Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED PAGING SCHEME
FOR CALL DELIVERY WITHIN
A CELLULAR TELEPHONE NETWORK
BACKGROUND OF THE INVENTION
~~ t,~n;ral Field of the Invention
The present invention relates to cellular telephone networks and, in
particular,
to the paging of a mobile station in connection with the termination of an
incoming
1 o call.
TIPCr~ptinn ~f Related Art
Operation of a cellular telephone network to handle an incoming call dialed to
a cellular subscriber mobile station is well known. Responsive to receipt at
an
originating (or gateway) switching node of the incoming call dialed to a
mobile
station, a location request (send routing) message is sent to the home
location register
for the dialed mobile station. The home location register then identifies a
switching
node currently serving the dialed mobile station. A routing request (provide
roaming)
message is then sent from the home location register to the serving (or
visited)
switching node to prepare for delivery of the call. The serving switching node
then
2 o pages for the mobile station within the network. Responsive to a paging
acknowledgment, the mobile station is located and the serving switching node
assigns
an appropriate routing number (for example, a temporary location directory
number
or a roaming number) for that location. The routing number is then delivered
to the
originating switching node via the home location register where it is used to
establish
2 5 a trunk call connection between the originating switching node and the
serving
switching node. Delivery of the call to the mobile station from the serving
switching
node is then accomplished by establishing a connection with a base station
currently
serving the mobile station. A radio frequency communications link is then
established
between the base station and the mobile station to carry the call connection.
3 o Cellular telephone networks utilize a control channel to broadcast control
signals within each of the included plurality of cells. In connection with the
locating
of a mobile station, a paging signal is transmitted over the control channel
for certain
ones of the cells. In order to provide the greatest likelihood of establishing
location,
the paging signal must be transmitted within every cell covering the service
area of the
3 5 network. The capacity of the control channel, however, is limited because
its data
transmission rate is relatively slow and it is used by the network to transmit
many
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control related messages other than paging signals. Paging in every cell is
then not an
acceptable option as this would adversely affect control channel capacity.
Procedures
then must be established to utilize the limited capacity of the control
channel as
efficiently as possible, while at the same time ensuring an acceptable success
rate for
paging to facilitate call delivery.
One paging scheme that has been successfully utilized is to define a pluraiity
of location areas (LA's) within the service area (SA) of the cellular
telephone network.
Each location area typically includes a plurality of individual cells. As
mobile stations
move about the service area, they register with the network each time they
enter into
1 o a new location area. A record of this registration is kept, and selective
paging is
performed in each of the cells of the location area where the called mobile
station last
registered. If the paging signal is not acknowledged, the network next pages
in a
paging area (PA) which is larger than the location area in which the mobile
station last
registered, but smaller than the service area. Paging over the entire service
area (i.e.,
global) for a mobile station is performed, if at all, only in emergency
situations.
It is known to offer cellular telephone service subscriptions that restrict
the
areas within which the subscriber is authorized to receive service. In a call
delivery
(restricted) service type subscription, subscribers are given the option of
restricting the
areas within which terminating calls may be delivered. With such a service, a
mobile
2 0 station is paged (typically on a location area basis) in connection with
an incoming call
delivery attempt. Responsive to a paging acknowledgment, the location of the
mobile
station is known and can be compared to a list of permitted call termination
locations.
If the mobile station is located within a permitted location, the call is
delivered.
Otherwise, the call is rejected. The use of conventional paging schemes in
connection
2 5 with this service, however, is inefficient and wasteful of limited paging
resources
because subscriber mobile stations may often be paged in cells where they are
not
authorized to receive cellular calling service.
In a long haul mobile switching center type subscription, service is offered
in
a small market where the use of a dedicated switching node is not justified.
Excess
3 o capacity from a switching node in a neighboring market is then used to
serve
subscribers in the small market. With such a service, a mobile station is
paged in
connection with an incoming call delivery attempt in the location area for the
serving
switching node. This location area typically includes cells located outside of
the small
market service area. Furthermore, in many instances the small market
subscribers are
3 5 not even authorized to receive service outside of their own market. Again,
the use of
conventional paging schemes in connection with this service is inefficient and
wasteful
of limited paging resources because subscriber mobile stations may often be
paged in
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cells where they either are not likely to be located, or are not authorized to
receive
cellular calling service.
