Call control in a telecommunication system

ES 2 177 630 T3

DESCRIPTION

Call control in a telecommunications system.

Field of the invention

The present invention refers to a method for controlling a call in a telecommunications system, comprising a telecommunications network and a first subscriber station and one or more other subscriber stations, said method comprising the stage of maintaining a call in the said subscriber stations participate.

Background of the invention

The establishment of calls involving at least two parties is typical of telecommunications networks. In this way it may happen that a party to the call wants to change the group of subscribers participating in the call or the corresponding telecommunications connection.

Frequently, the subscriber station that has the greatest need to change the group of subscriber stations participating in the call is a dispatcher controlling the telecommunication or call connection, or a fixed control point. This type of situation is typical of PMR networks (PMR = Private Mobile Radiocommunications), in which the distributor communicates with the working groups using different calls, group calls, conference communications and individual calls.

Frequently, in calls of this type, the dispatcher has the need to change the number and group of the subscribers participating in a call. In this way specific reference is made to group calls in which the dispatcher wishes to change the group of subscriber stations participating in them to considerable levels. A group call is a call in which the system, for example, your distributor, or some subscriber station, orders several, at least three, subscriber stations to join the same call by means of a single command. . The groups are formed from the members of a company or some other user organization, and frequently the groups are programmed on a radiotelephone, the central not necessarily knowing which mobile stations belong to which group. Typically, a phone can belong to several groups.

Among the types of calls mentioned above, the only conference communication is the one to which the caller, that is, for example, a person who initiated the call or a dispatcher who supervises the call, can add new subscribers without establishing a call. new. In relation to any type of call, it is not possible to reduce the number of participants in a call without releasing the call totally or partially. Thus, if some subscriber station, for example the dispatcher, wishes to reduce the number of subscriber stations participating in a call, topically a group call, the only possibility for the dispatcher is to release the call on his own. whole. The release of a call causes the problem that the resources used, for example radio communication channels and switching devices, are lost for at least a moment, during which these resources may end up being used in another call if the traffic is intense. Thus, the caller, for example the distributor, cannot communicate regularly with the smallest desired group.

To avoid this drawback, in the solutions of the prior art, the caller must maintain the call with the larger group for an unnecessarily long time, thus wasting resources. On the other hand, some subscriber station, for example the distributor, may want to quickly inform a smaller group of something that the distributor does not want the larger group to know. The implementation of this operation also becomes more difficult if said subscriber station must first release the call and establish a new call, for which resources cannot always be found.

Document EP 604 053, published on June 29, 1994 (subsequent to the priority date claimed by the present application and therefore included within the terms of Article 54 (3) EPC), describes a multi-level conference communication in which the station controlling an individual conference communication can terminate communication with any station included in that conference communication. The user of the controlling station activates the disconnection of the station whose communication is to be terminated by positioning the cursor on the screen of his station in correspondence with the station whose communication is to be terminated and activating the disconnection button. To terminate communication with the station, the controlling station transmits a disconnect message to a switch that supports the connection of the call with the station whose communication is to be terminated. In response to the disconnect message, the switch terminates the link between the controller station and the switch. In addition, the switch transmits a disconnection message to the station to be removed and terminates the link that was used to support the call with the station. Description of the invention

The aim of the present invention is to provide a solution for the problems associated with the solutions of the prior art. More precisely, the aim of the invention is to provide a method and a system by means of which a subscriber station, for example a distributor, participating in a telecommunications connection, can, if it so wishes, change, or more precisely, reduce the group of subscriber stations participating in the call.

This new type of method to control a call in a telecommunications system is achieved with the method of the invention, characterized in that the first subscriber station orders the telecommunications network to eliminate from the call a desired subscriber station or desired group of subscribers. the group call transmitting a kill message to the te2 network

ES 2 177 630 T3 telecommunications, said elimination message comprising the identifier of the subscriber station or group of the group call to be eliminated from the call, and characterized in that the telecommunications network eliminates the desired station from the group call. desired subscriber or group from the group call without interrupting the group call.

