GB2307828A - Providing Packet Data to a Mobile Communications System - Google Patents

Abstract

An arrangement for routing packet data from a packet data network 19 to mobile network subscriber terminals 10 served by a mobile switching centre 14 includes an interface 18 between the mobile network and the packet network. A server 20 is disposed between the interface and the mobile terminals Messaging is provided between the mobile terminals and the server and between the server and the interface whereby to control delivery of data packets via the server to the mobile terminals.

Description

MOBILE COMMUNICATIONS SYSTEM This invention relates to mobile communications systems and in particular to the provision of packet data services in a mobile system.

Mobile telephone networks were originally developed to provide voice services to customers. However, customers are now demanding access to many of the services, including packet data services, that are now provided on the conventional wired network. It is of course difficult to determine the precise location of a mobile user who is free to roam throughout the mobile service area. The problem of routing and delivery of packet data in a mobile network is exacerbated by the lack of a suitable management infrastructure for handling data traffic. This is a particular problem for broadcast and multicast data services.

The object of the invention is to minimise or to overcome this disadvantage.

According to one aspect of the invention there is provided an arrangement for routing packet data from a packet data network to mobile network subscriber terminals served by a mobile switching centre, the arrangement including an interface means between the mobile network and the packet network, a server disposed between the interface and the mobile terminals, first means for providing messaging between said mobile terminals and the server, and second means for providing messaging between the server and the interface whereby to control delivery of data packets via the server to the mobile terminals.

According to another aspect of the invention there is proviided a method of routing packet data messages from a packet data network to mobile network subscriber terminals served by a mobile switching centre, there being an interface provided between the mobile network and the packet network and a server disposed between the interface and the mobile terminals, the method including providing a first messaging stage between said mobile terminals and the server, and providing a second messaging stage between the server and the interface whereby to control delivery of data packets via the server to all or to a selected group of the mobile terminals.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic design of a mobile telecommunications network provided with a packet data service; Figure 2 illustrates a procedure for packet data service registration and deregistration in the network of Figure 1; Figures 3 and 4 illustrate mobile originated singlecast messaging in the system of figure 1; Figures 5 and 6 illustrate mobile terminated messaging in the system of figure 1; and Figure 7 illustrates multicast/broadcast messaging in the system of figure 1.

Referring to Figure 1, the mobile system include an array of cells 11 each served by a respective base station 12 providing communication with subscriber terminals 10 currently located in that cell. A number of base stations are controlled by a base station controller 13 which in turn is coupled to a mobile switching centre (MSC) 14. The MSC incorporates a database or visitors location register (VLR) 15 containing information on the cellular location of mobile terminals 10 currently in the service area of that MSC. Information on all system mobiles 10 is stored in a central database or home location register (HLR) 16 which may be accessed by the MSC to update the VLR whenever a mobile terminal enters the service area of the MSC.The MSC facilitates coupling between the mobile system and a fixed network, e.g. a PSTN 17 whereby calls may be established between mobile network and fixed network sub scribers and between mobile subscribers served by different MSCs.

The mobile network is provided with an interface or packet data interworking function (PDIWF) 18 whereby packet data traffic may be carried between the mobile network and a packet data network 19. Access of mobile terminals to packet data services is effected via a server provider access point 20 (SPAP) conveniently forming part of the MSC. Data traffic between a mobile terminal (MS) and the packet data network is controlled via a first messaging protocol between the mobile terminal 10 and the SPAP 20 and via a second messaging protocol between the SPAP 20 and the PDIWF 18. These messages comprise either service provider messages relating to traffic to mobile subscribers or service subscriber messages relating to traffic from mobile subscribers.

