WO2004016025A2

WO2004016025A2 - Telecommunication system, server and terminal for said system

Info

Publication number: WO2004016025A2
Application number: PCT/FR2003/050018
Authority: WO
Inventors: Jacques Bresson
Original assignee: So Near
Priority date: 2002-08-02
Filing date: 2003-07-21
Publication date: 2004-02-19
Also published as: FR2843262A1; WO2004016025A3; AU2003274296A1; FR2843262B1

Abstract

The invention relates to a telecommunication system, especially a mobile telephone system. In addition to the traditional communication channel, said system comprises a separated channel (18, 24) for communication with a server (28), so that the terminals (10) can request services, in particular telephone services, which are provided via said server. The present system is arranged such that a terminal can request information, on the availability of a terminal called or to be called, from the server prior to the call signalling, whereby the request is transmitted by means of the channel separated from the call signalling channel. For example, the channel for communication with said server has at least one channel included in the group consisting of a GPRS channel (18), a SMS channel (24), a UMTS channel and a CDMA channel.

Description

TELECOMMO ICATION SYSTEM, AND SERVER AND TERMINAL THEREFOR

SYSTEM

The invention relates to a mobile telephone telecommunications system as well as to a server, a terminal and a terminal accessory of such a telecommunications system. A mobile telephone network, such as, for example, the GSM network, comprises a radio access network composed of cells, of limited geographical areas and within each of which is located a base station through from which all mobile communications in this cell pass, the base stations are linked to a core network.

These cellular mobile networks have been developed to offer mainly basic telephone service and their architecture is similar to that of conventional fixed telephone networks. In particular, signaling is that which corresponds to the CCITT SS7 standard between network nodes both for establishing calls and for accessing additional services. An essential organ of a mobile network is an MSC / VLR switch which is a specialized telephone switch for mobile networks for access to the core of the network, combined with a database containing all the network, combined with a database containing all the information relating to mobiles which are managed at a given time by this specialized telephone switch. The name MSC comes from the English expression "Mobile Service Switching Center" and VLR comes from the expression "Visit Location Register".

These switches are complex equipment produced in the form of specific computers with software for processing telephone calls. This software was developed in successive layers and constitutes an increasingly complex and not very evolving set.

The invention results from the observation that the complexity of the SS7 signaling protocol combined with the rigid architecture of specialized switches for mobiles prevents the introduction of certain telephone services which are today available in conventional telephony with PABX or Centrex switches. . The services commonly available in fixed telephony include automatic call back, call screening, group calling, consultation, call transfer, etc. This lack of mobile telephone services is particularly troublesome, since the mobile telephone tends to be used systematically in place of the fixed telephone.

The invention allows the introduction of functions in mobile telephony without modifications to the corresponding network.

The telecommunications system according to the invention is characterized in that it comprises a server connectable to the mobile via a communication channel distinct from the telephone signaling channel exchanged with the specialized switch, this server comprising means to provide services to terminals. The communication channel for connection to the server is physically or logically distinct from the telephone signaling channel.

We therefore offer, in a particularly simple way, the possibility of providing various services in mobile telephony. For example, the server includes means for memorizing at least the state of each mobile in order to communicate this state to a calling mobile.

With this system, before the initiation of a telephone call, the availability of the requested terminal is checked, which allows the caller not to initiate the call itself and, thus, to avoid connecting to the messaging system. voice of the called party with, in general, the corresponding charge.

In addition, since calls between mobiles are not carried out systematically, the invention makes it possible to minimize the congestion of the network.

In one embodiment, the server also includes means for proposing to the caller an automatic call back to the called party.

Other actions or services offered to the user are, for example, charging on demand, or filtering services in the event that subscribers are grouped.

According to one embodiment, the server is connected to the mobile via an SMS (Short Message Service) communication channel and / or by a GPRS type A or B channel, and / or by a UMTS channel, and / or by a CDMA channel.

It will be recalled here that the SMS channel passes through the core of the network but uses signaling distinct from call signaling, such as GSM signaling.

It is also recalled that the GPRS (General Packet Radio Service) channel makes it possible to connect mobile telephone networks to the Internet, or, more generally, to networks using the IP protocol. It is preferable that the telecommunications system is such that the mobiles have the possibility of accessing the server both by SMS and by GPRS. In this case, the terminals which do not have the GPRS channel communicate with the server via the SMS channel. Likewise, class B GPRS terminals with only one GPRS channel will use the SMS channel to communicate with the service server when the GPRS channel is already used for data transfer or for telephone communication.

