| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission power control method for the first uplink data transmission in the random access channel (RACH) procedure.SOLUTION: Medium access control (MAC) 110 of a user apparatus (UE) 102 transmits a random access preamble 116 at a nominal transmission power level, when starting access to a base station 104. The base station 104 transmits a random access preamble response (RAR) when the random access preamble 116 can be received. The MAC 110 gradually increases the transmission power level at a predetermined step, if the RAR from the base station 104 cannot be obtained, and repeats the operation until the maximum number of preambles is reached. When the base station 104 can receive the random access preamble, the data 144 of transmission power control (TPC), where a sufficient power spectrum density has been taken into account on the basis of the received power level, is also contained in the RAR, and transmission power of the UE 102 is controlled appropriately. |
