Stochastic power control for nonlinear multiuser receivers in cellular radio networks

A cellular radio network is considered where the base station in each cell employs a linear or decision feedback multiuser receiver. A decentralized power control algorithm based on the stochastic approximation method is proposed that seeks to minimize the total transmit power while ensuring that all the users of the network achieve their quality-of-service (QoS) objective. The main technical result of this paper is that for the general class of linear and decision feedback receivers, the proposed algorithm converges in the mean-square sense to the optimal powers when the target SIRs are feasible. The feasibility region is in general much larger for well-designed multiuser receivers, particularly for nonlinear receivers that employ decision feedback detection, than it is for the linear single-user receiver. A numerical example of a bandwidth efficient 6-cell 60-user CDMA network with a total spreading gain of 20 is included