FI99190B - Method and arrangement for controlling network access in a cellular mobile telecommunications system - Google Patents

Description

99190

A method and arrangement for controlling network access in a mobile communication system

The invention relates to a method for controlling network access 5 in a mobile communication system, the method comprising the steps of a mobile subscriber sending a location update request; the location update request is forwarded to the visitor location register serving the location area of the mobile subscriber; the visitor register detects that the mobile-10 ink subscriber is a new subscriber in its territory; the visitor register sends a location update request to the mobile subscriber's home register, which contains the visitor register identifier.

The Global System for Mobile Communication (GSM), a pan-European digital mobile communication system, is designed to allow users to move very widely, both on their own network and on the network of other operators in the same country or in other countries. In other words, a mobile subscriber can have full access to services in many countries through a single space-20 relationship.

In Europe or worldwide. Such a possibility to move within a mobile network or between different mobile networks is called roaming. The mobile networks of different 0 · I operators are referred to herein as «· · I. *. 25 PLMN (Public Land * i Mobile Network). The PLMN is typically confined within the borders of a single country, in addition to which each country may ...: have several mobile networks, the coverage areas of which may »» · * partially or completely overlap.

30 A mobile subscriber has a subscriber relationship to one mobile network PLMN, called the subscriber's home PLMN. As stated above, a mobile subscriber can. receive service also from other mobile networks PLMN, ψ · · depending on e.g. local conditions. In other words, the operator of the home PLMN • · '·; · * 35 can offer its customers different road service areas according to the customer's needs. • · 9 · »• I» • ♦ ·· »* · • * 2 99190. For example, the operator may provide a subscriber option in which the subscriber relationship is limited to a particular portion of the PLMN, the entire PLMN, or in addition to a portion or all of the other PLMN-5 networks. In this context, the foreign PLMN in which the mobile station roams is called the visitor PLMN. Roaming involves having a mobile subscriber with a device that allows him to access different networks. This device can be either the mobile station 10 itself or alternatively a subscriber card or module, such as a SIM (Subscriber Identification Module) of the GSM system, which can be placed in any mobile device.

In the GSM system, the subscriber data of the mobile subscriber is permanently stored in the home location register HLR of the home PLMN network. The HLR also contains information on the area of the visitor location register VLR in which the mobile station is currently located. A VLR is a second subscriber register associated with one or more mobile switching centers, each of which controls a set of cells. Predetermined cell groups within the 20 VLRs form location areas. When the mobile station changes the location area, it sends a location update request to the VLR. If this new location area is in a different VLR area than the previous location area, i.e. the mobile subscriber is a new subscriber in the VLR area, the new VLR sends a location update request to the mobile station's home location register HLR. Normally, the HLR returns the necessary subscriber information to the visitor location register VLR. Subsequent *, V location updates within the same VLR range do not cause location updates to the home location register HLR.

30 However, such freedom of movement requires ... procedures in the mobile communication system to control access to the network and to prevent various abuses. Such procedures include e.g. subscriber '' · authentication. In addition, the VLF will take care of the possible regional restrictions on mobile subscribers in the VLR area. In the GSM system, the SIM module has a space reserved in the memory for a list, which may include four PLMNs prohibited from the mobile subscriber. This list can be updated whenever a new PLMN does not accept a location day-5 attempt. The data in the list is processed in the order of entry, so the oldest data entered is deleted when the list is full. The mobile station will not attempt to update the location to the PLMN in this list without manual forced control of the subscriber.

10 The home location register HLR, on the other hand, may deny a new location update request from the new visitor location register VLR .. if the mobile subscriber is not entitled to service in that VLR area. This prohibition may be due, for example, to the fact that the VLR belongs to a PLMN network with which the operator of the ko-15 ti-PLMN does not have a roaming agreement.

However, both network operators and users are interested in a more flexible and diverse geo-restriction of services. For example, companies may need sal-20 employees to have different call rights depending on their areas of operation. It may be interesting for the operator to offer subscriber relationships in different coverage areas and at different prices. However, such space-specific coverage requires effective network access control and quickly leads to large amounts of data that are difficult to maintain and manage in mobile communication systems.

