Note: Descriptions are shown in the official language in which they were submitted.
CA 02476345 2004-08-31
The present invention relates to a switching station, a
subscriber location information registration method, a
subscriber service information acquisition method, a subscriber
service information registration method, and a subscriber
service information transmission method.
There are two methods for mobility control in mobile
communication : an HLR ( Home Location Register ) method in which
location information and service information of subscribers
to (users) are managed by an apparatus physically separated from
a switching station; and a VLR (Visited Location Register) method
in which subscriber location information and service
information are managed by a VLR in a switching station.
In the case of the VLR method, if the location of a user
cannot be registered after the maximum number of accommodated
users has been reached, neither of call origination and call
termination by the user is allowed.
In connection processing of location registration function,
call origination function and call termination function of the
2o VLR method, when a mobile station moves into an area covered
by a switching station, the mobile station recognizes change
of location area and transmits a location registration signal
to the switching station.
The switching station acquires subscriber service information
about the mobile station from the switching station in whose
coverage area the mobile station has been located ( from the HLR
at the time of the first location regi.stration). Also,
information on the location of the mobile station used at the
- i -
CA 02476345 2004-08-31
time of call termination is registered in the HLR. When the
mobile station makes a call origination, the switching station
performs call origination processing by using subscriber
service information from the VLR. At the time of call
termination, call termination processing is performed by using
the (subscriber) location information from the HLR.
FIG. 1 is a diagram showing an example of a conventional
mobile communication system and an example of processing when
a location registration request is made. Referring to FIG. 1,
to switching stations 11 and 12 have VLR 21 and 22, respectively.
When a mobile station 50 moves from an (service) area 32
of the switching station 12 into an area 31 of the switching
station li having the VLR 21 which has accepted the maximum number
of subscribers, the switching station 11 receives a location
registration (request) signal from the mobile station 50 (in
S11 of FIG. 1) and acquires (in S12) subscriber service
information about the mobile station 50 from the switching
station 12 in whose coverage area the mobile station 50 has been
located. However, no subscriber service information can be
2o newly registered in the VLR 21 (in S13). Therefore location
registration processing ends in failure ( in S14 ) and updating
(registration) of- subscriber location information in an HLR 40
is not performed. zf the subscriber makes call origination in
such a situation, call. origination processing is not normally
performed since the switching station 11 has no service
information about the subscriber on the VLR 21. Call
termination processing also ends in failure since the subscriber
location information in the HLR 40 has not been updated.
- 2 -
CA 02476345 2004-08-31
a
The number of subscribers (subscriber information items)
possible to be registered in the VLR depends on hardware
resources. Also, because the hardware resources are fixedly
assigned, it is not possible to manage inforrnation on dynamically
changing subscribers (users) with flexibility.
Therefore an object of the present invention is to enable
a subscriber to acquire service without dependence on the
accommodation capacity of a management unit which manages
1o subscriber information.
In order to accomplish the above mentioned object, in the
first aspect of the present invention, there is provided a
switching station comprising: means for receiving a location
registration signal from a mobile station; and means for
registering, when the location registration signal is received,
subscriber location information about the mobile station that
has transmitted the location registration signal in a second
management unit managing subscriber information in a case where
no subscriber service information can be newly registered in
2o a first management unit provided for use with the switching
station and managing subscriber information.
Here, the first management unit may be a. VLR.
Here, the second management unit may be an HLR.
In the second aspect of the present invention, there is
provided a switching. station comprising: means for receiving
a call origination signal from a mobile station; and means for
acquiring, when the call origination signal is received,
subscriber service information about the mobile station that
- 3 -
CA 02476345 2004-08-31
a 8
has transmitted the call origination signal from a second
management unit managing subscriber information in a case where
the subscriber service information about the mobile station that
has transmitted the call origination signal is not registered
in a first management unit provided for use with the switching
station and managing subscriber information.
Here, the first management unit may be a VLR.
Here, the second management unit may be an HLR.
In the third aspect of the present invention, there is
Za provided a switching station comprising: means for receiving
a call termination signal to a mobile station; and means for
acquiring, when the call termination signal is received,
subscriber service information about the mobile station
designated as a destination of the call termination signal from
a second management unit managing subscriber information in a
case where the subscriber service information about the mobile
station designated as the destination of the call termination
signal is not registered in a first management unit provided
for use with the switching station and managing subscriber
2o information .
