MXPA00000882A - Recovering group data between mobile systems - Google Patents

Abstract

A method for recovering group data between mobile systems, which incorporate at least one first mobile system, at least one second mobile system, and mobile stations, the method comprising the steps of maintaining (302) group data in a first database of the first mobile system, maintaining (303) group data in a database of the second mobile system. In the method, a recovery request is made (304) for recovering the group data, the second mobile system generates (306) one or more virtual attachment requests for the first database of said group, the second mobile system transmits (307) the virtual attachment request to the first database of the first mobile system, in response to the first virtual attachment request, the group data are updated (307) in the first database.

Description

RECOVERY OF GROUP DATA BETWEEN MOBILE SYSTEMS BACKGROUND OF THE INVENTION The invention relates to a method for recovering group data between mobile systems, which incorporates at least a first mobile system, which comprises a first database, at least a second mobile system, which comprises a second database and a service area, and whose mobile systems incorporate mobile stations as subscribers, the method comprising the steps of maintaining the group data in said first database of said first mobile system and maintaining the group data in said second database of said 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 radio telephones, the mobile systems having a cellular structure and each cell having at least one base station communicating by means of a or more radio connections with at least one mobile station. The radio connection is can establish through channels, of which one or more are typically used for signaling and the rest for traffic. The method of the invention is designed to be used particularly in so-called mobile trunk systems, which •? & z are typically company networks or private mobile radio networks used by the authorities, with the channels in these networks being assigned to one or more companies or authority organizations. In these networks, the subscribers have group numbers, apart from their own subscriber numbers, which indicate to which group call group the subscriber belongs, with which the calls intended for all the subscribers of said group, particularly the calls group, can be switched to these group subscribers. The invention can be applied to mobile systems with either digital or analogue paths by radio. Similar mobile systems are described, for example, in the publications of the British Ministry of Commerce and Industry MPT 1327, A Signaling Stardard for Trunked Land Mobile Radio Systems, January 1988, revised and reprinted in November 1991, issued by the Radiocommunication Agency. , and MPT 1343, Performance Specification, January 1988, revised and reprinted in September 1991, issued by the Radiocommunication Agency. A group call is one of the key functions in a mobile radio private network. A group call is used, among other things, in various operations involving several participants, particularly when a whole group must know at all times how things are going. A group call is a call in which all participants can take turns speaking and listening to each other. In the group call the entire group is called by a call number. An individual unit by radio,? X example, a mobile station or a telephone by radio, that is, a station s! rtádo faith. it can belong to a plurality of groups which are programmed in the mobile station. Programming can be done permanently, but it can also be changed by the user or even by the system. Each mobile system can maintain, in the base stations, a file related to each group number. A group call may cover one, several or all of the base stations in the service area of a mobile service switching center and a plurality of mobile service switching centers, or a group call may be established within the area of service of several mobile systems. When a group call is established, a traffic channel is assigned to all base stations related to the group, and each of these base stations transmits, in the assigned traffic channel, a group call request which contains the number and group information. 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. In this way, the mobile station that is registered in the predetermined operating area of 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 radio telephones registered in said mobile system are stored in the database of the mobile trunk system, for example in the switching center or in its location recorder of visitor or in the home location recorder. The group data (group profile) contain data that inform the subscribers of said group, or some subscribers of the group, of available or activated services, for example, of complementary services. The group profile may also contain the definition of the importance, ie priority, of said group or its subset. In addition, the group profile can contain information about which subscribers belong to said group, ie a list that includes the identifiers of such subscribers that are allowed to participate in the communication with said group, for example in a group call, in the service area of said mobile system, in its specific location areas (location area) or in its specific base stations. This group profile is stored, for example, in a volatile RAM memory in which the data disappears, for example, when the power supply for the database is turned off, and at regular intervals in non-volatile memory media, for example on a hard disk in which the data is permanently maintained. When the RAM database sometimes turns on by itself, the group profile stored in the volatile memory disappears. Only the group data stored in the non-volatile memory, for example on the hard disk, remain. The disappearance of group data from the databases causes a serious problem in the group of a plurality of mobile systems, since if a certain group call is extended to the service areas of several mobile systems, the group data of The group call are stored in the databases of all said mobile systems. Therefore, if the database of any of the mobile systems has to be pushed down and since the database driven down can not continuously update the changes that have happened in the group group profile, these data may in the meantime change in the databases of other mobile systems, but remain unchanged in that database driven downward. As a consequence, the group data contained in the databases of different mobile systems become different, on the one hand in the database driven downwards and on the other in the databases that function normally. This difference between the group data of the databases may give rise to a situation in which a given mobile station is allowed to join a group call in a first mobile system, but in a second mobile system it is not allowed to said mobile station joining the same group call, since the data of said group has not been updated in said mobile system, nor in its database. In accordance with the prior art, it is possible to try to maintain the contents of the databases of various mobile systems in a consistent manner using the so-called recovery. The recovery method uses a normal network sequence of mobile systems, or similar, by which the sequences of connection and disconnection sent by the subscriber terminals operating in the network are processed, directing the requests to a group of subscribers. another network. In the TETRA mobile system this sequence is an ANF-ISIMM sequence. This sequence is described in the specification TETRA ETS 300 392-3-5, Part 3: Inter-working basic operations; Part 3-5: Aditional 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 that mobile system is not the group's home mobile system. In the TETRA mobile system, the domestic mobile system is SwMI, domestic and correspondingly, the visited mobile system is SwMI visited. The visited mobile system communicates in this way the connection request to the domestic mobile system of the group which stores it in its database of information about the connection and responds to the visited mobile system by sending it the group profile. The visited mobile system stores the connection data and other group data in its database. The group data is kept stored in the database of the visited mobile system as long as there is at least one valid connection request for that group. When the visited mobile system receives a connection request from the subscriber terminal, any of the following procedures can be applied: 1) If several connections for the same visited mobile system, only once to the mobile system; co after receiving the first connection request. The home mobile system of the group call is the system in the database in which the group profile of said group is stored, for example. 2) The procedure described above can be complemented with a definition of the so-called "important user": important subscribers can be defined in the group, and the connection request sent by these is always communicated to the group's mobile home system. Therefore, important subscribers are paid with priority. 3) Alternatively, the visited mobile system always sends the connection request to the home mobile system after receiving a connection request from a subscriber terminal. In accordance with a corresponding principle such as the one described above, the visited mobile system communicates one or more disconnection requests received from subscribers by radio to the domestic mobile system. Disconnection requests are communicated one for each group or important subscriber or important user. Therefore the connection data is deleted from the database of the home mobile system and the connection data and correspondingly, the other group data is deleted from the databases of the visited mobile systems.

