Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-06-25
2003-02-04
Le, Thanh Cong (Department: 2684)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S435100, C455S458000
Reexamination Certificate
active
06516193
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method and arrangement for controlling the local operation of a mobile station. A mechanism for restricting connection of a mobile station to a cell will be disclosed as one embodiment of controlling the local operation. The invention also relates to a mobile station, data base, subscriber register, location updating method and handover method.
In cellular mobile communications systems, a mobile station may roam freely within the area of the mobile communications network and connect to the base transceiver station signal received best at a given time. Usually, all base transceiver stations provide substantially similar services for the mobile stations in a network. Some base transceiver stations can, however, be defined to provide a certain special service for all mobile stations of the network, e.g. call charges below the normal tariff. The base transceiver station broadcasts a message on such a special service on its broadcast control channel (BCCH), whereby mobile subscribers in the area note that they are within a special service area of the network and may take advantage of this service.
FIG. 1
shows a simplified block diagram of the structure of the pan-European GSM system. The mobile station MS is connected via a radio path to a base transceiver station BTS; in the case shown in
FIG. 1
to the base transceiver station BTS
7
. An idle mobile station MS receives transmission from the base transceiver station selected by it. A base station subsystem BSS comprises a base station controller BSC and base transceiver stations BTS under its control. Usually, there are several base station controllers BSC under a mobile services switching centre MSC. The mobile services switching centre MSC is connected to other mobile services switching centres, a gateway mobile services switching centre GMSC and possibly to an intelligent network IN. The GSM network is connected to other networks through the gateway mobile services switching centre GMSC, such as the public switched telephone network PSTN, another mobile communications network PLMN, ISDN network or intelligent network IN.
The subscriber data of the mobile station MS are stored permanently in a home location register HLR of the system, and temporarily in the visitor location register VLR in the area of which the mobile station is located at a given time. The location information of the mobile station MS is stored in the visitor location register VLR with an accuracy of a location area LA. The geographical area controlled by the visitor location register is divided into one or more location areas LA, within each of which the MS may roam freely without notifying the VLR. Within each location area there may be one or more base transceiver stations BTS in operation.
Base transceiver stations BTS continuously broadcast information on themselves and their environment on their broadcast control channel, e.g. the cell identity CI, information on neighbouring cells and the location area identifier LAI. On the basis of the LAI, the mobile station MS receiving broadcast transmission from the base transceiver station BTS knows in which location area LA it is at a given time. If the mobile station MS notices, on changing the base transceiver station BTS, that the location area identifier LAI of the base transceiver station has changed, it sends a request for location updating to the network. The location area of the mobile station MS is updated to the visitor location register VLR in the area of which the mobile station is at a given time. Information on the VLR covering the area where the MS is located is transmitted to the home location register HLR.
The mobile station MS continuously measures signals of the base transceiver stations BTS located nearest to the cell within which the mobile station is located e.g. to determine the base transceiver station providing the best signal and to be prepared for a possible handover. The mobile station identifies the neighbouring cells it is to monitor on the basis of the information on neighbouring cells transmitted by each base transceiver station on its broadcast control channel. For example, in the GSM system the mobile station MS can simultaneously measure the signal level and/or quality of a maximum of 32 other base transceiver stations in addition to the serving base transceiver station. When roaming within the mobile communications network, the mobile station MS usually connects to receive the base transceiver station BTS having the strongest signal. Thus an effort is made to set up a call terminating to a mobile station MS or a call originating therefrom primarily through this base transceiver station BTS.
In mobile communications systems, location information on the MS is needed for routing incoming calls and for other network services.
FIG. 2
of the attached drawings shows by way of example location updating triggered by the mobile station MS as a signalling chart. The mobile station MS requests a signalling channel from the base transceiver station BTS for location updating and sends a request for location updating (message
21
) on the assigned channel. The request is transmitted to the mobile services switching centre MSC. The mobile services switching centre MSC forwards the request for location updating to the visitor location register VLR in message
22
. In step
23
, the authenticity of the subscriber is verified (known as authentication) e.g. to control the access to the network and to prevent abuse. In authentication, information stored in the network is compared with information stored in the mobile station MS. After a successful authentication the new visitor location register VLR transmits a message
24
on location updating to the home location register HLR of the mobile station. The home location register HLR acknowledges location updating by sending the necessary mobile subscriber data (message
25
) to the visitor location register VLR. In step
27
, information on the protection algorithm that will be used is transmitted to the mobile station MS. The visitor location register VLR informs of completion of location updating in message
28
. The mobile services switching centre MSC forwards this message to the mobile station MS in message
29
. Messages
28
and
29
also include the new temporary mobile subscriber identity TMSI assigned to the mobile station MS by the visitor location register VLR. After completion of location updating, the signalling channel used is released. In addition to the location updating signalling described above, the visitor location register VLR, if necessary, also inquires the identity of the mobile station and requests authentication keys of the mobile station and other necessary subscriber data either from the previous visitor location register of the mobile station or from the home location register HLR.
A problem associated with the above-mentioned embodiment for providing special services in a network is that both base transceiver stations providing special services and base transceiver stations providing standard services have to serve all the mobile stations entitled to use the network substantially in the same way. Hence it is not possible to provide tailored special services to which other mobile stations are not entitled for individual mobile stations or for a mobile station group. A problem associated with prior art mechanisms of the embodiment in which controlling of the local operation comprises restricting connection to a cell is that the restriction covers the whole network, and thus the mechanisms are not suitable for locally restricting the use of a mobile station.
BRIEF DESCRIPTION OF THE INVENTION
An object of this invention is to create and utilize subscriber-specific or subscriber-group-specific localised service areas. Localised service areas allow to provide some locally tailored special service, e.g. call charges below the normal tariff. Alternatively, or additionally, connection of a mobile station to a network can be restricted locally.
This new kind of control
Kokkola Tommi
Salmela Seija
Tuohino Markku
Vuoristo Sirpa
Cong Le Thanh
Nokia Telecommunications Oy
Pillsbury & Winthrop LLP
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