EP1977580A1

EP1977580A1 - Method and server for establishing a communication link between communication terminals in a preselected group

Info

Publication number: EP1977580A1
Application number: EP06841386A
Authority: EP
Inventors: Thomas Wolff
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2006-01-12
Filing date: 2006-12-15
Publication date: 2008-10-08
Also published as: CN101379793A; MX2008008991A; US20090270048A1; WO2007082615A1; DE102006002434B3

Abstract

The invention relates to a method for establishing a communication link between communication terminals (KEGl, KEG2, KEG3) which are associated with a preselected group (G) of communication terminals. According to said method, a start message (1) is captured by a server (SI, S2) of a communication link (KNl, KN2), which is sent by the communication terminal (KEG3), the preselected group is determined by the server using information transferred in the start message via the communication terminal (KEG3) and is associated with the communication terminal (KEG3). Also, a link message (2) is transferred by the server (SI, S2) to the communication terminal (KEG3). The server (SI, S2) captures a link confirmation message (3) which is sent by the communication terminal, whereby the communication link between the communication terminal (KEG3) and additional communication-ready communication terminals (KEGI, KEG2) of the group, is produced. The invention also relates to a server.

Description

METHOD AND SERVER FOR MANUFACTURING A COMMUNICATION CONNECTION BETWEEN COMMUNICATION TERMINALS IN A PRE-SELECTED GROUP

Method and server for establishing a communication connection between communication terminals 5

The invention relates to a method for establishing a communication connection between communication terminals which belong to a preselected group of communication terminals. Furthermore, the invention relates to a server.

10

In modern communication networks services are increasingly offered in which not only - such as in the traditional telephony - communi ^¬ adorn two communication terminals, but where more than two Kommunikationsendge-

15 rate communicate with each other. In such services, a communication link is established between (generally) a plurality of communication terminals that form a group of communication terminals or belong to a group of communication terminals. Examples of such

20 group communication services are the so-called push-to-talk service, in each case a communication terminal can send voice messages simultaneously to several other communication ^¬ tion terminals of the group. Another example is the so-called chat service, in which a communication

25 the group text messaging terminal simultaneously to the walls ^¬ ren communication terminals of the group can send. To the time required for such group communication services ^¬ communi cation connection established between the communication terminals of the group, it is conceivable that a communication

The function of a group responsible person (so-called "originator") is the end device of the group: The user of this special communication terminal would then have to ensure that the communication connection to the respective other communication terminals of the group will be produced. However, such a method would be complicated and un ^¬ convenient for the user of this communication ^terminal .

The invention has for its object to provide a method and an apparatus with which the establishment of a communication connection between communication terminals of a group can be easily and conveniently performed.

This object is achieved according to the invention, by a procedural ^¬ ren for establishing a communication link between communication terminals which belong to a preselected group of communication terminals, in which method - a Startnach ^¬ is received report from a server of a communication network, which was sent from a communication terminal,

- in the start message übertra ^¬ genes information about the communication terminal superiors the selected group is transmitted from the server based on a determined, belonging to the communication terminal, and

- Is transmitted from the server, a connection message to the communication ^¬ tion terminal and is received from the server a ^¬ subsequently sent from the communication terminal connection confirmation message, whereby the communication ^¬ tion connection between the communication terminal and wei ^¬ teren communication ready communication terminals of the group is made. It is particularly advantageous that none of the communication terminals of the group needs to take over the function of the group responsible. Rather, the communica tion network ^¬ is advantageously from a server receiving the sent by the communication terminal start message, the selected group determines exceeded the connection message to the communication terminal and receive the connection acknowledgment message sent by the communication terminal. As a result, the communication connection between the communication terminal and the other communication ready Kommunikationsendge- rates of the group is established. On the part of the communication ^¬ terminal device advantageously only the start message needs to be sent to the server. The ^further method steps then take place automatically and essentially without the intervention of the communication terminal. In this method, no communication terminals are required with a group responsible function.

The method can proceed in such a way that the server receives the start message, which was sent by the communication terminal after it was switched on or after activation of a communication function of the communication terminal. The start message may preferably be sent automatically from the communication terminal immediately after its activation to the server. Characterized ER is sufficient that immediately after the communication terminal ^¬ run the process steps for manufacturing the communi ^¬ cation compound and the communication terminal without appreciable delays to the other communica tion ^¬ terminals of the group is able to communicate. Alternatively, the start message can also be sent after a communication end device-side activation of a communication function. In this case, the communication terminal may preferably be in two different modes to be operated: at non-activated communication function not communi- is established to the other communication terminals of the group cation compound and the communication terminal can in her ^¬ kömmlicher manner (for instance be used specific for classic ^¬ telephone calls between a calling communication ^{terminal ¬} device and a called communication terminal); whereas if the communication function is activated, the communication connection to the other communication terminals of the group is established.

