular system identified by the data message is not an actual
operating cellular system for supporting telephone conversations, but rather
is
dedicated to data collection applications and is represented by the data
collection
system 40. In recognition that the cellular communications device 34 is
actually
associated with the remote cellular system, the MSC 24 forwards the data
message to
the data collection system 40 via the first communications link 42. The data
collection system 40 responds by sending to the MSC 24 a message which
confirms
that the roamer associated with the data message is a valid or authorized user
of the
remote cellular system. The cellular communications device 34 is thereafter
added as
a registered radiotelephone to a database of registered roamers at the MSC 24.
The data collection system 40 has now received the data message containing
selected data. Accordingly, the data collection system 40 transmits a message
to the
MSC 24 that instructs the MSC to delete the cellular communications device 34
from
its list of registered roamers. It will be understood that the MSC 24 would
normally
receive this type of message when a roaming radiotelephone has moved to
another
cellular system and subsequently registered for operation on that other
system. Thus,
the database of the MSC 24 is no longer required to maintain the registration
CA 02320012 2000-09-18
information concerning the cellular communications device 34 after
transferring the
data message to the data collection system 40.
Alternatively, the MSC 24 clears its database of such registration information
upon the expiration of a certain time interval. The data collections system 40
can
5 respond to the data message by transmitting a message which confirms that
the
roamer is a valid user and further instructs the MSC 24 to delete the
registration entry
upon the expiration of the certain time interval. As a separate option, the
MSC 24 can
automatically delete a registration entry from the MSC database upon
expiration of a
certain time period without any instruction from the data collection system
40. In this
10 manner, the data collection system 40 is not required to send yet another
message to
the MSC 24 after the data collection system 40 confirms that the cellular
communications device 34 represents a valid user.
The MSC 24 and the data collection system 40 are preferably compatible with
the EIAITIA Interim Standard 41 (IS-41 standard). The IS-41 standard defines a
15 communications protocol for communications between two cellular systems.
The IS-
41 standard allows cellular calls to be handed-off between dissimilar cellular
systems,
not unlike the way that calls are handed-off between cells of a single CMR
system. In
addition, the IS-41 standard permits call deliveries and a communications
exchange
for verifying whether a cellular caller is a valid cellular service
subscriber. In this
manner, the MSC 24 hands-off or forwards the data message to the data
collection
system 40 via the first communications link 42, which is preferably
implemented as
an IS-41-compatible network. In response, the data collection system sends a
user
validation message via the link 42 to confirm that the source of the data
message,
specifically a cellular communications device 34, is a valid cellular source.
In particular, the data collection system 40 recognizes that the received data
message contains selected data which has been transmitted by a cellular
communications device 34. Accordingly, the data collection system 40 processes
the
received data message and compares the predetermined identifying
characteristic in
its data message to a list of such characteristics in its database. This
database
preferably contains an entry of the predetermined identifying characteristic
for each of
the known cellular communications devices 34 and corresponding data that
identifies
the associated device as a valid cellular source. Upon obtaining a positive
match, the
data collection system 40 preferably responds to the received data message by
sending
to the MSC 24 the verification message. It will be appreciated that the data
collection
CA 02320012 2000-09-18
16
system 40 also can forward to the MSC 24 a message confirming the absence of a
valid entry for the cellular communications device 34 in response to a
negative match.
This validation message can also include a profile of communications services
that are authorized for use by the particular cellular source. For example,
this user
profile typically defines the operations limitations for the cellular source,
including
access to long distance services, the capability for the source to only
originate (and
not receive) calls via the cellular system, etc. The user profile information
can
contain an instruction that commands the MSC 24 to delete from its database
the
registration entry for the particular cellular communications device after the
expiration of a certain time period. This allows the MSC 24 to clear from its
database
entries for cellular communications devices 34 that have communicated their
data
message via the cellular system 8 by registering with the MSC 24 because such
devices no longer require the continued communications support of the MSC 24.
The data collection system 40 can store the selected data supplied by the
received data message within the memory storage device 44, can process the
selected
data and store the resultant data, or can forward the selected data to the
data
processing system 46 for processing. Prior to sending the selected data to the
data
processing system 46, the data collection system 40 first converts the data
message to
an acceptable communications protocol for conveying the data message to the
data
processing system 46. This step is necessary prior to communication with the
data
processing system 46 because, unlike the MSC 24 and the data collection system
40,
neither the data processing system 46 nor the second communications link 48
are
compatible with the IS-41 standard.
Although the MSC 24 is typically programmed to treat the cellular
communications devices 34 as roamers associated with a foreign cellular
system, it
will be appreciated that the database of the MSC 24 also can be programmed to
contain entries for the predetermined identifying characteristics of those
cellular
communications devices 34 operating within the cells of the cellular system 8.
Upon
receiving a data message via the control channel 38 from such a device 34, an
MSC
24 containing such database entries will identify the transmitting cellular
communications device 34 as a "home" unit rather than as a roamer because the
MSC
database contains an entry that corresponds to the predetermined identifying
characteristic supplied by the message. Thus, the MSC 24 registers the
firansmitting
cellular communications device 34 as a home unit of the cellular system 8.
This
avoids the additional requirement of contacting a foreign cellular system,
such as the
CA 02320012 2000-09-18
17
data collection system 40, to inquire whether this cellular source is a valid
user or
subscriber of cellular services.
However, to initiate the necessary transfer of the information in the data
message to the data collection system 40, the MSC 24 for this embodiment is
adapted
to recognize that data messages should still be forwarded to the data
collection system
40. Specifically, based upon a portion of the predetermined identifying
characteristic
that is uniquely associated with the data collection system 40, the MSC 24
locates an
entry in its database that commands the switch to send all messages containing
such a
characteristic to the data collection system 40. Accordingly, the MSC 24
thereafter
forwards the data message via the first communications link 42 to the data
collection
system 40.
The data collection system 40 can be implemented by a computer. One
embodiment for the data collection system 40 is the computer of a service
circuit
node. Certain manufacturers of switches, such as the MSC 24, also offer
devices for
implementing communications with the data collection system 40, including the
Motorola EMX switch and other vendor proprietary switches. The cellular system
8
is preferably implemented as an AMPS or a DAMPS cellular system. However, it
will be appreciated that the cellular system 8 also can be compatible with
alternative
cellular systems, such as the GSM system, implementing a control channel for
mobile-to-cell communications.
It will be appreciated that the CMR system 8 includes an array of cells, such
as
the cell 12, and that a set of reporting systems 29, each formed by the
monitor 32 and
the cellular communications device 34, are typically located in a cell. For
each data
source 30 within the cell 12, the monitor 32 (controller 32') and the cellular
communications device 34 are preferably located proximate to the data source
30
(instrument 30') to minimize the lengths of the signal paths. To facilitate
economical
installation of the reporting device, the monitor 32 (the controller 32') and
the cellular
communications device 34 can be combined within the same housing and this
housing
can be installed either adjacent to or as an integral part of the data source
30
(instrument 30'). For an installation proximate to the data source 30 or a
controllable
instrument 30', the signal paths are preferably formed by hard-wired
connections
between the connected devices. Nevertheless, it will be appreciated that the
signal
paths also can be implemented as either infrared communications links or
wireless
communications links.
