Time Variant Power Control in Cellular Networks

We study the transmission power control in a cellular network where the mobility of users results in a time varying gain matrix. A framework for evaluating the channel quality in a time variant system is de ned, and an asymptotic representation of the link gain evolution in time is developed. Then a variant of a standard distributed constrained power control which copes with user mobility is derived. The standard and the time variant power controls, as well as constant received power and constant transmitter power algorithms are compared with respect to their outage probabilities. The testbed is a Manhattan-like microcellular system. Our numerical examples reveal that the classical Distributed Constrained Power Control (DCPC) algorithm su ers from an outage probability close to one, unless some counter-measures are taken. The time variant algorithm however, copes well with this situation and provides a close to an optimal scale up factor for the target Signal to Interference Ratio. Further, the time variant algorithm provides a substantial improvement in the spectrum capacity compared to the following algorithms: DCPC with a lower bound on the transmission power, xed transmission power, and constant received power control.