Patent ID: 8483114
Filing Date: 2013-07-09
Classification: H04W

Abstract:
1. A method for communication among a plurality of sites in a land mobile radio (LMR) system, the plurality of sites being interconnected by a data network, the method comprising: causing a site initiating a call request to operate as a control point for setting up a call within a talk group and thereby negotiate among participants of the talk group an assignment of multicasting source role for the call within the talk group to the site initiating the call request, including: (a) transmitting a call request message by an initiating site that intends to communicate with one or more sites in the system, the call request message being multicast over the data network to the participants of the talk group; and (b) receiving, by the initiating site, an acknowledgement message from the other sites that are participants in the talk group confirming their willingness to communicate with the initiating site, the acknowledgement message being unicast over the data network; and conducting the call within the talk group, wherein the site initiating the call request and receiving the acknowledgement message assumes the multicasting source role for the call, including: (a) transmitting, by the initiating site, a voice message, the voice message being multicast over the data network to the participants of the talk group; and (b) receiving the multicast voice message at the other sites.