PTT + IMS = PTM - towards community/presence-based IMS multimedia services

The specification of the IP multimedia subsystem as a service delivery architecture for next generation networks and the introduction of push to talk (PTT) as an IMS based service moves VoIP applications for mobile devices already to the market. PTT has gained a strong following in the US market and is on the verge of spreading globally. The open mobile alliance (OMA) currently specifies PTT as an IMS based service to assure interoperability between different operator domains. Most PTT solution vendors think already about extending PTT with other media types then voice, like video communication, file transfer or service subscription for content push services. Thus, push to multimedia (PTM) does not seem to be that far away from market and is well suited as an enabler to provide IMS applications with advanced multimedia communication functionalities. The department for Next Generation Network Integration (NGNI) at Fraunhofer Institute FOKUS has created a PTM application that utilises the IMS architecture. This paper reports about a concept of integrating this PTT/PTM functionality in community based applications to enable already existing groups and communities with new communication features.