Mobile telecommunications system.

(57) Abstract

Thii invention relate »to a leleconununieations system including a plurality of mobile telephones. The telecommunications system has a switch network including: data storage unitx (HLR) for «oring connection data reltüng to respective mobile telephones; a register (15) for storing association * between tbe data storage unite aud respective Identification code; inputs for inpotting an Identification code; and a switch unit (30, 31) for lotenogating the regiater (15) to determine the dato storage unk (HLR) aisociated with that Identification code. The switch network tfcen use * tbe connection data stored by the data storage utit (HLR) to form a telecoramunicatkm llnk with the corresponding mobile telephone. The assodations stored by the register (15) can be changed.

Printed (rom Mimosa

TELECOMMUNICATION SYSTEM

Background of the Invention

Field of the Invention

The present invention relates to a telecommunication system. The present invention is particularly, but not exclusively, concerned with a telecommunication system for mobile phones.

Summary of the prior art

In standard terrestrial telecommunication systems, calls are routed from one fixed point to another and it is therefore relatively straightforward to determine a switching route for such calls. The originator of the call enters information into the system (usually the destination phone number) in which the routing information is arranged sequentially. Thus, it is relatively straightforward for the system to determine the necessary switching to achieve the prosecution, by successively decoding the parts of the entered information. Any switching point needs to consider only part of the information.

When the telecommunication system involves mobile phones, the situation is more complicated because a call to a mobile phone is not to a fixed point, and therefore the location of the destination must be determined by the system. Currently, a call to a mobile phone results in REF: 24344

-2a signal is transmitted to a Domestic Location Register (HLR) unit, which determines the location of the mobile phone, and thus allows the routing of the call to be presented.

Inevitably, HLRs have limited capacity, and some arrangement is therefore necessary to allow telecommunication systems to have access to multiple HLRs. At first glance, all you need is for a plurality of HLRs and different mobile phone numbers to be provided to different HLRs.

However, this is not consistent with the goal of providing customer flexibility in a mobile phone system. Each mobile phone has two types of numbers associated with it, one is the number which third parties use to call the mobile phone (an "MSISDN") and the other is an identity number (an "IMSI"), the which is used by the telecommunications system to direct the mobile phone. When using existing techniques, information that relates to both of these numbers must be stored in the same HLR.

It is contemplated that users may need multiple MSISDN numbers, for example, if a user is to have voice and data communication capabilities, in existing systems, any second MSISDN number with a Common Identity Number (IMSI) must be a MSISDN number of the same HLR as the previous MSISDN. This might be impossible to achieve if, for example, the HLR containing the original information is full. So the only way that additional services could be provided, which would require the user to change the phone number, which would be undesirable.

-3This becomes a particular problem if it is desirable for users to have the ability to select their numbers, rather than be provided with them.

Brief description of the invention

To overcome these problems, the present invention proposes that the switching network, which connects users to other users, HLRs and system services, has a registration unit associated with it, which registration unit contains information related to each telephone number to a corresponding one of a plurality of HLRs. The relationship between the telephone numbers and the HLRs should then be freely selectable within the registration unit, such that the registration unit acts as a converter between the number and the information identifying the HLR.

By providing such a registration unit, the fixed relationship between the numbers and the HLRs is broken and any number can be assigned to any HLR, assuming space permits.

The registration unit can also store additional information, associated with mobile phones, which allows the switching network to allow calls from mobile phones to be routed to different services, depending on the mobile phone, the caller itself, in addition to the number dialed .

As a first example, different mobile phones provided by different organizations (service providers) could use the same generic access code, for example 150, to call the Provider of

-4 Original service regarding billing inquiries, for example. It is convenient, if you have access to such services by numbers, which are independent of the organization that provides the service. Then, a call from a mobile phone to such a service activates a signal to the registration unit, which generates information, which identifies the service unit associated with that number for the particular mobile phone. That identifying information can then be passed back to the switching network, to allow the call to be routed to the correct service unit.

As a second example, users could have the ability to access voicemail in respective personal mailboxes by dialing a second generic access code, say 123, the record provides the information necessary to route the call.

In any case, the system can be adapted in such a way that if the user is using a public telephone, instead of his own mobile phone, he can manually transport to the switching network, enough information for the switching network to obtain from the registry the additional information associated with the user's mobile phone.

An additional possibility is that the registry uses additional information concerning mobile phones in relation to calls to phones, rather than from phones. For example, the additional information may be sufficient to redirect a telecommunication link originally intended for a given mobile phone, if that phone is not available, perhaps because it is connected or inoperative, or because its owner

-5 does not answer. Such a system for example, may be able to function in such a way that if a person tries to contact a mobile phone which is not available, the switching network may redirect the call to an appropriate service, such as a mail service. voice.

By using the present invention, many advantageous features of the telecommunication system can be achieved. If there is a fault with the mobile phone unit, which identifies the mobile phone (that unit is referred to as a SIM), it should be possible to replace that unit quickly. With the present invention, even if the new identity number

IMS! provided to the user is related to a different HLR from the previous IMSI identity number, the user does not need to change his phone number (MSISDN number), since reassignment to the new HLR can be accomplished through the registration unit.

From here, any phone number (MSISDN number) can be transformed to any user identity.

An embodiment of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic block diagram of a telecommunication system incorporated in the present invention;

Figure 2 shows part of the telecommunication system of figure 1 in more detail.

