Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Patent
1997-08-27
1999-12-21
Eisenzopf, Reinhard J.
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
455432, 455461, H04Q 720
Patent
active
060060948
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to routing an international call, e.g. from a PSTN subscriber, to a mobile subscriber having a home PLMN in a foreign country.
BACKGROUND OF THE INVENTION
The modern mobile telecommunications network offer a new attractive feature: roaming between several operationally independent public land mobile networks (PLMN). Roaming between PLMNs in different countries is called international roaming. Normally a mobile subscriber has a subscription relationship with a single PLMN. This specific PLMN is called the home PLMN of the mobile subscriber. Service can be obtained also from other PLMNs, depending among other conditions on subscriptions. For example a mobile subscriber who has a subscription relationship with a national PLMN in Finland may also make outgoing calls and receive incoming calls through another PLMN for example in Germany, if there are agreements between the operators of the two PLMNs. The other PLMN is sometimes called visited PLMN. One example of a standardized system supporting international roaming is the pan-European digital mobile radio system GSM (Global System for Mobile Communications) and its modification DCS1800 (Digital Communications System). The GSM supports both mobile station roaming in which a mobile station moves from one PLMN to another, and a subscriber identification module (SIM) roaming in which only a SIM moves. The latter may allow also roaming between PLMNs having incompatible radio interfaces, such as different operating frequencies.
A significant disadvantage that makes the international roaming less attractive is the cost of the international calls. Typically a calling party is charged for the first half of the routing to the home PLMN of the called mobile subscriber, and the called party is charged for the second half of the routing from the home PLMN to the visited PLMN. Thus, the called party has to pay the expensive international call charges also for calls which he/she does not want to receive at all. The expensive call charges will discourage the mobile subscriber from extensively using the roaming service. Actually, it is believed that most of the mobile subscribers will have incoming call barried while roaming.
In the international calls originating from the roaming mobile station, the routing of the call is always optimized. However, routing of the call destinating to a roaming mobile station is not optimized, and consequently, double international legs and very high international call charges may unnecessarily arise. This problem will be explained by means of an example with reference to FIGS. 1 and 2.
In FIG. 1 a PSTN subscriber in Australia makes an international call to a mobile station MS having a home PLMN in Germany and being currently located in the home PLMN. The PSTN subscriber dials a prefix 0011 and the mobile station ISDN number MSISDN including a country code CC, a national destination code NDC and a subscriber number SN. The prefix 0011 is an international call code in Australia, and consequently, the local PSTN exchanges route the call to the international PSTN gateway in Australia. The international PSTN gateway routes the call to a destination country, i.e. Germany, according to the country code CC. The international PSTN gateway in Germany will route the call to the gateway MSC in the home PLMN of the called MS according to the national destination code NDC. The gateway MSC interrogates the home location register HLR of the called MS according to the NDC SN and then route the call to the called MS according to the mobile station roaming number MSRN obtained via the HLR. In the above case the PSTN subscriber will pay charge for the whole call.
In FIG. 2 it is assumed that the called MS is roaming in a visited PLMN in Australia. Similar to the above case in the first half of the routing, the call is first of all routed to the home country and the home PLMN of the called MS. The mobile station roaming number MSRN is then obtained via the HLR and the call will then be routed to the MS in A
REFERENCES:
patent: 5109408 (1992-04-01), Greenspan et al.
patent: 5210787 (1993-05-01), Hayes et al.
patent: 5408419 (1995-04-01), Wong
patent: 5610974 (1997-03-01), Lantto
patent: 5734700 (1998-03-01), Hauser et al.
Beller, Call Delivery to Portable Telephones away from Home using the Local Exchange Network, IEEE International Conference on Communications, vol. 2, Denver US, pp. 948-953, Jun., 1991.
Brini, et al: "International roaming in digital cellular networks", CSELT Technical Reports, vol. 20, No. 6, Dec. 1992, pp. 532-533, figure 1b, abstract.
Barbetta et al: "Interworking issues in international UPT service", CSELT Technicals Reports, vol. 21, No. 4, p. 833-41, Oct. 1993, Dialog Information Services, File 2, INSPEC Abstract No.: B9403-625OF-067.
Appiah Charles N.
Eisenzopf Reinhard J.
Nokia Telecommunications Oy
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