| 摘要 |
A method and system for peer-to-peer communication among a plurality of sites in a land mobile radio (LMR) system. The sites are interconnected by a data network, such as an IP network. Each site transmits a periodic broadcast message, which includes the identity of the transmitting site and a list of target groups that the transmitting site is interested in participating. The message is received by the other sites, thus each site becoming aware of the presence of all other sites in the system and Talk Groups they are interested in. When a site, referred to as the initiating site, intends to communicate with other sites, the initiating site transmits a call request message. The call request message is multicast over the data network to the intended recipients. The initiating site receives an acknowledgement message from the other sites confirming their willingness to communicate with the initiating site. The initiating site then sends a voice message, via multicasting, to the other sites interested in the call. Among various advantages, the system reduces hop counts for the call setup, and latency is decreased because call control is distributed among the sites. Furthermore, the system does not have a single point of failure since control and bearer plane traffic need no longer go through a bridge device.
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