Global stability of feedback power control algorithms for cellular radio networks

Power control is considered as an efficient scheme to mitigate co-channel and multiple-access interference in cellular radio systems. Various approaches have been proposed in recent years to design power control algorithms. We focus on the feedback algorithms that are based on signal-to-interference-plus-noise ratios (SIR-based algorithms). We review SIR threshold approach and then discuss how power control design can be formulated as a decentralized regulation problem. We use a robust control framework to analyze global stability of a network on a single channel. We obtain a sufficient condition, which guarantees that the deviations of the power levels from their optimal values remain bounded, even when the channel gains change, as long as the network stays feasible.