This paper proposes a client architecture for the Push to Talk over Cellular (PoC) service based on the Open Mobile Alliance (OMA) PoC specifications v1.0 release. We show that most standard VoIP modules can be reused for the PoC client, and the VoIP software can be easily extended to support PoC service. Then we present the detailed message flows between the PoC client and other network entities in the PoC system.
Push to Talk over Cellular (PoC) service provides a walkie-talkie like service in the cellular communication infrastructure. In this service, several predefined PoC group members participate in one PoC session. Since the PoC session is half-duplex, only one group member speaks at a time, and the others listen.
Therefore, a user must ask for the floor (the permission to speak) by pressing the push-to-talk button before he/she starts to talk. In this paper, we implement a PoC client in the WLAN environment with some variation from the Open Mobile Alliance (OMA) PoC specifications v1.0 release.
Source: Open Mobile Alliance