Change of service profile of mobile subscriber

Details Change of service profile of mobile subscriber Change of service profile of mobile subscriber

2000-08-14

2004-03-16

Maung, Nay (Department: 2684)

Telecommunications

Radiotelephone system

Zoned or cellular telephone system

C455S414200, C455S418000, C455S407000, C455S433000, C455S456500

Reexamination Certificate

active

06708033

ABSTRACT:

FIELD OF THE INVENTION
This invention concerns changing of the service profile of a mobile station subscriber in a public land mobile network, wherein the subscriber may move freely from one location area to another and wherein there are functions to determine the subscriber's location with at least location area precision.
BACKGROUND OF THE INVENTION
Referring to
FIG. 1
, the following is a brief description of the structure and operation of a public land mobile network (PLMN). The names of network elements are the same as in the known GSM mobile network. Other digital mobile networks include the same network elements as those used in the GSM network. Communication between a mobile station (MS) in a cell and the network takes place via the radio path by way of a base transceiver station (BTS). Base transceiver stations BTS are connected to a base station controller (BSC). One base station controller BSC usually controls several base transceiver stations BTS, which may be chained to one another or cabled directly to the base station controller, as is illustrated in the FIGURE. The geographical area covered by these base transceiver stations is called location area (LA). Each location area has its own unambiguous location area identity (LAI), and the traffic of mobile stations located within the area goes through the base transceiver stations of the area and through the base station controller controlling the location area.
FIG. 1
shows three location areas. The mobile station may move in the location area without any need to update the location information concerning itself.
Several base station controllers are connected to one mobile switching centre (MSC). The entity of location areas under the mobile switching center's control is called the mobile services switching centre area. If the public land mobile network includes several mobile switching centers, then their switching center areas together form a PLMN area, which means the geographical area covered by one network. The network is run by one operator almost in all cases.
The public land mobile network also includes various databases.
In the home location register (HLR), of which there may be several, the in formation on subscribers is stored permanently irrespectively of the current location of the subscriber. The visitor location register (VLR) is nowadays integrated with the mobile switching centre, and it stores subscriber information fetched from a home location register while the subscriber visits the VLR's area, that is, the mobile services switching centre area. For example, in
FIG. 1
, subscriber information relating to mobile station MS located in location area LA is stored in visitor location register VLR located in connection with mobile switching centre MSC.
Location update is always done when the subscriber connects to the network and always when the subscriber moves from one location area to another. Location update may also be done periodically at certain intervals. This is called periodic location update. After the location update the HLR knows the address of that VLR in the relating switching centre area of which the subscriber is located, and the VLR knows the identity of that location area in which the mobile station is located. When the subscriber is moving anywhere in the network, this information will be updated.
Reference is still made to FIG.
1
and also to
FIGS. 2A-2C
.
FIG. 1
is a brief illustration of that numbering information which is essential to the invention and which the different network elements have, as well as the numbers stored on the subscriber identity module of the terminal equipment.
FIGS. 2A-2C
show the contents of numbers.
FIG. 2A
shows the content of the location area identity. The identity is formed by the mobile country code (MCC), for Finland that code is 244, by the mobile network code (MNC), in Finland 91, and by the location area code (LAC). Thus, the operator's location area identities differ from each other only as regards the LAC code. Location area identity LAI is in the memory of base station controller BSC of this area. When the mobile station is in some location area, it has also received location area identity LAI of this location area from the network and it has stored it in its own memory.
The mobile station's SIM module stores the mobile station's connection number (telephone directory number) MSISDN, the contents of which are in accordance with FIG.
2
B. It is formed by the country code (CC), which is 358 for Finland, by the national destination code (NDC), which for the operator “Sonera” in Finland is 40 or 400 and by the subscriber number (SN). What is essential is that a mobile station subscriber may have several MSISDN numbers, because in actual fact the number defines the service used and not the telephone equipment itself.
FIG. 2C
shows an IMSI (International Mobile Subscriber Identity) which is a special subscriber identity number, which is used both for identifying the subscriber and for security purposes. When doing a location update and always when asking for a channel from the network, the mobile station will send its IMSI number to the network, and only after the network and the mobile station have agreed on encryption of the radio link the mobile station will send its MSISDN number encrypted to the network. When doing a location update, the mobile switching centre/visitor location register use IMSI number when asking for subscriber information from the home location register. What is essential is that the subscriber in most cases has only one IMSI number, although there may be several MSISDN numbers. Home location register HLR is the place where these numbers are tied to each other.
Based on the description referring to FIGS.
1
and
2
A-
2
C, home location register HLR always stores the subscriber's connection number
umbers MSISDN, the subscriber's international mobile subscriber identity IMSI and the address of that visitor location register VLR, where the subscriber is located. Besides the subscriber's MSISDN number and IMSI number, the visitor location register also stores location area identity LAI and thus also the location area code of that location area where the subscriber is located at the moment. Mobile station MS stores the MSISDN and IMSI numbers and location area identity LAI. In addition, the mobile station stores the subscriber's encryption parameters. When the MS is moving from location area a to location area b in
FIG. 1
, only the LAC code will chan memories of the mobile station and the base station controller and in the visitor location register. No changes take place in the home location register.
In digital PLMN systems traffic on the radio path is encrypted. For this purpose, an authentication and encryption procedure is performed in the beginning of the call setup using different algorithms and encryption keys. The simplified events in the GSM system are such that the mobile station sends its IMSI identity (or its temporary TMSI identity) to the network. Before traffic starts, authentication is performed by using a special identification algorithm stored in the mobile station as well as subscriber-specific identification key K
i
. In the early part of the authentication, the network sends a random number to the mobile station. Using this and subscriber-specific key K
i
in the module the mobile station carries out an identification algorithm. The mobile station uses the received random number and the K
i
value also for calculating connection-specific encryption key Kc. In this calculation another algorithm is used which is stored in the subscriber identity module. This encryption key is used as a key to a third algorithm which is stored in the subscriber identity module and which is then used for encrypting speech and data transmission over the radio path. With the same values the network performs the same algorithms and thus obtains the same encryption key as the result. Both store the key in their memory.
The mobile station always sends the MSISDN num

Affiliated with

Also associated with

Rating

Change of service profile of mobile subscriber does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Change of service profile of mobile subscriber, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Change of service profile of mobile subscriber will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3278069