Soft handover overhead control in pilot power management in WCDMA networks

In WCDMA networks, common pilot channel (CPICH) signals are used by mobile terminals for channel quality estimation, cell selection, and handover. The strength of the CPICH signal determines the coverage area of the cell, impacts the network capacity, and thereby the quality of service, and is therefore a crucial parameter in network planning and optimization. The more power is spent for pilot signals, the better coverage is obtained. On the other hand, a higher value of the pilot power level in a cell means higher pilot pollution in the network and less power available to serve user traffic in the cell. In this paper, we present a model for pilot power optimization that allows us to study the effect of various soft(-er) handover (SHO) probability and coverage degree levels on pilot power consumption and SHO overhead in the network. We report our numerical experiments for a WCDMA network based on a planning scenario for the city of Berlin.