When planning the double SMS and GPRS path, it is preferable to give priority to the GPRS path because the delivery of messages by the SMS channel takes more time, on average 10 seconds.

In general, we prefer to connect to the service server via an IP network. Thus, in addition to GPRS and UMTS, it is possible to use a radio access network of the "Wireless Lan" type such as one of those corresponding to the standards IEEE 802.11b, IEEE 802.11a, IEEE.802. g and "Blue Tooth". It is also possible to use a fixed broadband IP network of ADSL, SDSL or VDSL, FTTB, FTTH and HFC type. It is recalled here that the FTTP and FTTH networks are fiber optic networks to buildings or to apartments while the HFC network is a mixed network of coaxial cable and fibers.

The invention relates not only to a telecommunications system but also to each of its elements considered individually, namely the service server and the mobile terminal. It also relates to a method of providing services in a mobile telecommunications system as well as the associated signals.

Thus, a terminal according to the invention comprises a means for communicating with a service server by means of at least one signaling channel distinct from the calling channel in order to request and obtain services by this server.

For example, prior to a call proper, the terminal can determine the state of the called terminal.

The means of communication with the server is, for example, in software form. It can be found either in the terminal itself or in a SIM card.

The invention also extends to a SIM card comprising such a means. A service server according to the invention comprises means for its connection to mobile terminals by means of a channel separate from call signaling.

This server preferably includes means for recording the state of each mobile.

The service server comprises, in one embodiment, a semi-permanent database for identifying, for example by their telephone numbers, the users who can have access to the services. By users, here is meant either individual terminals, or sets of terminals forming, for example, a group of users. The server also includes a dynamic database in which is noted at least (in an example) the state of the mobile, that is to say in particular if the mobile is available, busy or unreachable, that is to say - say that it is no longer under cover or that it is extinct. This dynamic data may also include data relating to additional services such as automatic call back or filtering. They can also include dynamic service management parameters for a set of users, such as grouped line management pointers. For example, for a group of users, the service makes it possible to determine the terminal to which the next call will be presented.

For updating the dynamic database, the server includes means for receiving the connection, disconnection and location information transmitted by the mobiles.

When the server manages groups of subscribers, it includes means for memorizing the services to which the members of the group are entitled and for updating these services, in particular activating and deactivating them.

In one embodiment, each mobile is assigned an IP address. In this case, the server must know the correspondence between the mobile number and this IP address. Thus, the invention relates, in general, to a telecommunications system, in particular a mobile telephone system, which is characterized in that it comprises, in addition to the usual signaling channel, a separate channel for communicating with a server so that the terminals can make use of services provided via the server, this system being such that a terminal can send, prior to call signaling, a request to the server for information on the availability of a terminal called or to be called, this request being transmitted via the channel distinct from the call signaling channel.

The communication channel with the server comprises, for example, at least one channel included in the group comprising: a GPRS channel, an SMS channel, a UMTS channel and a CDMA channel.

The communication channel with the server can also include an IP channel.

When the system includes, for communication with the server, an SMS channel and a GPRS channel, the GPRS channel preferably has priority over the SMS channel.

In one embodiment, the server comprises means for coordinating services between terminals by sending them commands, by proposing actions to them and by receiving from these terminals information such as their state of occupation or reachability.

The server comprises, according to one embodiment, means for memorizing groupings of terminals and means for enabling, in each grouping, at least one of the following functions: diversion of a call from a filtered terminal to a terminal filter, call pickup and choice of terminal to connect for an incoming call intended for grouping.

The invention also relates to a server for a telecommunications system, in particular a mobile telephone system, which is characterized in that it comprises an input connectable to terminals of the system via a separate channel from call signaling so as to provide services to the terminals, means for receiving information on the busy or reachable state of the terminals and means for transmitting this information to calling terminals, this information being transmitted to the terminals callers prior to call signaling emitted by these latter terminals via said channel separate from call signaling.

The server may include means for storing data relating to groupings of terminals. In this case, the data relating to the grouped terminals includes, for example, data relating to the filter terminals and to the filtered terminals and line associations.

The server comprises, in one embodiment, means for temporarily storing service indicators relating to terminals. The service indicators are, for example, included in the group comprising: automatic call back, filtering, charging to the called party, unavailability messages, call by name and group call.

