Reconfigurable system is a promising alternative to deliver both flexibility and performance at the same time. New reconfigurable technologies and technologydependent tools have been developed, but a system-level design methodology to support system analysis and fast design space exploration is missing. In this paper, we present a SystemC-based system-level design approach. The main focuses are the resource estimation to support system analysis and reconfiguration modeling for fast performance simulation. The approach was applied in a real design case of a WCDMA detector on a commercially available reconfigurable platform. The runtime reconfiguration was used and the design showed 40% area saving when compared to a functionally equivalent fixed system and 30 times better in processing time when compared to a functionally equivalent pure software design.