Recovering group data between mobile systems

GROUP DATA RECOVERY BETWEEN MOBILE SYSTEMS

Fundamentals of the invention

The invention relates to a method for retrieving group data between mobile systems which incorporates at least one first mobile system which comprises a first database, at least a second mobile system which comprises a second mobile system. database and service area, mobile systems incorporating mobile stations as subscribers, the process comprising the steps of maintaining group data in said first database of said first mobile system and maintaining group data in said second database of the second mobile system.

The invention relates to a plurality of mobile systems, in particular mobile systems, comprising control centers, one or more databases, base stations and radiotelephones, the mobile systems having a cellular structure and each cell having at least one base station which communicates via one or more radio links with at least one mobile station. The radio link may be established through channels, one or more of which are typically used for signaling and the remainder for traffic.

WO 96/29838 describes an example of a mobile system and the updating of its subscriber data.

The process of the invention is intended for use specifically in so-called mobile trunking systems, which are typically corporate networks or private radio link networks used by the authorities, and all channels on these networks are assigned to them. one or more companies or organizations of official authorities. In these networks, subscribers have, in addition to their own subscriber numbers, group numbers, which indicate to which group the group calls belong to that subscriber, whereby calls, particularly group calls, to which intended for all subscribers of said group, may be switched to said group of subscribers.

The invention is applicable to mobile systems with both digital and analog radio paths. Analog mobile systems are described, for example, in the British Department of Trade and Industry publications MPT 1327, A Signaling Standard for Trunked Private Land Mobile Radio Systems. -Junction-linked Terrestrial Private Furniture), January 1988, revised and reissued in November 1991, edited by the Radiocommunications Agency and MPT 1343, Performance Specification, January 1988, revised and reissued September 1991, edited by Radiocommunications Agency.

A group call is one of the main functions in a private radio-mobile network. A group call is used, among other things, in various operations involving multiple participants, especially when the whole group should be aware at all times of how things are developing. A group call is a call in which all participants can have their turn to talk and to listen to each other. In group calls, the entire group is called by a call number. A single radio unit, for example a mobile radio station or a radiotelephone, i.e. a subscriber station, may belong to a plurality of groups which are programmed into the mobile station. Programming can be performed permanently, but can also be modified by the user or even by the system. Each mobile system may keep a base file for each of the group numbers on base stations. A group call may cover one, several or all base stations of the mobile switching service center area and a plurality of mobile switching centers, or a group call may be established within the mobile switching area. service of various mobile systems.

When establishing a group call, it is assigned a traffic channel on all group-related base stations and each base station transmits a group call request, which comprises the group number and channel information. of assigned traffic. If the mobile station identifies the group number included in the group call request, it transfers it to the traffic channel indicated by the group call request. Thus, the mobile station, which is registered in the predetermined operating area for the group, is in principle always available for a group call.

In connection with cellular radio networks, it is known that the group data of the radiotelephones registered in said mobile system are stored in the mobile system database with junctions, for example in the switching center or in the visitor location register or in the resident location record.

Group data (group profile) contains data informing subscribers of that group or some of the subscribers of the group of available or activated services, for example supplementary services. The group profile may also contain definition of the importance, that is, of the priority of said group or its subset. In addition, the group profile may contain information about which subscribers belong to said group, that is, a list, including the identifiers of those subscribers, who are allowed to participate in communication within said group, for example in a group call , in the service area of ​​said mobile system, in their specific location areas (Location Area) or at their specific base stations.

This group profile is stored, for example, in volatile Random Access Memory (RAM), from which data disappears when, for example, the power supply to the database is switched off and at regular intervals, on nonvolatile memory media, for example on a hard disk, on which data is permanently kept. When the RAM database sometimes starts up again, the group profile stored in volatile memory disappears. Only group data is stored in nonvolatile memory, for example on the hard disk.

