TRANSMISSION POWER CONTROL FOR MOBILE RADIO COMMUNICATIONS USING A CDMA AND VITERBI CODING

摘要

A transmission power control method for controlling transmission power of radio communications in a CDMA system. The transmission power of a first transmitted signal transmitted from a first station is determined by a transmission power control signal contained in a second transmitted signal sent from a second station. The first station receives the second transmitted signal in the form of convolutional codes, and decodes it by using a first Viterbi decoder (15) and a second Viterbi decoder (16). The first Viterbi decoder (15) includes a path memory with the path history length of a first predetermined length, and the second Viterbi decoder (16) includes a path memory with the path history length of a second predetermined length which is shorter than the first predetermined length. The transmission power control signal contained in the second transmitted signal is extracted from the output of the second Viterbi decoder, whereas the other information data is obtained from the output of the first Viterbi decoder. The first station controls the transmission power of the first transmitted signal on the basis of the extracted transmission power control signal. This makes it possible to achieve highly accurate, fast responsive transmission power control.