FI121495B - Control of a mobile connection's connection to a network - Google Patents

Description

CONTROLLING THE MOBILE INTERFACE INTERNET CONNECTION

The invention relates to controlling the network connection of a mobile communication interface.

A particular object of the invention is to control the network connection 5 of a mobile subscriber in the peripheral areas of a home network, where the mobile subscriber may be connected instead of the home network to a roaming network with which the home operator has a roaming agreement. Such areas are particularly the border regions of the country.

In Finland, for example, there is a large area near the Russian border where the coverage of the Russian mobile networks (field strength) is good also on the Finnish side. In this case, when the mobile station is temporarily obstructed with respect to the home network, the mobile subscription may also connect to the Russian mobile network on the Finnish side of the border. Similarly, on the Russian side of the border, the mobile subscription may be connected to a home network or a visited network. A similar problem exists in other border regions 15, for example near the border between Finland and Sweden.

Unexpectedly, the switching of the network serving the mobile subscriber line causes significant problems for customers living or moving in the border area. The difference in the price of mobile use between home and roaming networks is very significant, so the accidental use of a mobile subscription through a roaming network can result in additional costs of up to EUR 20 hundreds. The customer can detect his mobile subscription on the display of the serving network, but in practice there are situations where the serving network does not have to be checked, for example, when driving a car or when answering a busy call.

The object of the invention is to provide a technical solution which can reduce the probability that a mobile subscriber is connected to a visited network in the service area of a home network.

The invention is based on providing a control function for a mobile subscriber interface for use in a border area, which directs to make home network searches more frequently than usual.

More specifically, the control method according to the invention is characterized in what is set forth in claim 1.

The subscriber identification unit according to the invention, in turn, is characterized by what is claimed in claim 14 and the computer program product is characterized by what is claimed in claim 23.

In one embodiment, the control function is implemented by a search period for home web searches.

The Home Network Search Period (HPLMN search period) is a parameter that informs the mobile station how often it must search for the home network 10 of its accessing subscriber when the subscriber is connected to the visited network. In G S M family systems, the home operator sets a search period on the SIM card and the mobile station performs home network searches under the control of the SIM card. The home operator thus selects the search period he considers appropriate within the range specified by the standard.

If the search period is very short, the mobile station consumes a considerable amount of power in the visited network, since the mobile station has to make a small search in the home network. Home network searches consume power and the mobile phone battery runs out quickly. Therefore, the value of the search period must be set so high that the use of the mobile station is not disturbed while in the visited network area.

On the other hand, if the search period is very long, the mobile station's power consumption is low at each visit, but there may be problems returning to the home network. If the visited network is able to serve the mobile subscriber within the service area of the home network, the mobile subscriber stays connected to the visited network until the next home network search.

In another embodiment, the control function is accomplished by forcing the mobile station 25 to perform a network connection operation at certain intervals. This can be done, for example, by modifying the Location Information File (LOCI) file stored on the SIM card. Otherwise, this embodiment will oppose applications that use the home page search period, so the same time intervals, transition conditions, and other rules may be used in the applications.

3

In the third embodiment, the longer Interval is accomplished by the home network paging search period and the Shorter Interval is accomplished by forcing the mobile station to perform the network connection function according to the second embodiment mentioned above.

In one embodiment, the arrival of the mobile subscriber line in the border area is identified by the connection to the visited network.

In another embodiment, the arrival of a mobile subscriber interface in the border area is identified by one or more cell identifiers of one or more mobile cells in radio communication with the mobile station.

In a third embodiment, the arrival of the mobile communication interface in the border area is identified based on the control received from the user.

In one embodiment, the location of the mobile communication interface in the border area is estimated based on one or more cell identifiers of one or more mobile communication cells in radio communication with the mobile communication device.

In another embodiment, the location of the mobile subscription in the border area is estimated based on the time elapsed after connecting to the visited network.

In a third embodiment, the location of the mobile subscriber line in the border area is estimated based on the number of cell exchanges that occurred after connecting to the visited network.

In a fourth embodiment, the location of the mobile interface in the border area is estimated by a combination of the embodiments described above, wherein the mobile interface is interpreted to have left the border area when all conditions selected from the above conditions are met.