Here, the first management unit may be a VLR.
Here, the second management unit may be an HLR.
In the fourth aspect of the present invention, there is
provided a switching station comprising: means for receiving
a location registration signal from a mobile station; and means
for registering, when the location registration signal is
received, subscriber service information about the mobile
station that has transmitted the location registration signal
CA 02476345 2004-08-31
in a management unit provided for use with another switching
station and managing subscriber information in a case where no
subscriber service information can be newly registered in a
management unit provided for use with the switching station and
managing subscriber information.
Here, the management unit may be a ~JLR.
In the fifth aspect of the present invention, there is
provided a switching station comprising: means for receiving
a call origination signal from a mobile station; and means for
io acquiring, when the call origination signal is received,
subscriber service information about the mobile station that
has transmitted the call origination signal from a management
unit provided for use with another switching station and managing
subscriber information in a case where the subscriber service
information about the mobile station that has transmitted the
call origination signal is not registered in a management unit
provided for use with the switching station and managing
subscriber information:
Here, the management unit may be a VLR.
2o In the sixth aspect of the present invention, there is
provided a switching station comprising: means for receiving
a call termination signal to a mobile station; and means for
acquiring, when the call termination signal is received,
subscriber service information about the mobile station
designated as a destination of the call termination signal from
a management unit provided for use with another switching station
and managing subscriber information in a case where the
subscriber service information about the mobile station
CA 02476345 2004-08-31
designated as the destination of the call termination signal
is not registered in a magement unit provided for use with
the switching station and managing subscriber information.
Here, the management unit may be a VLR.
In the seventh aspect of the present invention, there is
provided a switching station comprising: means for registering,
at a request from another switching station, subscriber service
information in a management unit provided for use with the
switching station and managing subscriber information; and
io means for transmitting the subscriber service information
registered in the management unit to the another switching
station at a request from the another switching station.
Here, the management unit may be a VLR.
In the eighth aspect of the present invention, there is
provided a switching station comprising: means for receiving
a location registration signal from a mobile station; and means
for deleting, when the location registration signal is received,
one of pieces of subscriber service information presently
registered in a first management unit provided for use with the
2o switching station and managing subscriber information, and for
registering subscriber service information of the mobile
station that has transmitted the location registration signal
in the first management unit provided for use with the switching
station, in a case where no subscriber service information can
be newly registered in the first management unit provided for
use with the switching station.
Here, the may further comprises means for registering
subscriber location information about a mobile station in a
- 6 -
CA 02476345 2004-08-31
second management unit managing subscriber information, and
means for receiving subscriber service information about a
mobile station from the second management unit, wherein the
switching station may register, when the location registration
signal is received, subscriber location information about the
mobile station that has transmitted the location registration
signal in a second management unit managing subscriber
information, receive subscriber service information about the
mobile station that has transmitted the location registration
1o signal from the second management unit, delete one of pieces
of subscriber service information presently registered in the
first management unit provided for use with the switching station,
and register the subscriber service information of the mobile
station that has transmitted the location registration signal
in the first management unit provided for use with the switching
station, in a case where no subscriber service information can
be newly registered in the first management unit provided for
use with the switching station.
Here, the second management unit may be an HLR.
2o Here, the switching station may further comprises means for
registering subscriber location information about a mobile
station in a second management unit managing subscriber
information, wherein when the switching station deletes one of
pieces of subscriber service information. presently registered
in the first management unit for use with the switching station,
the switching station nay decide not to delete, from the first
management unit for use with the switching station, subscriber
location information about a mobile station corresponding to
CA 02476345 2004-08-31
the subscriber service information to be deleted, and wherein
when the switching station receives the location registration
signal from the mobile station, the switching station may
register in the second management unit the subscriber location
information about the mobile station registered in the first
management unit for use with the switching station.
Here, the second management unit may be an HLR.