The connection channel to the terminals comprises, for example, at least one channel included in the group comprising: an SMS channel, a GPRS channel, a UMTS channel and a CDMA channel. In this case, the server can be connectable to the terminals via an IP channel connected to said connection channel.

In one embodiment, the server comprises means for transmitting to a terminal called when it was busy or not reachable, information on a terminal having called it during its unavailability state.

The invention also relates to a terminal, in particular of the mobile type, for a telecommunications system, characterized in that it comprises means for receiving via a channel distinct from the call signaling channel, at least a service provided by a server and, prior to call signaling, a request to the server for information on the occupancy or reachability status of a terminal called or to be called, this request being transmitted via said channel separate from the call signaling channel.

The terminal may include means for transmitting to the server, by the same channel separate from the call signaling channel, a signal representative of its state.

The communication channel with the server is, for example, included in the group comprising a GPRS channel, an SMS channel, a UMTS channel and a CDMA channel.

In one embodiment, the terminal includes means for automatically confirming the call when it receives the information that the called party is available.

The terminal comprises, in one embodiment, a means for requesting an automatic call back to the called terminal to the server when the latter is not available. In this case, the terminal may include a means for transmitting to the server information prior to its unavailability, this information preferably comprising a message relating to this unavailability.

According to one embodiment, the terminal comprises means for transmitting to a called terminal a request for charging to this called party which is transmissible to the latter via the server. In this case, the terminal may include means for transmitting, via the server, to a calling terminal, information on refusal of charging for this call.

In one example, the terminal includes means for transmitting call diversion data to the server to another terminal.

In one embodiment, the terminal includes means for receiving, preferably through the server, an indication that incoming calls intended for another terminal are directed to this terminal which then constitutes a filter for the other terminal, a means for, during an incoming call, inform the other terminal, said to be filtered, that a call is intended for it, and means for temporarily eliminating the filtering in order to connect the incoming call to the filtered terminal.

The means for communicating with the server can be incorporated in a removable element, such as a SIM card.

The invention also relates to an accessory for a mobile telephone terminal, in particular a SIM card, which is characterized in that it includes a means so that the terminal can be connected to a service provider server via a channel. distinct from the call signaling channel and a means so that the terminal can send, prior to the call signaling, a request to the server for information on the busy or reachability status of a called terminal or to be called, this request being transmitted via said channel distinct from the call signaling channel.

In one embodiment, the accessory of the SIM card type is such that it includes a software product making it possible to receive and manage applications independent of each other.

It is thus possible to install new services without altering the services previously installed on the card.

This arrangement provides a significant advantage over conventional mobile telephony systems. When you install a new service in such a classic system, you have to make changes in the core of the network, replace the SIM cards of subscribers who must benefit from the new service and carry out validation and pilot network phases. which are long and expensive. It is recalled here that a pilot network is an implementation of a network, in real size, with a representative sample of users. Instead of replacing SIM cards, it is also possible, in known networks, to download modified SIM cards by SMS. But this operation is long and unreliable because downloading the content of a SIM card requires several kilobytes while an SMS message only authorizes about 140 bytes. Thus, in current networks, the modification of services is only carried out when it is substantial, with the addition of an important service.

It can therefore be seen that the arrangement of the invention according to which it is possible, in the mobile SIM card, to receive and manage applications independent of each other, allows the introduction without difficulty of new services, of any type.

Although this arrangement of the invention preferably applies to a terminal which can be connected to a server providing services via a channel separate from the call signaling channel, it also applies to services that can be installed through the core of the network. In this case, the arrangement described makes it possible to easily produce a prototype, without prior modification of the core of the network, in order to validate the new services. In other words, with a SIM card in which one can receive and manage applications independent of each other, one can carry out tests, both technical and commercial, in order to verify the interest of the new services and to test them to remedy their possible shortcomings. In other words, with a conventional network, it is not essential for all of the SIM cards of the mobiles to be such that each SIM card can manage applications independent of each other, but this arrangement can be used in test mobiles.

In one embodiment, in order to reduce the amount of information to be loaded into the SIM card, the latter contains a code interpreter. If the Forth language is used, then the compaction is of the order of 10 for the messages transmitted to the mobile. In this case, the applications are downloaded to the SIM card from a server (which may be separate from the service provider server) comprising a processor which makes it possible to produce an interpretable code, i.e. a list of index representing words to be saved in a basic dictionary in memory of the SIM card.