What is needed then, especially in connection with the provision of any type
of restricted service subscription, is a more efficient paging scheme that
takes into
account not only the location where a subscriber is likely to be found, but
also the
location where the subscriber is authorized to receive cellular calling
service.
SUMMARY OF THE INVENTION
In general, a paging scheme is presented where mobile stations are paged, not
conventionally in the locations where they are likely to be found, but rather
in those
1 o locations where the mobile station is authorized to receive cellular
calling service.
Thus, in connection with the provision of a restricted service area
subscription wherein
a mobile station is authorized to receive cellular calls in only a certain
portion of the
cellular service area, the mobile station is paged in response to an incoming
call only
in that certain portion.
More particularly, responsive to receipt at an originating switching node of
an
incoming call, a location request (send routing) message is sent to the home
location
register for the called mobile station. A routing request (provide roaming)
message
is then sent from the home location register to the switching node identified
by the
home location register as currently serving the called mobile station. The
serving
2 0 switching node then pages for the called mobile station only in those
areas it services
which also comprise areas within which the called mobile station is authorized
by its
subscription to receive cellular calling service. Responsive to a paging
acknowledgment, an appropriate routing number is assigned and transmitted back
to
the originating switching node. The assigned routing number is then used to
establish
2 5 a trunk connection between the originating switching node and the base
station
controller for purposes of effectuating call delivery.
In one embodiment of the invention, the certain areas within which the called
mobile station is authorized by its subscription to receive cellular calling
service are
stored in the home location register and provided to the serving switching
node along
3 o with a downloaded subscriber service profile. Responsive to a routing
request
message relating to an incoming call, the serving switching node determines
which of
those certain areas that it services, and then pages for the mobile station
only in those
determined areas. In the event the switching node services none of the
determined
areas, or no paging acknowledgment is received from the mobile station, a
subscriber
3 5 not available message is returned to the originating switching node.
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In another embodiment of the invention, certain directory B-number series are
assigned to mobile stations having restricted service area subscriptions.
Pursuant to
this subscription, a mobile station in the certain directory B-number series
is
authorized to receive cellular calling service in only certain areas.
Responsive to a
routing request message relating to an incoming call, the serving switching
node
determines which of those certain areas specified by the B-number series that
it
services, and then pages for the mobile station only in those determined
areas. In the
event no paging acknowledgment is received from the mobile station, a
subscriber not
available message is returned to the originating switching node.
1 o BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the method and apparatus of the present
invention may be acquired by reference to the following Detailed Description
when
taken in conjunction with the accompanying Drawings wherein:
FIGURE 1 is a schematic diagram of a cellular telephone network;
FIGURE 2 is a signal flow and node operation diagram illustrating the flow of
signals in connection with the prior art termination of an incoming call;
FIGURE 3 is a cell diagram illustrating a plurality of cells grouped to form
location areas;
FIGURE 4 is a signal flow and node operation diagram illustrating the flow of
2 o signals in connection with a specific example of the termination of an
incoming call
in accordance with the present invention;
FIGURES SA-SE are diagrams illustrating various relationships between
mobile station location and authorized service areas and their affect on
mobile station
paging; and
2 5 FIGURES 6A-6F are flow diagrams illustration operation of the paging
scheme of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is now made to FIGURE 1 wherein there is shown a schematic
diagram of a cellular telephone network 10 including a plurality of
interconnected
3 o switching nodes (SN) 12. Although only two switching nodes 12 are shown,
it will
be understood that the network 10 likely includes many more interconnected
nodes.
The first and second switching nodes 12(1) and 12(2) may comprise any one of a
number of known telecommunications switching devices, including mobile
switching
centers (MSC's), as commonly used and known in the art for providing either
digital
3 5 or analog cellular telephone service to a plurality of mobile stations
(MS) 14. The
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switching nodes 12 are interconnected with each other for communication via
both
voice trunks 18 (illustrated with broken lines) and signaling links 16
(illustrated with
solid lines) providing a known ISUP (or Rl or R2) type connection. The voice
trunks
18 provide voice and data communications paths used to carry subscriber
communications between the switching nodes 12. The signaling links 16 carry
command signals between the switching nodes 12. These signals may be used, for
example, in setting up and tearing down voice and data communications links
over the
voice trunks 18 and controlling the provision of calling services to the
mobile
stations 14. The switching nodes 12 are also connected to a data base 20
comprising
1 o a home location register (HLR) by means of signaling links 22 providing a
known
Mobile Application Part (MAP) or IS-41 type connection. The data base 20
stores
information concerning the mobile stations 14 comprising location information
and
service information.