In a fifth embodiment, the location of the mobile interface in the boundary 25 is estimated by a combination of the embodiments described above, such that the mobile interface is interpreted to have left the boundary when any of the above conditions is selected.

4

In a sixth embodiment, the location of the mobile communication interface in the border area is estimated based on control received from the user.

Embodiments of the invention provide the significant advantage that the search period for home network searches can be kept on average at a relatively low value in the border area and on average at a relatively high value in the visited network further from the border area. This significantly reduces the time the mobile subscriber is connected to the visited network in the home network service area, and thus reduces the likelihood of unnecessary costs. Nevertheless, the power consumption of the mobile station in the visited network can be considered reasonable, since in a typical usage, it is likely that most of the time spent in the visited network, the search period is more valuable.

In embodiments, the values of the search periods can be selected such that a lower value is at or near the minimum value specified by the standard and a higher value is a value higher than the standard search period value used conventionally.

15 The subscriber identity unit may be utilized to implement the embodiments.

A subscriber identity unit is a unit that can be connected to a mobile station for subscriber identification. The detection unit usually comprises an electronic circuit and can be fitted in a dedicated slot inside the mobile station. The subscriber identity module is commonly called a Subscriber Identification Module (SIM). The UMTS-20 network also refers to a USIM card, but in this publication the term SIM card also refers to such subscriber identity units corresponding to a SIM card used in newer networks.

Thus, it is possible to implement the embodiments using a SIM card. Such embodiments have the additional advantage that new elements or investments are not required in the mobile network.

In one embodiment, the application of the SIM card in the user terminal stores the cell IDs of the operators in the frontier zone in its own database on the SIM card, and uses this database to determine whether the terminal is located in the border area.

5

In one embodiment, both the cell IDs of the home network of the border area and the cell IDs of the visited operators are gradually stored on the SIM card. Thereafter, the SIM application can "" predict "the cells of the home network from which the switch to the cell of the visited network may take place. When in such an embodiment, the terminal arrives at such a cell in the 5 home network, the application sets the HPLMN search period to a short value, so that the connection remains more secure in the home network.

An interface is a technical and administrative entity, typically associated with a network ID, a subscriber ID, and subscriber information. When a subscription is said to be in a network or connected to a network, it is meant that the terminal using the subscription is radio-connected to the mobile communication network and, furthermore, the terminal is granted access to the telecommunications service provided by the mobile network. A similar situation is also meant in this document when referring to a terminal or mobile station being connected to a network. The term mobile subscriber interface refers to an interface that can be used by a mobile station and provides access to a mobile communication network.

In turn, when speaking about the location of a mobile subscription, it is meant where the mobile station using the mobile subscription is located. In a GSM network and similar networks using a SIM card or other similar subscriber identity unit, the location of the mobile subscriber unit is located against the location of the subscriber identity unit 20 associated with that mobile subscriber unit.

When the terminal finally moves across the border so far away that the home network is no longer included, the SIM application starts storing the cellular IDs of the visited networks in its database (e.g. 10 pcs). Once the terminal has advanced further from the boundary area, the SIM card application returns the HPLMN search period value to a longer value.

Similarly, when the terminal is again returning from the visited network area to the home network area and approaching the border area, the SIM application detects this because it "" knows "the cell IDs of the border area. Thus, the SIM application can now set HPLMN search period value is short, so the interface can switch from home network to network as soon as it is found.

6

According to one embodiment, the SIM card application returns the HPLMN search period value to normal when the terminal has moved from the border area to the inward home network.

According to another embodiment, the home page search period value, or HPLMN search 5 period value, is kept at a lower value, e.g., a minimum value, whenever the terminal is not interpreted to be "deep" in the visited network. Thus, in such an embodiment, the value of the search period is low whenever it is determined that the terminal is in a home network or in a border area. Keeping the search period small on the home network is not detrimental to power consumption, since the mobile station connected to the home network does not search 10 home networks.

According to a further embodiment, a function is implemented to ensure that the mobile station, when out of service in the home network, is using a particular preferred roaming network, at least for outgoing traffic.

According to another embodiment, a function is performed whereby a mobile station connected to a roaming network 15 other than the most popular roaming network periodically searches for a particular preferred roaming network. In this case, the likelihood of using the most popular roaming network can be improved even when outside the service area of the home network for incoming traffic.

