Note: Descriptions are shown in the official language in which they were submitted.
219~56
-
Starting a short message transmission in a cellular
communication system
Field of the Invention
The present invention relates to a method for
starting a short message transmission in a cellular
communication network, a corresponding cellular
communication system, and a cellular communication
system subscriber location register, in which method the
subscriber location register stores information-on the
fact that at least one short message service center
stores short messages to be transmitted to a subscriber,
to whom they cannot be transmitted for the time being,
and the subscriber location register of the subscriber
transmits to said at least one short message service
center a short message transmission starting message
when it is possible again to transmit short messages to
the subscriber.
Background of the Invention
Today, different cellular communication or
mobile telephone systems are used and planned, in which
systems the geographical area covered by a system is
divided into smaller separate radio areas, i.e. cells,
in such a manner that when located in a cell, a radio
phone or a mobile phone communicates with the fixed
network via the fixed radio station located in the cell.
The mobile phones included in the system may freely move
within the system area from a cell into another. One of
these systems is the digital mobile phone system GSM
(Global System for Mobiles).
As regards cellular communication networks, it
is known practice to transmit short messages via a short
message service center separate from the cellular
communication network. One of these systems transmitting
and forwarding short messages is described in ETSI GSM
- 219535G
system recommendation "GSM 03.40, February 1992,
Technical Realization of Short Message Services Point
to Point, ETSI/PT". It describes the connection of a
short message service center to the mobile exchange of
a cellular communication network and the operation of
this short message service center when the center
transmits and forwards short messages from outside the
cellular communication network and from a cellular
communication network subscriber (subscriber A) to
another network subscriber (subscriber B), or to a means
of communication which is capable of receiving and/or
transmitting short messages and which is located outside
the network.
When a short message service center attempts
to transmit a short message to a subscriber B, and the
subscriber B is not reachable, a Messages-Waiting-Data-
List according to the GSM recommendation 03.40, i.e. an
MWD list, is established in the home location register,
in which list are stored, subscriber B-specifically, the
addresses of those short message service centers which
store short messages to be delivered to subscribers B.
Accordingly, when the subscriber B registers in the
network, i.e. it is possible to transmit a short message
to the mobile phone of the subscriber B, the visitor
location register in the area of which the subscriber
B registers i-tself transmits a notification of the
arrival of the subscriber B in the network to the home
location register of the subscriber B. The home location
register of the subscriber B, i.e. the subscriber
location register, thus starts to transmit
notifications, i.e. short message transmission starting
messages, or, Alert messages (Alert), to the short
message service centers presented in the Messages-
Waiting-Data-List of said subscriber, said starting
messages informing the short message service centers
- 2195356
that the subscriber B has become-active in the cellular
communication network area and that it is worth
attempting to transmit a short message to the mobile
phone of the subscriber B. A situation of this type may
occur for instance when the subscriber has switched off
her mobile phone for the night and switches it on in the
morning, or correspondingly, if the subscriber uses a
mobile phone at work and switches on her mobile phone
at the beginning of working hours.
A typical problem of the prior art solutions
is that-~he transmission capacity of short messages from
short message service centers to a subscriber is very
restricted. The transmission capacity on the radio path
is only 10 - 100 bytes/second, which is significantly
less than what is used for instance in modem
communication between computers. However, it has been
required that short message transmissions should be
capable of forwarding even electronic mail-type messages
to subscribers. The transmission capacity of short
message~ is typically a crucial characteristic
especia~ly in the situations described above. Thus, when
a subscriber B has suddenly become reachable, attempts
are made to transmit to the subscriber B a great number
of short messages, which have been stored in possibly
several short message service centers. The short
messages suddenly transmitted to the subscriber thus
congest the short message reception of the subscriber,
i.e. the mobile phone, and possibly also the
transmission link or radio path to the subscriber. As
a result of the congestion, it may occur that a new and
possibly urgent short message to be transmitted to the
subscri--ber will not reach its destination quickly
enough, because the short message reception of the
subscriber, i.e. the mobile phone, is congested.
Important short messages are thus lost, in a manner of
219~i356
speaking, in the multitude of less important, queuing
short messages.
Another problem of the prior art solutions,
occurring when short messages can be transmitted again
to the subscriber B after a pause, is that the short
messages intended for said subscriber B thus arrive in
succession to the subscriber B and thus disturb the user
of the subscriber station with their arrival and
possible audio signals connected to the arrival for a
very long time, i.e. as long as said subscriber has
short messages to receive. This disturbing period may
last for an extremely long time due to the low
transmission speed of the short message-transmitting
radio path, according to the GSM specification, and to
the fact that the subscriber has to receive all short
messages. The aggravation of the subscriber is naturally
added to by the fact that the subscriber has no
possibility of selecting from the short messages those
short messages the transmitters, i.e. short message
service centers, of which said subscriber considers the
most important.
