## 1 Introduction  
The research interest in Visible Light Communication (VLC) has been boosted since its acceptance by the IEEE 802.15.7 standard to utilize VLC for the Physical (PHY) and Medium Access Control (MAC) layers [1] of the free-space optics systems. The increasing amount of unmanned vehicles is reshaping the major fields of life including business, rescue operations and everyday commutes. The significant development of smart societies has created new opportunities in the ever changing world of communication systems. The humanitarian sector is still in search of a feasible framework for smart transportation to provide logistical and health care services [2], on an everywhere-and-anywhere basis. The need to provide a high level of service, while considering smart transportation's environmental impact and government policy measures [3], has led to the use of innovative solutions of devices and optimization algorithms [4] in the past decade. VLC systems based on the Light Emitting Diode (LED) provide a suitable projection towards the realization of such systems on a large-scale, as they can make use of the existing lightening frameworks to offer considerably high data rate communication. The associated advantages include low cost, immunity from Electro-Magnetic (EM) interference, unlicensed band operation and several special applications where EM waves can not be used (such as underwater communications) [5]. VLC-based Light-Fidelity (LiFi) systems [6] are another example where the existing facilities of visible light can be utilized to provide broadband services at bus stops, train stations, waiting areas at hospitals, etc. For instance, LED operated billboards on a high street can provide network access without the need for a separate Wireless-Fidelity (wifi) network. Due to its ease of implementation, VLC is equally useful for inter and intra vehicle communication, as many safety features such as cruise control can be activated in a rear vehicle by transmitting the information from a front one [7]. The importance of research on VLC-based systems has upsurged in the past decade due to the saturation of the radio frequency (RF) spectrum, drastic demand in the number of connected devices, increasing interference levels and environmental constraints of wireless power levels. However, the industrial development of VLC-based systems has not been impressive so far due to the insufficient work on system modeling and analysis, while considering the practical impacts and factors affecting the system performance. Most of the study on VLC so far has been performed for indoor environments [8; 9; 10] and the real challenge for such systems is the change in intensity of light in the case of outdoor transmission deteriorating the system's performance to a large extent [11]. State-of-the-art technologies such as intelligent transportation systems (ITS) require both indoor and outdoor communication access [12], and the issues related to the development of such systems on the required scale needs to be addressed. LEDs are commonly found in the form of arrays due to their low cost, high energy efficiency and long lifetime. Although LED supports bandwidths of up to a few Megahertz (MHz), their existence in the form of vehicular lights, lamp posts, traffic lights and billboards makes them a potential candidate to be used for ITS [13], as compared to other optical sources. The current road situation, possible queues, and information about the pedestrians or cyclists moving towards the road from a street, can be transmitted to the vehicles using existing infrastructure, supported by the conventional optical networks for mobile networks [14]. As the Line-of-Sight (LoS) and visible nature of LED-based communication are considered as distinguished advantages of this technology over RF counterparts [15; 16; 17], the provision of reliable transmission even for small data rates is still in question.