Here, the switching station may further comprises means for
receiving a call origination signal from a. mobile station, and
io means for acquiring subscriber service information about a
mobile station from a second management unit managing subscriber
information, wherein when the switching station receives, after
deleting one of pieces of subscriber service information
presently registered in the first management unit for use with
the switching station, a call origination signal from a mobile
station corresponding to the deleted subscriber service
information, the switching station may acquire the subscriber
service information about the mobile station from the second
management unit, and, if the acquired subscriber service
2o information cannot be newly registered in the first management
unit for use with the switching station, the switching station
may delete one of pieces of subscriber service information
presently registered in the first management unit , and registers
the acquired subscriber service information in the first
management unit for use with the switching station.
Here, the second management unit may be an HLR.
Here, the switching station may further comprises means for
receiving a call termination signal to a mobile station, and
-a-
CA 02476345 2004-08-31
means for acquiring subscriber service information about a
mobile station from a second management unit managing subscriber
information, wherein when the switching station receives, after
deleting one of pieces of subscriber service information
presently registered in the first management unit for use with
the switching station, a call termination signal to a mobile
station corresponding to the deleted subscriber service
information, the switching station may acquire the subscriber
service information about the mobile station from the second
so management unit, and, if the acquired subscriber service
information cannot be newly registered in the first management
unit for use with the switching station, the switching station
may delete one of pieces of subscriber service information
presently registered in the first management unit, and registers
the acquired subscriber service information in the first
management unit for use with the switching station.
Here, the second management unit may be an HLR.
Here, the first management unit may be a VLR.
Here, the switching station may select the mobile station
2o whose subscriber service information is to be deleted, in
consideration of at least one of call origination, call
termination, location registration, and power state of mobile
stations.
Here, the switching station may select, as the mobile
station whose subscriber service information is to be deleted,
a mobile station which has made neither call origination nor
call termination during the longest time period till the present
time.
_ g _
,.
CA 02476345 2004-08-31
Here, the switching station may select, as the mobile
station whose subscriber service information is to be deleted,
a mobile station which has made neither call origination, call
termination nor location registration for predetermined period
of time, or a mobile station whose power state is off.
Here, the switching station may select the- mobile station
whose subscriber service information is to be deleted, in
consideration of communication state of mobile stations.
Here, the switching station may register, when it resisters
io subscriber service information, the subscriber service
information as first type of subscriber service information or
as second type of subscriber service information, and select
the subscriber service information to be deleted from the first
type of subscriber service 'information.
In the ninth aspect of the present invention, there is
provided a subscriber location information registration method
comprising the steps of: receiving, at a switching station, a
location registration signal from a mobile station; and
registering, at the switching station, when the location
2o registration signal is received, subscribes location
information about the mobile station that has transmitted the
location registration signal in a second management unit
managing subscriber information in a case Where no subscriber
service information can be newly registered in a first management
unit provided for use with the switching station and managing
subscriber information.
In the tenth aspect of the present invention, there is
provided a subscriber service information acquisition method
- 10 -
CA 02476345 2004-08-31
comprising the steps of : receiving, at a switching station, a
call origination signal from a mobile station; and acquiring,
at the switching station r when the call origination signal is
received, subscriber service information about the mobile
station that has transmitted the call origination signal from
a second management unit managing subscriber information in a
case where the subscriber service information about the mobile
station that has transmitted the call origination signal is not
been registered in a first management unit provided for use with
io the switching station and managing subscriber information.
In the eleventh aspect of the present invention, there is
provided a subscriber service information acquisition method
comprising the steps of: receiving, at a switching station, a
call termination signal to a mobile station; and acquiring, at
the switching station, when the call termination signal is
received, subscriber service information about the mobile
station designated as a destination of the call termination
signal from a second management unit managing subscriber
information in a case where the subscriber service information
2o about the mobile station designated as the destination of the
call termination signal is not registered in a first management
unit provided for use with the switching station and managing
subscriber information.
In the twelfth aspect of the present invention, there is
provided a subscriber service information registration method
comprising the steps of : receiving; at a first switching station,
a location registration signal from a mobile station; and
registering, at the first switching station, when the location
- 11 -
CA 02476345 2004-08-31
registration signal is received, subscriber service information
about the mobile station that has transmitted the location
registration signal in a management unit provided for use with
a second switching station and managing subscriber information
in a case where no subscriber service information can be newly
registered in a management unit provided for use with the first
switching station and managing subscriber information.
