A Novel Distributed Power Control Algorithm for Classes of Service in Cellular CDMA Networks

Abstract

The paper proposes a distributed power control algorithm for integrating heterogeneous transmitting sources, which have a broad range of statistical/burstiness characteristics and quality of service requirements, in wideband cellular CDMA networks. Speech sources with silence detection and data are canonical examples of service classes. Each service class is characterized by on-off transmissions with characteristic probabilities, desired minimum carrier-to-interference ratio and minimum probability with which the latter is required to be satisfied. In the power control algorithm given here, the received power for each service class at each cell is adapted locally based on only local measurements of the mean and also, importantly, the variance of the interference. The algorithm is derived from an asymptotic analysis in which the bandwidth as well as the number of mobiles are large. The analysis leads to a Gaussian approximation to the interference at each cell, which depends on the power levels. The algorithm is remarkable for its simplicity in the decoupling between classes. This is due in part to an attractive product-form in the expression for the dominant term in the asymptotic expansion of the desired power for each service class and cell. A condition for geometric convergence of the adapted power to the ideal power is obtained. The condition is remarkably unburdensome and only slightly more demanding than the condition based on the mean values of source activities. The condition also defines the capacity of the cellular CDMA network.