CA 02320012 2000-09-18
18
The data collection system 40 can be located proximate to or as an integral
part of the MSC 24, in which case the first communication link 42 preferably
forms a
hard-wired connection between the devices. However, the data collection system
40
also can be positioned at a remote site. For this remote installation, the
first
communications link 42 can be implemented as a wireless communications system,
such as a microwave system, or as a dedicated data line, such as a
conventional
telephone facility. For the convenience of the party that is sponsoring the
collection
of a particular type of data, the data processing system 46 is typically
located at
another remote site that is typically proximate to the sponsoring party.
FIG. 2 is a diagram that shows the format for the data message that is
communicated by the data message system 10. Refernng now to FIGS. 1 and 2, a
data record 50 for the data message contains both a data field 54 for the
selected data
acquired from the remote data source 30 and a data field 52 for a
predetermined
identifying characteristic which uniquely identifies the cellular
communications
1 S device 34 that initiates the transmission of the data message. To take
advantage of the
existing architecture of a CMR system 8, the format for the data message
preferably is
identical to the message format (or data record) for an identification signal
that is
transmitted by a cellular radiotelephone when it first identifies itself to a
CMR
system, such as the CMR system 8.
By using the data message format associated with an Autonomous
Registration signal, the cellular communications device 34 "registers" with
the MSC
24 by sending a data message that appears to contain a mobile telephone number
and
an ESN. Although it is not intended for the cellular communications device 34
to
place a conventional voiced-based cellular telephone call, the cellular
communications device 34 nevertheless registers for operation with the MSC 24,
thereby enabling the communication of the selected data from the field.
Alternatively, the format for the data message can be identical to the format
or
data record for a Call Origination signal that is transmitted by a cellular
radiotelephone when it originates a telephone call. Similar to the format for
a
registration signal, the cellular communications device 34 can appear to
originate a
call by sending a data message formatted as a Call Origination signal to the
MSC 24.
Although the MSC 24 processes the data message as if it contained a mobile
telephone number and an ESN, the data message is actually used to communicate
selected data placed within one or more data fills normally reserved for the
mobile
telephone number and the ESN. Although the Call Origination signal format can
be
CA 02320012 2000-09-18
19
used to transport data from the cellular communications device to the MSC, it
will be
understood that the data message system 10 is employing this format for data
communication rather than for call origination.
As shown in the data record SO in FIG. 2, the standard message format for a
registration signal (call origination) has been adapted by the data message to
permit
the identification of the particular transmitting cellular communications
device 34 and
the communication of the selected data. In particular, the data field 52 for
the
predetermined identifying characteristic corresponds to at least a portion of
a mobile
telephone number or MIN assigned to the cellular communications device 34.
Thus,
the predetermined identifying characteristic is substituted within the data
field
normally reserved for the MIN in an identification signal. This predetermined
identifying characteristic can belong to a set of unassigned mobile telephone
numbers.
Alternatively, the predetermined identifying characteristic assigned to each
cellular
communications device 34 can be a conventional telephone number or a set of 10
digits. The predetermined identifying characteristic permits the
identification of the
source of the data by uniquely identifying the cellular communications device
34.
The predetermined identifying characteristic also supplies information used by
the
MSC 24 to recognize that the data message containing this predetermined
identifying
characteristic is associated with the data collection system 40.
Furthermore, the data field 54 in the data message for remote data corresponds
to the location within the data record for the ESN. Those skilled in the art
will
appreciate that the ESN is 32 bits long and includes 8 bits for a manufacturer
code.
For cellular systems that do not review or screen ESNs based upon the
manufacturer
code segment, it is possible to manipulate the data field normally filled by
an ESN to
supply a data message having a data field 54 containing 32 bits of selected
data.
However, if the cellular system uses the manufacturer code segment of the ESN,
the
selected data within the data field 54 comprises a length defined by the
remaining 24
bits of the ESN. For most applications, it will not be necessary to manipulate
the
manufacturer's code segment of the ESN because a data message having 24 bits
of
selected data (and, as required, 8 bits of the manufacturer code segment for a
conventional ESN) should be sufficient to supply relevant data.
FIG. 3 is a block diagram that illustrates the components of an exemplary
reporting system 29 operable for data monitoring and collection applications,
namely
the monitor 32 and the cellular communications device 34. Referring now to
FIGS. 1
and 3, the monitor 32 includes a recorder 60, a memory 62, and one or more
sensors
CA 02320012 2000-09-18
64. The recorder 60, which is connected to the data source 30 via the signal
path 31,
uses the sensors 64 to detect certain operating or performance characteristics
of the
data source 30. The detected characteristics represent selected data that are
preferably
stored within the memory storage device 62. The memory 62 is preferably random
5 access memory (RAM). However, it will be understood that the memory 62 also
can
be implemented by other types of data storage devices, including flash memory,
a
flexible diskette, a computer hard disk or an optical disk.
It will be appreciated that the signal path 31 represents one or more signal
channels for transferring the selected data to the recorder 60 and,
furthermore, that the
10 recorder 60 can be implemented as either a single or mufti-channel
recording device.
Each signal channel normally would be associated with a different operating or
performance characteristic for the data source 30.
For certain applications, the recorder 60 records selected data from the data
source 30 for a predetermined time period. A clock 66 connected to the
recorder 60
15 supplies timing data to the recorder 60, thereby enabling the recorder 60
to add a time
tag to the selected data. The time tag indicates the relative time for the
start of each
predetermined time period of recording operations. Assuming that the
predetermined
time period is a known value, the addition of the time tag data permits the
calculation
of the start and completion times for each data reporting operation.
Correlation of the
20 data collection time to the selected data is desirable for certain
processing operations.
The clock 66 can be implemented as a conventional counter supplied by a
hardware
device or as a software routine executed by a microprocessor.
The cellular communications device 34 includes at least a data receiver 70, a
cellular transmitter 72, and a controller 74. The data receiver 70, which is
connected
to the recorder 60 via the signal path 33, receives the selected data obtained
from the
data source 30 by the monitor 32. The controller 74, which is connected to the
data
receiver 70 and the cellular transmitter 72, controls the respective
operations of the
data receiver 70 and the cellular transmitter 72. The controller 74 is
preferably a
microprocessor-based control system that can be programmed to conduct control
operations in a manner known to the art.
In response to the selected data, the controller 74 prepares a data packet
containing the predetermined identifying characteristic associated with the
cellular
transmitter 72 and the selected data collected from the data source 30. The
cellular
transmitter 72 responds to the data packet by transmitting a corresponding
data
message via the control channel 38 of the CMR system 8. Specifically, the
cellular
CA 02320012 2000-09-18
21
transmitter 72 uses the RECC of the control channel 38 to send data messages
to the
MSC 24. Although the cellular transmitter 72 can be implemented as a
conventional
transmitter for a radiotelephone unit, the preferred cellular transmitter 72
uses only
the data radio channels of the CMR system 8 for transmission of data messages.
The cellular communications device 34 further includes a memory storage
device 76 connected via a bi-directional data path to the controller 74. The
selected
data received by the data receiver 70 can be stored in the memory storage
device 76
prior to the transmission of a data message by the cellular transmitter 72.
Although
the memory storage device 76 is shown as a separate memory from the memory
storage device 62, it will be appreciated that the memory storage devices 62
and 76
can be implemented as a single memory which is accessible by both the recorder
60
and the controller 74. The memory storage device 76 can include one or more
masks,
as shown in FIG. 3, for storing identifiers assigned to the cellular
communications
device 34. As will be described in more detail below with respect to FIG. 5,
each
specific identifier is typically numeric data formatted as a cellular
telephony MIN.
