Method of automatic access to a telephone conference and system for carrying out this method

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The invention relates to conference calls or multipoint videoconferences and more particularly to the system for accessing them.

We designate by conference call the possibility for more than 2 people to speak to each other by telephone, we then speak of audio conferencing, or of speaking and seeing each other using videophones or videoconferencing rooms, and we then bet videoconferencing.

When the number of stations concerned is equal to 3, the term 3-party conference is generally used.

This 3-way conference is currently implemented regularly by companies using the facilities offered by their private branch exchanges. But it can also be implemented by a public branch exchange and some fixed or mobile network operators allow their customers to set up this type of conference.

It is generally very easy to use with digital terminals since it suffices to put your correspondent on hold, call the second correspondent, then, when the latter has picked up, press the "conference" button on the terminal to establish a conversation with 3 participants. When the terminal is analog, operations are hardly more complicated by using the numeric keys instead of dedicated keys.

From a 3-party conference, it is often possible to add other participants. However, this process has two main drawbacks: the new participant must be available at the time of the call and the audio quality degrades very quickly with the number of participants because each participant hears all the noise coming from each line.

Consequently, equipment commonly called a conference bridge has been designed to remedy these drawbacks.

The role of this conference bridge is to mix the different channels corresponding to the number of participants while performing a certain number of signal processing operations making it possible to cancel echo phenomena and improve the signal-to-noise ratio to allow listening. comfortable. This equipment also includes all the transmission and signaling functions necessary to connect to the network.

To date, the use of conference bridges, and therefore of the associated conference services, is done as follows.

Participants set a meeting day and time so that they are all available at the same time to join the conference.

One of the participants then reserves a resource on a conference bridge with an operator. The operator gives him a call number as well as, possibly, a secret code that the participants will have to use to join this conference.

Alternatively, one of the participants can have a permanent subscription to a resource on a conference bridge, which allows them to organize a conference at any time. The telephone number, and possibly the access code, were given to him when he took out his subscription.

What has just been described also applies to videoconferencing for which specific conference bridges, and the associated services, have been developed for fixed networks (ISDN, PSTN) as well as for mobile networks (recommendations H. 320, H. 324, H..324M of the UlT-T).

A disadvantage of the technique described above is the number of digits that a user must dial to access the conference call service. Indeed, he must begin by dialing an access number respecting the national numbering, for example 10 digits for France since 2000. And if a secret code is used to prevent the entry of unauthorized participants, he must still dial between 4 and 6 digits.

To restrict the number of numbers to be dialed by the requester, some operators hide a password in the number assigned to the reservation. This then forces the operator to reserve large ranges of specific numbers in relation to the traffic envisaged. Typically 100,000 numbers will be needed for potential traffic of 1,000 simultaneous lanes. This is because a client who tries to reuse the assigned number for a given hour on a given day must have a very low chance of being able to enter a conference from another client during the following days.

A second drawback of the current technique is the link between a given number and a conference bridge. Consequently, the operator cannot change this number to, for example, give it a mnemonic character in connection with a commercial campaign. And, in the event that it has several conference bridges, it can balance the load of these only when it gives the access number to the client, that is to say well before the time of the use: it cannot then react to an unforeseen event such as a breakdown, or to intensive use by subscribed users, to distribute the conferences differently on its various devices.

Another drawback of the current technique relates to the management of access codes. These are allocated for a given number and are therefore linked to a given conference bridge. Modifying the available access codes then requires intervention by the operator on each device.

The object of the present invention is therefore to eliminate the aforementioned drawbacks by decoupling the call number and the secret code of the conference bridge.

Another object of the present invention is to allow the customer to use a secret code that he has chosen from a list of available secret codes, for example for mnemonic reasons.

The aforementioned objects are achieved by using the facilities offered by intelligent networks, within the meaning of ITU-T recommendations Q120x and Q121x, thanks to the implementation of a method of automatic access to a conference call comprising l 'call by a customer of a specific number to participate in a conference call. This call is received and validated by dedicated equipment. Then the dedicated device selects an available conference bridge or the conference bridge on which the conference is already open. And finally it sets up the telephone connection between the client and the selected conference bridge so as to ensure the participation of this client in the conference call.

The aforementioned objects are therefore achieved through the implementation of a system for accessing a conference call comprising a user terminal connected to a telephone network of the intelligent network type, at least one conference bridge connected to this telephone network for ensure the implementation of a conference call, and dedicated equipment belonging to the network, and which, at the request of the user terminal, selects a conference bridge and forwards the call from the user terminal to the conference bridge.

The invention also relates to the software installed on the dedicated equipment which allows the implementation of the method and the system described above.

