This thesis deals with planning and optimization methods as well as performance analyses for hybrid cellular and broadcasting networks. In this context, the considered systems are the cellular Universal Mobile Telecommunications System (UMTS) and the mobile broadcast Digital Video Broadcasting - Handheld (DVB-H) system. The combination of these two systems enables the advantages offered by both technologies to be exploited. On the one hand, interactive channels and seamless coverage are provided by the cellular network component. On the other hand, the additional high data rate broadcast downlink can be used to efficiently serve a large number of users at the same time. Thus, hybrid networks provide an efficient possibility for network operators to serve traffic demand with popular content. Due to the broadcast capability and the high downlink data rate, hybrid networks are particularly efficient when deployed in areas with high traffic demand. The IP Datacast framework offers the required basis for such inter-system cooperations.