FR2880761A1 - METHOD OF INTERRUPTING THE SPEAKER FROM THE MOMENT OF A GROUP CALL BY ONE OF THE AUDITORS OF THE SAID GROUP CALL - Google Patents

Abstract

The present invention relates to a method of interrupting the speaker of the moment of a group call by one of the listeners of said group call, said group call being established in a mobile telephone network supporting group calls. It is characterized in that it comprises the following steps: a) a step of accessing the mobile station of the requesting listener to a dedicated signaling channel in order to transmit to said network an interrupt request, b) a step processing by the network of said request to decide whether to interrupt said speaker, etc.) a step of interrupting the speaker when said network has decided said interruption.

Description

2880761 1

  The present invention relates to a method of interrupting the speaker of the moment of a group call by one of the listeners of said group call, said group call being established in a mobile telephone network, for example of the GSM (Global System for Mobile communications) supporting group calls.

  In the standardized GSM mobile telephony system at the European Telecommunications Standards Institute (ETSI), a Voice Group Cali Service (VGCS) is available with which it is possible to establish on the radio link a conversation with a predefined group of subscribers in a half duplex mode. A description of this service is given in the recommendations of ETSI referenced respectively GSM 02.68, GSM 03.68 and GSM 04.68. Some paragraphs of GSM Recommendation 04.08 also relate to this service.

  More specifically, this VGCS service allows subscribers who belong to the same predefined group to communicate with each other, after establishing a group call (also called group call: group call), according to the principle of a single speaker ( talker), which is the only one at a given moment during this group call to speak (it is said in a group transmission mode), to several listeners (listener) who can not therefore only listen (they are told in a group receive mode: group receive mode). The mobile station of the speaker uses for this purpose the uplink of a data channel, of the TCH (Traffic Channel) type and subsequently called Group Channel (GCH), but also the downlink (downlink). ) of the same GCH channel while the mobile station of each listener uses only the downstream channel. When no speaker is present in a group, the network warns all the subscribers of the group that the upstream channel of the group channel is free for access and this, by sending specific messages called UPLINK FREE. Conversely, when a speaker is present in a group during a group call, the network notifies the mobile stations of the listeners of the same group that the upstream channel of the group channel GCH is busy and by the sending of messages called UPLINK BUSY. If a subscriber wishes to be a speaker in a group for an already established group call, he makes a request to access the upstream channel of the group channel GCH by sending a specific message UPLINK ACCESS and an access procedure. Uplink access procedure is implemented. Essentially, it consists in allowing this subscriber to become a speaker and 2880761 2 to appropriate the rising channel of the GCH group channel when this upstream channel is free to access and conversely, to reject the access request. of any subscriber when the upstream channel is not open access. For more details on this procedure, reference may be made to Recommendation GSM 04.08 and in particular to Chapters 3.1.2.3, 3.1.2.4, 3.3.1.2, 3.4.15, etc. It should be noted that at any time a speaker can return to the group reception mode and thus release access to the upstream channel.

  The problem posed by this architecture is that, in the current state, it is not possible for a mobile station of a listener to interrupt a speaker during a group call as long as he does not made free access to the upstream channel of the group channel, because the mobile station of the speaker has during this group call, somehow the monopoly of the rising channel of the GCH group channel or a dedicated channel. The only way nowadays for a listener to become the speaker of a group call is to wait until the current speaker has made access to the upstream channel of the group free and then to make an access request. to this rising path to become so speaker.

  There is, therefore, in the system that has been presented above, a need for the establishment of means allowing an auditor to interrupt a speaker to bring him back to the state of auditor and to become himself a speaker.

  The present invention thus relates to a method of interrupting the speaker of the moment of a group call by one of the listeners of said group call, said group call being established in a mobile telephony network supporting group calls.

  According to a characteristic of the invention, said method comprises the following steps: a) a step of accessing the mobile station of the requesting listener to a dedicated signaling channel in order to transmit to said network an interrupt request, b ) a network processing step of said request to decide whether to interrupt said speaker, and c) a speaker interruption step when said network has decided said interrupt.

  According to another characteristic of the present invention, for transmitting said interrupt request, said mobile station of the requesting listener accesses a part 2880761 3 of said dedicated signaling channel reserved for any transmission of interrupt request of a mobile station auditor.

  Advantageously, said network warns said mobile listener stations which part of said dedicated signaling channel they must use to transmit their interrupt request.

  Advantageously, said request contains an identifier of the group call to which said requesting listener belongs. It may also contain an identifier of the requesting subscriber.

  Advantageously, said method comprises a step of processing the relative priority levels of the speaker and the listener wishing to interrupt the speaker. This step of processing the relative priority levels may comprise: a substep of transmission to each of said listeners of the group call of the priority level of the speaker of the moment, a substep of comparing said priority level of the speaker transmitted to the priority level of the listener desiring to interrupt the speaker, said step being performed by the mobile station of said listener, said current speaker interrupt request being issued if the substep of comparison reveals that the priority level of said listener is at least higher than that of the speaker.

