Research Of Channel Allocation Algorithm And Access Technology On Multi-Radio Vanet

Vehicular ad-hoc network (Vehicular Ad Hoc Network, VANET) as an important foundation for intelligent transportation system (ITS), whose network topology changes frequently and communication link has a short survival time. Under the environment of the need to guarantee network QoS(Quality of Service), the multi-channel communication technology for vehicle nodes equipped with multi-interface is present, it is becoming a hot spot of research. An efficient and reliable mechanism of MAC is an important guarantee of it. The difference between the different MAC mechanisms lies in a channel allocation and channel access control problems. Channel allocation is responsible for the assigned to different node corresponding channel and eliminates the conflict between the communication link, and access control is responsible for avoiding conflict of different nodes in the access channel to achieve reasonable and efficient channel access. The research and improvement of multi-radio VANET MAC layer technology has important academic significance and application value.This topic is mainly to study the channel allocation algorithm and the access control mechanism of multi-radio multi-channel VANET. Firstly, as to the division of the on-board communication channel by the FCC, analyzing the deficiency of common channel allocation algorithm in VANET, using vehicle interactions between nodes, considering the current network status parameters, as measured by the channel performance factor to generate channel switching queue, this paper proposes a dynamic channel allocation algorithm CSQCA (Channel Switching Queue-based Channel Allocation) based on channel switching queue between two communication vehicle nodes.Secondly, as to distribution channel for multi-radio communication, analyzing the challenges of channel access for multi-radio VANET, and to consider the high load network characteristic caused by the multi-radio communication of all vehicles, using the advantages of TDMA technology and competitive channel access technology, this paper proposes a channel access technology TCCA (Time-division Competition Channel Access) based on vehicle interface status word.Then, on the basis of the above research, NS-2network simulation platform is established and the simulation module is extended. Using the simulation platform, the proposed channel allocation algorithm and channel access technology will be simulated and evaluated. Simulation results showed that CSQCA algorithm implements dynamic channel allocation in multi-radio VANET, reasonably solves the problem of the unreasonable channel allocation, and significantly improves the performance of the network. TCCA mechanism can adapt to high load on the network environment caused by the parallel multiple interface communication of vehicle nodes, Ensures that all vehicle nodes have equal opportunity to channel access, while maintaining the efficient utilization of network resources.Finally, the article lists some issues should be solved and the consummation, needs further to study, so as to lead to improvement direction for further research.