The MSC 24 can issue a page containing a specific identifier assigned to a
cellular
communications device 34 to initiate a communication via the FOCC with that
particular device. Those skilled in the art will appreciate that the masks in
the
memory 76 can store other forms of data, including characteristics for a
variety of
communication operations supported by the cellular communications device 34.
To connect the cellular communications device to another device, such as a
monitor 32, a signal path is connected between both devices, as illustrated by
signal
path 33 in FIG. 3. The signal path 33 can be implemented as a conventional
data
communication link compatible with known protocols, including the RS-232
serial
protocol. To support an exchange of data between both devices, the signal path
33 is
preferably a bi-directional signal path. In addition to the external port
connected to
the signal path 33, the cellular communications device 34 can include other
external
data ports. These additional data ports can be connected directly to the
controller 74,
a data receiver and/or transmitter, or a memory storage device. For example,
an
external port can be used to program the cellular communications device 34
prior to
field operations. Alternatively, an external port can be used to output data
from the
cellular communications device 34 to another device. It will be understood
that the
cellular communications device 34 is not limited to the single external port
shown in
FIG. 3, and can include additional external ports as required to support
various
applications.
CA 02320012 2000-09-18
22
To receive communications from the MSC 24 via the FOCC of the cellular
network control channel 38, the cellular communications device 34 also
includes a
cellular receiver 78. The cellular receiver 78, which is connected to the
controller 74,
can be implemented as the cellular receiver for a conventional radiotelephone.
However, similar to the cellular transmitter 72, the preferred cellular
receiver 78
operates to receive information primarily via the data radio channels rather
than the
voice radio channels of the CMR system.
The cellular transmitter 78 typically transmits the data message only when the
control channel is available for clear use by the cellular communications
device 34.
This form of data queuing minimizes the possibility that the operation of
numerous
cellular communications devices 34 within the cell 12 will interfere with
normal
telephone conversations involving the operating radiotelephones within the
cell.
Nevertheless, it will be appreciated that the cellular transmitter 78 also can
transmit
the data message without first checking the availability of the control
channel 38.
Alternatively, the cellular communications device 34 can be programmed to
transmit the data message during a certain time interval, such as during the
early
morning hours between midnight and 6 AM, when control signal traffic is
normally at
a minimal level. To permit this type of automated transmission operation, the
cellular
communications device 34 includes a clock 82 connected to the controller 74.
The
clock 82 outputs a clock signal in response to expiration of a time interval.
In
response to the clock signal, the controller 74 initiates a data message
transmission by
the cellular transmitter 72. In this manner, selected data is transmitted
during a
known time interval from one of the reporting devices within the cell 12 to a
central
location.
The clock 82 preferably outputs the clock signal during the time period when
use of the control channel 38 is at a reduced level, thereby minimizing the
possibility
that the cellular communications device 34 will interfere with the normal
communications operations of the CMR system 8. In particular, the time
interval is
preferably selected with advance knowledge of the reduced activity periods for
conventional telephone conversation traffic on the CMR system 8 to ensure that
data
message transmissions by the various cellular communications devices 34 in the
cell
12 are conducted on a noninterference basis with voice call processing
messages
transmitted to and from the radiotelephones operating in the cell. The clock
82 can be
implemented as either a hardware counter or as a software counter implemented
by
coded instructions executed by the controller 74.
CA 02320012 2000-09-18
23
A data transmission by the cellular communications device 34 also can be
initiated in response to a status signal output via the signal path 33 by the
monitor 32.
This status signal causes the cellular communications device 34 to transmit
the stored
selected data via the RECC of the control channel 38. The monitor 32 typically
outputs the status signal in response to the completion of a data recording
event. For
example, in a typical vending equipment application, the monitor 32 can output
the
status signal in response to an alarm event, such as the detection of a
maintenance
service requirement. Alternatively, for an utility load management
application, the
monitor 32 can output the status signal in response to detection of possible
tampering
of the utility's load control device. Those skilled in the art will appreciate
that the
generation of the status signal is event-driven and that the applications for
the data
message system 10 will determine those events.
It will be appreciated that the process of outputting a clock signal or a
status
signal to initiate a data message transmission by the cellular communications
device
34 is similar to an Autonomous Registration operation that is conducted by
certain
known radiotelephone units. For an Autonomous Registration, the radiotelephone
automatically identifies itself to the cellular system by initiating its own
registration
operation. Likewise, for the described embodiments, the cellular
communications
device 34 responds to the clock signal or the status signal by sending a data
message
having a message format that is representative of the data record for a
registration
signal (Call Origination signal) of a radiotelephone unit. In turn, the MSC 24
receives
the data message via the control channel 38 and subsequently operates upon the
data
message as if it were a registration signal (call origination signal)
transmitted by a
conventional radiotelephone unit.
It is well recognized that a cellular network control channel, such as the
control channel 38, is a two-way communications path between the MSC 24 and
the
radiotelephone devices operating in the cell 12. Specifically, an MSC 24 can
send a
paging message or "page" to one or more radiotelephone devices operating
within the
coverage area defined by the cell 12 of the CMR system 8. In contrast to
conventional radiopaging systems, this page message is transmitted via the
FOCC of
the CMR system rather than via a radiopaging terminal. For CMR systems, this
page
message is typically used to notify a cellular mobile radiotelephone device
that an
incoming telephone call is pending, thereby prompting the cellular device to
register
with the CMR system.
CA 02320012 2000-09-18
24
The receiver 78 can receive pages from the MSC 24 via the FOCC of the
control channel 38. For example, the MSC 24 can output command signals, which
are formatted as pages, via the control channel 38 to initiate certain
operations or to
control certain functions of one or more of the cellular communications
devices 34
within the cell 12. The receiver 78 can monitor the control channel 38 for
finite time
periods defined by a clock signal output by the clock 82. For example, the
clock 82
can operate as a timer defining a time period for a monitoring operation
completed by
the receiver 78. The cellular communications device 34 can respond to a
command
signal by conducting a particular operation or by controlling a certain
function
associated with the command signal.
The command signals typically include address data and each cellular
communications device 34 responds to a command signal containing its
predetermined address data. This allows the MSC 24 to communicate with one or
more of certain cellular communications devices 34. By proper use of the
addressing
1 S operation, it is possible for the MSC 24 to remotely control the
operations or
functions of a subset of the cellular communications devices 34 that is
selected from
the overall group of devices 34 within the cell 12.
The command signal is preferably a 10 digit number that represents a
conventional mobile telephone number. At least a portion of this telephone
number
can be assigned as an identifier for a corresponding cellular communications
device
34. The remaining portion (if any) of the 10-digit telephone number can
represent a
command or data for a particular operation or function. In this manner, a
cellular
communications device 34 can be programmed to respond only to a command signal
containing its address data and to conduct the particular operation or
function
identified by the command.
By transmitting command signals to the cellular communications devices 34,
the MSC 24 can remotely control various operations of the cellular
communications
devices 34 or can remotely define various programmable operating parameters of
the
devices 34. For example, in response to a selected command signal, the
cellular
communications device 34 "registers" with the MSC 24 by transmitting a data
message to the MSC 24. It will be appreciated that this command signal is
similar to
a conventional Locate Request signal generated by a CMR system, such as the
AT&T
Autoplex System, and requests registration of a selected radiotelephone unit.
By use
of this command signal, a selected cellular communications device 34 can be
polled at
CA 02320012 2000-09-18
any time by the MSC 24 to initiate the transmission of a data message
containing the
desired selected data.