The disappearance of database group data causes a serious problem in the grouping of a plurality of mobile systems, since if a given group call extends to service areas of various mobile systems, group call group data is stored in the databases of all said various mobile systems. Therefore, if the database of any of the mobile systems must be shut down and since the database of the shut down system cannot continuously update changes that have taken place in the group's group profile, such data may in the meantime change. themselves in the databases of other mobile systems, but remain unchanged in the offline database. As a result, the group data contained in the database of the different mobile systems becomes different, on the one hand on the offline database and on the other on the normally functioning databases.

This difference between database group data may give rise to a situation where a particular mobile station is allowed to join a group call in a first mobile system, but in a second mobile system said mobile station is not. authorized to join the same group call, since the database of that group was not kept up to date in said mobile system or in its database.

US 5564071 describes an example of a communication system through link joints and the attributes of the communication update unit contained therein.

According to the prior art, it is possible to try to consistently maintain the contents of the databases of various mobile systems by using so-called retrieval.

The retrieval process uses a normal sequence between mobile system networks, or the like, whereby sequential on-off requests sent by subscriber terminals operating on the network are processed, and requests are addressed to a group on another network. . In the Trans-European Trunked Radio Systems (TETRA) system, this sequence is an Additional Network Feature (ANFISIMM) sequence. ). This sequence is described in the TETRA specification ETS 300 3923-5, Part 3: Inter-working basic operations; Part 3-5: Additional Network Feature Inter-System Interface for Mobility Management (ANF-ISIMM), ETSI, March 1997, 167 pages.

A normal group profile update sequence begins when a subscriber terminal sends a connection request to a mobile system and said mobile system is not the group's home mobile system. In the TETRA mobile system, the mobile home system is a resident Switching and Management Infrastructure (SwMI) and correspondingly the visited mobile system is a visited SwMI. Therefore, the visited mobile system communicates the connection request to the group's home mobile system, which stores the connection request and responds to the visited mobile system by sending the group profile. The visited mobile system stores the link and other group data in its database. The group data is kept stored in the visited mobile system database as long as there is at least one valid connection request for said group.

When the visited mobile system receives a terminal connection request from the subscriber terminal, any of the following procedures may be applied:

1) If several subscriber terminals send call requests to the same group of a second mobile system in the same visited mobile system, the visited mobile system sends the call request to the home mobile system only once when it receives the first connection request. The mobile group call residence system is, for example, the system in whose database the group profile of said group is stored.

2) The procedure described above can be supplemented by a so-called important user definition: important users can be defined within the group and the connection request sent by them is always communicated to the group's home mobile communication system. Thus, important users are users who are given priority.

3) Alternatively, the visited mobile system always sends the connection request to the home mobile system when it receives a connection request from a subscriber terminal.

According to a principle corresponding to the above, the visited mobile system communicates one or more disconnection requests received from radio subscribers to the home mobile system. Disconnection requests are reported one by each group or by a significant user or subscriber. Thus the shutdown data is deleted from the database in the home mobile system and the connection data and other group data are correspondingly deleted from the visited mobile system databases.

If the visited mobile system sends the connection requests to the home mobile system only once, when it receives the first connection request, the connection request is only sent to the home mobile system after it has been received by the last mobile device. subscriber connected to said visited mobile system group. All data of said group are then deleted from the visited mobile system database. In addition, for that subscriber, said subscriber's connection data is deleted from the group's and subscriber's home mobile system database.

A disconnect request received from an important user always deletes the connection data for said subscriber from both databases. In addition, the above rule applies to a disconnect request received from an important user, if said user / subscriber was the last subscriber of the group.

If the visited mobile system always sends a connection request to the home mobile system, when it receives a connection request from a subscriber terminal, the disconnection request is also always sent. If the disconnect request arrives from the last subscriber connected to said group in the visited mobile system, all data from said group is deleted from the visited mobile system database. In addition, for that subscriber, the connection data of said subscriber is deleted from the subscriber's residence system and group's database.