Preferably, the communication connection can be made to a group communication service, in particular a push-to-talk service or a chat service, Sieren to reali ^¬.

The method can proceed so that the server simulates an additional communication terminal of the group, which cation compound by means of the connect message, the production of the communi ^¬ caused between the communication terminal and the other communication-ready communication terminals of the group. This variant of the method according ^¬ contemporary has the advantage that it does not violate standards, ie, the method can be used with standard compliant group communication services.

Advantageously, the method can proceed in such a way that a message is used as start message with which the communication terminal registers with the communication network for the use of Internet protocol-based services. This variant but has the advantage is that for the novel process no additional start ^¬ message requires that in communications ^¬ networks already used message with which the communi ^¬ cation terminal for the use of Internet protocol-based registered services, in addition as Start message is used.

Preferably, as such a start message, the session initiation protocol message "REGISTER" known as such may be used. Advantageously, "INVITE" be used as a connection message as sol ^¬ che known protocol message Session Initiation.

The abovementioned object is likewise achieved ^{according to the} invention by a server for a communications network which is designed

for receiving a start message sent by a communication terminal,

- For determining a preselected group of communication terminals, which belongs to the communication terminal, based on an information transmitted in the start message information about the communication terminal, and - for transmitting a connection message to the communication ^¬ tion terminal and for receiving a then sent by the communication terminal Verbindungsbestätigungsnach- by the communication connection between the communication terminal and further communication-ready communication terminals of the group is established. This server the start message, the communication link between the communication terminal and the other communication-ready communication terminals of the group may advantageously upon reception are prepared in a tes for the user of Kommunikationsendgerä ^¬ easy and convenient way automatically.

The server may include a user interface for modifying the group affiliation of communication terminals. In order can advantageously affiliation of communi ^¬ cation terminals changes to the group, that the group may be administered or managed. The server can be designed to implement a group communication service, in particular a push-to-talk service or a chat service.

The server can be configured such that it simulates an additional communication terminal of the group, which causes by means of the connection message to establish the Kommuni ^¬ cation connection between the communication terminal and the other communication ready communication terminals of the group. This advantageously makes it possible to use this server with standard-compliant push-to-talk-over-cellulary services.

Furthermore, the server can be designed to receive a start message with which the communication terminal registers with the communication network for the purpose of using Internet protocol-based services. As a result, the message sent by the communication terminal anyway for the purpose of registration can advantageously be received by the server, so that no additional message needs to be sent by the communication terminal.

Preferably, the server may be configured to receive a start message in the form of the Session Initiation Protocol message "REGISTER." This allows the use of the known message "REGISTER" as a start message.

Furthermore, the server can advantageously be designed to transmit a connection message in the form of the Session Initiation Protocol message "INVITE".

The invention will be explained in more detail below with reference to ^exemplary embodiments. This is in Figure 1 shows a first embodiment of a

Communication network with a group of communi ^¬ cation terminals, in

Figure 2 cation terminals, a second embodiment of a communication network with a group of communica ^¬ and

FIG. 3 shows an exemplary sequence of the method on the basis of a message flow diagram.

In Figure 1, a first communication network is shown Kl having a first Mobile Network MFNl, a first packet switched domain PSI, an Internet Protocol-based multi ^¬ media subsystem IMS, a server Sl in the form of a push-to-talk server, a second packet-switched domain PS2 and a second mobile radio network MFN2. In the first mobile radio network MFNl a first base station BSl and a second base station BS2 are arranged which (node SGSN = Serving GPRS Support) having a first Vermitt ^¬ switching center SGSNl the ers ^¬ th packet-switched domain PSl is connected. The first switching center SGSN1 is connected via a first gateway GGSN1 (GGSN = gateway GPRS support node) to a control unit CSCF (CSCF = call state control function) of the Internet protocol-based multimedia subsystem. In the multimedia subsystem IMS is still a home register HSS (HSS = Home Subscriber Server). The control unit

CSCF is connected to the server Sl. The server Sl includes a computer program A (A = application) for controlling the method steps of the method described. Next ^¬ down the server assigns to a database XDM (data storage), can be accessed through a user interface ^{(administration} interface) S.