It is an object of the present invention to provide a network access method and arrangement which can be used to implement versatile and flexible subscriber-specific network access control in an easily manageable and off-system manner. he changes in a demanding way.

• · 9 · This is achieved by a method of the type * · described in the introduction, which is characterized according to the invention, «· · ... · 35 that 4 99190 of the banned visitor registers from the mobile subscriber are maintained in the home directory on a per-subscriber basis; the home registry, upon receipt of the mobile subscriber's location update request from the visitor location register, checks whether the visitor location register is one of the prohibited visitor registers from that travel subscriber; the home location register denies the location update if the visitor location register is among the forbidden visitor registers.

The invention also relates to an arrangement for controlling access to the network-10 in the home location register of the mobile communication system in connection with a location update request received from the mobile subscriber register, which arrangement accepts or rejects the location update depending on whether the mobile subscriber is entitled to the visitor-15 register services. According to the invention, the arrangement is characterized in that the home register contains a list of prohibited visitor registers; the subscriber data of the mobile subscriber has an index indicating the prohibited visitor registers of the mobile subscriber from said list; the home location register is adapted to check whether the visitor location register that sent the location update request is among the visited and location registers indicated by the mobile subscriber index and to deny the location update if • ·. the visitor register is among the banned ones.

The purpose of the subscriber-based network access according to the invention is to make it possible to prevent mobile communications - large-scale roaming by defined visitor registry areas in a foreign network, and if necessary also in the home network. For this purpose, it is possible to select "forbidden" visitor registers for each mobile subscriber in the subscriber data of the home directory. Prohibited visitor registry: 1. The definition is not controlled by the * · operator of the mobile subscriber's home network. Subscriber-based network access may be an optional feature, in which case not all mobile subscribers need to have the definition of prohibited visitor registers in the subscriber data. • · * 1 • · • · 1 · · 5 99190. Upon receipt of the location date request from the visitor location register, the home location register checks whether the roaming is allowed to the mobile subscriber in that visitor location area. This is done by retrieving the list of forbidden visitor registers defined for the mat-5 mobile subscriber and checking whether the visitor register that sent the location update request is among the forbidden visitor registers. If the visitor register is denied to the mobile station, the location update is denied, which prevents the mobile subscriber from accessing the mobile communication system from the area of that visitor register. In the invention, only an index referring to a common list of prohibited visitor registers for all subscribers is included in the subscriber data of the mobile subscriber. This index is used as a key to obtain from the list the forbidden visitor registers defined for the mobile subscriber in question, against which the visitor register that sent the location update request is compared. The length of the index depends on the Great u-20 decta and implementation of the list of prohibited visitor registers, being preferably one or two words. The memory capacity required by the list, in turn, depends on the number of prohibited visitor registers. The use of the index significantly reduces the required memory capacity, facilitates the maintenance and management of subscriber-based restrictions for the operator, and speeds up the check in connection with the location update. In the preferred embodiments of the invention, two alternative ways are used to index the prohibited visitor registers: a bitmap for the subscriber and a prohibition table. In the first u-.pair for each ti-. a bit map is broadly defined, with each bit position • ·; ·. refers to one forbidden network. Visitor registers that are prohibited in the bitmap are marked with a specific bit space.

: The advantage of this solution is an individual blocking table for each subscriber. In the Prohibition Table, each row contains 9 · • · • · • · ·· ♦ · • ♦ 6 99190 groups of prohibited visitor registers. Each subscriber has an index on the line or lines that need to be checked during the location update. That is, different packets of 5 forbidden visitor registers are defined in the ban table, and one or more packets are used to restrict visitor registers per subscriber. In the bitmap embodiment, the length of the bitmap, limits the number of forbidden visitor registers to 16 visitor registers / word. On the other hand, extending the word length of a 10-bit map rapidly increases the need for memory capacity. In the prohibition table, the word length of the index limits the number of different combinations.

The invention will now be described by way of preferred embodiments with reference to the accompanying drawing, in which Figure 1 is a signaling and block diagram of a mobile communication system according to the invention in which a home directory controls network access using a bitmap-based Fig. 3 shows a prohibition table, Fig. 1 a signaling and block diagram of a mobile communication system in which the home register implements network-I; 25 access control using the indication of prohibited visited registers based on the ban table.