Figure 1 illustrates a visited SwMI / MM structure of a radio subscriber 101, a visited visited mobile system SwMM / FE3 - SwMM / FE3 102 a Home SwMM / FE2 103 mobile home system. The figure shows the parameters transmitted in each of the messages or signals. GTSI, that is, Group Tetra Subscriber Identity is a group identifier, ITSI is a radio subscriber identifier. The ITSI identifier does not need to be transmitted if the first connection request and the last group disconnection request are only communicated to the mobile home system, or in other words, if important subscribers are not favored or prioritized and not communicated. all connection requests.

In Figure 1, mobile station 101 sends a connection request 105 whereby the mobile station expresses its desire to be connected to a group within the service area of ​​the visited mobile system in question. In response to the above request, the visited mobile system checks in its database whether the visited mobile system is prepared to support the use of said group. If so, the visited mobile system follows the connection request 106 to the FE2 group mobile home system 103. The mobile home system checks its database to verify that it is prepared to support the use of the mobile device. said mobile system group visited for said subscriber. If so, the mobile home system transmits the data of said group 107 to the visited mobile system, which sends an acknowledgment of receipt 108. After receiving it, the mobile home system 109 sends an acknowledgment of receipt to the visited mobile system 102 in which it reports that the complete sequence was successful. The visited mobile system further alerts 110 to mobile station 101. The sequence described above is an example of the prior art procedure in which the first subscriber / mobile station wishes to be connected to the group in the service area of ​​said mobile system in a situation where the link is viable.

Brief Description of the Invention

The object of the invention is to provide a process and equipment that implements the process in order to solve the above problems.

This is achieved by a process characterized by that described in claim 1.

The invention also relates to a device for retrieving group data between mobile systems, where there is at least one first mobile system, which comprises a first database, where group data is kept for at least one second. mobile system, comprising a second database, wherein said group data is kept and wherein mobile stations exist.

The device according to the invention for retrieving group data between mobile systems is characterized by that described in claim 14.

The invention is based on the idea that subscriber group data retrieval can be performed in such a way that a system generated virtual connection request is sent to each visiting subscriber of a visited mobile system or visited node. for the mobile residence system or the residence node, so that group data and possibly subscriber location and subscriber data are updated in all databases, according to the normal binding sequence.

The idea of ​​the invention is the retrieval of subscriber call group data between interconnected mobile systems by sending a connection request, similar to a normal connection request, generated by the mobile system to the mobile home system of each group. visited, for each of the groups of another mobile system in use in the visited mobile system, whereby the group data is updated in the mobile systems according to the normal connection sequence.

The invention also relates to an idea according to which the home mobile system keeps during retrieval a record about which connection data is processed in retrieval. When the home mobile system receives a notification from the visited mobile system, reporting that the role of the visited mobile system is over, the home mobile system scrolls through its database and checks by comparison whether there is connection data for the visited mobile system. , which have been sued because the visited mobile system has not notified about it. 0 mobile home system transmits said connection data to the visited mobile system by means of a virtual connection request in accordance with the normal connection sequence. Virtual connection requests include the age of said connection data. The visited mobile system accepts the connection request received from the home mobile system if the visited mobile system has not stored subsequent corresponding connection data. 0 The visited mobile system may also reject the connection request for any other reason, for example if the visited mobile system does not support the group in question.

Alternatively, the home mobile system does not keep a record of the connection data transmitted by the visited mobile system, but retrieves from its database all connection data related to the visited mobile system and transmits it to said visited mobile system. . An advantage of this procedure is its simplicity, as no record keeping is required. However, in this case the resource consumption is not optimal.

The invention relates to a method and a device for retrieving group call group data, i.e. a group profile, of visiting subscribers between mobile systems and / or mobile network databases.

The invention is used to detect and correct inconsistencies in group profiles in interconnected TETRA mobile networks.

An advantage of this type of process according to the invention is that it solves the problems of prior art solutions.

The method and device according to the invention also have the advantage that the process utilizes normal group data processing sequences. This simplifies the implementation of recovery and improves reliability.

