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—Recently proposed beaconless georouting algorithms are fully reactive, with nodes forwarding packets without prior knowledge of their neighbors. However, existing approaches for recovery from local minima can either not guarantee delivery or they require the exchange of complete neighborhood information. We describe two general methods that enable(More)
Beaconless georouting algorithms are fully reactive and work without prior knowledge of their neighbors. However, existing approaches can either not guarantee delivery or they require the exchange of complete neighborhood information. We describe two general methods for completely reactive face routing with guaranteed delivery. The Beaconless Forwarder(More)
—Beaconless or contention-based geographic routing algorithms forward packets towards a geographical destination reactively without the knowledge of the neighborhood. Such algorithms allow greedy forwarding, where only the next hop neighbor responds after a timer-based contention using only 3 messages (RTS, CTS and DATA) per forwarding step. However,(More)
We investigate distributed algorithms for mobile ad hoc networks for moving radio stations with adjustable transmission power in a worst case scenario. We consider two models to find a reasonable restriction on the worst-case mobility. In the pedestrian model we assume a maximum speed <i>v<sub>max</sub></i> of the radio stations, while in the vehicular(More)
We try to close the gap between theoretical investigations of wireless network topologies and realistic wireless environments. For point-to-point communication, we examine theoretically well-analyzed sparse graphs, i.e. the Yao-graph, the SparsY-graph, and the SymmY-graph. We present distributed algorithms that can be used to build up these graphs in time £(More)
We have developed TakaTuka, a Java Virtual Machine optimized for tiny embedded devices such as wireless sensor motes. TakaTuka 1 requires very little memory and processing power from the host device. This has been verified by successfully running TakaTuka on four different mote platforms. The focus of this paper is TakaTuka's optimization of program memory(More)
We present a strategy for organizing the communication in wireless ad hoc networks based on a cell structure. We use the unit disk graph model and assume positioning capabilities for all nodes. The cell structure is an abstract view on the network and represents regions where nodes reside (node cells), regions that can be used for the communication flow(More)
A spanner is a subgraph of a given graph that supports the original graph's shortest path lengths up to a constant factor. Planar spanners and their distributed construction are of particular interest for geographic routing, which is an efficient localized routing scheme for wireless ad hoc and sensor networks. Planarity of the network graph is a key(More)