Routing Strategies for Quality of Service Optimization over Vehicular Ad Hoc Networks: A Review

The evolution in the field of telecommunication, networking, Internet of Things and mobile communication technologies has resulted in various real-time applications in which smart cities equipped with Intelligent Transport System (ITS) is one of the instances. In recent times the ITS has gained significance in the smart city development. The ITS uses the vehicular ad hoc networks (VANET) that exhibits three major qualities firstly the mobility of nodes at high rate, secondly dynamic change of network topology and thirdly fragmentation of communication links or network. The real-time applications of VANETs will require to meet various quality of services (QoS) parameters. There are various QoS-based routing protocols that have already been proposed to house applications with QoS requirements. This paper focuses on comparing various strategies of QoS-based routing in VANETs. The comparison is made among different strategies used to enhance various QoS parameters, namely bandwidth, jitter, packet delivery ratio (PDR), throughput and latency. We also look at different mobility models and modeling methods that can be used to test VANETs. Lastly, we list out the research challenges in the area of VANETs which still requires considerable efforts for their improvement.