Power Control Algorithm in Wireless Communication System

A distributed power control algorithm based on SIR estimation is proposed for a CDMA cellular system and a classical result of stochastic approximation is applied in this scheme. The power control algorithm is first converted into one stochastic approximation problem that seeks for the zero point problem of one certain function. In this distributed algorithm, each user iteratively updates its power level by estimation of SIR. It does not require any knowledge of the channel gains or state information of other users. Hence, the algorithm is robust. It is proved that the algorithm converges to the optimal solution in the sense of mean-squared.