For another representative example, the time interval for the clock 82 can be
modified or otherwise replaced with a substitute time period in response to a
S command signal. The cellular communications device 34 also can instruct the
monitor 32 to initiate a recording of data from the remote data source 30 in
response
to yet another command signal. In particular, the controller 74 responds to
the
detection of the command signal by the cellular receiver 78 and outputs an
instruction
signal to the recorder 60 to prompt the data reporting operation.
10 The opportunity for placing a command or data, or a combination of a
command and data, within the conventional format of a paging message is
limited by
the defined character length of the paging message, typically the 10-digit
telephone
number or MIN. For relatively short data lengths, the transmission of a single
independent page message from an MSC to a cellular device in the manner known
to
15 the art is useful to support limited communications. This fixed data length
for a page
message is satisfactory for the paging communication task of conventional CMR
system operations, namely, the polling of one or more mobile radiotelephones
within
the coverage area of the CMR system. This polling technique only requires the
transmission of a single discrete page message to prompt a response from a
mobile
20 radiotelephone unit that receives the page. Prior to the present invention,
there was no
readily available mechanism for exploiting the paging message mechanism to
transfer
an expanded data set.
As described in U.S. Patent No. 5,873,043, a data message system can be
constructed to communicate multiple page messages or pages via the cellular
network
25 control channel to a cellular-compatible receiving device. The data
obtained from
each received page can be combined to form an aggregate message comprising a
data
sequence. An exemplary data reporting system 29 can be constructed to support
the
transfer of commands and/or data via pages carried via the FOCC for use by a
controller, such as a programmable logic controller device. Turning now to
FIG. 4,
this embodiment of the data reporting system 29 includes a controller 32' and
a
cellular communications device 34. The controller 32' comprises a processor
94; a
memory 96, an input/output 98 and a communication port 100. The processor 94
controls the operations of the controller 32' based on instructions and data
maintained
in the memory 96. The memory 96 typically contains a control schedule in the
form
of a look-up table that defines the control operations of the controller 32'
for one or
CA 02320012 2000-09-18
26
more control applications associated with the controllable instrument 30'. The
input/output 98 support communications between the processor 94 and the
controllable instrument 30'. The communication port 100, typically a serial
port,
provides a communications path between the processor 94 and the cellular
communications device 34. The controller 32' is coupled to the controllable
instrument 30' via a signal path 31' and to the cellular communications device
34 via
a signal path 33'. The controller 32' can be implemented by a conventional PLC
capable of receiving instructions and data from the cellular communications
device
34. The cellular communications device 34 can receive this content from the
MSC 24
in the form of paging messages via the cellular network control channel 38.
An exemplary format for a page message capable of communicating a
command and/or data to a cellular communications device is described in U.S.
Patent
No. 5,873,043. For an exemplary embodiment of the data message system 10, it
will
be appreciated that command and/or data digits can be encoded within a series
of
pages transmitted by the MSC 24 over the FOCC. For example, the Least
Significant
Digit (LSD) of a MIN in a page can be used to indicate an associated action to
take on
the FOCC DATA. This format requires a 1K block of MINs, for example, OXX-100-
0000 to OXX-100-0999. Five decimal digits of data can be encoded into two data
pages. Each of the data digits are encoded according to Table 1, below, which
is
zero-based right to left, but stored in the FOCC page left to right.
Table 1
Data digits positions are numbered right to left, 0-
based
14 13 12 I1 10 I
Table 2 describes the relationship between the LSB of a MIN and the digits of
FOCC
DATA, including the function corresponding to that data.
CA 02320012 2000-09-18
27
Table 2
MIN Digits of FOCC Function
LSD DATA
0,1 0,1 Add 0 to LSD
of
Second Page
in
Sequence of
Two
Data Pages
2,3 0,1 Add 1 to LSD
of
Second Page
in
Sequence of
Two
Pages
4,5 2,3,4 Data
6,7 0,1 Single Data
Page
8,9 Reserved for Reserved for
future future
use use
FIGs. SA, SB, SC, SD, and SE, collectively described as FIG. 5, are logical
flow chart diagrams illustrating a computer-implemented process for
communicating
programming information to a controller coupled to a cellular communications
device
in a CMR system in accordance with an exemplary embodiment of the present
invention. Turning first to FIG. SA, an exemplary programming process 500 is
initiated at the START step 502 and proceeds to a monitoring step 504. In step
504, a
communications device, such as the cellular communications device 34, monitors
the
cellular network control channel for page messages issued by the MSC of the
CMR
system. For example, the cellular communications device can monitor the FOCC
for
one or more target pages containing a specific identifier assigned to that
communications device. In the event that the cellular communications device
receives a proper sequence of target pages containing a matching specific
identifier,
the communications device can respond by initiating a communications activity,
such
as a monitoring operation for a data page carrying programming content.
In decision step 506, an inquiry is conducted to determine whether the
cellular
communications device has received a target page with a specific identifier
matching
one assigned to the device. If the response to this inquiry is positive, the
"YES"
CA 02320012 2000-09-18
28
branch is followed to step 508. A negative response to this inquiry results in
the
process following the "NO" branch from step 506 to step 518.
In step 508, a determination is made whether a prime timer at the cellular
communications device is active. If the prime timer is not active, the "NO"
branch is
followed to step S 10 and the timer is activated. Otherwise, the "YES" branch
is
followed from step 508 to step 512 and the prime timer is stopped. For the
exemplary
process 500, the prime timer completes a timing operation for a period of 60
seconds
upon activation unless interrupted during that time period. For example, the
prime
timer can be intemtpted in step 512 in response to receiving a second target
page
within the time period of the prime timer. In contrast, the prime timer will
be
activated in step S 10 in response to receipt by the cellular communications
device of a
first target page in a sequence of a pair of target pages.
In step S 14, a separate timer, the ARM timer, is started and a predetermined
time period, typically 60 seconds, is begun. In step 516, the process returns
to the
START step 502 to initiate continued monitoring operations by the cellular
communications device.
If a target page is not received in step 506, an inquiry is conducted in
decision
step S 18 to determine whether the cellular communications device has received
a data
page. If the response to this inquiry is negative, the "NO" branch is followed
from
step 518 to step 504 to continue monitoring operations. Otherwise, the "YES"
branch
is followed from decision step 518 to step 520. A determination is made in
step 520
whether the ARM timer is active. If so, the cellular communications device has
received a pair of target pages, each having a matching identifier, during the
time
period of the prime timer. The process proceeds to step 522 based upon a
positive
response to the inquiry in step 520. If, on the other hand, the ARM timer is
not active,
the process returns to step 504 to continue monitoring operations by the
cellular
communications device.
If the ARM timer is active, the cellular communications device is monitoring
the FOCC for one or more data messages transmitted by the MSC of the CMR
system. In step 522, a determination is made whether the received page
represents a
first data page in a sequence of data pages to be received by the cellular
communications device. For the exemplary process, the first data page is
designated
by the placement of a 0, 1, 2, or 3 in the minimum LSD of the MIN structure of
the
page message. If the received page is the first data message, the "YES" branch
is
CA 02320012 2000-09-18
29
followed from step 522 to step 524 to process the first data message.
Otherwise, the
"NO" branch is followed from step 522 to step 526.
FIG SB is a logical flowchart diagram illustrating the sequence of steps
completed by a exemplary process for processing a first data page. Turning
briefly to
FIG. SB, the first data page, shown as "Data Page 1" in step 524, is processed
by the
cellular communications device. In an exemplary process 524, the data field of
the
first data page is extracted and the data is stored as data digits 0-1 by the
cellular
communications device. These data digits can be stored in big-endian order
within
local memory of the device. In step 542, a receive flag designated as the
"Rxl" flag
is set. The ARM timer is reset in step 544. The exemplary process of task 524
is
completed in step 546 and the process returns to the START step 502 shown in
FIG.
