Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02509932 2000-09-O1
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CHARGING FOR PREPATD SUBSCRIBERS IN A TELECOMMUNICATIONS
SYSTEM
Background of the invention
The present invention relates to a method and an equipment for
enabling versatile charging in telecommunications systems and especially
more versatile charging for prepaid subscribers. A prepaid subscriber refers
to
a subscriber using prepaid subscription, i.e. a subscriber who has paid in ad-
vance.
In mobile telecommunications systems, such as the pan-European
digital mobile communications system GSM (Global System for Mobile Com-
munications), call prices depend usually on the time when the call is made. To
be able to offer more versatile charging possibilities some operators offer
pre-
paid service for subscribers. A prepaid service is a service where a
subscriber
pays in advance his calls by buying vouchers. The prepaid service logic and
prepaid service data are stored in the system. A prepaid SIM (Subscriber
identity Module) card comprises an MSISDN number which is associated with
the prepaid service data, including the subscriber's credit, in the system. A
prepaid service allows payment of a telephone bill in advance or setting an
upper limit for the telephone bills. As another benefit, the prepaid service
en-
able roaming subscribers to pay their local calls at local tariffs, whereas
the
2o use of the SIM card of their home service provider results in paying
interna-
tional tariffs to their home network and back.
Usually a prepaid subscription is activated and money added to
subscriber's prepaid account by means of vouchers. Some of the service pro-
viders sell different types of vouchers, which differ from each other e.g. in
the
25 number of call units and the time the call time bought is valid. However,
the
calls are charged in the same way regardless of what kind of a voucher is
used.
The above described possibilities for charging calls are insufficient,
since the needs of mobile subscribers and their use of their mobile stations
are
3o becoming more and more differentiated. There are users making lot of calls
during office hours whereas some other users call seldom and during eve-
nings, for example. The charging of calls has to be diversified
correspondingly.
Disclosure of the invention
The object of the invention is to provide versatile charging possibili-
35 ties that are easy to maintain and define by the operator. The object of
the in-
CA 02509932 2000-09-O1
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vention is achieved with methods, a system, a network element and databases
which are characterized in what is disclosed in the independent claims. The
preferred embodiments of the invention are set forth in the dependent claims.
The invention is based on defining at least two different kinds of tariff
models
and associating a subscriber's information directly or indirectly with a
tariff model
which is used when the subscriber makes a call. With tariff models the
charging of
subscribers is easily diversified.
The advantages of the invention are that the service provider can customize
the charging very easily and for example direct some users to call during
times when
the network is not very loaded.
In one embodiment of the invention, where the prepaid service is used, each
voucher type has a tariff model. The further advantage of this embodiment is
that a
subscriber can change his tariff model by changing the voucher type he is
using.
In another embodiment of the invention, where the prepaid service is used,
voucher types allowed for subscribers are defined. The further advantage of
this
embodiment is that the operator can restrict the subscriber's freedom to
choose a
tariff model to be used.
According to a broad aspect of present invention there is provided a network
element (SCP) controlling charging of a subscriber in a telecommunications
system.
ZO The network element comprises means for obtaining subscriber information
maintained in the telecommunicationsystem. The network element (SCP)
comprises means for finding out which of tariff models defined in the
telecommunications system is to be used with this subscriber from the
subscriber
information indicating the subscriber's tariff model. Each tariff model
contains a tariff
scheme defining how to charge a call, and for using the tariff scheme of the
indicated
tariff model when charging the subscriber.
Brief description of the figures
The invention will be described in further detail in the following by means of
preferred embodiments with reference to the accompanying drawings, in which
CA 02509932 2000-09-O1
2a
Figure I is a block diagram showing some relevant network elements in a first
preferred embodiment of the invention;
Figure 2 is a block diagram showing some relevant elements of the SMP in
the first preferred embodiment of the invention;
Figure 3 is a flow chart illustrating charging in the first preferred
embodiment;
and
Figure 4 is a flow chart illustrating depositing in the first preferred
embodiment.
