Study And Design Of Multi-LLC Mechanism Based On Convergence Of Heterogeneous Networks On VANET

Vehicular Ad Hoc Networks(VANET)is a message switching network including vehicle terminals,infrastructures and Road-Side Units,which is used to communicate between vehicle to vehicle,vehicle to infrastructure and vehicle to Road-Side Unit,and is considered as a effective solution to solve the urban traffic problems.Related organizations have proposed some protocol standards based on VANET,and one of them,Wireless Access in Vehicular Environment(WAVE),is commonly accepted.With the development of VANET,the requirement for VANET services of users is higher and higher.Because of the limitation of single wireless access technology,researchers integrate multiple wireless access technologies to build VANET by using heterogeneous network convergence technology based on WAVE protocol standard,to improve the robustness and reliability of VANET,and satisfy the increasing network requirements.In order to satisfy the requirements of the variety of network applications and the convergence between network physical media in VANET,this paper proposed a new link scheduling algorithm based on priority of data frame,link status and traffic flow density called HetVNETs Link Scheduling Algorithm in LLC(HetLLCA)through improving traditional data-link layer protocol in VANET.At first,based on the four types of vehicle data in vehicle networking standard,data frame priority was proposed to indicate the sending weight of different data frames.Meanwhile,delay factor and load factor were 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 links was proposed,and according to Pareto optimal,the upper bound of non-WSM maximal dispense frequency about IEEE 802.11 p link was presented,which provide theoretical foundation for data frames to choose links.And then,based on DPMD and the upper bound of non-WSM maximal dispense frequency,this paper designed and realized HetLLCA,and analyzed the time complexity of HetLLCA,which is O(n).Finally,simulation results showed that under the premise that satisfying the QoE of most network applications,HetLLCA reduces the delay of security applications and improves the utilization ratio of links.Due to the complex application requirements in the VANET,the use of multiple network access methods to improve network performance has become the main trend today.But at the same time,the phenomenon of packet reordering is more serious.Therefore,according to the vehicle networking protocol standards,this paper proposes a link layer scheduling algorithm based on data priority,link status,and data continuity.that according to the vehicle networking protocol standards,First,the data priority is defined according to the four access categories defined in the WAVE Standard,and the delay factor and load factor are defined to evaluate the link status and the popularity to describe the continuity of the data.Then,using Pareto optimality,the maximum frequency of WSM distribution in 802.11 p links is given.The algorithm distribute data frames according to parameters such as data priority,delay factor,load factor,and popularity,and according to Pareto optimization.distribution.Finally,simulation experiments show that the algorithm can reduce the transmission delay of secure applications and reduce the occurrence of out-of-order data frames while ensuring the quality of experience(QoE).