-6 Detailed description

Referring first to Figure 1, a switched network 10 interconnects land and mobile phones. If a call is made to a mobile phone from a land phone, the call is routed or routed via the public switched telephone network (PSTN) 11 to the switching network and from that switching network 10 to! mobile phone (BSS) 12. To do this, the switching network 10 must determine the routing information and, to determine that routing information, must determine the location of the mobile phone 12, which it does via an HLR with which the mobile phone 12 is associated. When there are multiple HLRs 13, 14, it is necessary for the switching network 10 to determine which HLRs 13, 14 should be accessed, based on the telephone number (MSISDN number) of the mobile phone entered by the originator of the call.

In accordance with the present invention, the switching network 10 has access to a registration unit 15, which identifies the called number and directs it to a particular HLR 13, 14 with which the mobile phone 12 is associated. The registration unit 15 allows the relationship between any mobile telephone number and the HLRs 13, 14 to be freely determined, such that the number is not affected by the particular HLR 13, 14 with which it is associated. The registration unit 15 eliminates the need for a particular mobile telephone number to be associated with a fixed HLR 13, 14.

Once the particular HLR 13, 14 with which the mobile phone 12 is associated has been identified, signaling can be presented to that

-7HLR, and the information derived from it, in the usual way. This information is used to "establish" the call to the mobile phone 12, which can then be routed to the destination phone as normal.

Similarly, if a call originates from the mobile phone 12, the switching network 10 must again determine the routing of that call. If the call is to a terrestrial telephone connected to the switching network 10 via the PSTN 11, then this routing can be based on the telephone number of the destination number, in the normal way.

If a call is made from a mobile phone 12 to one of a plurality of voice processing systems 16, 17 or to services 18 associated with the switching network using a short code (eg 123), the relationship between the phone 12 mobile and the corresponding service must be determined by the registration unit 15, before the switching network can determine the appropriate voice processing system 16, 17 or the services 18 to which it must have access.

It should be noted that the existing systems are similar to the arrangement shown in Figure 1, but without the registration unit 15, and with only one

Individual HLR. Such existing systems do not need to determine which HLR is to be accessed since there is only one such HLR. To achieve the present invention, the switching network 10 accesses the recording unit 15 when handling any calls that would result in a signaling interrogation to the HLR in the existing arrangements, to determine which of the multiple HLRs 13, 14 is going to have access. Hence, the present invention is δ

this can be accomplished by providing the registration unit 15 and proper programming of the switching network 10.

Figure 2 shows the switching network 10 in more detail. It will have a plurality of mobile switching centers (MSCs) 20, 21 and 22 and a call destined for any given mobile phone results in signaling between that MSC 20-22 and one of a plurality of signaling transfer points (STPs). 30, 31, which points to the registration unit 15 to determine the HLR 13, 14 which is appropriate to the mobile phone 12. The registration unit 15 determines that information of the telephone number (MSISDN number) of the mobile telephone 12. It would then be possible for the recording unit 15 to send the signal directly to the appropriate HLR 13, 14 but, as shown in Figure 2, it is preferable that the information be passed back to the corresponding STP 30, 31, which then passes signaling to correct HLR 13, 14.

A similar signaling flow is seen when the mobile phone user tries to access one of the voice processing systems (VPS) 16, 17. The call is received by one of the MSCs 20, 21 and 22 which make pass dialed digits and mobile phone identity to one of STP 30, 31, 32. It relays the information to the registration unit 15, which uses this information to construct the correct address of the appropriate voice processing service (VPS) 16, 17. That information is relayed back from the registration unit via one of the STP 30, 31, 32 to the original MSC 20, 21, 22. This address is then used to route the call

-9 through the switching network 10. That routing routes the call from the appropriate MSC 20, 21, 22 via the switching network (comprising the transit switching centers, TSC 32, 33} to the appropriate VPS 16, 17.

The signal, which a mobile phone passes to the switching network and by which the mobile phone is recognized, does not need to be fixed, but can be alterable, for example by inserting a card that carries data into the phone .. Thus, a user can identify himself to the switching network by inserting a personal card, which identifies him, into a mobile phone, and subsequent channeling to an appropriate VPS can be carried out based on the identity of the user.

The ease of channeling calls to the VPS by using information in the registration unit 15 will allow individual voice processing services (such as mailbox accounts) to be located at sites which have the closest geographical proximity to where the telephone mobile will be located predominantly. This can dramatically reduce the cost of transporting the call.

Furthermore, if the predominant location of the mobile phone changes, such that it is more convenient to use a different VPS 16, 17, then this change can be accommodated in the registration unit 15. The subscriber of the call can still access their VPS account (although now hosted by a different platform) without changing the number used to call the service. Similarly, if the mobile phone user changes from one service provider to another, the registration unit 15 can compensate for this change without the user

-1010 have to dial different numbers. Thus, for example, when there are several service providers and the mobile phone user changes from one service provider to another, the user does not need to dial different numbers to contact the new service provider. Instead, the same numbers can be used and the new call routing is controlled by the signals that are passed between the MSC 20, 21, 22 and the registration unit 15.

The switching network 10 can also use the information about the mobile phones, such that if a given phone is connected, unanswered or inoperative, the answering network can redirect calls originally directed to that phone to an appropriate VPS, such as a voice message system.

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