If the visited mobile system sends the. requesting connection to the domestic mobile system only once when receiving the first connection request, the disconnection request is sent to the home mobile system only after it is received from the last subscriber connected to said group in the visited mobile system. All the data of said group is therefore deleted from the database of the visited mobile system. Furthermore, as far as this subscriber is concerned, the connection data of said subscriber is deleted from the database of the domestic mobile system of the group and of the domestic mobile system of the subscriber. A disconnection request received from an important user always erases the connection data. referring to said subscriber in both databases. In addition, the above rule applies to a disconnection request received from an important user, if said user / subscriber is the last subscriber of the group. If the visited mobile system always sends a connection request to the home mobile system after receiving connection requests from a subscriber terminal, the disconnection request is also always sent to the home mobile system. If the disconnection request comes from the last subscriber connected to said group in the visited mobile system, all the data of said group is deleted from the database of the visited mobile system. Furthermore, as far as this subscriber is concerned, the connection data of said subscriber is deleted from the group database and from the home mobile system of the subscriber.

Figure 1 illustrates a radio subscriber "SwMI / MM '101 visited, a visited mobile system" SwMM / FE3' 102 visited "and a home mobile system SwMI / FE2 '103. The figure shows the parameters transmitted in each message or signal GTSI, ie the 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 they are only communicated to the home mobile system, in other words, if the important subscribers are not favored or prioritized and all connection requests are not communicated In Figure 1, the mobile station 101 sends a connection request 105 through wherein the mobile station wishes to be connected to a group within the service area of the visited mobile system referred to In response to the aforementioned request, the visited mobile system verifies whether or not s that the visited mobile system database is ready to support the use of that group. If affirmative, the visited mobile system passes the request for connection to the domestic mobile system FE2 103 of the group. The home mobile system verifies whether or not its database is ready to support the use of said group in the mobile system visited for said subscriber. If affirmative, the home mobile system transmits the data of said group to the visited mobile system which sends an acknowledgment. After receiving it, the home mobile system sends an acknowledgment to the visited mobile system 102 that the complete sequence "" 1"'has proceeded The visited mobile system further recognizes the mobile station 101. The sequence described above is an example of a prior art method, in which the first subscriber / mobile station wishes to be connected to a group in the service area of said mobile system in a situation in which the connection is viable.

