Mobile communication system and base station

Abstract

There is a problem that when a closed subscriber group (CSG) cell available to subscribers is installed in a macro cell area, communication cannot be performed due to the interference between a macro cell and the CSG cell in an area thereof. The CSG cell that is provided in the CSG cell area and transmits a downlink synchronization signal using a radio frame assigns control signals to a first subframe and a second subframe among a plurality of subframes constituting the radio frame, and the macro cell that is provided in the macro cell area and transmits a downlink synchronization signal using the radio frame assigns control signals to a third subframe and a fourth subframe, which are shifted from the first subframe and the second subframe by a predetermined number of subframes, respectively, among the plurality of subframes constituting the radio wave, the CSG cell and the macro cell being configured to perform transmission in synchronization with each other.

1 . A mobile communication system comprising:
 at least one user equipment; and   a plurality of base stations that perform radio communication with the at least one user equipment,   wherein, in a case where a first base station of the plurality of base stations is an interference control base station to control interference occurring between the first base station and a second base station of the plurality of base stations, timing of radio communication of the first base station is synchronized with that of the second base station.   
     
     
         2 . A base station that performs radio communication with at least one user equipment,
 wherein the base station synchronizes, in a case where another base station is an interference control base station to control interference occurring between the base station and the other base station, timing of radio communication of the base station with that of the other base station.