Handover into cells outside of Group Call Area in Voice Group Service
Original Publication Date: 2005-Jan-25
Included in the Prior Art Database: 2005-Jan-25
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The GSM/3G (Global System for Mobile Communications / Third Generation of mobile wireless network technology) feature Voice Group Call Service (VGCS) allows an entitled subscriber to establish Voice Group Calls within predefined Group Call Areas (GCA). When a VGCS call is established, a common channel is assigned to each cell of the whole predefined Group Call Area. As it is shown in Fig. 1, no radio channel is assigned to the cells outside the Group Call Area. In the one-channel solution of the VGCS, the talker shares the common channel together with the listeners located in the same cell. During the active period of the call, the subscribers may roam inside the predefined Group Call Area. Once a subscriber (talker or listener) is roaming outside the GCA, the radio link will be dropped. The problem is that the talker shares the common channel with the listeners in the one-channel solution. Executing a talker's handover into a cell outside of the GCA is not possible, because there is no common channel established in a cell outside of the GCA. For this reason, the standard handover procedures are not applicable in this case.