BRIEF DESCRIPTION OF THE INVENTION The objective of the invention is to provide a method and a team that implement the method so that the above problems can be solved. This is achieved with a method characterized in that the method further comprises the following steps: A recovery request is made to retrieve group data; the second mobile system generates one or more first virtual connection requests for the first database of said group; the second mobile system sends the first virtual connection request to the first database of the first mobile system; in response to the first connection request virtual, said group data is updated in the first database. The invention also relates to an arrangement for recovering group data between mobile systems, in which there is at least one first mobile system comprising a first database where -jiM-Zi, -, keep the group data? || at least one second km mobile system comprising a second tlate base where said group data is maintained, and in which there are mobile stations. The arrangement, according to the invention, for recovering group data between mobile systems is characterized in that the first mobile system comprises first generation means for generating a virtual connection request for the second database and for transmitting the request for virtual connection to the second database of the second mobile system, in which the second database is arranged to update the group data in the second database in response to said virtual connection request, and in that the second system mobile comprises the second generation means for generating a virtual connection request for the first database and for transmitting the virtual connection request to the first database of the first mobile system, in which the first database is arranged for update the group data in the first database in response to the virtual connection request. The invention is based on the idea that the recovery of subscriber group data can be performed in such a way that a virtual connection request, generated by the system, is sent to each visiting subscriber from a visited mobile system or a visited node. to the home mobile system or to the home node, whereby the group data and possibly the location and subscriber data relating to the subscriber are *?% £ ^. - ^ ¡8Ml5?.? ^ 5J updated in all the databases in accordance with the normal connection sequence. The purpose of the invention is to recover the data of the group call groups between mobile systems connected to each other by sending a connection request to the domestic mobile system of each group, similar to a normal connection request, generated by the visited mobile system. , for each group of other mobile systems in use in the visited mobile system, whereby the group data is updated in the mobile systems in accordance with the normal connection sequence. The invention also relates to an idea, in accordance with which the domestic mobile system maintains a record, during recovery, of which connection data is processed during recovery. When the home mobile system receives a notification from the visited mobile system that the participation of the visited mobile system has ended, the home mobile system goes to its database and compares whether there is connection data concerning the visited mobile system that has remained unprocessed, because the visited mobile system did not notify them. The home mobile system transmits said connection data to the visited mobile system by means of a virtual connection request in accordance with the normal connection sequence. The normal connection sequences 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 subsequently corrected the corresponding disconnection data. The visited mobile system may reject the connection request also for some 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 it retrieves all the connection data related to the visited mobile system from its database and transmits them to said visited mobile system. An advantage of this procedure is simplicity, since it is not necessary to keep records. However, in this case the consumption of resources is not optimal. The invention relates to a method and an arrangement for recovering data of group call groups, ie a group profile, of guest subscribers between mobile systems and / or databases of mobile networks. The invention is used to detect and correct inconsistencies in the group profiles in connected TETRA mobile networks. An advantage of this type of method according to the invention is that it solves the problems of the solutions of the prior art. The method and arrangement according to the invention also have the advantage that the method uses normal group data processing sequences. That simplifies the implementation of recovery and improves reliability. The invention also improves the loading problems of mobile systems, since by means of the invention the load caused by the recovery is adjusted automatically in accordance with the loading conditions of each mobile system or connections between mobile systems, if the Recovery is carried out in accordance with the most preferred mode, ie synchronization in the transmission using acknowledgments. In addition, the invention has an advantage that no data needs to be deleted from the databases, unless there is more correct data compared to the data previously stored in the database. The invention also has the advantage that the method of the invention allows to initiate in a variety of ways, for example, periodically, when ordered by the user or as a result of a detected or assumed failure. A further advantage of the invention is that it is suitable for background processing in the mobile system. The invention also has the advantage that it is not limited to pulses from the subscriber terminals. Therefore, with the method of the invention, recovery is possible in cases in which there is no or no impulse coming from the subscriber.

