Patent ID: 7457371

Claim:
A transmission signal generating circuit used in a radio base station communication apparatus which transmits data to an arbitrary terminal by a CDMA scheme using a plurality of transmission channels, comprising: spreading processing circuits which are provided for the respective transmission channels, spread transmission data on the transmission channels, and output the signals as spread transmission signals; power class selecting circuits which are provided for the respective transmission channels and categorize the spread transmission signals from said spreading processing circuits into a plurality of power classes each serving as a unit of control in transmission power control; first adding circuits which are provided for the respective power classes and add/combine the spread transmission signals categorized by said power class selecting circuits for the respective power classes; multipliers which are provided for the respective power classes and adjust transmission powers of the spread transmission signals from said first adding circuits for the respective power classes by multiplying the spread transmission signals by predetermined multiplication coefficients; a second adding circuit which adds/combines the spread transmission signals from said multipliers to output a spread transmission signal obtained by combining the spread transmission signals on the respective transmission channels; total transmission power measuring means for measuring a total transmission power of each transmission channel on the basis of the spread transmission signal from said second adding circuit; nonlinear quantization means for nonlinearly quantizing the total transmission power obtained by said total transmission power measuring means and outputting a power level corresponding to the total transmission power; a power limitation control memory which outputs a multiplication coefficient indicating a power attenuation amount for a power class for which transmission power control is permitted, on the basis of the power level from said nonlinear quantization means; and selectors which are provided for the respective power classes, select, when transmission power control is permitted for the power class, a multiplication coefficient from said power limitation control memory and output the multiplication coefficient to said multiplier corresponding to the power class, and select, when transmission power control is inhibited for the power class, a multiplication coefficient formed from a predetermined fixed value, and output the multiplication coefficient to said multiplier corresponding the power class.