Radio base station, mobile station, and communication method

A mobile station comprising:

• a receiver configured to receive designation of a random access preamble from a radio base station when the radio base station has downlink user data to be transmitted to the mobile station;
• and
• a transmitter configured to transmit the designated random access preamble to the radio base station,
• wherein the receiver receives, from the radio base station, timing adjustment information prepared by the radio base station in accordance with a result of reception of the random access preamble, and allocation information about an uplink radio resource allocated to the mobile station,
• the transmitter transmits, when the mobile station does not have control data to be transmitted, a synchronization completion report to the radio base station by using the uplink radio resource specified by the allocation information, and
• the transmitter omits, when the mobile station has the control data, to transmit the synchronization completion report and transmits the control data to the radio base station by using the uplink radio resource specified by the allocation information.

A communication method comprising:

• designating, with respect to a mobile station, a random access signal when transmitting downlink data to the mobile station;
• transmitting the designated random access signal to the radio base station from the mobile station;
• transmitting, to the mobile station, timing adjustment information prepared based on a result of reception of the random access signal, and allocation information about an uplink radio resource allocated to the mobile station;
• transmitting, when the mobile station does not have control data to be transmitted, a synchronization completion report to the radio base station by using the uplink radio resource specified by the allocation information;
• and
• omitting, when the mobile station has the control data, to transmit the synchronization completion report and transmitting the control data to the radio base station by using the uplink radio resource specified by the allocation information.

A communication method comprising:

• transmitting, to a radio base station, a non-individual random access signal not designated by the radio base station when transmitting uplink data to the radio base station;
• designating, with respect to the mobile station, an individual random access signal when transmitting downlink data to the mobile station;
• when transmission of the non-individual random access signal ends in failure, transmitting the individual random access signal, in place of the non-individual random access signal, to the radio base station;
• transmitting, to the mobile station, timing adjustment information prepared based on a result of reception of the individual random access signal, and allocation information about an uplink radio resource allocated to the mobile station;
• transmitting, when the mobile station does not have control data to be transmitted, a synchronization completion report to the radio base station by using the uplink radio resource specified by the allocation information;
• and
• omitting, when the mobile station has the control data, to transmit the synchronization completion report and transmitting the control data to the radio base station by using the uplink radio resource specified by the allocation information.