Furthermore, the control unit CSCF via a second gateway GGSN2 with a second exchange SGSN2 the second linked packet-switched domain PS2. The second switching center SGSN2 in turn is connected to a third Basissta ^¬ tion BS3 and a fourth base station BS4 of the second mobile radio network MFN2.

Through the base stations BSl to BS4 five ^¬ communication terminals are Kegl, KEG2, KEG3, KEG4 KEG5 and the communica tion network ^¬ Kl connectable. The communication terminals KEG1 to KEG5 are in the exemplary embodiment GPRS-capable mobile phones (GPRS = general packet radio service). However, communication devices such as a portable computing ^¬ ners with a mobile radio interface, a palmtop, a fixed network phone can ^¬ or a personal computer can be used in the form in other embodiments. The five communication terminals KEG1 to KEG5 belong to a preselected group G of communication terminals, this group membership is symbolized by a dashed border.

In Figure 2, a second communication network K2 is shown, which differs from the described in connection with Figure 1 first communication network Kl essentially only in that the control unit CSCF not only with the push-to-talk server Sl, but in addition with a second server S2 in the form of a Session Initiation Protocol application server S2 (SIP application server) is connected. The program A is arranged in the second communication network K2 not in the push-to-talk server Sl, but in the SIP application server S2. In the second communication network K2 shown in FIG. 2, the method steps are controlled by the program A running in the SIP application server S2. This program A can access the data base XDM arranged in the push-to-talk server Sl and controls the (elementary) communication radio. functions of the server Sl start (for example, the push-to-talk over SIP functions), in particular to the connection message INVITE to ver ^¬ and the communication link of all the communication-ready communication terminals that belong to the same pre-selected communication group to manufacture. Alternatively, the database XDM can also be arranged in the server S2.

FIG. 3 shows a message sequence of the method according to the invention. In the following, by means of the Figu ^¬ ren 3 and 1, an exemplary sequence of the method according to the invention and the function of the server according to the invention explained. The following initial situation based ge ^¬ is inserted: between the communication terminals and Kegl KEG2 a communication connection has already been made; Via this communication connection, a push-to-talk service is realized, in which the communication terminals KEG1 and KEG2 participate. The communication terminals KEG1 and KEG2 participate in a push-to-talk session ("push-to-talk session") of group G. The push-to-talk service is also referred to as "group talk". The Push-to-Talk (PTT) service is implemented here via the packet-switched Internet protocol-based multimedia subsystem; In this context, this service is also known as "push-to-talk over Cellular" (PoC). A meeting of a group communication diene ^¬ tes is commonly referred to as "session".

A user of the communication terminal KEG3 also wants to participate in the push-to-talk service and therefore turns on his communication terminal KEG3. Directly to the A ^¬ switch of the communication terminal KEG3 toward sends the Kom ^¬ munikationsendgerät KEG3 a first start message 1 in the form of a SIP message "REGISTER" to the first communication ^¬ network Kl (arrow 1: REGISTER). This first start message 1 passes via the second base station BS2, the first switching center Vermitt ^¬ SGSNl, the first gateway GGSNl to the control unit CSCF of the multimedia subsystem IMS. Through this Startnach ^¬ "REGISTER" report is the third communication terminal logged KEG3 in a known manner at the multimedia subsystem IMS; it is registered subsystem multimedia, that the communication terminal KEG3 ready for communication ( "online") is the Internet. With this start message 1, therefore, the communication terminal KEG3 registers for the use of Internet Protocol-based services offered by the communication network K1. Subsequently, the start message 1 is forwarded to the push-to-talk server Sl and reaches the program A running in it. (In the embodiment described below by means of FIG. 2, the start message 1 is forwarded to the server S2 and reaches that in this expiring program A.)

In another procedure, the start message may also be before it is sent from the communication terminal KEG3 after it has been activated (e.g. by the user) on the communication terminal KEG3 a Kom ^¬ munikationsfunktion; This activation may for example take place by there ^¬ that the user on the Kommunikationsendge ^¬ advises KEG3 actuates a particular key.

