  In this work, we present a new approach for competitive geometric routing in
wireless ad hoc networks. In general, it is well-known that any online routing
strategy performs very poor in the worst case. The main difficulty are
uncovered regions within the wireless ad hoc network, which we denote as radio
holes. Complex shapes of radio holes, for example zig-zag-shapes, make local
geometric routing even more difficult, i.e., forwarded messages in direction to
the destination might get stuck in a dead end or are routed along very long
detours, when there is no knowledge about the ad hoc network. To obtain
knowledge about the position and shape of radio holes, we make use of a hybrid
network approach. This approach assumes that we can not just make use of the ad
hoc network but also of some cellular infrastructure, which is used to gather
knowledge about the underlying ad hoc network. Communication via the cellular
infrastructure incurs costs as cell phone providers are involved. Therefore, we
use the cellular infrastructure only to compute routing paths in the ad hoc
network. The actual data transmission takes place in the ad hoc network. In
order to find good routing paths we aim at computing an abstraction of the ad
hoc network in which radio holes are abstracted by bounding boxes. The
advantage of bounding boxes as hole abstraction is that we only have to
consider a constant number of nodes per hole. We prove that bounding boxes are
a suitable hole abstraction that allows us to find $c$-competitive paths in the
ad hoc network in case of non-intersecting bounding boxes. In case of
intersecting bounding boxes, we show via simulations that our routing strategy
significantly outperforms the so far best online routing strategies for
wireless ad hoc networks. Finally, we also present a routing strategy that is
$c$-competitive in case of pairwise intersecting bounding boxes.