The invention also alleviates the loading problems of mobile systems since, by means of the invention, the recovery load is automatically adjusted according to the loading conditions of each mobile system or the connections between mobile systems, if any. retrieval is performed according to the most preferred embodiment, i.e. synchronization of the transmission with the use of acknowledgments.

In addition, the invention has the advantage that no data needs to be deleted from databases unless there is more accurate data than previously stored data in the database.

The invention also has an advantage in that the process of the invention allows initiation in a variety of ways, for example periodically, by user order or as a result of a detected or assumed error.

Another advantage of the invention is that it is suitable for background processing in the mobile system.

The invention further has an advantage in that it is not subject to pulses from subscriber terminals. Therefore it is also possible to recover, with the method according to the invention, those cases in which no impulse is received from the subscriber.

An advantage of the invention is also that it makes it possible to adjust the recovery speed and the load according to other loads in mobile systems.

The invention has an advantage that the speed of recovery implemented therefrom does not depend on a random moment of pulse arrival.

The invention also has an advantage in that it does not consume any radio resources.

The invention has an advantage that, by synchronizing the transmission of a new connection request with acknowledgment of receipt of the preceding request, the recovery load can be adjusted according to the total load when capacity is available for it. .

The invention has an advantage that an additional load caused by it is minimal when some part of the system is charged for any other reason.

The invention has the advantage that when it functions accordingly, a mobile system node does not carry another node or link in a way that cannot be managed by them.

Brief Description of Drawings

The invention will be described in more detail below in connection with preferred embodiments and with reference to the accompanying drawings in which

Figure 1 illustrates a diagram of a message according to the prior art process,

Figure 2 is a flow chart of the process operation according to the invention,

Figure 3 is a block diagram of a device according to the invention.

Detailed Description of the Invention

Recovery

Figure 2 shows a flow chart of the process operation of the invention. Correspondingly, Figure 3 shows a device whereby the process of Figure 2 can be implemented. 0 The block diagram of Figure 3 illustrates a device for retrieving GD group data between mobile systems Sl, S2, S3, wherein there is at least one first mobile system Sl, comprising a first database DB1 and a service area. SAI, at least a second mobile system S2, comprising a second DB2 database and a service area SA2 and in which there are mobile stations MSI, MS2. Mobile systems are interconnected via T telecommunication connections through the interface between ISI systems between

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<td>described</td><td>at</td><td>ETSI specification, ETS</td><td> 300</td><td> 392-3-5,</td><td>above</td>

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typically one or more radio units, a BS base station may serve as such unit.

Recovery of group data can be initiated on the initiative, either from the group's mobile home system or from the visited mobile system. Recovery may be initiated, for example, periodically, at the user's request or as a result of a detected or suspected error. Recovery may involve one or more visited mobile systems and one or more mobile home systems. Recovery may be performed simultaneously or successively for a plurality of mobile systems.

If recovery is established at the initiative of the mobile home system, it transmits a recovery start request to all visited mobile systems with which recovery is desired. Upon receiving such a request for establishment, the visited mobile systems initiate the retrieval of the data of said groups of said mobile home system which exist in their databases.

If the recovery is initiated at the initiative of the visited mobile system, it transmits a start of recovery notification to the home mobile systems with which it wishes to recover and initiates the recovery of the data of said mobile system groups existing in the your database.

If desired, group data retrieval may be combined with location and subscriber data retrieval, for example by retrieving subscriber data, specifically group data related to each subscriber, immediately or for example. , by retrieving group data after the location and subscriber data of all subscribers has been recovered.

If desired, establishment messages can be ensured, for example with a transmission protocol, which includes, if necessary, acknowledgments of reception and retransmission of the establishment message.

The retrieval may be such that the visited mobile system scrolls through its database and transmits, in its normal sequence, one or more virtual connection requests per group to the mobile home system of each second. network group that are in your database participating in the recovery.