Yet another problem of the prior art solutions
is that when operating according to them, the subscriber
B cannot select or eliminate the arriving short messages
in a desired manner but the subscriber B has to receive
all the short messages transmitted to it.
One prior art method for starting a short
message transmission in a cellular communication system,
a cellular communication system, and a cellular
communication system subscriber location register have
been disclosed in Finnish Patent Application 924,198,
which corresponds to International Patent Application
PCT/FI93/00373.
'-- 2195356
Description of the Invention
An object of the present invention is to
obviate a problem caused by an insufficient transmission
capacity in transmitting short messages from short
message service centers to subscribers and by the fact
that the short messages transmitted to a subscriber are
congested when the subscriber has suddenly entered a
state in which it can be transmitted short messages. In
addition to this, a problem is caused by the fact that
important short messages to be delivered to the
subscribers remain undelivered or arrive too late,
because they are transmitted only when the subscriber
has received the congested short messages, which had
been transmitted first.
In addition to the above, an object of the
invention is to obviate a problem caused by the fact
that the subscriber cannot select the short messages
transmitted to him and cannot thus limit the number of
the short messages transmitted to him.
Furthermore, an object of the invention is to
ensure that important short messages reach their
destination when there are suddenly a great number of
short messages to be transmitted to the subscriber.
This new type~of method for starting a short
message transmission in a cellular communication system
is characterized in that information on the conditions
on which the short message service center is transmitted
short message transmission starting messages is
maintained short message service center- and subscriber-
specifically in the subscriber location register.
The cellular communication system disclosed in
the present patent application comprises a subscriber;
at least one short message service center for
transmitting short messages to the subscriber via the
cellular communication network and for storing short
-- 21953S6 - -
messages when the subscriber is not reachable; the
subscriber location register of the subscriber,
containing information on the fact that said at least
one short message service center stores short messages
to be transmitted to the unreachable subscriber, said
subscriber location register comprising means for
transmitting a short message transmission starting
message to said at least one short message service
center when it is possible again to transmit short
messages to the subscriber.
The cellular communication system of the
invention is characterized in that the subscriber
location register comprises a database, in which
information on the conditions on which the short message
service center is transmitted short message transmission
starting messages is maintained short message service
center- and subscriber-specifically.
The subscriber location register of a cellular
communication system disclosed in the present patent
application comprises means for transmitting a short
message transmission starting message to at least one
short message service center. The subscriber location
register of the invention is characterized in that the
subscriber location register comprises a database, in
which information on the conditions on which the short
message service center is transmitted short message
transmission starting messages is maintained short
message service center- and subscriber-specifically.
The invention is based on the idea that in the
3 0 subscriber location register o~ the cellular
communication system, for instance in a home location
register (HLR), information is maintained in a database
on the conditions, i.e. when, in which order, and for
the subscriber situated in which location, on which a
short message service center storing short messages
21953~6
intended for the subscriber is transmitted short message
transmission starting messages, i.e. Alert messages.
This brings about a situation where said subscriber
location register transmits the short message
transmission starting messages, i.e. Alert messages,
concerning a particular subscriber B, i.e. the receiver,
to those short message service centers which are
actually desired to transmit short messages to the
subscriber B. Starting messages are selectively
transmitted to short message service centers on the
basis ~f said maintained information in such a manner
that starting messages are transmitted to only those
(first) short message service centers which are desired
to transmit short messages. Correspondingly, starting
messages are not transmitted to those (second) short
message service centers which are not desired to
transmit short messages, even if those (second) short
message service centers contain short messages to be
transmitted to the subscriber B. The idea of the
invention is to prioritize th-e transmission of short
message transmission starting messages in such a manner
that when it is possible to transmit short messages to
a subscriber after a pause, the subscriber is first
transmitted important starting messages only.
An advantage of this type of method for
starting a short message transmission in a cellular
communication system, cellular communication system and
cellular communication system subscriber location
register is that the method of the invention prevents
the congestion of short messages on the radio path when
it is possible again to start transmitting short
messages to a subscriber after a pause.
Another advantage of the invention is that by
means thereof, it is possible to avoid a situation where
the mobile station of a subscriber has to receive in
219~356
succession a large number of short messages stored in
the network with the result that the user of the
subscriber station is disturbed and gets weary of
receiving a large number of short messages in
succession.