The above and described embodiments can achieve a number of advantages.

With applications, mobile phone customers are highly likely to stay within the home network even near the national border whenever a reasonable connection to the home network is available.

For the subscriber, this entails clear benefits: 25 The customer does not have to make or receive calls, or send SMS messages at the roaming operator's network at high roaming charges if the home network has coverage in the border area. Especially in the customs queue, customers often spend many hours waiting to make phone calls while waiting to be sure they are on the home network's affordable network.

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When a customer returns home, he or she will have access to the home network as soon as possible, usually on a large foreign side. This allows home network rates and versatile services to be available most of the time.

Embodiments also offer benefits to the home network operator: 5 The home network operator receives all traffic revenue, not just roaming commission.

Even the large signal fluctuations in the boundary zone do not cause problems, as the SIM card application can hold the connection in the home network. This also avoids unnecessary signaling traffic when the home network HLR switches to and from the home network.

10 Embodiments can utilize existing SIM card technology without the need for additional network investment.

Embodiments are also automatically updated for cell IDs, so the SIM card is constantly updating its data without the active intervention of the operator.

The invention will now be described by way of example and with reference to the accompanying drawings.

Figure 1 shows a diagrammatic diagram of a mobile subscriber's movement from a home network to a visited network in one possible case.

Figure 2 shows a state transition diagram according to one embodiment.

FIG. 3 is a flowchart illustrating the interaction between a SIM card and a terminal in implementing a method according to one embodiment.

Figure 4 shows a cell exchange chart in one possible transition situation.

The embodiment of Figure 1 illustrates a case where a mobile subscriber moves from a Finnish home network (Elisa's network) to a roaming network on the Russian side. The figure shows a number of regions bearing an ELISA symbol representing Elisa mobile communication cells in the border region. Also shown in the figure are a plurality of shaded areas with the RUS-25 identifier representing the mobile network cells of the visited network in the border area. In addition, the figure shows the national boundary 1 and the route 2 of the mobile subscriber line using the arrows.

8

The following describes the management of the situation of Figure 1 according to one embodiment.

The SIM card application has stored the cell IDs of the border area cells in its database during its previous visit to the border area. The SIM application can '' predict '' the switch from Elisa's network to the Russian network using this database. Thus, when 5 terminals arrive at Elisa2, the SIM application sets the HPLMN search period short to ensure that the subscription remains on Elisa's network. As the terminal proceeds along path 2, the terminal moves across the border to Russia. The SIM card application then stores the cell IDs of the Russian network cells in the chain.

At some point, the connection to the home network is disconnected and the terminal connects to the visit-10 network. The SIM application will continue to store the Russian network cell IDs in its memory. When the terminal has stored a sufficient number of cell IDs, the SIM application stops storing the cell data and returns the HPLMN search period value to normal. This very likely corresponds to the situation where the terminal has moved farther from the border area. A sufficient number of cell identifiers may be a preselected number of, for example, 5 to 30. In the example, 10 cell IDs are stored even after the connection to the home network has been lost.

When the terminal returns to Finland along route 2 in the opposite direction, the SIM application detects that the mobile station is communicating with at least one cell whose cell ID is stored in the application database. Such a cell 20 may be, for example, cell RUS 1 in the pattern. In response to the observation, the SIM application sets the HPLMN search period as short as possible so that the interface can migrate to Elisa's network as soon as Elisa's network coverage begins. As the terminal progresses towards the home network, the subscription will transfer to Elisa's network. After the terminal has moved inland to Finland, the SIM application will reset the HPLMN search 25 period to normal

The above example can be varied in many ways.

In one variation, the storage of cell IDs is only started in response to the discovery that the mobile subscriber is connected or connected to a visited network.

In another variation, the storing of cell IDs is resumed in response to the discovery that 30 mobile subscriptions are connected or connected to a visited network.

9 In such embodiments, the home page lookup period is preferably kept at a lower value throughout the period when the mobile subscriber is within the home network service area. In this case, there is no need to identify the approach to the border area, as the home search period is already lower in value. Therefore, it is not necessary to store the cell IDs of the home network.

In one variant, cell ID storage is terminated on the basis that a connection to the home network is no longer available at a certain time.