Detailed description of the invention
Figure 1 is a block diagram of a telecommunications system S equipped with
an arrangement according to a first preferred embodiment of the invention. The
telecommunications network is assumed to be a public land
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mobile network Pl.MN, without, however, limiting the invention to that kind of
particular network. The invention can be used in any telecommunications
systems where subscribers have subscription information stored in the system
and the subscription information is used when calls are charged.
The embodiment illustrated in Figure 1 makes use of Intelligent
Network technology. An intelligent network IN is able to provide a subscriber
of
a telecommunications network, such as a wired network or a mobile telephone
network, with a plurality of services. An example of such an intelligent
network
is described in recommendations of the ITU-T Q-1200 series, of which Q-1210
~o to Q-1219 define a set of features known as CS-1 (Capability Set 1), and
cor-
respondingly, Q-1220 to Q-1229 define a set of features CS-2. The invention
and its background will be described by the terminology of recommendation
ETS 300 374-1 CoreINAP, but the invention can also be employed in intelli-
gent networks implemented according to other intelligent network standards.
~s Figure 1 shows some elements of an intelligent network which are
relevant to the understanding of the invention, such as what are known as in-
telligent peripherals IP. Usually an IP is associated with a specialized
resource
function SRF which is an interface for network mechanisms associated with
interaction with a subscriber. Thus an IP may comprise e.g. more advanced
2o speech handling functions than do exchanges in general. The IVR application
is usually located in the IP. The IVR application, also called the Prepaid
serv-
ice IVR application, is an interactive voice response application that allows
the
subscriber to make a deposit (add money, recharge} into his Prepaid S1M ac-
count by entering the identification number of a prepaid voucher. The iP is
25 connected to an SSP using for example ISUP (ISDN User Part) signalling and
one or more voice transports.
The SSP (Service Switching Point) is a network element performing
service switching function (SSF). The SSP may be a mobile service switching
centre MSC, which includes the SSF. The SSF is an interface between a con-
ao ventional call control function CCF and the service control function SCF of
an
intelligent network. The network element performing the SCF is called a serv-
ice control point SCP. An intelligent network service is produced by the
service
switching point SSP inquiring instructions from the service control point SCP
by ri~eans of messages to be transmitted across the SSPfSCP interface upon
35 the encounter of detection points associated with the service. In
association
with an intelligent network service, a service logic program is started at the
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service control point SCP, the operation of the program determining the mes-
sages transmitted by the SCP to the SSP at each stage of a call. During one
call there may be several service logic programs started and ended. The
service logic program handling a prepaid call runs during the whole call,
since
it controls credit updating. Usually the SCP controls the charging and adjusts
the charging on the basis of information it gets from the SSP. The credit up-
dating according to the invention is discussed in greater detail in Figure 3.
However, usually the SCP is not used in the service logic of the
Prepaid SIM IVR recharge application, i.e. calls to the IVR are routed by the
CCF directly to the IVR on the basis of the service number which the sub-
scriber has dialled in order to recharge (deposit).
In the example illustrated in Figure 1, prepaid subscriber informa-
tion, information about vouchers, prepaid profile definitions and tariff
models -
are in a database located in a service management point SMP as is described
~5 in greater detail in Figure 2. Alternatively, they may be (orated in
different da-
tabases and/or in some other network element, like a home location register
HLR (not shown in Figure 1). The database may also be a decentralized data-
base. The IVR interfaces the SMP database through a service management
interface SMI. The SMP and the IP may be connected e.g. through a local
zo area network (LAN) using TCPIlP (Transmission Control Protocol/lnternet
Protocol). The connection between the 1P and the SMP, illustrated by a
dashed line, represents only management connection without any signalling
connection.
The service management access point SMAP provides some se-
25 lected users, such as service providers and network operators, with access
to
the service data of the service management point SMP through a public tele-
phone network, such as the PSTN or the 1SDN, a cellular radio network (such
as the GSM) or a public data network (X.25, the Internet) and an open inter-
face. The SMAP interacts directly with the SMP. Furthermore, the SMAP can
3o provide access to a nefinrork element of another telecommunications
network.
