Voice Group Call » History » Revision 2
Revision 1 (laforge, 11/05/2020 10:05 AM) → Revision 2/4 (laforge, 11/20/2022 06:25 PM)
h1. Voice Group Call (VGCS) Voice Group Calls are part of the [[ASCI]] features introduced primarily for GSM-R. They're basically the _bigger brother_ of [[Voice_Broadcast_Call]] (VBS). So if you're unfamiliar with the former, it is suggested to first read up on VBS. While VBS calls are unidirectional, VGCS calls are bi-directional between multiple parties. There's always one _talker_ and many _listeners_. The talker can change dynamically over time, basically creating a user experience of a classic two-way radio. There is always only one talker active at any moment. Like VBS, VGCS works with the concept of _groups_. Eachs subscriber can be part of up to 50 groups, and calls are made to a specific group. There can be any number of parallel groups active in parallel next to each other. Each group has an _area_ describing a list of cells in which subscribers can participate in the group call. h2. Arbitration A subscriber who wishes to talk signals this to the network. The right to talk is allocated on a first-come-first-serve basis without queuing. h2. Specifications GSM-R For more information, see * 3GPP TS 42.068 (Stage 1) * 3GPP TS 43.068 (Stage 2) * 3GPP TS 44.068 (Stage 3; GCC Layer 3 Protocol)