Virtual connection requests contain the age of said connection data. The mobile home system accepts the connection request from the visited mobile system if the mobile home system has not stored corresponding subsequent disconnect data. The home mobile system then updates 308 the corresponding connection data contained in its database and transmits the data from that group 309 to the visited mobile system. The mobile home system may also reject the connection request for any other reason, for example if said subscriber is not allowed to join the group. The mobile home system also checks, in the normal sequence, whether the subscriber is registered with said visited mobile system, according to the information contained in the mobile home system. If this is not the case, the mobile home system initiates a normal location correction sequence and similar data.

Link data and other group-related data (group profile) are updated in both the visited mobile system and the visited mobile system according to the normal on / off sequence. In addition, the visited mobile system always checks whether the subscriber who is connected to the group also has the valid registration for said visited mobile system. If the register does not exist, the connection data is deleted in accordance with the principle of the normal on / off sequence.

Mobile systems do not necessarily store any disconnect data from any group call in their databases after the normal disconnect sequence is complete.

visited mobile system transmits virtual connection requests to home mobile systems according to the same principles as normal connection requests.

If the normal procedure is for the visited mobile system to transmit the connection request to the home mobile system only once after receiving the first connection request for said group, then only one group connection virtual request is transmitted on retrieval. .

If the above procedure is supplemented with a so-called important user definition, a virtual connection request is transmitted upon retrieval by each important subscriber, provided that the group call involves one or more important or priority subscribers.

If the visited mobile system normally transmits a connection request to the home mobile system, each time it receives the connection request from the subscriber's terminal, a virtual connection request is transmitted on the retrieval by each subscriber connected to the group.

If the normal sequence is optimized so that the home mobile system does not transmit the group profile to the visited mobile system each time it receives a connection request from the visited mobile system, the retrieval sequence according to the invention it must be supplemented in such a way that the transmission of the group profile is ensured upon recovery. This can be performed on recovery in any of the following ways,

a) in the connecting virtual message, the visited mobile system requests at least once for each relevant group that the home mobile system transmits the group profile to said visited mobile system.

This solution requires a field for this purpose in the ISI call message between different TETRA mobile systems, or

(b) the mobile home system ensures the transmission of the group profile at least once for each relevant group to each relevant visited mobile system.

During the recovery, the home mobile system keeps track of which connection data is processed in the recovery. When the home mobile system receives a notification from the visited mobile system that the role of the visited mobile system has ended (see recovery termination), it scrolls through its database and checks, by comparison, whether the database contains connection data that relates to the visited mobile system and remains unprocessed, as the visited mobile system has not notified you of this. The home mobile system generates 310 second call requests and transmits 311 this call virtual data to the visited mobile system in call virtual requests according to the normal call sequence. Virtual requests contain the age of said data. The visited mobile system accepts the connection request, which comes from the home mobile system, if the visited mobile system has no subsequent corresponding disconnect data stored. The visited mobile system then updates 312 said data group in its database, from which the home mobile system is notified. The visited mobile system may reject the connection request also for other reasons, for example if it is not possible or allowed to form the group in said visited mobile system.

Alternatively, the home mobile system does not keep a record of the connection data transmitted by the visited mobile system, but retrieves from its database all connection data related to said visited mobile system, generates 310 second virtual connection requests and transmits them 311 for the visited mobile system. Simplicity is an advantage of this procedure as no record keeping is required. On the other hand, in this case the resource consumption is not optimal.

If desired, retrieval of group data may be combined with retrieval of location and subscriber data, for example by retrieving subscriber data, specifically group data related to each subscriber, as soon as the data subscriber location information and subscriber data have been recovered or, for example, by retrieving group data, after the location and subscriber data of all subscribers have been retrieved.

If desired, group data retrieval between the subscriber terminal and mobile systems may be combined with group data retrieval between mobile systems. The order of execution of these recovery operations may be selected in a desired manner.

If desired, the arrival of messages sent in a sequence may be ensured, for example with a transmission protocol, which comprises a retransmission of the message, if necessary.