In the thirteenth aspect of the present invention, there
is provided a subscriber service information acquisition method
1o comprising the steps of : receiving, at a first switching station,
a call origination signal from a mobile station; and acquiring,
at the first switching station, when the call origination signal
is received, subscriber service information about the mobile
station that has transmitted the call origination signal from
a management unit provided for use with a second switching
station and managing subscriber information in a case where the
subscriber service information about the mobile station that
has transmitted the call origination signal is not registered
in a management unit provided for use with the first switching
2o station and managing subscriber information.
In the fourteenth aspect of the present invention, there
is provided a subscriber service information acquisition method
comprising the steps of : receiving; at a first switching station,
a call termination signal to a mobile station; and acquiring,
at the first switching station, when the call termination signal
is received, subscriber service information about the mobile
station designated as a destination of the call termination
signal from a management unit provided for use with a. second
i2 -
CA 02476345 2004-08-31
switching station and managing subscriber information i.n a case
where the subscriber service information about the mobile
station designated as the destination of the call termination
signal is not registered in a management unit provided for use
with the first switching station and managing subscriber
information .
In the fifteenth aspect of the present invention, there is
provided a subscriber service information transmission method
comprising the steps of: registering, at a first switching
to station, at a request from a second switching station, subscriber
service information in a management unit provided for use with
the first switching station and managing subscriber
information; and transmitting, at the first switching station,
the service information .registered in the management unit to
the second switching station at a request from the second
switching station.
In the sixteenth aspect of the present invention, there is
provided a subscriber service information registration method
comprising the steps of : receiving, at a switching station, a
20 location registration signal from a mobile station; and deleting,
at the switching station, when the location registration signal
is received, one of pieces of subscriber service information
presently registered in a first management unit provided for
use with the switching station and managing subscriber
information, and registering, at the switching station,
subscriber service information of the mobile station that has
transmitted the location registration signal in the first
management unit provided for use with the switching station,
- 13 -
CA 02476345 2004-08-31
in a case where no subscriber service information can be newly
registered in the first management unit provided for use with
the switching station.
According to the above mentioned configurations, a
subscriber can acquire service without dependence on the
accommodation capacity of a management unit which manages
subscriber information.
The above and other objects, effects, features and
advantages of the present invention will become more apparent
la from the following description of embodiments thereof taken in
conjunction with the accompanying drawings.
FZG. 1 is a diagram showing an example of a configuration
of a conventional mobile communication system and an example
of processing when a location registration request is made;
FIG. 2 is a diagram showing an example of a configuration
of a mobile communication system and an example o.f processing
when a location registration request is made in the first
embodiment of the present invention;
2o FIG. 3 is a diagram showing an example of a configuration
of a switching station;
FIG. 4 is a diagram showing an example of processing when
a call origination request is made in the first embodiment of
the present invention;
FIG. 5 is a diagram showing an example of processing when
a call termination request is made in the first embodiment of
the present invention;
- 14 -
CA 02476345 2004-08-31
FIG. 6 is a diagram showing an example of processing when
a location registration request is made in the second embodiment
of the present invention;
FIG. 7 is a diagram showing an example of processing when
a call origination request is made in the second embodiment of
the present invention;
FIG. 8 is a diagram showing an example of processing when
a call termination request is made in the second embodiment of
the present invention;
to FIG . 9 is a diagram showing an example of processing when
a location registration request is made in the third embodiment
of the present invention;
FIG. 10 is a diagram showing an example of processing when
a location registration request is made in the third embodiment
of the present invention;
FIG. 11 is a diagram showing an example of processing when
a call origination request is made in the third embodiment of
the present invention;
FIG. 12 is a diagram showing an example of processing When
2o a call termination request is made in the third embodiment of
the present invention;
FIG. 13 is a diagram for explaining attach state and detach
state;
FIG. 14 is a diagram for explaining an example of selecting
a mobile station whose subscriber service information is to be
deleted;
- 15 -
CA 02476345 2004-08-31
FIG. 15 is a diagram showing an example of inquiring
communication state of a service control unit , when the service
control unit manages the communication state;
FIG. 16 is a diagram for explaining an example of selecting
a mobile station whose subscriber service information is to be
deleted;
FIG. Z7 is a diagram showing an example of preparing an area
possible to be overwritten and an area impossible to be
overwritten in a subscriber management memory of VLR; and
io FIG. 18 is a diagram showing an example of processing
corresponding to the example of processing shown in FIG . 9 when
a location registration request is made, in a case where
subscriber service information is acquired from an HLR.