Furthermore, an advantage is that with it it is possible to make the rate of charge and load adjustable according to other loads in mobile systems. The invention has the advantage that the recovery rate implemented with it does not depend on a random time of arrival of the impulses. The invention has the advantage that it does not consume any radio resources. The invention has the advantage that when synchronizing the transmission of a new connection request with the recognition of the previous request, the recovery load can be adjusted in accordance with the total load, when there is available capacity. The invention has the advantage that an additional load caused by it is minimal, when part of the system is loaded for some other reason. The invention has the advantage that when operated in accordance therewith, a node of the mobile system loads another node or connection in a way in which it can not be handled by them.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in greater detail in conjunction with the preferred embodiments with reference to the accompanying drawings, in which Figure 1 illustrates a message diagram of a prior art method. Figure 2 is a flow chart of the operation of the method of the invention. Figure 3 is a block diagram of an arrangement according to the invention.

DETAILED DESCRIPTION OF THE INVENTION Recovery Figure 2 shows a flow chart of the operation of the method of the invention. Correspondingly, figure 3 shows an arrangement, by means of which the method of figure 2 can be implemented. The block diagram of figure 3 illustrates an arrangement for retrieving group GD data between mobile systems S1, S2, S3, wherein there is at least a first mobile system S1 comprising a first database DB1 and a service area SA1, at least a second mobile system S2 comprising a second DB2 database and a service area SA2, and in which there are the mobile stations MS1, MS2. The described mobile systems are connected to each other with telecommunication connections T on the inter-system ISI interface between the mobile systems. The ISI interface and its operation are described in the aforementioned ETSI specification ETS 300 392-3-5. The mobile systems have at least one mobile services switching center MX1 to MX3, to which are connected at least one database DB1 to DB2 and typically one or more radio units, a base station BS can serve as a of such units. The recovery of group data can be initiated at the initiative of either the group mobile home system or the visited mobile system. Recovery can be initiated, for example, periodically, at the user's disposal or as a result of a detected or suspected failure. Recovery may involve one or more mobile systems visited and one or more home mobile systems. The recovery can be carried out simultaneously or successively for a plurality of mobile systems. If the recovery is established at the initiative of the domestic mobile system, it transmits a request for the start of recovery to all those mobile systems visited with which recovery is desired. Upon receiving the establishment request, the visited mobile system initiates the recovery of the data of said groups of domestic mobile systems that exist in their databases. * * > »- ^ ^ e If the recovery is established on the initiative of the visited mobile system, it transmits a recovery start notification to the home mobile systems with which it wishes to recover, and initiates the recovery of data from said mobile system groups that exist in their databases. If desired, the recovery of group data can be combined with the retrieval of location and subscriber data, for example, recovering the group of data specifically for the subscriber that refer to each subscriber immediately, or for example, recovering the group data after the location and subscriber data of all the subscribers have been retrieved. If desired, the arrival of establishment messages can be ensured, for example, with a transmission protocol comprising acknowledgments and retransmission of the establishment message, if necessary. The recovery can be performed in such a way that the visited mobile system goes to its database and transmits in accordance with its normal connection sequence one or more virtual connection requests for each group to the domestic mobile system of each second network group , found in its database, participating in the recovery. The virtual connection requests contain the age of said connection data. The domestic mobile system accepts the connection request from the visited mobile system, if the home mobile system has not stored subsequent data from a home mobile after - 308 update the corresponding connection data in its database and transmits 309 the data of that group towards the visited mobile system. The home mobile system may reject the connection request in addition for some other reason, for example, but the subscriber has been allowed to join the group. The home mobile system also verifies, in accordance with the normal sequence, whether the subscriber is registered in said visited mobile system in accordance with the information in the home mobile system, if not, the home mobile system initiates a normal sequence of correction of location data and similar data. The connection data and other data (group profile) relating to the group are updated both in the visited mobile system and in the domestic mobile system in accordance with the normal connection / disconnection sequence. In addition, the visited mobile system always verifies that the subscriber, which is connected to the group, also has a valid record for said visited mobile system. If the record does not exist, the connection data is deleted according to the normal sequence of connection / disconnection. Mobile systems do not necessarily store any group call disconnect data in their databases after the normal disconnection sequence has been completed.

