5th ACM International Workshop on Vehicular Ad Hoc Networks (VANET)

September 2008

J. Mittag, F. Schmidt-Eisenlohr, M. Killat, J. Härri, H. Hartenstein

The control of vehicles’ radio communication behavior to deal with the constrained available wireless bandwidth has been identified as a key challenge in VANETs. As an element of congestion control, this paper addresses distributed transmission power control as a means to control the impact of periodic transmissions (‘beacons’) on the overall channel load. By also considering recently discussed fairness issues, we first examine the trade-off between the effectiveness of controlling the channel load on the one hand and the corresponding costs in terms of the required packet overhead on the other hand. We provide insights to the underlying estimation problems and present a sensitivity analysis with respect to non-homogeneous vehicular traffic densities and non-perfect channel conditions. Second, based on the analysis, we propose a segment-based power adjustment approach based on a distributed vehicle density estimation. The approach put forward in this paper reduces overhead by two orders of magnitude compared to previous approaches while still being effective in controlling the channel load.

• Download pdf