QoE-Driven and Traffic-Flow-Density-Based Link Scheduling Algorithm in LLC Protocol for HetVNETs

In order to satisfy the requirements of the variety of network applications and the convergence between network physical media in heterogeneous network, a new link scheduling algorithm based on priority of data, link status and traffic flow density(Priority, Delay and Load Link Scheduling Algorithm, PTLCSA) is proposed by improving traditional data-link layer protocol in Vehicular Ad Hoc Network(VANET). At first, based on the four types of vehicle data in vehicle networking standard, data priority is proposed to indicate the sending weight of different data. Meanwhile, delay factor and load factor are proposed to evaluate link status in real time. Then, based on data priority, delay factor, load factor and traffic flow density, data priority matching degree (DPMD) of link is proposed, and according to Pareto optimal, the upper bound of non-WSM (non-WAVE Short Message, non-safety messages) maximal distribution frequency about IEEE 802.11p link is presented, which provide theoretical foundation for data frames to select links. And then, based on DPMD and the upper bound of non-WSM maximal distribution frequency, PTLCSA is designed and realized, and the time complexity of PTLCSA is analyzed in this paper. Finally, simulation results show that on the premise that satisfying the Quality of Experience(QoE) of most network applications, PTLCSA can reduce the delay of security applications and improve the utilization ratio of links.