Group radio with subscriber-radio controlled channel selection

摘要

A point-to-multipoint (PTM) communication system (20) includes a cellular radio infrastructure (22) having base stations (32) implemented in satellites (34) placed in low earth orbits (38). PTM subscriber radios (24) share common cellular radio infrastructure (22) multipoint channels (52) to engage in a common PTM communication session while the cellular radio infrastructure (22) also conveys point-to-point communications. A group control computer (28) constructs a channel list (126) which is downloaded to PTM subscriber radios (24). The channel list (126) identifies multipoint channels (52) and indicates when and where the channels (52) are active. Without emitting transmissions to the cellular radio infrastructure (22), PTM subscriber radios (24) autonomously switch to new multipoint channels (52) in response to their current time and location and the channel list (126).