After the server-side reception of the start message 1, the server (more precisely, the program A running in the server) reads out information contained in the start message and transmitted with the start message via the communication terminal KEG3. Tion terminal, this information over the communica ^¬, for example, as a telephone number (MSISDN = Mobile Station ISDN number) or as a Session Initiation Protocol address (z. B. user@domain.com) vorlie ^¬ gene. This information about the communication terminal loading writes exactly considered the user of Kommunikationsendge ^¬ Raets KEG3. Since, however, the user of the communication terminal KEG3 remains unchanged during the entire process sequence and this person has somewhat "personalized" the communication terminal KEG3 (for example, by inserting a personal SIM card into the terminal, SIM = subscriber identity module), this telephone number or This SIP address during the procedure, information about the terminal KEG3. In this sense, the term "information on the communication terminal" is used in the context of this description. Using this information about the communication terminal, the server S determines the pre ^¬ selected group to which it belongs, the communication terminal. In ^¬ formations about the group membership of the individual com- munikationsendgeräte are Da ^¬ tenbasis XDM (or in a recess provided for this purpose data base) stored in the server in the Sl. In the exemplary embodiment is stored in the server Sl as such group information that the communication terminal belongs KEG3 arrival of the group G and the group G in addition, the communication terminal device ^¬ Kegl KEG2, KEG4 and KEG5 belong. (In the embodiment described below by means of FIG. 2, the information about the group affiliation of the individual communication terminals can be stored in the server S1 or also in the server S2 in the database XDM or in a database provided specifically for this purpose.)

After evaluation of the group information, the information is present at the server S1 that the communication terminal KEG3 belongs to the group G. The server then sends

Sl a connect message 2 in the form of the as such well ^¬ th Session Initiation Protocol message "INVITE" to the communication terminal KEG3. This compound message 2 will be the first from the server Sl via the control unit CSCF Gateway GGSNl, the first switching center SGSNl and Ba ^¬ sisstation BS2 transmit to the communication terminal KEG3. The communication terminal sends KEG3 a conjunction acknowledgment message 3 in the form of a session initiator tion-Protocol message "OK" to the server Sl from this conjunction acknowledgment message 3 is terminal from the communication ^¬ KEG3 via the second base station BS2, the First switching center SGSNl, the first gateway GGSNl and the control unit CSCF transmitted to the first server Sl The server Sl receives this connection confirmation message 3. Upon receipt of the connection confirmation message 3 is from the push-to-talk server Sl, the communication link between the communication terminal KEG3 and the communication terminals KEG1 and KEG2 already participating in the push-to-talk service in the group G. By means of an information about the session ("session") contained in the connection message 2 and the connection confirmation message 3, eg by means of a in the form of a SIP address enthal ^¬ tenen name, arrange t the server SI the communication terminal KEG3 to this session and transmits the following voice messages from and to the communication terminal KEG3. Thus, there is now a communication link between the communication terminals KEGl, KEG2 and KEG3; These three communication terminals can now communicate with each other in the push-to-talk service, this Kommuni ^¬ cation is handled via the push-to-talk server Sl.

In this method, when establishing the communication connection (when establishing the connection), the server S1 simulates an additional communication terminal of the group G, so to speak a virtual sixth communication terminal. The server SI acts namely as a communication terminal in exporting ^¬ insurance such as a so-called "SIP user agent" (SIP tongue zeragent) of a SIP-enabled mobile phone. From the perspective of grain Namely communication terminal KEG3 seems the connection ^¬ message 2 come from an additional communication terminal, this additional communication terminal takes over the function of a group responsible. For the communication terminal KEG3 is therefore not to recognize that it does not communicate with a communication terminal, son ^¬ countries with the server Sl. This is particularly advantageous because the described method does not violate the standard "OMA PoC Control Plane, Candidate Version 1.0 - 04 Nov 2005, Open Mobile Alliance, OMA-TS-PoC-ControlPlane-Vl_0-20051104-C": The communication terminal KEG3 and subsequently also the communication terminals KEG4 and KEG5 do not realize that they communicate (nikationsendgerät and not with a commu ^¬) to a server in the manufacture of communications links fertil. the communication terminal KEG3, KEG4 and KEG5 therefore need to use in the inventive process not to be changed or adapted.

By means of the method described, another group communication service, for example a chat service, can also be realized. Then, instead of the push-to-talk server Sl, a chat server would be equipped with the program A, with this chat server realizing the chat service. The above-described procedures for establishing the communication connection between the communication terminals of the group would proceed in the same manner. The chat service is sometimes referred to as "chat-group-talk".

