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Top1 Introduction
Vehicle-to-Everything communications or V2X communications permit the exchange of information between vehicles and between a vehicle and network infrastructures. The goal of V2X communications is to enhance road safety, augment traffic efficiency, reduce environmental impacts and supply additional information services to travelers.
V2X communications, as presented in figure 1, include diverse types such as: Vehicle to Vehicle (V2V), Vehicle-to-Pedestrian (V2P), Vehicle to Infrastructure (V2I), and Vehicle-to-Network (V2N) , (2018). V2V communication is mainly done between nearby vehicles exchanging information on location, speed, and direction to avoid accidents. V2P transmission covers communication between a vehicle and a road user (a pedestrian or a cyclist). V2I communication takes place between a vehicle and the road infrastructure, called RSU (Road-Side Unit). V2N communication takes place between a vehicle and a V2X application server via a 4G/5G network.
V2X communication requires low latency, high-speed and ultra-reliable transmission. V2X applications include security applications and non-security-related applications. Security applications include driver assistance and road hazard warning applications. Non-security applications include road traffic management applications, remote vehicle diagnostics, air pollution monitoring, comfort and entertainment, (2018).
Security-related applications provide vehicle drivers with information about various hazards and situations that they usually cannot see. These applications require high reliability and low latency for high-speed message transfer. Examples of security-related applications are collision, loss of control, lane change warnings, and vulnerable road user safety applications.
Efficiency and traffic management applications aim to improve traffic management on the roads by providing road traffic assistance to the users. These applications require high reliability and longer latency requirements for high-speed message transfer. A vehicle or RSU collects information about traffic conditions. Then it transmits it to other vehicles allowing them to choose a different route, which optimizes travel time. Examples of traffic management applications are speed management (e.g., regulatory speed limit pop-up notification and green light speed notification) and cooperative navigation.
Entertainment and custom applications are ancillary applications and comfort use cases, which demand high data rates and flexible communication types. These applications can help extend internet access to the moving vehicle so that passengers can continue to work while on the move. Passengers can also access various applications, namely the web, Voice over IP (VoIP), video, online games, and navigation and location applications. Examples include infotainment and route planning.
In this work, our focus is on identifying a solution to the problem of mobility management for V2X communications in future vehicular networks. Indeed, the highly mobile feature of vehicles and varying network densities increase the number of handovers. This situation can lead to a significant accumulation of unnecessary handovers (Ping-Pong effects). In addition, it increases the risk of handover failure and handover delay.
We present a solution to optimize the handover procedure in next-generation vehicular networks. Our approach adopts a new technique of clustering vehicles according to their mobility profile. The vehicles in each cluster communicate with each other using LTE PC5 technology and are also connected to the cluster head via the multi-hop relay method. We have adapted the vehicle clustering and multi-hop relay methods to avoid frequent and unnecessary handovers between the base station and the vehicles. Also, the new approach introduces an SDN-based handover management mechanism. This novel mechanism allows vehicles to select the most optimal network for V2X communications based on various parameters.