| Network coding significantly improve the performance of network data transmission which allows nodes to code the data, has changed traditional routing with store-and-forward. Because of the heterogeneity of the network, the data source node layered coding mechanism can effectively improve the network throughput for multi-rate transmission according to the actual situation of the network. The inter-layer hierarchical network coding is a combination of linear network coding for multicast source layered coding and the coding multi-rate linear network. Compared with the layered multicast network coding, the inter-layer hierarchical network coding can obtain higher utilization rate of network resource. This thesis mainly studies the optimization method of inter-layer hierarchical network coding in the heterogeneous network of single source sink.First, according to the shortage of fixed rate inter-layer hierarchical network coding scheme, this thesis studied adjustable rate inter-layer hierarchical network coding. In order to achieve the level of network coding layer and determine the optimal layer rate, an optimization method based on Genetic Algorithm is proposed for source coding rate.Second, according to the problem of network coding layer level cyber source utilization, this thesis presents a link code type optimization method based on Genetic Algorithms. The plan highlights the influence of the source output link on the encoding type of the network transmission performance and using Genetic operations fully embodies the characteristics of inter-layer hierarchical network coding. Compared with existing heuristic encoding type determination algorithm, the plan is applicable to a wider range of the network.Finally, based on Differential Evolution Algorithm, this thesis presents a Differential Evolution of inter-layer hierarchical network coding link code type optimization scheme. Compared with the scheme based on Genetic Algorithm, Differential Evolution Algorithm scheme has simple process of evolution and significantly improved the search speed. Simulation results show that, compared with the existing inter-layer hierarchical network coding schemes, based on this thesis of inter-layer hierarchical network coding optimization scheme, the two algorithm can obtain higher network total throughput for the single-source of heterogeneous network. |
