PERFORMANCE EVALUATION OF SINGLE-HOP PERIODIC SAFETY BEACONING FOR VEHICLE-TO-VEHICLE COMMUNICATION IN V ANET

Saving human lives on road has become the prime objective of Vehicular Ad hoc
Network (VANET). In order to achieve safety, vehicles maintain neighborhood
awareness with the help of safety messages. Providing an efficient safety messaging
mechanism is a challenging task in V ANET, due to particular characteristics of
VANET, i.e. high mobility, limited channel bandwidth, very short communication
duration, and highly dynamic topology. In most of the safety messaging schemes
proposed so far, Periodic Safety Beacons (PSBs) are generally considered dispensable
in comparison with event-driven messages. However in reality, vehicle-to-vehicle
(V2V) PSBs are used to collect critical information required by all the safety
messaging schemes and cannot be dispensed. Thus, ensuring optimum QoS for V2V
single-hop PSBs is essential for achieving acceptable level of safety. However,
thorough performance evaluation ofV2V single-hop PSBs is yet to be carried out.
This research comprehensively investigates V2V single-hop periodic safety
beaconing in the light of tunable parameters i.e. Beacon Generation Interval (BGI),
Safety Beacon Size (SBS), and Communication Range (CR) that govern their
behavior. Results from exhaustive simulations show that adjusting tunable parameters
solely or combined does not fully satisfY the strict QoS criterion required for safety
applications. Overall, an acceptable level of end-to-end delay can be achieved by
dynamically adjusting tunable parameters with BGI > 1 OOms, but lower BGI is not
suitable with larger SBS. In dense traffic conditions strict PDR criterion of 99% is
never achieved beyond lOOm target CR. An exclusive comparison between tunable
parameters shows that solely adjusting BGI can attain relatively higher PDR than
other tunable parameters while SBS remains the least effective parameter. It is also
validated that dynamic adjustment of CR and BGI is necessary for optimal output in
terms of PDR. Furthermore, optimal combinations of tunable parameters for different
highway service levels with respect to safety application requirements are also
presented.