دانلود رایگان مقاله ارتباطات نور مرئی به عنوان یک تکنولوژی مکمل برای اینترنت حامل

Abstract

The paradigm of connected vehicles is moving from research to implementation, thus enabling new applications that start from safety improvement and widen to the so called Internet of vehicles (IoV). The candidate enabling technologies in the radio frequency (RF) bands are cellular and short range technologies. However, the limited bandwidth shared among several applications pushes researchers to look at new technological solutions. To this end, an option is provided by visible light communication (VLC). Based on the use of the light emission diodes (LEDs) that are already available on the majority of vehicles, VLC would enable short range communication in large, unlicensed, and uncongested bands with limited costs. In this work we first highlight the main properties of VLC in vehicular networks and revise the state of the art focusing on both the IEEE 802.15.7 standard and on the performance demonstrated by field tests that have been conducted worldwide. Then, we discuss the limitations of using VLC for pure vehicular visible light networks (VVLNs) and its application as complementary technology, to be implemented with other wireless standards in future heterogeneous vehicular networks. Finally, we show numerical results provided by simulations in a realistic urban scenario focusing, as a case study, on the crowd sensing vehicular network application with VLC added to short range IEEE 802.11p technology. Results demonstrate that the addition of VLC improves the performance of a conventional vehicular network based only on IEEE 802.11p.

5. Conclusion

This paper focused on the adoption of VLC as supplementary technology to the RF ones for data exchanging between vehicles and between vehicles and RSUs in vehicular networks. We proposed to exploit this emergent technology in cooperation with DSRC and cellular communications to increase the overall resources available for the future IoV. Example results have been shown focusing on the crowd sensing vehicular network application, considering VLC in addition to DSRC. A cooperative algorithm to adaptively select the technology has been also proposed, with a single parameter allowing to move from VLC always preferred to DSRC to the opposite case. Simulations, performed in realistic urban scenarios with hundred of vehicles, demonstrated the significant improvement obtained by adding VLC to DSRC. The best results were obtained by giving priority to DSRC when its channel is far from congested, and preferring VLC in the other cases.