Thus, the SIM card comprises, in this example, a basic dictionary and, if necessary, memories for additional dictionaries.

Other characteristics and advantages of the invention will appear with the description of some of its embodiments, this being carried out with reference to the appended drawings in which:

Figure 1 is a diagram of a telecommunications network according to the invention, and Figure 2 shows an example of downloading services according to the invention.

In the example shown in FIG. 1, a telecommunications network with mobile terminals 10 is provided. Each mobile terminal communicates with the network by means of a base station 12 (or "node B" in the case of the UMTS system). ) being in a cell. Each base station is controlled by a control station 14. The base station is in communication with the core of the network by means of a specialized telephone switch MSC 16 which makes it possible to communicate with one another the various fixed or mobile terminals . The signaling attached to each communication, such as the GSM standard signaling, passes through the switch 16.

The SMS data also pass through the switch 16.

Furthermore, each mobile 10 can also be put in contact with an IP network via a GPRS channel 18. To this end, in a manner known per se, the terminal 10 communicates with a specialized router 20 or SGSN (" GPRS service Support Node ") which is linked to another router 22 connected to one or more IP or X25 data networks. This router 22 is sometimes called GGSN (" Gateway GPRS Support Node ").

When the terminal 10 wants to enter into communication with another terminal (not shown), it transmits a call signal, for example according to the GSM standard, and this signal is transmitted to the switch 16 which retransmits the call to the called terminal.

The invention also makes use of another signaling channel which is, in the example, constituted by the SMS channel 24 and / or the GPRS channel 18.

This or these other signaling channel (s) is (are) connected to a server 28 via an IP network. Thus, as shown in FIG. 1, in the example the channel 18 is connected to the server 28 via the Internet network 30.

The service server 28 is also connected to the SMS channel 24 by means of an SMSC server 32 connected to the GSM network by means of a switch 34 of the same type as switch 16. This server makes it possible to send and receive SMS messages.

Instead of the server 32, one can provide a facilitator of access to an operator network (sometimes called "broker").

The server 28 is intended to store the state of each terminal and to transmit this state to the calling terminals.

In addition, in the example, the server provides other services separate from telephone switching as described below.

The server 28 being connected to an IP network, it can be controlled by an operator separate from the mobile operator, for example by an MVNO operator, that is to say an operator with a radio network infrastructure which its own ("Mobile Virtual Network Operator").

The simplest service provided by the server 28 which can be reached via channel 24 and / or 18 is the following: when the terminal 10 calls another terminal, software located in this terminal or in its SIM card communicates with the server 28, prior to the call itself, so as to determine the state of the called terminal. By "state" of the called terminal means that it can communicate, that it is busy, that it is out of coverage or that it is switched off or that it refuses calls.

Thus, the server 28 includes means for communicating, also by the channel 18 and / or 24, with the called terminals in order to determine their state. Once this information has been obtained by the server, the latter transmits it to the calling mobile and the latter can then effectively call, by conventional call signaling, the terminal which it wishes to reach.

This operation is illustrated by the table below.

Simplest case (B is free)

Mobile A Subscriber A Server Subscriber B Mobile B

B free

Call B requested

Request state B Request state B

B free

B free state

^••

Call A -> B

Logout Logout

A free B free Each terminal comprises, in the terminal itself or in its SIM card, means, in particular software, for, prior to the actual call, connect to the server 28 in order to check the state of the called terminal. Likewise, each terminal includes means for automatically responding to a status request which is sent to it by the server 28.

It should be noted that, preferably, the information on the state of the called party is supplied, for example on a screen, to the terminal of the calling party and, in this case, the calling party has manual access to the possibility to confirm the call, if the called party is free, or to abandon the call if it is busy or out of coverage, or, generally, not reachable. In any case in this case, compared to current systems, the service offered does not involve the occupation of the mobile telephone network and makes it possible to avoid automatically connecting, by a tariff link, to the messaging of the called party.

The system according to the invention also allows an automatic call back when the called party is busy as shown in the table above:

Automatic callback on busy (B busy)

It appears from this last table that the caller has on his terminal a menu allowing him to choose the automatic callback service or to refuse this service when the mobile “called B is in the busy state or not reachable. Similarly, when the called party becomes reachable, the caller has the option of confirming the call or not.

