WO2002001894A1

WO2002001894A1 - Subscriber notification in a mobile telecommunications system

Info

Publication number: WO2002001894A1
Application number: PCT/EP2001/006289
Authority: WO
Inventors: Hannu VAINIOMÄKI; Reijo Pekkala
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2000-06-23
Filing date: 2001-06-01
Publication date: 2002-01-03
Also published as: AU2001283833A1; GB2368232A; GB2368232B; GB0015280D0

Abstract

A method of notifying a mobile subscriber of an event or of information relating to an event occurring in a mobile telecommunications network. The method comprises, upon the occurrence of said event in the mobile telecommunications network, identifying the event to a common USSD function (9). From the common USSD function (9), a database (10) associated with the common USSD function (9) is accessed to identify a USSD message associated in the database (9) with said event. The USSD message is sent to the mobile subscriber's station (5) and the USSD message displayed on a display (6) of the station (5).

Description

SUBSCRIBER NOTIFICATION IN A MOBILE TELECOMMUNICATIONS SYSTEM

Field of the Invention

The present invention relates to subscriber notification in a mobile telecommunications network and more particularly to a method and system for sending subscriber notifications from mobile telecommunications networks to user stations.

Background to the invention

National telecommunication networks are becoming increasingly harmonised by the creation of international standards. For example, the GSM mobile standard has been widely introduced in Europe and elsewhere, and it is expected that the replacement for GSM, known as UMTS, will extend the current harmonisation still further. Whilst this brings many benefits, including the possibility for users of mobile stations to roam across national boundaries, cheaper infrastructure and stations, etc, it can bring problems due to the need to satisfy the requirements (e.g. legal) of many different nations. For example, different nations (that is to say national governments, authorities, or operators) may demand the ability to send specific messages from their networks to subscriber stations.

In Japan, a regulatory requirement exists for the handling of Calling Line Identification Presentation (CLIP) and emergency calls. In particular, if the identity of a party (or line) calling a mobile subscriber cannot be identified (e.g. because the caller has withheld his identity), then details of the reason for the unavailability of the identity must be sent to the station and displayed to the subscriber. Similarly, in the event that a mobile subscriber makes an emergency call and subsequently initiates call clearing towards the network, the subscriber should be notified that the call has been placed on hold for a predefined maximum period of time (in order to allow the emergency services to call the subscriber back). These requirements will apply to both GSM and UMTS networks. In order to satisfy the demand for the sending of national and operator specific notifications from mobile networks to mobile stations, attempts have been made to redefine the relevant standards. Typically, this requires the making of appropriate modifications to the Radio Access Network Application Part (RANAP) in UMTS and to the Direct Transfer Application Part (DTAP) in GSM. It will be appreciated that it is difficult (or impossible) to write the RANAP/DTAP standard in such a way as to accommodate the disparate demands of many different countries and authorities. Moreover, once the RANAP/DTAP standard has been fixed, it is difficult to further modify the standard to incorporate future demands, particularly as this would require modifications not only within networks but also to mobile stations.

Summary of the Present Invention.

The inventors of the present invention have recognised that the problem identified above may be overcome by utilising Unstructured Supplementary Services Data (USSD) messages to carry information to mobile stations. USSD is currently specified in UMTS and GSM as a mechanism for exchanging information between mobile stations and mobile networks. However, in order to make such a mechanism practical to implement, it has been recognised that within a network node from which USSD messages may be sent a common USSD function should be provided. This common USSD function handles USSD specific processing for all events which require the sending of USSD messages.

According to a first aspect of the present invention there is provided a method of notifying a mobile subscriber of. an event or of information relating to an event occurring in a mobile telecommunications network, the method comprising:

(a) upon the occurrence of said event in the mobile telecommunications network, identifying the event to a common USSD function;

(b) from the common USSD function, accessing a database associated with the common USSD function to identify a USSD message associated in the database with said event;

(c) causing the USSD message to be sent to the mobile subscriber's station; and (d) receiving the USSD message at said station and displaying the message on a display of the station.

