Abstract
In recent years, vehicles are becoming safer and more driver-friendly thanks to the advancements in sensing technology and wireless communications. Vehicular Sensor Networks and Vehicular Ad hoc Networks (VeSANs) play a critical role to ensure prompt delivery of real-time sensing data for processing. Within a vehicle, various types of on-board sensors produce significant amount of real-time sensing data, and these data require an efficient and robust vehicular sensor network to transport. Communications also exist among vehicles. Some sensing data such as speed may be exchanged among vehicles to produce timely and meaningful traffic information. Vehicles may also communicate with other roadside infrastructures such as parking and shopping facility to obtain relevant information. Huge information is exchanged and processed in the network. A practical and robust design of VeSANs is essential to facilitate these emerging vehicular social applications. To accelerate the adoption of these new emerging techniques, a number of important issues must be addressed such as the routing and security of VeSANs and applications. In this special issue on vehicular networking, we have invited a few papers that address such issues.
Several papers proposed methods to deal with routing protocols in the vehicular ad hoc network (VANET). The paper entitled “An Efficient Prediction-Based Data Forwarding Strategy in Vehicular Ad Hoc Network” introduces a new metric named link utility used in the process of forwarder selection to improve data forwarding efficiency in VANET. The paper entitled “Distance-Based Stable Routing Decision Scheme in Urban Vehicular Ad Hoc Networks” applies distance-based routing to packet-collisions avoidance scheme in the intersection in order to stabilize route decision scheme based on the adaptive waiting time. The paper entitled “Connectivity-Sensed Routing Protocol for Vehicular Ad Hoc Networks: Analysis and Design” utilizes vehicle distribution information collected by intersection infrastructure to help vehicles select a path along a road with not only better progression to destination but also better network connectivity. The paper entitled “A Survey of Multicast Routing Protocols for Vehicular Ad Hoc Networks” provides a comprehensive review on important VANET multicast routing protocols and classifies them into geocast and cluster-based categories based on the approaches and techniques used in these protocols.
Several other papers addressed clustering and information service in the network. The paper entitled “Self-Organized Clustering Architecture for Vehicular Ad Hoc Networks” uses clusters in VANETs to optimize communications in situations with high road traffic density by establishing a virtual backbone of the network. It also permits use of secret-key cryptography for more efficient intracluster information exchanges. The paper entitled “An Efficient Downloading Service of Large Popular Files in VANET Based on 802.11p Protocol” proposes a multiple-access downloading scheme, including vehicles downloading files from road side units directly, vehicles downloading files through forwarding vehicles, and vehicles downloading files through V2V communications. Additionally, it adopts the content naming schemes used in information centric network (ICN) to improve data retrieval and matching speed. The paper entitled “Towards Independency Using LMN4DISABLED System for Disabled” proposes a localizing, monitoring, and navigating system for people with physical (noncognitive) disabilities such as the blind or wheelchair-bound. Sensor nodes and cameras are scattered in the hallways and at each room in the building. Smartphone devices are used as interfaces for the disabled people to communicate with the surrounding environments.