RELAY MULTICAST TRANSMISSION METHOD AND RELAY MULTICAST TRANSMISSION SYSTEM

The present application provides a method and a system for relay multicast transmission, a relay selection server, relay nodes and terminals. According to the present application, the first terminal sends a relay selection request to the relay selection server; the relay selection server determines, according the relay selection request, multiple second terminals which will communicate with the first terminal, and determines the multicast relay node corresponding to at least two second terminals, and sends relay multicast notification to the first terminal and the multicast relay node separately; the first terminal sends a piece of data to the multicast relay node, and said multicast relay node copies the data from the first terminal and multicasts the data to at least two corresponding second terminals. According to the present application, terminals only need to send a piece of data to the multicast relay node, and the data are copied and multicasted to multiple other terminals by the multicast relay node, thereby improving the transmission efficiency.