Markov chain models for the investigation of fast power control for FDD-UMTS

Transmission power control (TPC) is essential in third generation systems for several reasons. Fast power control (or closed-loop power control) is intended to track fast channel fading. We investigate fast power control for FDD-UMTS with the help of Markov chain models in order to obtain analytical results of the performance. The effect of TPC errors and SIR estimation errors is explained. The Markov chain models are derived for small velocities, but can be considered as bounds for moderate speeds as well. We also explain how SIR estimation errors can be modelled as TPC errors.