The telecommunications system also makes it possible to carry out an automatic call back when the communication is interrupted in an undesired manner, for example because the caller or the called party comes to be in a situation of non coverage. This service is represented by the table below: Automatic call back on released call (B becomes out of coverage)

Mobile A Subscriber A Server Subscriber B Mobile B

Logout Logout

Mobile without coverage

At free

W

Automatic callback (AR) on B

<>

If 0, request RA on B

Mobile under cover

B reachable A

As a variant, automatic callback is offered to subscriber B returned under cover.

The telecommunication system also makes it possible, according to another embodiment, to notify a terminal that it has been called while it was busy and, optionally, to provide the called party with the number of the calling party, as illustrated by the table below:

Call notification A during busy B

This call notification is particularly useful when the caller has not chosen the automatic callback option.

Another service which the telecommunication system considered in the example can still provide is to allow each mobile to refuse communications and to supply this information to the server 28 which stores it in memory and communicates it to all the callers.

This service is represented by the table below: Do Not Disturb (NPD)

Mobile A Subscriber A Server Subscriber B Mobile B

B NPD state (with associated message)

Call B requested

<

Request status B

B NPD state (with associated message)

Message display with acknowledgment of receipt A> -

NDP cancellation

The associated message recorded in the server is, for example, the period of unavailability and, possibly, the person to contact during this period.

On this last table we observe that, when the calling subscriber A seeks to join the called party B, it is not necessary to establish a communication between the server and the mobile called B since the server already has the state 1 'called in memory.

According to yet another embodiment, the telecommunication system makes it possible to charge the called party, that is to say to charge the call for the call by the subscriber of the called number if the latter accepts it.

This service is represented by the table below: Charging on demand (A -> B replaced by B -> A)

Charging to the called party is thus carried out in the following manner: the caller A has in his menu a possibility of charging to the called party, that is to say to the number called. In this case this request is transmitted by the server and if the called party accepts, it is the latter who initiates the call. If he refuses, the refusal is communicated to the caller via the secondary SMS or GPRS channel.

In one embodiment of the invention, group telephone services are also provided.

In the example, n filter terminals and p filtered terminals are provided. Incoming calls for filtered terminals are forwarded to the terminal, or to terminals, corresponding filter (s). To this end, the server 28 has permanence of the information relating to the filter and filtered states of the _^ terminals. This information is transmitted by the filter terminals. For this purpose the server periodically interrogates the filter terminals. If at the time of this interrogation the filter terminal is busy, or, in general, not reachable, the update is deferred until the availability of this terminal.

Thus each terminal has a means for unconditionally forwarding incoming calls to a specific filter set. This filtraqe and this reference can be activated and deactivated by a single maneuver of the filtered terminal through, for example, a terminal menu.

It should be noted that the calling terminal (mobile or fixed) is not necessarily connected or connectable to the server 28.

The group telephony service thus works as follows:

An incoming call to a filtered terminal is directed to the corresponding filter set. The status of the filtered terminal is displayed on the screen of the filter terminal in order to constitute an indication or a reminder for the user of this filter terminal.

This filter terminal thus has a button for placing incoming calls on hold in order to perform the following operations:

If the filter terminal is free, it is offered a double call to the filtered terminal on its screen. However, to allow direct communication between the caller and the screened called party, momentarily delete the forwarding. To this end, the double call from the filter to the filtered is automatically preceded by a signal in the form of an SMS message or a message on the GPRS channel, via the server 28.

The return of the filtered to the filter is reactivated automatically immediately after establishment of the call. If the user of the filtered terminal accepts the incoming call, the user of the filtered terminal picks up this incoming call and becomes free of it.

If the filtered user refuses the call then the filtered user takes the incoming call, for example to write down a message or an appointment.

As a variant, the filtered terminal forwards all of its incoming calls to the filter, except for calls coming from the filter terminal itself. In this case, the delete removal action is useless.

In another variant, instead of temporarily removing the forwarding, the filter terminal triggers the sending of a message to the filtered terminal to prevent it from calling the filter terminal.

In all cases, in this example, the contact details of the caller are transmitted to the filtered terminal to allow him to make the call by simple confirmation.

If the filtered terminal is busy, an SMS message is automatically sent from the filter terminal to the filtered terminal via the server 28, as well as the display of a message on the screen of the filtered terminal to inform it to call back. the filter terminal. This last message is preferably displayed at the end of the current call so as not to disturb the user during a call.

