Beacon-Less Geographic Routing in Real Wireless Sensor Networks

Geographic Routing (GR) algorithms require nodes to periodically transmitHELLO messages to allow neighbors to know their positions (beaconingmechanism). Beacon-less routing algorithms have recently been proposedto reduce the control overheads due to these messages. However, existingbeacon-less algorithms have not considered realistic physical layers.Therefore, those algorithms cannot work properly in realistic scenarios.In this paper we present a new beacon-less routing protocol called BOSS.Its design is based on the conclusions of our open-field experimentsusing Tmote-sky sensors. BOSS is adapted to error-prone networks andincorporates a new mechanism to reduce collisions and duplicate messagesproduced during the selection of the next forwarder node. We compareBOSS with Beacon-Less Routing (BLR) and Contention-Based Forwarding(CBF) algorithms through extensive simulations. The results show thatour scheme is able to achieve almost perfect packet delivery ratio (likeBLR) while having a low bandwidth consumption (even lower than CBF).Additionally, we carried out an empirical evaluation in a real testbedthat shows the correctness of our simulation results.