*

The present invention can be applied to any mobile communication system in which a location update is performed on a database in the home network of a mobile subscriber, referred to herein as a home location register, when a mobile station makes a location. . update to another subscriber database in the territory of which it is temporarily visiting. The invention will now be described m m · using, as an example, the pan-European digital mobile communication system GSM (Global System for ψ ψ · * * * * • * • · 7 99190

Mobile Communications). However, the invention is not intended to be limited to this particular system.

In mobile networks, the geographical area covered by the network is divided into smaller radio areas, i.e. cells 5, so that while in the cell, the mobile radio station, i.e. the mobile station MS, communicates with the fixed network via a fixed radio station, i.e. base station BTS. The mobile stations MS are free to move from one cell to another. However, the mobile network must know the location of the MS in order to route incoming calls to the mobile station or for other reasons to retrieve this. Typically, a mobile network knows the location of a mobile station with the accuracy of an area formed by one or more cells, called a location area. When the mobile station, based on the information received from the base stations, detects a change in the location area, it initiates a location update by sending a location update request to the mobile network. Location update causes the mobile subscriber information to be updated in the mobile network subscriber database. In the GSM system 20, these subscriber databases are the home location register HLR and the visitor location register VLR. The home location register HLR is a database that permanently stores a mobile subscriber. subscriber information and information on which visitor register; . In the VLR area, there is a mobile station at any given time. The VLR is a subscriber database to which the necessary information about the mobile subscribers in the area of the VLR is temporarily copied from the home location register HLR. In addition, the VLR stores information about the current location area of the mobile station. When the visitor location register VLR receives a location update request from a new mobile subscriber in its area, it sends a location update request to the mobile subscriber's home location register HLR to obtain the necessary subscriber information. This location update request includes the mobile subscriber ID • · · 35 as well as the VLR country code CC and the national • · • · · • ··

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• · 8 99190 item code NDC. Normally, if the mobile subscriber has no restrictions, the home location register HLR accepts the location update and returns the necessary subscriber information to the visitor location register VLR.

According to the present invention, the mobile wide area network (HPLMN) operator has the possibility to select a set of "forbidden" visitor registers VLR for each mobile subscriber and place the list containing them in the home location register HLR. The purpose of this list is to make it possible to prevent mobile subscribers from roaming in certain VLR areas. Prohibited visitor registers VLR is assigned on a per-subscriber basis and not all subscribers need to have any prohibited areas at all. Upon receiving the location update request, the HLR uses the subscriber information of the mobile station 15 to check whether roaming of the mobile station in that VLR area is allowed. This check is based on the CC and NDC codes included with the location update message, which identify the VLR of the visitor location register that sent the location update. If the VRR of the visitor register 20 belongs to the prohibited registers of the mobile subscriber in question, the HLR denies the location update. This prohibition may be sent as a negative acknowledgment,. with the error code "roaming not allowed".

• ·. In the preferred embodiments of the present invention, only an index referring to the list of forbidden visitor registers VLR is placed in the subscriber data of the home location register HLR in the subscriber database of the mobile subscriber. Thus, only one such list is needed in the home directory and only 30 short indexes in the subscriber data for each mobile subscriber, which results in significant memory capacity savings for large subscriber numbers. and / or VLRs. The following are • · two possible implementations for indexing that show 'forbidden VLRs from said list: 1) a bitmap for each * * · 35 mobile subscriber and 2) an indexed forbidden pause • »i · · i ·· * * * · 9 99190 lock.