In this case, if the user of the filtered terminal decides to take the call, he can put the engaged call (that is to say the previous call) on hold and call the filter terminal.

If the user of the filtered terminal ignores the message indicating a new incoming call while it is already engaged, or if the user decides after calling the filter terminal not to take the call, the user of the filter terminal manages then directly following the incoming call.

The table below is an example of exchanges following an incoming call. In this table, A represents the incoming call, B the filtered and C the filter.

Group telephony: Exchanges following an incoming call

(B free)

Mobile C Subscriber C Server Subscriber B Mobile B

Incoming call from A with display of B status

^ SMS message with A parameters

Delayed sending C

C returns to A and releases the call

* The message must arrive before the transfer of the call from A to B to allow the temporary cancellation of the forwarding.

The table below represents exchanges following an incoming call while the filtered mobile B is busy. Group telephony: Exchanges following an incoming call

(B busy)

Mobile C Subscriber C Server Subscriber B Mobile B

Incoming call A with display of B status

• <

SMS message with A parameters

SMS message with A parameters and call waiting display

C occupied by B

Call B -> C with call waiting on hold

B free

B occupied by A Call B -> A

C returns to A and releases the call immediately or when the BC call is established

Another service which can be provided by the server 28 is that the latter contains a directory by name usable by mobiles. In this case, the terminals can dial a called name and the server translates this name into a corresponding number.

If several subscribers have the same name, a selection is proposed.

The invention also allows group calls using the server 28. In this case, a set of terminals has the same call number and the server chooses the terminal to call according to one or more predetermined criteria (s) ( s) such as free terminal whose last request is the oldest.

It is also possible that the server sends a message to all of the group's terminals informing them of an incoming call for the group and this call will be transferred to the first terminal that answered.

In one example, a subscriber belongs to several user groups with the same terminal and the same number.

Although in the examples described, the channel intended to communicate with the server is a physically separate channel from the signaling channel, it goes without saying that this communication channel with the server can only be logically distinct from the signaling channel, c that is, use the same physical channel.

Furthermore, it can be noted that in general, an interaction is called for between the information transmitted by the connection path to the server and the signaling information.

In a first example of such an interaction, we consider a call made by a subscriber. The number called is communicated to the mobile SIM card and the latter orders a test of the status of the mobile called in the following sequence: the SIM card temporarily cancels the requested call; this SIM card sends a requested status request message to the server 28, and if the response is that the requested number is free, the previously requested call is restored.

Thus, in this case, the interaction between the two channels is initiated by the subscriber.

In a second example, the interaction between the two channels is initialized by a network event. To fix the ideas, we consider an incoming call to a filtering set and intended for a filtered set. It is recalled here that the filtering was carried out by means of a command from the filtered station which was communicated to the server 28. The incoming call message is communicated to the SIM card of the filtering set and the latter offers the user a double call to the filtered set or the sending of a message if the filtered set is busy. In this case, the operation is as follows:

Reception by the SIM card of the external extension filtering station. The filtering station's SIM card offers to call the filtered extension and put the outside call on hold. If the user of the filtering station responds positively, the SIM card makes the call and puts it on hold.

The operation can also be initiated by the server. As an example of such a situation, consider the processing of an automatic callback. When the mobile to be automatically called back has signaled to the server • its return to availability, the sequence of operations is as follows:

The server sends a message to the waiting calling mobile. This information received from the server is supplied to the SIM card of the caller who offers the callback and, in the event of a positive response, the SIM card resets the call.

The interaction between the two channels can also be independent of the calls. Thus, in the case where the server systematically receives all the changes in the state of the mobile, the server includes means for offering services conditioned by the state of this mobile.

Finally, the interaction can be determined by subscriber commands conditioning the calls. Thus, the activation, by the subscriber, of a service such as filtering or charging of the called party constitutes a command which is communicated to the server in order to allow the latter to offer the corresponding services during calls to come.

Although the invention has been described with reference to a telecommunications system by mobile telephony, it also applies to fixed telephony, that is to say that the server 28 can be used for telephony services fixed, the mobile terminals 10 being able to be replaced by fixed telephony terminals.

We will now describe in relation to FIG. 2, an embodiment of the invention which allows easy installation of new services.

