Role of directional wireless communication in vehicular networks

Abstract

Enabling safety in vehicles is an ongoing challenge for the automotive sector. One approach towards enhancing safety is to increase knowledge within a vehicle of the actions of vehicles in the vicinity. Increased awareness is essential for activating the safety systems to take evasive or precautionary actions in the event of an incident. Wireless radio communication has emerged as a key enabler for exchanging safety information. Several initiatives across the world have considered various radio communication technologies to implement safety communication. However, there are significant constraints to utilizing wireless radio communication. In this article, we discuss briefly the challenges in enabling safety communication with wireless radio in the context of vehicular networks. We introduce the on-going work in utilizing free space optical communications as an enabler for inter-vehicle safety communication. As a first step, we compare with the current 802.11 standard implementation for achievable performance. Given that the two technologies are inherently different, directional versus omni-directional, we seek to identify the scenarios where each technology is best suited. Particularly, we compare packet delivery ratio (PDR), throughput and average packet delay of the two enabling technologies, under assumptions, in the context of increasing vehicle traffic density. Our results demonstrate that a directional technology such as free-space optics is less susceptible to contention scenarios. As a result, the performance in high density scenarios is better than that can be achieved from using omni-directional long-range technologies such as 802.11. * In Proc. IEEE Intelligent Vehicles Symposium (IV '10), San Diego, CA. June, 2010.

Investigation of vehicle to vehicle communication system using visible light technology

“…The system uses short-range directional optical transceivers to share vehicle state data. Also, they performed a comparative analysis between omnidirectional 802.11 RF communications and directional VLC, with application in vehicular communications is presented in [24]. The results show that in high traffic density, VLC offers better performances in terms of packet delivery ratio, throughput, and average packet delay, at the cost of a shorter communication range [25].…”

Visible light communications cooperative architecture for the intelligent transportation system

“…In order to enable V2V and V2I communications several technologies have been proposed and explored: 802.11 (Wi-Fi) [5], Bluetooth [6], VLC [7]. V2V communications based on RF are very likely to present severe collisions in high traffic density, when multiple vehicles use the same medium [8,9], and this leads to unaccepted latencies for a reliable safety application, which require latencies less than 100 ms [10]. Furthermore, the radiofrequency channels are often saturated and the extension of new available carriers is expensive or even impossible.…”

Free space optical communication in the visible bandwidth for V2V safety critical protocols

“…To overcome this problem, directional antennas are being considered [7] together with Free Space Optics (Infra-Red and Visible Light based) [8]. These technologies will be considerably important for safety-critical applications whenever a prompt and well-addressed alert signal must be delivered to a neighbor car (just) in time for triggering an action by its electronic brake or steering systems.…”