The operator can define and redefine tariff models via the SMAP. The SMAP
is described in greater detail in PCT patent application W098I41038 which is
incorporated herein by reference.
Network operators and service providers are nowadays separated.
35 A service provider buys the required bearer services from a network
operator.
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rJ
A network operator may also be a service provider. An operator may also have
multiple service providers.
Figure 2 is a block diagram showing the relevant parts of the SMP
in the first preferred embodiment of the invention. In the first preferred em-
bodiment of the invention, each voucher type VT is associated with one tariff
model TM-ID and subscriber information Si comprises information about the
voucher type currently in use, VTu. With this information, the tariff to be
used
is easily found when needed. Besides the voucher type VT and the tariff mode!
identifier TM-ID, voucher information V! may comprise also other information
like a CV indicating how many months the credit is valid for recharge and a
voucher price VP as is illustrated in the example in Figure 2.
The tariff model TM comprises a tariff model identifier ID, weekday
definitions WD, time definitions T, prices per minute P and in the example il-
lustrated in Figure 2, also prefixes Pr. Wtth prefixes it is possible to have
dif-
~5 ferent call prices within one tariff model to different telephone numbers.
The
price without a prefix is used when the dialled number does not match any
prefix defined in caller's tariff model. Each tariff model comprises
preferably a
unique tariff scheme. For example tariff model 7 is for persons normally
calling
during office hours whereas tariff model 2 is for persons calling in the
evenings
2o and weekends. Jn the tariff model 1 the possibility to differentiate call
prices by
a prefix is used: certain calls tolin Finland are cheaper than other calls
during
office hours. The tariff models illustrated in Figure 2 are purely
illustrative. The
service provider can define various tariff models, change definitions and add
new models. The tariff model may have different prices for data calls, multime-
25 dia calls or messages, short messages, or prices for calls where also the
called person is charged, for example. The simplest tariff model is a model
where one price is used all the time.
Subscriber information SI comprises in the first preferred embodi
ment subscribers' phone numbers MSISDNs, each associated with a profile
3o identifier P-ID and a voucher type currently in use VTu. instead of or in
addi
tion to MSISDNs, subscribers identifiers IMSIs may also be used in other em-
bodiments. The profile identifier identifies the profile whose information is
to be
used with this subscriber.
Predefined profile information PP comprises at least a profile identi-
35 fier P-ID and voucher types allowed to that profile, VTa. With the allowed
voucher types VTa, the service provider can restrict the vouchers the sub-
CA 02509932 2000-09-O1
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scriber is allowed to use. One subscriber may use all kind of vouchers,
whereas another subscriber may be restricted to only one voucher type. These
allowed voucher types are used during recharges as illustrated in greater de-
tail in Figure 4. The predefined profile may also comprise values for
different
kind of prepaid service attributes, for example an indication how to calculate
a
new credit when a subscriber deposits.
In the second preferred embodiment of the invention, all subscrib-
ers are required to use only one kind of tariffing and only one kind of
voucher.
Thus the allowed voucher types VTa comprise only one voucher type. The
tariff model identifier TM-ID is either in the voucher information (as in
Figure 2)
or in the prepaid profile definitions. In the second embodiment there is no
need
to store information indicating the currently used profile VTu in the
subscriber
information SI since it is the same as the only allowed voucher type VT'a in
the
prepaid profile information.
The third preferred embodiment of the invention differs from the first
preferred embodiment in that no prepaid profiles are used. Thus all subscrib-
ers can use ail kinds of vouchers. Naturally, in the third preferred
embodiment
of the invention no prepaid profile information is maintained.
In the fourth preferred embodiment of the invention, all subscribers
2o are required to use only one kind of tariffing but some of them are allowed
to
use different kind of vouchers. This embodiment differs from the first embodi
ment of the invention in that the tariff mode! identifier is defined either in
the
prepaid profile information or in the subscriber information, not in the
voucher
information. In this embodiment the difference between vouchers could be the
25 price of the vouchers. Also subscribers having a different prepaid profile
can
have different kinds of charging, even if they use the same voucher type.