In one implementation, the switching nodes 12 are further connected to at
least
one associated base station controller (BSC) 24 via both a signaling link 26
and a
voice trunk 28. Only one base station controller 24 is shown connected to the
switching node 12(1) in order to simplify the illustration. The voice trunk 28
provides
a voice and data communications path used to carry subscriber communications
between the switching node 12( 1 ) and its base station controller 24. The
signaling link
2 0 26 carnes command signals between the node 12 and its associated base
station
controller 24. The signaling link 26 and trunk 28 are collectively commonly
referred
to in the art as the "A interface". The base station controller 24 is then
connected to
a plarality of base stations (BS) 30 which operate to effectuate radio
frequency
communications with proximately located mobile stations 14 over an air
interface 32.
2 5 The base station controller 24 fimctions in a well known manner to control
this radio
frequency communications operation. In another implementation, the switching
node
12(2) is connected directly to the plurality of base stations (BS) 30. The
fimctionality
provided by the base station controller 24 in controlling the radio frequency
communications operation is then instead performed by the switching node
12(2).
3 0 Although direct communications links (signaling and/or trunk) are
illustrated
in FIGURE 1, it is understood by those skilled in the art that the links are
not
necessarily direct between the illustrated nodes, and may instead pass through
many
other communications nodes (not shown) of the mobile network, and perhaps even
utilize other communications networks (such as the public switched telephone
network
3 5 - PSTN). Illustration of the links in the "virtual" manner shown in FIGURE
1 is
therefore by way of simplification of the drawing. The cellular telephone
network 10
may comprise a Global System for Mobile (GSM) communications, an Advanced
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Mobile Phone System (AMPS), a digital Advanced Mobile Phone System (D-AMPS),
a code division multiple access (CDMA) system, or the like.
Reference is now made in combination to FIGURES l and 2, wherein FIGURE
2 is a signal flow and node operation diagram illustrating the flow of signals
in
connection with a specific example of the prior art termination of an incoming
call.
A call 100 dialed to the directory number (B-number) of mobile station 14(1)
originates from another cellular subscriber or the public switched telephone
network
(PSTN) and is received at the first (originating or gateway) switching node
12(1).
Using the signaling link 22, the originating switching node 12(1) interrogates
the
1 o home location register 20 with a location request (send routing) message
102. The
location request (send routing) message 102 is processed by the home location
register
20 to determine the location (i.e., second or serving switching node 12(2))
within the
cellular network 10 of the called mobile station 14( 1 ). Responsive to this
interrogation, the home location register 20 signals the serving switching
node 12(2)
for the called mobile station 14(1) over signaling link 22 with a routing
request
(provide roaming} message 104 to prepare for the call. The serving switching
node
12(2) then determines in action 106 whether the location (for example,
location area)
of the called mobile station 14(1) is known. This location may be identified,
for
example, based on information resulting from a most recent registration (not
shown)
of the called mobile station 14(1) as stored in a visitor location register
(VLR)
database 34 associated with the serving switching node 12(2). Preferably, the
serving
switching node 12(2) then pages 108 for the called mobile station 14{1 ) in
the known
location, and processes a page acknowledgment 110 to make a more precise
(cell)
location determination. In accordance with this determined location, the
serving
2 5 switching node 12(2) selects in action 112 an appropriate routing number
(for
example, a temporary location directory number (TLDI~ or a roaming number) for
that location (for example, taking in consideration LATA borders and other
concerns).
In this instance, the routing number is selected from a plurality of such
numbers
associated with the serving switching node 12(2). The selected routing number
is then
3 0 returned 114 to the originating switching node 12( 1 ) via the home
location register 20.
The incoming call is then delivered (through connected) 116 over the voice
trunk 18
using the routing number to the serving switching node 12(2) for attempted
completion to the called mobile station 14(1). Completion of the call involves
further
routing 118 the incoming call to the currently serving base station 30, and
then to the
3 5 called mobile station 14(1) over the air interface 32.