In yet another variation, the storing of cell IDs is terminated in response to the fact that a connection to the home network is no longer established at a certain time and a certain number of 10 cell IDs are stored after connecting to the visited network.

In yet another variation of the preceding example, the storing of cell identifiers is terminated in response to either of the conditions of the preceding variation being met, i.e., no connection to the home network has been made at a certain time or a certain number of cell identifiers have been stored.

15 Different variations of the example can meet different customer needs if desired.

For GSM and 3G standards, the HPLMN (Home Public Land Mobile Network) search period can obtain values between 1-255. Each value means that the home network search is performed at specified intervals such that the length of the interval is obtained by multiplying the value of the HPLMN 20 search period by 6 minutes.

In the embodiments, at least two different values are used for the HPLMN search period, such that the smaller value is intended to be used when the mobile subscriber is located in the border area and the higher value is intended to be used when the mobile subscriber is located outside the border area. The lower value 25 can be selected, for example, from 1-10, preferably from 1-5. For enhanced effect, a lower value of 1, 2, or 3 is selected, which means that in the border area, the home network search is performed at the selected value every 6, 12, or 18 minutes. The lower value is preferably set to 1, at least for users for whom low power consumption in the border region is not a critical factor. Thus, the home network search is performed every 6 to 10 minutes, so that the connection can be connected to the visited network for only a few minutes at a time, where the home network would also be available.

A higher value for the HPLMN search period can be selected, for example, from 10 to 255, typically from 11 to 80. In the example, a higher value is set to 20, which 5 means that the home network is searched every 120 minutes in the visited network area.

Instead of the HPLMN search period, a separate timer can be used to set the time slot, which forces the mobile to perform a network connection function. In one embodiment, this is accomplished by changing the content of the LOCI (Location Information 10 Lile) on the SIM card at predetermined intervals in an appropriate manner. The LOCI file typically contains the last detected LAC (Location Area Code), MNC (Mobile Network Code) and MCC (Mobile Network Country Code). In addition, the LOCI file contains status information. The change in the embodiment involves changing the status information of the LOCI file to "not updated", in which case the mobile station must initiate a network connection-15 operation. Initially, the mobile station performs a home network search for the network connection function. This procedure can also be applied in the embodiment of Figure 3 below.

The forced network connection feature can also be used to select the most popular visitor operator in the visited network area. An application 20 may be implemented on the SIM card which acts in response to a connection request when the mobile station is connected to a visited network. A call request is here an attempt by a mobile station to start, for example, making a call or sending an SMS or multimedia message. In such a situation, the SIM application checks if the mobile station is connected to the most popular visited network. If the mobile station is connected to the most popular visited network, the connection is started normally.

If, on the other hand, the mobile station is not connected to the most popular roaming network, the SIM application directs the mobile station to display a menu asking the user to confirm whether he wants to continue connecting to the 30 roaming networks currently in use or to search for the most popular roaming network. If the user wishes to continue establishing the connection in the current network, the connection will continue normally. If, on the other hand, the user wants to search for the most popular network, the SIM card application will force the mobile station to perform the network switching function first and will only continue the connection after performing the network connection function. In this case, the connection is established according to the preference order stored in the SIM card application 5 through the first possible mobile network, i.e. primarily through the home network and secondarily through the most popular visited operator. The connection is established through the other visit operator only if neither of the previous networks is available. For example, in this embodiment, forced network connectivity may be implemented by modifying the contents of a LOCI file on the SIM card as described above.

One example of the use of the embodiment described above is where the home operator has a cooperation agreement with one particular visit operator. In this case, the use of this particular roaming operator will allow, for example, a better service package or more attractive pricing for the 15 customers in the roaming network. However, while in the roaming network, the mobile station may be disconnected from the co-operator's network and locked in another roaming network. You will not be able to leave that other network today unless you restart the phone or manually redirect the mobile to the partner network. Therefore, it would be advantageous for the user to be able to select the network of the cooperator unless the user is on the cooperator's network prior to making a call, sending 20 SMS messages or opening a data connection. In this case, the SIM application automatically puts the call to start, the sending of an SMS, or the opening of a data connection to hold state, and performs the above-described procedure for connecting to the network of the cooperating operator. After that, the call, SMS transmission or data connection is continued automatically. This results in a delay of about 30-45 seconds, but there may be quite a bit of money savings or Service Advantage. The operation is also easy for the user, as all he needs to do is acknowledge in the menu of the mobile display that he wants to establish a data connection through the network of the co-operator - everything else is automatic. For example, the menu might ask, '' Looking for a partner network? '' And 30 answers will only have to be YES or NO in the menu.

