Performance Study of Threshold Variations in Temporal Decision Systems for Routing in Vehicular Ad hoc Networks

Problem statement: Route maintenance and re-discovery are expensive in signaling and computation for routing in Vehicular Ad hoc Networks (VANETs). Hence it was desirable to choose the optimal route during the route selection phase. Approach: In this study, the threshold-based routing protocol β-wt uses the notion of threshold from variable precision rough sets. This protocol was used to evaluate routing performance on freeway scenarios in VANETs. A Traffic Generator tool IMPORTANT was used to obtain vehicular movement traces, that are then given as input to the Network Simulator NS2. Results: Results of four performance metrics were got for different values of the thresholds. The performance of the new protocol was compared with that of the original Dynamic Source Routing (DSR). Conclusion: The new protocol performs better than DSR in Packet Delivery Ratio (PDR) and Normalized Routing Load (NRL). The study showed that variations in thresholds do not affect PDR and NRL, while for End to End Delay (EED) and Average Hop Count (AHC), certain values of these thresholds perform much better than other values in this particular VANET application.