In the fifth preferred embodiment, no prepaid profiles are used and
the subscriber information Sl also comprises information about allowed
voucher types VTa.
30 In another embodiment of the invention one tariff model is defined
to be a default model which is used when no other mode( is defined for that
subscriber or voucher. The advantage of this embodiment is that there is no
need to add a tariff model to old subscriber information or voucher
information.
These embodiments are only illustrative and different kinds of fur-
35 they embodiments can be built by taking a single feature or features of
them
and combining them.
CA 02509932 2000-09-O1
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Figure 3 is a flow chart illustrating an example of how the charging
base is determined according to the first preferred embodiment of the inven-
tion. In this example it will be assumed that the IN and, more precisely, the
SCP is responsible for keeping track of the available credit of the prepaid
sub-
s scriber, but this is not necessary to the invention. It is also possible
that it is
the MSC (SSP) that keeps track of the available credit of the prepaid sub-
scriber. Another assumption, made here, is that the SCP stores the available
credit to an IN database called Service Data Point (SDP, not shown separately
in Figure 1) which is a database for the SCP. It is also assumed that_the call
made here is not an emergency calf.
Referring to Figure 3, a prepaid subscriber has dialled numbers in
dicating that he wants to make a call which is charged from him. The SSP no
tices that the caller is a prepaid caller and sends a prepaid service request
to
the SCP. In step 301, the SCP deduces from the service request the caller's
identification, which in the first preferred embodiment of the invention is
the
MSISDN. In step 302, it is checked if the subscriber's available credit is
zero,
i.e. has he used all his money. Since the available credit is stored in the
SDP,
it did not have to be transferred to the SCP. If the available credit is zero,
call
connection is terminated in step 303. In some other embodiments some other
20 credit limit than zero may be used.
If a subscriber still has some money on his account, the SCP ob-
tains in step 304 the voucher type currently in use, VTu, from the subscriber
information SI located in the SMP on the basis of the MSISDN. The SCP then
obtains in step 305 the tariff model identifier TM-ID from voucher information
25 VI located in the SMP on the basis of VTu. In step 306 the tariff scheme in
the
tariff model is obtained from the tariff model information TM located in the
SMP
on the basis of the TM-ID.
The SCP then notifies in step 307 the switching point (SSP) by
sending an instruction message of the events which affect call price formation
3o and are to be reported by the switching point (SSP) to the control point
(SCP)
in a report message.
When the call is connected, the SCP reduces in step 308 the value
of available credit during the calf according to the tariff scheme in the
tariff
model. Naturally, the SCP adapts, when needed, reduction of the available
3s credit according to the messages received from the SSP.
CA 02509932 2000-09-O1
in other embodiments of the invention described in Figure 2, the
tariff model to be used may be searched differently from what is described
above in Figure 3 depending where and what information is required to find
out the tariff model.
In some other embodiments of the invention the SCP may send the
MSISDN to the SMP, and SMP carries out the data search described in steps
304-306 and sends as a response to the SCP the tariff scheme in the tariff
model.
Figure 4 is a flow chart illustrating the depositing in the first pre-
ferred embodiment of the invention. In this example it is assumed that the IVR
is taking care of the depositing and the voucher is assumed to be valid. In
the
example illustrated in Figure 4, it is also assumed that the voucher
identifica-
tion numbers are used to identify the type of the voucher, so that e.g. when
two types of vouchers are used, the identification numbers on list 1 are of
type
~5 1 and the missing numbers are of type 2. It is, however, irrelevant to the
in-
vention how the type of the voucher is determined.
Referring to Figure 4, a subscriber has bought a voucher from a
shop, called to the IVR and selected to deposit the voucher. The subscriber is
assumed to be a prepaid subscriber, otherwise he cannot deposit. It is also
2o assumed that the IVR checks at the beginning of the cal! if the caller is a
pre-
paid subscriber, and if not, then the call is disconnected or connected to cus-
tourer service.
