Research Of Spectrum Allocation Algorithm And Access Technology On Multi-radio Vanet

In recent years,Vehicular ad-hoc network (Vehicular Ad Hoc Network, VANET) as animportant foundation for intelligent transportation system (ITS) has become a hotspot of theresearch on engineering and academia at home and abroad.Under the environment of the need toguarantee network QoS(Quality of Service), the multi-channel communication technology forvehicle nodes equipped with multi-interface is present.The multi-radio VANET has characteristicsof high speed mobile nodes, rapid changes of the network topology,uneven distribution of nodesand channel interference.Research of wireless spectrum resource allocation and efficient mediumaccess control (MAC) protocol based on the VANET itself and requirements has important theoryvalue and practical significance.Spectrum allocation is responsible for the assigned to differentnode corresponding channel and eliminates the conflict between the communication link, andaccess control is responsible for avoiding conflict of different nodes in the access channel toachieve reasonable and efficient channel access. The research and improvement of multi-radioVANET Spectrum allocation and channel access has important academic significance andapplication value.This topic is mainly to study the spectrum allocation algorithm and the access controlmechanism of multi-radio multi-channel VANET. Firstly, as to the division of the on-boardcommunication channel by the FCC, analyzing the deficiency of common spectrum allocationalgorithm in VANET, This paper analysis the quality of channel,defined channel feedbackmatrix and the calculation method of each element in the channel feedback matrix is given on thebasis of Graph Coloring Model.The vehicle nodes could select available channel according to thevalues in channel feedback matrix,a dynamic spectrum allocation algorithm CFSA based onchannel feedback is proposed.Secondly,as to distribution channel for multi-radio communication,analyzing the challenges of channel access for multi-radio VANET, and consider the high loadnetwork characteristic caused by the multi-radio communication of all vehicles, using theadvantages of competitive channel access technology and TDMA technology, this paper proposesa channel access technology TCCA (Time-division Competition Channel Access) based on vehicleinterface status word.Then,on the basis of the above research，NS-2network simulation platform is established.Using the simulation platform, the proposed spectrum allocation algorithm andchannel access technology will be simulated and evaluated. Simulation results showed that CFSAalgorithm implements dynamic spectrum allocation in multi-radio VANET, reasonably solves theproblem of the unreasonable channel allocation, and significantly improves the performance of thenetwork. TCCA mechanism can improve the success rate of node competition, having a goodscalability.Finally, the article lists some issues should be solved and consummation, needs further tostudy, so as to lead to improvement direction for further research.