Optimal SIR-based power control in 3G wireless CDMA networks

One aspect of the wireless communications power control problem that has received little attention is design of control algorithms that explicitly consider tradeoffs between transmit power SIR error costs. In this paper, we propose an novel optimal control algorithm for distributed power control in cellular communication systems. We assume that each mobile acts independently. The interference caused by the transmissions of mobiles in other cells is lumped with the background interference. We define a cost for each mobile that consists of a weighted sum of power, power update, and signal-to-interference ratio (SIR) error and obtain the corresponding, optimal control law assuming the interference value does not change significantly from one measurement to the next. Simulation results demonstrate the superiority of the proposed controller to the power balancing algorithm in minimizing power usage.