The visited mobile system transmits virtual connection requests to home mobile systems in accordance with 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 having received the first connection request for said group, in the recovery only one virtual connection request is transmitted per group. If the aforementioned procedure is complemented with a definition of the so-called "important user", in the recovery a virtual connection request is transmitted for each important subscriber in the group, with the condition that the group call implies one or more important subscribers or with priority. 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 terminal, a virtual connection request is transmitted in the recovery for each subscriber connected to the group. If the normal sequence is optimized to the effect that the home mobile system does not transmit the group profile of a group call to the visited mobile system each time it receives a connection request from the visited mobile system, the recovery sequence of the invention must be complemented in such a way that the transmission of the group profile is ensured in the recovery. This can be done so that, in the recovery, a) in the virtual connection message, the visited mobile system requests, at least once for each relevant group, the domestic mobile system that transmits the group profile to said system mobile visited. This solution requires a field for this purpose in the ISI connection message between different mobile TETRA systems, or b) the home mobile system ensures that it transmits the group profile at least once for each relevant group to each relevant visited mobile system. During recovery, the home mobile system keeps track of what connection data is processed in the recovery. When the home mobile system receives a notification from the visited mobile system that the participation of the visited mobile system has ended (see recovery completion), it goes to its database and compares whether the database contains connection data that they refer to the visited mobile system and that they remain unprocessed, since the visited mobile system did not notify them of them. The visited mobile system generates the second connection request 310 and transmits 311 this virtual connection data to the visited mobile system in the virtual connection requests in accordance with the normal connection sequence. Virtual requests contain the age of said data. The visited mobile system accepts the connection request from the home mobile system, if the visited mobile system has not * * stored subsequent subsequent disconnection data. The visited mobile system then updates 312 in its database said group data, of which the home mobile system reported. The visited mobile system can reject the connection request also for some other reason, for example, if it is 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 it retrieves all the connection data related to said visited mobile system from its database, generates 310 the second requests of the mobile system. virtual connection and transmit 311 these to said visited mobile system. Simplicity is an advantage of this procedure, since it is not necessary to keep a record. On the other hand, the consumption of resources is not optimal in this case. If desired, the group data recovery can be combined with the retrieval of location and subscriber data, for example, by recovering group data specifically for the subscriber to refer to each subscriber as soon as the subscriber's location and subscriber data has been retrieved, or for example, by retrieving the group data after they have been retrieved. recovered the location and subscriber data of all the subscribers. If desired, the recovery of group data between the subscriber terminals and the mobile systems can be combined with the recovery of group data between the mobile systems. The order of -y * $ The completion of these reinterpretation operations can be accomplished in a desired manner. If desired, the arrival of messages sent in a sequence can be ensured, for example, with, * transmission protocol that includes a retransmission of the message, if necessary. The participation without notice of the visited mobile system ends for each domestic mobile system, when it detects having recovered the data of all the groups in said mobile network. The visited mobile system transmits a notification to the home mobile system of each group call 10 formed in its coverage area of the termination of its participation. The unannounced participation of the visited mobile system ends completely, when all the group calls of the domestic mobile system are processed. The domestic mobile system processes for each mobile system visited the connection data that has remained unprocessed in the participation of the visited mobile system, when the latter receives a notification of termination of the participation of said visited mobile system. The recovery ends for each visited mobile system, when the connection data is processed with said visited mobile system. Recovery ends in the domestic mobile system, after that it has received a notification of termination from all visited mobile systems with which the recovery has been made, and after the domestic mobile system has processed the unprocessed connection data in its database. If desired, the mobile system < »V *, 'S ~ Y ~ domestic can also notify the mobile systems visited participants of the recovery completion. This data, for example, can be used for user information. In the method of the invention, the group data GD is maintained 302 in the first database DB1 of the first mobile system S1, and additionally, the group data GD is maintained 303 in the second database DB2 of the second mobile system S2. In this case, as described in the above specification part in conjunction with the problems of the prior art, the problem is how to keep the group data in the DB1, DB2 databases identical and consistent in relation to one another. In the method of the invention, this problem is solved in such a way that a recovery request is made to retrieve the GD group data. The second mobile system S2 generates 306 a virtual connection request for the first database DB1 and transmits 307 that request to the first database DB1 of the first mobile system S1. In response to that virtual connection request, the group data GD is updated 308 in the first database DB1. In accordance with one embodiment of the invention, the first mobile system S1 makes the aforementioned recovery request by transmitting a recovery establishment message to all those other mobile systems S2, S3, with which recovery is desired, and in response to this establishment message the other mobile systems S2, S3 begin to recover their group data. Alternatively, the second mobile system S2 makes the recovery request by sending a recovery establishment notification to the first mobile systems S1 with which it wishes to perform the group data recovery. In response to the recovery establishment notification made, the second mobile system S2 begins to retrieve the group (GD) data in its second DB2 database. The invention also relates to an idea that during recovery the home mobile system keeps a record of what connection data is processed in the recovery. When the domestic mobile system receives a notification from the visited mobile system of termination of the participation of the visited mobile system, it goes to its database and compares whether the database has connection data that refer to said mobile system visited and that remain unprocessed, since the visited mobile system did not notify you of them. The home mobile system generates 310 and transmits 311 said second connection data to the visited mobile system in a virtual connection request in accordance with the normal connection sequence. In addition, alternatively, the home mobile system does not keep a record of the connection data transmitted by the visited mobile system, but it retrieves all the connection data related to the visited mobile system from its database and transmits them to said visited mobile system. Simplicity is an advantage of this procedure, since it is not necessary to keep a record. On the other hand, the consumption of resources is not optimal in this case. In the method of the invention, apart from the GD group data recovery, the location data and subscriber data of the subscribers MS1, MS2 introduced in the group specified in said first and second databases DB1 and DB2 can be retrieved specifically for the subscriber. In the method of the invention, the arrival of recovery requests and said virtual connection requests are secured in a manner such that the recovery request and the virtual connection requests are retransmitted, if necessary. In addition, according to the invention, the virtual connection requests contain information about the age of the connection data. In response to the age information of the connection data contained in the first virtual connection request the first mobile system S1 compares that information with the ages of the possible disconnection data stored in the first mobile system S1, and if the age of the connection request is less than the ages of the disconnection data previously stored in the first mobile system S1, the first mobile system S1 accepts the virtual connection request transmitted from the second mobile system S2, in response to whose connection request to group call GC in connection is greater than the ages of the disconnection data previously stored in the first mobile system S1, the first mobile system S1 rejects the virtual connection request transmitted from the second mobile system S2. If said disconnection data and the connection request are in the same age, the connection request can either be accepted or rejected. It is possible to make this selection involve all the referring cases when the mobile system is implemented. Correspondingly, the second mobile system S2 processes the age of the second virtual connection request transmitted by the first mobile system S1. Figure 3 is a block diagram of an arrangement according to the invention. In the arrangement of figure 3, there is a group of mobile systems S1, S2, S3, in which there is at least a first mobile system S1 comprising a first database DB1, where the group data GD are maintained , at least a second mobile system S2 comprising a second DB2 database, where the group data GD are maintained, and in which group there are mobile stations MS1, MS2 of which at least some communicate in the call of group established within service area SA2 of at least said second mobile system S2.