SA.
In step 526, a determination is made whether the received page represents a
second data page in a sequence of pages received by the cellular
communications
1 S device within a time period. For the exemplary process, the second data
page in a
sequence of a pair of pages is designated by the placement of a 4 or S in the
minimum
LSD of the MIN structure of the page message. If the response to this inquiry
in step
526 is positive, the "YES" branch is followed to step 528 to initiate
processing of the
second data page. Otherwise, the "NO" branch is followed from step 526 to step
530.
FIG. SC is a logical flow chart diagram illustrating the sequence of steps
completed by an exemplary process for processing a second data page,
alternatively
described in FIG. SC as "Data Page 2." Turning now briefly to FIG. SC, the
exemplary process at task 528 is initiated by extracting the data field of the
second
data page and storing the extracted as data digits 2 and 3 in local storage at
the
cellular communications device. Data digits 2 and 3 are preferably stored in
big-
endian order. In step 552, an inquiry is conducted to determine whether the
Rxl flag
is set. The Rxl flag is set only if the cellular communications device has
already
received the first data page in a sequence of a pair of data pages. If the
response to
this inquiry is negative, the "NO" branch is followed from step 552 to the
EXIT step
534. If the Rxl flag is set in step 552, the "YES" branch is followed to step
556 and
all timers and flags are cleared at the cellular communications device. The
timers and
flags are cleared because the data sequence has been collected from the
expected pair
of data pages, thereby completing the data collection task for this page
sequence.
In step 558, the cellular communications device can send an acknowledgement
signal to confirm receipt of the data carried by the received data pages. The
CA 02320012 2000-09-18
acknowledgement signal is preferably formatted as an Autonomous Registration
signal in the form of AAAAdddd. An Acknowledge Pattern is represented by
"AAAA (hex)", whereas received data is represented by the "dddd" pattern. The
cellular communications device sends the acknowledgement signal via the RECC
to
5 the MSC of the CMR system.
In step 560, the received data is processed by the cellular communications
device. This data processing task can include forwarding the data from the
received
pages to a controller, such as a PLC, to program control operations for
completion by
that device. The cellular communications device typically forwards the
received data
10 via a wired or wireless communications link to the controller. In turn, the
controller
can store the programming data within a look-up table maintained in its
memory. For
example, the received data can designate a slot or entry in the look-up table
and
programming data for storage within that look-up table slot. In step 562, the
process
returns to the START step 502 in FIG. 5A.
15 Returning now to FIG. 5A, an inquiry is conducted in decision step 530 to
determine whether the received page represents a data page in a single message
sequence. The placement of a 6 or 7 in the LSD of the MIN field of the
received page
designates a data page in a single message sequence. If the response to this
inquiry is
positive, the "YES" branch is followed from step 530 to step 532. Otherwise,
the
20 process 500 terminates at the EXIT step 534.
FIG. 5D is a logical flowchart diagram illustrating the sequence of steps
completed by a exemplary process for processing a data page representing a
single
message sequence, alternative described as "Data Page Single." Referring to
FIG.
5D, the receipt of a single data page message at step 532 initiates a data
collection
25 process at the cellular communications device. In step 570, the data field
of the data
page is extracted and stored as data digits. The data digits extracted from
the data
page are typically stored as digits 0 and 1 in big-endian order at the
cellular
communications device. In step 572, all timers and flags are cleared at the
cellular
communications device because the extraction of data from the single page
message
30 completes the data collection task. In step 574, the cellular
communications device
sends an acknowledgement signal to confirm receipt of the single data message.
The
cellular communications device typically sends the acknowledgement signal as
an
Autonomous Registration signal having a pattern AAAAAAdd. The
"AAAAAA (hex)" pattern represents an Acknowledge Pattern, whereas the "dd"
represents the received data of the single data message in BCD format in big-
endian
CA 02320012 2000-09-18
31
order. The cellular communications device transmits the acknowledgement signal
via
the RECC to the MSC of the CMR system. In turn, the collected data is
processed in
step 576 at the cellular communications device. Representative processing
operations
include the tasks described above in connection with step 560 of FIG. 5C. In
step
578, the process returns to the START step 502.
If the response to the inquiry conducted in decision step 530 is negative, the
process proceeds to the EXIT step 534. As shown in FIG. 5E, the EXIT step 534
requires the clearing of all flags and the termination of time periods by all
timers at
the cellular communications device, as shown in step 580. In step 582, the
process
returns to the START step 502.
As shown in FIGs. 5A, 5B, 5C, 5D, and 5E, collectively described as FIG. 5,
when a data sequence carried by one or more pages is to be sent, the MSC 24,
operating as a gateway, will send via the FOCC a target page to prompt an
action by
one or more cellular communications device 34 having the assigned target MIN.
Cellular communications devices 34 are also described herein as a target
radio. The
MSC 24 will transmit the target pages twice over the FOCC within a
predetermined
time period; such as a 60 second period, where the second page is preferably
received
after the first page during a period greater than 30 seconds and less than 60
seconds.
Upon receipt of a target page to its Primary (slot 0) MIN or Group 1 MIN (slot
1), the target radio 34 will start a prime timer having the predetermined time
period,
such as a 60 second timer. If the prime timer expires prior to a subsequent
target page
carrying the same MIN, the target radio 34 will execute a default function. If
a
second target page arrives prior to the prime timer's expiration, however, the
target
radio 34 activates an ARM timer having a predetermined time period, such as 60
seconds, and awaits receipt of the first data message, i.e., a page carrying
data content.
If that message is received via the FOCC prior to timer expiration, it will
reset the
ARM timer and continue to reset until all data is received. If at any time the
ARM
timer expires, then the target radio 34 will return to normal operation. All
non-armed
radios will ignore the data pages. The MSC will only simultaneously transmit
one
data sequence per MSCID to avoid target radio confusion.
The two data pages, called FOCC data messages, convey decimal digits of
data via the FOCC to the now-armed target radio. If both FOCC data messages
are
correctly received, the target radio 34 preferably sends to the MSC 24 an
Autonomous
Registration signal with the upper 12 bits containing the Acknowledge Pattern
"AAA
CA 02320012 2000-09-18
32
(hex)". The lower 20 bits are the received data represented in BCD in big-
endian
order.
If a single FOCC data message is used (LSD of 6, 7), and this data page is
correctly received, the target radio 34 will send an Autonomous Registration
signal
with the upper 24 bits containing the Acknowledge Pattern "?~~AAAA (hex)". The
lower 8 bits are the received data represented in BCD in big-endian order.
Table 3 describes a representative example for the communication of a target
MIN and data content via a sequence of pages to a cellular communications
device via
the MSC. For this example, the assigned block of MINS are "009-100-0000 to 009-
100-099." The memory of cellular communication devices responsive to target
MINS
within this assigned block have a memory mask set to "009-100-Oaaa," where 'a'
indicates a "wildcard" of zero through nine. In other words, the cellular
communication devices representing the family of target radios have a memory
mask
set to "0090100-Oaaaa, wherein the least four significant digits of the mask
can be any
number from zero through nine. To communicate the S-digit data set of "47109"
to a
target radio, the page sequence defined in Table 3 is communicated as data
pages by
the MSC via the FOCC.