Embodiments of the present invention will be described in
detail with reference to the accompanying drawings.
(FIRST EMBODIMENT)
FIG. 2 is a diagram showing an example of a configuration
of a mobile communication system and an example of processing
2o when a location registration request is made in the first
embodiment of the present invention. Referring to FIG. 2,
switching stations 111 and 112 have VLRs 121 and 122,
respectively. The VLRs 121 and 122 may be provided inside or
outside the switching stations 111 and 112. The VLRs 121 and
122, which are management units respectively used by the
switching stations in management of subscriber information,
manage ubscriber information such as subscriber service
information and subscriber location information . An HLR 140 is
- 16 -
CA 02476345 2004-08-31
a management unit which is provided independently of switching
stations, and which manages subscriber information.
FIG. 3 is a diagram showing an example of a configuration
of a switching station . The switching station 111 has a control
portion 191 which performs various kinds of control, a storage
portion 192 which stores various processing procedures, data,
etc. , and a communication portion 193. A VLR 121 may be provided
inside or outside the switching station 111, as are those
described above. The control portion 191 performs
io communication with other switching stations , mobile stations ,
HLRs , VLRs , etc . , through the communication portion 193 and other
switching stations , base stations or the like . The VLR 121 has
a subscriber management memory 180 which stores subscriber
information. Other switching stations (the switching station
112 etc.) can have the same configuration as the switching
station 111.
Referring again to F:CG. 2, when a mobile station 150 moves
from an area 132 of the switching station 112 into an area 131
of the switching station 111 having the VLR 121 which has accepted
2o the maximum number of subscribers, the switching station 111
receives a location registration signal from the mobile station
150 ( in S21 of FIG. 2 ) and acquires ( in S22 ) subscriber service
information about the mobile station 150 from the switching
station 112 in whose coverage area the mobile station 150 has
been located. Here, no subscriber service information can be
newly registered in the VLR 121 ( in S23 ) . However, the switching
station 111 registers subscriber location information about the
mobile station 150 in the FiLR 140 (in S24), as it stores
17 -
CA 02476345 2004-08-31
corresponding information in the VLR 121 in the case where
subscriber service information can be registered in the VLR 121.
The switching station 111 normally completes location
registration processing(in S25). The switching station 111can
store in the storage portion 192 or the VLR 121, information
of the mobile station 150 as a mobile station whose subscriber
service information is not registered in the VLR 12:1. Thereby,
the switching station 111 can recognize that subscriber service
information of the mobile station 150 is not registered in the
io VLR 121, when call origination from the mobile station 150 or
call termination to the mobile station 150 occurs later.
FIG. 4 is a diagram showing an example of processing when
a call origination request is made in the present embodiment.
Thereafter, when a call origination signal is transmitted from
the mobile station 250 to the switching station 111 ( in S31 of
FIG . 4 ) , the switching station 111 acquires subscriber service
information about the mobile station 150 from the H.LR 140 (in
step S32 ) since the VLR 121 has no subscriber service information
about the mobile station 150. Then the switching station 111
zo normally performs call origination connection processing (in
S33).
FIG. 5 is a diagram showing an example of processing when
a call termination request is made in the present embodiment.
When a call termination request is made to the mobile station
150 , call termination processing can also be performed normally
since the subscriber location information about the mobile
station 150 has been correctly updated in the HLR 140. When a
call termination signal to the mobile station 150 is transmitted
- i8 -
CA 02476345 2004-08-31
to the switching station lIl ( in S41 of FIG . 5 ) , the switching
station 111 acquires the subscriber service information about
the mobile station 150 from the HLR 140 ( in S42 ) and performs
call termination processing (in S43).
(SECOND EMBODIMENT)
The arrangement may alternatively be such that in a case
where a switching station cannot register subscriber service
information in its own VLR, it registers the subscr:Lber service
information in the VLR of another switching station instead of
to acquiring the subscriber service information from 'the HLR 140.