The invention also relates to a method for controlling a call in a telecommunications system, comprising a telecommunications network, including a database and a first subscriber station provided with identifiers and one or more other subscriber stations provided with identifiers. , said method comprising the stages of maintaining a call in which said subscriber stations participate and maintaining the identifiers of the subscribers participating in the call in the database of the telecommunications network. This method is characterized by using an add message to add another or other subscribers to the call as well as to remove one or more other subscriber stations from the call, by the order made by the first subscriber station to remove from the call. one or more other subscriber stations by adding to the additional message the identifier of one or more other subscriber stations that already participate in said call and when transmitting the additional message, by comparison, in response to the add message, the identifiers of one or more subscriber stations included in the add message with the identifiers of the subscriber stations participating in the call, these identifiers being maintained in the database, and if the identifiers are the same, interpreting that the add message means that one or more other subscriber stations will be removed from the call, and eliminating from the call those subscriber stations whose identifiers are included in the add-on message. The invention also relates to a method for controlling a call in a telecommunications system, comprising a telecommunications network, which includes a database and a first subscriber station provided with identifiers and one or more other subscriber stations provided with identifiers. , said method comprising the stages of maintaining a call in which said subscriber stations participate and maintaining the identifiers of the subscribers participating in the call in the database of the telecommunications network. This method of the invention is characterized by using an add message to add one or more other subscribers to the call as well as to remove one or more other subscriber stations from the call, by the order made by the first subscriber station to eliminate one or more subscriber stations of the call by adding to the addition message the identifier of one or more other subscriber stations that already participate in said call and by transmitting the addition message, by comparing, in response to the add message, the identifiers of one or more subscriber stations included in the add message with the identifiers of the subscriber stations participating in the call, maintaining these identifiers in the base of data, and if the identifiers are the same, interpreting that the add message means that one or more other subscriber stations will be eliminated from the call, and eliminating from the call those subscriber stations whose identifiers are not included in the add message.

The invention also relates to a telecommunications system, comprising a telecommunications network and a first subscriber station participating in a call and one or more other subscriber stations. The telecommunications system of the invention is characterized in that said telecommunications network comprises means sensitive to the first subscriber station to eliminate from said call one or more other subscriber stations participating in the call.

The invention is based on the idea that a first subscriber station, for example the distributor, instructs the telecommunications network to remove the other desired subscriber stations from the call, and the telecommunications network performs this operation. Subscribers can be removed, for example, in such a way that the first subscriber station transmits a remove message, in response to which the telecommunications network removes the desired subscriber stations from the call.

Even in current systems, a call can be extended by adding new subscribers to it, for example in connection with conference calls. This is achieved in such a way that the caller transmits an add-on message to the telecommunications system, for example, to the PMR radio system, so that, in response to said add message, the system adds the desired subscriber station to the existing call.

To reduce a call, the systems according to the prior art do not comprise a corresponding signaling, but it can be defined or implemented in such a way that the system interprets that the add message means that a desired subscriber station must be removed from the call when the The subscriber station to which the add message refers is already participating in said call. It should be emphasized that the subscriber station to be added can be either an individual subscriber or a group of the group call. Thus, in relation to the reduction, the signaling remains similar compared to the addition.

The advantage of this type of method to control a call in a telecommunications system and of the telecommunications system is that it solves the problems associated with the systems of the prior art, that is, it provides a possibility to reduce the group of subscriber stations. who participate in a call, typically a group call, in the manner desired by the subscriber station controlling the call, the first subscriber station or the distributor.

The invention has the advantage that, by means of it, a subscriber station, for example the distributor, can quickly direct3

ES 2 177 630 T3 even a large group call to a small reduced group in operations that require high speed. The first subscriber station, which controls the call, can be sure that the reduction of the call will be successful, without interrupting the call, since the resources needed by the smaller group are already reserved for the original larger group, and not it is necessary to separate them in the interim as in the previous technique.

The invention also has the advantage that by means of this new method together with the existing call extension methods, the caller has the possibility to direct, or "focus", his call towards a desired group in a very flexible. In this way, the dispatcher, if he so wishes, can exclude from the call those subscriber stations to which he does not want to give some information intended for a smaller group.

