We Claim:
1. A mobile communication system in which a plurality of base stations are
configured to perform radio communication with a user equipment in a coordinated
manner with each other, wherein
measurement target information is transmitted from a base station among the plurality of base stations to the user equipment, the measurement target information indicating a signal to be measured by the user equipment among signals transmitted from the plurality of base stations, and
measurement result information is transmitted from the user equipment to the base station, measurement result information indicating a measurement result of a measurement target signal indicated by the measurement target information.
2. The mobile communication system as claimed in claim 1, wherein the measurement target signal is a reference signal to be measured by the user equipment for obtaining a state of the channel.
3. The mobile communication system as claimed in claim 1, wherein the measurement target information is transmitted using a dedicated communication signal dedicatedly provided for the user equipment.
4. The mobile communication system as claimed in claim 1, wherein the measurement target information is transmitted using a radio resource control (RRC) signaling.

5. The mobile communication system as claimed in claim 1, wherein a signal
notifying that the measurement target signal is released from a measurement target is
transmitted from the base station to the user equipment.
6. The mobile communication system as claimed in claim 1, wherein measurement result information is transmitted from the user equipment to the base station periodically.
7. A base station configured to perform radio communication with a user equipment in a coordinated manner with another base station, wherein
the base station is configured to transmit measurement target information to the user equipment, the measurement target information indicating a signal to be measured by the user equipment among signals transmitted from the base station and the other base station, and
the base station is configured to receive measurement result information from the user equipment, measurement result information indicating a measurement result of a measurement target signal indicated by the measurement target information.
8. A user equipment configured to perform radio communication with a
plurality of base stations which are configured to operate in a coordinated manner with
each other, wherein
the user equipment is configured to receive measurement target information from a base station among the plurality of base stations, the measurement target

information indicating a signal to be measured by the user equipment among signals transmitted from the plurality of base stations, and
the user equipment is configured to transmit measurement result information to the base station, measurement result information indicating a measurement result of a measurement target signal indicated by the measurement target information.