'°Another switching station°' may be an adjacent switcriing
station,
a switching station in whose coverage area the mobile station
has been located, a switching station having a la=rge capacity
VLR, etc. A first candidate, a second candidate, and so on for
'°another switching station" may be determ~.ned in advance with
respect to each switching station. When one switching station
requests another switching station to register subscriber
service information, the requested switching station registers
the subscriber service information. Each switching station
2o stores information that in which VLR the subscriber service
information of the mobile station was stored, if it had
subscriber service information registered by the another
switching station in a situation where it could not register
the subscriber service information of the mobile station in its
own VLR. Thereby, the switching station can recognize the VLR
in which the subscriber service information is stored, when call
origination from the mobile station or call termination to the
mobile station occurs later.
- is -
CA 02476345 2004-08-31
FIG. 6 is a diagram showing an example of processing when
a location registration request is made in the second embodiment
of the present invention. When the mobile station 150 moves from
the area 132 of the switching station 112 into the area 131 of
the switching station 111 having the VLR 121 which has accepted
the maximum number of subscribers, the switching station 111
receives a location registration signal from the mobile station
150 ( in S51 of FIG. 6 ) and acquires ( in S52 ) subscriber service
information about the mobile station 150 from the switching
io station 112 in whose coverage area the mobile station 150 has
been located. Here, no subscriber service information can be
newly registered in the VLR 221 ( in S53 ) . However, the switching
station 111 registers subscriber location information about the
mobile station 150 in the HLR 140 (in S54), as it stores
corresponding information in the VLR 121 in the case where
subscriber service information can be registered in the VLR 121.
Further, the switching station 111 registers subscriber service
information about the mobile station 150 in another switching
station ( in a VLR 123 of a switching station 113 in this example )
20 (in S55), and normally completes location registration
processing (in S56).
FIG . 7 is a diagram showing an example of processing when
a call origination request is made in the present embodiment.
When a call origination signal is transmitted from the
mobile station to the switching station ( in S61 of FIG. 7 ) after
registration in the another VLR, the switching station acquires
subscriber service information about the mobile station from
the another VLR (in step S62) and performs call origination
- 2U -
I
CA 02476345 2004-08-31
connection processing (in S63). When the switching station
requests the another switching station to transmit the
subscriber service information, the another switching station
transmits the subscriber service information to the switching
station.
FIG . 8 is a diagram showing an example of processing when
a call termination request is made in the present embodiment.
When a call termination signal is transmitted to the mobile
station (in S71 of FIG. 8) after registration in the another
io switching station, the switching station acquires the
subscriber service information about the mobile station from
the another switching station (in S72) and perfoa:~ms call
termination processing (in S73). When the switching station
requests the another switching station to transmit the
subscriber service information, the another switching station
transmits the subscriber service information to tree switching
station.
(THIRD EMBODIMENT)
As an alternative to the method of using the method of
2o acquiring subscriber service information from the: HLR 140 or
the method of registering subscriber service information in
another switching station, a method may be used in which a
switching station deletes one of pieces of subscriber service
information presently registered in its own VLR t;o enable
registration of subscriber service information about a mobile
station that has transmitted a location registration signal in
its own VLR.
- 21 -
CA 02476345 2004-08-31
FIG . 9 is a diagram showing an example of processing when
a location registration request is made in' the third embodiment
of the present invention. When the mobile station 150 moves from
the area 132 of the switching station 112 into the area 131 of
the switching station 111 having the VLR 121 which has accepted
the maximum number of subscribers, the switching station 111
receives a location registration signal from the mobile station
150 ( in S81 of FIG. 9 ) and acquires ( in S82 } subscri.ber service
information about the mobile station 150 from the. switching
1o station 112 in whose coverage area the mobile station 150 has
been located. In this situation, no subscriber service
information can be newly registered in the VLR 121.. However,
the switching station I11 deletes one of pieces of subscriber
service information presently registered in the VLR 121 ( assumed
to be subscriber service information about a mobile :>tation 151 )
and registers the subscriber service information about the
mobile station 150 in the VLR 121 (in S83). The switching
station 111 then registers subscriber location information
about the mobile station 150 in the HLR 140 ( in S84 ) , and normally
2o completes location registration processing (in 585).