Next activates a user of Kommunikationsendgerä ^¬ tes KEG4 by pressing a button corresponding to the push-to-talk communication function of his communication terminal KEG4. The communication terminal then sends KEG4 a second start message 4 (arrow 4: REGISTER) to the server Sl. The server Sl receives this second start message 4, determined based on an information transmitted in the start message via the terminal KEG4 (for example, based on the SIP address Meier@yxz.com) using the database XDM that the communication terminal KEG4 belongs to the group G. The server S1 then sends a second connection message 5 (arrow 5: INVITE) to the communication terminal KEG4. The communication terminal KEG4 responds with a second connection confirmation message 6 (arrow 6: OK), which is received by the server S1. In response, the server Sl in the above manner, the communications ^¬ connection between the communication terminal KEG4 and already the push-to-talk service-using Kommunikationsend- fall Kegl KEG 2 and KEG3 ago. The push-to-talk service can now run between the four communication terminals KEGl to KEG4; Each of these communication terminals can send voice messages over the communication link to the other three communication terminals and receive from them.

While the method steps for preparing the compound tion communica ^¬ between the communication terminal and the communication terminals KEG4 Kegl run KEG2 and KEG3, has already a user of communication terminal KEG5 be switched communication terminal and the communication ^¬ function activated. Then, the Kommunikationsendge ^¬ sends advises KEG5 a third start message 7 (arrow 7: REGISTER) to the server Sl. The server Sl receives this third Startnach- Judges 7, (eg. A SIP address) read from the third start message over Wear ^¬ NEN information on the terminal and determines based on this transmitted information, that the communication terminal KEG5 also the group G belongs. The server S1 then sends a third connection message message 8 (arrow 8: INVITE) to the communication terminal ^¬ device KEG5. The communication device KEG5 responds with a third connection confirmation message 9 (arrow 9: OK). Then the communication connection between the communication terminal KEG5 and the communication terminals

KEGl to KEG4 of the group G produced. The push-to-talk server S1 implements the push-to-talk service, ie the push-to-talk server transmits, for example, voice message packets between the communication terminals of the group. Via the user interface S of the server S1, the group membership of the communication terminals can be changed (ie the group G can be administered or configured). About this user interface ^{(administration} interface) S of the push-to-talk server Sl can directly access the database XDM; such data ^¬ base is also known as "push-to-talk-over-cellular XML Document Management, XML = eXtended Markup Language (PoC XDM) Marked ^¬ net. This user interface can be accessed th various Ar ^¬. Access, for example, from a communication terminal (for example of communica ^¬ tion terminal KEG3) from done using the protocol XCAP (XML Configuration Access Protocol XCAP =). However, the user interface S can also be accessed by a network ^{operator of} the communications network ^K 1 or by a call center, wherein a user can change the network

Group membership of his communication ^terminal can use a so-called customer care portal. Finally, be ^¬ is also the possibility that a user of communica ^¬ tion terminals (for example, a user of the communication terminal KEG3) via a connected to the Internet computer using an Internet page / a web interface via the user interface S of the server Sl accesses the data ^¬ base XDM of the push-to-talk-over-cellular service. The latter possibility of change / admi- tration of the group membership of Kommunikationsendge ^¬ rätes advantageously allows to manage in a particularly comfortable manner via an internet site which Grup ^¬ penangehörigkeit and change it.

The method described above can also be carried out in the same way with the communication network K2 of FIG. 2 with the difference that the program A runs in the server S2 and the server S2 cooperates with the database arranged in the server S1. The server Sl emp ^¬ begins or then also sends the start messages, link messages and link confirmation messages and communicates with the server S2. Alternatively, the start messages, the connection messages and the connection confirmation messages can be transmitted from the control unit CSCF via the server S1 to the server S2 and vice versa or the start messages can be transmitted directly from the control unit CSCF to the server S2.

The described method of manufacturing a communica tion ^¬ connection between communication terminals of a group is essentially controlled on the server side. This method has a number of advantages:

- The preselected or preconfigured group (preferred ^¬ group) is persistent (permanent, non-volatile) (a communication terminal, for example, in case of failure or loss) must ie replacement of one of the mobile communication terminals of the group by another device, the preselected group not new To be administered because the group database (PoC XDM) is not changed in the server by the exchange of a mobile communication terminal. This is particularly advantageous when ^{communication} terminals weiterge- from one user to another user and be personalized, for example by inserting a new SIM card. Also in this case, no change in the database arranged in the server is necessary.

- The process can run with any communication terminals, if this for the group communication service

(for example, the push-to-talk service or the chat service) are suitable. The communication terminals do not have special functions relating to the method

(Special functions) needed; these special functions are realized on the server side. This is a considerable advantage both for vendors of communication terminals, for network operators of communication networks and for service providers. This

The advantage becomes particularly clear when one realizes that it is often very difficult to produce suitable terminals for newly developed innovative communication technologies or services in sufficient numbers and make them available to service users.

