Design Of File Transfer System Based On Digital Fountain Codes

Information is transmitted in the form of data packets in the Internet. Data packet loss takes place inevitably during the Internet transmission. The reliability of data transmission is extremely important in the file transfer system, it means that the file transmission is failed when the data is lost in the Internet. We must ensure the reliability of the data transmission. The TCP or UDP protocol is mainly used in the traditional file transfer system. The TCP protocol is connection-oriented protocol, it ensure the reliability of data transmission with acknowledgment, but the acknowledgment may reduce the data transmission rate, especially in the poor network environment, the TCP acknowledgment will use large amount of system resources. The UDP protocol is analogous to sending mail, the packet is routed through the network toward its destination without any guarantees that it will arrive, the packet may be lost enroute.Nevertheless, the data transmission rate is higher used UDP. In order to improve the data transmission rate,and guarantee the reliability of the data transmission, a new file transfer system is proposed in this paper, which uses UDP protocol combined with fountain codes.A performance simulation test for fountain codes is did in the first, including the test of different degrees distribution performance in the fountain code, and the simulation of different decoding algorithm, giving out the advantages and disadvantages of different decoding algorithm.In the design of the file transfer system, LT code is used as the most advanced property by now as the technology of forward error correction. as forward error correction technology to ensuring the reliability of data transmission, according to the performance simulation results of fountain codes, we selected the suitable degree distribution and decoding algorithm. Data transmission in the network is realized by UDP Socket. The file transfer system makes full use of the rateless characteristics of fountain codes, and combined with the higher transmission rate.Compared with the traditional file transfer system, the new file transfer system uses UDP protocol, provides higher transmission rate, and fountain code effectively guarantee the reliability of data transmission. The new file transfer system in this paper has higher transmission rate, especially in the case of poor network environment, it can still guarantee a higher file transfer rate.