The group of mobile systems may also include a third mobile system S3, in which a group call GC2 is maintained. This group call may be a second group call or a subset of the group call maintained in the service area of the second mobile system S2, whose group call is described here in greater detail. In the arrangement according to the invention, the second mobile system S2 comprises the generation means GM2, for generating a virtual connection request for the first database DB1 and for transmitting the aforementioned virtual connection request to the first database of data DB1 of the first mobile system S1, whereby the first database DB1 is arranged to update the group data GD in the first database DB1 in response to that virtual connection request. In the arrangement according to the invention, the first mobile system S1 comprises the generation means GM1 for generating a virtual connection request for the second DB2 database and for transmitting the aforementioned virtual connection request to the second database DB2 of the second mobile system S2, whereby the second DB2 database is arranged to update the group data GD in the second DB2 database, in response to that virtual connection request. In the method of the invention, the arrival of messages can be ensured, for example, with a transmission protocol, which comprises the retransmission of a termination message if necessary. For example, recognition messages can be used, which inform the sender if the recipient has received the transmitted message. If desired, the recovery of group data can be combined with the retrieval of location and subscriber data, for example, by retrieving the group data specifically for the subscriber that refer to each subscriber as soon as said data is retrieved. of location and subscriber, or for example, recovering the group data after the subscriber data and the location data of all the subscribers have been recovered. 10 The recovery rate and the recovery load can be adjusted automatically in accordance with the load factor of both the visited database and the domestic database in such a way that the connection requests are transmitted one by one so that the network does not send a new virtual connection request until the The previous application has been processed in both networks. Therefore, the network will not start processing the new virtual connection request until it has received an acknowledgment for the preceding virtual connection request from the other network. In case the network does not receive the recognition from the other network, the continuity of a sequence can be ensured in such a way that the network continues the recovery in a given period if recognition is not received. If desired, synchronization can be restricted to the transmission of a new message only: the network can process the new request for ^ S ^^ i ^^^^^^^^^^^^^^^ virtual connection even before receiving recognition for the preceding request, and consequently the new message can be transmitted more quickly. The method of the invention can be complemented with decision priorities between virtual connection requests and other transactions, such as normal connection requests. Alternatively, the rate and the load can be adjusted, for example, by pausing between the transmission of virtual connection requests. If desired, the home mobile system can notify the mobile systems visited of the recovery termination. This information can be used, for example, to announce to the users that any of the group data or even the subscriber data and the subscriber location data for a specific subscriber, mobile system, database or call has been recovered. of group. If desired, the arrival of the messages to be transmitted in the recovery sequence can be ensured, for example, with a transmission protocol comprising retransmission of the message, if necessary. Ensuring the arrival of messages is an advantageous procedure, since it increases reliability. It is an advantageous way to combine the recovery of group data with the retrieval of location and subscriber data by retrieving the group data relating to each subscriber specifically for the subscriber as soon as the location data and the subscriber subscriber data have been recovered. , since it is easier to handle a failure in which conflicting location data is detected in home mobile systems in connection with the recovery of group data. Therefore, the conflict can be corrected by restarting a specific recovery sequence for the subscriber from the location data retrieval, and the sequence corrects both the location data and the group data. The synchronization of the transmission of virtual connection requests with the acknowledgments coming from the home mobile systems is a good way of implementation, since with it the recovery rate and the recovery load can be adjusted automatically in accordance with the load factor of both the mobile systems visited and the domestic mobile systems. In addition, this method is simple to implement. It is obvious to those skilled in the art that the basic idea of the invention can be implemented in a variety of ways in terms of technological advances. Therefore the invention and its embodiments are not restricted to the examples described above, but may vary within the scope of the appended claims.

