Patent ID: 6252859
Filing Date: 2001-06-26
Classification: H04W

Abstract:
A radio communications system comprisinga plurality of discrete communications channels,a plurality of talkgroups, each said talkgroup comprising a plurality of individual radio units, said plurality of individual radio units of at least one of said plurality of talk groups capable of being in communication with each other or not being in communication with each other, andcontrol means arranged to select a communication channel that is idle from said communication channels and to transmit a free channel signal on the selected communication channel,said individual radio units that are not in communication with each other being tuned to said selected communication channel in response to said free channel signal transmitted by said control means such that when a said individual radio unit that is tuned to said selected communication channel initiates communication with other radio units in its talkgroup, said individual radio unit initiating communication starts transmitting on said selected communication channel,said control means being arranged to assign said selected communication channel to said talkgroup of said individual radio unit initiating communication in response to said individual radio unit initiating communication transmitting on said selected communication channel whereby all of the individual radio units of said talkgroup of said individual radio unit initiating communication are enabled to communicate with each other on said selected communication channel.