Mobile communication system, extension transmission/reception device, base station, radio network controller and mobile station

[0051] Various embodiments of the present invention will be described with reference to the accompanying drawings. It is to be noted that the same or similar reference numerals are applied to the same or similar parts and elements throughout the drawings, and the description of the same or similar parts and elements will be omitted or simplified.

(Mobile Communication System)

[0052] A mobile communication system 100 according to an embodiment of the invention is adapted, as shown in FIG. 4, for an extended transmission / reception of user data between radio access networks 50a and 50b, in which the transmission / reception of user data between an MS 10a within a coverage of one radio access network 50a and an MS 10b within a coverage of the other radio access network 50b are effected by use of a single extension transmission / reception server 30b, without detour communications via an MSC 60 located outside a radio access network 50.

[0053] The mobile communication system 100 includes