Reference is now made to FIGURE 3 wherein there is shown a cell diagram
200 illustrating a plurality of cells 202 grouped to form location areas 204.
For the
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sake of simplifying the illustration, only two location areas 204 are shown,
it being
understood, however, that the service area of a cellular telephone network
like that
shown in FIGURE 1 typically includes many more location areas. The first
location
area 204(1) includes cells 202(1)-202(5). The second location area 204(2)
includes
cells 202(6)-202(10).
Cellular telephone networks utilize instances of mobile station registration
to
ascertain mobile station location with an accuracy of about one location area
204. To
deterniine mobile station location with a greater degree of accuracy, the
system pages
(108 of FIGURE 2) for the mobile station in each cell 202 of the location area
204
within which that mobile station last registered. By processing a received
paging
acknowledgment (110 of FIGURE 2) from the mobile station, the network may
ascertain mobile station location with an accuracy of about one cell 202.
Paging in this manner, however, can be inefficient and wasteful of limited
available control channel communications resources because mobile stations are
often
paged in cells where the mobile station either is not likely to be located, or
is not
authorized to receive service. For example, in a call delivery (restricted)
service type
subscription, subscribers may restrict the areas within which terminating
calls are to
be delivered. It would be more efficient then to page for the mobile station
only when
it could possibly be located within a permitted location, and further to page
only in
2 0 those cells where mobile station operation is actually permitted. As
another example,
in a long haul mobile switching center type subscription, service is extended
from a
switching node to a small market where the allocation of a dedicated switching
node
is not justified. With respect to the small market subscribers that do not
have roaming
permission, it would be more efficient then to page for the mobile station
only in those
2 5 cells of the small market where service is authorized.
In connection with the implementation of a call delivery (restricted) service
type subscription, a long haul mobile switching center type subscription, or
some other
type of restricted area service subscription, assume for exemplary purposes
that a
particular mobile station is authorized to receive incoming calls only when it
is located
30 within cells 202(3) and 202(5) of location area 204(1). As the particular
mobile
station moves about the service area, it would register with the network, and
its current
location within a certain one of the location areas 204 would be recorded in
the home
location register. When an incoming call is received for that particular
mobile station,
paging is conventionally performed in each cell 202 within the current
location area
3 5 204 where the called mobile station last registered. Following a paging
acknowledgment identifying the cell 202 within which the paged mobile station
is
located, a comparison is made to determine whether the identified cell 202
matches
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any of the authorized cells 202(3) or 202(5). If so, the call setup for
delivering the
incoming call is completed. Otherwise, the call is rejected.
If it is now assumed that the particular mobile station is located at point
"A"
within cell 202(9) of location area 204(2), paging for the mobile station in
each of the
cells 202 of location area 204(2) is wasteful and inefficient as the
restricted service
subscription would not authorize completion of the incoming call to the mobile
station
at its current location. Similarly, if it is now assumed that the particular
mobile station
is located at point "B" within cell 202(5) of location area 204(1 ), paging
for the mobile
station in each of the cells 202(1)-202(5) of location area 204(1) is wasteful
and
inefficient as the restricted service subscription would not authorize
completion of the
incoming call to the mobile station in each of those cells. Instead, and in
accordance
with the present invention, paging for the mobile station is effectuated
generally only
within those location areas 204, and particularly only within those cells 202,
within
which termination of the incoming call is permitted.
Refernng once again to FIGURE 1, in addition to storing the conventional
cellular information relating to service provision, service profiles and
mobile station
position information (i.e., location area), the home location register 20
fi~rther stores
in a register (R) 210 an identification of the particular areas (location
areas 204 or cells
202) within which an associated mobile station is authorized to receive
cellular calling
2 o service. This storage is associated with mobile station service provision,
service
profile and location information, and may be in the form of an authorization
code from
which the particular, service authorized, location area 204 and/or cell 202
identifications may be obtained through use of a look-up table or other known
method.
Alternatively, the storage may be in the form of a listing of the particular
location
2 5 areas 204 and/or cells 202 within which service is authorized.
