دانلود رایگان مقاله تحرک و اتصال در شبکه خودرویی بزرگراه

Abstract

The performance of protocols and architectures for upcoming vehicular networks is commonly investigated by means of computer simulations, due to the excessive cost and complexity of large-scale experiments. Dependable and reproducible simulations are thus paramount to a proper evaluation of vehicular networking solutions. Yet, we lack today a reference dataset of vehicular mobility scenarios that are realistic, publicly available, heterogeneous, and that can be used for networking simulations straightaway. In this paper, we contribute to the endeavor of developing such a reference dataset, and present original synthetic traces that are generated from high-resolution real-world traffic counts. They describe road traffic in quasi-stationary state on three highways near Madrid, Spain, for different time-spans of several working days. To assess the potential impact of the traces on networking studies, we carry out a comprehensive analysis of the vehicular network topology they yield. Our results highlight the significant variability of the vehicular connectivity over time and space, and its invariant correlation with the vehicular density. We also underpin the dramatic influence of the communication range on the network fragmentation, availability, and stability, in all of the scenarios we consider.

7. Conclusions and open issues

In this paper, we employed fine-grained road traffic counts collected on real- world highways in proximity of Madrid, Spain, to generate synthetic traces of vehicular mobility along those road segments. An original approach to the parameterization of well-known microscopic vehicular mobility models allowed us to obtain realistic descriptions of quasi-stationary unidirectional traffic in heterogeneous conditions, including different highways, weekdays and measurement hours. These traces are publicly available and, to the best of our knowledge, represent the current state of the art in highway traffic datasets for networking studies. We carried out a comprehensive topological analysis on the mobility traces, confirming that: (i) the communication range and the vehicular density are the factors that primarily control the connectivity of highway vehicular networks; (ii) vehicular networks are not small-world or scale-free in nature. In addition, we unveiled the three-phase dependence of connectivity on network size, and its potential general validity across highway scenarios. We also quantified for the first time the actual availability and stability of the system.