  It may also include a substep of comparing said priority level of the speaker with the priority level of the requesting listener, said step being implemented by said network, said request being rejected if the substep of comparison reveals that the priority level of said listener is at least higher than that of the speaker.

  The priority level of the requesting listener can then be transmitted at the same time as or in said interrupt request or else be known to the network.

  Advantageously, said method comprises a step of transmitting to the mobile station of said listener requesting a message as to the decision taken by the network. Said request then comprises a random number which is retranscribed in said message as to the decision taken by the network.

  The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an example embodiment, said description being made in relation to the attached drawing in which: ## EQU1 ## Fig. 1 is a diagram of a mobile telephony system implementing a group call and, in a mode of operation called 1.5-channel mode, FIG. 2 is a diagram of a mobile telephony system implementing a group call and in this mode of operation said mode 1 channel.

  In a GSM-type mobile telephone system making it possible to implement group calls, there are two modes of operation depending on the allocation to the mobile station of the speaker either of a dedicated DCH channel or of a channel of the type of traffic channel TCH, which is called, given the context, group channel GCH. The first mode of operation, generally referred to as "1.5 channel mode", is described in connection with FIG. 1. As for the second mode, generally referred to as "channel 1 mode", it is described in connection with FIG. 2.

  In these Figs. 1 and 2, there are shown two cells C 1 and C 2 of the same area of a Group Cali Area call (GCA) and at a given moment during a group call where the cell Cl covers the mobile station of a speaker L as well as the mobile stations of some of the listeners AI and A2 and where the cell C2 covers other mobile stations of listeners A3 to A5. Note that other cells can also be implemented. They are functionally equivalent to cell C2.

  In the first operating mode (Fig. 1), a talker channel DCH consisting of an upstream channel (arrow in the direction of the cell C1) and a downlink channel (arrow in the direction of the cell C1) is allocated to the mobile station of the speaker L. of the speaker station L) while at all the mobile stations of the listeners AI to A (here n = 5) is allocated a group channel GCH (single logical channel) which, at the physical level, is divided into a channel of group GCH1 for the cell C1 and in a group channel GCH2 for the cell C2, themselves each composed of a downlink (arrows towards the stations of the listeners) and a rising channel but the latter is not used (hence the absence of arrows in Fig. 1). It will be specified that the channels GCH1 and GCH2 are physical channels.

  In the second mode of operation (Fig. 2), there is no channel dedicated to the mobile station of the speaker L as before. On the other hand, a single group logical channel GCH (here again a group channel GCH1 and a group channel GCH2 for respectively the cells C1 and C2) is allocated to all the mobile stations of the subscribers of the group in communication, which they are speaker or listeners. The upstream channel of the group GCH channel is allocated to the only mobile station of the speaker L 2880761 5 while the downlink is allocated to all the mobile stations of the subscribers of the group. The speaker's mobile station may optionally disable its own reception of the downlink channel of the group GCH to avoid echo phenomena.

  As mentioned in the preamble of the present description, the upstream channels GCH1 and GCH2 can not be used by the mobile stations of the listeners A1 to A5.

  According to the present invention, a mobile station of a listener who wishes to interrupt the speaker issues a speaker interrupt request R on a dedicated signaling channel. For example, it may be the channel SDCCH in GSM, channel normally provided for the transport of the signaling for the purpose of establishing a call and updating the location, for example. It is also used to transport SMS short messages.

  In practice, only part of this SDCCH signaling channel is reserved by the network for this particular application. Information is transmitted from the network to the listener mobile stations to warn them which part of the SDCCH signaling channel they should use to issue their interrupt request R. The interrupt request R is specific to a speaker interrupt request a group call. It may contain an identifier ID of the relevant group call, although this is not strictly necessary since the SDCCH signaling channel is dedicated. The identifier ID which is involved here is for example that described in chapter 9 of 3GPP TS 03.68.

  It can also be accompanied by a random number which will be used for the recognition of the response to the request made by the network and which allows the mobile station to ensure that this response is intended for him. It is accompanied by an identifier of the requesting subscriber, such as the International Mobile Subscriber Identity (IMSI) or Temporary Mobile Subscriber Identity (TMSI), described in Chapter 2 of 3GPP TS 03.03.

  The network receives the request R emanating from the requesting mobile station (in this case the mobile station A4), processes it to decide whether to interrupt the speaker or not, and returns, on the downlink of the group channel GCH, an answer REP on this decision. In this REP response, is copied, if necessary, the random number of the request which allows the mobile station applicant to ensure that this answer is intended for him.

  In case of a decision to interrupt, the network causes the interruption so that the speaker becomes a listener and the DCH dedicated channel or the upstream channel of the group GCH, as the case may be, is now assigned to the requesting mobile station, in this case the mobile station A4, which becomes mobile speaker station. The mobile station of the requesting party A4 goes into group transmission mode, for example, upon receipt of the network response. The network also transmits an interrupt command to the speaker's mobile station which then goes into group receive mode.

