VLS: A Map-Based Vehicle Location Service for City Environments

Location based routing protocols are often used to deliver packets in VANET for the sake of scalability and lower overhead. Before exchanging information between moving vehicles, the location of destination node should be discovered. However, the existing location service employed in MANET is not very suitable for vehicular ad hoc network. In this paper, a vehicle location service protocol (VLS) is proposed to support inter-vehicle communication (IVC) in cities. The information in digital maps is utilized to help realize location service. We present a method of partitioning the network and constructing distributed location servers, which can avoid selecting servers in void areas and decrease the average location discovery delay. In order to reduce the location update cost, forwarding trees and adaptive update policies are used to send messages. In addition, the cost of location update and discovery delay can be balanced through different parameters setting for a given network. Different scenarios are simulated to compare the performance of GLS, GHLS and VLS. The experiment results show that VLS outperforms others in urban environments.