An Asynchronous Distributed Algorithm for Power Control in Cellular Radio Systems

We give an asynchronous adaptive algorithm for power control in cellular radio systems, which relaxes the demands of coordination and synchrony between the various mobiles and base stations. It relaxes the need for strict clock synchronization and also allows different links to update their power at different rates; unpredictable, bounded propagation delays are taken into account. The algorithm uses only local measurements and incorporates receiver noise. The overall objective is to minimize transmitters’ powers in a Pareto sense while giving each link a Carrier-to-Interference ratio which is not below a prefixed target. The condition for the existence and uniqueness of such a power distribution is obtained. Conditions are obtained for the asynchronous adaptation to converge to the optimal solution at a geometric rate. These conditions are surprisingly not burdensome.