Patent ID: 8442027

Claim:
A mobile station configured to establish synchronization in an uplink, when a reception state is shifted from a discontinuous reception state to a continuous reception state, the mobile station comprising: a receiver unit configured to receive a control channel and a downlink data channel; a control information processor unit configured to change a discontinuous reception cycle according to radio resource notification control information included in the control channel received in the receiver unit; an analyzer unit configured to determine whether or not an uplink synchronization request designating a data series for identifying a mobile station is included in the downlink data channel received in the receiver unit; a random access channel transmission manager unit configured to determine whether or not a random access channel transmission timer has expired, when it is determined by the analyzer that the uplink synchronization request is included; the random access channel transmission manager unit determining whether or not to transmit a non-synchronization random access channel, when it is determined that the random access channel transmission timer has not expired; a transmitter unit configured to transmit the data series for identifying the mobile station by using the non-synchronization random access channel, when it is determined that the random access channel transmission manager unit can transmit the non-synchronization random access channel; the random access channel transmission manager unit determining whether or not a command for adjusting a transmission timing in the uplink is included in the downlink channel; a transmission timing controller unit configured to establish uplink synchronization by controlling the transmission timing in accordance with the command for adjusting the transmission timing; and a Hybrid Automatic Repeat Request (HARQ) transmission manager unit configured to return transmission acknowledgment information for downlink data, when the command for adjusting the transmission timing in the uplink is included, wherein the random access channel transmission manager unit transmits the data series for identifying the mobile station using the non-synchronization random access channel, when the command for adjusting the transmission timing is not received for a predetermined time period; and wherein the random access channel transmission manager unit transmits the data series for identifying the mobile station using the non-synchronization random access channel, when the downlink data is received before establishing uplink synchronization.