A Connectivity-based Strategy for Roadside Units Placement in Vehicular Ad Hoc Networks

In urban scenario, the imbalanced spatial distribution of traffic flow exerts an important influence on the performance of communication between vehicles and the Roadside Unit (RSU). This paper presents a strategy for RSUs placement based on the road traffic characteristics, aiming at improving connectivity in vehicular ad hoc networks. To divide the coverage area of each RSU, we propose an Expansion and Coloration Algorithm (ECA). The average connectivity model for all vehicles in the network is established based on the results obtained from ECA. The RSUs placement problem is formulated as a combinatorial optimization problem, of which the objective is to maximize the average connectivity probability by searching for an optimal position combination of the given RSUs. Taking part of an actual urban road network as an example, the RSUs placement problem is calculated and the optimal placement scheme is evaluated. Simulation results show that the optimal placement scheme obtained from our strategy leads to the best connectivity compared to uniform placement and hot-spot placement.