Bitmap

An embodiment of the invention based on the use of a bitmap will now be described with reference to Figures 1 and 5. In Figure 1, the home subscriber's home network HPLMN home register includes an HLR controller 11, a subscriber database 12 and a forbidden visitor location VLR file 13 for each mobile subscriber. each bit-10 droplet refers to one record in a file that contains the NDC and CC codes of the forbidden visitor registers. Figure 2A illustrates, by way of example, a bitmap containing 32 bits and Figure 2B a file of forbidden visitor registers comprising 32 records. Bit position 0 of Fig. 2A indicates the first record in the file of Fig. 2B, bit position 1 the second record, etc. A certain logical state of a bit in the bit position of the bitmap, e.g., "1", forms a flag indicating the VLR of the visitor register in the corresponding record is forbidden. If the bit in the bit-20 has another state, e.g. "0", the VLR in the corresponding record is not prohibited. In Fig. 2A, the flagged bit positions are marked with an "x", i.e. ·, i.e. the bitmap of Fig. 2A marks data as prohibited. visitor registers in 0, 3, 26, 28, 29 and 31 • · m 9. * 25 VLR. In the example of Figure 2A, the bitmap comprises two words and can thus indicate 32 VLRs. Bit- • · ·: · * maps are placed in the subscriber database. 12 per subscriber.!: * Sesti. The file of Figure 2B is located in block 13 of Figure 1.

· ·. ·: The operator can create bitmaps, delete bitmaps 30, and modify bitmaps in the subscriber database 12. Similarly, the operator can modify records in file 13. Each record contains the CC-9 \ and NDC codes of the forbidden visitor register.

9 »··· The location update in the arrangement m 35 according to Fig. 1 is as follows. When the mobile subscriber makes a location update to the visitor location register VLR of the foreign network VPLMN (or the HPLMN of the home network) for the first time, the VLR sends a location update request (l) to the mobile subscriber's home location register HLR, which includes CC and NDC codes 5 and a mobile subscriber ID. Based on the received mobile subscriber ID, the HLR controller 11 retrieves from the subscriber database the bitmap (2) and (3) assigned to the mobile subscriber, if the mobile subscriber has a bitmap. Thereafter, the HLR controller indicates the prohibition file 13, step (4), with the received bitmap 10, step (4), and receives the VLR codes NDC and CC of the prohibited visitor registers from the mobile subscriber, step (5). The HLR compares the VLR codes NDC and CC of the new visitor register that it received in the location update message f 1) with the codes NDC and CC received from the file 13 15, and if one of them is the same, the new VLR belongs to the prohibited visitor registers from the mobile subscriber. In this case, the HLR controller 11 denies the location update and sends a negative acknowledgment (6) to the new visitor location register VLR in the form of an error code-20 din "roaming not allowed". If the new VLR is not among the forbidden visitor registers, the HLR controller 11 accepts the location update and sends the necessary ti-. extensive information for the new VLR.

Prohibition Table The assignment of prohibited VLRs based on a prohibition table is described below with reference to Figures 3 and 4. In this embodiment of the invention, a table is defined in which each row (or column) contains a plurality of prohibited visitor registers VLR. Figure 3 shows an example of such a table.

A. The table in Figure 3 has y rows or lists, each with x forbidden visitor registers VLRs, denoted by the symbol NW. The number l-y of a row or M · ,,, * 35 list forms an index that can be used to indicate the desired row or list in the table. 9 · • · «· • · ·« ·· • · 11 99190. Prohibited visitor registers are defined for a particular subscriber by indexing in the subscriber data the number of the line or lines containing the desired combination of prohibited VLRs of the prohibited vie-5 rail registers. Prohibited lock or. thus, common to all home directory subscribers, and in this embodiment, it is not possible to define each forbidden visitor register VLR for each subscriber separately. However, the implementation is advantageous in terms of the need for memory 10, although on the other hand the size of the table limits the number of different combinations.

The use of a ban table in connection with network access control is described below with reference to Figure 4. The mobile subscriber makes a location update to the visitor location register VLR of the foreign network VPLMN (or home network HPLMN) for the first time, whereupon the VLR sends an update request (1) to the mobile subscriber's home location register HLR containing the visitor location CC and NDC codes. The HLR controller 44 receives the location update request (1) and retrieves the subscriber database from the subscriber database with an index of the list of prohibited visited registers, steps (.?) And (3). The HLR controller 44 sends this index and the new CC and NDC codes of the visitor register to the ban table p * 2b process 43, step (4). Process 43 retrieves steps (5) and (6) from the ban table 41 using the index table '' to denote the NDC and CC codes of the visitor registers defined as prohibited for the subscriber. Prohibition Table Process 43

T: compare the VLR codes NDC and CC of the new visitor register

30 ban table attempts for 41 obtained NDC and CC codes. If ', e.g., the compared codes are the same, process 43 sends si- ···. a location update deny message (7) to the HLR controller 44, • · denying the location update to the new visitor location register VLR, step (8). If the codes are not the same in the comparison performed by the prohibition table process, the process p

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• * • · P · 'M' »

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12 99190 43 sends an acknowledgment message to the HLR controller, whereby the HLR controller allows the location update and sends the necessary subscriber information to the visitor location register VLR.

