In the wideband code division multiple access (WCDMA) system

fast transmit power control (TPC) should overcome the pathloss caused by fast multipath fading.However

the conventional fixed step size transmit power control (FS-TPC) does not compensate the fading well due to the complexity of fast fading in Rayleigh channel.We propose and evaluate a single-bit adaptive step-size transmit power control (AS-TPC) scheme which can be applied in WCDMA.The new scheme divides the power control process into Markov states according to the received TPC command in "history".On the basis of analysis of the step-size of the channel fading

it chooses step-size according to the largest probability density of step-size of the multipath Rayleigh fading channel with respect to the period of the transmit power control.Each TPC step size is corresponding to a channel Markov states.Considering the power circuit's minimum resolving is about 0.5dB

we can decide the step size set.In this paper

the relationship between the Markov state and the TPC step-size is made out by computer simulation.The transmitter decides increasing or decreasing the transmit power according to the received TPC command.However

the changing quantity is chosen according to the current TPC command and the historical TPC commands.