Searching for the most popular roaming network can also be performed periodically, for example, in the same way as searching for a home network in a border area is shown in embodiments.

12 For such a scheduled visit operator selection function, an application may be implemented on the SIM card which performs the network connection function at certain intervals when the mobile station is connected to the visited network. The network connection function may be implemented, for example, as described above, and the timing may be implemented, for example, by means of a time counter or the like described in connection with FIG. 3 below.

The SIM application may also be set up to detect a situation where the mobile station is outside the boundary area connected to the network of the most popular visit operator. In this situation, the network connection function may be omitted or performed at longer intervals. If, on the other hand, the mobile station is connected to another roaming network, the network switching operation may be performed at shorter intervals in a manner similar to that described in home application searches in the border area.

The timed visit operator selection function may be implemented as an alternative to function-15 which responds to a call set-up request. The timed function, which is responsive to the connection request, may also be active at the same time and programmed on the SIM card.

Fig. 2 shows an incident diagram n in accordance with one example. According to the figure, the mobile interface has a Home Network 201 for staying in a home network, a Boundary area 202 for staying in a border 20 area and a Visiting network 203 for staying in a roaming network. the mobile subscription is connected to a home network. In this case, the status does not change, so the mobile station continues in Home network 201.

211) The state transition 211 relates to the connection of a mobile subscriber from a home network to a visited network. In the embodiment illustrated by the example, the state transition period 211 sets the HPLMN search period to a lower value.

212) The state transition 212 is associated with the connection of the mobile subscriber from the visited network to the home network, wherein the HPLMN search period is set to normal value in the embodiment described in this example.

13 213) The state transition 213 implements the transition from state Boundary area 202 to state Visiting network 203, which is implemented when the transition condition is met. In the exemplary embodiment, the transition condition associated with state transition 213 is the expiration of a predetermined time. In the example, the predetermined time is calculated from the moment when the mobile station enters the boundary state 202, i.e. from the state transition 211 or 215. The state transition 213 is thus related to the situation where it can be deduced from the elapsed time (Timeout) that the home network can no longer have coverage in the location area of the m at k telecommunication interface. During the state transition 213, the HPLMN search period is set to normal.

214) The state transition 214 implements a transition from a state boundary 202 to a guest network 203. In the exemplary embodiment, the state condition of the state transition 214 is that the mobile station has experienced a predetermined number of handovers after the mobile station enters the state boundary 202. , whereby the calculated handovers indicate that the 15 home networks can no longer have coverage in the location area of the mobile subscription.

During state transition 214, the HPLMN lookup period is set to normal value.

215) The state transition 215 implements a transition from the state of the Visiting Network 203 to the state of the Frontier Area 202. In the exemplary embodiment, the transition condition is that the mobile station implements a transition in the visited network to a cell known to be in the border region 20. During the state transition 215, the HPLMN search period is set to a lower value.

216) The state transition 216 implements the preservation of the interface in the border region in a situation where Timeout is not realized and the number of handovers is not exceeded.

217) The state transition 217 performs handover monitoring in a situation where a new cell in the roaming network serving the mobile station is not identified as being in a border area.

218) The state transition 218 implements a migration directly from the visited network to the home network. This is the case, for example, when the connection returns to the home network when closed. A typical example is traveling by plane.

14

In addition to the state transitions described above, it is also possible to switch directly from the home network to the roaming network directly. This could be the case, for example, after a long flight.

FIG. 3 illustrates, in one embodiment, a flow chart of the interaction between a SIM card and a terminal 5 in a home network 311, a boundary 312, and a visited network 313, the location areas of which are illustrated by correspondingly numbered broken line boxes.

In block 301, the method execution is started.

Block 302 checks whether the interface is connected to the home network. If the interface 10 is connected to the home network, it returns to block 302. If the connection is not connected to the home network, then proceeds to block 303.

