Network Coding And The Research Of Applications In Wireless Network

Network coding is proposed by the concept of information flow, which changes the traditional router's storage-transmit mode. Network coding is based on the idea that encoding and decoding operations are applied on the input information to maximize the multicast capacity. It is indicated from the resurch that network coding has advantages such as balancing the traffic, using bandwidth efficiently and providing higher network throughput.Firstly, the essential theory is presented. Through analyzing the typical algorithms of network coding in being, conclude their advantages and disadvantages. Wireless network provides the advantages for network coding, so the feasibility and the advantages of wireless network coding are analyzed.Secondly, a method of constructing variable-rate multicast code is proposed for network coding research. Based on information flow decomposition, multicast code of different dimensions in the case of fixed multicast members is constructed by exploiting the property of Vandermonde determinant. Performance is analyzed and the size of symbol field is deduced. Verify the validity of the method by an example.Finally, the application of network coding in retransmission of wireless network is studied. Through analyzing and comparing the traditional retransmission methods and the existing broadcast retransmission methods based on network coding, conclude their disadvantages. So a new broadcast retransmission method based on practical network coding is proposed. Practical network coding on lost packets from multiple different receivers is employed. Exploit the property of network coding that a packet includes information of multipacket so as to reduce the transmission numbers of acknowledgment signals. Theoretical analysis and simulation, which show the ability that the proposed scheme can reduce the consumed energy, verify the correctness and the advantages of the scheme.