The figures and the related description are intended only to illustrate the present invention. The details of the method and arrangement according to the invention may vary within the scope and spirit of the appended claims.

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Claims (9)

13 99190 1. A method for controlling network access in a mobile communication system, the method comprising the steps of 5 a mobile subscriber transmitting a location update request, maintaining subscriber-specific information about the banned visitor registers from the mobile subscriber, the home registry, upon receiving a request for updating the location of the mobile subscriber-20 from the visitor register, checks whether the visitor register belongs to the group of prohibited visitor registers from that mobile subscriber. size, m home registry prohibits location update if 25 visitor registers are among the prohibited visitor registers. A method according to claim 1, characterized in that: the home directory maintains a list of prohibited visitor registers, the home registry maintains an index for said list in the subscriber data of the mobile subscriber,. the home registry, after receiving the mobile subscription / location update request, visited the registry East, · 1 35 uses the index in the mobile subscriber's data in question to • m * mm * · 9 14 99190 from that mobile subscriber among the forbidden visitor registers, the home registry denies the location update if the visitor registry is among the forbidden visitor registers. A method according to claim 2, characterized in that the home registry maintains a table indexed with different groups of prohibited visitor registers, the home registry maintains an index in the mobile subscriber data referring to one or more groups in said table, the home directory, after receiving the subscriber data of the mobile subscriber, the home registry retrieves the group or groups of prohibited visitor registers indicated by the index from said table, the home registry checks whether the visitor register that sent the location update request belongs to the retrieved travel database. to the group or groups of banned visitor registers • «ml 25, * the home registry denies the location update if • · the visitor registry is among the banned visitor registers. · ·; ί A method according to claim 2, characterized in that the subscriber data of the mobile subscriber is maintained; a bitmap in which each bit points to one visitor register in the list of forbidden visitor registers «· ··: such that when the bit is in a predetermined logical • · · ... * 35 state, that visitor register is forbidden to travel • · · · • · · * · • · 15 99190 from my message, the home register, after receiving the mobile subscriber's location update request from the visitor register, retrieves from the list of forbidden visitor registers the visited 5 registers corresponding to the corresponding bit from the mobile-10 subscriber to the group of forbidden visitor registers, the home registry denies the location update if the visitor registry is among the forbidden visitor registers. Method according to one of the preceding claims, characterized in that the list of prohibited visitor registers includes the country codes (CC) and the national destination codes (NDC) of the visitor registers. 6. Arrangement for controlling network access in the home directory of the mobile communication system in connection with a location update request received from the visitor register of the mobile subscriber, characterized in that the home location register contains prohibited visitor registers. list of passengers, I the subscriber data of the mobile subscriber has an index, m · · I. '25 indicating the registers of banned visitors from the mobile subscriber from said list, • · · the home registry is adapted to check whether the location update request was sent by the visitor register to the mobile subscriber's index and refuse location update if the visitor register is among the banned ones. .'I '; An arrangement according to claim 6, characterized in that • ·: said list is a table with indexed • * · • · · 35 different groups of prohibited visited registers, • · • · · • · »· 16 99190 said index in the data of the mobile subscriber refers to to one or more groups in that table. An arrangement according to claim 6, characterized in that said index is a bitmap, wherein each bit indicates one visitor register in the list of prohibited visitor registers, such that when the bit is in a predetermined logical state, said visitor register 10 is prohibited from the mobile subscriber. Arrangement according to Claim 6, 7 or 8, characterized in that the list of prohibited visitor registers includes the country codes (CC) and the national destination codes (NDC) of the visitor registers. 9 9 * • · 9 9 9 9 9 9 • 9 9 9 • • · • · 99 · 9 9 9 99 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 999 9 17 99190