This paper proposes a new framework for future policy-based adaptive vertical handover (VHO) in heterogeneous wireless networks. In contrast to existing, statically configured, schemes that lack the ability to quickly adapt to changing network loads, the proposed framework continuously derives optimal configuration policies with respect to handover initiation and network selection. To achieve this goal, the proposed work relies on the interactions between two components: a policy-based real-time simulator and a VHO manager. Triggered by indications of VHO performance degradation, the former enacts a set of VHO scenarios, selected based on a predefined set of simulation policies, to evaluate possible new VHO configurations before actually applying them to the real network. Based on the outcome of the simulation and the monitored network performance, a set of VHO configuration policies is communicated to the VHO manager to reconfigure and/or fine-tune the running VHO scheme. Preliminary performance evaluation results demonstrate the significant enhancement of the outcome of the proposed VHO framework in terms of reducing the ping-pong phenomenon and the handover delay.Index Terms-4G wireless networks; vertical handover; policybased management; run-time simulation.