Yet another advantage of the invention is that
it enables a subscriber to select those short messages
which the subscriber desires to receive at her own
subscriber station, i.e. mobile station.
A further advantage of the invention is that
it provides a subscriber B receiving short messages with
a possibility to restrict the number of the short
messages it receives, for instance on the basis of which
short message service center has transmitted or
forwarded said short message.
Furthermore, an advantage of the invention is
that it offers a subscriber a possibility of dividing
short messages on the basis of her own geographical
location into those which said subscriber desires to
receive within a certain period of time, and
correspondingly into those which the subscriber does not
want to receive.
Brief Description of the Figures
In the following, the invention will be
described in more detail with reference to the
accompanying drawings, in which
Figure 1 is a schematic illustration of a
cellular communication system in which the method and
mobile exchange of the invention can be used,
Figure 2 shows the hierarchy of the subscriber
data of a subscriber home location register, i.e. a
subscriber location register,
Figure 3 shows a block diagram of the cellular
communication system of the invention and the subscriber
location register thereof,
2195356
Figure 4 shows a signalling diagram of a
situation where a subscriber has become reachable, and
only part of the short message transmission starti-
messages are transmitted,
Figure 5 shows a signalling diagram of a
situation where a subscriber has become reachable, and
short message transmission starting messages are
transmitted to only certain short message service
centers,
Figure 6 shows a signalling diagram of a
situation where a subscriber has become reachable, and
short message transmission starting messages are
transmitted to only certain short message service
centers, depending on the subscriber's location,
Figure 7 shows a signalling diagram of a
situation where a subscriber requests and controls the
transmission of short message transmission starting
messages.
Detailed Description of the Invention
In the following, the method of the invention
will be described as applied in~the digital GSM mobile
telephone system, which is the preferred field of
application of the invention. The method of the
invention can, however, also be applied in other radio
systems of a similar type or in adaptations of the GSM
system. The basic structure and facilities of the GSM
mobile telephone system are known to ones skilled in the
art and defined relatively precisely in the GSM system
specifications,' especially in "GSM ~ecommendations
01.02; 11.30; 11.31; 11.32; 03.40".
A GSM network, which is shown in Figure 1,
usually comprises one home location register HLR, which
is a database in which the data of a mobile phone, such
as the location data, is permanently stored. The home
location register performs basically the same tasks as
2195356 - '~
,
the subscriber location register of the invention. The
system also comprises several visitor location registers
VLR, of which there are one or more for one exchange
area. A visitor location register VLR iS a database in
which the data of a mobile phone is stored for the
period that the mobile phone visits the VLR area, i.e.
the location area of the mobile phone. The VLR knows the
location of the mobile phone MS with an accuracy of one
location area. As for the HLR, it knows which VLR the
mobile phone MS is visiting and gives mobile phone MS-
terminating calls routing information to the telephone
network, i.e. the VLR address of the location area of
the subscriber B. The HLR obtains the necessary routing
information from the VLR. The HLR and VLR have only a
signalling connection with the other components of the
mobile telephone network. In the system according to
Figure 1, each exchange area has its own visitor
location register VLR, which is connected to the mobile
or radio telephone exchange MSC of said exchange area.
In the solution shown in the figure, two exchange areas
are illustrated, one comprising a mobile exchange MSC1
and a visitor location register VLRl, and the other
comprising a mobile exchange MSC2 and a visitor location
register VLR2. Under both exchange areas there are one
or more location areas, and in each location area the
traffic is controlled by a base station controller
(BSC), which controls several fixed radio stations, i.e.
base transceiver stations (BTS). Each of the above-
mentioned radio cells comprises one base station BTS,
and one base station controller BSC serves several
cells. A mobile phone MS located in a cell establishes
à two-way radio connection with the base transceiver
station BTS of said cell. There are both a signalling
connection and speech channels between the base station
controller BSC and the mobile exchange MSC.
2195356 .
Correspondingly, under the other exchange area MSC2 is
a location area with a base station controller BSC2 and
base stations BTS3 and BTS4.