The mobile phone SIM card includes a software product that can receive and manage applications that are independent of each other. This software product called "core" makes it possible to enrich the services offered to the mobile phone user without having to change their SIM card.

In addition, the software product can execute the applications by interpreting a code. Preferably, this software product uses the Forth language which presents, in a manner known per se, self-enrichment characteristics. With this arrangement, the amount of information to be downloaded to the SIM card is reduced. It can be transmitted by a limited number of SMS messages, for example three or four.

Although the Forth language is known, it is recalled that the Forth system constitutes, on the one hand, an extensible lanqage and, on the other hand, an interactive development process.

The method is based on a two-stack virtual machine, namely a data stack and a results stack.

The evaluation of the data is carried out on the data stack using, according to a first characteristic, the reverse Polish notation (RPN).

For example, the following sequence entered on the keyboard:

3 4 + 5 * interactively puts the value 3 in the stack, adds 4, calculates the sum and replaces them in the stack with the result 7, in turn multiplied by 5, the stack containing the final result 35.

The RPN 3 4 + 5 * sequence corresponds to (3 + 4) * 5 according to the most usual notation commonly taught. A second characteristic of the process. Forth is that it uses RPN notation to achieve simple syntax and good modularity.

Forth programming uses subroutines and factorization.

The example below defines a function (called a word in Forth) which unpacks a and b, calculates the sum of two squares and puts the result c on the stack:

In this example, DUP duplicates the variable at the top of the stack, S AP smooths it under the one below and * is the multiplication operator.

: SUM-OF-SQUARES (a b - c) DUP * SWAP DUP * +;

If we previously defined the function:

: SQUARED (n - nsquared) DUP *; we can then define the SUM-OF-SQUARED function as follows:

: SUM-OF-SQUARES (a b - c) SQUARED SWAP SQUARED +;

Writing a program in Forth amounts to enriching the language with all the functions required to implement the application.

A Forth system uses two interpreters:

- a text interpreter which makes it possible to create a new entry in the dictionary and to replace all the words contained in the entry flow by addresses of word pointer, and

- an address interpreter which makes it possible to read the addresses and to execute the corresponding words while managing the two stacks of data and result.

FIG. 2 shows a pre-processor, or processor, 40 arranged in a server which can be distinct from the server 28. This processor makes it possible to write and generate interpretable codes, that is to say the list indexes of words saved in a basic dictionary or in an additional dictionary in the mobile. Thus, in the SIM card of the mobile telephone 42, an interpreter is provided comprising an event table 44 connected to an assembly 46 having an input 48 intended to receive words coming from the processor 40. The block 46 also receives the data supplied by the event table 44. This block 46 makes it possible to initialize a new service in combination with a basic dictionary 50 containing the words and the corresponding executable instructions. To this dictionary 50 are added, in the example, two additional dictionaries 52, 54 which can be downloaded. In other words, the Forth system makes it possible to load new words which can then be executable for future services.

Thus, the processor 40 sends non-executable codes, such as scripts, which are supplied to the interpreter of the SIM cards.

Claims

1. A telecommunications system, in particular a mobile telephone system, comprising, in addition to the usual signaling channel, a separate channel for communicating with a server so that the terminals can use the services provided through the server, this system being such that a terminal can send, prior to call signaling, a request to the server for information on the availability of a called or calling terminal, this request being transmitted via the channel separate from the channel call signaling.

2. System according to claim 1 characterized in that the communication channel with the server comprises at least one channel included in the group comprising: a GPRS channel (18), an SMS channel (24), a UMTS channel and a CDMA channel .

3. System according to claim 2 characterized in that the communication channel with the server (28) further comprises an IP channel.

4. System according to claim 2 or 3 characterized in that it comprises for communication with the server an SMS channel (24) and a GPRS channel (18), the GPRS channel having priority over the SMS channel.

5. System according to one of claims 1 to 4, characterized in that the server comprises means for coordinating services between terminals by sending them commands, by proposing actions to them and by receiving information from these terminals.

6. System according to one of claims 1 to 5 characterized in that the server (28) comprises means for storing groups of terminals and means for enabling, in each grouping, at least one of the following functions: diversion a call from a filtered terminal to a filter terminal, call pickup and choice of terminal to connect for an incoming call intended for grouping.