The invention will be better understood on reading the description and on observing the drawings below, in which,

- Figure 1 shows the architecture of an intelligent network, known from the prior art,

FIG. 2 represents the architecture of an intelligent network to which several conference bridges are connected,

FIG. 3 represents the flowchart for implementing the method according to the invention,

FIG. 4 represents a message according to the INAP User-to-user signaling standard and the extraction of its data in an ISDN message.

The invention using the concepts of the intelligent network as described in the recommendations of the UlT-T cited above, only the elements necessary for the understanding of the invention will be described, with reference to the concepts and definitions included in these recommendations. .

Based on Figure 1., a service. typical of intelligent networks, namely the management of special numbers, is described.

An intelligent network is therefore made up of local access switches (LEC, Local Exchange) which are connected directly to user terminals. If the received call is not a local call, it is directed to the transit switches (SSP, Service Switching Point) which establish a path to the LEC of the called party. The LEC is then responsible for establishing the connection with it.

The "toll-free" service which allows a caller in France to make a free call, or the management of short numbers (with the exception of emergency service numbers (for example 112, European emergency number) which are managed directly by the local access switches LEC), are based on the translation of a 3BPQ logical number having a determined structure (for example 0800 in France for free numbers) into a real destination number. This translation data is part of a table which must be common to all the switches.

When the local access switch receives at 1 from the calling party a call using a logical number 3BPQ, it transfers it at 2 to the transit switch SSP, the logical number 3BPQ not being a local number.

When the number dialed is detected as a 3BPQ number by the SSP, the latter stops all processing relating to this call, and, while reserving the communication channel between the calling party and himself, requests instructions at a point at 3. Service Control Point (SCP). The SCP is a single point which manages the number translation table and to which all the switches are connected. The SCP then searches 4 in its tables for the physical number to which to redirect the call according to the selected logical number, and possibly specific criteria such as the day of the week, the time of day or the place of origin of the call. 'call. Once this number has been found, the SCP indicates at 5 to the SSP that it must establish a connection to such a physical number. The SSP then establishes the communication at 6 in a conventional manner.

The SSP therefore receives the orders from the SCP and executes them.

In this architecture, the SCP therefore plays the role of master while the SSPs are the slaves.

Such a service is listed in the CS-1 set of IUT-T recommendation Q. 1211, in the “number translation services” group.

In some types of services offered by the intelligent network, it may be necessary to establish an interaction with the user. This is the case with services of the “call center” type in which the user is directed to a particular operator according to the type of question to be resolved. To do this, the intelligent network has intelligent peripherals (IP, Intelligent Peripheral) which are used in 7 and 9, under the orders of the SCP, to establish this interaction. Very often these IPs are voice servers.

The SCP sends in this case at 7 a specific command to the intelligent device IP and in parallel requests the SSP to establish communication between the requester and the intelligent device IP.

The intelligent peripheral IP then establishes in 8 a dialogue with the requester in order to collect the necessary parameters.

When the dialogue is completed, the intelligent peripheral IP sends these parameters at 9 to the SCP so that it can determine at 4 the corresponding physical number and returns communication with the calling party to the SSP transit switch.

The SCP sends at 5 the determined physical number to the SSP which will thus be able to establish at 6 the requested communication.

According to a remarkable aspect of the method which is the subject of the invention, the provider of telephone conference services requests from the body responsible for the national numbering plan the allocation of a specific short number which will be used by all persons wishing to access the telephone. a conference call.

As shown in Figure 2, the conference service provider also has a number of conference bridges PC1, PC2 and PC3 connected to the intelligent network and to which specific physical numbers are assigned.

The method which is the subject of the present invention then consists, FIG. 3, by using the mechanisms of the intelligent network as described above, for the SSP, in detecting 2 ′ that the number dialed is a special number, and in transferring 3 then l 'call using the short conference telephone number to the corresponding service hosted by the SCP. Upon receipt of the call, the SCP determines that the number corresponds to the conference call service.

Since the call number, which is of type 3BPQ, corresponds to a set of conference calls, it is necessary for the SCP to determine the requested conference.

To do this, the SCP causes a communication to be established between the requestor and an IP smart device. For example, the SCP provides the smart device with the caller's number.

The intelligent IP peripheral device requests 12 from the caller, for example by voice dialogue, the number of access to the conference in which it wishes to participate.

Remarkably, the intelligent IP peripheral can perform a first validation 13 of the access code dialed, for example on the number of digits composing it, and establish a correction dialogue with the requester in the event of an error.

After detection of a correct code by the intelligent peripheral IP, the latter transmits it 14 to the SCP. The SCP can then perform a second validation 15 to determine whether the code has indeed been allocated. In the event of an error, the SCP sends a command to the intelligent peripheral! P to continue the dialogue and obtain a valid code.