First, a target page having a target MIN assigned to the desired set of
cellular
communications devices 34 or target radios are transmitted by the MSC 24 via
the
FOCC within a 60 second period. For example, the MSC can send the target page
having the MIN of "009-100-0999 to prompt an action by these target radios.
Each
activated target radio will now monitor the FOCC for one or more pages
containing
data content, also described as an data pages. For the example described in
Table 3,
the data content of "47109" is transmitted by the MSC as a pair of data pages,
using
either a default "even" MIN structure or a default "odd" MIN structure. For
the even
MIN structure, the first data page comprises "009-100-0900" to communicate the
data
content "09" and the second data page comprises "009-100-0174". In turn, the
target
radio can acknowledge receipt of this data content by sending an Autonomous
Registration signal with the upper 12 bits comprising the Acknowledge Pattern
of
"AAA" (hex) and the lower 20 bits representing the received data content of
"47109".
CA 02320012 2000-09-18
33
Table 3
Representative Example of a Paging Sequence
Block of MINs assigned: 009-100-0000 to 009-100-0999
(1K total)
MIN Mask set to: 009-100-Oaaa where 'a' indicates
a
wildcard 0 through 9
FOCC DATA to be conveyed: 47109
FOCC Data Page 1: 009-100-0900 (for even Default
MII~
009-100-0901 (for odd Default
MII~
FOCC Data Page 2: 009-100-0174 (for even Default
MII~
009-100-0175 (for odd Default
MII~
Registration Response: AAA47109 (hex)
Table 4 describes another representative example for the communication of a
target MIN and data content via a sequence of pages to a cellular
communications
device via the MSC. In contrast to the example shown in Table 3, however, the
data
content is transmitted by the MSC 24 to each target radio 34 in the form of a
single
data page "009-100-0586" for an even default MIN or "001-100-0587" for an odd
default MIN."
Table 4
Alternative Example of a Paging Sequence
Block of MINs assigned: 009-100-0000 to 009-100-0999
(1K total)
MIN Mask set to: 009-100-Oaaa where 'a' indicates
a
wildcard 0 through 9
FOCC DATA to be conveyed: 85
FOCC Data Page 1: 009-100-0586 (for even Default
MII~
009-100-0587 (for odd Default
MII~
Registration Response: AAAAAA85 (hex)
Commands and data can be transmitted by the MSC 24 via the cellular
network control channel 38 to cellular communications devices 34 coupled to
CA 02320012 2000-09-18
34
controllers 32', such a programmable logic controllers (PLCs). A controller
32', also
described as a PLC, can be programmed by sending the programming content from
the MSC 24 to the cellular communications device 34 coupled to that
controller. In
turn, the cellular communications device 34 can forward the received
programming to
the controller 32'. For controller applications, an inventive data protocol
can be used
to support the performance of control tasks relative to a pre-defined schedule
of
events. Examples of applications that are able to use such a protocol include,
but are
not limited to, irrigation systems, gate controls, entry systems, lighting
controls, etc.
For a representative weekly schedule application, each PLC can be
programmed in memory based on a 100-entry look-up table to minimize the amount
of weekly paging required for a given unit. Each entry (slot) in the look-up
table can
be stored in a memory location of the PLC at the time of manufacture or prior
to
installation for the specific control application. In the alternative, the
look-up table
programming can be communicated to the PLC by sending a programming entry to
1 S the corresponding cellular communications device. A typical schedule for a
control
application is a one-week schedule. An example of a look-up table for a single
use
facility, based on 5 schedules (00 -- 04) and 24-hour time (0000 -- 2400
hours), is
shown below in Table 5. The schedule shown in Table S can be preprogrammed
into
a PLC during the start-up phase of the controllable system.
Table 5
Schedule for a Representative Control Application
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
ScheduleOn Off On Off On Off On Off On Off On Off On Off
00 160021001800220018002200 18002200180022001800220016002100
01 161521151815221518152215 18152215181522151815221516152115
02 163021301830223018302230 18302230183022301830223016302130
03 1700230017002300 170023001700230017002300
04 1700210017002100 170021001700210017002100
An example of a representative page message structure for a schedule
command is shown in Table 6.
CA 02320012 2000-09-18
Table 6
Schedule Command Message Structure
Command MIN: 080 100 CNNA
5 where,
C - is the designator for command MIN
NN - is the two digit slot number in the look-up table
A - is either an 8 or a 9 to denote a standard schedule
command
This exemplary schedule command page has the MIN format of 080-100-
CNNA, where the MIN suffix CNNA is a 4-digit representation of the combination
of
the command MIN designator (C), the look-up table slot number (NN) and the
schedule command (A). The "080-100" portion of the MIN has been set aside or
reserved for use in connection with weekly schedule paging applications.
The paging of a unit for each week can comprise the representative paging
sequence shown in Table 7.
Table 7
Schedule Command Paging Sequence
First Page: Default MIN (example: 080-100-51 S 1)
Second Page: Schedule MIN (example: 080-100-1039)
where,
1- is the designator for the command MIN
03 is the schedule, or slot in the look-up table (memory location)
9 - is the odd designator for a standard schedule
The first page serves as a target page having the default MIN or target MIN to
alert the desired target radios to monitor the FOCC for schedule programming
information in the form of another page, typically a schedule command page. If
a
target radio having the MIN mask corresponding to the default MIN "080-101-
5151"
receives a page having that MIN, then the target radio will start to monitor
the FOCC
for a page carrying the schedule MIN. The schedule command page carries the
data
content of "1039", which designates the page as a command page, defines the
CA 02320012 2000-09-18
36
appropriate slot in the programming look-up table, and identifies the standard
schedule.
Once the target radio has received both the target page and the schedule
command page, the target radio issues an Autonomous Registration signal
serving as
S an acknowledgment of the command receipt. This acknowledgement comprises the
form " ' for at least 64 seconds after the target page has been received.
The "AAAAAA" field represents an Acknowledgment Pattern, whereas the "NN"
field represents the looking table slot number. If the registration
acknowledgment is
not received, then the page sequence can be reissued for a predetermined
number of
times, typically up to two more times by the MSC.
FIG. 6 illustrates the steps of an exemplary process for programming a
controller, such as a PLC, by sending a sequence of pages via a cellular
network
control channel to a cellular communications device. Turning now to FIG. 6, an
exemplary programming process 600 is initiated at the START step 605 and
proceeds
to step 610. The cellular communications device monitors the cellular network
control channel in step 610 for pages transmitted by the MSC via the FOCC.
Representative pages carned by the FOCC can include target pages, data pages
schedule command pages, ON/OFF override command pages and data request
command pages. Representative examples of target messages and data messages
have
been described above in connection with FIG. S and Tables 3 and 4. Schedule
command messages are described above in Tables 6-7 and below in Tables 8-10.
ON/OFF overnde command pages are described below in Table 11, while data
request command messages are described below in Table 12.
In decision step 615, an inquiry is conducted to determine whether the
cellular
communications device has received a target page having a specific identifier
assigned to that device. If the response to this inquiry is negative, the "NO"
branch is
followed from step 615 to step 610. The receipt of a target page by the
cellular
communications device can transition the focus of monitoring operations from
target
pages to schedule command pages. In an alternative embodiment, the receipt of
a pair
of target pages within a predetermined time period will result in the
transition of this
monitoring operation from target pages to schedule command pages. In either
embodiment, the reception of target pages) having a matching identifier
results in a
transition of the focus of monitoring operations completed by the device.
