A Hybrid V2X System for Safety-Critical Applications in VANET

Vehicular Ad-hoc Networks (VANETs) using a connected-car technology can support safety-critical applications in Cooperative Intelligent Transportation Systems (C-ITS). While WAVE/DSRC has been investigated by a number of researchers to support VANETs, it may not be easy to distribute WAVE/DSRC in the near future due to several practical obstacles. In this paper, we discuss an alternative to support V2X communication without using WAVE/DSRC. Therefore, we propose a novel hybrid system which incorporates a flexible mix of a cellular network and Wi-Fi Direct. Especially, to offload cellular traffic and alleviate additional cost, Wi-Fi Direct is used as a subsidiary method to enable communication by using local links without the help of infrastructure. Our proposed system provides 1) seamless connectivity and monitoring vehicles through a cellular network, 2) local data transmission through Wi-Fi Direct, and 3) solutions for reducing long connection establishment time of Wi-Fi Direct. The performance of the proposed system is evaluated in terms of the total discovery time and data usage in several scenarios in a real driving environment. Our preliminary results show a possibility of a smart mobile device-based approach for V2X communication.