A group call area can exceed one MSC area. In a RANflex configuration (with or without group call redundancy) a group call area can be restricted to a single pool area or can exceed one pool area. A voice broadcast call shall be initiated by a calling service subscriber by a related input function, e.g. via MMI, specifying the selected service and the group ID dialled or by a calling dispatcher by the MSISDN address (see subclause 9.2). As an option, the request of the calling service subscriber to set up a voice broadcast call may specify information to be sent as originator-to-dispatcher information to the network; in this case the originator-to-dispatcher information is included in the signalling for call setup from the mobile station to the network. It is the responsibility of the input function to ensure that the originator-to-dispatcher information has a correct format (in particular, an allowed length). The MSC in which the voice broadcast call is initiated obtains the group call attributes by requesting the Group Call Register (GCR, see clause 5). Without a RANflex configuration or in a RANflex configuration (with or without group call redundancy), if visited MSC and group call serving MSC are identical, the MSC performs a local GCR interrogation. The local GCR interrogation after call initiation also determines whether the MSC shall act as anchor- or as relay MSC. If the MSC is not the anchor-MSC then the call will be "forwarded" from the relay to the respective anchor-MSC (information also delivered by GCR) and further "call-establishment" is done by the anchor-MSC as described in the following. In a RANflex configuration the VMSC in which a voice broadcast call is initiated may be different from the group call serving MSC of the voice broadcast call initiating subscriber's location area. In this case the VMSC derives the identity of the group call serving MSC from the initiating subscriber's LAC and requests the group call anchor MSC address from the group call serving MSC by means of the SEND_GROUP_CALL_INFO MAP service. The call is then "forwarded" from the VMSC to the anchor MSC and further "call-establishment" is done by the anchor MSC as described in the following. In a RANflex configuration with group call redundancy the VMSC in which a voice broadcast call is initiated may not belong to the group call serving MSC redundancy pool of the voice broadcast call initiating subscriber's location area. In this case the VMSC derives the identity of the group call serving MSC redundancy pool from the initiating subscriber's LAC and requests the group call anchor MSC redundancy pool address from the group call serving MSC by means of the SEND_GROUP_CALL_INFO MAP service. The call is then "forwarded" from the VMSC to the anchor MSC redundancy pool and further "call-establishment" is done by the selected anchor MSC as described in the following. When a calling service subscriber or calling dispatcher initiates a voice broadcast call, one voice broadcast channel shall be established in each cell of the group call area and notifications for that call shall be sent in each of these cells. As an alternative, voice broadcast channels may only be established in cells in reaction to responses received from mobile stations on the notifications using notification response procedure. At the same time standard connections to dispatchers in the mobile network or in an external network shall be established. If originator-to-dispatcher information has been received in the signalling for call setup from the mobile station to the network and if the originating MSC supports processing of originator-to-dispatcher information, this information is transformed into user-to-user information and sent to the dispatchers as UUS1 when setting up the standard connections. The calling service subscriber shall have a dedicated standard uplink/downlink. All mobile stations of the listening service subscribers in one cell shall only listen to the same common downlink (voice broadcast channel). Only one voice broadcast channel shall be established in each cell for any given voice broadcast call, although there may be a number of simultaneous voice broadcast calls within the same cell. Service subscribers shall be notified on the voice broadcast call in each cell. These voice broadcast call notification messages shall be broadcast on the Notification CHannel (NCH). The notification messages use the group ID rather than individual TMSIs/IMSIs. If the length of the group ID is less than 8 decimal digits, then the group call area ID is used in order to enable a resolution in the case of overlapping group call areas. A service subscriber's mobile station needs to be able to recognize notification messages for those group IDs subscribed to and presently activated. The network may also send messages on appropriate voice broadcast channel FACCHs, in order to notify voice broadcast call members who may participate in other voice broadcast calls. In addition , also paging information messages for standard calls may be sent in order to inform voice broadcast call members on actually paged point to point calls. Further the network may provide notification on the voice broadcast call to service subscribers who have subscribed to the paged group ID and which are in dedicated mode. The process of broadcasting messages on NCHs is to be carried out throughout the call in order to provide the "late entry" facility whereby group members entering the area can join the call. On receiving notification of a voice broadcast call a voice broadcast call member's mobile station shall adjust to the nominated channel to receive the broadcast call if this channel was received in the notification message and receive the information on the downlink. Whilst receiving, the mobile station shall not transmit on the uplink SACCH. This group receive mode is different to the normal idle mode or dedicated mode. If no channel description was provided in the notification message, the mobile station shall establish a dedicated connection by use of notification response procedure in order to respond to the notification. The network may then provide the mobile station with a channel description for the voice broadcast call. As a further mobile station option, the mobile station may read its paging subchannel in the current cell while in group receive mode or in group transmit mode in order to receive paging messages for mobile terminated calls.

Completion of links into congested cells where pre-emption did not occur is required. If the cell in which the calling service subscriber is located is reset, the voice broadcast call shall be released. On receiving details of a voice broadcast call the user may choose to move to the notified call or the mobile station may automatically move to the notified call if the new call is of higher priority than the existing call and automatic acceptance applies for this priority level.

Within each voice broadcast call only the voice of the calling service subscriber or calling dispatcher shall be transmitted on the voice broadcast downlink channel. Mobile stations in group receive mode use the group receive mode procedure (see TS 43.022) to "camp-on" in a new cell to be able to listen to the voice broadcast channel. The mobile station may find the voice broadcast channel details of a new cell on the related NCH. A network may decide not to establish voice broadcast channels in all cells. Instead, notifications containing no channel description may be provided. If a mobile station moves to such a cell, it must establish a dedicated connection and respond to the notification by use of the notification response procedure in order to receive the voice broadcast call. The network may then establish a voice broadcast channel and inform the mobile station on the channel position. If the uplink reply procedure is applicable for the voice broadcast call, the network may obtain knowledge on whether mobile stations are listening in a cell by sending an uplink access request in an uplink free message on the broadcast call channel downlink. Mobile stations receiving such a request shall use uplink reply procedure and send uplink access bursts on the broadcast call channel uplink with the establishment cause "reply on uplink access request". If no uplink access bursts are received by the network, the network may decide to release the broadcast call channel in that cell and then provide notifications containing no channel description. The network may decide to reconfigure an existing voice broadcast call's physical channel configuration, frequencies and/or hopping sequences as well as the cell channel description. For the cell in which the broadcast call is being reconfigured, the network informs any listeners in group receive mode of the change in VBS channel description by using the VBS reconfiguration procedure (see TS 44.018). Mobile stations on receipt of the VBS/VGCS reconfiguration messages shall remain on the existing broadcast channel until indicated starting time and then apply the new configuration to the VBS call that the mobile station is currently involved in.

If a mobile station in group receive mode indicates a failure due to radio link time-out, the mobile station shall behave as specified in TS 45.008 and go back to idle mode, possibly in another cell, as determined by the cell re-selection algorithm. If a notification is received for the same cell, the mobile station shall try to reconnect.