Many research work is going on in the domain of pure ad-hoc networking and even more issues are raised due to the missing central infrastructure to properly manage resources, guarantee fairness, and provide security features. On the other hand lot of research effort is spent to increase the performance of infrastructure-based access networks to cope with the steadily increasing demand for broadband data. When making a step back, the most promising evolution of heterogeneous networking is the integration of both paradigms. Taking advantage of the well controlled cellular environment and the high capacity of ad-hoc and direct node-to-node communication. The resulting hybrid networks are incorporating the best of both worlds. The concept of
Cellular Assisted Heterogeneous Networking
(CAHN) provides a framework to offer convenient and secure management of heterogeneous end-to-end sessions between nodes. The introduced separation of the signaling and the data plane allows to switch on power demanding broadband interfaces like GPRS, UMTS, or even WLAN only, if actually required, i.e., data has to be sent or received. The proposed out-of-band signaling enables furthermore the integration of ad-hoc links to offer best performance whenever nodes are within vicinity. Extensive simulations show that both, the integration of ad-hoc links and the selective activation of high power broadband interfaces, can significantly increase the performance of heterogeneous networks.