7. Server for telecommunication system, in particular for mobile telephony, characterized in that it comprises an input connectable to terminals of the system by means of a separate channel from call signaling so as to provide services to terminals, means for receiving information on the state of occupation or reachability of the terminals, and means for transmitting this information to calling terminals, this information being transmitted to the calling terminals prior to the signaling of the call sent by these last terminals through said separate channel of call signaling.

8. Server according to claim 7, characterized in that it comprises means for storing data relating to groupings of terminals.

9. Server according to claim 8, characterized in that the data relating to the grouped terminals comprises data relating to the filter terminals and to the filtered terminals and line associations.

10. Server according to one of claims 7 to 9, characterized in that it comprises means for temporarily storing service indicators relating to terminals.

11. Server according to claim 10, characterized in that the service indicators are included in the group comprising: automatic call back, filtering, charging to the called party, unavailability messages, call by name and 1 group call.

12. Server according to one of claims 7 to 11, characterized in that the connection channel to the terminals comprises at least one channel included in the group comprising: an SMS channel, a GPRS channel, a UMTS channel and a CDMA channel.

13. Server according to claim 12, characterized in that it is connectable to the terminals via an IP channel connected to said connection channel.

14. Server according to one of claims 10 to 13, characterized in that it comprises means for transmitting to a terminal called when it was busy or not reachable, information on a terminal 1 'having called during its state of unavailability.

15. Terminal, in particular of the mobile type, for a telecommunications system characterized in that it comprises a means for receiving via a channel distinct from the call signaling channel, at least one service provided by a server. and, prior to call signaling, a request to the server for information on the busy or reachable state of a terminal called or to be called, this request being transmitted via said separate channel from the call signaling channel.

16. Terminal according to claim 15, characterized in that it comprises a means for transmitting to the server, by the channel distinct from the call signaling channel, a signal representative of its state.

17. Terminal according to claim 15 or 16, characterized in that the communication channel with the server is included in the group comprising a GPRS channel (18), an SMS channel (24), a UMTS channel and a CDMA channel.

18. Terminal according to claim 15, 16 or 17, characterized in that it comprises a means for automatically confirming the call when it receives the information that the called party is available.

19. Terminal according to one of claims 15 to 18, characterized in that it comprises means for requesting to the server an automatic call back from the called terminal when the latter is not available.

20. Terminal according to claim 19, characterized in that it comprises a means for transmitting to the server a information prior to its unavailability, this information preferably comprising a message relating to this unavailability.

21. Terminal according to one of claims 15 to 20, characterized in that it comprises means for transmitting to a terminal called a charging request to this called party which is transmissible to the latter via the server.

22. Terminal according to claim 21, characterized in that it comprises a means for transmitting, via the server, to a calling terminal an information of refusal of charging for this call.

23. Terminal according to claim 16, characterized in that it comprises a means for transmitting to the server diversion data, to another terminal, calls which are intended for it.

24. Terminal according to one of claims 15 to 23, characterized in that it comprises a means for receiving, preferably via the server, an indication that incoming calls intended for another terminal are directed to this terminal which then constitutes a filter for the other terminal, a means for, during an incoming call, to inform the other terminal, said to be filtered, that a call is intended for it, and a means for temporarily removing the filtering to connect the incoming call to the filtered terminal.

25. Terminal according to one of claims 15 to 24, characterized in that the means for communicating with the server are incorporated in a removable element, such as a SIM card.

26. Accessory for mobile telephone terminal, in particular SIM card, characterized in that it comprises a means so that the terminal can be connected to a service provider server by means of a channel distinct from the signaling channel d call and a means so that the terminal can send, prior to call signaling, a request to the server for information on the busy or reachable state of a terminal called or to be called, this request being transmitted via said channel separate from the call signaling channel.

27. Accessory according to claim 26, characterized in that it comprises means (44, 46, 50) for receiving and managing applications independent of each other in order to allow the provision of new services without having to modify the services previously installed.

28. Accessory according to claim 27, characterized in that the means for receiving and managing applications independently of each other comprises means for receiving a code and an interpreter.

29. Accessory according to claim 28, characterized in that the interpreter comprises a dictionary comprising words corresponding to entry codes and the list of the corresponding instructions.

30. Accessory according to claim 29, characterized in that the interpreter comprises at least one memory for receiving additional words and the corresponding instructions.

31. Accessory according to one of claims 28 to

30, characterized in that the codes are scripts.

32. Accessory according to one of claims 27 to

31, characterized in that the means for receiving the applications independently of one another are a software product in Forth language.