Mobile station, base station, and communication method

A base station comprising:

• a receiving unit configured to receive a notification signal from a mobile station satisfying a certain condition used to determine whether or not to perform a handover, among one or more mobile stations located in a communication area of the base station;
• a notice notifying unit configured to transmit, to one or more other base stations, a notice signal for notifying the other base stations of a handover by the mobile station when the notification signal is received;
• and
• a context transmitting unit configured to transmit mobile-station context information related to the mobile station, in response to a request from any one of the other base stations.

A communication method comprising:

• determining whether or not a mobile station satisfies a certain condition used to determine whether or not to perform a handover;
• transmitting a notification signal from the mobile station to a base station forming a serving cell, when the certain condition is satisfied;
• detecting presence or absence of first communication data between the mobile station and the base station after transmission of the notification signal;
• and
• starting a handover process of the mobile station when the first communication data is detected.

A radio communication system including a mobile station and a base station communicating with the mobile station,

• the mobile station comprising:
• a notifying unit configured to transmit a notification signal to the base station when a certain condition used to determine whether or not to perform a handover is satisfied;
• and
• a handover processing unit configured to start a handover process according to presence or absence of first communication data after transmission of the notification signal, and
• the base station comprising:
• a receiving unit configured to receive the notification signal.