In decision step 620, an inquiry is conducted to determine whether a schedule
command page has been received within a predetermined time period by the
cellular
CA 02320012 2000-09-18
37
communications device. A negative response to this inquiry results in the
process
looping back to step 610 to continue monitoring operations. On the other hand,
a
positive response results in the process proceeding from decision step 620 via
the
"YES" branch to step 625.
In step 625, the cellular communications device extracts a schedule command
from the schedule command page and forwards that command to a controller, such
as
a PLC coupled to the device. The data content of the scheduled command
typically
defines a slot for entry in a programming look-up table maintained in memory
by the
PLC. The look-up table includes multiple slots or entries, each stored in a
memory
location and containing programming data defining control operations for the
PLC.
In step 630, the PLC retrieves a programming command from the look-up
table slot identified by the schedule command page to initiate programming
operations by the PLC.
In step 635, the cellular communications device can send an acknowledgement
signal , via the cellular network control channel. The acknowledgment signal
is
typically formatted as an Autonomous Registration signal having a ESN field
with the
form " ." The cellular communications device transmits the
acknowledgment signal via the RECC to the MSC to confirm receipt of the
schedule
command page.
An exemplary process for reprogramming the slots in the schedule look-up
table of a PLC can be based on a communication by an MSC of a paging sequence
over the FOCC to a cellular communications device coupled to the PLC. For a
weekly schedule application involving a PLC having 8 controllable relays, the
total
number of permutations for the combination of 256 relay state possibilities,
288, 5-
minute time segments in a 24-hour day, and a 7 day/week schedule is 516096.
Consequently, an exemplary format for the programming data stream is SSPPPPPP,
where "SS" is the slot number and "PPPPPP" is the permutation number. The data
sent to the target radio comprises a slot number and a permutation number.
This
results in a total of four command pages and a page for the Default MIN. After
every
two command pages, the target radio preferably acknowledges receipt of the
schedule
commands with a Autonomous Registration signal having an ESN of the format
"AAAAdddd". For this ESN format, "AA.AA" signifies that this message is a page
acknowledgment (an Acknowledgment Pattern) and "ddd" represents the data
elements of the received pages.
CA 02320012 2000-09-18
38
The digits in a schedule command page can be used in accordance with the
information shown in Table 8.
Table 8
Function of Least Significant Digit in MIN for Schedule Command Pages
LSD of MIN Function
0,1 First page of Look-up Table Programming
2,3 Second page of Look-up Table Programming,
Data Request Pages, On/Off Override
Pages
4,5 Third page of Look-up Table Programming
6,7 Fourth page of Look-up Table Programming
8,9 Weekly Schedule Pages
As shown in Table 9, to reprogram the slots in the schedule look-up table of a
PLC, an exemplary communication process is completed based on a paging
sequence
communicated over the FOCC between the MSC and a cellular communications
device coupled to the PLC.
Table 9
Page Sequence for a Typical PLC Reprogramming Operation
1. MSC transmits default or target page to target radio(s).
2. MSC transmits schedule command page containing the slot in the
schedule look-up table to the target radio(s).
3. MSC transmits schedule command page containing the 2 most
significant digits of the permutation to the target radio(s).
4. Each target radio transmits to the MSC an Autonomous Registration
signal containing the slot number and the 2 most significant digits of
the permutation to acknowledge receipt of the schedule command
pages.
5. MSC transmits schedule command page containing the next 2
significant digits of the permutation to the target radio(s).
CA 02320012 2000-09-18
39
6. MSC transmits schedule command page containing the 2 least
significant digits of the permutation to the target radio(s).
7. Each target radio transmits to the MSC an Autonomous Registration
signal containing the next 2 significant digits and the 2 least significant
digits of the permutation to acknowledge receipt of the schedule
command pages.
An example of a paging sequence for reprogramming communications is
shown in Table 10:
Table 10
PLC Programming Example
Slot Number to program: 89
Permutation number: 503862
Page l: 080-100-5151
Page 2: 080-100-1891
Page 3: 080-100-1503
Registration 1: AAA.A 8950
Page 4: 080-100-1385
Page 5: 080-100-1627
Registration 2: AAAA3962
For the representative example of a sequence of pages described in Tables 9
and 10, the first page represents the target page having a default MIN to
alert
particular target radios having the corresponding MIN mask that commands
and/or
data will be communicated via the FOCC for use by those target radios. The
representative example of this default MIN page is "080-100-5151," which
designates
an odd default MIN. The schedule slot number of "89" is defined by the second
page
of "080-100-1891." The least significant digit of "1" designates this page as
the first
page of look-up table programming. The third page of this paging sequence,
"080-
100-1503" defines the 2 most significant digits of the permutation, "50," and
includes
the least significant digit of "3" to designate this page as the second page
of look-up
table programming. In response to this page sequence, the target radio issues
an
acknowledgement signal in the form of an Autonomous Registration signal
CA 02320012 2000-09-18
"AAA.A8950," which contains the slot number "89" and the 2 most significant
digits
of the permutation "50."
In response to the acknowledgement signal, the MSC issues the fourth page of
this paging sequence, "080-100-1385," which defines the next 2 most
significant
5 digits of the permutation, "38," and includes the least significant digit of
"5" to
designate this page as the third page of look-up table programming. In turn,
the MSC
transmits the fifth and final page of the paging sequence, "080-100-1627,
which
defines the 2 least significant digits of the permutation, "62," and includes
the least
significant digit of "7" to designate this page as the fourth page of look-up
table
10 programming. In response to this page sequence, the target radio issues an
acknowledgement signal in the form of Autonomous Registration signal
"AA.A.A3962," which contains the next 2 significant permutation digits "39"
and the 2
least significant permutation digits "62."
If a programming change occurs locally, typically by the end user or a field
15 technician, in a schedule look-up table, then the target radio can issue a
registration
sequence to the MSC. In turn, the MSC can forward this information to the data
collection system as an update for the schedule information maintained at an
Operations Center responsible for schedules.
FIG. 7 is a logical flow chart diagram illustrating the steps for an exemplary
20 process for reprogramming a controller, such as a PLC, by communicating a
sequence
of pages via a cellular network control channel to a cellular communications
device
operating within a CMR system. Turning now to FIG. 7, an exemplary
reprogramming process 700 is initiated at the START step 705 and continues to
step
710. In step 710, the cellular communications device monitors the cellular
network
25 control channel. In particular, the cellular communications device monitors
the
FOCC for pages issued by the MSC of the CMR system. In decision step 715, an
inquiry is conducted to determine whether the cellular communications device
has
received a target page having a specific identifier assigned to that device.
If the
response to this inquiry is negative, the "NO" branch is followed from step
715 to step
30 710 to continue monitoring operations at the cellular communications
device. If, on
the other hand, the cellular communications device receives a target page
having a
matching identifier, the "YES" branch is followed from step 715 to step 720.
In decision step 720, a determination is made whether the cellular
communications device has received a schedule command page having a schedule
35 table slot number and a schedule command page having programming data. If
the
CA 02320012 2000-09-18
41
response to this inquiry is negative, the "NO" branch is followed from step
720 to step
710 to continue monitoring operations. If, on the other hand, the cellular
communications device has received both schedule command pages within a
predetermined time period, the "YES" branch is followed from step 720 to step
725.
