Handover Parameter Optimization in WCDMA using Fuzzy Controlling

The increasing traffic and the demand for high data rate services in WCDMA networks prompt the need for an automatic network optimization. Current state-of-the-art optimization methods adapt physical parameters, such as the antennas´ tilt or azimuth. As agreed in the community, a further capacity increase can be achieved by an optimization of radio resource management (RRM) parameters. While theoretical approaches of RRM parameter optimization have already been introduced in the literature, practical solutions optimizing cell individual parameters have rarely been treated so far. Consequently, this paper copes with the optimization of the cell individual offset (CIO) in the soft handover algorithm with the goal to reduce the network´s outage probability. We design and apply a fuzzy logic controller, whose output are CIO changes matching the current traffic and load conditions. Verifications using a dynamic system simulator prove the powerfulness of our method and promise significant outage reductions in a fully loaded network scenario leading to capacity improvements of up to 9 %.