Embodiments of the present invention avoid the need to modify standards such as RANAP/DTAP, as these standards already provide for the transmission of USSD messages to mobile stations. Furthermore, as a common USSD function is available for all events which trigger the sending of USSD messages, only relatively minor changes to existing software is required for each event/USSD message pair. Once such modifications have been made, the database associated with the USSD function need only be updated to include the identity of the event and the associated USSD message. It is a relatively simple operation to amend entries in, and delete entries from, the database.

In certain embodiments of the invention, the network is a UMTS network and steps (a) to (c) are carried out in a MSC/VLR server. Step (c) involves passing the USSD message from the USSD function to a RANAP entity, where the USSD message is incorporated into the payload of a RANAP message. The invention may also be employed in GSM networks.

Steps (a) to (c) may be carried out in network nodes other than the MSC/VLR server. For example, they may be carried out in a HLR or CAMEL server. Step (c) may comprise passing the USSD message to a MAP entity, where the message is incorporated into the payload of a MAP message for transmission to the serving MSC/VLR. At the MSC/VLR server, a translation may be carried out to convert the MAP message into a RANAP/DTAP message.

In step (a), the occurrence of an event may be detected by a Connection Management (CM) process, which notifies the USSD function of the event.

It will be appreciated that the present invention may be employed to send notifications to mobile stations relating to various events. For example, the event may be a request to set up a call to a mobile station, where the calling line identity of the calling party is not available. The USSD message sent to the mobile station may identify the reason for the unavailability of the identity. Another example of an appropriate event may be the attempt to terminate an emergency call by a mobile station, following which the network places the call on hold so that, if necessary, the call can be re-established by the called emergency service. The USSD message sent to the mobile station advises the station that the call is now on hold.

According to a second aspect of the present invention there is provided apparatus for notifying a mobile subscriber of an event or of information relating to an event occurring in a mobile telecommunications network, the apparatus comprising: first processing means arranged to detect the occurrence of said event in the mobile telecommunications network; second processing means implementing a common USSD function, the first processing means being arranged to identify the event to said second processing means following detection of the event; a memory storing a database of events and associated USSD messages, the second processing means being arranged to access the database to identify a USSD message associated in the database with the identified event; and third processing means for causing the USSD message to be sent to the mobile subscriber's station for display on a display of that station.

Brief Description of the Drawings

Figure 1 illustrates schematically a UMTS mobile telecommunications network; Figure 2 illustrates certain functional entities of the network of Figure 1; and Figure 3 is a flow diagram illustrating a method of sending network notifications from the a network node of the network of Figure 1 to a mobile station.

Detailed Description of Certain Embodiments

There is illustrated in Figure 1 a UMTS mobile telecommunications network. The network includes a UMTS Terrestrial Radio Access Network (UTRAN) part 1 and a circuit switched core network part 2 (the network also includes a GPRS core network part but this is omitted from Figure 1). The core network 2 consists of a number of Mobile Switching Centres (MSCs) co-located with respective Visitor Location Registers (VLRs). Only one MSC/VLR 3 is illustrated in Figure 1. Also shown in the core network 2 is a Home Location Register (HLR) 4. In use, a mobile station (MS) 5 belonging to a subscriber of the UMTS network is registered with the MSC/VLR 3 - the MSC/VLR being referred to as the serving MSC/VLR for the MS 5. The UTRAN 1 is responsible for allocating and controlling radio resources between the network and the MS 5 according to requests received from the core networks.

The MSC/VLR 3 is responsible for setting-up and tearing down connections between the MS 5 and other called or calling parties. This functionality is handled in the MSC 3 by a Connection Management (CM) process. There are a number of events occurring at or recognised by the MSC/VLR 3 which should be notified to the subscriber. Reference has already been made above to the requirement in Japan to notify a called mobile subscriber of the detailed reason for not presenting a calling line identity, and to notify a subscriber when the network places on hold an emergency call which the subscriber has attempted to terminate. These and other events can be detected from within the CM process.

