Mobile communication method, radio base station, and relay node

A mobile communication method comprising:

• a step of transmitting, by a relay node, a signal to a mobile station in a subframe other than an MBSFN subframe;
• a step of setting, by a radio base station, the MBSFN subframe to be included in a returnable period of a random access response;
• and
• a step of transmitting, by the radio base station, a random access response to the relay node in the MBSFN subframe of the returnable period of the random access response when a random access preamble is received from the relay node.

A mobile communication method comprising:

• a step of transmitting, by a relay node, a signal to a mobile station in a subframe other than an MBSFN subframe;
• a step of releasing, by the relay node, setting of the MBSFN subframe while stopping transmitting a signal to the mobile station when a random access procedure is started;
• and
• a step of transmitting, by the radio base station, a random access response to the relay node within a returnable period of a random access response when a random access preamble is received from the relay node.

A radio base station, comprising:

• a broadcast information transmission unit configured to transmit broadcast information including a returnable period of a random access response for a mobile station and a returnable period of a random access response for a relay node;
• and
• a random access procedure execution unit configured to transmit a random access response to the mobile station within the returnable period of the random access response for the mobile station when a random access preamble is received from the mobile station, and to transmit a random access response to the relay node in an MBSFN subframe of the returnable period of the random access response for the relay node when a random access preamble is received from the relay node, wherein
• in the MBSFN subframe, transmission of a signal addressed to the mobile station is not performed by the relay node.

A radio base station, comprising:

• a setting unit configured to set an MBSFN subframe to be included in a returnable period of a random access response;
• and
• a RA procedure execution unit configured to transmit a random access response to a relay node in the MBSFN subframe of a returnable period of a random access response when a random access preamble is received from the relay node, wherein
• in the MBSFN subframe, transmission of a signal addressed to the mobile station is not performed by the relay node.