In step 725, the cellular communications device extracts the schedule table
slot
number and the programming data from the pair of scheduled command pages and
forwards this information to the PLC coupled to the device. In turn, the
cellular
communications device can send an acknowledgement signal via the cellular
network
control channel in step 730. The acknowledgement signal is typically formatted
as an
Autonomous Registration signal for communication via the RECC to the MSC of
the
CMR system.
In decision step 735, a determination is made whether the cellular
communications device has received additional scheduled command pages
containing
data during a predetermined time period. If the response to this inquiry is
negative,
the "NO" branch is followed from step 735 to step 710 to continue monitoring
operations at the cellular communications device. If, on the other hand, the
cellular
communications device has received additional schedule command pages in a
timely
fashion, the "YES" branch is followed to step 740. For an exemplary
embodiment,
programming data is typically carried by this pair of additional scheduled
command
pages. The programming data carried by the additional scheduled command pages
is
extracted by the cellular communications device and forwarded to the PLC in
step
740. This programming data can be combined with the slot number and
programming
data received by the PLC in step 725 to support a reprogramming operation at
the
PLC. For example, the combination of programming data can be stored by a look-
up
table at the slot number identified by a received scheduled command page to
update
or to reprogram the programming data at that look-up table slot.
In step 745, the cellular communications device can send an acknowledgement
signal via the cellular network control channel to acknowledge receipt of the
additional schedule command pages. The cellular communications device
typically
transmits the acknowledgement signal as an Autonomous Registration signal via
the
RECC to the MSC. of the CMR system.
For a representative PLC, there exists 8 preprogrammed Modes, or Relay
States. An exemplary example of the page structure for an On/Off overnde
command
MIN is shown in Table 11.
CA 02320012 2000-09-18
42
Table 11
Page Structure for an On/Off Override Command MIN
On/Off Command: 080 100 1 FMB
S where,
F - is either a 9 (for On) or an 8 (for Off)
M - is the preprogrammed mode in the PLC
B - is either a 2 or a 3 (even or odd) depending on the default
MIN
The paging sequence for the On/Off Overnde Command typically comprises a
target
page having the default MIN followed by the command page. Once a target radio
has
received both pages, it issues an Autonomous Registration signal of the format
AAAAAAAA at least 64 seconds after reception of the default MIN. If this
acknowledgment signal is not received by the MSC via the FOCC within a certain
time period, then the MSC reissues the page sequence.
FIG. 8 illustrates an exemplary process for communicating pages via a cellular
network control channel of a CMR system to communicate an ON/OFF overnde
command to a controller coupled to a cellular communications device. Turning
now
to FIG. 8, an exemplary process 800 is initiated at the START step 805 and
proceeds
to the step 810. In step 810, the cellular communications device monitors the
cellular
network control channel for one or more pages issued by the MSC via the FOCC.
In
decision step 815, an inquiry is conducted to determine whether the cellular
communications device has received a target page having a specific identifier
assigned to the device. If the response to this inquiry is negative, the "NO"
branch is
followed to step 810 from step 815 to continue monitoring operations by the
cellular
communications device. If the cellular communications device has received a
target
page with a matching identifier, the "YES" branch is followed from step 815 to
step
820.
In step 820, a determination is made whether the cellular communications
device has received a command page carrying an ON/OFF override command via the
cellular network control channel. If the cellular communications device has
not
received the command page, the "NO" branch is followed from step 820 to step
810
to continue monitoring operations. If, on the other hand, the cellular
communications
device has received a command page with an ON/OFF override command during a
CA 02320012 2000-09-18
43
predetermined time period, the process follows the "YES" branch from step 820
to
step 825. The cellular communications device forwards the ON/OFF overnde
command in step 825 to the PLC coupled to the device. The PLC can store the
ON/OFF overnde command within memory, such as the programming look-up table.
In step 830, the cellular communications device transmits an
acknowledgement signal via the cellular network control channel to acknowledge
receipt of the command page carrying the ON/OFF override command. The
acknowledgment signal is preferably formatted as an Autonomous Registration
signal
carried by the RECC for receipt by the MSC of the CMR system.
In a representative example of a PLC device, there exists 10 preprogrammed
responses to data requests. An example of the structure for data request
command
page is shown below in Table 12.
Table 12
1 S Page Structure for a Data Request Command MIN
Data Request Command: 080 100 1FMB
where,
F-isa6
M - is the preprogrammed data request format (0 through 9)
B - is either a 2 or a 3 (even or odd) depending on the default
MIN
The paging sequence for the Data Request Command consists of the target page
carrying the default MIN followed by the data request page. Once the target
radio has
received both pages, it can issue an Autonomous Registration signal carrying
the
requested data in the form of a data message. If the registration signal is
not received
within a certain time period of the MSC, then the page sequence can be
reissued by
the MSC.
In normal operation, when the target radio issues an alarm, the alarm message
comprises an Autonomous Registration signal transmittal via the RECC. This
alarm
message can be followed by an Autonomous Registration signal carrying specific
information related to that alarm. Regular status registrations are preferably
accomplished by a single registration formatted as an Autonomous Registration
signal.
CA 02320012 2000-09-18
44
FIG. 9 illustrates an exemplary process for communicating pages via a cellular
network control channel of CMR system to communicate a data request command to
a controller coupled to a cellular communications device. Turning now to FIG.
9, an
exemplary process 900 is initiated at the START step 905 and proceeds to the
step
910. In step 910, the cellular communications device monitors the cellular
network
control channel for one or more pages issued by the MSC via the FOCC. In
decision
step 915, an inquiry is conducted to determine whether the cellular
communications
device has received a target page having a specific identifier assigned to the
device. If
the response to this inquiry is negative, the "NO" branch is followed to step
910 from
step 915 to continue monitoring operations by the cellular communications
device. If
the cellular communications device has received a target page with a matching
identifier, the "YES" branch is followed from step 915 to step 920.
In step 920, a determination is made whether the cellular communications
device has received a data request page carrying a data request command via
the
cellular network control channel. If the cellular communications device has
not
received the data request page, the "NO" branch is followed from step 920 to
step 910
to continue monitoring operations. If, on the other hand, the cellular
communications
device has received a data request page with a data request command during a
predetermined time period, the process follows the "YES" branch from step 920
to
925. The cellular communications device forwards the data request command in
step
925 to the PLC coupled to the device. The PLC can respond to the data request
command by forwarding the requested data to the cellular communications device
in
step 930. In turn, the cellular communications device can issue in step 935 an
Autonomous Registration signal formatted as a data message carrying the
requested
data. For the exemplary embodiment, the requested data is typically a
preprogrammed response stored in memory of the PLC and associated with the
particular data request.
A representative projection of the monthly traffic loading for a CMR system
using the process controller scheduling protocol described above in Tables 5-
12 is
illustrated below in Table 13.
CA 02320012 2000-09-18
Table 13
Traffic Loading
Frequency Messages
per
month
Paging due to Weekly Schedule Changesonce per week 8
Acknowledgments for Weekly Scheduleonce per week 4
Changes
Paging due to Look-up Table once per 3 months1.6
Programming
Acknowledgments for Look-up Table once per 3 months0.6
Programming
Pages for On/Off Override or 1 function per
month 2
Data Requests
Acknowledgments for On/Off 1 functions 1
per
Overnde or Data Requests month
Alarm/Status Registrations 43 messages 42
per
month
Total Pages 11.6
Total Registration47.6
Total Messages59.2
Percent Paging19.6%
Percent 80.4%
Registrations
5 It should be understood that the particular embodiments described herein
have
been disclosed by way of example and that other modifications may occur to
those
skilled in the art without departing from the spirit of the inventive concept.