As an alternative to storing an identification in the home location register
20
of the particular areas (location areas 204 or cells 202) within which an
associated
mobile station is authorized to receive cellular calling service (register
210), each
switching node 12 is programmed in a register (R) 216 with an identification
of one
3 0 or more directory number series (NPA-NXX-~;XXX) assigned to mobile
stations 14
which are restricted for use in only certain areas. Associated with each such
number
series stored in the register 216 is an identification of the particular areas
(location
areas 204 or cells 202) within which mobile stations 14 in that series are
authorized
to receive cellular calling service.
3 5 Reference is now made in combination to FIGURES 1 and 4, wherein FIGURE
4 is a signal flow and node operation diagram illustrating the flow of signals
in
connection with a specific example of the termination of an incoming call in
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accordance with the present invention. When a mobile station 14( 1 ) registers
with the
serving switching node 12(2), the service profile for that mobile station,
including the
register (R) 210 stored information identifying the particular areas (location
areas 204
or cells 202) within which the called mobile station 14(1) is authorized to
receive
cellular calling service (if available), is downloaded 98 for use in providing
cellular
service. A call 100 dialed to the directory number (B-number) of mobile
station 14(1 )
then originates from another cellular subscriber or the public switched
telephone
network (PSTN) and is received at the first (originating or gateway) switching
node
12(1). Using the signaling link 22, the originating switching node 12(1)
interrogates
the home location register 20 with a location request (send routing) message
102. The
location request (send routing) message 102 is processed by the home location
register
to determine the location (i.e., second or serving switching node 12(2), or
location
area 204) within the cellular network 10 of the called mobile station 14(1).
Responsive to this interrogation, the home location register 20 signals the
serving
15 switching node 12(2) for the called mobile station 14(1) over signaling
link 22 with
a routing request (provide roaming) message 104 to prepare for the call. The
message
104 includes the B-number for the called mobile station 14(1). The serving
switching
node 12(2) then determines in action 106 whether the location (for example,
within a
location area 204) of the called mobile station 14(1) is known. This location
may be
2 o determined, for example, based on information resulting from a most recent
registration 96 of the called mobile station 14(1) as stored in a visitor
location register
(VLR) database 34 associated with the serving switching node 12(2).
In one embodiment of the present invention, the serving switching node 12(2)
processes (action 212) the determined location information in view of the
information
2 5 obtained from the download 98 identifying the particular areas (location
areas 204 or
cells 202) within which the called mobile station 14(1) is authorized to
receive cellular
calling service (referred to as an "authorized area"). In another embodiment
of the
present invention, the serving switching node 12(2) analyzes the dialed B-
number in
connection with processing (action 212') the determined location information
in view
3 0 of the information obtained from the register 216 identifying restricted B-
number
series and the particular areas (location areas 204 or cells 202) within which
mobile
stations in those series are authorized to receive cellular calling service
(also referred
to as an "authorized area"). These processing actions 212 and 212' evaluate
whether:
(a) the location is unknown (FIGURE SA); (b) the location is known and
overlaps in
3 5 part with an authorized area (FIGURE SB); (c) the location is known and is
within an
authorized area (FIGURE SC); (d) the location is known and includes in whole
an
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authorized area (FIGURE SD); and, (e) the location is known and is different
from an
authorized area (FIGURE SE).
If (a) is satisfied, then the serving switching node 12(2) pages 108' for the
called mobile station 14( 1 ) in only those particular areas (location areas
204 or cells
202) associated with the serving switching node 12(2) within which the called
mobile
station 14(1) is authorized to receive cellular calling service. This is
illustrated in
FIGURE SA where paging is performed in authorized area (I), but is not
performed
in area (2).
If (b) is satisfied, then the serving switching node 12(2) first pages 108'
for the
called mobile station 14(1) in only those particular areas (location areas 204
or cells
202) associated with the serving switching node 12(2) where the known location
and
area within which the called mobile station 14{1) is authorized to receive
cellular
calling service overlap. This is illustrated in FIGURE SB where paging is
first
performed in authorized area ( 1 ), but not in any other areas (2-4). If this
page fails,
then the serving switching node 12(2) next (optionally) pages 108' for the
called
mobile station 14( 1 ) in the remaining area within which the called mobile
station 14( 1 )
is authorized to receive cellular calling service overlap. This is also
illustrated in
FIGURE SB where paging is performed in authorized area (2), but not in areas
(3-4).
If (c) is satisfied, then the serving switching node 12(2) first pages 108'
for the
2 0 called mobile station 14(1) in only those particular areas (location areas
204 or cells
202) associated with the serving switching node 12(2) comprising the known
location.