Claims (16)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for recovering group data (GD) between mobile systems (S1, S2, S3), which incorporates at least a first mobile system (S1), comprising a first database (DB1), at least a second mobile system (S2), comprising a second database (DB2), and whose mobile systems incorporate mobile stations (MS1, MS2), the method comprising the steps of maintaining (302) the group data (GD) in said first database (DB1) of said first mobile system (S1), maintaining (303) said group data (GD) in said second database (DB2) of said second mobile system (S2), making a request for recovery (304) to recover group data (GD), characterized in that the method also comprises the following steps: the second mobile system (S2) generates (306) one or more first virtual connection requests for the first database of the first mobile system (S1), the second mobile system (S2) sends (307) the first request virtual connection tud to the first database (DB1) of the first mobile system (S1), in response to the first virtual connection request the group data (GD) are updated (308) in the first database (DB1) ) and wherein at least one virtual connection request is sent from the second mobile system for each group of the first mobile system found in the second database of the second mobile system.

2. A method according to claim 1, further characterized in that at least one virtual connection request is transmitted from the second mobile system for each important subscriber connected to a group that is formed in the second mobile system.

3. A method for recovering group data (GD) between mobile systems (S1, S2, S3), which incorporate at least a first mobile system (S1), comprising a first database (DB1), for at least one second mobile system (S2), comprising a second database (DB2), and whose mobile systems incorporate mobile stations (MS1, MS2), the method comprising the steps of maintaining (302) the group data (GD) ) in said first database (DB1) of said first mobile system (S1), maintaining (303) said group data (GD) in said second database (DB2) of said second mobile system (S2), making a recovery request (304) for recovering the group data (GD), characterized in that the method further comprises the following steps: the second mobile system (S2) generates (306) one or more first virtual connection requests for the first base data (DB1) of the first mobile system (S1), the second mobile system (S2) sends ( 307) the first virtual connection request to the first database (DB1) of the first mobile system (S1), in response to the first virtual connection request, the group (GD) data on the first base are updated (308) data (DB1) and wherein from the second mobile system is transmitted at least one virtual connection request for each subscriber connected to the group of the first mobile system found in the second database of the second mobile system.

4. A method according to claim 1, 2 or 3, further characterized in that in connection with said update step (308), said group data is transmitted from the first mobile system to the second mobile system at least once during recovery.

5. A method according to claims 1, 2 or 3, further characterized in that in connection with said update step (308), said group data is transmitted from the first mobile system to the second mobile system each time when the First mobile system receives said virtual connection request.

