Patent ID: 8200169

Claim:
A mobile communication system comprising: a first priority communication system which performs a first priority communication by using a first frequency band, a second priority communication system which performs a second priority communication by using a second frequency band and has a lower priority level than the first priority communication, and a non-priority communication system which uses a third frequency band, wherein the first frequency band, the second frequency band, and the third frequency band are adjacent to each other, a first communication enable signal transmitter apparatus in the first priority communication system is configured to transmit a first communication enable signal to allow the second priority communication system to perform a communication by using a frequency channel of the second frequency band, in accordance with location information of a first base station in the first priority communication system and a communication status of a first mobile station in the first priority communication system, a second base station in the second priority communication system is configured to be enabled to transmit, to a second mobile station, a signal by using a frequency channel of the second frequency band, when the second base station receives the first communication enable signal from the first priority communication system or when the second base station detects that the second mobile station in the second priority communication system has received the first communication enable signal, a second communication enable signal transmitter apparatus in the second priority communication system is configured to transmit a second communication enable signal to allow the non-priority communication system to perform a communication by using a frequency channel of the third frequency band, in accordance with the first communication enable signal, location information of the second base station and a communication status of the second mobile station, and a third base station in the non-priority communication system is configured to be enabled to transmit, to a third mobile station, a signal by using a frequency channel of the third frequency band, when the third base station receives the second communication enable signal from the second priority communication system or when the third base station detects that the third mobile station in the non-priority communication system has received the second communication enable signal.