This is illustrated in FIGURE SC where paging is first performed in known
location
area (1), but not in any other areas (2-3). If this page fails, then the
serving switching
node 12(2) next (optionally) pages 108' for the called mobile station 14(1) in
the area
2 5 (encompassing the known location) within which the called mobile station
14( 1 ) is
authorized to receive cellular calling service overlap. This is also
illustrated in
FIGURE SC where paging is performed in authorized area (2), but not in area
(3).
This case illustrates a scenario where the authorized area comprises, for
example, a
few location areas.
3 o If (d) is satisfied, then the serving switching node 12(2) pages 108' for
the
called mobile station 14(1) in only those particular areas (location areas 204
or cells
202) associated with the serving switching node 12(2) within which the called
mobile
station 14(1) is authorized to receive cellular calling service. This is
illustrated in
FIGURE SD where paging is performed in authorized area (1), but is not
performed
3 5 in areas (2-3). This case illustrates a scenario where the authorized area
comprises, for
example, a few cells located within a location area (see, FIGURE 3).
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If (e) is satisfied, then the serving switching node 12(2) pages 108' for the
called mobile station 14(1) in only those particular areas (location areas 204
or cells
202) associated with the serving switching node 12(2) within which the called
mobile
station 14(1) is authorized to receive cellular calling service. This is
illustrated in
FIGURE SE where paging is performed in authorized area (1), but is not
performed
in areas (2-3). As an alternative, the serving switching node 12{2) may choose
not to
page for the called mobile station 14(1) at all.
A page acknowledgment 110 received from the mobile station 14(1) in
response to any of the pages 108' is processed to make a more precise location
determination. In accordance with this determined location, the serving
switching
node 12(2) selects in action lI2 an appropriate routing number (for example, a
temporary location directory number (TLDl~ or a roaming number) for that
location
(for example, taking in consideration LATA borders and other concerns). In
this
instance, the routing number is selected from a plurality of such numbers
associated
with the serving switching node 12(2). The selected routing number is then
returned
114 to the originating switching node 12(1) via the home location register 20.
The
incoming call is then delivered (through connected) 116 over the voice trunk
I8 using
the routing number to the serving switching node 12(2) for attempted
completion to
the called mobile station I4{1). Completion of the call involves further
routing 118
2 0 the incoming call to the currently serving base station 30, and then to
the called mobile
station 14(1) over the air interface 32.
If no page acknowledgment 110 is received (as indicated by the "X") to a page
108', and there are no more supplementary pages 108' to be made (see, e.g.,
FIGURES
SB and SD), a subscriber not available message is returned 214 to the
originating
switching node 12(1) via the home location register 20. It should further be
recognized that if the serving switching node 12(2) does not serve an
authorized area,
no page 108 or 108' is made, and a subscriber not available message is
returned 214
to the originating switching node 12(1) via the home location register 20.
Reference is now made to FIGURES 6A-6F wherein there is shown a flow
3 o diagram illustration operation of the paging scheme of the present
invention. In step
300, an incoming call is received. The home location register is then
interrogated with
a location request (send routing) message in step 302. The serving switching
node is
then signaled in step 304 with a routing request (provide roaming) message. A
determination is then made in step 306 as whether the location of the called
mobile
3 5 station is known.
If the location is not known, the process moves to FIGURE 6B (step 308).
Turning now to FIGURE 6B, paging is performed for the called mobile station
only
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those particular areas (location areas or cells) where the called mobile
station is
authorized to receive cellular calling service (step 310). If the serving
switching node
does not serve an authorized area, the process advances to mark the subscriber
as not
found in step 314. A determination is next made in step 312 as to whether a
paging
acknowledgment (ACK) has been received from the called mobile station. If the
determination made in step 312 is no, the subscriber is marked as not found
(step 314).
Otherwise, an appropriate routing number (for example, a temporary location
directory
number (TLDN) or a roaming number) is selected in step 316. The not found
indication or selected routing number is then returned in step 318, and the
incoming
call is through connected using the returned routing number to the called
mobile
station in step 320.