The messages are associated with two types of call; broadcast and multicast. A broadcast call is a point to multipoint message sent to all service subscribers within an area defined by the service provider. A multicast message is a point to multipoint message sent to an identified subset of the service subscriber within the area defined by the service provider. The system may also incorporate single cast messaging, i.e. a point to point message sent to a single mobile subscriber.A typical list of message types and directions is illustrated in Table 1 below: Table 1

Message Name Message Direction Message Types Service Provider SPAP- > PDIWF Singlecast Acknowledged Singlecast Unacknowledged Multicast Broadcast Acknowledgement Service Subscriber MS- > SPAP Registration Message Deregistration Singlecast Acknowledged Singlecast Unacknowledged Acknowledgement Group Update SPAP- > PDIWF Create Group Message Modify Group PDIWF PDIWF- > SPAP Acknowledgement Acknowledgement Each message incorporates a header which can contain identifiers indicative of the provider, the subscriber, the message type he uses and the subscriber group. The requirements for identifiers are detailed in Table 2 below which relates to service provider messages and in Table 3 below which relates to service subscriber messages: Table 2

Singlecast Singlecast Multicast Broadcast Acknowledge Ack Unack.

Provider M M M M M Identifier Message M M M M M Type Identifier Subscriber M M NA NA M Identifier User O O M M NA Identifier Group NA NA M NA NA Identifier Table 3

Registration Deregistration Singlecast Singlecast Acknowledg Ack. Unack.

Provider M M M M M Identifier Message M M M M M Type Identifier Subscriber M M M M M Identifier Area NA NA NA NA NA Identifier Group NA NA NA NA NA Identifier In Tables 1 and 2, the reference M signifies that the identifier is mandatory and NA that an identifier is not Applicable The message area identification relates to a selection from a set of areas previously defined by the service provider and the mobile network operator.

The group identifier relates to a group related from the service provider's set of groups. Membership of these groups may be stored in a group register provided in the service providers 'anchor' PDIWF. Group membership may be updated by the service provider via group update messages. This latter procedure will be described below.

Messaging sequences for effecting subscriber registration and deregistration are illustrated in figure 2. An initial part of the registration includes a message from the PDIWF to the mobile system home location register (HLR) whereby the HLR is updated with the service entitlement of the subscriber. When this message is acknowledged, registration of the subscriber with the PDIWF can then take place. The process is completed by an acknowledgement from the PDIWF to the mobile confirming successful registration thus allowing a service connection to be made.

Deregistration of the mobile is a reversal of the process. The messaging protocol of figure 2 indicates that the registration to a packet radio service and registration to the application provided via that service comprise separate procedures.

As discussed above, data messaging in the system may comprise singlecast, which may be acknowledged or unacknowledged, or multicast or broadcast. Protocols for singlecast messaging are illustrated in figures 3 to 6. Figures 3 and 4 relate respectively to mobile terminated acknowledged and unacknowledged messaging, and figures 5 and 6 relate respectively to mobile originated acknowledged and unacknowledged messaging.

Figure 7 illustrates the procedure for multicast and broadcast messaging.

There is little procedural difference between these two classes of messaging, although if a cell area spans two or more MSC service areas, then the SERVICE PROVIDER MESSAGE is relayed to each associated PDIWF. This requires SPI messages to be transferred between the respective PDIWF, and for each PDIWF to have a capability of identifying the cell areas within its associated MSC service area. It will be appreciated that there is no acknowledgement of a multicast or broadcast message.

Each base station receives the message and is then responsible for broadcasting across the corresponding cell.

Claims (6)

1. A method of routing packet data messages from a packet data network to mobile network subscriber terminals served by a mobile switching centre, there being an interface provided between the mobile network and the packet network and a server disposed between the interface and the mobile terminals, the method including providing a first messaging stage between said mobile terminals and the server, and providing a second messaging stage between the server and the interface whereby to control delivery of data packets via the server to all or to a selected group of the mobile terminals.

2. A method as claimed in claim 1, wherein each message is provided with an identifier indicative of the type of message contained in the packet.

3. A method as claimed in claim 2 wherein said packet contains a broadcast message.

4. A method of routing packet data substantially as described herein with reference to and as shown in the accompanying drawings.

5. An arrangement for routing packet data from a packet data network to mobile network subscriber terminals served by a mobile switching centre, the arrangement including an interface means between the mobile network and the packet network, a server disposed between the interface and the mobile terminals, first means for providing messaging between said mobile terminals and the server, and second means for providing messaging between the server and the interface whereby to control delivery of data packets via the server to the mobile terminals.

6. An arrangement for routing packet data substantially as described herein with reference to and as shown in the accompanying drawings.