The arrangement may be such that when one piece of subscriber
service information presently registered in the VLR of the
switching station is deleted, deletion from the VLR of the
subscriber location information about the mobile station
corresponding to the subscriber service information to be
deleted is inhibited.
- zz -
CA 02476345 2004-08-31
FIG. 10 is a diagram showing an example of processing when
a location registration request is made in the present
embodiment.
Thereafter, when a location registration signal is received
from the mobile station whose subscriber service information
has been deleted { in S91 of FIG. 10 ) , the switching station can
acquire the subscriber location information about the mobile
station from its own VLR (in S92), and register it in the HLR
140 (in S93). Then, the switching station normally completes
to location registration processing (in S94).
FIG. 11 is a diagram showing an example of processing when
a call origination request is made in the present embodiment.
In a case where the switching station receives a call
origination signal from the mobile station whose subscriber
service information has been deleted ( in 5101 of FIG . 11 ) , the
switching station acquires the subscriber service information
about the mobile station from the HLR 140 (in S102). If the
switching station cannot newly register the acquired subscriber
service information in its own VLR, it may delete one of pieces
20 of subscriber service information presently registered in its
own VLR and register the acquired subscriber service information
in its own VLR ( in S103 ) . Then the switching station performs
call origination connection processing (in S104).
FIG. 12 is a diagram showing an example of processing when
a call termination request is made in the present embodiment .
In a case where the switching station receives a call
termination signal to the mobile station whose subscriber
service information has been deleted (in 5121 of FIG. 12), the
- 23 -
CA 02476345 2004-08-31
switching station acquires the subscriber service information
about the mobile station from the HLR 140 (in S122). If the
switching station cannot newly register the acquired subscriber
service information in its own VLR, it may delete one of pieces
of subscriber service information presently registered in its
own VLR and register the acquired subscriber service information
in its own VLR ( in S123 ) . Then the switching station performs
call termination processing (in S124).
In the steps S83 5103 and 5123, the mobile station whose
to subscriber service information is to be deleted can be selected
in consideration of call origination, call termination,
location registration, power state, etc. of mobile stations.
For example, as the mobile station whose subscriber service
information is to be deleted, a mobile station which has made
neither call origination nor call termination during the longest
time period till the present time can be selected.
Also, for example, as the mobile station whose; subscriber
service information is to be deleted, a mobile station in detach
state, i.e., a mobile station which has made neither call
20 origination, call termination nor location registration for
predetermined period of time, or a mobile station whose power
state is off can be selected.
The second example will be described in detail.
FIG. 13 is a diagram for explaining attach state and detach
state. When location registration is performed for a mobile
station, a switching station makes the state of the mobile
station attach state. Thereafter, the switching station finds,
using a timer #2 (mobile not reachable timer) ~ a mobile station
- 24 -
CA 02476345 2004-08-31
which has made neither call origination, call teranination nor
location registration for predetermined period of time in the
area of the switching station, and makes the state of the found
mobile station detach state. The switching station also makes
the state of a mobile station detach state, when it receives
from the mobile station a detach signal indicating that the power
has become off. When a Imobile station whose stage is detach
state makes call origination, call termination or location
registration, the switching station makes the state of the mobile
io station attach state. A mobile station periodically (for
example , every three hours ) transmits , using a timer # 1 ( periodic
routing update timer), a location registration signal to the
switching station to request location registration. Attach
state and detach state can be represented, for example, by using
off and on of a (detach) flag.
FIG. 14 is a diagram for explaining an example of selecting
a mobile station whose subscriber service information is to be
deleted. In FIG. 14, the timer #2 column shows, for each mobile
station ( subscriber ) , elapsed time since the last time the mobile
2o station made call origination, call termination or location
registration. The priority of FIG. 14 is prioritvy (rank) for
each mobile station to be selected as the mobile station whose
subscriber service information is to be deleted. In the example
of FIG. 14, since the state of mobile stations A and B is attach
state and the state of mobile stations C and D is detach state,
the mobile stations C and D have higher priority than the mobile
stations A and B. Between mobile stations having the same state,
a mobile station having longer elapsed time has higher priority.
