Transmission power control in a CDMA/TDD radio communication system

In addition to a structure of a conventional CDMA/TDD radio communication system, a base station (100) includes a pilot signal generating circuit (15) for generating a pilot signal (26) that has a constant transmission power level and is known in mobile units (200) and a pilot channel spreading circuit (16) for transmitting the pilot signal (26) to the mobile units (200) through a transmission line (5). Each of the mobile units (200) includes a pilot signal reception level measuring circuit (19) for measuring reception power of the received pilot signal and a transmission power control circuit (8) for controlling transmission power of a power amplification circuit (10) based on the measured reception power of the received pilot signal.