The unsolicited portion of the visited mobile system ends for each home mobile system when it detects that it has retrieved data from all groups in said network. The visited mobile system transmits a notification to the home mobile system of each calling group formed in the termination coverage area of ​​its paper. The unsolicited portion of the visited mobile system ends completely when all home mobile system group calls are processed.

The home mobile system processes the connection data for each of the visited mobile systems that have been left unprocessed in the visited mobile part when it receives a notification of the role termination of said visited mobile system. The retrieval ends for said visited mobile system when the connection data is processed with said visited mobile system.

Recovery terminates on the home mobile system after it has received a termination notification from all visited mobile systems with which the recovery was performed and after the home mobile system has processed the unprocessed connection data present in your home. data base. If desired, the mobile home system may also notify participating mobile systems visited of the termination of the recovery. This data may be used, for example, for user information.

In the process according to the invention, the GD group data is kept 302 in the first database DB1 of the first mobile system Sl and additionally the GD group data is kept 303 in the second DB2 database of the second mobile system S2. In this case, as described in the above part of the description in connection with prior art problems, the problem is how to keep the group data in the DBl, DB2 databases unchanged and consistent with one another.

In the process of the invention this problem is solved such that a recovery request 304 is made for the recovery of GD group data.

The second mobile system S2 generates a virtual connection request 306 for the first database DB1 and transmits that request 307 to the first database DB1 of the first mobile system Sl.

In response to the virtual connection request, the GD group data from the first database DB1 is updated 308.

According to one embodiment of the invention, the first mobile system SL executes the above connection request by transmitting a recovery set-up message to all other mobile systems S2, S3, with which recovery is desired. and in response to this establishment message the other mobile systems S2, S3 start recovering their group data.

Alternatively, the second mobile system S2 executes the recovery request by sending a recovery start establishment notification to the first mobile system Sl, with which it wishes to perform group data recovery. In response to notification of the recovery recovery being performed, the second mobile system S2 initiates group data (GD) recovery in the second DB2 database.

The invention also relates to an idea, that the home mobile system maintains during recovery a record of which connection data is processed in the recovery. When the home mobile system receives a notification from the visited mobile system about the termination of the mobile system's role, it scrolls through its database and checks whether the database has connection data relating to said visited mobile system and remain unprocessed, as the visited mobile system did not notify them. 0 home mobile system generates 310 and transmits 311 said connection data to the visited mobile system in a virtual connection request according to the normal connection sequence.

Alternatively, the home mobile system does not keep a record of the connection data transmitted by the visited mobile system, but retrieves from its database all connection data related to the visited mobile system and transmits it to said visited mobile system. . Simplicity is an advantage of this procedure as no record keeping is required. On the other hand, in this case the resource consumption is not optimal.

In the process of the invention, in addition to retrieving GD group data, MSI subscriber-specific location data and subscriber data entered into the group specified in said first DB1 and second DB2 databases can be retrieved.

In the process according to the invention, the arrival of the recovery requests and said virtual connection requests is such that the recovery requests and the virtual connection requests are, if necessary, relayed.

Furthermore, according to the invention, the virtual binding request contains information about the age of the binding data. In response to information about the age of the connection data contained in the first virtual connection request, the first mobile SI system compares this information with the ages of possible connection data stored in the first mobile SI system and if the age of the connection request is less than the ages of the connection data previously stored in the first mobile system Sl, the first mobile system Sl accepts the virtual connection request transmitted from the second mobile system S2, that virtual connection request from which the GD group data of said GC group call is updated in the first database DB1.

Whereas, if the age of the connection request is higher than the ages of the disconnection data previously stored in the first mobile system Sl, the first mobile system Sl rejects the virtual connection request transmitted from the second mobile system S2.

If said disconnection and connection request data are the same age, the connection request may be accepted or rejected. This choice can be made to involve all related cases when implementing the mobile system.

Correspondingly, the second mobile system S2 processes the age of the second virtual connection request transmitted by the first mobile system Sl.

