Design And Simulation Of AFEC Based On Active Network

With the rapid development of science,technology, and the emergence of various portable terminal device, people has higher and higher requirement for the quality of wireless communications. Relative to cable communication, data transmission in the network often happen s error, thus reducing the reliability of the transmission network due to the characteristics of wireless channel. Forward error correction as a way of error control, it can better eliminate the effects of packet loss in real time network. At present, most of the network is based on the end-to-end transmission system, and the error often occurs in the interior of the network. The traditional network adaptive forward error correction, although to a certain extent, can reduce the packet loss rate, but still can’t apply to network internal link differences flexibly, such as low coding error correction ability cannot effectively improve the quality of communication when it is used in the environment with poor link, and the error correction ability of higher coding in low packet loss rate of channel has higher redundancy.In order to solve these problems, active network is introduced in this topic. Active network uses the mode of transmission of storage, computing and forward; it not only has the ability of packet routing, but also can modify storage, and redirect the contents of the packet in the process of transmission. Programmability of active network node provides a convenient to users. Adaptive forward error correction based on active network can not only to detects error and correct it in the back end system, but can also process data of intermediate nodes in real-ti me, it increases not only the reliability of the system, but also improves the transfer efficiency of the network.At first, this paper analyzes the cause of packet loss, the error control method and the code using commonly, use the MATLB to build the simulation system and selected RS code to verify the deficiency of the current forward error correction algorithm. And then introduces the active network technology and the adaptive forward error correction, and adapts the forward error correction agreement into the active network, then using the simulation software NS2 to build simulation platform to simulate the active network, the experimental results show that the adaptive FEC based on active network can automatically adjust t he redundancy of FEC package to achieve the ideal effect of error correction according to the current link environment, it not only saves the bandwidth, but can also adapts to the internal links of the network.