- 25 -
CA 02476345 2004-08-31
a
Therefore, the mobile station D has higher priority than the
mobile station C, and the mobile station D has higher priority
than the mobile station
The mobile station whose subscriber service information is
to be deleted can be selected in consideration of communication
state of mobile stations. In general, when subscriber service
information is deleted, and if the mobile station corresponding
to the deleted subscriber service information is in
communication, the communication is disconnected
1o unconditionally. Therefore, as the mobile station whose
subscriber service information is to be deleted, a mobile station
which is not in communication can be selected. That is, when
a switching station intends to select a mobile station as the
mobile station whose subscriber service information is to be
deleted, and if the mobile station is in communication, the
switching station can select another mobile station as the mobile
station whose subscriber service information is to be deleted.
Communication state of each mobile station can be managed, for
example, at VLR or a service control unit performing control
2o regarding call processing and service to subscriber, by having
management table of communication state.
FIG. 15 is a diagram showing an example of inquiring
communication state of a service control unit , when the service
control unit manages the communication state. In this
embodiment, a service control unit is provided for each switching
station. The switching station 111 inquires communication
state of each mobile station of a service control unit 161,
receives its response from the service control unit 161, and
- 26 -
CA 02476345 2004-08-31
selects in consideration of the response, the mobile station
whose subscriber service information is to be deleted.
FIG. 16 is a diagram for explaining an example of selecting
a mobile station whose subscriber service information is to be
deleted. In the example of FIG. 16, since the communication
state of mobile stations A and D is not in communication and
the state of mobile stations B and C is in communication, the
mobile stations A and D have higher priority than the mobile
stations B and C. That is, one of the mobile stations A and D
io is selected as the mobile station whose subscriber service
information is to be.deleted.
The switching station registers, when it resisters
subscriber service information, the subscriber service
information as subscriber service information possible to be
overwritten (subscriber service information possible to be
deleted when the maximum number of accommodated users has been
reached in VLR) or as subscriber service information impossible
to be overwritten, and selects the subscriber service
information to be overwritten from (pieces of) subscriber
2o service information possible to be overwritten. for example,
it is possible to register subscriber service information of
a subscriber who frequently uses communication as subscriber
service information impossible to be overwritten, and register
subscriber service information of a subscriber who rarely uses
communication as subscriber service information possible to be
overwritten.
FIG. 17 is a diagram showing an example of preparing an area
possible to be overwritten and an area impossible to be
- 27 -
CA 02476345 2004-08-31
overwritten in a subscriber management memory of VLR. The
switching station 111 registers subscriber service information
possible to be overwra.tten in an area 181 possible to be
overwritten, and registers subscriber service information
impossible to be overwritten in an area 182 impossible to be
overwritten.
(OTHERS)
In the foregoing description, a case where subscriber
service information about a mobile station is acquired from a
~o switching station in whose coverage area the mobile station has
been located is described. However, the subscriber service
information can be acquired from HLR when location registration
other than the first location registration is made as well as
when the first location registration is made.
FIG. l8 is a diagram showing an example of processing
corresponding to the example of processing shown in FIG . 9 when
a location registration request is made, in a case where
subscriber service information is acquired from an HLR. When
the switching station 111 having the VLR 121 which has accepted
2o the maximum number of subscribers receives a location
registration signal from the mobile station 150 (in 5111 of FIG.
18), the switching station 111 registers subscriber location
information about the mobile station 150 in the HLR 140, and
receives subscriber service information about the: mobile
station 150 from the HLR 140 (in S112). Then, the switching
station 111 deletes one of pieces of subscriber service
information presently registered in the VLR 121 and registers
the subscriber service information about the mobile station 150
- 28 -
CA 02476345 2004-08-31
in the VLR 121 (in S113). In this way, location registration
processing is normally completed (in S114).
According to the present invention, as described above, a
subscriber can acquire service without dependence on the
accommodation capacity of a management unit which manages
subscriber information. That is, the system allows location
registration, call origination and call termination processing
for subscribers as an excess over the maximum number of
accommodated subscribers, and more comfortable communication
environment can be provided to subscribers by effectively using
VLR memories.
The present invention has been described in detail with
respect to preferred embodiments, and it will now be apparent
from the foregoing to those skilled in the art that changes and
modifications may be made without departing from the invention
in its broader aspects, and it is the intention, therefore, in
the appended claims to cover all such changes and modifications
as fall within the true spirit of the invention.
- 29 -