Figure 3 is a block diagram of a device according to the invention. In the device of Figure 3 there is a group of mobile systems Sl, S2, S3, in which there is at least a first mobile system Sl, comprising a first database DB1, where the group data GD is kept for at least one second. mobile system S2, which comprises a second database, where GD group data is kept and in which there are mobile stations MSI, MS2, of which at least some communicate within the group call established in service area SA2 of at least said second mobile system S2.

The mobile group may also include a third mobile system S3 in which a group call GC2 is maintained. Such a group call may be a second group call or a subset of the group call held in the service area of ​​the second mobile system S2, which group call is described in more detail herein.

In the device according to the invention, the second mobile system S2 comprises generating means GM2 for generating a virtual connection request for the first database DB1 and for transmitting the above virtual connection request to the first database DB1 of the first mobile system SL, whereby the first database DB1 is arranged to update the GD group data in the first database DB1 in response to that virtual connection request.

In the device according to the invention, the first mobile system SL comprises GM1 generating means for generating a virtual connection request for the second DB2 database and for transmitting the above virtual connection request to the second DB2 database. second mobile system S2, so the second DB2 database is prepared to update GD group data in the second DB2 database in response to that virtual connection request.

In the process of the invention, the arrival of messages may be ensured, for example, with a transmission protocol which, if necessary, comprises the retransmission of a termination message. For example, acknowledgment messages may be used, which give the sender an indication that the receiver has received the transmitted message.

If desired, the retrieval of group data may be combined, for example, with retrieval of location and subscriber data by retrieving subscriber-specific group data for each subscriber as soon as said location and subscriber data have been recovered or, for example, by retrieving group data, after the location and subscriber data of all subscribers have been recovered.

Recovery speed and recovery load can be automatically adjusted according to the load factor of both the visited database and the home database, such that connection requests are transmitted one by one with for the purpose that the network does not send any new virtual connection requests until the previous one has been processed on both networks. Thus, the network will not start processing the new virtual connection request until it has received an acknowledgment for the previous virtual connection request from the other network. In the event that the network does not receive an acknowledgment of receipt from the other network, continuity of a sequence may be ensured such that the network will continue to recover for a certain period of time if the acknowledgment of receipt is not received.

If desired, synchronization may be restricted to the transmission of only one new message: the network may process the new virtual connection request even before receiving the acknowledgment for the previous request and therefore the new message may be transmitted more quickly.

The process of the invention may be supplemented with decision priorities between virtual binding requests and other transactions, such as normal binding requests.

Alternatively, speed and load may be adjusted by, for example, pausing between the transmission of virtual connection requests.

If desired, the mobile home system may notify only the visited mobile systems participating in the termination request. This information can be used, for example, to warn users that both group data and even subscriber data and subscriber location data have been retrieved for a specific subscriber, mobile system, database or group call. .

If desired, the arrival of the messages to be transmitted in the retrieval sequence may be ensured, for example, with a transmission protocol comprising, if necessary, retransmission of the messages. Ensuring the arrival of messages is an advantageous procedure as it increases reliability.

It is an advantageous way to combine group data retrieval with subscriber and location data retrieval to retrieve subscriber-specific group data for each subscriber as soon as location data and subscriber data have been recovered as it is easier to handle an error where conflicting location data is detected on mobile home systems in connection with group data recovery. Therefore, the error can be corrected by restarting a subscriber-specific retrieval sequence from retrieving the location data and the sequence corrects both the location data and the group data.

Synchronizing the transmission of virtual connection requests with the acknowledgment of receipt from mobile home systems is a good way to implement it, as through it the recovery speed and recovery load can be automatically adjusted according to the factor. both visited mobile systems and mobile home systems. This process is also simple to implement.

It is apparent to those skilled in the art that the basic idea of ​​the invention may be implemented in various ways as technology advances. Thus the invention and its embodiments are not limited to the above examples but may vary within the scope of the appended claims.