In addition, the invention has the advantage that the method and the system according to it allow rapid communication simultaneously between several groups while at the same time taking advantage of the resources used, for example, radio communication channels. Typically, the distributor, who was using the telephonic radio communication network and who controls several different workgroups in the field of action, benefits from the method.

Brief description of the figures

In the following, the invention will be described in more detail with reference to the accompanying drawings, in which Figure 1 is a schematic representation of the application of the method of the invention in a situation that includes an original call, and a reduced call comprising less subscribers, Figure 2 is a schematic representation of the application of the method of the invention in a situation that includes an original call and an extended call, some subscribers having been eliminated from the original call, in this situation, and new subscribers having been added to the extended call, Figure 3 shows a signaling scheme of a method of the previous technique, in which subscribers are added to a call by In the middle of an addition message, Figure 4 shows a signaling scheme of the method of the invention, wherein the desired subscriber stations have been removed from a call by means of a delete message or add message.

Detailed description of the invention

Regarding the method, it is irrelevant whether the subscriber stations are fixed telephones connected by cable or radiotelephones, and whether the telecommunication network, that is, the telecommunications infrastructure, is a radiocommunication telephone system or a fixed telephone network or some another telecommunications network.

For example, in the MPT radio telephonic system, the elimination message required by the method is produced with an RQS message transmitted on the traffic channel, the IDENT1 field including the number (C) of the subscriber or group to eliminate. Thus, someone who is operating according to the MPT standard should interpret this message as a "delete" message if the subscriber or group whose identifier is C was already participating in the same call with the transmitter of this message.

The implementation of the method can vary freely in terms of the delete message and how the system infrastructure removes redundant subscribers from the call after receiving the delete message.

The MPT signaling mentioned in the example has been defined in the document “MPT 1327, A Signaling Standard for Trunked Private Land Mobile Radio Systems”, January 1988, revised and reprinted in November 1991, particularly in chapter 11.2.1 .

Figure 1 is a schematic representation of the application of the method of the invention in a situation that includes an original call 100, and a reduced call 101 that comprises fewer subscribers. Subscriber stations S are shown in relation to both calls. Furthermore, the figure comprises "a first subscriber station", that is, a subscriber station D, which instructs the telecommunications network to remove a certain group 102 of subscriber stations S from the original call. This first subscriber station is, for example, the dispatcher controlling a group call. When the dispatcher (around which there is a double calculation in Figures 1 and 2) has reduced the group of subscribers participating in the call, the original call 100 is reduced to the reduced call 101, in which fewer stations S than subscriber.

Figure 2 is a schematic representation of the application of the method of the invention in a situation that includes an original call 200, to which a group of subscriber stations S belongs. First, the first subscriber station D, 103 participating in the call, eg the dispatcher, instructs the telecommunications network to remove from the original call 200 a desired group 201 of subscriber stations. In the original call, only the first subscriber station D, 103 and some other subscriber stations are maintained, thus forming a subgroup 203. Next, the first subscriber station transmits an add-on message to the telecommunications network, in response to which the telecommunications network adds more subscriber stations S to subgroup 203, thereby establishing an extended call 202. Thus, in the extended call, some subscribers 201 have been removed from the original call, and new subscribers have been added to the extended call 202.

Figure 3 shows a signaling scheme of a method of the previous technique, in which subscribers are added to a call by means of an add message. In Figure 3, an A-subscriber 300, D, that is, the first subscriber station, for example, the distributor, transmits an additional message 301 towards the telecommunications network 306, Infra, more exactly the infrastructure, which can understand, for example4

ES 2 177 630 T3 example, base stations and switching centers of the radiocommunication telephone system, or transmission devices and exchanges of the telephone network. The add message 301 includes the identifier C of the subscriber, subscribers, or group of the group call to be added to the call. After this, the telecommunications network transmits a call message 302 to the subscribers 303, subscriber-C, whose identifiers were included in the additional message 301. When the called subscribers receive the call messages 302, they transmit a receipt confirmation message to the Infra infrastructure, which also transmits a receipt confirmation message 305 to the A-subscriber D. At the same time, C-subscribers join the call, and are assigned the necessary resources, such as radio channels, transmission links, and switching capacity. After receiving the acknowledgment message 305, the A-subscriber 300, D knows that the additional message 301 transmitted by him has reached its destination and that the subscribers who had transmitted their acknowledgment message 304 to the system Infra have joined the call.

