Research On Multi-rate Multicast Transmit Mechanism Based On Network Coding

With the rapid development of communication technology,people's quality requirement of network application services have become increasingly demanding.Due to differences in the access network,different information processing capacity of receiving terminal nodes,heterogeneous nature has been one of the important features of the Internet.Multi-rate multicast technology has become a hot research direction in recent years by its effective in heterogeneous network.Multirate multicast technology allows each receiving node receives the same source data by selecting adaptive rate according to their capacity and network bandwidth,which has a good prospect in streaming media technology and remote multimedia communication network.This thesis studies two aspects including the application of network coding and multi-rate multicast network which mainly include the following.First study of network coding theory and implementation,unlike tranditional routing mode which forward information directly,network coding allows the intermediate nodes involved with encoding and decoding,which can encode the information before transmit it,there network coding can improve the network throughput by means of the compressed stream.In the realization of network coding mechanism mainly studies the principle and implementation approach of COPE.COPE is a kind of network coding based on packet level in wireless network,which can improve the network throughput through transmiting multiple data packets in one transmission process by compressing radio redundancy caused by the shared nature.Then summarize and analysis principle and advantages by studying multi-rate multicasting technology which include multi-layed and multiple description encoding multicast.By studying network coding application mode in multi-rate multicast network,using the encoding mechanism of COPE and multi-layed coding multicast,designed a multi-rate multicast network coding mechanism based on network coding considering three major factors based routing network coding,different transmission quality software and terminal handling.Designed a hierarchical encryption mechanism and the encoding mechanism between the layers,respectively for layered encoded source data is encrypted,for different levels of encoding data.Compared with traditional multi-rate multicast mechanism,simulation analysis proved that this mechanism has obvious transmission efficiency advantages,and by router based on network coding and decoding terminal software,each user can enjoy different service quality according to their different service requirements.