When the access code is correct, communication between the caller and the smart device is interrupted.

During the next step of the method which is the subject of the invention, the SCP determines 17 whether this call corresponds to a new conference to be opened or whether it corresponds to an existing conference, in progress.

If the conference already exists on a conference bridge, the SCP assigns the physical number corresponding to this conference bridge to the call and gives the order 20 to the SSPs to establish the corresponding communication 21, as described above.

If the call corresponds to the opening of a new conference, the SCP polls 18 the conference bridges to determine their availability. As a function of these, and of other parameters set by the operator, the SCP then allocates the conference 19 to a determined conference bridge, therefore to a determined physical number, and gives the order 20 to the SSPs of establish the corresponding communication 21. In parallel, the SCP sends an open conference command to the chosen conference bridge.

In a remarkable variant of the method which is the subject of the invention, the conference bridge sends back to the SCP, in response to the command to open a conference, the number of remaining available channels. The SCP, thus knowing for all the conference bridges the number of available channels, can assign a new conference to a conference bridge without needing to interrogate them specifically.

Communications between the various elements of the intelligent network are governed by the “Intelligent Network Application Protocol” (INAP) signaling standard, the protocols of which are well known to those skilled in the art without it being necessary to describe their implementation in The detail.

A remarkable aspect of the invention relates to the use of the protocol

INAP to allow the SCP to communicate with conference bridges.

It is in fact well known that the INAP protocol is limited to the interior of the intelligent network and that, moreover, the intelligent network communicates with external elements such as subscriber automatic exchanges (PABX) according to the ISDN subscriber signaling ( ITU-T Q. 931).

The method which is the subject of the present invention must therefore convert the messages to the INAP standard into a message to the ISDN standard in order to allow the SCP and the conference bridges to communicate.

Remarkably, the method that is the subject of the present invention uses the “User-to User signaling” coding of the INAP standard to make the SCP communicate with the conference bridges.

The User-to-User Signaling code is used to transfer instructions / data between the intelligent network and an external device such as a private auto-switch or a conference bridge capable of interpreting the ISDN standard.

The instructions given 23, Figure 4, are encapsulated in an INAP message 22 as message data. This has a specific header 24 indicating that it is of the User-to-User Signaling type.

On reception, the LES, which provides the interface with this external equipment, retrieves the data 23 of the INAP User-to-User Signaling message and transmits them to the equipment as an ISDN signaling message 25.

Of course, this change of protocol can be done in reverse. On transmission of a message from the external equipment, the LES will encapsulate it in an INAP User-to-User Signaling message for transfer to the appropriate equipment.

This use of INAP and ISDN signaling cannot be limited to the generality of the invention, a person skilled in the art being able to easily transpose the invention as described below in the context of another signaling, such as CCITT n signaling. ° 7.

It is remarkable to note that, thanks to the method which is the subject of the invention, the supplier can choose to organize all of his conference bridges according to a distributed architecture in which a conference bridge is dedicated to a given zone, with a given physical number or a centralized architecture in which all participant calls are transmitted to a central server which is responsible for welcoming participants on the one hand and distributing traffic to the various conference bridges on the other hand , or a mixed architecture with a set of islands comprising several conference bridges. The invention makes it possible to choose the architecture and to modify it in the best interests of the operator without the customers perceiving any difference, this being hidden by the corresponding service of the SCP, only the configuration of which changes to adapt to the situation. evolution of the architecture of conference bridges.

Another remarkable aspect of the invention is the centralization of the access codes to the conference calls on the database of the SCP.

In the method that is the subject of the invention, the access code is the unique means for singling out a given conference call since all the conferences are called by the users using the same call number. The PCS therefore ensures the management of these access codes and the correspondence between them and the conference calls.

This allows extremely flexible management of these. This centralization of access codes allows the operator to define innovative services for the allocation of these codes, such as for example the choice by the customer of a code from a list of available codes.

Remarkably, the access code can thus be identical to the physical telephone number of the organizer.

Remarkably, the method that is the subject of the present invention makes it possible to use the intelligent peripheral IP to define a mnemonic code. Indeed, by dialing the number of the conference call service, the caller is in dialogue with an intelligent IP peripheral as explained above. The latter can then, for example, offer a choice between access to a conference and the reservation of an access number. If the caller chooses access to a conference, the intelligent peripheral asks him for his access code and the process takes place as described above.

If the calling party chooses number reservation, the intelligent IP device establishes a dialogue with the calling party to choose a valid number. In a particular implementation of the invention, the SCP has previously provided the IP intelligent device with a list of valid and available numbers.