Figure 4 begins in step 401, where the IVR deduces the caller's
identification, which is in the first preferred embodiment the MSISDN. On the
25 basis of the MSISDN the IVR obtains, in step 402, the caller's prepaid
profile
identifier P-ID from the subscriber information SI located in the SMP. On the
basis of profile identifier P-ID, the IVR obtains, in step 403, the allowed
voucher types VTas from the predefined profile information PP located in the
SMP. In embodiments where the profile information also comprises other in-
3o formation related to depositing, this information is also obtained in step
403. In
step 404, the IVR prompts the subscriber for voucher identification ID. The
voucher identification number ID is received in step 405. The validity of the
voucher is checked (not shown in Figure 4) and after that, in step 406, the
IVR
determines the type T of voucher e.g. by using the identification number and
3s going through lists) in order to find out the types. After the voucher type
T is
determined, the 1VR checks, in step 407, if the voucher type is an allowed
one.
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In other words, the IVR checks whether the type T belongs to the allowed
voucher types VTas. If so, the 1VR continues depositing in step 408, the de-
tailed steps of which are not shown in Figure 4. The depositing is carried out
according to prior art, but in the future the depositing may also be carried
out
s by new depositing methods not known today. If the deposit was carried out
(step 409), in step 410 the IVR sets in the subscriber information the voucher
type currently in use VTu to voucher type T and then ends the depositing in
step 411, the detailed steps of which are not shown in Figure 4.
If the deposit is not carried out (step 409), e.g. because the caller
changes his mind due to losing current credit, then the IVR gives an audio
message "goodbye" in step 412 and no subscriber-related information is
changed. The call is disconnected.
If the voucher which the caller is trying to deposit is not one of the
allowed voucher types {step 407), then the IVR quits without doing any updat
~5 ing and gives in step 412 an audio message telling that the voucher type
the
caller is trying to deposit, is not an allowed one. The IVR also gives in the
audio message the allowed voucher types VTas in step 412.
in some other embodiments of the invention the IVR may send the
MSISDN to the SMP, and the SMP performs the data search described in
2o steps 402 and 403 and sends as a response to the SCP the allowed voucher
types VTas.
The steps have not been set out in absolute time sequence in Fig-
ures 3 and 4. Some of the above steps may take place simultaneously or in a
different order, for example steps 409-403 and 404-406. Some steps may also
25 be skipped, like the step 402 in embodiments where subscriber information
comprises allowed voucher types VTas. Other steps not shown in Figures 3
and 4 may also occur between the steps stated above. instead of some steps
shown in Figures 3 and 4, some other step having the same result, may be
performed. For example in some embodiments, step 304 may be replaced by
3o steps where the voucher number currently in use is used for determining the
voucher type.
The present invention can be implemented in existing network ele-
ments. They all have processors and a memory with which the inventive func-
tionality described below can be implemented. The functions described above
s5 may be located in one network element or some of them may be in one ele-
CA 02509932 2000-09-O1
ment and the others in other elements regardless of how they are located in
the examples which illustrate the invention.
Although the invention is described above assuming that the sub
scriber is a prepaid subscriber and the system is a prepaid system, the inven
5 tion may be implemented also for conventional subscribers who are charged
afterwards. When the implementation involves conventional subscribers, the
tariff model identifier is preferably added to the subscriber information
stored in
the subscriber information database, such as a home location register in the
GSM system. It is also possible to use profile definitions with conventional
1o subscribers. This invention is not limited to mobile systems but it may be
im-
plemented in any kind of telecommunications system, e.g. fixed systems,
storing subscriber information, like the PSTN (Public Switch Telephone Net-
work) or the so called third generation system UMTS (Universal Mobile Tele-
communications System) and lMT-2000 (International Mobile Telecommunica-
tion 2000). It is also possible to provide prepaid service to fixed
subscribers in
a similar way as is illustrated here with the above figures.
The accompanying drawings and the description pertaining to them
are only intended to illustrate the present invention. Different variations
and
modifications to the invention will be apparent to those skilled in the art,
with-
out departing from the scope and spirit of the invention defined in the ap-
pended claims.
