Soft dropping power control-a power control backoff strategy

Abstract

For wireless communications systems, this work considers a power control algorithm in which a user's link quality objective, as measured by the signal to interference ratio (SIR), varies with its transmitter power. In particular, as increased interference or reduced uplink gain leads a mobile to raise its transmitter power, that mobile lowers its SIR target. In this way, the likelihood of an infeasible power control problem in which the users' transmitter powers rise to a maximum, is reduced. This graceful degradation of the SIR is termed soft dropping. Convergence proofs for a soft dropping power control algorithm are presented. Simulation results for a generic CDMA system demonstrate performance improvements over fixed target SIR algorithms.