Content for  TS 43.068  Word version:  18.0.0

When application-specific data is to be sent and the talking subscriber is allowed to transmit application-specific data for the respective group ID, the mobile station of the talking service subscriber shall send a DATA INDICATION (Application_Data) message to the network on the uplink of the dedicated channel or group call channel. On receipt of the application-specific data, the network shall transmit these data to the other group call members as specified in subclause 4.2.8.4.

When application-specific data is to be sent and the network indicates the uplink as free, the listener shall use the group call channel uplink for the signalling as specified in item a) below. Otherwise, when the network does not indicate the uplink as free, the channel to be used by the listener is indicated by the network in the "uplink access indication" IE sent in periodic transmissions of the UPLINK BUSY message. If the talking service subscriber uses the group call channel uplink in the current cell, the RACH shall be used, see item b) below; otherwise the group call channel uplink shall be used, see item a) below.

On receipt of the UPLINK APPLICATION DATA, the MSC shall check if the sending subscriber has a subscription to the group ID. If yes, the MSC shall distribute the application-specific data dependent on the distribution parameter included in the DATA INDICATION or DATA INDICATION 2 message; otherwise the MSC shall discard the UPLINK APPLICATION DATA message. Without a RANflex configuration, the MSC can perform this check locally with its own VLR. In a RANflex configuration with or without group call redundancy, if the group call serving MSC receives an UPLINK APPLICATION DATA message it shall check by analysing the NRI of the requesting subscriber's TMSI whether it is the requesting subscriber's VMSC. If it is not, the group call serving MSC shall retrieve the IMSI and information about subscribed talker priorities from the VLR of the VMSC by means of the MAP service SEND_GROUP_CALL_INFO. During this MAP operation the VMSC shall check the subscription for the group ID. If the application-specific data are to be sent to the listeners and the talking service subscriber, the MSC shall proceed as follows: If the MSC is the anchor MSC, it shall put the application data and optionally the mobile subscriber's MSISDN into the BSSMAP message NOTIFICATION DATA and distribute the message towards all relay MSCs and all BSSs in its MSC area involved in the group call (figure 7f). If the MSC receives an indication from the originating BSC that the application-specific data were immediately distributed to the originating BSS area (see subclause 4.2.8.4.2), the MSC shall not send the BSSMAP message NOTIFICATION DATA to the originating BSS. If the MSC is a relay MSC, it shall put the application data and optionally the mobile subscriber's MSISDN into the BSSMAP message NOTIFICATION DATA and distribute the message to the anchor MSC and all BSSs of the relay MSC area. If the MSC receives an indication from the originating BSC that the application-specific data were immediately distributed to the originating BSS area (see subclause 4.2.8.4.2), the MSC shall not send the BSSMAP message NOTIFICATION DATA to the originating BSS. On receiving the NOTIFICATION DATA message from the relay MSC, the anchor MSC shall send the message towards all BSSs in its MSC area involved in the group call and to all relay MSCs except the relay MSC from which the NOTIFICATION DATA was received (figure 7h). The BSS shall broadcast the notification data to all listeners and talking service subscriber in the NOTIFICATION APPLICATION DATA message on the FACCH. The network may repeat the NOTIFY APPLICATION DATA message for application-specific data on the group call channel downlink. If a mobile station receives the NOTIFY APPLICATION DATA message more than once, it shall deliver only the first received message to its local application and discard any received repetitions of the message. The mechanism how the mobile station detects a repetition of the NOTIFY APPLICATION DATA message is application- specific.

As a network option, on receipt of application-specific data from the MS, the BSS may distribute the application-specific data immediately to the cells within the BSC area belonging to the group call area, if the distribution parameter included in the DATA INDICATION message or DATA INDICATION 2 message indicates that the application-specific data are to be sent to the service subscribers. In addition, the BSC shall send the application-specific data to the MSC with an indication that the application-specific data were already distributed to the originating BSC area. When this network option is used, the BSS cannot include the mobile subscriber's MSISDN in the NOTIFY APPLICATION DATA message broadcast immediately to the cells within the BSC area. Furthermore, the BSS cannot check if the sending subscriber has a subscription for the group ID. If the network option of immediate distribution of application-specific data by the BSS is activated, then during the establishment phase of the voice group call the BSC shall store the cell identities of the cells belonging to the group call area and served by the BSC.