The existing CM process 7 is modified to include a common USSD functional entity (or handler). This architecture is illustrated in Figure 2 where the "core" CM process is indicated by reference numeral 8 and the USSD entity by numeral 9. The USSD entity 9 is responsible for generating appropriate USSD messages (typically, the start of a USSD message is identified by a "*" whilst the end of a USSD message is identified by a "#"), for setting -up and releasing transactions between the MSC 3 and the MS 5, and for initiating the sending of generated USSD messages using set-up transactions. This functionality is described in more detail in the ETSI standards 3GPP TS 22.090, 23.090, and 24.90 (USSD is described for GSM in TS 02.90 and 03.90).

The USSD entity is provided with a database 10 in which are recorded event identities and respective USSD messages. The occurrence of certain events within the CM process 8 is arranged to generate a call to the USSD entity 9. The call includes the identity of the triggering event. Following a call, the USSD entity 9 accesses the database 10 to identify the USSD message associated with the received event identity, and the identified USSD message is retrieved from the database 10. The USSD message is passed to the RANAP entity 11 of the MSC 3. The USSD message is incorporated into the payload of a RANAP message.

The generated RANAP message is then sent from the MSC/VLR 3 to the UTRAN 1 from where it is transmitted over the air interface to the MS 5. At the MS 5, the USSD message is decapsulated from the RANAP message at the RANAP entity 12 of the MS 5. The destination application part 13 for the USSD message is identified from the message header, and the USSD message forwarded accordingly. The application part 13 responds to receipt of the message by displaying the contents of the message on the display 6 of the MS.

The method described above is further illustrated by the flow diagram of Figure 3. It will be apparent that in order to change an existing USSD message, it is only necessary to change the corresponding entry in the database 10. Similarly, it is relatively straightforward to add a new event identity and USSD message to the database 10 in the event that the CM process is modified to detect a new event and to call the USSD entity upon occurrence of that event.

It will be appreciated by the person of skill in the art that various modifications may be made to the above described embodiment without departing from the scope of the present invention. For example, the USSD entity may be provided at a HLR or other network node, such that detection of an event at that node causes a USSD message to be sent (via the serving MSC) to a MS. Instead of RANAP, the MAP protocol may be used to carry USSD messages through the network to the MSC, where they are transferred to RANAP messages for transmission through the UTRAN and over the radio interface.

Claims

1. A method of notifying a mobile subscriber of an event or of information relating to an event occurring in a mobile telecommunications network, the method comprising:

(c) causing the USSD message to be sent to the mobile subscriber's station; and

(d) receiving the USSD message at said station and displaying the message on a display of the station.

2. A method according to claim 1, wherein the network is a UMTS network and steps (a) to (c) are carried out in a serving MSC/VLR.

3. A method according to claim 2, wherein step (c) involves passing the USSD message from the USSD function to a RANAP entity, where the USSD message is incorporated into the payload of a RANAP message.

4. A method according to claim 3, wherein the network is a GSM network.

5. A method according to claim 1, wherein steps (a) to (c) are carried out in a HLR or CAMEL server.

6. A method according to claim 1, wherein step (c) comprises passing the USSD message to a MAP entity, where the message is incorporated into the payload of a MAP message for transmission to a serving MSC/VLR.

7. A method according to claim 1, wherein in step (a), the occurrence of an event is detected by a Connection Management (CM) process, which notifies the USSD function of the event.

8. A method according to claim 1, wherein said event is a request to set up a call to a mobile station, where the calling line identity of the calling party is not available, and the USSD message sent to the mobile station identifies the reason for the unavailability of the identity.

9. A method according to claim 1, wherein the event is an attempt to terminate an emergency call by a mobile station, following which the network places the call on hold so that, if necessary, the call can be re-established by the called emergency service, the USSD message sent to the mobile station advising the station that the call is now on hold.

10. Apparatus for notifying a mobile subscriber of an event or of information relating to an event occurring in a mobile telecommunications network, the apparatus comprising: first processing means arranged to detect the occurrence of said event in the mobile telecommunications network; second processing means implementing a common USSD function, the first processing means being arranged to identify the event to said second processing means following detection of the event; a memory storing a database of events and associated USSD messages, the second processing means being arranged to access the database to identify a USSD message associated in the database with the identified event; and third processing means for causing the USSD message to be sent to the mobile subscriber's station for display on a display of that station.