6. A method according to claim 1, 2 or 3, further characterized in that the first mobile system (S1) makes the recovery request by transmitting a recovery establishment message to all those different mobile systems (S2)., S3) with which recovery is desired, in response to the recovery establishment message, the other mobile systems (S2, S3) begin to retrieve their group data.

7. A method according to claim 1, 2 or 3 further characterized in that the second mobile system (S2) makes the recovery request transmitting a recovery establishment notification to those first mobile systems (S1) with which you want to perform the recovery of group data, in response to the reconfiguration set-up notification made, the second mobile system (S2) begins to retrieve the data8 gru8glGD) contained in its second database (DB2).

8. A method according to claim 1, 2 or 3, further characterized in that apart from the recovery of group data (GD), you can also retrieve the location data of subscribers (MS1, MS2) entered in the group specified in said first and second database (DB1) (DB2).

9. A method according to claim 1, 2 or 3, further characterized in that the arrival of the recovery requests and said virtual connection requests is ensured in a manner such that the recovery requests and the virtual connection requests are re-transmit, if necessary.

10. A method according to claim 1, 2 or 3, further characterized in that the virtual connection request contains information about the age of said connection request.

11. A method according to claim 10, further characterized in that in response to information about the age of the age of the connection data contained in the first virtual connection request, the first mobile system (S1) compares that information with the ages of the possible disconnection data stored in the first mobile system (S1), and if the age of the connection request is less than the ages of the disconnection data previously stored in the first mobile system (S1), the first mobile system (S1) accepts the virtual connection request transmitted from the second mobile system (S2), in response to whose virtual connection request the group data (GD) is updated in the first database (DB1), while that, if the age of the connection request is greater than the ages of the disconnection data previously stored in the first mobile system (S1), the first mobile system (S1) rejects the request of virtual connection transmitted from the second mobile system (S2).

12. A method according to claim 1, 2 or 3, further characterized in that in the method, the first mobile system maintains a record in its database of the first virtual connection requests transmitted by the second mobile system, on the basis of said registration, the first mobile system generates and transmits the second virtual connection requests to the second mobile system, for the groups in the service area of the second mobile system, whose domestic mobile system is said first mobile system, but whose connection requests have not been entered in said register, in response to the second virtual connection requests transmitted by the first mobile system, the second mobile system updates the group data on the basis of the second connection requests.

13. A method according to claim 12, further characterized in that in response to information on the age of the connection request contained in the second virtual connection requests, the second mobile system (S2), compares that information with the ages of the possible disconnection data stored in the second mobile system (S2), and if the age of the connection request is less than the ages of the disconnection data previously stored in the second mobile system (S2), the second system mobile (S2) accepts the virtual connection request transmitted from the first mobile system (S1), in response to whose virtual connection request the group data (GD) is updated in the second database (DB2), whereas, if the age contained in the second virtual connection request is greater than the ages of the disconnection data previously stored in the second mobile system (S2), the second mobile system (S2) ) rejects the virtual connection request transmitted from the first mobile system (S1).

14. A method according to claim 1, 2 or 3, further characterized in that in the method, the first mobile system retrieves from its database all connection data relating to the second mobile system kept therein and transmits them to the second mobile system, which updates the group data of said groups based on the connection data.

15. A method according to claim 1, further characterized in that in the method, the first mobile system retrieves from its database all connection data relating to the second mobile system maintained in it and transmits them to the second mobile system , which updates the group data of these groups based on the connection data.

16. - An arrangement for recovering group data between mobile systems (S1, S2, S3), which incorporates at least a first mobile system (S1), comprising a first database (DB1) where the group data ( GD) are maintained, at least a second mobile system (S2), which comprises a second database (DB2) where said group data (GD) are maintained, and whose mobile systems incorporate mobile stations (MS1, MS2 ), characterized in that the first mobile system (S1) comprises the first generation means (GM1) for generating a virtual connection request for the second database (DB2) and for transmitting said virtual connection request to the second database (DB2) of the second mobile system (S2), whereby the second database (DB2) is arranged to update the group data (GD) of the second database (DB2) in response to the virtual connection request , and because the second mobile system (S2) comprises the second generation means (GM2) for generating the virtual connection request for the first database (DB1), and for transmitting said virtual connection request to the first database (DB1) of the first mobile system (S1), with which the first database (DB1) is arranged to update the group data (GD) of the first database (DB1) in response to the virtual connection request.