Abstract
The main goal of Vehicular Ad Hoc Networks (VANETs) is to improve driving safety. However, VANETs may not guarantee timely detection of dangerous road conditions or maintain communication connectivity when the network density is low, which may pose a risk to driving safety. Towards addressing this problem, the VANET is integrated with the inexpensive Wireless Sensor Network (WSN). Sensor nodes are deployed along the roadside to sense road conditions, and to buffer and deliver information about dangerous conditions to vehicles regardless of the density or connectivity of the VANET. The most challenging features in VANETs are their dynamic topology and mobility, where vehicles are moving at variable and high speeds and in different trajectories. In contrast, the challenge in the WSN is in managing the limited energy resources of the nodes, since the performance of WSNs strongly depends on their lifetime. Thus, the fundamental design challenge in designing routing protocols for a hybrid network of VANETWSN is to maximize network lifetime and connectivity, and to minimize delay and energy consumption. To overcome these challenges, this research investigates the effects of different Quality of Service (QoS) parameters on forwarding decisions in an efficient distributed position based routing protocol, and focuses on bandwidth estimation. Bandwidth estimation is of great importance to network Quality of Service assurance, network load balancing, and routing. In this research, a bandwidth estimation strategy based on normalized throughput of a link, taking into account the interference and packet loss ratio in discrete time for every successfully delivered packet is proposed for a hybrid network of VANET-WSN. The simulation results show that the strategy is effective, and can accurately estimate the bandwidth of VANET-WSN. A comprehensive performance analysis in representative urban scenarios is performed that takes into account realistic propagation models and real city scenario traffic. (C) 2017 Elsevier B.V. All rights reserved.