  The processing performed by the network consists in determining the identity of the requesting listener on the basis of his subscriber identifier (for example IMSI or TMSI) contained in the request R, determines the group call concerned by the request of this listener, and this, on the basis of the ID group ID contained in the query, and deduced from this group call the identity of the speaker of the moment. It is on the basis of the identity of the requesting listener and the identity of the speaker that the decision is made to interrupt or not the speaker.

  An alternative embodiment is described in relation to FIG. 3. A mobile station of a listener wishing to interrupt the speaker of the moment of a group call leaves its active mode of operation (active mode) and goes into the idle mode of operation, called "idle" mode. Then, it performs, as previously, access to the common access channel such as the RACH channel. The network acknowledges the reception of this access on the channel provided for this purpose, namely the AGCH channel, which points to a dedicated SDCCH signaling channel on which the mobile station identifies and then transmits the interrupt request R. The REP response from the network to this request is performed on the downlink of the GCH group channel as before. The requesting mobile station reverts to its active mode of operation.

  The advantage of this variant is to be able to perform the request R on a dedicated signaling channel and, for this purpose, to use the known network access protocol.

  The system of the present invention may provide for the processing of a priority of being a speaker. According to a first embodiment, this priority processing is performed at the mobile stations. At the moment when a mobile station becomes the station of the speaker of a group, it informs the network of its identity but also of its priority level, for example by means of a specific message, such as the message said "TALKER INDICATION "as defined in ETSI TS 100 940 in Chapter 9.1.44. The network then informs, by a message that can be called "TALKER INFORMATION" transmitted on the downlink of the GCH group channel, each mobile station of the group of the priority level of the mobile station of the speaker of the group.

  It will be noted that the information concerning the part of the SDCCH signaling channel assigned to the speaker interruption could be placed in the "TALKER INFORMATION" message.

  At the time the listener makes a request to interrupt the speaker, his own mobile station, prior to the transmission of the request, compares the priority level of the current speaker to his. If it is less than or equal to his, the request is transmitted to the network as previously described. On the other hand, if it is superior, the request is not transmitted and the requesting auditor is informed that his request is directly rejected.

  According to another embodiment, this priority processing is performed at the network level. When the listener's request is received by the network, the network compares the priority level of the current speaker with the priority level of the requesting listener. The network is aware of this level either because it is registered in the request itself or because it is known to the network (it is for example contained in a database listing for each listener its priority level) . If the priority level of the speaker is less than or equal to the priority level of the requesting listener, the request is accepted and is rejected in the opposite case.

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Claims (12)

  1) A method of interrupting the speaker of the moment of a group call by one of the listeners of said group call, said group call being established in a mobile network supporting group calls, characterized in that it comprises the following steps: a) an access step of the mobile station of the requesting listener to a dedicated signaling channel in order to transmit to said network an interrupt request, b) a step of processing by the network of said request for decide whether to interrupt said speaker, and c) a step of interrupting the speaker when said network has decided said interruption.   2) Interrupt method according to claim 1, characterized in that, to transmit said interrupt request, said mobile station of the requesting listener accesses a part of said dedicated signaling channel reserved for any interrupt request transmission. of a mobile auditor station.   3) A method of interruption according to claim 2, characterized in that said network warns said mobile listening stations which part of said dedicated signaling channel they must use to transmit their interrupt request.   4) Interrupt method according to one of the preceding claims, characterized in that said request contains an identifier of the group call to which said requesting listener.   5) Interrupt method according to one of the preceding claims, characterized in that said request contains an identifier of the requesting subscriber.   6) A method of interruption according to one of the preceding claims, characterized in that it comprises a step of processing the relative priority levels of the speaker and the listener wanting to interrupt the speaker.   7) Interrupting method according to claim 6, characterized in that said step of processing the relative priority levels comprises: a substep of transmission to each of said listeners of the group call of the priority level of the speaker of the moment, - a substep of comparing said priority level of the speaker transmitted to the priority level of the listener wanting to interrupt the speaker, said step being implemented by the mobile station of said listener, said request for interruption of the speaker of the moment being issued if the substep of comparison reveals that the priority level of said listener is at least higher than that of the speaker.   The interrupting method according to claim 6, characterized in that said step of processing the relative priority levels comprises a substep of comparing said priority level of the speaker with the priority level of the requesting listener, said step being implemented by said network, said request being rejected if the substep of comparison reveals that the priority level of said listener is at least higher than that of the speaker.   9) Interrupt method according to claim 8, characterized in that the priority level of the requesting listener is transmitted at the same time as or in said interrupt request.   10) Interrupt method according to claim 8, characterized in that the priority level of each of the subscribers of a group call is known to the network.   11) A method of interruption according to one of the preceding claims, characterized in that it comprises a step of transmission to the mobile station of said listener requesting a message as to the decision taken by the network.   12) Interrupt method according to claim 11, characterized in that said request comprises a random number which is retranscribed in said message as to the decision taken by the network.