Massive sales of smartphones and tablets have enabled more people to access the internet with a 3G connection than ever before. Predictions indicate an exponential growth of mobile data traffic world-wide reaching 6.3 exabytes per month by 2015, a 26-fold increase over 2010. Unfortunately, the current infrastructure will not be able to meet these demands. Already now, a speed reduction or even lack of connection can be noticed in crowded places. Service providers are addressing the problem by deploying Femtocells and Wi-Fi Access Points (APs) around cities. However, due to their limited connection range, the projected redirected traffic, including free APs at home and office, is expected to be only 39% by 2015. The intention of this thesis is to extend the range of Wi-Fi APs as internet gateways through multi hopping. Furthermore, phone calls and data exchange between devices in proximity are supported and also offloaded from the 3G data network. Therefore, we offload part of the traffic from the mobile data network to Wi-Fi. An added benefit is a reduction in energy consumption. However, current Mobile Ad-hoc Network (MANET) techniques are unable to scale or to handle high mobility. Therefore, we propose a novel approach called “Mobile Assisted Ad-hoc Networking”. MASS-ANET can be applied to any kind of mobile ad-hoc network where nodes can use both a global and a local transmission link. In this project, Wi-Fi local connectivity is used to create a mobile ad-hoc network. 3G links act as a global coordination medium with the help of a central server. The feasibility of the MASS-ANET is determined with the help of simulations. Subsequently modern commodity smartphones are used as prototypes in validation experiments. The proposed solution is verified using a real-world application: exchanging real-time voice traffic over several hops in a mobile ad-hoc Wi-Fi network.