Research On Optimal Construction And Relevant Technology Of Network Coding For Multicast

With the rapid development of computer technology and network technology, the communication need in which multi-points need to receive data has increased day by day. Multicast communication technology is the best way to realize this kind of data transmission. With the birth of network coding technology, a new platform for the multicast communication has arised. Network coding based on multicast communication has become a concerned research subject.Network coding is a novel data transmission technique. Compared with traditional routing, intermediate nodes of a network can not only forward and copy information received from incoming links, but also encode it to generate new packets. Network coding can improve the data transmission performance, and has the advantage of improving the throughout of network, balancing network load, and increasing the robustness and security of network. However, it brings the coding cost in the process of transmitting data, owing to the encoding and recoding of nodes.The key to implement multicast communication with network coding is how to construct coding scheme, which dominates absolutely both the throughput and the coding cost of a network. Obviously, the two important objectives-improving the throughout and reducing the coding cost, are significant for multicast data transmission with network coding, then the study on the optimum construction of network coding for multicast communication is a research subject which has aroused wide attention.Based on the exist study on this field, this paper expands the research content. Aiming at the above two objectives, the content of research mainly focuses on the following three aspects:1) the study on the optimum construction of network coding to single source multicast connection in the unknown network topology environment; 2) the study on the relationship between the operation cost of network coding and environment parameters(Galois field,multicast rate,the length of data block); 3) the study on the optimum construction of network coding to multi-source multicast connection.First of all, the technique of generation and extension of linear network coding at different multicast rate has been put forward. Combined with random network coding, this paper has deduced some important properties which can help to implement single-source multicast connection with linear network coding and provide the most basic technical support for the next several issues to be solved. Aiming at the single-source multicast connection in which the source node can not get the global network topology knowledge and each sink node has the feedback path to the source node,by using the technique of generation and extension of linear network coding, this paper proposes data transmission strategies with network coding to implement the maximum network throughput. It has studied two cases:in static network environment, it puts forward a deterministic data transmission strategy with network coding; in the environment of network topology changing dynamically over time, it puts forward the strategy of testing multicast capacity and adjusting the multicast rate in the process of transmitting data, which can make the multicast rate adapt to the changes of network topology so as to improve the throughput of network.With the technique of generation and extension of linear network coding, aiming at single-source multicast network, based on some reasonable assumptions, this paper proposes a distributed network coding construction approach which can obtain the optimal coding scheme with maximal throughput and with the smallest number of coding channels. Compared with the approach in the existing literature, the proposed approach is not necessary to be given multicast rate and can achieve the maximum throughput.Besides,it can not only obtain the minimum number of coding channels, but also construct the corresponding coding scheme.This paper implements a precise analysis for time complexity of algebraic operations of Galois field. On this basis, a mathematic model for estimating the cost of network coding operations is established, and the precise relationship between computing costs and environment parameters is deduced, and then the key factor influencing the computing cost is analyzed and some important conclusions have been obtained, which can help to choose correctly environment parameters to reduce the computing cost.Aiming at the multi-source multi-sink multicast network, in which each source node needs to multicast data to all sink nodes, this paper proposes a linear network coding construction approach to implementing data transmission with maximum throughput. For a general multi-source multicast network, it has proposed a feasible linear network coding construction approach with sub-optimizing the network throughput. In terms of improving the network throughput, the analysis shows that, the proposed approach is superior to traditional routing.