Mobile communication system for low power consumption, call control server and access gateway

A mobile communication system, comprising:

• a plurality of base stations to which mobile terminals are to be connected;
• and
• a plurality of call control servers that accommodate the mobile terminals based on a location registration request, wherein:
• the plurality of call control servers include at least a first call control server and a second call control server, and
• an identifier identifying one of the call control servers which accommodates the mobile terminals and that is assigned to each of the mobile terminals,
• the first call control server is configured to:
• calculate a load on the first call control server based on a processing amount of control signals between the plurality of base stations and the first call control server;
• and
• cause at least one of the mobile terminals accommodated in the first call control server to transmit the location registration request in a case in which it is judged that the load on the first call control server is low, based on at least one of a result of comparison between the calculated load and a predetermined threshold value and a result of comparison between the number of mobile terminals accommodated in the first call control server and a predetermined number;
• the one of the plurality of base stations corresponding to the one of the mobile terminals is configured to:
• select the second call control server into which the one of the mobile terminals is to be newly accommodated from among the plurality of call control servers in a case in which the location registration request transmitted from the one of the mobile terminals is received;
• and
• forward the location registration request to the selected second call control server;
• the second call control server is configured to accommodate the one of the mobile terminals in a case in which the forwarded location registration request is received;
• and
• the first call control server is further configured to switch to a power-saving state after all of the mobile terminals which are assigned the identifier representing the first call control server are accommodated into the second call control server.