A new call control scheme of push-to-talk system

摘要

For Push-to-Talk (PTT) system based on public mobile data network (such as Gprs/cdma2000 1x), a small call delay is the key fact which influent the system's practicability. In this paper, we provide a new call control scheme for PTT system. By making use of the apriority knowledge of PTT call model and priority control, in this scheme, the signaling message and voice data are encapsulated in a same data packet, so that voice data can reach the called user without waiting for the signaling exchanging. Thus the call delay can be decreased significantly. The experiment result based on the commercial cdma 20001X network of China Unicom shows that the call delay can be decrease to 600ms, which approach to the traditional trunk communication system's requirement.