The objective of vehicular communication is to improve road safety and traffic efficiency through a variety of cooperative intelligent transport system (C-ITS) services. These services allow information exchange between vehicles and other communication entities (e.g., vehicles, infrastructure, pedestrians). Many advanced services are envisaged to support autonomous vehicles and safety applications. The performance requirements of such services are considered highly critical for road safety. However, all these services increase the channel load, and thus, it is difficult to differentiate which service has a higher priority for accessing communication channels. In this paper, we focus on the classification of C-ITS services, which allows the cohabitation of all services considering the strict performance requirements for some services. The aim is to classify C-ITS services based on their packet delay requirements in order to define higher priority for critical services to ensure their dissemination, especially under congestion conditions. Then, we present protocols and quality of service (QoS) mechanisms that can map this classification to the available vehicular networks. INDEX TERMSCooperative Intelligent Transport Systems (C-ITS), Vehicular and wireless technologies, Cellular-V2X, ITS-G5, Vehicle-to-Everything (V2X)

To manage a growing number of users and an ever-increasing demand for bandwidth, future 5th Generation (5G) cellular networks will combine different radio access technologies (cellular, satellite, and WiFi, among others) and different types of equipment (pico-cells, femto-cells, small-cells, macro-cells, etc.). Multi-connectivity is an emerging paradigm aiming to leverage this heterogeneous architecture. To achieve this, multi-connectivity proposes to enable UE to simultaneously use component carriers from different and heterogeneous network nodes: base stations, WiFi access points, etc. This could offer many benefits in terms of quality of service, energy efficiency, fairness, mobility, and spectrum and interference management. Therefore, this survey aims to present an overview of multi-connectivity in 5G networks and beyond. To do so, a comprehensive review of existing standards and enabling technologies is proposed. Then, a taxonomy is defined to classify the different elements characterizing multi-connectivity in 5G and future networks. Thereafter, existing research works using multi-connectivity to improve the quality of service, energy efficiency, fairness, mobility management, and spectrum and interference management are analyzed and compared. In addition, lessons common to these different contexts are presented. Finally, open challenges for multi-connectivity in 5G networks and beyond are discussed.

The next generation mobile system is expected to support the continuous increase of users requirements. Through the high flow rates of these networks, new applications constraints are more complex and may be change dynamically and rapidly for wireless systems. The service heterogeneity provided by these applications has a great influence on system performance in terms of ability, availability and the context aware provided to make handover decision. To facilitate the negotiation process between the user and the network, we define some class of service that guarantees QoS for interworking between 3GPP and non-3GPP networks and the critical context criteria which influence the handover decision. In this context, our proposed approach supports the interaction between context-aware and class of service considering the use of the particular features of each class of service to make handover decision and providing the application required QoS. In this paper we conceive a new approach, called Enhance Simple Additive Weighting, for network selection that reduces computational complexity, the handover latency and eliminates networks which do not satisfy a minimum requirement compared to other existing approaches based on AHP strategy.

With the growing importance of cooperative intelligent transport systems (C-ITS), 3GPP has standardized LTE-V2X (Long Term Evolution -Vehicle-to-everything) in Release 14 to address specifically vehicle-to-everything (V2X) connectivity. This standard introduces a mode 4 in which vehicles allocate radio resources autonomously without cellular infrastructure support for direct vehicle-to-vehicle (V2V) communications. However, as LTE-V2X is a recent technology (compared to WAVE and ITS-G5), it is not sufficiently evaluated in the literature. In this work, we propose an evaluation of LTE-V2X mode 4 performances considering the impact of the sensing-based resource allocation mechanism parameters, the traffic load and the Quality of service (QoS) mechanism. In addition, we propose a comparative study of LTE-V2X mode 4 with ITS-G5. Based on several simulation scenarios from 3GPP, we prove that the Sensing-based SPS mechanism parameters and the traffic load significantly impact on the performance offered by LTE-V2X. In addition, we show that the QoS mechanism of LTE-V2X outperforms the ITS-G5 one in realistic multi-application context.

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