A GSM network is usually connected to other
networks, such as a public-switched telephone network
PSTN, another mobile telephone network PLMN, packet-
switched public data network PSPDN, ISDN network ISDN
or short message service center SC, via a certain mobile
exchange referred to as a gateway exchange GMSC. One or
more (all) mobile exchanges of the network can act as
a gateway exchange GMSC. From the gateway exchange GMSC
it is possible to switch a speech channel connection to
any other mobile exchange MSC of the network. The
gateway exchange GMSC also has a signalling connection
with the home location register HLR. As for the home
location register HLR, it has a signalling connection
with the visitor location registers VLR. Alternatively,
an exchange of another data transmission system, for
instance an ISDN exchange, can also act as a gateway
exchange. Figure 1 also shows several short message
service centers SC, which transmit a short message via
the cellular communication network to the mobile phone
MS of the subscriber B and which, during the time the
subscriber is not reachable, store the short messages
intended to be transmitted later to the subscriber.
Figure 2 shows the hierarchy of the subscriber
data of a subscriber home location register, i.e. a
subscriber location register. The subscriber data is
stored on the basis of the subscriber's international
mobile subscriber identity IMSI in the home location
register of the subscriber as subscriber-specific
records, in which are stored the supplementary services
ordered by the subscriber in addition to the basic
service of the subscriber. The basic services of a
subscriber are the normal telephone service, short
219535~ -
message transmission and reception services and
different data transmission services. The supplementary
services of a subscriber include for instance call
forwarding and call restriction services and the call
waiting service. One basic service of the subscriber can
correspond to one MSISDN number msisdn of the
subscriber, i.e. the "directory number" of a certain
teleservice of the subscriber. In the GSM system, it is
possible to transmit short messages to a subscriber on
the basis of any directory number, i.e. the
corresponding basic service of the subscriber, or, the
MSISDN number, of the same subscriber. Each MSISDN
number of the subscriber and the basic service
corresponding thereto has its own MWD ~Messages-Waiting-
Data) list, which stores the addresses Scl, Sc2 of those
short message service centers SC which have attempted
to transmit short messages to the subscriber basic
service indicated by said MSISDN number (directory
number), but the transmission has failed for some
reason, for instance because the subscriber has not been
reachable due to the fact that the terminal equipment
of the subscriber has been located outside the coverage
area of a radio network base station, i.e. in a shadow
area, or due to the fact that the terminal equipment of
the subscriber has been switched off.
- Figure 3 shows a subscriber MS connected to the
cellular communication system via a base station BTS1,
BTS2, base station controller BSC, and the mobile
exchange VMSC/VLR of the location area of the
subscriber. One or more short message service centers
SC1, SC2, SC3 store short messages to be transmitted to
the subscriber MS. The short message service centers are
connected to the cellular communication network via a
gateway exchange GMSC/IWMSC. The visitor location
register VLR of the location area of the subscriber
~19~35~
stores information (Messages-Waiting-Flag) on the fact
that a short message service center SC stores short
messages to be transmitted to the subscriber. A
subscriber location register 10, which corresponds to
a home location register HLR in the GSM system, contains
an HLR function block 3. The home location register of
the invention also comprises a database in which
information is maintained, short message service center-
and subscriber-specifically, on the conditions on which
the short message service center storing short messages
of the subscriber is transmitted short message
transmission starting messages. Said database may be
located in the subscriber database 11 shown in Figure
3. Said starting messages (Alert) start the transmission
of short messages from the short message service centers
SC1, SC2, SC3 to the subscribers MS. When the subscriber
MS has become reachable in the cellular communication
network, the subscriber location register 10 obtains a
notification thereof from the visitor location register
VLR, because in the visitor location register there has
been information, i.e. a set Messages-Waiting-Flag, on
the fact that the short message service center SC
contains short messages waiting to be transmitted to the
subscriber MS. The HLR function block 3 of the
subscriber location register thus requests information
from the database 11 on the conditions on-which said
subscriber should be transmitted short messages, i.e.
on what conditions the short message service center
storing short messages intended for said subscriber
should be transmitted said starting messages. It should
be noted that the teleoperator controls the conditions
included in said information maintained in the
subscriber location register 10; HLR in such a manner
that the subscriber location register 10; HLR transmits
short message transmission starting messages (SMS Alert)
- 219535~
to the short message service centers SCl, SC2, SC3
desired by the operator. After having made the request,
the HLR function block 3 receives said conditions and
decides on the basis thereof if a short message
transmission to said subscriber should be started. The
effect of different conditions on a short message
transmission will be described below. The HLR function
block then controls according to the conditions the
transmission means 1 transmitting short message
transmission starting messages, i.e. the starting
message transmission functions, to transmit the short
message starting messages of a certain subscriber, i.e.
