Subscriber unit transmission prevention method e.g. for vicinity of radioastronomy observatory

摘要

The method involves repetitive transmission of a radio beacon control signal (46) to subscriber units (49,51,55) inside a protection zone (58). The control signal includes a transmission prevention parameter which invalidates the transmission capacity of each unit on reception of the parameter in the control signal. The radio beacon control signal is synchronised with the control signal for a satellite (14) serving the subscriber units. The radio beacon control signal is compatible with the receiver in the subscriber unit. In the protected zone, the beacon signal is stronger than the satellite control signal and the subscriber unit does not respond to the satellite. The subscriber unit can be a cellular radio telephone.