Patent ID: 7860505

Claim:
A mobile communication system including a radio access network having at least two base stations and being managed by a mobile switching center, the mobile communication system comprising: an extension transmission/reception server, provided in the radio access network, configured to transmit/receive data with a first base station of the at least two base stations using an extension transmission/reception of data in the radio access network; a connection information database configured to store connection information which includes a first information and a second information, the first information associating a first base station, connected to a first mobile station, with an identifier of an extension transmission/reception server connected to the first base station and an IP address of the extension transmission/reception server, the second information associating a second base station, connected to a second mobile station, with an identifier of an extension transmission/reception server connected to the second base station and an IP address of the extension transmission/reception server; a first determination unit configured to determine to transmit/receive user data using extension transmission/reception when traffic load of each of the first base station and the second base station is lower than an acceptable threshold, and configured to determine not to transmit/receive user data using extension transmission/reception when the traffic load exceeds the acceptable threshold, a second determination unit configured to determine whether common extension transmission/reception servers exist between the first and second base stations with reference to the connection information when the first determination unit determines to transmit/receive user data using extension transmission reception, the common extension transmission/reception server being configured to transmit/receive user data between the first mobile station and the second mobile station using extension transmission/reception; and a selection unit configured to select one of the common extension transmission/reception server from the available extension transmission/reception servers, when available extension transmission/reception servers common between the first and second base stations exist, and to derive an IP address corresponding to an identifier of the selected one of the common extension transmission/reception servers, wherein the selection unit is configured to select the common extension transmission/reception server based on traffic load or process capacity of the available extension transmission/reception servers.