In block 303, the HPLMN Search Period is set to a lower value. In addition, the time counter and the cell count counter are reset and the time and cell count count is started. At the same time, cell IDs are also stored in the Border Region Database. After this, j is returned to block 304.

Block 304 checks whether a connection to the home network is available. If access to the home network is made, proceed to block 310. If the home network is unavailable, then proceed to block 305.

Block 305 checks whether the time counter value has reached a threshold value. If the value of the time counter 20 has reached a threshold, proceed to block 307. If the value of the time counter has not reached a threshold, proceed to block 306.

Block 306 checks whether the handover counter value has reached a threshold value. If the value of the handover counter has reached a threshold, proceed to block 307. If the value of the handover counter has not reached a threshold, proceed to block 304.

25 In block 307, the HPLMN Search Period is set to a higher value. The time and cell handover counting can be stopped and cell IDs stored in the Border Database can be interrupted. After this, block 308 is proceeded.

15

In block 308, cell changes are monitored and block 309 is always invoked in connection with the cell change.

In block 309, a check is made to determine whether the cell ID of the new serving cell is in the Boundary Database. If the cell ID of the new cell is found in the Boundary Database, 5 proceeds to block 303. If the cell ID of the new cell is not found in the Boundary Database, return to block 308.

In block 310, the HPLMN Search Period is set to a higher value. The time and cell handover counting can be stopped and cell IDs stored in the Border Database can be interrupted. After this, block 302 is proceeded.

Figure 4 shows cells in a cellular network with arrows and arrows of cells in the mobile station when switching from one cell to another in a home network 4 to a visiting network 6. In the figure, in an embodiment of Figure 4, the SIM card application actively examines cell changes and stores data related to cell exchange events as a "chain". its memory. At some point, the cells in the home network run out and the cell exchanges in the visited network cells continue. By storing the cell changes in the area represented by the dotted line on the SIM card, the cell IDs of all the cells in the border area are gradually collected in the Border Database, and the SIM application learns how to detect when the border area is approaching.

In the embodiment of Figure 4, each SIM card independently collects data as shown in Figure 4, thereby gradually learning the boundary or boundary regions to be visited.

A similar function can also be implemented in that all the cards having the SIM application of the operator regularly transmit the detected area information to a centralized database of the operator. From such a centralized database, a border cell list can then be distributed to all subscriptions with this SIM application. In this embodiment, the interface can utilize the cross-border information obtained by other interfaces even before it has itself visited that border.

An embodiment using a centralized database also allows different boundaries to be defined for different subscriptions or types of subscriptions, if necessary. The boundary 16 definitions can be made in the mobile network and delivered wirelessly to the mobile stations.

Also, in embodiments using a centralized database, border sizes and / or contents (cell lists) may be different between different interfaces. The selection criteria may be, for example, a particular subscription, a group of subscriptions, or the type of terminal equipment used by the subscription. The user can also be given the opportunity to define the size of the boundary itself and / or its contents (cell list). This can be accomplished, for example, by providing a configuration function via the SIM Tool Kit or, for example, via the Internet interface. Similarly, the user-defined boundary can be implemented in conjunction with the boundary database stored on the SIM-10 card. Correspondingly, a forced control function can also be programmed into the SIM card application, which allows the user to determine the subscription to the boundary mode himself.

It is therefore clear from the above examples that numerous solutions other than those described above can be implemented within the scope of the invention. Thus, the invention is not intended to be limited to the above examples, but patent protection should be considered in its entirety in the appended claims.

Claims (25)