The server behaves like a communication terminal, so that the method can be realized without violating standards; the method can be readily implemented in existing communication networks.

-. Advantageously, the SIP message "REGISTER" is not only used to register the communication terminal in commu ^¬ nikationsnetz but at the same time, this message is used as a starting message this message is received from the server and starts the method ^sequence, for example, stimulates the Start message the program contained in the server Sl A, which controls the further Verfahrensab ^¬ running (the start message "triggers" the program). The program A can advantageously be stored either in the push-to-talk server S1 and run there or the program A can be stored in a server connected to the push-to-talk server (eg a SIP application -Server) be stored there and expire. This results in a process which can be variably adapted to the in the communication networks ^¬ present circumstances.

Claims

claims

A method for establishing a communication connection between communication terminals (KEG1, KEG2, KEG3) belonging to a preselected group (G) of communication terminals, wherein in the method

- From a server (Sl, S2) of a communication network (KNl, KN2) a start message (1) is received, which was sent by a communication terminal (KEG3), - from the server (Sl, S2) based on a in the start message (1 ) transmitted information via the communication terminal (KEG3) the preselected group (G) is determined, to which the communication terminal (KEG3) belongs, and

- From the server (Sl, S2) a connection message (2) to the communication terminal (KEG3) is transmitted and from the server (Sl, S2) thereafter from the communication terminal (KEG3) sent connection confirmation message (3) will receive emp ^¬ , whereby the communication connection between the communication terminal (KEG3) and further communication ready communication terminals (KEG1, KEG2) of the group is established.

2. The method according to claim 1, characterized in that - from the server (Sl, S2) the start message (1) is received, which was sent by the communication terminal (KEG3) after ^¬ sen switching on or after activation of a communication function of the communication terminal.

3. The method of claim 1 or 2, wherein a

the communication connection is established in order to realize a group communication service, in particular a push-to-talk service or a chat service.

4. Method according to one of the preceding claims, characterized in that

- The server (Sl, S2) simulates an additional communication terminal of the group (G), which causes by means of the connection ^¬ message (2) establishing the communication connection between the communication terminal (KEG3) and the other communication ready communication terminals (KEGl, KEG2) of the group ,

5. The method according to any one of the preceding claims, d a d u r c h e c e n e c e in that e

a message is used as start message (1) with which the communication terminal (KEG3) registers with the communication network (K1, K2) for the use of Internet protocol-based services.

6. Method according to one of the preceding claims, characterized in that - as the start message (1) the session initiation protocol message "register" is used.

7. Method according to one of the preceding claims, characterized in that - the session initiation protocol message "Invite" is used as the connection message (2).

8. Server (Sl, S2) for a communication network (Kl, K2), which is configured - for receiving a start message (1), which was sent by a communication terminal (KEG3),

for determining a preselected group (G) of communication terminals to which the communication terminal (KEG3) is attached listen to, on the basis of a transmitted in the start message (1) ^¬ formation via the communication terminal (KEG3), and

- For transmitting a connection message (2) to the commu ^¬ nikationsendgerät (KEG3) and for receiving a subsequently by the communication terminal (KEG3) sent connection confirmation message (3) through which the Kommunikationsver ^¬ binding between the communication terminal (KEG3) and weite ^¬ communication-ready communication terminals (KEG1, KEG2) of the group.

9. The server of claim 8, e e c e n e c e e n e by t

- A user interface (S) for changing the group membership of communication terminals.

10. The server of claim 8 or 9, wherein a

- This for the realization of a Gruppenkommunikationsdiens ^¬ tes, in particular a push-to-talk service or a chat service is configured.

11. The server of claim 8, wherein:

- This simulates an additional communication terminal of the group (G), which causes by means of the connection message (2) establishing the communication connection between the communication terminal (KEG3) and the other kommunikationsbe ^¬ reiten communication terminals (KEGl, KEG2) of the group.

12. The server of claim 8, wherein:

- This is designed to receive a start message (1), with which the communication terminal (KEG3) in the Communication network (Kl, K2) registered for the use of Internet Protocol-based services.

13. The server of claim 8, wherein:

- This is ausgestal ^¬ tet for receiving a start message (1) in the form of the session initiation protocol message "Register".

14. The server of claim 8, wherein:

- This is designed to transmit a connection message (2) in the form of Session Initiation Protocol message "Invite" from ^¬ .