Alert messages in the case of a GSM network, to those
short message service centers SC which have short
messages to be transmitted to the subscriber MS and to
which starting messages should be transmitted according
to said conditions. The starting message transmitting
means 1 thus transmit short message starting messages
in such a manner that the conditions which are
maintained in said database and which are in accordance
with the invention are observed. A short message service
center SCl, first according to the conditions, included
in the Messages-Waiting-Data-List of the subscriber
location register 10; HLR, associated with the IMSI, and
corresponding to the subscriber~s directory number, i.e.
MSISDN number, is transmitted one short message
transmission starting message, after which the starting
message transmitting means 1 wait for a predeterminable
period before transmitting a second short message
transmission starting message to the next short message
service center SC2. In the GSM system, for instance,
starting messages are transmitted in such a manner that
the transmitting means 1 requests the mobile
applications part MAP communication protocol 2 located
in the subscriber location register 10; HLR to transmit
2195355
a short message transmission starting message to the
short message service center SC, whereby the MAP carries
out the transmission of the starting message.
Figures 4 - 7 show a subscriber or subscriber
station Mobile MS, the home location register HLR of
said subscriber, and one or more short message service
centers SC, which store short messages intended for the
subscriber and which, according to the invention,
transmit said short messages to the subscriber in
accordance with predetermined conditions.
Figure 4 shows a signalling diagram of a
situation where the subscriber has become reachable, and
only part of the short message transmission starting
messages are transmitted. According to the invention,
the subscriber location register HLR transmits short
message transmission starting messages 404 to desired
short message service centers in accordance with the
conditions according to the invention. The transmission
of the starting messages is started when the subscriber
either transmits to her subscriber location register HLR
a notification of the fact that the subscriber can be
reached by the network again, i.e. a Note MS Present
message 401, performs a location updating, i.e.
transmits an Update Location message 402, or notifies
the subscriber location register that the subscriber has
memory capacity available by a Memory Capacity Available
message 403.
Figure 5 shows a signalling diagram of a
situation where a subscriber has become reachable, and
short message transmission starting messages are
transmitted to only certain short message service
centers. The transmission of the starting messages is
thus started by one of the above-mentioned messages
401 - 403 transmitted by the subscriber. The
transmission of the starting messages can thus be
5~56
prevented at the subscriber's request to all or part of
the short message service centers. It is also possible
that alerts destined for the addresses of only certain
service centers are allowed. In Figure 5, this situation
is illustrated by the fact that a starting message SMS
Alert 505 is not going to another service center even
if it goes to a desired service center.
Figure 6 shows a signalling diagram of a
situation where a subscriber has become reachable, and
short message transmission starting messages are
transmitted to only certain short message service
centers, depending on the subscriber's location. In the
situation shown in Figure 6, the transmission of
starting messages is prevented on the basis of the
location of the receiving subscriber. This is based on
the fact that the home location register HLR knows the
location of the receiving subscriber MS with an accuracy
of a mobile exchange, i.e. an MSC. Thus, a subscriber
MS, for instance, which is located outside a certain
area, for instance outside the service area of its own
home mobile exchange, is not transmitted short messages,
or short messages to be transmitted, located in a
certain service center, are not transmitted to a certain
.subscriber. This characteristic can be used for instance
when the subscribe-r is moving abroad and does not thus
want to receive short messages from her home country.
It is also possible to implement selective reception of
short messages in such a manner that when moving abroad,
the subscriber receives short messages only from the
country she is located in. Naturally, it is also
possible to implement other different and alternative
solutions in selective short message reception.
Figure 7 shows a signalling diagram of a
situation where a subscriber requests and controls the
transmission of short message transmission starting
'- 219~3~6 '~ -
messages. In this embodiment, the subscriber, i.e. the
mobile station or subscriber station, transmits to its
subscriber location register HLR a control instruction,
i.e. a Send SMS message 701, by which the subscriber
commands the subscriber location register to transmit
desired short message transmission starting messages 705
to those short message service centers SC which have
short messages to be transmitted to said subscriber MS.
In this embodiment, the subscriber location register
(home location register) HLR of the subscriber does not
thus start transmitting starting messages after having
received from the subscriber a Note MS Present message
401 or a location updating message Update Location or
a notification of the fact that the subscriber has
memory available, but starting messages are started to
be transmitted only at the subscriber's specific request
Send SMS.
The drawings and the description relating
thereto are only intended to illustrate the idea of the
invention. In their details, the method of the invention
for starting a short message transmission in a cellular
communication system, cellular communication system, and
cellular communication system subscriber location
register may vary within the scope of the claims.-Even
if the invention has been- described above mainly as
applied in the GSM system, it can also be used in a
-- radio-system of a different type.