A method for setting the length of a time slot between successive home network pagings of a mobile subscriber, the method of setting a first value for being within range of a roaming network (6) and a second value less than a first value for being in a border area (5) of a roaming network. maintaining, locally, in the system using the mobile communication interface, a border area database for collecting cell identifiers of cells of the mobile network located in the border region (5). Method according to claim 1, characterized in that the length of time slot 10 is set by the home page search period by setting (307) a first value for the home network search period to be within range of the roaming network (6) and setting (303) a second value in the border area (5) between the home network. A method according to claim 1, characterized in that the second value of the length of at least 15 slots is set to direct the mobile subscriber to perform a network connection function at certain intervals. Method according to Claim 1, characterized in that the border area database is maintained in the subscriber identity unit. Method according to claim 1, characterized in that the border area database is maintained in the mobile station. A method according to any one of claims 1 to 5, characterized in that entry into the boundary area (5) is detected (309) on the basis of the cell identifier of the cell of the mobile network serving the mobile station. Method according to one of Claims 1 to 5, characterized in that 25 mobile subscriptions are interpreted (302) as having arrived at the boundary area (5) when the mobile subscriber connects from the home network (4) to the visited network (6). A method according to claims 1-7, characterized in that the mobile communication interface is interpreted (305) as having left the border area (5) after a predetermined time has elapsed since entering the border area (5). A method according to any one of claims 1 to 7, characterized in that the mobile station is interpreted (306) as having left the boundary area (5) when, after entering the boundary area (5), the mobile station has made a predetermined number of cell exchanges and. Method according to one of Claims 1 to 7, characterized in that 5 mobile subscriptions are interpreted (304) as having left the boundary area (5) when the mobile subscriber is found to be connected to the home network (4). Method according to one of Claims 1 to 10, characterized in that the boundary area is defined on the basis of input received from the user of the mobile communication interface. Method according to one of Claims 1 to 10, characterized in that the boundary area is defined locally by the operation of a mobile station using a mobile communication interface. Method according to one of Claims 1 to 10, characterized in that the boundary area is defined in the mobile communication network and the configuration information is transmitted wirelessly from the mobile communication network to the mobile station. 14. A subscriber identity unit for a mobile station adapted to direct a mobile station to perform home network paging at first intervals, characterized in that the subscriber identity unit is adapted to direct the mobile station to perform 20 home network pagings optionally, at shorter intervals, the subscriber identity unit comprising for storing cell identifiers, and rules are made in the subscriber identity unit for making a selection between the first and second intervals. The subscriber authentication unit according to claim 14, characterized in that the subscriber authentication unit is adapted to perform the control of the first intervals by means of the home network paging search period and the first value of the home network paging search period is stored in the subscriber identification unit. 16. The subscriber identity unit according to claim 15, characterized in that, in addition to the first value, the second value less than the first value is stored in the home page lookup period and rules for selecting the first value and the second value as the current home page lookup period value. The subscriber identity unit according to claim 14 or 15, characterized in that, for the implementation of the second, shorter interval than the first, the subscriber identity unit is arranged to force the mobile station to perform the network connection function at other intervals. A subscriber identity unit according to any one of claims 14 to 17, characterized in that it comprises the functionality for receiving control from the user that influences the selection between the first and second intervals. A subscriber identity unit according to any one of claims 14 to 18, characterized in that it is adapted to control the mobile station according to at least one of claims 1 to 13. A subscriber identity unit according to any one of claims 14 to 19, characterized in that it is adapted to perform a visit operator selection function in response to a user's attempt to open a communication connection or to transmit communication through the visited operator's network. A subscriber authentication unit according to claim 20, characterized in that information on the most popular visit operator is stored in the subscriber identification unit and the visit operator selection function is adapted to operate such that the mobile station is connected to a visit network other than the to receive the input, - based on the received input, the subscriber identity unit instructs the mobile station to either 1) continue directly transmitting or opening a communication link, or 2) first retrieve the home network and / or preferred visited network and resume sending or opening the communication link. A subscriber identity unit according to any one of claims 14 to 21, characterized in that it is adapted to carry out a scheduled visit operator 5 selection function when the mobile station is connected to a visit network of a visit operator other than the most popular visit operator. A computer program product for controlling a network connection of a mobile subscriber, adapted to direct a mobile station to use a first home network paging control function for being within the visited network (6) and a second 10 home network paging control function for performing more often than the first function, characterized in that the computer program product is adapted to control the mobile subscriber system to locally maintain 15 border area databases in the mobile subscriber system and to collect cell identifiers of cellular network cells located in the border area (5). A computer program product according to claim 23, characterized in that it is configured to direct the mobile station to use a first value for being within range of the visited network (6) and less than a second value less than a first value for being within the boundary (5) of the visited network. Computer program product according to claim 23, characterized in that it is adapted to implement the method according to one of claims 1 to 13.