Returning again to FIGURE 6A, if the location is known, the known location
is compared to the authorized area in step 322. If the known location and
authorized
area overlap, the process moves to FIGURE 6C. Turning now to FIGURE 6C, paging
is performed for the called mobile station only those particular areas
(location areas
or cells) where there is an overlap between the known location and those
locations
where the called mobile station is authorized to receive cellular calling
service (step
324). If the serving switching node does not serve such an area, the process
advances
to mark the subscriber as not found in step 332. A determination is next made
in step
2 0 326 as to whether a paging acknowledgment (ACK) has been received from the
called
mobile station. If the determination made in step 326 is no, paging is then
(optionally)
performed for the called mobile station in those particular areas (location
areas or
cells) where the called mobile station is authorized to receive cellular
calling service
(step 328). A determination is next made in step 330 as to whether a paging
2 5 acknowledgment (ACK) has been received from the called mobile station. If
the
determination made in step 330 is no, the subscriber is marked as not found
(step 332).
Otherwise (steps 326 or 330), an appropriate routing number (for example, a
temporary location directory number (TLDN) or a roaming number) is selected in
step
334. The not found indication or selected routing number is then returned in
step 336,
3 0 and the incoming call is through connected using the returned routing
number to the
called mobile station in step 338.
Returning again to FIGURE 6A, if the known location is within the authorized
area, the process moves to FIGURE 6D. Turning now to FIGURE 6D, paging is
performed for the called mobile station only those particular areas (location
areas or
3 5 cells) of the known location of the called mobile station (step 344). If
the serving
switching node does not serve such an area, the process advances to mark the
subscriber as not found in step 352. A determination is next made in step 346
as to
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whether a paging acknowledgment (ACK) has been received from the called mobile
station. If the determination made in step 346 is no, paging is then
(optionally)
performed for the called mobile station in those particular areas (location
areas or
cells) including the known location where the called mobile station is
authorized to
receive cellular calling service of the known location of the called mobile
station (step
348). A determination is next made in step 350 as to whether a paging
acknowledgment (ACK) has been received from the called mobile station. If the
determination made in step 350 is no, the subscriber is marked as not found
(step 352).
Otherwise (steps 346 or 350), an appropriate routing number (for example, a
temporary location directory number (TLDN) or a roaming number) is selected in
step
354. The not found indication or selected routing number is then returned in
step 356,
and the incoming call is through connected using the returned routing number
to the
called mobile station in step 358.
Returning again to FIGURE 6A, if the known location includes the authorized
area, the process moves to FIGURE 6E. Turning now to FIGURE 6E, paging is
performed for the called mobile station only those particular areas (location
areas or
cells) where the called mobile station is authorized to receive cellular
calling service
(step 370). If the serving switching node does not serve such an area, the
process
advances to mark the subscriber as not found in step 374. A determination is
next
2 0 made in step 372 as to whether a paging acknowledgment (ACK) has been
received
from the called mobile station. If the determination made in step 372 is no,
the
subscriber is marked as not found (step 374). Otherwise, an appropriate
routing
number (for example, a temporary location directory number (TLDN) or a roaming
number) is selected in step 376. The not found indication or selected routing
number
2 5 is then returned in step 378, and the incoming call is through connected
using the
returned routing number to the called mobile station in step 380.
Returning again to FIGURE 6A, if the known location is different from the
authorized area, the process moves to FIGURE 6F. Turning now to FIGURE 6F,
paging is performed for the called mobile station only those particular areas
(location
3 0 areas or cells) where the called mobile station is authorized to receive
cellular calling
service (step 390). If the serving switching node does not serve such an area,
the
process advances to mark the subscriber as not found in step 394. A
determination is
next made in step 392 as to whether a paging acknowledgment (ACK) has been
received from the called mobile station. If the determination made in step 392
is no,
3 5 the subscriber is marked as not found (step 394). Otherwise, an
appropriate routing
number (for example, a temporary location directory number (TLDN) or a roaming
number) is selected in step 396. The not found indication or selected routing
number
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is then returned in step 398, and the incoming call is through connected using
the
returned routing number to the called mobile station in step 400.
Although preferred embodiments of the method and apparatus of the present
invention have been illustrated in the accompanying Drawings and described in
the
foregoing Detailed Description, it will be understood that the invention is
not limited
to the embodiments disclosed, but is capable of numerous rearrangements,
modif cations and substitutions without departing from the spirit of the
invention as
set forth and defined by the following claims.
