Dead-reckoning for position-based forwarding on highways

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Dead-reckoning for position-based forwarding on highways

King, Thomas / Füßler, Holger / Transier, Matthias / Effelsberg, Wolfgang

Position-Based Forwarding (PBF), i.e. greedy position-based packet forwarding using a beaconing-induced neighbour table, suffers from an always-outdated perception of neighbour positions, especially at low beaconing rates. However, between beacon accuracy is likely to be improvable by the application of dead-reckoning strategies, the extrapolation of known position information. Especially in vehicular highway scenarios, where node movement is 'very one-dimensional' and changes of direction are impossible, extrapolation seems to be useful. In this paper the effects of dead-reckoning strategies on the between-beacon position accuracy will be studied. To do this, simulations have been carried out to investigate the impact of different dead-reckoning strategies on protocol performance and cost and we explain the trade-offs between them. The conclusion will be like this. In German highway scenarios, dead-reckoning enhanced PBF can achieve almost perfect packet delivery with beacon intervals of up to 6 seconds, whereas standard PBF loses a significant ratio of packets even at a beacon interval of 1 second. In general, the authors show results indicating that the application of dead-reckoning generates (a) less beaconing traffic with an equal or better perception of the neighbors' positions and (b) less overall transmission cost caused by frequent packet retransmissions when using the same beaconing frequencies.