Study On Multicast Routing And Video Transmission In Internet Of Vehicles

Internet of Things(IoT)is smartly changing various existing research areas into new themes,including smart health,smart home,smart industry,and smart transport.Evolving as one of the newest themes,Internet of Vehicles(IoV)has become one of the most promising areas of intensive research including the design and validation of its technology as well as the prospective safety and infoentertainment applications.In order to satisfy the high-speed propagation of different kinds of information under the dynamic networking topology of IoV,it is necessary to study routing protocols and file transmission mechanisms that are highly reliable,have low latency with low power consumption.Video transmission in IoV can not only help drivers with visual assistance,auxiliary prediction in terms of safety and optimize the process of traffic emergency responses,but also it acts as an important entertainment value-added features towards furture.In order to improve the performance of the video transmission mechanism in IoV,based on traditional three-node cooperative communication system,this paper applies a novel video coding scheme named SoftCast with coset mapping functions in the relaying process to optimize the performance of power allocation.The core idea of the proposed CVC-CM(Cooperative Video Coding with Coset Mapping)is choosing the node with better channel SNR to be the relaying node which needs to transmit its own given information from source after the coset mapping.So that the destination node can utilize information transmitted from the relay and source.Not only the power distribution effect by coset mapping can be optimized,but also the recovery video quality will be greatly improved by using the side information to help video rebuild.In the CVC-CM scheme,we also analyze the optimal step of filtering.To find it,we attain the empirical formula of optimal step with different channel SNR by doing experiments and analysis of a lot video examples.Through this formula we can adjust the filter step according to current channel quality to realize the improvement of the received video PSNR.At the same time,taking into account IoV has to face many challenges such as mobility,network size and other prominent features.General routing protocol does not apply to video transmission due to its unique features.The routing protocol based on geographical location and receiving nodes is found to be the most suitable routing protocol for video transmission.Under the multicast(one-to-many communications)cirumstances in IoV,the typical DRG(Distributed Robust Geocast)mechanism faces the problem that its packet delivery rate and end-to-end delay can be further improved.This paper utilizes the help of auxiliary RSU(Road Side Unit)and the broadcast mechanism of collision avoidance,proposes an advanced RSU-based multicast routing protocol by restricting the time delay of each receiving node in its rebroadcast moment and choosing the optimized slot to transmit the data packet.When respectively control the vehicle density,RSU distribution interval,the number of sending messages,broadcast radius and transmission power and other parameters,the experimental simulation results verify that compared with the improved flood mechanism and the traditional DRG mechanism,this new scheme shows the optimization of the packet delivery rate and end-to-end delay,and it can also improve the allocation and utilization of communicaition resources.