Figure 4 shows a signaling scheme of the method of the invention, in which the desired subscriber stations have been removed from a call by means of a delete message or add message. In Figure 4, a subscriber-A, 300, D, that is, the first subscriber station, for example, the distributor, transmits a delete message 401 towards the telecommunications network Infra. The delete message 401 includes the identifier C of the subscriber, subscribers or group of the group call to be removed from the existing call. After this, the telecommunications network 306, Infra, transmits a delete or release message 402 to the subscribers 403, C-subscriber, whose C identifiers were included in the delete message 401. When the subscribers 403 to be deleted receive the delete or release messages 402, they transmit a reception confirmation message 404 towards the Infra infrastructure, which also transmits a reception confirmation message 405 towards the A-subscriber D.

It should be noted that in one embodiment of the invention, the delete message may be exactly similar to the add message, but the telecommunications network reacts to it in a new and innovative way, i.e. the network or infrastructure compares the identifier of the subscriber stations or group call included in the adition message with the identifiers of the subscribers or group calls that participate in the call to which subscriber-A, the transmitter of the message, belongs in addition. Thus, as a consequence of this comparison, if the identifiers included in the additional message were the same as the identifiers of the subscribers or group calls participating in the call to which subscriber-A belongs, the transmitter of the message In addition, the telecommunications network interprets this to mean that the station

Subscriber D, who had transmitted the add message, wishes to remove the subscribers mentioned in the add message from the call.

In a third embodiment of the invention, the identifiers C of the subscriber stations and the groups of the group calls included in the add-on message 401 are compared with the identifiers of the subscriber stations participating in the call located at an infrastructure database 413 in response to the 401 add message on the 306 infrastructure, and if the identifiers are the same, those subscriber stations whose identifiers were not included in said add-on message are removed from the call.

In delete and add messages, the essential element of information is the subscriber or group number C to which the message operation refers. Other messages, ie, call message 302, release message 402, and acknowledge message 404, are existing system-specific messages for calling and releasing a subscriber or group and for expressing acknowledgments of receipt.

The telecommunications network according to the invention, the telecommunications infrastructure 306, Infra, comprises means 411 that respond to the first subscriber station 300, that is, the subscriber-A, or, for example, the distributor or supervisor of the system, to remove one or more different subscriber stations (Figure 1, 102) participating in the call from the call. This removal is done in the manner described above by transmitting a release message to the desired subscribers.

In the telecommunications system of the invention, said means 411 responding to the first subscriber station to remove another subscriber station 102 from the call respond to the deletion message 401 transmitted by the first subscriber station.

In the telecommunications system of the invention, the means 411 responding to the first subscriber station to remove another subscriber station from the call responds to the add-on message transmitted by the first subscriber station. This refers to the second embodiment of the invention.

The telecommunications system of the invention comprises comparison means 412 that respond to the add message 301 transmitted by the first subscriber station to compare the identifier C of the subscriber station included in the add message 301 with the identifiers of the stations. subscribers participating in the call stored in the database 413 of the telecommunications network 306, and to remove one or more different subscriber stations 102 from the call based on said comparison.

The figures and the description referring to them are only intended to illustrate the idea of ​​the invention. In relation to its details, the method of the invention for controlling a call in a telecommunications system and a telecommunications system may vary within the scope of the claims. Although the invention has just been described mainly in relation to

ES 2 177 630 T3 a mobile communication system or radiocommunication telephone system, the invention can also be used in other types of telecommunication systems, such as conventional telephone networks or intelligent network (IN) applications of said networks.