Role of directional wireless communication in vehicular networks

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.