Advanced joining into multicast group to facilitate later communication among group members

A method of establishing push-to-x over cellular (PoC) multicast communication among a set of terminals via a network system, the method comprising:

• receiving into the network system, respectively from each terminal, a JOIN message automatically generated by the terminal for seeking to join a PoC multicast group, and responsively transmitting to the terminal tuning-data that enables the terminal to tune to a multicast channel for the PoC multicast group;
• thereafter receiving into the network system, from a given one of the terminals, a PoC session initiation request;
• responsive to PoC session initiation, sending from the network system to each terminal a multicast channel listing that newly lists the multicast channel, as a trigger for the terminal to tune to the multicast channel;
• and
• thereafter multicasting PoC session content to the terminals via the multicast channel, for receipt by the terminals.

A method of establishing multicast communication from a network system to a set of terminals so as to support communication among the terminals, wherein a multicast group, with an associated multicast channel is defined for the set of terminals, the method comprising:

• each terminal automatically joining the multicast group, and each terminal maintaining tuning-data that enables the terminal to tune to the multicast channel so as to receive content that is multicast to the multicast group, the automatic joining comprising sending a multicast JOIN message;
• thereafter receiving into the network system a request to initiate a group communication among the set of terminals, the group communication comprising a push-to-x over cellular (PoC) communication;
• responsive to the request, transmitting from the network system to the set of terminals a multicast-listen signal that causes the terminals to tune to the multicast channel associated with the multicast group that the terminals had earlier joined;
• and
• responsive to the multicast-listen signal, each terminal using the tuning-data to tune to the multicast channel, and each terminal thereafter receiving on the multicast channel content that is multicast from the network system for the group communication.

A cellular wireless communication device comprising:

• a wireless communication interface;
• a user interface;
• and
• program logic executable to cause the device to carry out functions to facilitate push-to-x over cellular (PoC) multicast communication for a PoC session among parties including the cellular wireless communication device, the functions comprising:
• (i) automatically joining a PoC multicast group having an associated multicast channel, the automatic joining occurring before a PoC session initiation request is sent for the PoC session, and the automatic joining comprising sending a multicast JOIN message,
• (ii) after the PoC session initiation request is sent for the PoC session, receiving a multicast channel listing that newly lists the multicast channel as a channel available for use, and
• (iii) in response to receipt of the multicast channel listing that newly lists the multicast channel, tuning to the multicast channel so as to receive PoC communications of the session that are multicast on the multicast channel.